ORCID Profile
0000-0003-1635-6506
Current Organisations
Stellenbosch University
,
Murdoch University
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Veterinary Sciences | Veterinary Microbiology (excl. Virology) | Veterinary Epidemiology | Veterinary Sciences not elsewhere classified
Livestock Product Traceability and Quality Assurance | Food Safety |
Publisher: American Society for Microbiology
Date: 02-08-2018
DOI: 10.1128/MRA.00869-18
Abstract: Staphylococcus aureus is a serious pathogen of humans and animals. Multilocus sequence type 612 is dominant and highly virulent in South African hospitals but relatively uncommon elsewhere.
Publisher: Public Library of Science (PLoS)
Date: 03-10-2011
Publisher: Australian Government Department of Health
Date: 15-09-2020
Abstract: From 1 January to 31 December 2019, thirty-nine institutions around Australia participated in the Australian Enterococcal Sepsis Outcome Programme (AESOP). The aim of AESOP 2019 was to determine the proportion of enterococcal bacteraemia isolates in Australia that were antimicrobial resistant, and to characterise the molecular epidemiology of the E. faecium isolates. Of the 1,361 unique episodes of bacteraemia investigated, 95.2% were caused by either E. faecalis (51.4%) or E. faecium (43.8%). Ampicillin resistance was not detected in E. faecalis but was detected in 91.1% of E. faecium. Vancomycin non-susceptibility was detected in 0.1% of E. faecalis and in 41.8% of E. faecium. Overall, 45.4% of E. faecium harboured vanA and/or vanB genes. For the vanA/vanB positive E. faecium isolates, 49.1% harboured vanA genes only and 50.6% vanB genes 0.3% harboured both vanA and vanB genes. The percentage of E. faecium bacteraemia isolates resistant to vancomycin in Australia is substantially higher than that seen in most European countries. E. faecium consisted of 78 multilocus sequence types (STs), of which 75.0% of isolates were classified into six major STs containing ten or more isolates. All major STs belong to clonal cluster (CC) 17, a major hospital-adapted polyclonal E. faecium cluster. The predominant STs (ST1424, ST17, ST796, ST80, ST1421, and ST78) were found across most regions of Australia. The most prevalent clone was ST1424, which was identified in all regions except the Northern Territory and Western Australia. Overall, 51.4% of isolates belonging to the six predominant STs harboured vanA or vanB genes. In 2019, AESOP has shown that enterococcal bacteraemias in Australia are frequently caused by polyclonal icillin-resistant high-level gentamicin-resistant vanA or vanB E. faecium which have limited treatment options.
Publisher: Elsevier BV
Date: 2001
Publisher: Elsevier BV
Date: 07-2023
Publisher: Wiley
Date: 02-1999
DOI: 10.1111/J.1445-5994.1999.TB01590.X
Abstract: Staphylococcus aureus invasive infection remains a serious condition associated with considerable morbidity and mortality. Following notification of five cases at Royal Darwin Hospital (RDH), we searched for related cases, determined their epidemiological characteristics and attempted to identify the source of this apparent cluster. We reviewed RDH microbiology records between June 1996 and April 1997 for S. aureus isolates with similar antibiograms to notified cases. We used antibiotic resistance patterns, bacteriophage typing and two molecular typing techniques to subtype implicated isolates. Hospital records were reviewed for admission details and associated costs were estimated. Fifty-four cluster-related isolates occurred in 47 separate presentations. The peak incidence was in the wet season. The most important risk factor for staphylococcal invasive infection was the presence of skin sores/scabies in 17/54 cases (31%), followed by intravascular line use in 14/54 (26%), open trauma in 11/54 (20%), underlying end stage renal failure and alcoholism each in ten of 54 (18%). The mean admission length was 30 days and antibiotics were given for an average of 23 days. Death due to S. aureus infection occurred in eight of 47 (17%) presentations. S. aureus pneumonia was community acquired in 12/13 patients (92%) and six of 13 (46%) died. Ten of 13 (80%) pneumonia patients had at least one other focus of S. aureus infection. The cost of antibiotics and hospital bed per presentation was approximately $16,000. Presentations with skin sores/scabies cost considerably more ($31,000). No common epidemiologic features were found for community or hospital acquired cases. Considerable mortality and cost was attributable to cases of S. aureus invasive infection during this cluster particularly those with community acquired pneumonia or skin sores/scabies. Staphylococcal antibiotic cover should be considered early for unwell patients presenting to hospital with pneumonia and other signs of potential S. aureus infection. It is appropriate to target public health efforts to prevent skin sores and to provide adequate treatment when they occur.
Publisher: Elsevier BV
Date: 07-2017
Publisher: Proceedings of the National Academy of Sciences
Date: 16-09-2200
Abstract: A small number of clonal lineages dominates the global population structure of methicillin-resistant Staphylococcus aureus (MRSA), resulting in the concept that MRSA has emerged on a few occasions after penicillinase-stable β-lactam antibiotics were introduced to clinical practice, followed by intercontinental spread of in idual clones. We investigated the evolutionary history of an MRSA clone (ST5) by mutation discovery at 108 loci (46 kb) within a global collection of 135 isolates. The SNPs that were ascertained define a radial phylogenetic structure within ST5 consisting of at least 5 chains of mutational steps that define geographically associated clades. These clades are not concordant with previously described groupings based on staphylococcal protein A gene ( spa ) typing. By mapping the number of independent imports of the staphylococcal cassette chromosome methicillin-resistance island, we also show that import has occurred on at least 23 occasions within this single sequence type and that the progeny of such recombinant strains usually are distributed locally rather than globally. These results provide strong evidence that geographical spread of MRSA over long distances and across cultural borders is a rare event compared with the frequency with which the staphylococcal cassette chromosome island has been imported.
Publisher: Elsevier BV
Date: 08-2018
DOI: 10.1016/J.VETMIC.2018.07.002
Abstract: This study used phenotypic tests and whole genome sequencing to characterise a collection of 37 clinical Staphylococcus felis isolates from cats. S les were isolated from a range of diseases including feline lower urinary tract disease (n = 15), otitis externa (n = 13), and ocular disease (n = 2). Isolates were identified using MALDI-TOF MS and by BLASTn analysis of S. felis-specific 16S rRNA, rpoB and nuc genes in whole genome sequence-based contigs. Phenotypic antimicrobial resistance was determined using disk diffusion and broth microdilution. Coagulase activity was assessed using feline and rabbit plasma. Genomes were screened for putative virulence and antimicrobial resistance genes using the sequences of known genes from other staphylococci as homologous references. Phylogenetic relationships were inferred using single nucleotide polymorphisms. One isolate was coagulase-positive when tested with feline plasma but all isolates were rabbit plasma coagulase-negative. No genetic determinant of coagulase activity was identified in this isolate. A range of putative virulence genes were found amongst isolates including genes associated with adhesion, toxin production and immune evasion. Ninety two percent of isolates were fully susceptible to all antimicrobials tested, which was reflected by a general absence of resistance genes. Clustering within the phylogenetic tree suggested a multiclonal population structure this clustering did not correlate with disease syndrome or geographic origin of the isolate. Future studies of veterinary staphylococci will benefit from the publicly available S. felis draft genomes that were generated in this study.
Publisher: American Society for Microbiology
Date: 06-2012
DOI: 10.1128/JCM.06456-11
Abstract: We report the molecular epidemiology of 27 clinical multidrug-resistant Staphylococcus epidermidis (MDRSE) isolates collected between 2003 and 2007 in an Australian teaching hospital. The dominant genotype (sequence type 2 [ST2]) accounted for 85% of the isolates tested and was indistinguishable from an MDRSE genotype identified in European hospitals, which may indicate that highly adaptable health care-associated genotypes of S. epidermidis have emerged and disseminated worldwide in the health care setting.
Publisher: Oxford University Press (OUP)
Date: 04-10-2005
DOI: 10.1093/JAC/DKI351
Publisher: American Society for Microbiology
Date: 08-2014
DOI: 10.1128/JCM.00021-14
Abstract: Active surveillance is part of a multifaceted approach used to prevent the spread of vancomycin-resistant enterococci (VRE). The impact of fecal density, the vancomycin MIC of the isolate, and the vancomycin concentration in liquid medium on test performance are uncertain. Using fecal specimens spiked with a collection of 18 VRE (predominantly vanB ) with a wide vancomycin MIC range, we compared the performances of commercial chromogenic agars (CHROMagar VRE, chromID VRE, Brilliance VRE, and VRE Select) and 1 liquid medium (Enterococcosel enrichment broth) for VRE detection. The specificity of solid media was excellent however, the sensitivity at 48 h varied from 78 to 94%. Screening using liquid medium was less sensitive than screening with solid media, particularly as the vancomycin content increased. Sensitivity declined (i) as the fecal VRE density decreased, (ii) when the media were assessed at 24 h (versus 48 h), and (iii) for isolates with a low vancomycin MIC (sensitivity, 25 to 75% versus 100% for isolates with vancomycin MIC of mg/liter versus mg/liter on solid medium using 10 6 CFU/ml of feces). Depending on local epidemiology and in particular VRE vancomycin MICs, the sensitivity of culture-based methods for VRE screening of stool or rectal specimens may be suboptimal, potentially facilitating secondary transmission.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 02-2006
Abstract: Community-associated methicillin-resistant Staphylococcus aureus (MRSA) was first reported in Western Australia in the early 1990s from indigenous peoples living in remote areas. Although a statewide policy of screening all hospital patients and staff who have lived outside the state for MRSA has prevented the establishment of multidrug-resistant epidemic MRSA, the policy has not prevented SCCmec type IV and type V MRSA clones from becoming established. Of the 4,099 MRSA isolates analyzed (referred to the Gram-positive Bacteria Typing and Research Unit) from July 2003 to December 2004, 77.5% were community-associated MRSA (CA-MRSA). Using multilocus sequence/staphylococcal chromosome cassette mec typing, 22 CA-MRSA clones were characterized. Of these isolates, 55.5% were resistant to >1 non-beta-lactam antimicrobial drug. Five Panton-Valentine leukocidin (PVL)-positive CA-MRSA clones were identified. The emergence of multidrug-resistant CA-MRSA clones and the detection of PVL toxin genes in clones previously reported as PVL negative is a major public health concern.
Publisher: Oxford University Press (OUP)
Date: 2011
DOI: 10.1093/CID/CIQ067
Abstract: There is significant ersity in methicillin-resistant Staphylococcus aureus (MRSA) clones arising in the community worldwide, with considerable geographical differences in typical antimicrobial resistance profiles. Many community clones of MRSA have a non-multidrug resistant antimicrobial profile, providing increased options for empirical and directed therapy of infections caused by these strains. However, the recent description of increasing non-β lactam resistance in community clones of MRSA, especially USA300, provides a timely warning for clinicians making decisions about therapy for patients potentially infected with these strains. Continued monitoring of global epidemiology and emerging drug resistance data is critical for the effective management of these infections.
Publisher: Springer Netherlands
Date: 2010
Publisher: Springer Netherlands
Date: 2010
Publisher: Cambridge University Press (CUP)
Date: 24-04-2014
DOI: 10.1017/S0950268814000983
Abstract: Diverse strain types of methicillin-resistant Staphylococcus aureus (MRSA) cause infections in community settings worldwide. To examine heterogeneity of spread within households and to identify common risk factors for household transmission across settings, primary data from studies conducted in New York (USA), Breda (The Netherlands), and Melbourne (Australia) were pooled. Following MRSA infection of the index patient, household members completed questionnaires and provided nasal swabs. Swabs positive for S. aureus were genotyped by spa sequencing. Poisson regression with robust error variance was used to estimate prevalence odds ratios for transmission of the clinical isolate to non-index household members. Great ersity of strain types existed across studies. Despite differences between studies, the index patient being colonized with the clinical isolate at the home visit ( P 0·01) and the percent of household members aged years ( P 0·01) were independently associated with transmission. Targeted decolonization strategies could be used across geographical settings to limit household MRSA transmission.
Publisher: Oxford University Press (OUP)
Date: 11-2002
DOI: 10.1093/JAC/DKF238
Abstract: The mecA gene that encodes methicillin resistance in Staphylococcus aureus may be regulated by the mecR1 and mecI genes, and this region has been referred to as the mec complex. An analysis of these regulatory genes in 35 epidemic methicillin-resistant S. aureus (MRSA) isolated in England and Australia has found that they contain three classes of mec complex. Firstly, the Class A mec complex with complete mecR1 and mecI genes. Secondly, a new variant of Class A, the Class A1 mec complex, with a 166 bp deletion in the membrane-spanning domain of mecR1 and a complete mecI gene. Thirdly, the Class B mec complex, in which the penicillin-binding domain of mecR1 and the whole mecI gene are deleted by the insertion of a partial sequence of IS1272. Seven MRSA isolated in England and Australia over different time periods had the Class A mec complex. However, the isolates did not have closely related pulsed-field gel electrophoresis (PFGE) patterns. The Class A1 mec complex was found in 12 Australian isolates and the English epidemic MRSA, EMRSA-1. All these organisms were isolated in the early 1980s and had closely related PFGE patterns. The Class B mec complex region was found in nine EMRSA and seven Australian MRSA isolated over the period from the 1970s to 2000. These isolates had related PFGE patterns. The mecA region was also compared in the isolates and all but two of the isolates had an XbaI restriction site. These results support the global spread of epidemic clones and confirm the close relationship between the Australian and English MRSA strains.
Publisher: Frontiers Media SA
Date: 25-08-2020
Publisher: Elsevier BV
Date: 11-2020
Publisher: Elsevier BV
Date: 12-2011
Publisher: Oxford University Press (OUP)
Date: 02-2020
DOI: 10.1093/GBE/EVAA023
Abstract: Neisseria spp. possess four genogroups of filamentous prophages, termed Nf1 to 4. A filamentous bacteriophage from the Nf1 genogroup termed meningococcal disease-associated phage (MDA φ) is associated with clonal complexes of Neisseria meningitidis that cause invasive meningococcal disease. Recently, we recovered an isolate of Neisseria gonorrhoeae (ExNg63) from a rare case of gonococcal meningitis, and found that it possessed a region with 90% similarity to Nf1 prophages, specifically, the meningococcal MDA φ. This led to the hypothesis that the Nf1 prophage may be more widely distributed amongst the genus Neisseria. An analysis of 92 reference genomes revealed the presence of intact Nf1 prophages in the commensal species, Neisseria lactamica and Neisseria cinerea in addition to the pathogen N. gonorrhoeae. In N. gonorrhoeae, Nf1 prophages had a restricted distribution but were present in all representatives of MLST ST1918. Of the 160 phage integration sites identified, only one common insertion site was found between one isolate of N. gonorrhoeae and N. meningitidis. There was an absence of any obvious conservation of the receptor for prophage entry, PilE, suggesting that the phage may have been obtained by natural transformation. An examination of the restriction modification systems and mutated mismatch repair systems with prophage presence suggested that there was no obvious preference for these hosts. A timed phylogeny inferred that N. meningitidis was the donor of the Nf1 prophages in N. lactamica and N. gonorrhoeae. Further work is required to determine whether Nf1 prophages are active and can act as accessory colonization factors in these species.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 08-2017
Publisher: Oxford University Press (OUP)
Date: 07-1998
DOI: 10.1093/JAC/42.1.67
Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) is endemic in teaching hospitals in eastern Australian states, with prevalence rates averaging 25-30% of all S. aureus. Between 1990 and 1995, 1467 non-duplicate MRSA isolates from clinically infected sites were tested in Sydney, Melbourne, and Brisbane as part of a national survey of staphylococcal susceptibility. We reviewed the differing evolution of resistance to ciprofloxacin, rif icin, and fusidic acid. Despite similarities in community and hospital antibiotic use and MRSA prevalence rates, trends in resistance to the oral antibiotics in these cities have progressed independently of each other. In the 1995 survey in in idual hospitals in Melbourne, 16-24% of strains were ciprofloxacin-resistant, compared with 80-100% in Sydney and 30-44% in Brisbane. There was great ersity of phage type patterns for ciprofloxacin-resistant strains, suggesting heterogeneous development of resistance. Rif icin resistance was more closely associated with distinct dominant epidemic phage types, common to institutions in the same city, but without spread to the other cites. Between 1990 and 1995, these comprised 30-60% of all MRSA in Brisbane, compared with 5-10% in Melbourne and < 25% in Sydney. Fusidic acid resistance was uncommon and sporadic (< 5%), and was distributed equally between methicillin-resistant and methicillin-susceptible strains. Resistance to the oral agents in MRSA is due to a complex mix of antibiotic selection pressures and cross-infection with local and epidemic strains in closely related institutions. Each of these mechanisms can predominate, dependent on local factors and the antibiotics used.
Publisher: Elsevier BV
Date: 10-2023
Publisher: Australian Government Department of Health
Date: 15-10-2020
Abstract: The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2018 survey was the sixth year to focus on bloodstream infections, and included Enterobacterales, Pseudomonas aeruginosa and Acinetobacter species. Eight thousand three hundred and fifty isolates, comprising Enterobacterales (7,512, 90.0%), P. aeruginosa (743, 8.9%) and Acinetobacter species (95, 1.1%), were tested using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2019). Of the key resistances, resistance to the third-generation cephalosporin, ceftriaxone, was found in 13.4%/13.4% of Escherichia coli (CLSI/EUCAST criteria), and 9.4%/9.4% of Klebsiella pneumoniae. Resistance rates to ciprofloxacin were 15.2%/15.2% for E. coli, 11.3%/11.3% for K. pneumoniae, 7.4%/7.4% for Enterobacter cloacae complex, and 3.6%/7.7% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 3.0%/6.0%, 4.3%/7.9%, 18.2%/22.0%, and 5.1%/11.1% for the same five species respectively. Thirty-one isolates from 27 patients were shown to harbour a carbapenemase gene: 14 blaIMP-4 (11 patients), including one with blaIMP-4+blaOXA-23, four blaKPC (three patients), three blaOXA-48, three blaNDM, three blaGES. two blaOXA-181, and two blaOXA-23.
Publisher: American Society for Microbiology
Date: 24-12-2019
Abstract: The Bengal Bay clone (ST772) is a community-associated and multidrug-resistant Staphylococcus aureus lineage first isolated from Bangladesh and India in 2004. In this study, we showed that the Bengal Bay clone emerged from a virulent progenitor circulating on the Indian subcontinent. Its subsequent global transmission was associated with travel or family contact in the region. ST772 progressively acquired specific resistance elements at limited cost to its fitness and continues to be exported globally, resulting in small-scale community and health care outbreaks. The Bengal Bay clone therefore combines the virulence potential and epidemiology of community-associated clones with the multidrug resistance of health care-associated S. aureus lineages. This study demonstrates the importance of whole-genome sequencing for the surveillance of highly antibiotic-resistant pathogens, which may emerge in the community setting of regions with poor antibiotic stewardship and rapidly spread into hospitals and communities across the world.
Publisher: Oxford University Press (OUP)
Date: 29-01-2014
DOI: 10.1093/GBE/EVU022
Publisher: Oxford University Press (OUP)
Date: 2003
DOI: 10.1080/13693780310001600435
Abstract: We developed a standardized DNA sequence-based approach for the accurate and timely identification of medically important fungi by sequencing polymerase chain reaction (PCR) products with a rapid automated capillary electrophoresis system. A simple DNA extraction method and PCR lification using universal fungal primers was used to lify ribosomal DNA from a range of clinical isolates and reference strains. The entire internal transcribed spacer (ITS) 1-5.8S-ITS2 ribosomal DNA region was sequenced using automated dye termination sequencing for 89 clinical isolates. These had previously been identified by traditional methods and included 12 ascomycetous yeast species, three basidiomycetous yeast species, eight dermatophyte species and two thermally dimorphic fungi, Scedosporium prolificans and S. apiospermum. Furthermore, 21 reference strains representing 19 different Candida species, Geotrichum candidum and Malassezia furfur were also sequenced as part of this study and were used either as standards for sequence-based comparisons, or as assay controls. Sequence-based identification was compared to traditional identification in a blinded manner. Of the clinical isolates tested, 88/89 had DNA sequences that were highly homologous to those of reference strains accessioned in GenBank, and 87/89 gave a sequence-based identification result that correlated with the traditional identification. In contrast to relatively slow conventional methods of identification, a sequence-based identification from a pure culture can be obtained within 24 h of a DNA extraction carried out after a minimal period of culture growth. We conclude that this approach is rapid, and may be a more accurate cost-effective alternative than most phenotypic methods for identification of many medically important fungi frequently encountered in a routine diagnostic microbiology laboratory.
Publisher: Springer Science and Business Media LLC
Date: 11-10-2009
DOI: 10.1007/S10096-008-0632-1
Abstract: The objective was to compare the epidemiology and outcome of healthcare- (HA-) and community-associated (CA-) MRSA bacteraemia. A 10-year retrospective study of MRSA bacteraemia was carried out. Episodes were classified according to established criteria. Molecular typing was performed on a subset of isolates. Of 197 MRSA bacteraemia episodes, 178 (90.4%) were classified as HA-MRSA and 19 (9.6%) as CA-MRSA. All-cause 7- and 30-day mortality rates were similar in the HA and CA-MRSA bacteraemia groups however, 1-year mortality was higher in the HA-MRSA bacteraemia group (48.3% vs 21.1% [p = 0.023]). Thirty-day all-cause mortality was significantly lower if empiric antimicrobial therapy included agent(s) to which the isolate tested susceptible, compared with patients receiving "inactive" therapy (19% vs 35.1% [p = 0.011]). The majority of MRSA bacteraemia episodes were caused by clones known to circulate in the community. All-cause mortality is as high in HA- as in CA-MRSA bacteraemia. Thirty-day mortality was significantly reduced if the patient received an antibiotic with activity against the MRSA isolate.
Publisher: Wiley
Date: 10-2014
DOI: 10.1002/ALR.21423
Abstract: Staphylococcus aureus infection is known to play a role in recalcitrant chronic rhinosinusitis (CRS). However, it is unknown if recurrent S. aureus infections are caused by the same strain or are due to independent acquisitions of different strains. S les were collected from patients with CRS from July 2011 to August 2012. S. aureus was isolated from mucosal swabs and tissue specimens from patients who underwent surgery during the study period, or from swabs of areas of purulence taken in the postoperative period under endoscopic guidance. Pulsed-field gel electrophoresis was used to characterize S. aureus isolates. Thirty-four patients were included in the study 79% showed persistence of the same S. aureus strain in their paranasal sinuses (p = 0.001 H1 ≠ 50%). Furthermore, a significantly high frequency of patients with known biofilm status were positive for S. aureus biofilm (p = 0.002 H1 ≠ 50%). When patients were stratified according to disease evolution postsurgery, certain strains appeared to be more commonly associated with symptom persistence. The same S. aureus strain appears to persist in the paranasal sinuses of CRS patients despite multiple courses of culture-directed antibiotics. This suggests that conventional antimicrobial therapies in patients with CRS may not eliminate the organism. This may be partly explained by the formation of biofilms in the paranasal sinus region.
Publisher: Elsevier BV
Date: 07-2018
Publisher: Elsevier BV
Date: 12-2013
Publisher: Springer Science and Business Media LLC
Date: 2011
Publisher: Australian Government Department of Health
Date: 15-10-2020
Abstract: The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric gram-negative pathogens. The 2019 survey was the seventh year to focus on bloodstream infections, and included Enterobacterales, Pseudomonas aeruginosa and Acinetobacter species. Eight thousand eight hundred and fifty-seven isolates, comprising Enterobacterales (7,983 90.1%), P. aeruginosa (764 8.6%) and Acinetobacter species (110 1.2%), were tested using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2020). Of the key resistances, resistance to the third-generation cephalosporin ceftriaxone was found in 13.3%/13.3% (CLSI/EUCAST criteria) of Escherichia coli and 8.4%/8.4% of Klebsiella pneumonia. Resistance rates to ciprofloxacin were 16.0%/16.0% for E. coli, 10.2%/10.2% for K. pneumonia complex, 5.9%/5.9% for Enterobacter cloacae complex, and 4.1%/9.3% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 3.2%/5.7%, 4.7%/8.5%, 14.8%/21.4%, and 6.9%/12.5% for the same four species/complex respectively. Twenty-nine isolates from 29 patients were shown to harbour a carbapenemase gene: 15 blaIMP-4, five blaOXA-181, four blaOXA-23 (one with blaOXA-58 also), three blaNDM-4/5, one blaGES-5, and one blaIMP-1
Publisher: Microbiology Society
Date: 09-2014
Abstract: Meticillin-resistant Staphylococcus pseudintermedius (MRSP) has recently emerged as a worldwide cause of canine pyoderma. In this study, we characterized 22 S. pseudintermedius isolates cultured from 19 dogs with pyoderma that attended a veterinary dermatology referral clinic in Australia in 2011 and 2012. Twelve isolates were identified as MRSP by mecA real-time PCR and phenotypic resistance to oxacillin. In addition to β-lactam resistance, MRSP isolates were resistant to erythromycin (91.6 %), gentamicin (83.3 %), ciprofloxacin (83.3 %), chlor henicol (75 %), clindamycin (66 %), oxytetracycline (66 %) and tetracycline (50 %), as shown by disc-diffusion susceptibility testing. Meticillin-susceptible S. pseudintermedius isolates only showed resistance to penicillin/ icillin (90 %) and tetracycline (10 %). PFGE using the Sma I restriction enzyme was unable to type nine of the 12 MRSP isolates. However the nine isolates provided the same PFGE pulsotype using the Cfr 91 restriction enzyme. Application of the mec -associated direct repeat unit ( dru ) typing method identified the nine Sma I PFGE-untypable isolates as dt11cb, a dru type that has only previously been associated with MRSP sequence type (ST)45 isolates that possess a unique SCC mec element. The dt11cb isolates shared a similar multidrug-resistant antibiogram phenotype profile, whereas the other MRSP isolates, dt11a, dt11af (dt11a-associated) and dt10h, were resistant to fewer antibiotic classes and had distinct PFGE profiles. This is the first report of MRSP causing pyoderma in dogs from Australia. The rapid intercontinental emergence and spread of multidrug-resistant MRSP strains confirms the urgent need for new treatment modalities for recurrent canine pyoderma in veterinary practice.
Publisher: Elsevier BV
Date: 2018
Publisher: American Society for Microbiology
Date: 10-2004
DOI: 10.1128/JCM.42.10.4735-4743.2004
Abstract: Increasing reports of the appearance of novel nonmultiresistant methicillin-resistant Staphylococcus aureus MRSA (MRSA) strains in the community and of the spread of hospital MRSA strains into the community are cause for public health concern. We conducted two national surveys of unique isolates of S. aureus from clinical specimens collected from nonhospitalized patients commencing in 2000 and 2002, respectively. A total of 11.7% of 2,498 isolates from 2000 and 15.4% of 2,486 isolates from 2002 were MRSA. Approximately 54% of the MRSA isolates were nonmultiresistant (resistant to less than three of nine antibiotics) in both surveys. The majority of multiresistant MRSA isolates in both surveys belonged to two strains (strains AUS-2 and AUS-3), as determined by pulsed-field gel electrophoresis (PFGE) and resistogram typing. The 3 AUS-2 isolates and 10 of the 11 AUS-3 isolates selected for multilocus sequence typing (MLST) and staphylococcal chromosomal cassette mec (SCC mec ) analysis were ST239-MRSA-III (where ST is the sequence type) and thus belonged to the same clone as the eastern Australian MRSA strain of the 1980s, which spread internationally. Four predominant clones of novel nonmultiresistant MRSA were identified by PFGE, MLST, and SCC mec analysis: ST22-MRSA-IV (strain EMRSA-15), ST1-MRSA-IV (strain WA-1), ST30-MRSA-IV (strain SWP), and ST93-MRSA-IV (strain Queensland). The last three clones are associated with community acquisition. A total of 14 STs were identified in the surveys, including six unique clones of novel nonmultiresistant MRSA, namely, STs 73, 93, 129, 75, and 80slv and a new ST. SCC mec types IV and V were present in erse genetic backgrounds. These findings provide support for the acquisition of SCC mec by multiple lineages of S. aureus . They also confirm that both hospital and community strains of MRSA are now common in nonhospitalized patients throughout Australia.
Publisher: Elsevier BV
Date: 08-2014
DOI: 10.1016/J.MCP.2013.11.003
Abstract: Staphylococcus aureus is a human pathogen that can harbour several genes encoding exotoxins including leukocidins. A clinically most relevant factor is Panton-Valentine leukocidin (PVL) because of its association with chronic, recurrent or severe skin and soft tissue infections. In this study an antibody array was designed and used to obtain an overview about the in vitro PVL expression levels of 266 clinical isolates of MRSA as well as of MSSA belonging to a wide variety of clonal complexes. For that purpose, a novel precipitation based method was used. Unknown PVL concentrations were determined by mapping the signal intensities for spotted monoclonal antibodies to calibration curves that resulted from experiments with known concentrations of recombinant LukF-PV. In most cases, isolates belonging to one clonal complex (CC) showed similar PVL expressions. However, there were also CCs with widely varying PVL concentrations. First analyses, based on in vitro PVL measurements, showed low PVL concentrations in isolates from severe and fatal conditions that are not associated with PVL, such as sepsis, while isolates from skin and soft tissue infections yielded higher concentrations. Agr-group I and IV isolates generally produced more PVL than isolates from agr-groups II and III. The few isolates harbouring the gene encoding toxic shock syndrome toxin (tst1) were particularly low level PVL producers. However, these issues warrant further studies. The method described herein allows rapid quantification of expressed proteins such as PVL in collections of clinical isolates in order to correlate with clinical or genotypic data with a potential for further parallelisation.
Publisher: Cambridge University Press (CUP)
Date: 18-07-2013
DOI: 10.1017/S0950268813001581
Abstract: Community-acquired Staphylococcus aureus infections are a public health concern, yet little is known about infections that do not present to hospital. We identified community-onset S. aureus infections via specimens submitted to a community-based pathology service. Referring doctors confirmed eligibility and described infection site, severity and treatment. Isolates were characterized on antibiotic resistance, PFGE, MLST/SCC mec , and Panton–Valentine leukocidin (PVL), representing 106 community-onset infections 34 non-multiresistant methicillin-resistant S. aureus (nmMRSA) (resistant to non- β -lactam antibiotics), 15 multiply antibiotic-resistant MRSA (mMRSA) and 57 methicillin-sensitive S. aureus (MSSA). Most (93%) were skin and soft tissue infections. PVL genes were carried by 42% of nmMRSA isolates [95% confidence interval (CI) 26–61] and 15% of MSSA (95% CI 8–28). PVL was associated with infections of the trunk, head or neck (56·4% vs . 24·3%, P = 0·005) in younger patients (23 vs . 52 years, P 0·001), and with boils or abscesses (OR 8·67, 95% CI 2·9–26·2), suggesting underlying differences in exposure and/or pathogenesis.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 08-2018
DOI: 10.1126/SCITRANSLMED.AAR6115
Abstract: Alcohol-based disinfectants and particularly hand rubs are a key way to control hospital infections worldwide. Such disinfectants restrict transmission of pathogens, such as multidrug-resistant
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 2019
Publisher: PeerJ
Date: 24-01-2017
DOI: 10.7717/PEERJ.2916
Abstract: From early 2012, a novel clone of vancomycin resistant Enterococcus faecium (assigned the multi locus sequence type ST796) was simultaneously isolated from geographically separate hospitals in south eastern Australia and New Zealand. Here we describe the complete genome sequence of Ef_aus0233, a representative ST796 E. faecium isolate. We used PacBio single molecule real-time sequencing to establish a high quality, fully assembled genome comprising a circular chromosome of 2,888,087 bp and five plasmids. Comparison of Ef_aus0233 to other E. faecium genomes shows Ef_aus0233 is a member of the epidemic hospital-adapted lineage and has evolved from an ST555-like ancestral progenitor by the accumulation or modification of five mosaic plasmids and five putative prophage, acquisition of two cryptic genomic islands, accrued chromosomal single nucleotide polymorphisms and a 80 kb region of recombination, also gaining Tn 1549 and Tn 916 , transposons conferring resistance to vancomycin and tetracycline respectively. The genomic dissection of this new clone presented here underscores the propensity of the hospital E. faecium lineage to change, presumably in response to the specific conditions of hospital and healthcare environments.
Publisher: Proceedings of the National Academy of Sciences
Date: 20-11-2017
Abstract: USA300 is a hypervirulent, community-acquired, multidrug-resistant Staphylococcus aureus clone that started to spread in the United States around 17 years ago. Many studies detected it also in South America, Europe, and the Asia-Pacific region. In this study, we show that USA300 is also circulating in sub-Saharan Africa. Locating the temporal and spatial origin of clonal lineages is important with respect to epidemiology and molecular evolution of pathogens. We show that USA300 evolved from a less virulent and less resistant ancestor circulating in Central Europe around 160 years ago. Constant surveillance of pathogen transmission routes is vital to prevent and control potential outbreaks. Whole genome sequencing proved to be a useful tool for epidemiological surveillance.
Publisher: American Society for Microbiology
Date: 05-2010
DOI: 10.1128/AAC.01287-09
Abstract: Clonal complex 59 (CC59) community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains were characterized using pulsed-field gel electrophoresis, spa typing, multilocus sequence typing, diagnostic DNA microarrays, and PCRs targeting staphylococcal cassette chromosome mec (SCC mec ) elements and Panton-Valentine leukocidin (PVL). Six distinct groups within CC59 were characterized. At least seven different variants of SCC mec elements were identified (IVa [2B], IVb [2B], IVd [2B], IV variant [2B], IVa [2B& ], V variant [5C2], and V [5C2& ]). (The structural type is indicated by a Roman numeral, with a lowercase letter indicating the subtype, and the ccr complex and the mec complex are indicated by an Arabic numeral and an uppercase letter, respectively. Where there is an extra ccr element, this is indicated by “& ” and an Arabic numeral designating the ccr type.) The first group is similar to the American sequence type 59 (ST59) MRSA-IV CA-MRSA strain USA1000. The second group includes a PVL-negative ST87 strain with an SCC mec element of subtype IVb (2B). The third group comprises PVL-variable ST59 MRSA-IV strains harboring multiple SCC mec IV subtypes. PVL-negative ST59 MRSA strains with multiple or composite SCC mec elements (IVa [2B& ]) form the fourth group. Group 5 corresponds to the internationally known “Taiwan clone,” a PVL-positive strain with a variant SCC mec element (V [5C2& ]). This strain proved to be the most common CC59 MRSA strain isolated in Western Australia. Finally, group 6 encompasses the ST59 MRSA-V variant (5C2). The differentiation of CC59 into groups and strains indicates a rapid evolution and spread of SCC mec elements. Observed differences between groups of strains as well as intrastrain variability within a group facilitate the tracing of their spread.
Publisher: Elsevier BV
Date: 04-2022
DOI: 10.1016/J.IJANTIMICAG.2022.106577
Abstract: Clonal complex 398 (CC398) livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has been reported worldwide in a variety of food-animal species. Although CC398 is synonymous with LA-MRSA, community-associated MRSA (CA-MRSA) variants have emerged, including the Panton-Valentine leukocidin (PVL)-positive ST398-V and ST398 single-locus variant ST1232-V, and the PVL-negative ST398-V clones. Using comparative genomic analysis, we determined whether ten CC398 MRSA bacteraemia episodes recently identified in Australia were due to LA-MRSA or CA-MRSA CC398. Isolates were sourced from the Australian Group on Antimicrobial Resistance S. aureus surveillance programme and episodes occurred across Australia. Whole-genome sequencing (WGS) and phylogenetic comparison of the ten CC398 bacteraemia isolates with previously published CC398 MRSA whole-genome sequences identified that the Australian CC398 isolates were closely related to the human-associated II-GOI clade and the livestock-associated IIa clade. The identified CC398 MRSA clones were: PVL-positive ST1232-V (5C2 ), PVL-negative community-associated ST398-V (5C2 ) and livestock-associated ST398-V (5C2 ). Our findings demonstrate the importance of using WGS and comparing the sequences with international sequences to distinguish between CC398 CA-MRSA and LA-MRSA and to determine the isolates' origin. Furthermore, our findings suggest that CC398 CA-MRSA has become established in the Australian community and that ST398-V (5C2 ) LA-MRSA is now widespread in Australian piggeries. Our study emphasises the need for national One Health antimicrobial resistance surveillance programmes to assist in monitoring the ongoing epidemiology of MRSA and other clinically significant antimicrobial-resistant organisms.
Publisher: Springer Science and Business Media LLC
Date: 22-03-2018
DOI: 10.1186/S13756-018-0335-Z
Abstract: Vancomycin-resistant Enterococcus faecium (VRE) is a leading cause of hospital-acquired infections. New, presumably better-adapted strains of VRE appear unpredictably it is uncertain how they spread despite improved infection control. We aimed to investigate the relatedness of a novel sequence type (ST) of vanB E. faecium - ST796 - very near its time of origin from hospitals in three Australian states and New Zealand. Following near-simultaneous outbreaks of ST796 in multiple institutions, we gathered then tested colonization and bloodstream infection isolates’ antimicrobial resistance (AMR) phenotypes, and phylogenomic relationships using whole genome sequencing (WGS). Patient meta-data was explored to trace the spread of ST796. A novel clone of vanB E. faecium (ST796) was first detected at one Australian hospital in late 2011, then in two New Zealand hospitals linked by inter-hospital transfers from separate Melbourne hospitals. ST796 also appeared in hospitals in South Australia and New South Wales and was responsible for at least one major colonization outbreak in a Neonatal Intensive Care Unit without identifiable links between centers. No exceptional AMR was detected in the isolates. While WGS analysis showed very limited ersity at the core genome, consistent with recent emergence of the clone, clustering by institution was observed. Evolution of new E. faecium clones, followed by recognized or unrecognized movement of colonized in iduals then rapid intra-institutional cross-transmission best explain the multi-center, multistate and international outbreak we observed.
Publisher: Frontiers Media SA
Date: 06-06-2016
Publisher: Public Library of Science (PLoS)
Date: 25-04-2013
Publisher: Elsevier BV
Date: 2020
Publisher: Informa UK Limited
Date: 07-2016
Publisher: Cambridge University Press (CUP)
Date: 05-08-2019
DOI: 10.1017/ICE.2019.202
Abstract: To describe an outbreak of bacteremia caused by vancomycin-sensitive Enterococcus faecalis (VSEfe). An investigation by retrospective case control and molecular typing by whole-genome sequencing (WGS). A tertiary-care neonatal unit in Melbourne, Australia. Risk factors for 30 consecutive neonates with VSEfe bacteremia from June 2011 to December 2014 were analyzed using a case control study. Controls were neonates matched for gestational age, birth weight, and year of birth. Isolates were typed using WGS, and multilocus sequence typing (MLST) was determined. Bacteremia for case patients occurred at a median time after delivery of 23.5 days (interquartile range, 14.9–35.8). Previous described risk factors for nosocomial bacteremia did not contribute to excess risk for VSEfe. WGS typing results designated 43% ST179 as well as 14 other sequence types, indicating a polyclonal outbreak. A multimodal intervention that included education, insertion checklists, guidelines on maintenance and access of central lines, adjustments to the late onset sepsis antibiotic treatment, and the introduction of diaper bags for disposal of soiled diapers after being handled inside the bed, led to termination of the outbreak. Typing using WGS identified this outbreak as predominately nonclonal and therefore not due to cross transmission. A multimodal approach was then sought to reduce the incidence of VSEfe bacteremia.
Publisher: European Centre for Disease Control and Prevention (ECDC)
Date: 17-11-2016
DOI: 10.2807/1560-7917.ES.2016.21.46.30396
Abstract: Following the reported link between heater–cooler unit (HCU) colonisation with Mycobacterium chimaera and endocarditis, mycobacterial s ling of all HCUs in use in Western Australia was initiated from August 2015, revealing M. chimaera colonisation in 10 of 15 HCUs. After M. chimaera was isolated from a pleural biopsy from a cardiothoracic patient who may have been exposed to a colonised HCU, a whole genome sequencing investigation was performed involving 65 specimens from 15 HCUs across five hospitals to assess if this infection was related to the HCU. Genetic relatedness was found between the 10 HCU M. chimaera isolates from four hospitals. However the M. chimaera isolate from the cardiothoracic patient was not genetically related to the HCU M. chimaera isolates from that hospital, nor to the other HCU isolates, indicating that the HCUs were not the source of the infection in this patient.
Publisher: Elsevier BV
Date: 04-2012
DOI: 10.1016/J.MCP.2012.01.001
Abstract: The recently described phenol-soluble modulin PSM-mec was detected in Staphylococcus aureus, Staphylococcus epidermidis, Staphylococcus fleuretti, Staphylococcus hominis, Staphylococcus pseudintermedius, Staphylococcus saprophyticus, Staphylococcus simulans and Staphylococcus vitulinus from different hosts (humans, goats, dogs, cats, pigs, cattle and turkeys). It was identified in isolates harbouring SCCmec types II, IIA, IIB, IID, III, VIII and in some irregular or truncated elements.
Publisher: Springer Science and Business Media LLC
Date: 26-07-2016
Publisher: Oxford University Press (OUP)
Date: 19-01-2014
DOI: 10.1093/JAC/DKT526
Publisher: Elsevier BV
Date: 09-1998
DOI: 10.1016/S0195-6701(98)90027-5
Abstract: Methicillin aztreonam mannitol salt agar is a sensitive and reliable solid screening medium for detecting methicillin-resistant Staphylococcus aureus (MRSA). With this medium an incubation period of only 20 h is sufficient to either produce visible colonies of MRSA or to exclude MRSA (no staphylococcal colonies). Coagulase testing (requiring a further 6 h) enables coagulase-positive isolates to be provisionally reported as 'possible MRSA' 26-30 h after the swabs were collected. The medium supports growth of intrinsically resistant staphylococci including low-expression-class MRSA (methicillin minimum inhibitory concentration (MIC) 8-16 mg/L), but methicillin susceptible staphylococci and beta-lactamase hyperproducers are suppressed.
Publisher: Elsevier BV
Date: 12-2009
DOI: 10.1071/HI09023
Publisher: Oxford University Press (OUP)
Date: 27-08-2009
DOI: 10.1093/JAC/DKP285
Publisher: Springer Science and Business Media LLC
Date: 03-03-2014
Publisher: Elsevier BV
Date: 08-2010
DOI: 10.1016/J.DIAGMICROBIO.2010.03.015
Abstract: We designed a single-step, closed-tube, real-time polymerase chain reaction and high-resolution melting assay to simultaneously detect the presence of the Panton-Valentine leukocidin gene and discriminate histidine and arginine isoforms. Of 223 Staphylococcus aureus isolates from northern Australia, isoforms clustered by clonal complex (CC). All CC93 isolates harbored the arginine isoform.
Publisher: Oxford University Press (OUP)
Date: 18-11-2015
DOI: 10.1093/JAC/DKU454
Abstract: To describe a family of conjugative plasmids isolated from colonizing community Staphylococcus aureus and determine their ability to mobilize unrelated antimicrobial resistance/virulence plasmids, not encoding mobilization functions. Plasmid pWBG749 was labelled with Tn551 (pWBG749e) to enable laboratory manipulation. Plasmid pWBG749e was conjugated into S. aureus of seven different lineages that harboured unrelated plasmids and mobilization experiments were performed. Plasmids were screened by EcoRI restriction and hybridization with probes prepared from unique pWBG749 conjugation genes. Conjugative plasmids pWBG745, pWBG748 and pWBG749 belong to the same conjugative-plasmid family as the vancomycin resistance plasmid pBRZ01. Plasmid pWBG749e mobilized five unrelated plasmids. Mobilized plasmid pWBG744 is a pIB485-family plasmid that was also found in international S. aureus. Plasmid pWBG749e can mobilize unrelated S. aureus plasmids whose means of dissemination have not previously been understood.
Publisher: Public Library of Science (PLoS)
Date: 10-11-2011
Publisher: Elsevier BV
Date: 2001
DOI: 10.1080/00313020120083223
Abstract: The detection of Helicobacter pylori antigen directly in faecal specimens may offer an alternative non-invasive method for determining the presence of H. pylori infection. This study compared the performance of the Premier Platinum HpSA enzyme immunoassay (HpSA) with histology and CLOtest, a rapid urease test. Of 134 patients undergoing upper gastrointestinal endoscopy, 37 (28%) were H. pylori-positive by histology and CLOtest. Using the HpSA test, H. pylori was detected in 35 H. pylori-positive patients (95% sensitivity) and one H. pylori-negative patient (99% specificity). The positive and negative predictive values for HpSA were 97 and 98%, respectively. HpSA is a rapid, easily performed, non-invasive method for detecting H. pylori.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.JHIN.2015.10.023
Abstract: Two meticillin-resistant Staphylococcus aureus (MRSA) clones, sequence type (ST) 22 and ST239, have successfully spread globally. Across Australia, ST22 has supplanted ST239 as the main healthcare-associated MRSA. To understand the reasons underlying this shift, the epidemiology and clinical features of infections due to ST22 and ST239 MRSA isolates from a tertiary hospital in Melbourne, Australia were compared. Over six months, consecutive MRSA isolates with clinical data were collected from specimens referred to Alfred Health Pathology (AHP). Isolates were genotyped by a multi-locus-sequence-typing-based high-resolution melting method. Three hundred and twenty-eight of 1079 (30%) S. aureus isolated by AHP were MRSA. Of these, 313 were genotyped 78 (25%) were clonal complex (CC) 22 (representing ST22) and 142 (45%) were CC239 (representing ST239). Common clinical syndromes included skin or soft tissue, respiratory tract and osteo-articular infections. On multi-variate logistic regression, compared with CC239, CC22 was associated with older patients [adjusted odds ratio (aOR) 1.04 for each year increase, 95% confidence interval (CI) 1.02-1.07)], and patients from subacute hospitals (aOR 2.7, 95% CI 1.2-5.8) or long-term care facilities (LTCFs aOR 5.5, 95% CI 2.0-14.5). Median time from patient admission to MRSA isolation was nine days for CC239 and one day for CC22 (P < 0.01). MRSA strain epidemiology varied according to hospital unit. CC22 and CC239 MRSA have differing ecological niches. CC22 is associated with elderly patients in LTCFs, and CC239 is associated with nosocomial acquisition. Infection control strategies involving LTCFs and their residents will likely be required to achieve continued MRSA control.
Publisher: Public Library of Science (PLoS)
Date: 14-02-2020
Publisher: American Society for Microbiology
Date: 26-12-2018
Abstract: Staphylococcus pseudintermedius is a significant veterinary pathogen and occasional cause of infections in humans. β-Lactams are an important group of antimicrobials used to treat staphylococcal infections in humans and animals. However, when staphylococci become methicillin resistant via the acquisition of a mobile genetic element called staphylococcal cassette chromosome mec (SCC mec ), they become resistant to all β-lactams. This study detected a novel SCC mec element among a cluster of methicillin-resistant S. pseudintermedius isolates from animals in Australia. It also detected SCC mec elements in S. pseudintermedius that had high similarity to those identified in methicillin-resistant Staphylococcus aureus , demonstrating how human and animal pathogens can share the same resistance determinants.
Publisher: Oxford University Press (OUP)
Date: 31-05-2011
DOI: 10.1093/CID/CIR250
Publisher: Australian Government Department of Health
Date: 16-03-2020
Abstract: From 1 January to 31 December 2018, thirty-six institutions around Australia participated in the Australian Enterococcal Sepsis Outcome Programme (AESOP). The aim of AESOP 2018 was to determine the proportion of enterococcal bacteraemia isolates in Australia that were antimicrobial resistant, and to characterise the molecular epidemiology of the E. faecium isolates. Of the 1,248 unique episodes of bacteraemia investigated, 93.5% were caused by either E. faecalis (54.2%) or E. faecium (39.3%). Ampicillin resistance was not detected in E. faecalis but was detected in 89.4% of E. faecium. Vancomycin non-susceptibility was not detected in E. faecalis but was reported in 45.0% of E. faecium. Overall 49.3% of E. faecium isolates harboured vanA or vanB genes. Of the vanA/vanB positive E. faecium isolates, 52.9% harboured vanA genes and 46.2% vanB genes 0.8% harboured both vanA and vanB genes. The percentage of E. faecium bacteraemia isolates resistant to vancomycin in Australia is substantially higher than that seen in most European countries. E. faecium consisted of 59 multilocus sequence types (STs) of which 74.4% of isolates were classified into six major STs containing ten or more isolates. All major STs belong to clonal cluster (CC) 17, a major hospital-adapted polyclonal E. faecium cluster. The predominant STs (ST17, ST1424, ST796, ST80, ST1421, and ST262) were found across most regions of Australia. The most predominant clone was ST17 which was identified in all regions except the Australian Capital Territory and the Northern Territory. Overall, 55.8% of isolates belonging to the six predominant STs harboured vanA or vanB genes. The AESOP 2018 study has shown that enterococcal bacteraemias in Australia are frequently caused by polyclonal icillin-resistant high-level gentamicin-resistant vanA- or vanB-harbouring E. faecium which have limited treatment options.
Publisher: Springer Science and Business Media LLC
Date: 06-2013
DOI: 10.1038/NPHYS2615
Publisher: Australian Government Department of Health
Date: 16-03-2020
Abstract: From 1 January to 31 December 2018, thirty-six institutions around Australia participated in the Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP). The aim of ASSOP 2018 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to methicillin, and to characterise the molecular epidemiology of the methicillin-resistant isolates. A total of 2,673 S. aureus bacteraemia episodes were reported, of which 78.9% were community-onset. A total of 17.4% of S. aureus isolates were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 17.1% which was not significantly higher than the 13.6% mortality associated with methicillin-susceptible SAB (p = 0.1). With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However in addition to the β-lactams approximately 42% of methicillin-resistant S. aureus (MRSA) were resistant to erythromycin, 36% to ciprofloxacin and approximately 13% resistant to co-trimoxazole, tetracycline and gentamicin. When applying the EUCAST breakpoints teicoplanin resistance was detected in two S. aureus isolates. Resistance was not detected for vancomycin and linezolid. Resistance to non-beta-lactam antimicrobials was largely attributable to two healthcare-associated MRSA clones: ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA). The ST22-IV [2B] (EMRSA-15) clone is the predominant healthcare-associated clone in Australia. Seventy-eight percent of methicillin-resistant SAB episodes in 2018 were due to community-associated clones. Although polyclonal, approximately 76.3% of community-associated clones were characterised as ST93-IV [2B] (Queensland CA-MRSA), ST5-IV [2B], ST45-VT [5C2& ], ST1-IV [2B], ST30-IV [2B], ST78-IV [2B] and ST97-IV [2B]. Community-associated MRSA, in particular the ST45-VT [5C2& ] clone, has acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. The ST45-VT [5C2& ] clone accounted for 11.7% of CA-MRSA. As CA-MRSA is well established in the Australian community, it is important that antimicrobial resistance patterns in community- and healthcare-associated SAB are monitored, as this information will guide therapeutic practices in treating S. aureus sepsis.
Publisher: Springer Science and Business Media LLC
Date: 03-03-2012
DOI: 10.1007/S10096-012-1585-Y
Abstract: To determine the impact of infectious diseases consultation (IDC) in Staphylococcus aureus bacteraemia. All MRSA bacteraemia and a random subset of MSSA bacteraemia were retrospectively analysed. Out of 599 SAB episodes, 162 (27%) were followed by an IDC. Patients with IDC were younger and more frequently intravenous drug users, but fewer resided in a long-term care facility or were indigenous. Hospital length of stay was longer (29.5 vs 17 days, p < 0.001), and endocarditis (19.1% vs 7.3%, p < 0.001) and metastatic seeding (22.2% vs 10.1%, p < 0.001) were more frequent in the IDC group however, SAPS II scores were lower in the IDC group (27 vs 37, p < 0.001). ICU admission rates in the two groups were similar. The isolate tested susceptible to empirical therapy more frequently in the IDC group (88.9% vs 78.0%, p = 0.003). Seven-day (3.1 vs 16.5%), 30-day (8.0% vs 27.0%) and 1-year mortality (22.2% vs 44.9%) were all lower in the IDC group (all p < 0.001). Multivariate analysis showed that effective initial therapy was the only variable associated with the protective effect of IDC. In patients with SAB, all-cause mortality was significantly lower in patients who had an IDC, because of the higher proportion of patients receiving effective initial antibiotics.
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.IJANTIMICAG.2016.01.008
Abstract: A total of 9599 isolates of Gram-negative bacteria (GNB) causing urinary tract infections (UTIs) were collected from 60 centres in 13 countries in the Asia-Pacific region from 2010-2013. These isolates comprised Enterobacteriaceae species (mainly Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Klebsiella oxytoca, Enterobacter cloacae and Morganella morganii) and non-fermentative GNB species (predominantly Pseudomonas aeruginosa and Acinetobacter baumannii). In vitro susceptibilities were determined by the agar dilution method and susceptibility profiles were determined using the minimum inhibitory concentration (MIC) interpretive breakpoints recommended by the Clinical and Laboratory Standards Institute in 2015. Production of extended-spectrum β-lactamases (ESBLs) amongst E. coli, K. pneumoniae, P. mirabilis and K. oxytoca isolates was determined by the double-disk synergy test. China, Vietnam, India, Thailand and the Philippines had the highest rates of GNB species producing ESBLs and the highest rates of cephalosporin resistance. ESBL production and hospital-acquired infection (isolates obtained ≥48 h after admission) significantly compromised the susceptibility of isolates of E. coli and K. pneumoniae to ciprofloxacin, levofloxacin and most β-lactams, with the exception of imipenem and ertapenem. However, >87% of ESBL-producing E. coli strains were susceptible to amikacin and piperacillin/tazobactam, indicating that these antibiotics might be appropriate alternatives for treating UTIs due to ESBL-producing E. coli. Fluoroquinolones were shown to be inappropriate as empirical therapy for UTIs. Antibiotic resistance is a serious problem in the Asia-Pacific region. Therefore, continuous monitoring of evolutionary trends in the susceptibility profiles of GNB causing UTIs in Asia is crucial.
Publisher: Elsevier BV
Date: 09-2020
Publisher: Cold Spring Harbor Laboratory
Date: 08-01-2013
Abstract: The widespread use of antibiotics in association with high-density clinical care has driven the emergence of drug-resistant bacteria that are adapted to thrive in hospitalized patients. Of particular concern are globally disseminated methicillin-resistant Staphylococcus aureus (MRSA) clones that cause outbreaks and epidemics associated with health care. The most rapidly spreading and tenacious health-care-associated clone in Europe currently is EMRSA-15, which was first detected in the UK in the early 1990s and subsequently spread throughout Europe and beyond. Using phylogenomic methods to analyze the genome sequences for 193 S. aureus isolates, we were able to show that the current pandemic population of EMRSA-15 descends from a health-care-associated MRSA epidemic that spread throughout England in the 1980s, which had itself previously emerged from a primarily community-associated methicillin-sensitive population. The emergence of fluoroquinolone resistance in this EMRSA-15 subclone in the English Midlands during the mid-1980s appears to have played a key role in triggering pandemic spread, and occurred shortly after the first clinical trials of this drug. Genome-based coalescence analysis estimated that the population of this subclone over the last 20 yr has grown four times faster than its progenitor. Using comparative genomic analysis we identified the molecular genetic basis of 99.8% of the antimicrobial resistance phenotypes of the isolates, highlighting the potential of pathogen genome sequencing as a diagnostic tool. We document the genetic changes associated with adaptation to the hospital environment and with increasing drug resistance over time, and how MRSA evolution likely has been influenced by country-specific drug use regimens.
Publisher: American Society for Microbiology
Date: 07-03-2018
Abstract: The USA300 North American epidemic (USA300-NAE) clone of methicillin-resistant Staphylococcus aureus has caused a wave of severe skin and soft tissue infections in the United States since it emerged in the early 2000s, but its geographic origin is obscure. Here we use the population genomic signatures expected from the serial founder effects of a geographic range expansion to infer the origin of USA300-NAE and identify polymorphisms associated with its spread. Genome sequences from 357 isolates from 22 U.S. states and territories and seven other countries are compared. We observe two significant signatures of range expansion, including decreases in genetic ersity and increases in derived allele frequency with geographic distance from the Pennsylvania region. These signatures account for approximately half of the core nucleotide variation of this clone, occur genome wide, and are robust to heterogeneity in temporal s ling of isolates, human population density, and recombination detection methods. The potential for positive selection of a gyrA fluoroquinolone resistance allele and several intergenic regions, along with a 2.4 times higher recombination rate in a resistant subclade, is noted. These results are the first to show a pattern of genetic variation that is consistent with a range expansion of an epidemic bacterial clone, and they highlight a rarely considered but potentially common mechanism by which genetic drift may profoundly influence bacterial genetic variation. IMPORTANCE The process of geographic spread of an origin population by a series of smaller populations can result in distinctive patterns of genetic variation. We detect these patterns for the first time with an epidemic bacterial clone and use them to uncover the clone’s geographic origin and variants associated with its spread. We study the USA300 clone of methicillin-resistant Staphylococcus aureus , which was first noticed in the early 2000s and subsequently became the leading cause of skin and soft tissue infections in the United States. The eastern United States is the most likely origin of epidemic USA300. Relatively few variants, which include an antibiotic resistance mutation, have persisted during this clone’s spread. Our study suggests that an early chapter in the genetic history of this epidemic bacterial clone was greatly influenced by random subs ling of isolates during the clone’s geographic spread.
Publisher: Elsevier BV
Date: 2001
Publisher: Cambridge University Press (CUP)
Date: 09-2008
DOI: 10.1086/590260
Abstract: To describe an outbreak of invasive methicillin-resistant Staphylococcus aureus (MRSA) infection after percutaneous needle procedures (acupuncture and joint injection) performed by a single medical practitioner. A medical practitioner's office and 4 hospitals in Perth, Western Australia. Eight in iduals who developed invasive MRSA infection after acupuncture or joint injection performed by the medical practitioner. We performed a prospective and retrospective outbreak investigation, including MRSA colonization surveillance, environmental s ling for MRSA, and detailed molecular typing of MRSA isolates. We performed an infection control audit of the medical practitioner's premises and practices and administered MRSA decolonization therapy to the medical practitioner. Eight cases of invasive MRSA infection were identified. Seven cases occurred as a cluster in May 2004 another case (identified retrospectively) occurred approximately 15 months earlier in February 2003. The primary sites of infection were the neck, shoulder, lower back, and hip: 5 patients had septic arthritis and bursitis, and 3 had pyomyositis 3 patients had bacteremia, including 1 patient with possible endocarditis. The medical practitioner was found to be colonized with the same MRSA clone [ST22-MRSA-IV (EMRSA-15)] at 2 time points: shortly after the first case of infection in March 2003 and again in May 2004. After the medical practitioner's premises and practices were audited and he himself received MRSA decolonization therapy, no further cases were identified. This outbreak most likely resulted from a breakdown in sterile technique during percutaneous needle procedures, resulting in the transmission of MRSA from the medical practitioner to the patients. This report demonstrates the importance of surveillance and molecular typing in the identification and control of outbreaks of MRSA infection.
Publisher: Frontiers Media SA
Date: 09-07-2018
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 10-2005
Abstract: Methicillin-resistant Staphylococcus aureus (MRSA) continues to be a notable cause of hospital-acquired infections. A statewide screening and control policy was implemented in Western Australia (WA) after an outbreak of epidemic MRSA in a Perth hospital in 1982. We report on statutory notifications from 1998 to 2002 and review the 20-year period from 1983 to 2002. The rate of reporting of community-associated Western Australia MRSA (WAMRSA) escalated from 1998 to 2002 but may have peaked in 2001. Several outbreaks were halted, but they resulted in an increase in reports as a result of screening. A notable increase in ciprofloxacin resistance during the study period was observed as a result of more United Kingdom epidemic MRSA (EMRSA) -15 and -16. WA has seen a persistently low incidence of multidrug-resistant MRSA because of the screening and decolonization program. Non-multidrug-resistant, community-associated WAMRSA strains have not established in WA hospitals.
Publisher: Oxford University Press (OUP)
Date: 04-02-2020
DOI: 10.1093/JAC/DKZ560
Abstract: Early identification of MRSA by diagnostic medical microbiology laboratories enables improved antimicrobial choice and outcomes. The Cepheid Xpert® MRSA/SA BC test rapidly identifies Staphylococcus aureus bloodstream infections through spa gene detection and methicillin resistance via mecA gene detection. Recent emergence of S. aureus with deletions in the spa gene has resulted in false-negative results for this test, leading to misidentification of infections with this organism, particularly MRSA ST45. To investigate the emergence and prevalence of ST45 MRSA in New South Wales (NSW), Australia. WGS read data from six NSW hospitals were collected for 131 ST45 MRSA isolates and analysed. Of the 131 ST45 MRSA investigated, 88.5% (116/131) contained a deletion in the spa gene that appeared to have arisen once in approximately 2010 followed by clonal expansion. Given the successful establishment of this ‘spa-deletion’ MRSA clone, the Cepheid Xpert® MRSA/SA BC test became unreliable for confirming S. aureus bacteraemia in NSW. Subsequently, the algorithm used by this test has been updated and evaluated to take into account the presence of S. aureus with either a spa deletion or SCCmec target variations. This study highlighted the applied use of WGS for assessing diagnostic assays and informing necessary changes to ensure the viability of the Cepheid Xpert® MRSA/SA BC test in the context of the new ‘spa-deletion’ MRSA clone. It demonstrated how continued surveillance through WGS can reveal evolutionary events that may impact diagnostic assays, allowing corrective modifications to be made in real time.
Publisher: Wiley
Date: 31-05-2002
DOI: 10.1046/J.1523-5378.2002.00078.X
Abstract: Identification of the immunoreactive proteins of Helicobacter pylori is important for the development of both diagnostic tests and vaccines relating to the organism. Our aim was to determine whether there are significant differences between human IgG and IgA reactivities to in idual H. pylori proteins, and whether patterns of immunoreactivity are sustained across different strains of H. pylori. The total complement of protein from seven strains of H. pylori was resolved by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE). Proteins were transferred electrophoretically onto polyvinylene difluoride (PVDF) membranes, which were probed with sera pooled either from H. pylori-infected patients, or noninfected (control) patients. Highly immunoreactive proteins were detected using chromogenic enzyme-antibody conjugates recognising either serum IgG or IgA. These proteins were then characterised by tryptic peptide-mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Highly immunoreactive proteins were detected which were common to all seven strains, and recognised by both immunoglobulin subclasses. The proteins appear to be localised in five groups. Protein analysis established that these groups encompass multiple isoforms of chaperonin HspB (two subgroups) urease beta-subunit UreB elongation factor EF-Tu and flagellin FlaA. The pattern of highly immunoreactive proteins was strongly conserved across the seven strains. These results suggest that within a tightly defined region on the H. pylori proteome map there are five groups of proteins that are highly reactive to both IgG and IgA. Our analysis suggests it is unlikely that the highly immunoreactive clusters harbour any significant proteins other than isoforms of HspB, UreB, EF-Tu and FlaA, and that, with the partial exception of FlaA, these clusters are strongly conserved across all seven strains.
Publisher: American Society for Microbiology
Date: 11-2002
DOI: 10.1128/JCM.40.11.4289-4294.2002
Abstract: Multiple methicillin-resistant Staphylococcus aureus (MRSA) clones carrying type IV staphylococcal cassette chromosome mec were identified in the community-acquired MRSA strains of both the United States and Australia. They multiplied much faster than health-care-associated MRSA and were resistant to fewer non-beta-lactam antibiotics. They seem to have been derived from more erse S. aureus populations than health-care-associated MRSA strains.
Publisher: Springer Science and Business Media LLC
Date: 13-07-2017
DOI: 10.1038/S41598-017-04789-0
Abstract: Pigs have been recognised as a reservoir of livestock associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in Europe, Asia and North America. However, little is known about the presence and distribution of MRSA in the Australian pig population and pig industry. This study describes the presence, distribution and molecular characteristics of the human adapted Australian CA-MRSA ST93 isolated from pigs, people, and the environment within a piggery. Isolates were subjected to antibiotic susceptibility testing, DNA microarray, whole genome sequencing, multi locus sequence typing, virulence and resistance gene characterization and phylogenetic analysis. MRSA were isolated from 60% (n = 52) of farm workers where 84% of isolates returned ST93 and the rest ST398. Of the thirty-one pig isolates tested further, an equal number of ST398 and ST93 (15 each) and one as ST30-V were identified. Four of six environmental isolates were identified as ST93 and two as ST398. This study has identified for the first time in Australia the occurrence of CA-MRSA ST93 and LA-MRSA ST398 amongst farm workers, pigs, and the farm environment. Comparative genome analysis indicates that ST398 is likely to have been introduced into Australia from Europe or North America. This study also reports the first linezolid resistant MRSA isolated in Australia.
Publisher: AMPCo
Date: 06-2001
Publisher: Elsevier BV
Date: 04-2023
Publisher: American Society for Microbiology
Date: 07-2004
DOI: 10.1128/JCM.42.7.3185-3190.2004
Abstract: Community methicillin-resistant Staphylococcus aureus (CMRSA) strains are being isolated with increasing frequency around the world. In Western Australia CMRSA are endemic in geographically remote communities and have been found to belong to five different contour-cl ed homogeneous electric field (CHEF) electrophoretic patterns. Representatives of each of these CHEF patterns have been compared to CMRSA representative of CHEF patterns from other Australian states and New Zealand. With one exception, all of the isolates were nonmultiresistant and were not resistant to many antimicrobial agents other than the β-lactams. With one exception, which is not believed to be a CMRSA, all of the isolates harbored a β-lactamase plasmid. Erythromycin resistance was associated with a 2-kb plasmid. One of the β-lactamase plasmids was found to be able to acquire additional resistance determinants to become a multiple resistance plasmid. There were 10 multilocus sequence types belonging to eight distantly related clonal complexes of S. aureus . One new sequence type was found. Although most of the CMRSA harbored the type IVa SCC mec , a type IV structural variant was found and two new SCC mec types were identified. Protein A gene ( spa ) typing revealed two new spa types and, with two exceptions, corresponded to multilocus sequence typing. In contrast to other reports on CMRSA, most of the CMRSA strains studied here did not contain the Panton-Valentine leukocidin genes. The results also demonstrate that nonmultiresistant hospital strains such as UK EMRSA-15 may be able to circulate in the community and could be mistaken for CMRSA based on their resistance profiles.
Publisher: Springer Science and Business Media LLC
Date: 05-06-2021
DOI: 10.1186/S12864-021-07738-4
Abstract: The global emergence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has seen the dominance of specific clones in different regions around the world with the PVL-positive ST93-IV as the predominant CA-MRSA clone in Australia. In this study we applied a genome-wide association study (GWAS) approach on a collection of Australian ST93-IV MRSA genomes to screen for genetic traits that might have assisted the ongoing transmission of ST93-IV in Australia. We also compared the genomes of ST93-IV bacteraemia and non-bacteraemia isolates to search for potential virulence genes associated with bacteraemia. Based on single nucleotide polymorphism phylogenetics we revealed two distinct ST93-IV clades circulating concurrently in Australia. One of the clades contained isolates primarily isolated in the northern regions of Australia whilst isolates in the second clade were distributed across the country. Analyses of the ST93-IV genome plasticity over a 15-year period (2002–2017) revealed an observed gain in accessory genes amongst the clone’s population. GWAS analysis on the bacteraemia isolates identified two gene candidates that have previously been associated to this kind of infection. Although this hypothesis was not tested here, it is possible that the emergence of a ST93-IV clade containing additional virulence genes might be related to the high prevalence of ST93-IV infections amongst the indigenous population living in the northern regions of Australia. More importantly, our data also demonstrated that GWAS can reveal candidate genes for further investigations on the pathogenesis and evolution of MRSA strains within a same lineage.
Publisher: Elsevier BV
Date: 08-2009
DOI: 10.1111/J.1469-0691.2009.02792.X
Abstract: Between 2003 and 2008, 76 clinical isolates of the Panton-Valentine leukocidin-positive Staphylococcus aureus strain 'West Australian methicillin-resistant Staphylococcus aureus (MRSA)-12' (WA MRSA-12) were recovered from 72 patients living in the Perth area in Western Australia. These isolates were found to belong to multilocus sequence type 8, and had a USA300-like pulsed-field gel electrophoresis pulsotype. All isolates were genotyped using diagnostic DNA arrays covering species markers, resistance factors, virulence-associated, as well as MSCRAMM (microbial surface components recognizing adhesive matrix molecules) genes to prove the identity between WA MRSA-12 and the pandemic strain USA300, as well as to detect possible genetic variability. In general, WA MRSA-12 isolates were similar to USA300, and the most common variant was identical to USA300-TC1516. From this clone, most of the other variants may have evolved by a limited number of gene losses or acquisitions. Variations in carriage of virulence and resistance-associated genes allow distinction of variants or sub-clones. Altogether, 16 variants could be distinguished. They differed in the carriage of resistance genes (blaZ/I/R, ermC, msrA + mpbBM, aadD + mupR, aphA3 + sat, tetK, qacC, merA/B/R/T) of beta-haemolysin-converting phages and of enterotoxins (sek + seq, which were deleted in four isolates). Notably, the arginine catabolic mobile element (ACME) was absent in 12 isolates (15.8%). The mercury resistance (mer) operon, which is usually associated with SCCmec type III elements, was found in several ACME-negative isolates. The present study emphasises the importance of genotyping in detecting the introduction and evolution of significant MRSA strains within a community.
Publisher: Springer Science and Business Media LLC
Date: 10-09-2012
DOI: 10.1007/S10096-011-1408-6
Abstract: Due to a longstanding comprehensive "search and destroy policy", methicillin-resistant Staphylococcus aureus (MRSA) is not endemic in Western Australian (WA) acute care hospitals. As the prevalence of MRSA in the community has increased, healthcare workers (HCW) are at risk of importing MRSA into hospitals. We aimed to determine the prevalence of and risk factors for nasal MRSA colonization in our HCW population. A period prevalence study was conducted at an 850-bed tertiary hospital. Basic demographics and a nasal swab were obtained. A total of 1,542 HCWs employed in our centre were screened for MRSA, of whom 3.4% (n = 52) were colonized. MRSA colonization was more common in patient care assistants (6.8%) and nurses (5.2%) than in allied health professionals (1.7%) and doctors (0.7%) (p < 0.01). Working in "high-risk" wards that cared for MRSA colonized/infected patients was the strongest risk factor for HCW MRSA colonization (p < 0.001). ST1-IV and ST78-IV (the most common community clones in the region) were the most frequently identified clones. In conclusion, MRSA colonization of HCWs occurs primarily in HCWs caring for patients colonized or infected with MRSA. Surveillance screening of HCWs should be regularly performed on wards with patients with high MRSA colonization prevalence to prevent further spread in the hospital.
Publisher: American Society for Microbiology
Date: 12-2005
DOI: 10.1128/AAC.49.12.5129-5132.2005
Abstract: Twenty Australian community staphylococci harboring the type V staphylococcal cassette chromosome mec (SCC mec ) were found to belong to eight multilocus sequence types. Five were previously unreported novel type V SCC mec elements. The mec complexes were of two types, based on the polymorphisms in the IS 431 transposase genes. Five isolates were multiresistant.
Publisher: Oxford University Press (OUP)
Date: 12-07-2021
Abstract: Amoxicillin plus ceftriaxone combination therapy is now standard of care for enterococcal endocarditis. Due to amoxicillin instability in infusion devices, benzylpenicillin plus ceftriaxone may be substituted to facilitate outpatient parenteral antimicrobial therapy (OPAT) delivery, despite lack of guideline endorsement. To assess the clinical efficacy of benzylpenicillin plus ceftriaxone for the management of enterococcal endovascular infections, in addition to assessing this combination’s in vitro synergy. Retrospective cohort study assessing unplanned readmissions, relapses and mortality for 20 patients with endovascular Enterococcus faecalis infections treated with benzylpenicillin plus ceftriaxone delivered via OPAT. For a subset of isolates, synergism for both amoxicillin and benzylpenicillin in combination with ceftriaxone was calculated using a chequerboard method. Patients had endovascular infections of native cardiac valves (n = 11), mechanical or bioprosthetic cardiac valves (n = 7), pacemaker leads (n = 1) or left ventricular assistant devices (n = 1). The median duration of OPAT was 22 days, and the most frequent antimicrobial regimen was benzylpenicillin 14 g/day via continuous infusion and ceftriaxone 4 g once daily via short infusion. Rates of unplanned readmissions were high (30%), although rates of relapsed bacteraemia (5%) and 1 year mortality (15%) were comparable to the published literature. Benzylpenicillin less frequently displayed a synergistic interaction with ceftriaxone when compared with amoxicillin (3 versus 4 out of 6 isolates). Lower rates of synergistic antimicrobial interaction and a significant proportion of unplanned readmissions suggest clinicians should exercise caution when treating enterococcal endovascular infection utilizing a combination of benzylpenicillin and ceftriaxone via OPAT.
Publisher: American Society for Microbiology
Date: 27-04-2021
DOI: 10.1128/AEM.03037-20
Abstract: Resistance to the critically important antimicrobials vancomycin, teicoplanin, and linezolid is not found in enterococci collected from Australian finisher pigs. However, some antimicrobial resistance was observed.
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.IJANTIMICAG.2019.02.009
Abstract: The first outbreak of vancomycin-resistant Enterococcus faecium (VREfm) in Western Australia was recorded in 2001. A state-wide infection control effort that oversaw patient screening and transfers successfully terminated the outbreak within six months however, the outbreak re-emerged two years later. Over the two outbreaks, the vanB-positive multilocus sequence type (ST) 173 E. faecium strain was isolated from 201 patients. Our objective was to identify differences in genetic traits leading to successful transmission of ST173 VREfm compared with non-ST173 VREfm isolated during the same period. We also aimed to describe the changes observed in the ST173 VREfm genome collected during the two outbreaks. Virulence factors ecbA, fss3, psaA and scm identified in the non-ST173 isolates were largely absent in the ST173 isolates. The esp gene was not identified beyond 45% coverage for any isolate in this study. In terms of resistance genes, tet(U) was identified in 94.7% of ST173 VREfm isolated in the first outbreak but was largely absent in ST173 VREfm isolated in the second outbreak and in non-ST173 VREfm. Seven ST173 VREfm isolates (Clade A) carried dfrG but not tet(M) resistance genes. The average genome size of ST173 VREfm isolated in the first outbreak was significantly larger than the genome size of ST173 VREfm isolated in the second outbreak. The reduced number of virulence factors in ST173 isolates may explain the low infection and high colonization rates observed during the outbreak. In addition, isolates with larger genomes were found to be associated with outbreaks.
Publisher: American Chemical Society (ACS)
Date: 15-11-2017
DOI: 10.1021/ACS.NANOLETT.7B03372
Abstract: A core process in many quantum tasks is the generation of entanglement. It is being actively studied in a variety of physical settings-from simple bipartite systems to complex multipartite systems. In this work we experimentally study the generation of bipartite entanglement in a nanophotonic system. Entanglement is generated via the quantum interference of two surface plasmon polaritons in a beamsplitter structure, i.e., utilizing the Hong-Ou-Mandel (HOM) effect, and its presence is verified using quantum state tomography. The amount of entanglement is quantified by the concurrence and we find values of up to 0.77 ± 0.04. Verifying entanglement in the output state from HOM interference is a nontrivial task and cannot be inferred from the visibility alone. The techniques we use to verify entanglement could be applied to other types of photonic system and therefore may be useful for the characterization of a range of different nanophotonic quantum devices.
Publisher: Elsevier BV
Date: 2004
DOI: 10.1111/J.1470-9465.2004.T01-1-00844.X
Abstract: We determined the species distribution and in-vitro susceptibility of 6082 bloodstream infection (BSI) isolates of Candida spp. collected from 250 medical centres in 32 nations over a 10-year period from 1992 through 2001. The species included 3401 C. albicans, 984 C. glabrata, 796 C. parapsilosis, 585 C. tropicalis, 153 C. krusei, 67 C. lusitaniae, 48 C. guilliermondii, 10 C. famata, 10 C. kefyr, six C. pelliculosa, five C. rugosa, four C. lipolytica, three C. dubliniensis, three C. inconspicua, two C. sake and one isolate each of C. lambica, C. norvegensis and C. zeylanoides. Minimum inhibitory concentration determinations were made using the National Committee for Clinical Laboratory Standards reference broth microdilution method. Variation in the rank order and frequency of the different species of Candida was observed over time and by geographic area. The proportion of BSI due to C. albicans and C. glabrata increased and C. parapsilosis decreased over time in Canada, the USA and Europe. C. glabrata was an infrequent cause of BSI in Latin America and the Asia-Pacific region. Very little variation in fluconazole susceptibility was observed among isolates of C. albicans, C. tropicalis and C. parapsilosis. These species accounted for 78% of all BSI and remained highly susceptible (91-100% susceptible) to fluconazole from 1992 to 2001 irrespective of geographic origin. The prevalence of fluconazole resistance among C. glabrata isolates was variable both over time and among the various countries and regions. Resistance to fluconazole among C. glabrata isolates was greatest in the USA and varied by US census region (range 0-23%). These observations are generally encouraging relative to the sustained usefulness of fluconazole as a systemically active antifungal agent for the treatment of candida BSI.
Publisher: Cambridge University Press (CUP)
Date: 14-02-2014
DOI: 10.1017/S0950268814000053
Abstract: Our aim was to describe the epidemiology and incidence of community-onset invasive S. aureus disease in children presenting to our hospital, and to compare the clonal complexes and virulence genes of S. aureus strains causing invasive and non-invasive disease. The virulence gene repertoire of invasive disease isolates was characterized using DNA microarray and compared with the virulence gene repertoire of non-invasive S. aureus isolates. Over the study period, 163 children had an invasive S. aureus infection. There was no difference in the distribution of clonal complexes or in the prevalence of genes encoding virulence factors between invasive and non-invasive isolates. Future research should include a strong focus on identifying the host and environmental factors that, along with organism virulence factors, are contributing to the patterns of invasive S. aureus disease observed in New Zealand.
Publisher: Mary Ann Liebert Inc
Date: 06-2004
Abstract: During 1996, 4065 consecutive Staphylococcus aureus strains from different patients were collected in 21 worldwide hospital laboratories. The strains, their resistance pattern, and hospital demographic data were forwarded to Statens Serum Institut where the strains were typed and data analyzed. Resistance patterns varied by region and resistance to other antibiotics than methicillin were mainly related to the occurrence of methicillin resistance, except for mupirocin, rif icin, and fusidic acid. Methicillin-resistant S. aureus (MRSA) occurred with low levels in hospitals in Northern Europe (<1%), increasing levels in middle-European countries, United States, New Zealand, and Australia (6-22%), and very high levels in Southern European countries as well as in parts of the United States, Asia, and South Africa (28-63%). MRSA found in large hospitals were more resistant to other antibiotics than MRSA found in smaller hospitals serviced by the same laboratory. No difference in resistance levels was seen for methicillin-susceptible S. aureus (MSSA) isolated in large or small hospitals. Intensive Care Units had the highest level of MRSA. Strains from the lower respiratory tract showed the highest resistance levels and blood isolates the lowest. A dominating MRSA clone was found in hospitals with an MRSA frequency of more than 10%. Pulsed-field gel electrophoresis (PFGE) typing recognized several of these clones as international epidemic MRSA (E-MRSA). All MSSA isolates were phage typed (typeability 85.4%) and ided in seven major phage patterns. Isolates of all patterns were found in all hospitals except one, indicating that the MSSA seldom represented the spread of clones within the hospital. The comparison should evaluate the prevalence of community-acquired MRSA and identify internationally E-MRSA. The present study gives a snapshot of the MRSA situation, but it is important to build up a continuous national and international surveillance, because MRSA is a global socioeconomic problem. Global infection control procedures, including rational antibiotic use, should be agreed on. The accompanying paper will address the issue of antibiotic consumption and MRSA.
Publisher: Cambridge University Press (CUP)
Date: 2020
DOI: 10.1017/S0950268820000849
Abstract: This study presents enhanced surveillance data from 2004 to 2018 for all community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) specimens collected in Western Australia (WA), and describes the changing epidemiology over this period. A total of 57 557 cases were reviewed. Annual incidence rates increased from 86.2 cases per 100 000 population to 245.6 per 100 000 population (IRR = 2.9, CI 95 2.7–3.0). The proportion of isolates carrying Panton–Valentine leucocidin (PVL)-associated genes increased from 3.4% to 59.8% ( χ 2 test for trend 7021.9, P 0.001). The emergence of PVL-positive, ‘Queensland CA-MRSA’ (ST93-IV) and ‘WA 121’ (ST5-IV) accounted for the majority of increases in CA-MRSA across the study period. It is unclear why some clones are more prolific in certain regions. In WA, CA-MRSA rates increase as indices of temperature and humidity increase after controlling for socioeconomic disadvantage. We suggest climatic conditions may contribute to transmission, along with other socio-behavioural factors. A better understanding of the ability for certain clones to form ecological niches and cause outbreaks is required.
Publisher: American Society for Microbiology
Date: 11-2015
DOI: 10.1128/AAC.01745-15
Abstract: A West Australian methicillin-resistant Staphylococcus aureus strain (WA MRSA-59) was characterized by microarray and sequencing. Its pseudo-staphylococcal cassette chromosome mec (SCC mec ) element comprised dcs , Q9XB68 - dcs , mvaS -SCC, Q5HJW6 , dru , ugpQ , ydeM , mecA-mecR-mecI , txbi mecI , tnp IS 431 , copA2-mco (copper resistance), ydhK , arsC-arsB-arsR (arsenic resistance), open reading frame PT43, and per-2 . Recombinase genes, xylR ( mecR2 ), and PSM- mec (phenol-soluble modulin) were absent. We suggest that mec complex A should be split into two subtypes. One harbors PSM- mec and xylR ( mecR2 ). It is found in SCC mec types II, III, and VIII. The second subtype, described herein, is present in WA MRSA-59 and some coagulase-negative staphylococci.
Publisher: Wiley
Date: 02-1998
DOI: 10.1111/J.1445-5994.1998.TB04452.X
Abstract: Limited Australian data are available on either short duration therapy for Helicobacter pylori infection, or the impact of metronidazole resistance on the outcome of treatment. To compare the efficacy of two treatment regimens and determine the influence metronidazole resistance has on clearing H. pylori infection. Eighty patients with H. pylori infection proven at upper gastrointestinal endoscopy, none of whom had previously received therapy for H. pylori, were randomised to one week therapy with either bismuth subcitrate one tablet qid, tetracycline 500 mg qid and metronidazole 400 mg tds (BTM), or lansoprazole 30 mg bd, amoxycillin 500 mg qid and metronidazole 400 mg tds (LAM). Effectiveness of therapy was measured by C14-urea breath test at six weeks. On an intention-to-treat basis, clearance of infection was achieved in 17 of 32 (53% 95% CI: 35-71%) evaluable patients receiving BTM and 32 of 46 (70%, 54-82%) patients receiving LAM (p = 0.16). Metronidazole resistance was found in 32 of 65 (49%) patients in whom H. pylori was isolated by culture. On a per-protocol basis, of patients who had metronidazole sensitive strains of H. pylori 23 of 24 (96%) cleared infection after therapy with either BTM or LAM, compared with 14 of 24 (58%) who were metronidazole resistant (p = 0.004). Clarithromycin resistance was not found in 45 patients tested. In Western Australia clearance rates of H. pylori infection, after one week of BTM or LAM, are lower than in other published series. The high incidence of metronidazole resistance is the main determinant of our relatively poor eradication rates.
Publisher: Springer Science and Business Media LLC
Date: 10-02-2014
Publisher: Oxford University Press (OUP)
Date: 28-12-2017
DOI: 10.1093/JAC/DKW539
Abstract: To investigate the genetic context associated with the emergence of vanA VRE in Australia. The whole genomes of 18 randomly selected vanA -positive Enterococcus faecium patient isolates, collected between 2011 and 2013 from hospitals in four Australian capitals, were sequenced and analysed. In silico typing and transposon lasmid assembly revealed that the sequenced isolates represented (in most cases) different hospital-adapted STs and were associated with a variety of different Tn 1546 variants and plasmid backbone structures. The recent emergence of vanA VRE in Australia was polyclonal and not associated with the dissemination of a single 'dominant' ST or vanA -encoding plasmid. Interestingly, the factors contributing to this epidemiological change are not known and future studies may need to consider investigation of potential community sources.
Publisher: Oxford University Press (OUP)
Date: 26-04-2016
DOI: 10.1093/JAC/DKW138
Publisher: Elsevier BV
Date: 10-2020
Publisher: American Chemical Society (ACS)
Date: 24-05-2016
Publisher: Oxford University Press (OUP)
Date: 25-06-2020
DOI: 10.1093/JAC/DKAA229
Abstract: Implementation of EUCAST susceptibility testing in an Australian hospital laboratory demonstrated higher rates of aminopenicillin and amoxicillin/clavulanate resistance in Haemophilus influenzae than previously recognized. This study aimed to better define the variability in the detection of β-lactam resistance based on EUCAST and CLSI disc diffusion (DD) methodology, by comparison with the recommended reference method, broth microdilution (BMD), and by concordance with genomic analysis. A total of 100 random H. influenzae isolates were assessed for icillin and amoxicillin/clavulanate susceptibility by EUCAST and CLSI DD and BMD. WGS was used to analyse the ftsI gene of a subset of isolates with β-lactam resistance, other than that due to isolated β-lactamase production. Of the 100 isolates, 32 were categorized as either β-lactamase negative, icillin resistant (BLNAR) (n = 18) or β-lactamase positive, amoxicillin/clavulanate resistant (BLPACR) (n = 14) by EUCAST DD. All 18 EUCAST BLNAR isolates were genotypically confirmed by WGS. Five of 18 BLNAR isolates were concordant by CLSI DD, 12 by EUCAST BMD and 4 by CLSI BMD. Nine of 14 EUCAST BLPACR isolates were confirmed by WGS the remaining 5 were 1 mm below the EUCAST DD breakpoint. Only one isolate was detected as BLPACR by CLSI DD. Group III mutations associated with high-level icillin resistance were identified in 10/32 isolates. The EUCAST DD susceptibility method is more reliable than either CLSI or BMD for the detection of genotypically defined BLNAR resistance. However, accurate categorization of amoxicillin/clavulanate resistance remains problematic. Continuous and reproducible surveillance of resistance is needed for this to be possible, robust susceptibility methods are required.
Publisher: Public Library of Science (PLoS)
Date: 06-01-2016
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 2019
Publisher: Elsevier BV
Date: 07-2020
Publisher: Public Library of Science (PLoS)
Date: 10-08-2012
Publisher: Elsevier BV
Date: 12-2014
DOI: 10.1016/J.JGAR.2014.09.003
Abstract: The objective of this review was to provide an up-to-date account of the interventions used to prevent the introduction of meticillin-resistant Staphylococcus aureus (MRSA) from the expanding community and livestock reservoirs into hospitals in the USA, Denmark, The Netherlands and Western Australia. A review of existing literature and local guidelines for the management of MRSA in hospitals was performed. In Denmark, The Netherlands and Western Australia, where the prevalence of MRSA is relatively low, targeted admission screening and isolation of predefined high-risk populations have been used for several decades to successfully control MRSA in the hospital. Furthermore, in Denmark and The Netherlands, all identified MRSA carriers undergo routine decolonisation, whereas only carriers of particularly transmissible or virulent MRSA clones are subjected to decolonisation in Western Australia. In the USA, which continues to be a high-prevalence MRSA country, policies vary by state and even by hospital, and whilst guidelines from professional organisations provide a framework for infection control practices, these guidelines lack the authority of a legislative mandate. In conclusion, the changing epidemiology of MRSA, exemplified by the recent emergence of MRSA in the community and in food animals, makes it increasingly difficult to accurately identify specific high-risk groups to screen for MRSA carriage. Understanding the changing epidemiology of MRSA in a local as well as global context is fundamental to prevent the introduction of MRSA into hospitals.
Publisher: Centers for Disease Control and Prevention (CDC)
Date: 10-2009
Publisher: Wiley
Date: 11-2017
DOI: 10.1111/IMJ.13609
Abstract: In this study, linked Western Australian health data were used to determine presence of an antibiotic-resistant infection (ABRI) for all people diagnosed with a primary invasive cancer in 2009. Of 10 858 cancer cases, 154 (1.42%) had an ABRI. Patients with an ABRI were older (71.5 vs 66 years), and more had died in the year following diagnosis (37.7 vs 20.2%, P < 0.001). The ABRI cohort had a higher proportion of colorectal, genitourinary and haematological cancers (19.5 vs 11.9% 14.3 vs 9.7% and 16.9 vs 5.8%, respectively). Hospital admissions with an ABRI were longer (22.3 vs 2.9 days, P < 0.001) and had a higher proportion of unplanned admissions (60.3 vs 15.2%), admissions through emergency department (36.8 vs 8.3%) and intensive care admissions (14.9 vs 1.7%, P < 0.001). Patients with solid tumours who developed an ABRI were more likely to have received chemotherapy (35.9 vs 27.8%, P = 0.04). In haematological cancer patients, a greater proportion of the admissions with an ABRI occurred after radiation therapy or chemotherapy (P = 0.01 and P = 0.005, respectively). This study is the first to report population-level data on ABRI in cancer patients. Patients with an ABRI had more hospital admissions and poorer outcomes.
Publisher: American Society for Microbiology
Date: 16-09-2021
DOI: 10.1128/MRA.00796-21
Abstract: Sequence type 1 (ST1) methicillin-resistant Staphylococcus aureus (MRSA) type IV[2B] has become one of the most common community-associated MRSA clones in Australia. We report the complete genome sequence of one of the earliest isolated Australian S. aureus ST1-MRSA-IV strains, WBG8287, isolated from an Indigenous Australian patient living in the remote Kimberley Region of Western Australia.
Publisher: Elsevier BV
Date: 09-2013
DOI: 10.1016/J.JGAR.2013.04.005
Abstract: The Australian Group on Antimicrobial Resistance (AGAR) performs regular multicentre period prevalence studies to monitor changes in antimicrobial resistance. In 2011, 29 laboratories in Australia participated in the national surveillance of Staphylococcus aureus resistance. The survey only included unique isolates from clinical specimens collected ≥48h after hospital admission. MRSA accounted for 30.3% of S. aureus isolates. MRSA resistance to ciprofloxacin, erythromycin, tetracycline, trimethoprim/sulfamethoxazole, gentamicin and clindamycin (constitutive resistance) varied considerably between regions. Resistance to non-β-lactam antimicrobials was uncommon in MSSA, with the exception of erythromycin. Regional variation in resistance was due to the differential distribution of MRSA clones between regions. The proportion of S. aureus genetically characterised as healthcare-associated MRSA (HA-MRSA) was significantly lower in this survey (18.2%) compared with the 2005 survey (24.2%) (P<0.0001). Although four HA-MRSA clones were characterised, 98.8% of HA-MRSA were classified as either ST22-MRSA-IV [2B] (EMRSA-15) or ST239-MRSA-III [3A] (Aus-2/3 EMRSA). Multiclonal community-associated MRSA (CA-MRSA) increased markedly from 6.5% in 2005 to 11.7% of all S. aureus in 2011 (P<0.0001). Although the proportion of MRSA resistant to non-β-lactam antimicrobials has decreased nationally, the proportion of S. aureus that are MRSA has remained stable. This is primarily due to non-multiresistant CA-MRSA becoming more common in Australian hospitals at the expense of the long-established multiresistant ST239-MRSA-III [3A] (Aus-2/3 EMRSA). Given hospital outbreaks of CA-MRSA are thought to be extremely rare, it is most likely that patients colonised at admission with CA-MRSA have become infected with the colonising strain during their hospital stay.
Publisher: Oxford University Press (OUP)
Date: 10-03-2020
DOI: 10.1093/JAC/DKAA065
Abstract: There is increasing knowledge of antimicrobial usage in children yet limited availability of nationally representative paediatric-specific data on antimicrobial resistance. Paediatric data from this national surveillance programme are presented to explore differences between childhood and adult bloodstream infections and antimicrobial resistance surveillance. Using information collected from a prospective coordinated antimicrobial resistance surveillance programme, children ≤18 years and adults & years with a positive blood culture for Staphylococcus aureus, Enterococcus spp. or Gram-negative spp. presenting to one of 34 Australian hospitals during 2013–16 were evaluated. Consistent methodologies for key sepsis pathogens were employed and a comparative analysis between children and adults was conducted. There are stark contrasts between children and adults in this national antimicrobial resistance (AMR) data set. Notable differences include lower rates of AMR, different clinical and molecular phenotypes and lower mortality amongst children. The burden of Gram-negative resistance is disproportionately experienced in children, with higher odds of death with an ESBL versus non-ESBL bacteraemia in comparison with adults. These data support that children are not just ‘little adults’ in the AMR era, and analyses by age group are important to detect differences in antibiotic susceptibility, clinical phenotype and genetic virulence factors. Antimicrobial surveillance incorporated into routine laboratory practice is vital to inform an array of wider applications including antimicrobial guidelines, stewardship and direction for prioritization of novel antimicrobial development.
Publisher: American Society for Microbiology
Date: 07-2018
DOI: 10.1128/JCM.00530-18
Publisher: Science Publications
Date: 2010
Publisher: Elsevier BV
Date: 06-2017
DOI: 10.1016/J.IJANTIMICAG.2017.01.030
Abstract: This study was conducted to investigate the epidemiology and antimicrobial susceptibility patterns of Gram-negative bacilli (GNB) isolated from intra-abdominal infections (IAIs) in the Asia-Pacific region (APR) from 2010-2013. A total of 17 350 isolates were collected from 54 centres in 13 countries in the APR. The three most commonly isolated GNB were Escherichia coli (46.1%), Klebsiella pneumoniae (19.3%) and Pseudomonas aeruginosa (9.8%). Overall, the rates of extended-spectrum β-lactamase (ESBL)-producing E. coli and K. pneumoniae were 38.2% and 24.3%, respectively, and they were highest in China (66.6% and 38.7%, respectively), Thailand (49.8% and 36.5%, respectively) and Vietnam (47.9% and 30.4%, respectively). During 2010-2013, the rates of ESBL-producing E. coli and K. pneumoniae isolates causing community-associated (CA) IAIs (collected 80%) causing IAIs, except for Acinetobacter calcoaceticus-baumannii (ACB) complex (30.9% for HA-IAI isolates). All of the antimicrobial agents tested exhibited <45% in vitro activity against ACB complex. Antimicrobial resistance is a persistent threat in the APR and continuous monitoring of evolutionary trends in the susceptibility patterns of GNB causing IAIs in this region is mandatory.
Publisher: Elsevier BV
Date: 12-1999
DOI: 10.1016/S0196-6553(99)70026-X
Abstract: This study was undertaken to determine the frequency of skin colonization, hub colonization, and central venous catheter colonization in transparent hydrocolloid versus standard polyurethane dressings. Adult patients requiring the insertion of a multilumen central venous catheter in an intensive care unit were randomized to receive either a standard polyurethane dressing or a transparent hydrocolloid dressing. Cultures were obtained from 125 skin insertion sites, 141 catheter hubs, 128 catheter tips, and blood s les from 132 patients. Extensive data on patient and catheter characteristics were collected. Skin and hub cultures revealed no significant difference in degree of colonization. However, the hydrocolloid group had a significantly higher level of catheter colonization than the polyurethane group (P =.048). Conversely, there was a significantly higher frequency of positive blood cultures in the polyurethane group (P =.03), although the majority were considered to be potential contaminants. There were only 6 cases in which the same species was simultaneously isolated from a positive blood culture and a colonized catheter, 5 from the hydrocolloid group and 1 from the polyurethane group. The results of this study suggest that an increased risk of catheter colonization is associated with the use of hydrocolloid dressings, despite previous research suggesting that they significantly reduce microbial growth compared with standard polyurethane. The clinical significance of increased numbers of positive blood cultures in the polyurethane group requires further examination, although distinguishing between contamination and true infection in intensive care settings continues to be methodologically challenging. Further studies are required to determine whether these findings are generalizable across different study settings and whether similar outcomes are obtained when different brands of hydrocolloid dressing are used.
Publisher: Frontiers Media SA
Date: 06-07-2018
Publisher: IOP Publishing
Date: 08-08-2013
Publisher: Oxford University Press (OUP)
Date: 22-12-2013
DOI: 10.1093/JAC/DKT499
Publisher: American Society for Microbiology
Date: 17-12-2020
DOI: 10.1128/JCM.02198-20
Abstract: Staphylococcus aureus ST45 is a major global MRSA lineage with huge strain ersity and a high clinical impact. It is one of the most prevalent carrier lineages but also frequently causes severe invasive disease, such as bacteremia. Little is known about its evolutionary history. In this study, we used whole-genome sequencing to analyze a large collection of 451 erse ST45 isolates from 6 continents and 26 countries. De novo -assembled genomes were used to understand genomic plasticity and to perform coalescent analyses.
Publisher: American Society for Microbiology
Date: 02-2013
DOI: 10.1128/JCM.02285-12
Abstract: Panton-Valentine leukocidin (PVL) is a virulence factor of Staphylococcus aureus , which is associated with skin and soft-tissue infections and necrotizing pneumonia. To develop a rapid phenotypic assay, recombinant PVL F component was used to generate monoclonal antibodies by phage display. These antibodies were spotted on protein microarrays and screened using different lukF-PV preparations and detection antibodies. This led to the identification of the optimal antibody combination that was then used to establish a lateral flow assay. This test was used to detect PVL in S. aureus cultures. The detection limit of the assay with purified native and recombinant antigens was determined to be around 1 ng/ml. Overnight cultures from various solid and liquid media proved suitable for PVL detection. Six hundred strains and clinical isolates from patients from America, Europe, Australia, Africa, and the Middle East were tested. Isolates were genotyped in parallel by DNA microarray hybridization for confirmation of PVL status and assignment to clonal complexes. The sensitivity, specificity, and positive and negative predictive values of the assay in this trial were 99.7, 98.3, 98.4, and 99.7%, respectively. A total of 302 clinical isolates and reference strains were PVL positive and were assigned to 21 different clonal complexes. In summary, the lateral flow test allows rapid and economical detection of PVL in a routine bacteriology laboratory. As the test utilizes cultures from standard media and does not require sophisticated equipment, it can be easily integrated into a laboratory's workflow and might contribute to timely therapy of PVL-associated infections.
Publisher: Cambridge University Press (CUP)
Date: 07-2007
DOI: 10.1086/518726
Abstract: To describe the control of an outbreak of infection and colonization with the New York/Japan methicillin-resistant Staphylococcus aureus (MRSA) clone in multiple healthcare facilities, and to demonstrate the importance of making an MRSA management policy involving molecular typing of MRSA into a statewide public health responsibility. A range of healthcare facilities, including 2 metropolitan teaching hospitals and a regional hospital, as well as several community hospitals and long-term care facilities in a nonmetropolitan healthcare region. A comprehensive, statewide MRSA epidemiological investigation and management policy. In May 2005, there were 3 isolates referred to the Western Australian Gram-Positive Bacteria Typing and Research Unit that were identified as the New York/Japan MRSA clone, a pandemic MRSA clone with the ability to spread and replace existing clones in a region. Subsequent investigation identified 28 additional cases of infection and/or colonization dating from 2002 onward, including 1 involving a colonized healthcare worker (HCW) who had previously been hospitalized overseas. Of the 31 isolates detected, 25 were linked epidemiologically and via molecular typing to the isolate recovered from the colonized HCW. Four isolates appeared to have been introduced separately from overseas. Although the isolate from the single remaining case patient was genetically indistinct from the isolates that spread within Western Australia, no specific epidemiological link could be established. The application of standard outbreak management strategies reduced further spread. The elimination of the New/York Japan MRSA clone in a healthcare region demonstrates the importance of incorporating MRSA management policy into statewide public health programs. The mainstays of such programs should include a comprehensive and effective outbreak identification and management policy (including pre-employment screening of HCWs, where applicable) and MRSA clone identification by multilocus sequence typing.
Publisher: Microbiology Society
Date: 08-2003
Abstract: The ability of phage-typing and SmaI chromosomal RFLPs to conclude appropriate strain relatedness between a collection of 12 well-characterized in vitro-selected vancomycin-intermediate Staphylococcus aureus (VISA) strains and their seven vancomycin-susceptible parent strains is reported. Generally, no SmaI RFLP alterations were observed in VISA strains when they were compared with their respective parent strains, and clonal relationships between isogenic strains were clearly evident. Unlike the SmaI RFLP results, parent strains and VISA derivatives generally did not share similar phage-typing profiles. Depending on the phage set investigated, some VISA strains even became untypable by this method. Loss of phage infectivity is probably due to cell wall (phage receptor) alterations that are expressed by the VISA strains investigated. Collectively, these findings indicate that inappropriate relationships between VISA and vancomycin-susceptible parents might be drawn if only phage-typing and antibiotic susceptibility are utilized to determine epidemiological relationships.
Publisher: American Society for Microbiology
Date: 10-2019
DOI: 10.1128/IAI.00528-19
Abstract: Burkholderia pseudomallei is the causative agent of melioidosis, a disease endemic to Southeast Asia and northern Australia. Mortality rates in these areas are high even with antimicrobial treatment, and there are few options for effective therapy. Therefore, there is a need to identify antibacterial targets for the development of novel treatments. Cyclophilins are a family of highly conserved enzymes important in multiple cellular processes.
Publisher: American Society for Microbiology
Date: 07-2013
DOI: 10.1128/AAC.00971-12
Abstract: The increasing trend of β-lactam resistance among Enterobacteriaceae is a worldwide threat. Enterobacteriaceae isolates causing intra-abdominal infections (IAI) from the Study for Monitoring Antimicrobial Resistance Trends (SMART) collected in 2008 and 2009 from the Asia-Pacific region were investigated. Detection of extended-spectrum β-lactamases (ESBLs), AmpC β-lactamases, and carbapenemases was performed by multiplex PCR. A total of 699 Enterobacteriaceae isolates with positive genotypic results, included Escherichia coli ( n = 443), Klebsiella pneumoniae ( n = 187), Enterobacter cloacae ( n = 45), Klebsiella oxytoca ( n = 9), Citrobacter freundii ( n = 5), Proteus mirabilis ( n = 3), Enterobacter aerogenes ( n = 2), Morganella morganii ( n = 2), and one each of Enterobacter asburiae , Proteus vulgaris , and Providencia rettgeri were analyzed. Nearly 20% of these β-lactamase-producing Enterobacteriaceae isolates were from community-associated IAI. CTX-M (588 isolates, including 428 [72.8%] with CTX-M-15) was the most common ESBL, followed by SHV ( n = 59) and TEM ( n = 4). CMY ( n = 110, including 102 [92.7%] with CMY-2) was the most common AmpC β-lactamase, followed by DHA ( n = 46) and ACT/MIR ( n = 40). NDM ( n = 65, including 62 [95.4%] with NDM-1) was the most common carbapenemase, followed by IMP ( n = 7) and OXA ( n = 7). Isolates from hospital-associated IAI had more complicated β-lactamase combinations than isolates from the community. Carbapenemases were all exclusively detected in Enterobacteriaceae isolates from India, except that IMP β-lactamases were also detected in Philippines and Australia. CTX-M β-lactamases were the predominant ESBLs produced by Enterobacteriaceae causing IAI in the Asia-Pacific region. Emergence of CTX-M-15-, CMY-2-, and NDM-1-producing Enterobacteriaceae isolates is of major concern and highlights the need for further surveillance in this area.
Publisher: Public Library of Science (PLoS)
Date: 17-11-2010
Publisher: American Society for Microbiology
Date: 03-2014
DOI: 10.1128/JCM.03286-13
Abstract: Enterococci are a major cause of health care-associated infections and account for approximately 10% of all bacteremias globally. The aim of this study was to determine the proportion of enterococcal bacteremia isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to icillin and the glycopeptides, and to characterize the molecular epidemiology of the Enterococcus faecalis and Enterococcus faecium isolates. From 1 January to 31 December 2011, 1,079 unique episodes of bacteremia were investigated, of which 95.8% were caused by either E. faecalis (61.0%) or E. faecium (34.8%). The majority of bacteremias were health care associated, and approximately one-third were polymicrobial. Ampicillin resistance was detected in 90.4% of E. faecium isolates but was not detected in E. faecalis isolates. Vancomycin nonsusceptibility was reported in 0.6% and 36.5% of E. faecalis and E. faecium isolates, respectively. Unlike Europe and the United States, where vancomycin resistance in E. faecium is predominately due to the acquisition of the vanA operon, 98.4% of E. faecium isolates harboring van genes carried the vanB operon, and 16.1% of the vanB E. faecium isolates had vancomycin MICs at or below the susceptible breakpoint of the CLSI. Although molecular typing identified 126 E. faecalis pulsed-field gel electrophoresis pulsotypes, % belonged to two pulsotypes that were isolated across Australia. E. faecium consisted of 73 pulsotypes from which 43 multilocus sequence types were identified. Almost 90% of the E. faecium isolates were identified as CC17 clones, of which approximately half were characterized as ST203, which was isolated Australia-wide. In conclusion, the Australian Enterococcal Sepsis Outcome Programme (AESOP) study has shown that although they are polyclonal, enterococcal bacteremias in Australia are frequently caused by icillin-resistant vanB E. faecium .
Publisher: Public Library of Science (PLoS)
Date: 06-04-2011
Publisher: Elsevier BV
Date: 06-2006
DOI: 10.1080/00313020600699227
Abstract: To describe clinical features and molecular epidemiology of non-multiresistant methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia. Patients with non-multiresistant MRSA isolated from blood at South Western Area Pathology Service from 1 January 1999 to 31 December 2001 were enrolled. Pulsed field gel electrophoresis, phage typing, and (selected instances) multilocus sequence and staphylococcal cassette chromosome typing was performed. PCR was used to detect Panton-Valentine leukocidin (PVL), toxic shock syndrome toxin-1 (TSST-1), and enterotoxin genes. Sixteen patients were detected: eight with UK EMRSA-15 (ST22-MRSA-IV), three with Oceania (South-West Pacific/Western Samoan phage pattern) (ST30-MRSA-IV), two with WA MRSA-5 (ST8-MRSA-IV), and one each with WA MRSA-1 (ST1-MRSA-IV), Queensland strain (ST93-MRSA-IV), and WA MRSA-15 (ST59-MRSA-IV). Prior hospital admissions occurred with six of the eight patients with UK EMRSA-15, none of the three with Oceania, and three of the five with other strains. Thirteen of 16 patients had underlying disease. Three of the three patients with Oceania strain bacteraemia were Polynesians 11 of 13 of the others were Caucasians. PVL genes were detected in four of 16 isolates (all Oceania and Queensland strains). entC was detected in two EMRSA-15 strains entA in one Oceania, two WA MRSA-5 and the WA MRSA-1 strain, with entA and entB in the WA MRSA-15 strain. tst was not detected. Multiple epidemic strains cause non-multiresistant MRSA bacteraemia. Most patients had risk factors. Oceania and Queensland strains possess the PVL gene.
Publisher: Oxford University Press (OUP)
Date: 08-2011
Abstract: There are concerns about reduced efficacy of vancomycin in patients with Staphylococcus aureus bacteremia (SAB), especially when the minimum inhibitory concentration (MIC) nears the upper limit of the susceptible range. We examined the relationship between antibiotic treatment, 30-day mortality, and microbiologic parameters in a large Australasian cohort of patients with SAB. We assessed 532 patients with SAB from 8 hospitals. All patients with methicillin-resistant S. aureus (MRSA) bacteremia were treated with vancomycin, and patients with methicillin-susceptible S. aureus (MSSA) bacteremia received either flucloxacillin or vancomycin. Increasing vancomycin MIC was associated with increased mortality in vancomycin-treated patients. However, even in patients with MSSA bacteremia treated with flucloxacillin, mortality was also higher if the vancomycin Etest MIC of their isolate was >1.5 μg/mL, compared with those with lower MIC isolates (26.8% vs 12.2% P < .001). After adjustment in a multivariate model, age, hospital-onset SAB and vancomycin MIC were independently associated with mortality, but methicillin resistance and antibiotic choice were not. We have confirmed an association between higher vancomycin MIC and increased mortality in patients with SAB, but surprisingly this relationship was not related to the antibiotic treatment received, suggesting that the use of vancomycin per se is not responsible for the poorer outcome.
Publisher: American Society for Microbiology
Date: 08-2019
DOI: 10.1128/JCM.00319-19
Abstract: Due to Australia’s management of antimicrobial use in poultry, particularly the discontinued use of avoparcin for nearly 20 years, it is hypothesized that vancomycin-resistant enterococci associated with human disease are not derived from poultry isolates.
Publisher: American Society for Microbiology
Date: 10-2010
DOI: 10.1128/JCM.00911-10
Abstract: Panton-Valentine leukocidin (PVL) has been linked to invasive community-acquired methicillin-resistant Staphylococcus aureus infections. However, the association between disease and PVL-positive methicillin-susceptible Staphylococcus aureus (MSSA) has not been widely reported. We aimed to examine the epidemiology of PVL in clinical MSSA isolates from patients presenting to Auckland City Hospital. Four hundred eleven MSSA clinical isolates and 93 nasal carriage isolates were collected and tested for the presence of the lukSF-PV genes using PCR. The results were examined in light of host and disease factors. Multilocus sequence typing (MLST) was performed on a random subset of isolates to ensure that there was no single PVL-positive MSSA clone responsible for disease in Auckland. The prevalence of the lukSF-PV genes in MSSA isolates associated with disease (124/335 37%) was not significantly different from the prevalence of the lukSF-PV genes in MSSA nasal carriage isolates (29/93 31% [ P = 0.33]). PVL-positive MSSA isolates in Auckland are genetically erse and come from a number of different clonal complexes. PVL-positive infections peaked at between 10 and 20 years of age, with a subsequent decline. Pacific ethnicity, age, diagnosis of skin and soft tissue infection (SSTI), community-onset infection, and the need for surgical intervention were found by multivariate analysis to be independently associated with PVL-positive MSSA infection. More than one-third of MSSA infections in our patient population are caused by PVL-positive strains. Those patients with PVL-positive MSSA infection were more likely to be of Pacific ethnicity, be younger in age, have community-onset infection, have SSTI, and need surgical intervention.
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JGAR.2018.08.016
Abstract: Enterococcus faecium is a robust opportunistic pathogen that is most commonly found as a commensal of the human and animal gut but can also survive in the environment. Since the introduction and use of antimicrobials, E. faecium has been found to rapidly acquire resistance genes that, when expressed, can effectively circumvent the effects of most antimicrobials. The rapid acquisition of multiple antimicrobial resistances has led to the adaptation of specific E. faecium clones in the hospital environment, collectively known as clonal complex 17 (CC17). CC17 E. faecium are responsible for a significant proportion of hospital-associated infections, which can cause severe morbidity and mortality. Here we review the history of E. faecium from commensal to a significant hospital-associated pathogen, its robust phenotypic characteristics, commonly used laboratory typing schemes, and antimicrobial resistances with a focus on vancomycin and its associated mechanism of resistance. Finally, we review the global epidemiology of vancomycin-resistant E. faecium and potential solutions to problems faced in public health.
Publisher: Elsevier BV
Date: 05-2008
DOI: 10.1016/J.IJANTIMICAG.2007.08.011
Abstract: A series of epidemics of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) have occurred in Australia, starting in Western Australia in the early 1990s, in the Northern Territory soon thereafter and in eastern states in the mid 1990s. The Western Australian epidemic has been due mainly to Panton-Valentine leukocidin (PVL)-negative clones, whilst PVL-positive clones have predominated in the east. More recently, the major epidemic clones have spread throughout the country, whilst multiple new minor clones have emerged, mainly in Western Australia. A total of 45 clones of CA-MRSA have been detected in Australia to date: 30 of these carry SCCmec IV, 6 carry SCCmec V and 9 carry novel SCCmec types. Overall, CA-MRSA clones have been associated predominantly with skin and soft-tissue infections. PVL-positive clones have been associated with furunculosis, necrotising pneumonia and osteomyelitis and have caused fatalities in otherwise healthy children and young adults. Initial treatment of these infections remains problematic, as it is frequently inappropriate. Of particular concern, healthcare-associated acquisition of CA-MRSA clones is now increasing, although major hospital outbreaks have not occurred yet.
Publisher: Elsevier BV
Date: 09-2021
Publisher: Elsevier BV
Date: 06-2022
DOI: 10.1016/J.JGAR.2022.03.012
Abstract: The role Staphylococcus aureus antimicrobial resistance genes and toxins play in disease severity, management and outcome in childhood is an emerging field requiring further exploration. A prospective multisite study of Australian and New Zealand children hospitalised with S. aureus bacteraemia (SAB) occurred over 24 months (2017-2018). Whole genome sequencing (WGS) data were paired with clinical information from the ISAIAH cohort. 353 SAB isolates were sequenced 85% methicillin-susceptible S. aureus ([MSSA], 301/353) and 15% methicillin-resistant S. aureus ([MRSA], 52/353). There were 92 sequence types (STs), most commonly ST5 (18%) and ST30 (8%), grouped into 23 clonal complexes (CCs), most frequently CC5 (21%) and CC30 (12%). MSSA comprised the majority of healthcare-associated SAB (87%, 109/125), with principal clones CC15 (48%, 11/21) and CC8 (33%, 7/21). Panton-Valentine leukocidin (PVL)-positive SAB occurred in 22% (76/353) predominantly MSSA (59%, 45/76), community-onset (92%, 70/76) infections. For community-onset SAB, the only microbiological independent predictor of poor outcomes was PVL positivity (aOR 2.6 [CI 1.0-6.2]). From this WGS paediatric SAB data, we demonstrate the previously under-recognized role MSSA has in harbouring genetic virulence and causing healthcare-associated infections. PVL positivity was the only molecular independent predictor of poor outcomes in children. These findings underscore the need for further research to define the potential implications PVL-producing strains may have on approaches to S. aureus clinical management.
Publisher: Oxford University Press (OUP)
Date: 03-08-2015
DOI: 10.1093/NAR/GKV755
Publisher: American Society for Microbiology
Date: 09-2014
DOI: 10.1128/JCM.01320-14
Abstract: An elevated vancomycin MIC is associated with poor outcomes in Staphylococcus aureus bacteremia (SAB) and is reported in patients with methicillin-susceptible S. aureus (MSSA) bacteremia in the absence of vancomycin treatment. Here, using DNA microarray and phenotype analysis, we investigated the genetic predictors and accessory gene regulator ( agr ) function and their relationship with elevated vancomycin MIC using blood culture isolates from a multicenter binational cohort of patients with SAB. Specific clonal complexes were associated with elevated (clonal complex 8 [CC8] [ P 0.001]) or low (CC22 [ P 0.001], CC88 [ P 0.001], and CC188 [ P = 0.002]) vancomycin MIC. agr dysfunction ( P = 0.014) or agr genotype II ( P = 0.043) were also associated with an elevated vancomycin MIC. Specific resistance and virulence genes were also linked to an elevated vancomycin MIC, including blaZ ( P = 0.002), sea ( P 0.001), clfA ( P 0.001), splA ( P = 0.001), and the arginine catabolic mobile element (ACME) locus ( P = 0.02). These data suggest that inherent organism characteristics may explain the link between elevated vancomycin MICs and poor outcomes in patients with SAB, regardless of the antibiotic treatment received. A consideration of clonal specificity should be included in future research when attempting to ascertain treatment effects or clinical outcomes.
Publisher: Oxford University Press (OUP)
Date: 26-08-2016
DOI: 10.1093/JAC/DKW317
Abstract: In Western Australia (WA), clonal complex 5, ST835, community-associated (CA) MRSA is isolated almost exclusively from aged care facilities. In WA four different staphylococcal cassette chromosome (SCC) mec (SCCmec) elements have been identified in this ST, indicating high genetic activity in the SCCmec region. To investigate the SCC region of ST835 CA-MRSA WA MRSA-40 and determine the distribution of an SCCsorbitol element found within the region. The SCC region contained a composite island, SCCmec Generation of SCCmec
Publisher: American Society for Microbiology
Date: 07-2013
DOI: 10.1128/JCM.00651-13
Abstract: Infective endocarditis (IE) is a life-threatening infection of the heart endothelium and valves. Staphylococcus aureus is a predominant cause of severe IE and is frequently associated with infections in health care settings and device-related infections. Multilocus sequence typing (MLST), spa typing, and virulence gene microarrays are frequently used to classify S. aureus clinical isolates. This study examined the utility of these typing tools to investigate S. aureus epidemiology associated with IE. Ninety-seven S. aureus isolates were collected from patients diagnosed with (i) IE, (ii) bloodstream infection related to medical devices, (iii) bloodstream infection not related to medical devices, and (iv) skin or soft-tissue infections. The MLST clonal complex (CC) for each isolate was determined and compared to the CCs of members of the S. aureus population by eBURST analysis. The spa type of all isolates was also determined. A null model was used to determine correlations of IE with CC and spa type. DNA microarray analysis was performed, and a permutational analysis of multivariate variance (PERMANOVA) and principal coordinates analysis were conducted to identify genotypic differences between IE and non-IE strains. CC12, CC20, and spa type t160 were significantly associated with IE S. aureus . A subset of virulence-associated genes and alleles, including genes encoding staphylococcal superantigen-like proteins, fibrinogen-binding protein, and a leukocidin subunit, also significantly correlated with IE isolates. MLST, spa typing, and microarray analysis are promising tools for monitoring S. aureus epidemiology associated with IE. Further research to determine a role for the S. aureus IE-associated virulence genes identified in this study is warranted.
Publisher: Wiley
Date: 25-07-2011
DOI: 10.1111/J.1440-1843.2011.01965.X
Abstract: Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains are primarily associated with skin and soft tissue infections however, they are increasingly causing more invasive infections including severe community-acquired pneumonia. The objective of this study was to describe the clinico-pathological characteristics of community-acquired MRSA pneumonia. A retrospective analysis of case records from January 2002 to August 2008 was performed on patients admitted with community-acquired MRSA pneumonia to two large teaching hospitals. Sixteen patients with community-acquired MRSA pneumonia were identified. Their age ranged from 11 months to 86 years (median age 30 years). Duration of symptoms before hospital presentation ranged from one to 21 days. Most patients had productive cough, fever and dyspnoea. The most common radiological presentation included multilobar consolidation (8/16), necrotizing consolidation (7/16) and empyema (5/16). Seven patients required intensive care support four required ionotropic support and five required mechanical ventilation for a mean duration of 53 h and 6.6 days, respectively. Six patients underwent surgery (VATS or open thoracotomy). There was a mean delay of approximately 69 h (range 18 h to 11 days) after presentation before appropriate MRSA antimicrobial treatment was initiated. Three patients died of complications from pneumonia, all within 72 h of presentation. Among survivors, the average length of hospital stay was 23.8 days (range 10-49 days). Majority of survivors were left with mild residual radiological changes. Community-acquired MRSA pneumonia is increasing and should be suspected in patients with severe community-acquired pneumonia. There was a delay in initiation of appropriate antimicrobial treatment that could have lead to increased morbidity.
Publisher: Oxford University Press (OUP)
Date: 04-10-2016
DOI: 10.1093/JAC/DKW398
Publisher: AMPCo
Date: 10-2009
DOI: 10.5694/J.1326-5377.2009.TB02841.X
Abstract: To document the types of, and mortality from, Staphylococcus aureus bacteraemia in Australia and New Zealand, and determine factors associated with mortality. Prospective observational study in 27 independent or hospital pathology laboratories in Australia (24) and New Zealand (3), employing a web-based database to prospectively record demographic features, selected risk factors, principal antibiotic treatment and mortality data on all patients with positive blood cultures for S. aureus from June 2007 to May 2008. 30-day all-cause mortality. 1994 episodes of S. aureus bacteraemia were identified, and complete 30-day follow-up data were available for 1865. Most episodes had their onset in the community (60.8% 95% CI, 58.7%-63.0%). Methicillin-resistant S. aureus (MRSA) caused 450 episodes (24.1% 95% CI, 22.2%-25.9%), and 123 of these (27.3%) had a susceptibility profile consistent with community-associated MRSA. All-cause mortality at 30 days was 20.6% (95% CI, 18.8%-22.5%). On univariate analysis, increased mortality was significantly associated with older age, European ethnicity, MRSA infection, infections not originating from a medical device, sepsis syndrome, pneumonia/empyema, and treatment with a glycopeptide or other non-beta-lactam antibiotic. On multivariable analysis, independent predictors of mortality were age, sepsis syndrome, pneumonia/empyema, device-associated infection with a secondary focus, left-sided endocarditis, and treatment with a glycopeptide such as vancomycin, but not MRSA infection. S. aureus bacteraemia is a common infection in both the community and hospitals in Australia and New Zealand, and is associated with appreciable mortality. Invasive MRSA infection may be more life-threatening, partly because of the inferior efficacy of the standard treatment, vancomycin. National web-based surveillance of S. aureus bacteraemia and its outcomes is not only important but also easily achievable.
Publisher: Oxford University Press (OUP)
Date: 05-04-2012
Abstract: It is uncertain whether particular clones causing invasive community-onset methicillin-resistant and methicillin-sensitive Staphylococcus aureus (cMRSA/cMSSA) infection differ in virulence. Invasive cMRSA and cMSSA cases were prospectively identified. Principal component analysis was used to derive an illness severity score (ISS) from clinical data, including 30-day mortality, requirement for intensive hospital support, the presence of bloodstream infection, and hospital length of stay. The mean ISS for each S. aureus clone (based on MLST) was compared with its DNA microarray-based genotype. Fifty-seven cMRSA and 50 cMSSA infections were analyzed. Ten clones caused 82 (77%) of these infections and had an ISS calculated. The enterotoxin gene cluster (egc) and the collagen adhesin (cna) gene were found in 4 of the 5 highest-ranked clones (ST47-MSSA, ST30-MRSA-IV[2B], ST45-MSSA, and ST22-MRSA-IV[2B]) compared with none and 1 of the lowest 5 ranked clones, respectively. cMSSA clones caused more severe infection than cMRSA clones. The lukF/lukS Panton-Valentine leukocidin (PVL) genes did not directly correlate with the ISS, being present in the second, fourth, and 10th most virulent clones. The clinical severity of invasive cMRSA and cMSSA infection is likely to be attributable to the isolates' entire genotype rather than a single putative virulence determinant such as PVL.
Publisher: American Society for Microbiology
Date: 11-2019
DOI: 10.1128/AAC.01560-19
Abstract: Horizontal transfer of plasmids encoding antimicrobial resistance and virulence determinants has been instrumental in Staphylococcus aureus evolution, including the emergence of community-associated methicillin-resistant S. aureus (CA-MRSA). In the early 1990s, the first CA-MRSA strain isolated in Western Australia (WA), WA-5, encoded cadmium, tetracycline, and penicillin resistance genes on plasmid pWBG753 (∼30 kb).
Publisher: Springer Science and Business Media LLC
Date: 12-2013
Publisher: Australian Government Department of Health
Date: 15-08-2019
Abstract: The Australian Group on Antimicrobial Resistance (AGAR) performs regular period-prevalence studies to monitor changes in antimicrobial resistance in selected enteric Gram-negative pathogens. The 2017 survey was the fifth year to focus on blood stream infections, and included Enterobacterales, Pseudomonas aeruginosa and Acinetobacter species. Seven thousand nine hundred and ten isolates, comprising Enterobacterales (7,100, 89.8%), P. aeruginosa (697, 8.8%) and Acinetobacter species (113, 1.4%), were tested using commercial automated methods. The results were analysed using Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints (January 2018). Of the key resistances, non-susceptibility to the third-generation cephalosporin, ceftriaxone, was found in 11.3%/11.3% of Escherichia coli (CLSI/EUCAST criteria), 8.8%/8.8% of Klebsiella pneumoniae, and 5.7%/5.7% of K. oxytoca. Non-susceptibility rates to ciprofloxacin were 12.1%/18.0% for E. coli, 4.4%/11.2% for K. pneumoniae, 1.3%/3.5% for K. oxytoca, 3.0%/8.5% for Enterobacter cloacae complex, and 5.1%/9.8% for P. aeruginosa. Resistance rates to piperacillin-tazobactam were 2.8%/5.9%, 3.7%/7.3%, 9.6%/11.0%, 22.5%/27.6%, and 6.4%/13.2% for the same five species respectively. Twenty-seven isolates from 25 patients were shown to harbour a carbapenemase gene: 12 bla[IMP] (11 patients), five bla[OXA-181] (four patients), three bla[OXA-23], two bla[NDM], two bla[KPC], two bla[VIM], and one bla[GES].
Publisher: Oxford University Press (OUP)
Date: 08-09-2016
DOI: 10.1093/CID/CIV808
Abstract: In vitro laboratory and animal studies demonstrate a synergistic role for the combination of vancomycin and antistaphylococcal β-lactams for methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. Prospective clinical data are lacking. In this open-label, multicenter, clinical trial, adults with MRSA bacteremia received vancomycin 1.5 g intravenously twice daily and were randomly assigned (1:1) to receive intravenous flucloxacillin 2 g every 6 hours for 7 days (combination group) or no additional therapy (standard therapy group). Participants were stratified by hospital and randomized in permuted blocks of variable size. Randomization codes were kept in sealed, sequentially numbered, opaque envelopes. The primary outcome was the duration of MRSA bacteremia in days. We randomly assigned 60 patients to receive vancomycin (n = 29), or vancomycin plus flucloxacillin (n = 31). The mean duration of bacteremia was 3.00 days in the standard therapy group and 1.94 days in the combination group. According to a negative binomial model, the mean time to resolution of bacteremia in the combination group was 65% (95% confidence interval, 41%-102% P = .06) that in the standard therapy group. There was no difference in the secondary end points of 28- and 90-day mortality, metastatic infection, nephrotoxicity, or hepatotoxicity. Combining an antistaphylococcal β-lactam with vancomycin may shorten the duration of MRSA bacteremia. Further trials with a larger s le size and objective clinically relevant end points are warranted. Australian New Zealand Clinical Trials Registry: ACTRN12610000940077 (www.anzctr.org.au).
Publisher: Springer Science and Business Media LLC
Date: 07-1999
DOI: 10.1038/EYE.1999.135
Publisher: Elsevier BV
Date: 06-2018
DOI: 10.1016/J.VETMIC.2018.04.004
Abstract: Methicillin-resistant coagulase-negative staphylococci (MRCoNS) have recently emerged as a significant cause of bovine mastitis worldwide. Here we describe the isolation of MRCoNS from cases of bovine mastitis from a single dairy farm in Australia. Fourteen CoNS isolates were identified as MRCoNS on the basis of having an oxacillin MIC of ≥0.5 μg/mL. The isolates were speciated as S. chromogenes (n = 1) S. fleurettii (n = 1), S. haemolyticus (n = 2), S. sciuri (n = 5), S. simulans (n = 1) S. succinus (n = 2) and S. xylosus (n = 2). Five of the isolates (S. fleuretti, S. haemolyticus S. sciuri and two S. succinus) were mecA-positive. We also detected a previously described S. sciuri mecA homolog in four oxacillin-resistant S. sciuri isolates. The remainder of the putative MRCoNS did not contain any mecA-related resistance determinants in their genomes. Comparative genomic analysis of three previously published S. sciuri isolates, from humans, a squirrel and a cereal crop (rice), and a representative isolate from our study demonstrated clustering and a high degree of genetic homogeneity (>95%), suggesting S. sciuri has low host specificity. In conclusion, CoNS, in particular S. sciuri, may act as a reservoir for SCCmec elements that can easily be spread between different host species by direct cross-infection.
Publisher: Oxford University Press (OUP)
Date: 08-2017
Abstract: There are few epidemiological data available to inform a national response to community-acquired methicillin-resistant Staphylococcus aureus (MRSA) in Papua New Guinea (PNG). We performed a cross-sectional survey to determine the pattern of MRSA nasal colonization and the ersity of circulating MRSA clones among adults and adolescents in Madang Province, PNG. S. aureus nasal colonization was confirmed in 44 (17.1%) of 257 participants. Four (9.1%) isolates were methicillin resistant. Resistance to other antimicrobial agents was uncommon. Detailed molecular typing of three MRSA isolates demonstrated multiple MRSA clones in this community, of which two carried the Panton-Valentin leukocidin-associated virulence genes. MRSA is likely to account for a clinically important proportion of staphylococcal disease in PNG. There are multiple MRSA clones in PNG. Ongoing surveillance of community and invasive isolates is a critical component of an effective response to the challenge of community-acquired MRSA in this and many other resource-limited contexts.
Publisher: American Society for Microbiology
Date: 30-08-2013
Abstract: Nosocomial outbreaks of vancomycin-resistant Enterococcus faecium (VREfm) are thought to occur by transmission of VREfm between patients, predicting that infection control interventions will limit cross-transmission. Despite implementation of such strategies, the incidence of VREfm infections continues to rise. We aimed to use genomics to better understand the epidemiology of E. faecium within a large hospital and investigate the reasons for failure of infection control strategies. Whole-genome sequencing was performed on 61 E. faecium (36 VREfm) isolates, predominately from blood cultures collected at a single hospital between 1998 and 2009, and on five vanB -positive anaerobic commensal bacteria isolated from human feces. Phylogenomic analysis and precise mapping of the vanB gene, which contains the Tn 1549 transposon, showed that at least 18 of the 36 VREfm isolates had acquired the transposon via independent insertion events, indicating de novo generation of VREfm rather than cross-transmission. Furthermore, Tn 1549 sequences found in 15 of the 36 VREfm isolates were the same as the Tn 1549 sequence from one of the gut anaerobes. National and international comparator E. faecium isolates were phylogenetically interspersed with isolates from our hospital, suggesting that our findings might be globally representative. These data demonstrate that VREfm generation within a patient is common, presumably occurring in the human bowel during antibiotic therapy, and help explain our inability to reduce VREfm infections. A recommendation from our findings is that infection control practices should include screening patients for specific hospital clones of vancomycin-susceptible E. faecium rather than just VREfm. IMPORTANCE Enterococcus faecium is an increasingly important human pathogen causing predominantly antibiotic-resistant infections in hospitalized patients. Large amounts of health care funding are spent trying to control antibiotic-resistant bacteria in hospitals globally, yet in many institutions around the world, vancomycin-resistant E. faecium (VREfm) infections continue to rise. The new findings from this study help explain the failures of our current approaches to controlling vanB VREfm in health care institutions. Given the importance of this bacterium as a cause of hospital-acquired infections and the difficulties faced by infection control units in trying to prevent colonization in their institutions, the novel findings from this study provide evidence that a new approach to controlling VREfm in hospitals is required. In particular, more attention should be given to understanding the epidemiology of hospital-adapted vancomycin-susceptible E. faecium , and patients at higher risk for de novo generation of VREfm need to be identified and optimally managed.
Publisher: Elsevier BV
Date: 2018
DOI: 10.1016/J.VETMIC.2017.11.018
Abstract: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an increasingly prevalent pathogen in veterinary medicine. This study examined the molecular epidemiology of clinical MRSP isolated from Australian animals. Clinical staphylococci submitted to all Australian veterinary diagnostic laboratories were collected during 2013 and identified using traditional phenotypic tests and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Phenotypic antimicrobial resistance was determined using broth microdilution and disk diffusion. MRSP isolates were characterized by whole genome sequencing which included identification of the mecA gene. Phylogenetic relationships were inferred by comparison of single nucleotide polymorphisms. Of the 669 S. pseudintermedius isolates collected from dogs, cats and cattle, 77 (11.5%) were MRSP. Nineteen multilocus sequence types (STs) were identified, with most isolates belonging to one of five STs (ST71, ST497, ST316, ST496 and ST45). Phylogenetic analysis revealed that Australian ST71 appears closely related to ST71 from overseas. ST497 and ST496 represented novel sequence types, not previously reported outside Australia. Most other STs were novel and only distantly related to each other. Geographical clustering of STs was observed. All isolates belonging to the five main STs were multi- to extensively- drug resistant while isolates from singleton STs generally had lower levels of antimicrobial resistance. The frequency of ciprofloxacin, trimethoprim-sulfamethoxazole, gentamicin, chlor henicol and tetracycline resistance varied significantly between STs (p<0.01). Australian MRSP isolates are phylogenetically erse, with a mix of previously unreported and well known international MRSP clones that demonstrate geographic clustering and exhibit both multidrug-resistant and extensively drug-resistant phenotypes.
Publisher: Informa UK Limited
Date: 28-02-2016
DOI: 10.1080/00480169.2016.1146171
Abstract: A 14-year-old neutered male Sealyham terrier was referred for assessment of a persistent pyoderma. It had experienced numerous episodes of dermatitis involving pododermatitis, pyoderma and otitis over the previous 6 years. Superficial, focally deep and mucocutaneous pyoderma were present, with yellow mucoid exudate on both nares and the lower lips crusted with haemopurulent exudate. Epidermal collarettes were present on the dorsal and lateral trunk. There were peri-anal crusts and mild erythema was present on the concave aspect of both pinnae. Culture and microbiological testing identified Staphylococcus pseudintermedius as the infecting organism. Kirby-Bauer disc susceptibility testing revealed the isolate was resistant to numerous antimicrobials including oxacillin. PCR testing of the isolate identified the presence of the mecA gene which confers resistance to β-lactam antimicrobials. Pulsed field gel electrophoresis typing suggested the isolate was not related to the methicillin-resistant S. pseudintermedius that had been reported to be associated with canine infections in Western Australia. Superficial, deep and mucus membrane pyoderma associated with a multi-drug resistant S. pseudintermedius. This is the first recorded case of canine pyoderma involving methicillin-resistant multidrug-resistant S. pseudintermedius in New Zealand. Treatment of such cases is difficult because the number of effective and available antimicrobials is limited. This finding should raise the awareness of the veterinary and medical professions to the presence of such organisms in New Zealand and stimulate a discussion about possible biosecurity barriers, treatment strategies and prevention of zoonotic and nosocomial infections.
Publisher: Elsevier BV
Date: 03-2007
DOI: 10.1111/J.1469-0691.2006.01635.X
Abstract: Within the last few years, methicillin-resistant Staphylococcus aureus (MRSA) strains encoding Panton-Valentine leukocidin (PVL) have emerged and spread worldwide. This epidemic can be attributed to a small number of distinct clones. The present study used a novel assay, based on multiplex linear DNA lification and subsequent microarray hybridisation, to simultaneously detect all relevant exotoxins, antimicrobial resistance determinants and the allelic variants of agr. The genes of the staphylococcal exotoxin-like (set) locus were also included for typing purposes. This assay, together with multilocus sequence typing (MLST) and spa typing, was applied to 56 clinical isolates and reference strains representing all major pandemic PVL-MRSA lineages, as well as to phylogenetically-related strains and putative ancestors. Array hybridisation results allowed the assignment of isolates to clonal groups, which were in accordance with MLST and spa typing data. Ten distinct clonal groups of PVL-MRSA (ST1, ST5, ST8, ST22, ST30, ST59/359, ST80/583, ST88, ST93 and ST152), including 12 MLST types, were identified and analysed with regard to resistance determinants and genes coding for exotoxins. The array hybridisation data confirmed that pandemic PVL-positive strains originate from very erse genetic backgrounds, and provided insights into the evolution of some lineages. The DNA microarray technique provides a valuable epidemiological tool for the detailed characterisation of clinical isolates and comparison of strains at a global level.
Publisher: Elsevier BV
Date: 2014
Publisher: Oxford University Press (OUP)
Date: 20-08-2019
DOI: 10.1093/JAC/DKZ361
Publisher: American Physical Society (APS)
Date: 15-04-2014
Publisher: Elsevier BV
Date: 03-2014
DOI: 10.1016/J.JGAR.2013.08.003
Abstract: The antibiotic susceptibility and molecular epidemiology of Panton-Valentine leukocidin (PVL)-positive meticillin-resistant Staphylococcus aureus (MRSA) isolates reported from 17 countries in the Americas, Europe and, Australia-Asia were analysed. Among a total of 3236 non-duplicate isolates, the lowest susceptibility was observed to erythromycin in all regions. Susceptibility to ciprofloxacin showed large variation (25%, 75% and 84% in the Americas, Europe and Australia-Asia, respectively). Two vancomycin-intermediate PVL-positive MRSA isolates were reported, one from Hong Kong and the other from The Netherlands. Resistance to trimethoprim/sulfamethoxazole and linezolid was <1%. Among 1798 MRSA isolates from 13 countries that were tested for the requested 10 non-β-lactam antibiotics, 49.4% were multisusceptible. However, multiresistant isolates (resistant to at least three classes of non-β-lactam antibiotics) were reported from all regions. Sequence type 30 (ST30) was reported worldwide, whereas ST80 and ST93 were exclusive to Europe and Australia, respectively. USA300 and related clones (ST8) are progressively replacing the ST80 clone in several European countries. Eight major clusters were discriminated by multilocus variable-number tandem repeat assay (MLVA), showing a certain geographic specificity. PVL-positive MRSA isolates frequently remain multisusceptible to non-β-lactam agents, but multiresistance is already prevalent in all regions. Surveillance of MRSA susceptibility patterns should be monitored to provide clinicians with the most current information regarding changes in resistance patterns.
Publisher: Elsevier BV
Date: 05-2015
Publisher: Oxford University Press (OUP)
Date: 28-10-2014
DOI: 10.1093/JAC/DKT436
Publisher: Elsevier BV
Date: 09-2016
DOI: 10.1016/J.JGAR.2016.04.004
Abstract: The evolution of meticillin-resistant Staphylococcus aureus (MRSA) from meticillin-susceptible S. aureus has been a result of the accumulation of genetic elements under selection pressure from antibiotics. The traditional classification of MRSA into healthcare-associated MRSA (HA-MRSA) and community-associated MRSA (CA-MRSA) is no longer relevant as there is significant overlap of identical clones between these groups, with an increasing recognition of human infection caused by livestock-associated MRSA (LA-MRSA). Genomic studies have enabled us to model the epidemiology of MRSA along these lines. In this review, we discuss the clinical relevance of genomic studies, particularly whole-genome sequencing, in the investigation of outbreaks. We also discuss the blurring of each of the three epidemiological groups (HA-MRSA, CA-MRSA and LA-MRSA), demonstrating the limited relevance of this classification.
Publisher: Mary Ann Liebert Inc
Date: 06-2004
Abstract: Antibiotic consumption during 1996 was measured in 15 large hospitals from 14 countries and 3000 consecutive Staphylococcus aureus s les were collected, allowing calculation of local resistance rates and typing of isolates. Antibiotic consumption data were converted to defined daily doses (DDD), and similar antibiotics were grouped if they belonged to the same therapeutic subgroup. Variations in hospital size were corrected by using DDD per 1000 bed-days. The total antibiotic consumption in the 15 hospitals varied between 296 DDD/1000 bed-days and 1108 DDD/1000 bed-days. Differences in the usage of therapeutical subgroups of antimicrobials varied significantly between hospitals. A positive correlation was found between S. aureus resistance to methicillin (MRSA) and consumption of beta-lactam combinations, between resistance to quinolones and consumption of beta-lactam combinations and carbapenems and resistance to aminoglycosides and consumption of beta-lactam combinations. The consumption of beta-lactamase-sensitive antibiotics was negatively correlated to resistance to methicillin, quinolones, and aminoglycosides. Usage of the different antimicrobial therapeutical subgroups was also correlated. Consumption of beta-lactamase-sensitive antibiotics (penicillin) was positively correlated to consumption of beta-lactamase-resistant penicillins and negatively correlated to consumption of carbapenems, quinolones, and glycopeptides, whereas consumption of cephalosporins was positively correlated to consumption of aminoglycosides, quinolones, and glycopeptides. In this study of hospitals with MRSA prevalence of between 0% and 63%, significant correlations were found between resistance and consumption of antimicrobials. These findings support the importance of antimicrobial consumption on resistance. An accompanying paper addresses the issue of antibiotic resistance and clonality of isolates.
Publisher: Elsevier BV
Date: 07-2014
Publisher: Australian Government Department of Health
Date: 16-09-2019
Abstract: From 1 January to 31 December 2017, 36 institutions around Australia participated in the Australian Enterococcal Sepsis Outcome Programme (AESOP). The aim of AESOP 2017 was to determine the proportion of enterococcal bacteraemia isolates in Australia that were antimicrobial resistant, and to characterise the molecular epidemiology of the E. faecium isolates. Of the 1,137 unique episodes of bacteraemia investigated, 95.2% were caused by either E. faecalis (52.9%) or E. faecium (42.3%). Ampicillin resistance was not detected in E. faecalis but in 89.6% of E. faecium. Vancomycin non-susceptibility was reported in 0.3% and 47.0% of E. faecalis and E. faecium respectively. Overall 50.9% of E. faecium harboured vanA or vanB genes. For the vanA/B positive E. faecium isolates, 49.6% harboured vanB genes and 49.2% vanA genes 1.2% harboured vanA and vanB genes. The percentage of E. faecium bacteraemia isolates resistant to vancomycin in Australia is significantly higher than that seen in most European countries. E. faecium consisted of 76 multilocus sequence types (STs) of which 77% of isolates were classified into nine major STs containing ten or more isolates. All major STs belong to clonal cluster (CC) 17, a major hospital-adapted polyclonal E. faecium cluster. Seven of the nine predominant STs (ST80, ST1421, ST17, ST296, ST555, ST203 and ST18) were found across most regions of Australia. The most predominant clone was ST17 which was identified in all regions except the Australian Capital Territory, the Northern Territory and Tasmania. Overall 60.7% of isolates belonging to the nine predominant STs harboured vanA or vanB genes. The AESOP 2017 has shown enterococcal bacteraemias in Australia are frequently caused by polyclonal icillin-resistant high-level gentamicin resistant vanA or vanB E. faecium which have limited treatment options.
Publisher: AMPCo
Date: 04-2006
DOI: 10.5694/J.1326-5377.2006.TB00287.X
Abstract: To describe antimicrobial resistance and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) isolated in community settings in Australia. Survey of S. aureus isolates collected prospectively Australia-wide between July 2004 and February 2005 results were compared with those of similar surveys conducted in 2000 and 2002. Up to 100 consecutive, unique clinical isolates of S. aureus from outpatient settings were collected at each of 22 teaching hospital and five private laboratories from cities in all Australian states and territories. They were characterised by antimicrobial susceptibilities (by agar dilution methods), coagulase gene typing, pulsed-field gel electrophoresis, multilocus sequence typing, SCCmec typing and polymerase chain reaction tests for Panton-Valentine leukocidin (PVL) gene. 2652 S. aureus isolates were collected, of which 395 (14.9%) were MRSA. The number of community-associated MRSA (CA-MRSA) isolates rose from 4.7% (118/2498) of S. aureus isolates in 2000 to 7.3% (194/2652) in 2004 (P = 0.001). Of the three major CA-MRSA strains, WA-1 constituted 45/257 (18%) of MRSA in 2000 and 64/395 (16%) in 2004 (P = 0.89), while the Queensland (QLD) strain increased from 13/257 (5%) to 58/395 (15%) (P = 0.0004), and the south-west Pacific (SWP) strain decreased from 33/257 (13%) to 26/395 (7%) (P = 0.01). PVL genes were detected in 90/195 (46%) of CA-MRSA strains, including 5/64 (8%) of WA-1, 56/58 (97%) of QLD, and 25/26 (96%) of SWP strains. Among health care-associated MRSA strains, all AUS-2 and AUS-3 isolates were multidrug-resistant, and UK EMRSA-15 isolates were resistant to ciprofloxacin and erythromycin (50%) or to ciprofloxacin alone (44%). Almost all (98%) of CA-MRSA strains were non-multiresistant. Community-onset MRSA continues to spread throughout Australia. The hypervirulence determinant PVL is often found in two of the most common CA-MRSA strains. The rapid changes in prevalence emphasise the importance of ongoing surveillance.
Publisher: Elsevier BV
Date: 06-2014
Publisher: American Society for Microbiology
Date: 03-2002
DOI: 10.1128/AAC.46.3.880-882.2002
Abstract: As part of the SENTRY antimicrobial surveillance program, we examined the prevalence rates, types, and antibiograms of oxacillin-resistant Staphylococcus aureus from hospitalized patients from 17 institutions in eight countries in Asia-Pacific and South Africa (APAC). From April 1998 to December 1999, a total of 1,711 isolates of S. aureus (814 from blood, 392 from the respiratory tract, 467 from skin and skin structures, and 38 from urine) were collected from hospitalized patients within the APAC region. Multidrug-resistant oxacillin-resistant S. aureus (MORSA) isolates, defined as strains with three or more resistances to drug classes other than β-lactams, were the most common type of oxacillin-resistant S. aureus (ORSA). They were the most frequently identified pathogen in wound infections and were common in bloodstream and lower respiratory tract infections. In all contributing institutions combined, more than 45% (range, 4 to 74%) of S. aureus isolates were oxacillin resistant, and in six institutions, this rate exceeded 60%. MORSA accounted for 91.2% of all oxacillin-resistant isolates. Distinct resistance patterns predominated at various sites within the APAC region, suggesting the local evolution of resistant clones. Non-multidrug-resistant strains were frequent in one part of Australia. No vancomycin-intermediate strains were detected, and no strains were resistant to linezolid or quinupristin-dalfopristin. MORSA strains are a very common cause of infection in hospitalized patients in the APAC region.
Publisher: American Society for Microbiology
Date: 16-09-2021
DOI: 10.1128/MRA.00797-21
Abstract: Initially reported in Western Australia in the 1980s, community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) has become a major cause of S. aureus infections globally. We report the complete genome sequences of three of the earliest CA-MRSA strains isolated from remote Australian Indigenous communities in the Kimberley region of Western Australia.
Publisher: CSIRO Publishing
Date: 2019
DOI: 10.1071/MA19020
Abstract: The Australian Group on Antimicrobial Resistance (AGAR) is a collaboration of clinicians and scientists working in diagnostic medical microbiology laboratories located across Australia. The group gathers information on the level of antimicrobial resistance (AMR) in bacteria causing important and life threatening infections and is a key component of Australia's response to the problem of increasing AMR. It defines where Australia stands with regard to antimicrobial resistance in human health.
Publisher: American Society for Microbiology
Date: 05-2015
Abstract: Infections caused by highly successful clones of hospital-associated methicillin-resistant Staphylococcus aureus (HA-MRSA) are a major public health burden. The globally dominant sequence type 239 (ST239) HA-MRSA clone has persisted in the health care setting for decades, but the basis of its success has not been identified. Taking a collection of 123 ST239 isolates spanning 32 years, we have used population-based functional genomics to investigate the evolution of this highly persistent and successful clone. Phylogenetic reconstruction and population modeling uncovered a previously unrecognized distinct clade of ST239 that was introduced into Australia from Asia and has perpetuated the epidemic in this region. Functional analysis demonstrated attenuated virulence and enhanced resistance to last-line antimicrobials, the result of two different phenomena, adaptive evolution within the original Australian ST239 clade and the introduction of a new clade displaying shifts in both phenotypes. The genetic ersity between the clades allowed us to employ genome-wide association testing and identify mutations in other essential regulatory systems, including walKR , that significantly associate with and may explain these key phenotypes. The phenotypic convergence of two independently evolving ST239 clades highlights the very strong selective pressures acting on HA-MRSA, showing that hospital environments have favored the accumulation of mutations in essential MRSA genes that increase resistance to antimicrobials, attenuate virulence, and promote persistence in the health care environment. Combinations of comparative genomics and careful phenotypic measurements of longitudinal collections of clinical isolates are giving us the knowledge to intelligently address the impact of current and future antibiotic usage policies and practices on hospital pathogens globally. IMPORTANCE Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for innumerable drug-resistant health care-associated infections globally. This study, the first to investigate the evolutionary response of hospital-associated MRSA (HA-MRSA) over many decades, demonstrates how MRSA can persist in a region through the reintroduction of a previously unrecognized distinct clade. This study also demonstrates the crucial adaptive responses of HA-MRSA to the highly selective environment of the health care system, the evolution of MRSA isolates to even higher levels of antibiotic resistance at the cost of attenuated virulence. However, in vivo persistence is maintained, resulting in a clone of HA-MRSA able to resist almost all antimicrobial agents and still cause invasive disease in the heavily compromised hosts found in modern health care settings.
Publisher: Springer Science and Business Media LLC
Date: 12-06-2010
DOI: 10.1007/S10096-010-0973-4
Abstract: Differences between the features of invasive community-onset methicillin-resistant Staphylococcus aureus (cMRSA) and methicillin-susceptible S. aureus (cMSSA) infections are incompletely understood. Fifty-seven patients with invasive cMRSA infection were prospectively identified at two teaching hospitals for each cMRSA case, two cases of invasive cMSSA infection acted as controls. The primary outcome was 30-day all-cause mortality. Patients with invasive cMRSA infection were more likely to be Aboriginal (25% vs. 14%, age-adjusted odds ratio [OR] 2.5, p = 0.037), reside in a long-term care facility and/or have been hospitalised in the previous year (51% vs. 34%, p = 0.04) and less likely to have endocarditis (2% vs. 12%, p = 0.02) or require admission to an intensive care unit or high-dependency area (7% vs. 21%, p = 0.02). All-cause mortality at 30 days was similar in the cMRSA and cMSSA groups (9% vs. 7%, p = 0.68). Panton-Valentine leukocidin (PVL) genes were detected in a similar proportion of cMRSA and cMSSA isolates (32% vs. 27%, p = 0.49) and the presence of PVL genes was associated with younger age (35 years vs. 55 years, p < 0.001), Aboriginal ethnicity (38% vs. 10%, p < 0.001), skin and soft-tissue infection (54% vs. 19%, p < 0.001), lower illness severity at presentation (SAPS II score 9 vs. 21, p = 0.001) and shorter hospitalisation (9 days vs. 24 days, p < 0.001). Patients with "PVL-positive" and "PVL-negative" S. aureus infection had similar 30-day all-cause mortality (4% vs. 9%, p = 0.28). Few clinical features differentiated patients with invasive cMRSA infection from those with infection caused by cMSSA. Invasive "PVL-positive" S. aureus infection was associated with less morbidity but similar mortality to "PVL-negative" infection.
Publisher: Elsevier BV
Date: 12-2003
DOI: 10.1016/S1201-9712(03)90104-4
Abstract: To investigate the incidence and epidemiology of non-multiresistant methicillin-resistant Staphylococcus aureus (nmMRSA) infection in south-east Queensland, Australia. A retrospective survey was done of hospital records of all patients who had non-multiresistant MRSA isolated at Ipswich Hospital (a 250-bed general hospital, 40 km south-west of Brisbane, Queensland, Australia) between March 2000 and June 2001. Laboratory typing of these isolates was done with antibiogram, pulsed-field gel electrophoresis, bacteriophage typing and coagulase gene typing. There were 44 infections caused by nmMRSA. Seventeen infections (39%) occurred in patients from the south-west Pacific Islands (predominantly Samoa, Tonga and New Zealand). Laboratory typing showed that the isolates in Pacific Islanders were Pacific Island strains, and 16/17 of these infections were community acquired. Twenty-three infections (52%) occurred in Caucasians. Eleven of the isolates from Caucasians (48%) were a new predominantly community-acquired strain that we have termed the 'R' pulsotype, nine (39%) were Pacific Island strains, and three (13%) were health care institution-associated strains. Four infections occurred in patients who were not Caucasians or Pacific Islanders. Overall, 34 of all 44 infections (77%) were community acquired. Non-multiresistant MRSA infection, relatively frequently observed in Pacific Islanders in south-east Queensland, is now a risk for Caucasians as well, and is usually community acquired. Clinicians should consider taking microbiological specimens for culture and antimicrobial susceptibility testing in patients with suspected staphylococcal infections who are not responding to empirical therapy with beta-lactam antibiotics.
Publisher: Elsevier BV
Date: 12-2019
DOI: 10.1016/J.IJANTIMICAG.2019.08.022
Abstract: Staphylococcus aureus is a serious human and animal pathogen. Multilocus sequence type 612 (ST612) is the dominant methicillin-resistant S. aureus (MRSA) clone in certain South African hospitals and is sporadically isolated from horses and horse-associated veterinarians in Australia. Colonisation and infection by ST612-MRSA is increasing in Western Australia. Whole-genome sequencing was performed for 51 isolates of ST612-MRSA from Western Australian patients and healthcare workers, South African hospital patients, Australian veterinarians and New South Wales horses. Core genome phylogenies suggested that Australian equine and veterinarian-associated ST612-MRSA were monophyletic. In idual Western Australian isolates grouped either with this equine-associated lineage or more erse lineages related to those in South African hospitals. Bioinformatic analyses of the complete ST612-MRSA reference genome SVH7513 confirmed that ST612-MRSA was closely related to ST8 USA500 MRSA. Common use of rif icin in South Africa and equine veterinarian practice may favour ST612-MRSA in these settings. Humans and horses colonised with ST612-MRSA are potential reservoirs for MRSA in Australia.
Publisher: Elsevier BV
Date: 2014
Publisher: Cambridge University Press (CUP)
Date: 05-2004
DOI: 10.1086/502410
Abstract: To demonstrate that nosocomial transmission of vancomycin-resistant enterococci (VRE) can be terminated and endemicity prevented despite widespread dissemination of an epidemic strain in a large tertiary-care referral hospital. Two months after the index case was detected in the intensive care unit, 68 patients became either infected or colonized with an epidemic strain of vanB vancomycin-resistant Enterococcus faecium despite standard infection control procedures. The following additional interventions were then introduced to control the outbreak: (1) formation of a VRE executive group (2) rapid laboratory identification (30 to 48 hours) using culture and polymerase chain reaction detection of van A and vanB resistance genes (3) mass screening of all hospitalized patients with isolation of carriers and cohorting of contacts (4) environmental screening and increased cleaning (5) electronic flagging of medical records of contacts and (6) antibiotic restrictions (third-generation cephalosporins and vancomycin). A total of 19,658 patient and 24,396 environmental swabs were processed between July and December 2001. One hundred sixty-nine patients in 23 wards were colonized with a single strain of vanB vancomycin-resistant E. faecium. Introducing additional control measures rapidly brought the outbreak under control. Hospital-wide screening found 39 previously unidentified colonized patients, with only 7 more nonsegregat-ed patients being detected in the next 2 months. The outbreak was terminated within 3 months at a cost of $2.7 million (Australian dollars). Despite widespread dissemination of VRE in a large acute care facility, eradication was achievable by a well-resourced, coordinated, multifaceted approach and was in accordance with good clinical governance.
Publisher: Elsevier BV
Date: 10-2017
DOI: 10.1016/J.JINF.2017.07.010
Abstract: Staphylococcus aureus skin and soft tissue infection (Sa-SSTI) places a significant burden on healthcare systems. New Zealand has a high incidence of Sa-SSTI, and here most morbidity is caused by a polyclonal methicillin-susceptible (MSSA) bacterial population. However, MSSA also colonise asymptomatically the cornified epithelia of approximately 20% of the population, and their ide between commensalism and pathogenicity is poorly understood. We aimed to see whether MSSA are genetically differentiated across colonisation and SSTI and given the close interactions between people and pets, whether strains isolated from pets differ from human strains. We compared the genomes of contemporaneous colonisation and clinical MSSA isolates obtained in New Zealand from humans and pets. Core and accessory genome comparisons revealed a homogeneous bacterial population across colonisation, disease, humans, and pets. The rate of MSSA colonisation in dogs was comparatively low (5.4%). In New Zealand, most Sa-SSTI morbidity is caused by a random s le of the colonising MSSA population, consistent with the opportunistic infection model rather than the paradigm distinguishing strains according to their pathogenicity. Thus, studies of the factors determining colonisation and immune-escape may be more beneficial than comparative virulence studies. Contact with house-hold pets may pose low zoonotic risk.
Publisher: Australian Government Department of Health
Date: 16-09-2019
Abstract: From 1 January to 31 December 2017, 36 institutions around Australia participated in the Australian Staphylococcus aureus Sepsis Outcome Programme (ASSOP). The aim of ASSOP 2017 was to determine the proportion of Staphylococcus aureus bacteraemia (SAB) isolates in Australia that are antimicrobial resistant, with particular emphasis on susceptibility to methicillin and to characterise the molecular epidemiology of the methicillin-resistant isolates. A total of 2,515 S. aureus bacteraemia episodes were reported, of which 77% were community-onset. Approximately one in five S. aureus (19.0%) were methicillin resistant. The 30-day all-cause mortality associated with methicillin-resistant SAB was 18.7% which was significantly higher than the 14.0% mortality associated with methicillin-susceptible SAB. With the exception of the β-lactams and erythromycin, antimicrobial resistance in methicillin-susceptible S. aureus was rare. However in addition to the β-lactams approximately 42% of methicillin-resistant S. aureus (MRSA) were resistant to erythromycin and ciprofloxacin and approximately 14% resistant to co-trimoxazole, tetracycline and gentamicin. When applying the EUCAST breakpoints teicoplanin resistance was detected in five S. aureus isolates. Resistance was not detected for vancomycin and linezolid. Resistance to non-beta-lactam antimicrobials was largely attributable to two healthcare-associated MRSA clones: ST22-IV [2B] (EMRSA-15) and ST239-III [3A] (Aus-2/3 EMRSA). ST22-IV [2B] (EMRSA-15) is the predominant healthcare-associated clone in Australia. Seventy-five percent of methicillin-resistant SAB were due to community-associated clones. Although polyclonal approximately 74% of community-associated clones were characterised as ST93-IV [2B] (Queensland CA-MRSA), ST5-IV [2B], ST45-VT [5C2& ] and ST1-IV [2B]. CA-MRSA, in particular the ST45-VT [5C2& ] clone has acquired multiple antimicrobial resistance determinants including ciprofloxacin, erythromycin, clindamycin, gentamicin and tetracycline. ST45-VT [5C2& ] accounted for 12.8% of CA-MRSA. As CA-MRSA is well established in the Australian community it is important antimicrobial resistance patterns in community- and healthcare-associated SAB is monitored as this information will guide therapeutic practices in treating S. aureus sepsis.
Publisher: Mary Ann Liebert Inc
Date: 03-2017
Abstract: This study aimed to determine the frequency and molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) from Australian animals and whether animal-derived MRSA was similar to that from Australian veterinarians. A total of 1,080 clinical coagulase positive Staphylococcus isolates from Australian animals were collected during 2013. Sixteen (4%) of 360 S. aureus isolates were MRSA. Most MRSA came from companion animals, while none came from livestock. MRSA isolates were characterized using whole genome sequencing. ST22-IV (EMRSA-15) was the most common clone in dogs and cats. Clonal complex (CC) 8 was most common in horses. Most ST22-IV isolates were resistant to ciprofloxacin. Animal-derived MRSA genomes were interrogated for the presence of host-specific genetic markers (staphylokinase gene [scn], chemotaxis-inhibiting proteins gene [chp], staphylococcal complement inhibitor gene [sak], enterotoxin A gene [sea], and Von Willebrand Factor binding protein gene [vwb]). A subset of MRSA genomes previously collected from Australian veterinarians was also interrogated. There was no clear pattern in the distribution of host-specific markers among animal and veterinarian isolates. Animal- and veterinarian-derived MRSA were intermingled in the phylogenetic tree. The absence of MRSA in Australian livestock is in stark contrast with its presence in livestock from other countries. Possible explanations include Australia's geographic isolation, the absence of live animal importation into Australia, and most notably, the restrictions placed on the use of antimicrobials of critical importance in Australian livestock.
Publisher: Springer Science and Business Media LLC
Date: 27-02-2018
Publisher: Springer Science and Business Media LLC
Date: 09-01-2015
Publisher: American Society for Microbiology
Date: 06-2005
DOI: 10.1128/JCM.43.6.2969-2972.2005
Abstract: Seventy-one percent of 76 methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from two medical centers in El Paso, Texas, represent three similar pulsed-field gel electrophoresis types. Overall, six pulsed-field types were identified represented by multilocus sequence/staphylococcal chromosomal cassette DNA mec (SCC mec ) types: ST5-MRSA-II ST36-MRSA-II ST8 (untypeable SCC mec ) and a newly described clonal cluster 8 strain, ST507-MRSA-IV. This study demonstrates the presence of multiple-antibiotic-resistant epidemic MRSA clones in El Paso.
Publisher: Oxford University Press (OUP)
Date: 1996
DOI: 10.1093/JAC/38.3.551
Abstract: SARS-CoV-2 accesses host cells via angiotensin-converting enzyme-2, which is also affected by commonly used angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs), raising concerns that ACEI or ARB exposure may portend differential COVID-19 outcomes. In parallel cohort studies of outpatient and inpatient COVID-19-diagnosed adults with hypertension, we assessed associations between antihypertensive exposure (ACEI/ARB vs. non-ACEI/ARB antihypertensives, as well as between ACEI- vs. ARB) at the time of COVID-19 diagnosis, using electronic health record data from PCORnet health systems. The primary outcomes were all-cause hospitalization or death (outpatient cohort) or all-cause death (inpatient), analyzed via Cox regression weighted by inverse probability of treatment weights. From February 2020 through December 9, 2020, 11,246 patients (3477 person-years) and 2200 patients (777 person-years) were included from 17 health systems in outpatient and inpatient cohorts, respectively. There were 1015 all-cause hospitalization or deaths in the outpatient cohort (incidence, 29.2 events per 100 person-years), with no significant difference by ACEI/ARB use (adjusted HR 1.01 95% CI 0.88, 1.15). In the inpatient cohort, there were 218 all-cause deaths (incidence, 28.1 per 100 person-years) and ACEI/ARB exposure was associated with reduced death (adjusted HR, 0.76 95% CI, 0.57, 0.99). ACEI, versus ARB exposure, was associated with higher risk of hospitalization in the outpatient cohort, but no difference in all-cause death in either cohort. There was no evidence of effect modification across pre-specified baseline characteristics. Our results suggest ACEI and ARB exposure have no detrimental effect on hospitalizations and may reduce death among hypertensive patients diagnosed with COVID-19.
Start Date: 2017
End Date: 07-2018
Amount: $510,000.00
Funder: Australian Research Council
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