ORCID Profile
0000-0002-4053-1610
Current Organisations
University of Adelaide
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SA Pathology
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Publisher: Springer Science and Business Media LLC
Date: 09-07-2020
DOI: 10.1186/S12866-020-01891-8
Abstract: Diabetic foot ulcer (DFU) is a serious complication of diabetes mellitus. Antibiotic-resistant Staphylococcus aureus is frequently isolated from DFU infections. Bacteriophages (phages) represent an alternative or adjunct treatment to antibiotic therapy. Here we describe the efficacy of AB-SA01, a cocktail of three S. aureus Myoviridae phages, made to current good manufacturing practice (cGMP) standards, and which has undergone two phase I clinical trials, in treatment of multidrug-resistant (MDR) S. aureus infections. Wounds of saline-treated mice showed no healing, but expanded and became inflamed, ulcerated, and suppurating. In contrast, AB-SA01 treatment decreased the bacterial load with efficacy similar or superior to vancomycin treatment. At the end of the treatment period, there was a significant decrease (p 0.001) in bacterial load and wound size in infected phage- and vancomycin-treated groups compared with infected saline-treated mice. In phage-treated mice, wound healing was seen similar to vancomycin treatment. No mortality was recorded associated with infections, and post-mortem examinations did not show any evident pathological lesions other than the skin wounds. No adverse effects related to the application of phages were observed. Topical application of phage cocktail AB-SA01 is effective, as shown by bacterial load reduction and wound closure, in the treatment of diabetic wound infections caused by MDR S. aureus . Our results suggest that topical phage cocktail treatment may be effective in treating antibiotic-resistant S. aureus DFU infections.
Publisher: Massachusetts Medical Society
Date: 31-10-2019
DOI: 10.1056/NEJMC1908355
Publisher: Wiley
Date: 03-09-2023
DOI: 10.5694/MJA2.52077
Publisher: Springer Science and Business Media LLC
Date: 30-01-2021
Publisher: Wiley
Date: 03-2016
DOI: 10.1002/JPPR.1193
Publisher: Wiley
Date: 15-11-2022
DOI: 10.1111/TID.13988
Abstract: Limited consensus exists on the optimal use of antifungal agents to prevent invasive fungal infection in the early post allogeneic hematopoietic stem cell transplant (alloHCT) period, particularly when patients cannot tolerate oral medication administration. We undertook a retrospective observational cohort study to assess the tolerability, efficacy, and cost of a new antifungal prophylaxis pathway at a major tertiary alloHCT centre. Patients aged ≥16 years who underwent alloHCT between February 2018 and October 2019 (cohort 1) or between April 2020 and November 2021 (cohort 2) were included. In both cohorts, first line prophylactic therapy was oral posaconazole. The second line drugs where oral therapy was unable to be administered were intravenous voriconazole (cohort 1) versus intravenous posaconazole (cohort 2). There were 142 patients enrolled in the study, 71 in each cohort. The proportion of patients remaining on first‐line prophylaxis or progressing to second‐, third‐, and fourth‐line options was 22.5%, 39.4%, 29.6%, and 8.5% in cohort 1 and 39.4%, 59.2%, 1.4%, and 0% in cohort 2, respectively. The frequency of neuropsychiatric adverse events was significantly higher in cohort 1 compared to cohort 2 (49.3% vs. 19.8%, p = .0004). Occurrence of proven and probable fungal infections was not significantly different between cohorts. Antifungal drug expenditure was $359 935 (AUD) more in cohort 1 ($830 486 AUD) compared to cohort 2 ($477 149 AUD). The antifungal prophylaxis pathway used in cohort 2 resulted in reduced antifungal‐associated adverse effects, less patients requiring progression to 3rd and 4th line prophylaxis and reduced antifungal drug costs. image
Publisher: American Society for Microbiology
Date: 09-2015
DOI: 10.1128/AAC.00389-15
Abstract: While guidelines recommend empirical cefepime therapy in febrile neutropenia, the mortality benefit of cefepime has been controversial. In light of this, recent reports on pharmacokinetic changes for several antibiotics in febrile neutropenia and the consequent suboptimal exposure call for a pharmacokinetic harmacodynamic evaluation of current dosing. This study aimed to assess pharmacokinetic harmacodynamic target attainment from a 2-g intravenous (i.v.) every 8 h (q8h) cefepime regimen in febrile neutropenic patients with hematological malignancies. Cefepime plasma concentrations were measured in the 3rd, 6th, and 9th dosing intervals at 60% of the interval and/or trough point. The selected pharmacokinetic harmacodynamic targets were the proportion of the dosing interval (60% and 100%) for which the free drug concentration remains above the MIC ( f T MIC ). Target attainment was assessed in reference to the MIC of isolated organisms if available or empirical breakpoints if not. The percentage of f T MIC was also estimated by log-linear regression analysis. All patients achieved % f T MIC in the 3rd and 6th dosing intervals. A 100% f T MIC was not attained in 6/12, 4/10, and 4/9 patients in the 3rd, 6th, and 9th dose intervals, respectively, or in 14/31 (45%) of the dosing intervals investigated. On the other hand, 29/31 (94%) of trough concentrations were at or above 4 mg/liter. In conclusion, for patients with normal renal function, a high-dose 2-g i.v. q8h cefepime regimen appears to provide appropriate exposure if the MIC of the organism is ≤4 mg/liter but may fail to cover less susceptible organisms.
Publisher: Wiley
Date: 11-2020
DOI: 10.1111/ANS.16214
Publisher: Springer Science and Business Media LLC
Date: 14-03-2022
DOI: 10.1007/S10029-022-02583-0
Abstract: The purpose of this study was to investigate the link between bacterial biofilms and negative outcomes of hernia repair surgery. As biofilms are known to play a role in mesh-related infections, we investigated the presence of biofilms on hernia meshes, which had to be explanted due to mesh failure without showing signs of bacterial infection. In this retrospective observational study, 20 paraffin-embedded tissue sections from explanted groin hernia meshes were analysed. Meshes have been removed due to chronic pain, hernia recurrence or mesh shrinkage. The presence and bacterial composition of biofilms were determined. First, specimens were stained with fluorescence in situ hybridisation (FISH) probes, specific for Staphylococcus aureus and coagulase-negative staphylococci, and visualised by confocal laser scanning microscopy. Second, DNA was extracted from tissue and identified by S. aureus and S. epidermidis specific PCR. Confocal microscopy showed evidence of bacterial biofilms on meshes in 15/20 (75.0%) s les, of which 3 were positive for S. aureus , 3 for coagulase-negative staphylococci and 9 for both species. PCR analysis identified biofilms in 17/20 (85.0%) s les, of which 4 were positive for S. aureus , 4 for S. epidermidis and 9 for both species. Combined results from FISH/microscopy and PCR identified staphylococci biofilms in 19/20 (95.0%) mesh s les. Only 1 (5.0%) mesh s le was negative for bacterial biofilm by both techniques. Results suggest that staphylococci biofilms may be associated with hernia repair failure. A silent, undetected biofilm infection could contribute to mesh complications, chronic pain and exacerbation of disease.
Publisher: Wiley
Date: 31-03-2022
DOI: 10.1111/JGH.15832
Abstract: Rates of antimicrobial‐resistant Helicobacter pylori infection are rising globally however, geospatial location and its interaction with risk factors for infection have not been closely examined. Gastric biopsy specimens were collected to detect H. pylori infection at multiple centers in Adelaide, South Australia, between 1998 and 2017. The geospatial distribution of antibiotic‐resistant H. pylori in the Greater Adelaide region was plotted using choropleth maps. Moran's I was used to assess geospatial correlation, and multivariate linear regression (MLR) was used to examine associations between migration status, socioeconomic status, age, gender, and rates of H. pylori positivity and antibiotic resistance. Geographically weighted regression (GWR) was used to determine the extent to which the associations varied according to geospatial location. Of 20 108 biopsies across 136 postcodes within the Greater Adelaide region, 1901 (9.45%) were H. pylori positive. Of these, 797 (41.9%) displayed clarithromycin, tetracycline, metronidazole, or amoxicillin resistance. In MLR, migration status was associated with the rate of H. pylori positivity ( β = 3.85% per 10% increase in a postcode's migrant population P 0.001). H. pylori positivity and resistance to any antibiotic were geospatially clustered (Moran's I = 0.571 and 0.280, respectively P 0.001 for both). In GWR, there was significant geospatial variation in the strength of the migrant association for both H. pylori positivity and antibiotic resistance. Our study demonstrates the heterogeneous geospatial distribution of H. pylori positivity and antibiotic resistance, as well as its interaction with migrant status. Geographic location and migrant status are important factors to consider for H. pylori eradication therapy.
Publisher: MDPI AG
Date: 18-05-2020
DOI: 10.3390/V12050559
Abstract: The efficacy of phages in multispecies infections has been poorly examined. The in vitro lytic efficacies of phage cocktails AB-SA01, AB-PA01, which target Staphylococcus aureus and Pseudomonas aeruginosa, respectively, and their combination against their hosts were evaluated in S. aureus and P. aeruginosa mixed-species planktonic and biofilm cultures. Green fluorescent protein (GFP)-labelled P. aeruginosa PAO1 and mCherry-labelled S. aureus KUB7 laboratory strains and clinical isolates were used as target bacteria. During real-time monitoring using fluorescence spectrophotometry, the density of mCherry S. aureus KUB7 and GFP P. aeruginosa PAO1 significantly decreased when treated by their respective phage cocktail, a mixture of phage cocktails, and gentamicin. The decrease in bacterial density measured by relative fluorescence strongly associated with the decline in bacterial cell counts. This microplate-based mixed-species culture treatment monitoring through spectrophotometry combine reproducibility, rapidity, and ease of management. It is amenable to high-throughput screening for phage cocktail efficacy evaluation. Each phage cocktail, the combination of the two phage cocktails, and tetracycline produced significant biofilm biomass reduction in mixed-species biofilms. This study result shows that these phage cocktails lyse their hosts in the presence of non-susceptible bacteria. These data support the use of phage cocktails therapy in infections with multiple bacterial species.
Publisher: Wiley
Date: 19-08-2022
DOI: 10.1111/IMJ.15640
Abstract: Helicobacter pylori infection is responsible for considerable morbidity and mortality worldwide, and eradication rates are falling in many countries, primarily due to clarithromycin and metronidazole resistance. There is a paucity of contemporary Australian data, which we sought to address by evaluating local rates of resistance of H. pylori to amoxicillin, clarithromycin, metronidazole and tetracycline over the past 20 years. All gastric biopsy specimens collected at endoscopy to detect H. pylori infection at a single centre underwent routine culture and antibiotic susceptibility testing between 1998 and 2017. Specimens from 12 842 patients were cultured for H. pylori, of which 1473 positive cultures were tested for antibiotic susceptibility. Antibiotic resistance to clarithromycin increased by 3.7% per year (incidence rate ratio [IRR] 1.037 P = 0.014) over 20 years, with a corresponding 5.0% annual increase in minimum inhibitory concentration (MIC) (odds ratio 1.050 P 0.001). Since 2010, average clarithromycin resistance has exceeded 20%, with % of isolates resistant in the past 2 years of data capture. In contrast, rates of resistance to metronidazole (35.3%), amoxicillin (0.14%) and tetracycline (0.34%) and their MIC have remained stable. Review of a representative s le ( n = 120 8%) of these patients revealed that only 5% had documented prior H. pylori eradication therapy. Over the past 20 years there has been a substantial rise in clarithromycin resistance, with stable metronidazole resistance and low rates of resistance to amoxicillin and tetracycline. Current first‐line H. pylori eradication therapy may fail to achieve adequate eradication rates, and optimal first‐line therapy in Australia should be revisited.
Publisher: Wiley
Date: 05-2022
DOI: 10.1111/IMJ.15784
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-2010
Publisher: Elsevier BV
Date: 06-1998
Abstract: Certain mutant strains of herpes simplex virus type 1 (HSV-1) are unable to infect cells in which entry is dependent on HVEM, the previously described herpesvirus entry mediator designated here as herpesvirus entry protein A (HveA). These mutant viruses can infect other cells where entry is apparently dependent on other co-receptors. The mutant virus HSV-1(KOS)Rid1 was used to screen a human cDNA expression library for ability of transfected plasmids to convert resistant Chinese hamster ovary cells to susceptibility to virus entry. A plasmid expressing the previously described poliovirus receptor-related protein 2 (Prr2) was isolated on the basis of this activity. This protein, designated here as HveB, was shown to mediate the entry of three mutant HSV-1 strains that cannot use HVEM as co-receptor, but not wild-type HSV-1 strains. HveB also mediated the entry of HSV-2 and pseudorabies virus but not bovine herpesvirus type 1. HveB was expressed in some human neuronal cell lines, fibroblastic cells, keratinocytes, and primary activated T lymphocytes. Antibodies specific for HveB blocked infection of HveB-expressing CHO cells and a human fibroblastic cell strain HEL299. Differences in ability of HSV-1 and HSV-2 strains to use HveB for entry should influence the types of cells that can be infected and thereby account in part for serotype and strain differences in tissue tropism and pathogenicity.
Publisher: Springer Science and Business Media LLC
Date: 08-12-2012
DOI: 10.1007/S15010-012-0374-Y
Abstract: Clinical patterns of Klebsiella pneumoniae bacteraemia vary geographically. An invasive syndrome involving abscess formation has emerged in recent years. Putative virulence factors associated with this syndrome include colony hypermucoviscosity, and magA and rmpA genes. We studied epidemiologic and microbiologic characteristics of K. pneumoniae bacteraemia at two South Australian hospitals and identified cases of K. pneumoniae invasive syndrome. We determined the frequency of the hypermucoviscosity, magA and rmpA genes among bacteraemic and selected non-bacteraemic isolates. Thirty-one patients with K. pneumoniae bacteraemia treated between June 2010 and July 2011 were included. Existing records were examined for relevant clinical and microbiological data. Urinary and wound isolates were also examined. Hypermucoviscosity was identified by a positive string test, whilst polymerase chain reaction detected magA and rmpA positive isolates. Of 31 blood culture isolates, 22 were associated with community-acquired infection. Biliary infection was the commonest source, occurring in ten patients. Three patients had K. pneumoniae invasive syndrome, all of Asian extraction (p = 0.0044). Four blood isolates demonstrated one or more of hypermucoviscosity, magA or rmpA three were from patients with liver abscesses. Liver abscess isolates were all K1 serotype and had similar PFGE profiles. This study augments understanding of local epidemiology and microbiology of K. pneumoniae bacteraemia. It confirms local emergence of K. pneumoniae invasive syndrome and implicates the role of magA and rmpA genes in its pathogenesis.
Publisher: American Society for Microbiology
Date: 08-1997
DOI: 10.1128/JVI.71.8.6083-6093.1997
Abstract: Glycoprotein D (gD) is a structural component of the herpes simplex virus (HSV) envelope which is essential for virus entry into host cells. Chinese hamster ovary (CHO-K1) cells are one of the few cell types which are nonpermissive for the entry of many HSV strains. However, when these cells are transformed with the gene for the herpesvirus entry mediator (HVEM), the resulting cells, CHO-HVEM12, are permissive for many HSV strains, such as HSV-1(KOS). By virtue of its four cysteine-rich pseudorepeats, HVEM is a member of the tumor necrosis factor receptor superfamily of proteins. Recombinant forms of gD and HVEM, gD-1(306t) and HVEM(200t), respectively, were used to demonstrate a specific physical interaction between these two proteins. This interaction was dependent on native gD conformation but independent of its N-linked oligosaccharides, as expected from previous structure-function studies. Recombinant forms of gD derived from HSV-1(KOS)rid1 and HSV-1(ANG) did not bind to HVEM(200t), explaining the inability of these viruses to infect CHO-HVEM12 cells. A variant gD protein, gD-1(delta290-299t), showed enhanced binding to HVEM(200t) relative to the binding of gD-1(306t). Competition studies showed that gD-1(delta290-299t) and gD-1(306t) bound to the same region of HVEM(200t), suggesting that the differences in binding to HVEM are due to differences in affinity. These differences were also reflected in the ability of gD-1(delta290-299t) but not gD-1(306t) to block HSV type 1 infection of CHO-HVEM12 cells. By gel filtration chromatography, the complex between gD-1(delta290-299t) and HVEM(200t) had a molecular mass of 113 kDa and a molar ratio of 1:2. We conclude that HVEM interacts directly with gD, suggesting that HVEM is a receptor for virion gD and that the interaction between these proteins is a step in HSV entry into HVEM-expressing cells.
Publisher: Oxford University Press (OUP)
Date: 07-05-2015
DOI: 10.1093/JAC/DKV123
Abstract: The objectives of this study were to describe piperacillin exposure in febrile neutropenia patients and determine whether therapeutic drug monitoring (TDM) can be used to increase the achievement of pharmacokinetic (PK) harmacodynamic (PD) targets. In a prospective randomized controlled study (Australian New Zealand Registry, ACTRN12615000086561), patients were subjected to TDM for 3 consecutive days. Dose was adjusted in the intervention group to achieve a free drug concentration above the MIC for 100% of the dose interval (100% fT& MIC), which was also the primary outcome measure. The secondary PK/PD target was 50% fT& MIC. Duration of fever and days to recovery from neutropenia were recorded. Thirty-two patients were enrolled. Initially, patients received 4.5 g of piperacillin/tazobactam every 8 h or every 6 h along with gentamicin co-therapy in 30/32 (94%) patients. At the first TDM, 7/32 (22%) patients achieved 100% fT& MIC and 12/32 (38%) patients achieved 50% fT& MIC. Following dose adjustment, 11/16 (69%) of intervention patients versus 3/16 (19%) of control patients (P = 0.012) attained 100% fT& MIC, and 15/16 (94%) of intervention patients versus 5/16 (31%) of control patients (P = 0.001) achieved 50% fT& MIC. After the third TDM, the proportion of patients attaining 100% fT& MIC improved from a baseline 3/16 (19%) to 11/15 (73%) in the intervention group, while it declined from 4/16 (25%) to 1/15 (7%) in the control group. No difference was noted in the duration of fever and days to recovery from neutropenia. Conventional doses of piperacillin/tazobactam may not offer adequate piperacillin exposure in febrile neutropenic patients. TDM provides useful feedback of dosing adequacy to guide dose optimization.
Publisher: BMJ
Date: 12-2022
DOI: 10.1136/BMJOPEN-2022-065401
Abstract: There has been renewed interest in the therapeutic use of bacteriophages (phages) however, standardised therapeutic protocols are lacking, and there is a paucity of rigorous clinical trial data assessing efficacy. We propose an open-label, single-arm trial investigating a standardised treatment and monitoring protocol for phage therapy. Patients included will have exhausted other therapeutic options for control of their infection and phage therapy will be administered under Australia’s Therapeutic Goods Administration Special Access Scheme. A phage product with high in vitro activity against the targeted pathogen(s) must be available in line with relevant regulatory requirements. We aim to recruit 50–100 patients over 5 years, from any public or private hospitals in Australia. The standardised protocol will specify clinical assessments and biological s ling at scheduled time points. The primary outcome is safety at day 29, assessed by the frequency of adverse events, and overseen by an independent Data Safety Monitoring Board. Secondary outcomes include long-term safety (frequency of adverse events until at least 6 months following phage therapy), and feasibility, measured as the proportion of participants with % of minimum data available for analysis. Additional endpoints assessed include clinical response, patient/guardian reported quality of life measures, phage pharmacokinetics, human host immune responses and microbiome analysis. All trial outcomes will be summarised and presented using standard descriptive statistics. Participant inclusion will be dependent on obtaining written informed consent from the patient or guardian. The trial protocol was approved by the Sydney Children’s Hospitals Network Human Research Ethics Committee in December 2021 (Reference 2021/ETH11861). In addition to publication in a peer-reviewed scientific journal, a lay summary of study outcomes will be made available for participants and the public on the Phage Australia website ( www.phageaustralia.org/ ). Registered on ANZCTR, 10 November 2021 (ACTRN12621001526864 WHO Universal Trial Number: U1111-1269-6000).
Publisher: Elsevier BV
Date: 08-2012
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 31-12-2020
Publisher: Oxford University Press (OUP)
Date: 07-2023
DOI: 10.1093/OFID/OFAD337
Abstract: The Combination Antibiotic Therapy for Methicillin-Resistant Staphylococcus aureus (CAMERA2) trial ceased recruitment in July 2018, noting that a higher proportion of patients in the intervention arm (combination therapy) developed acute kidney injury (AKI) compared to the standard therapy (monotherapy) arm. We analyzed the long-term outcomes of participants in CAMERA2 to understand the impact of combination antibiotic therapy and AKI. Trial sites obtained additional follow-up data. The primary outcome was all-cause mortality, censored at death or the date of last known follow-up. Secondary outcomes included kidney failure or a reduction in kidney function (a 40% reduction in estimated glomerular filtration rate to & mL/minute/1.73 m2). To determine independent predictors of mortality in this cohort, adjusted hazard ratios were calculated using a Cox proportional hazards regression model. This post hoc analysis included extended follow-up data for 260 patients. Overall, 123 of 260 (47%) of participants died, with a median population survival estimate of 3.4 years (235 deaths per 1000 person-years). Fifty-five patients died within 90 days after CAMERA2 trial randomization another 68 deaths occurred after day 90. Using univariable Cox proportional hazards regression, mortality was not associated with either the assigned treatment arm in CAMERA2 (hazard ratio [HR], 0.84 [95% confidence interval [CI], .59–1.19] P = .33) or experiencing an AKI (HR at 1 year, 1.04 [95% CI, .64–1.68] P = .88). In this cohort of patients hospitalized with methicillin-resistant S aureus bacteremia, we found no association between either treatment arm of the CAMERA2 trial or AKI (using CAMERA2 trial definition) and longer-term mortality.
Publisher: American Medical Association (AMA)
Date: 11-02-2020
Publisher: Future Medicine Ltd
Date: 02-2021
Abstract: The ability of influenza A virus to evolve, coupled with increasing antimicrobial resistance, could trigger an influenza pandemic with great morbidity and mortality. Much of the 1918 influenza pandemic mortality was likely due to bacterial coinfection, including Staphylococcus aureus pneumonia. S. aureus resists many antibiotics. The lack of new antibiotics suggests alternative antimicrobials, such as bacteriophages, are needed. Potential delivery routes for bacteriophage therapy (BT) include inhalation and intravenous injection. BT has recently been used successfully in compassionate access pulmonary infection cases. Phage lysins, enzymes that hydrolyze bacterial cell walls and which are bactericidal, are efficacious in animal pneumonia models. Clinical trials will be needed to determine whether BT can ameliorate disease in influenza and S. aureus coinfection.
Publisher: Elsevier BV
Date: 07-1997
Publisher: Elsevier BV
Date: 04-2001
DOI: 10.1016/S0168-1702(00)00244-6
Abstract: Two cell surface proteins (nectin-1/HveC and nectin-2/HveB) shown previously to serve as receptors for the entry of herpes simplex virus 1 (HSV-1) wild-type and/or mutant strains were found to serve also as receptors for HSV-1-induced cell fusion. Transfection with genomic DNA from a syncytial HSV-1 strain encoding wild-type gD resulted in fusion of Chinese hamster ovary (CHO) cells expressing nectin-1 but not of cells expressing nectin-2. In contrast, transfection with DNA from a related HSV-1 strain encoding the mutant Rid1 form of gD resulted in fusion of CHO cells expressing either receptor but not of control cells. These results are consistent with the ability of each receptor to mediate entry of viruses expressing wild-type or Rid1 gD and with results obtained previously with HVEM (HveA), a third HSV-l entry receptor. Undersulfation of GAGs in receptor-expressing cell lines predictably reduced susceptibility to HSV-l infection. In contrast, susceptibility to cell fusion mediated by HVEM or nectin-1 was not reduced. Undersulfation of GAGs partially inhibited cell fusion mediated by nectin-2. We conclude that HSV-1-induced cell fusion requires a gD-binding entry receptor, that ability of an HSV-1 strain to use HVEM, nectin-2 or nectin-1 for cell fusion depends on the allele of gD expressed and that GAGs may influence cell fusion, dependent on the gD-binding receptor used, but are less important for cell fusion mediated by HVEM, nectin-2 or nectin-l than for viral entry.
Publisher: Elsevier BV
Date: 11-2009
DOI: 10.1016/J.JFLM.2009.07.005
Abstract: Lemierre syndrome refers to necrotizing infections of the head due to Fusobacterium necrophorum and has been called the 'forgotten disease' due to its rarity in the antibiotic era. Recently, however, more cases have been documented in the literature suggesting that there has been an increase in incidence. A 10-year-old boy is reported who had a five-day history of ear infection, with the development of fever, drowsiness and ipsilateral neck swelling. Unexpected cardiac arrest occurred soon after medical assessment. At autopsy, right otitis media was demonstrated with extension of suppurative infection into subcutaneous tissues behind the ear and also into the extradural space at the lateral end of the petrous temporal bone. There was also septic thrombophlebitis of the adjacent sigmoid sinus, but no evidence of meningitis. This case demonstrates yet another infectious condition that may be associated with rapid deterioration and unexpected death in childhood. An autopsy approach to suspected sepsis in childhood is outlined.
Publisher: American Society for Microbiology
Date: 11-2017
DOI: 10.1128/AAC.00311-17
Abstract: Changes in the pharmacokinetics of piperacillin in febrile neutropenic patients have been reported to result in suboptimal exposures. This study aimed to develop a population pharmacokinetic model for piperacillin and perform dosing simulation to describe optimal dosing regimens for hematological malignancy patients with febrile neutropenia. Concentration-time data were obtained from previous prospective observational pharmacokinetic and interventional therapeutic drug monitoring studies. Nonparametric population pharmacokinetic analysis and Monte Carlo dosing simulations were performed with the Pmetrics package for R. A two-compartment model, with between-subject variability for clearance (CL), adequately described the data from 37 patients (21 males, age of 59 ± 12 years [means ± standard deviations] and weight of 77 ± 16 kg). Parameter estimates were CL of 18.0 ± 4.8 liters/h, volume of distribution of the central compartment of 14.3 ± 7.3 liters, rate constant for piperacillin distribution from the central to peripheral compartment of 1.40 ± 1.35 h −1 , and rate constant for piperacillin distribution from the peripheral to central compartment of 4.99 ± 7.81 h −1 . High creatinine clearance (CL CR ) was associated with reduced probability of target attainment (PTA). Extended and continuous infusion regimens achieved a high PTA of % for an unbound concentration of piperacillin remaining above the MIC ( fT MIC ) of 50%. Only continuous regimens achieved % PTA for 100% fT MIC when CL CR was high. The cumulative fraction of response (FTA, for fractional target attainment) was suboptimal ( %) for conventional regimens for both empirical and directed therapy considering 50% and 100% fT MIC . FTA was maximized with prolonged infusions. Overall, changes in piperacillin pharmacokinetics and the consequences on therapeutic dosing requirements appear similar to those observed in intensive care patients. Guidelines should address the altered dosing needs of febrile neutropenic patients exhibiting high CL CR or with known resumed infections from high-MIC bacteria.
Publisher: American Society for Microbiology
Date: 31-05-2023
DOI: 10.1128/JVI.00451-23
Publisher: Wiley
Date: 13-09-2023
DOI: 10.1111/IMJ.16226
Publisher: American Society for Microbiology
Date: 08-1995
DOI: 10.1128/JVI.69.8.5171-5176.1995
Abstract: Cells that express glycoprotein D (gD) of herpes simplex virus type 1 (HSV-1) resist infection by HSV-1 and HSV-2 because of interference with viral penetration. The results presented here show that both HSV-1 and HSV-2 gD can mediate interference and that various HSV-1 and HSV-2 strains differ in sensitivity to this interference. The relative degree of sensitivity was not necessarily dependent on whether the cell expressed the heterologous or homologous form of gD but rather on the properties of the virus. Marker transfer experiments revealed that the allele of gD expressed by the virus was a major determinant of sensitivity to interference. Amino acid substitutions in the most distal part of the gD ectodomain had a major effect, but substitutions solely in the cytoplasmic domain also influenced sensitivity to interference. In addition, evidence was obtained that another viral gene(s) in addition to the one encoding gD can influence sensitivity to interference. The results indicate that HSV-1 and HSV-2 gD share determinants required to mediate interference with infection by HSV of either serotype and that the pathway of HSV entry that is blocked by expression of cell-associated gD can be cleared or bypassed through subtle alterations in virion-associated proteins, particularly gD.
Publisher: Elsevier BV
Date: 07-2016
Publisher: Springer Science and Business Media LLC
Date: 18-03-2021
DOI: 10.1186/S13756-021-00915-W
Abstract: Antimicrobial resistance (AMR) represents a profound global health threat. Reducing AMR spread requires the identification of transmission pathways. The extent to which hospital wards represent a venue for substantial AMR transmission in low- and middle-income countries settings is poorly understood. Rectal swabs were obtained from adult male inpatients in a “Nightingale” model general medicine ward in Yangon, Myanmar. Resistome characteristics were characterised by metagenomic sequencing. AMR gene carriage was related to inter-patient distance (representing inter-patient interaction) using distance-based linear models. Clinical predictors of AMR patterns were identified through univariate and multivariate regression. Resistome similarity showed a weak but significant positive correlation with inter-patient distance (r = 0.12, p = 0.04). Nineteen AMR determinants contributed significantly to this relationship, including those encoding β-lactamase activity ( OXA-1 , NDM-7 adjusted p 0.003), trimethoprim resistance ( dfrA14 , adjusted p = 0.0495), and chlor henicol resistance ( catB3 , adjusted p = 0.002). Clinical traits of co-located patients carrying specific AMR genes were not random. Specifically, AMR genes that contributed to distance-resistome relationships ( OXA-1, catB3, dfrA14 ) mapped to tuberculosis patients, who were placed together according to ward policy. In contrast, patients with sepsis were not placed together, and carried AMR genes that were not spatially significant or consistent with shared antibiotic exposure. AMR dispersion patterns primarily reflect the placement of particular patients by their condition, rather than AMR transmission. The proportion of AMR determinants that varied with inter-patient distance was limited, suggesting that nosocomial transmission is a relatively minor contributor to population-level carriage.
Publisher: American Society for Microbiology
Date: 23-02-2023
DOI: 10.1128/AAC.01550-22
Abstract: Treatment of cytomegalovirus (CMV) infection in allogeneic hematopoietic stem cell transplantation (alloHCT) patients with ganciclovir is complicated by toxicity and resistance. This study aimed to develop an intravenous ganciclovir population pharmacokinetic model for post-alloHCT patients and to determine dosing regimens likely to achieve suggested therapeutic exposure targets.
Publisher: Wiley
Date: 02-12-2020
DOI: 10.1111/TID.13516
Abstract: Microsporum canis is a dermatophyte known to cause superficial skin infections. In immunocompromised patients, it can lead to invasive dermatophytosis. We present a case of biopsy‐proven left knee mycetoma caused by M canis in a renal transplant patient. Identification of M canis was achieved via sequencing of the internal transcribed spacer regions. Treatment involved surgical debridement, oral posaconazole, and reduction in immunosuppression. In addition, we provide a review of current literature on invasive M canis infections.
Publisher: American Society for Microbiology
Date: 27-06-2023
Publisher: Oxford University Press (OUP)
Date: 20-12-2016
DOI: 10.1093/JAC/DKW525
Abstract: Inappropriate antimicrobial use drives antimicrobial resistance and is a global public health problem. This study examined whether withholding antimicrobial susceptibilities in combination with interpretive comments on microbiological reports influenced the decision to inappropriately prescribe antibiotics in a controlled survey. Seventy junior doctors attending educational sessions were given one of two surveys describing four clinical case vignettes (scenarios) in which antimicrobial treatment was not indicated. They were asked to select their preferred treatment from multiple choices. In the scenarios labelled 'A', the laboratory report did not report antibiotic susceptibilities, but included comments from the microbiologist. In the scenarios labelled 'B', the laboratory report included full organism identification and susceptibility results without additional comments. For scenarios 1, 2 and 3 there was a significantly higher probability ( P < 0.01) that the doctor selected an answer involving antibiotic treatment if he/she received the 'B' version of the scenario where reports included antimicrobial susceptibilities, but no interpretive comments. This was significant in both interns and more senior doctors. In scenario 4, of which there were two versions, there was no difference seen in the answers between the groups given scenario A or B. The results of this survey suggest that withholding antimicrobial susceptibility results in combination with interpretive comments on microbiology reports significantly influences the decision of junior doctors to prescribe antibiotics in low-acuity outpatient setting scenarios (represented in scenarios 1-3), but not in inpatient scenarios (represented in scenario 4).
Publisher: Wiley
Date: 10-07-2018
DOI: 10.1111/JVH.12943
Abstract: In March 2016, the Australian government offered unrestricted access to direct-acting antiviral (DAA) therapy for chronic hepatitis C virus (HCV) to the entire population. This included prescription by any medical practitioner in consultation with specialists until sufficient experience was attained. We sought to determine the outcomes and experience over the first twelve months for the entire state of South Australia. We performed a prospective, observational study following outcomes of all treatments associated with the state's four main tertiary centres. A total of 1909 subjects initiating DAA therapy were included, representing an estimated 90% of all treatments in the state. Overall, SVR12 was 80.4% in all subjects intended for treatment and 95.7% in those completing treatment and follow-up. 14.2% were lost to follow-up (LTFU) and did not complete SVR12 testing. LTFU was independently associated with community treatment via remote consultation (OR 1.50, 95% CI 1.04-2.18, P = .03), prison-based treatment (OR 2.02, 95% CI 1.08-3.79, P = .03) and younger age (OR 0.98, 95% CI 0.97-0.99, P = .05). Of the 1534 subjects completing treatment and follow-up, decreased likelihood of SVR12 was associated with genotype 2 (OR 0.23, 95% CI 0.07-0.74, P = .01) and genotype 3 (OR 0.23, 95% CI 0.12-0.43, P ≤ .01). A significant decrease in treatment initiation was observed over the twelve-month period in conjunction with a shift from hospital to community-based treatment. Our findings support the high responses observed in clinical trials however, a significant gap exists in SVR12 in our real-world cohort due to LTFU. A declining treatment initiation rate and shift to community-based treatment highlight the need to explore additional strategies to identify, treat and follow-up remaining patients in order to achieve elimination targets.
Publisher: AMPCo
Date: 06-2013
DOI: 10.5694/MJA13.10025
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: American Society for Microbiology
Date: 06-2014
DOI: 10.1128/AAC.02340-14
Abstract: This study assessed the pharmacokinetics and dosing adequacy of piperacillin in febrile neutropenic patients after the first dose. Pharmacokinetic analysis was performed using noncompartmental methods. We observed an elevated volume of distribution (29.7 ± 8.0 liters [mean ± standard deviation]) and clearance (20.2 ± 7.5 liters/h) compared to data from other patient populations. Antibiotic exposure did not consistently result in therapeutic targets. We conclude that alternative dosing strategies guided by therapeutic drug monitoring may be required to optimize exposure.
Publisher: Elsevier BV
Date: 11-1996
DOI: 10.1016/S0092-8674(00)81363-X
Abstract: We identified and cloned a cellular mediator of herpes simplex virus (HSV) entry. Hamster and swine cells resistant to viral entry became susceptible upon expression of a human cDNA encoding this protein, designated HVEM (for herpesvirus entry mediator). HVEM was shown to mediate the entry of several wild-type HSV strains of both serotypes. Anti-HVEM antibodies and a soluble hybrid protein containing the HVEM ectodomain inhibited HVEM-dependent infection but not virus binding to cells. Mutations in the HSV envelope glycoprotein gD significantly reduced HVEM-mediated entry. The contribution of HVEM to HSV entry into human cells was demonstrable in activated T cells. HVEM, the first identified mediator of HSV entry, is a new member of the TNF/NGF receptor family.
Publisher: American Society for Microbiology
Date: 22-06-2023
Publisher: Elsevier BV
Date: 12-2021
DOI: 10.1016/J.JINF.2021.09.020
Abstract: Infection control is critical to safe hospital care. However, how bacteria within nosocomial environments relate to space utilisation and occupancy remains poorly understood. Our aim was to characterise the hospital microbiome in the context of the closure of a tertiary hospital and the opening of a new facility. Environmental swabs were collected from common and inpatient areas in the old and new hospitals during a 12-month transition period. Microbiota characteristics were determined by 16S rRNA gene sequencing and quantitative (q)PCR. Targeted assays were used to detect Methicillin-resistant Staphylococcus aureus (MRSA) and vanB-positive Vancomycin-Resistant Enterococci (VRE). The transition to full occupancy in the new facility was associated with an increase in bacterial load (inpatient areas, 3 months p = 0.001 common areas, 6 months p = 0.039) and a change in microbiota composition (baseline-12 months, PERMANOVA p = 0.002). These changes were characterised by an increase in human microbiota-associated taxa, including Acinetobacter and Veillonella. Closure of the existing facility was associated with a decrease in bacterial load (p = 0.040). Detection of MRSA did not differ significantly between sites. Occupancy is a major determinant of bacterial dispersion within hospital environments. Steady-state bacterial levels and microbiota composition provide a basis for assessment of infection control measures.
Publisher: Elsevier BV
Date: 07-2020
No related grants have been discovered for Morgyn Warner.