ORCID Profile
0000-0003-1386-6527
Current Organisation
University of Adelaide
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Publisher: MDPI AG
Date: 11-05-2023
DOI: 10.3390/ANTIBIOTICS12050895
Abstract: The similarity of commensal Escherichia coli isolated from healthy cattle to antimicrobial-resistant bacteria causing extraintestinal infections in humans is not fully understood. In this study, we used a bioinformatics approach based on whole genome sequencing data to determine the genetic characteristics and phylogenetic relationships among faecal Escherichia coli isolates from beef cattle (n = 37) from a single feedlot in comparison to previously analysed pig faecal (n = 45), poultry extraintestinal (n = 19), and human extraintestinal E. coli isolates (n = 40) from three previous Australian studies. Most beef cattle and pig isolates belonged to E. coli phylogroups A and B1, whereas most avian and human isolates belonged to B2 and D, although a single human extraintestinal isolate belonged to phylogenetic group A and sequence type (ST) 10. The most common E. coli sequence types (STs) included ST10 for beef cattle, ST361 for pig, ST117 for poultry, and ST73 for human isolates. Extended-spectrum and AmpC β-lactamase genes were identified in seven out of thirty-seven (18.9%) beef cattle isolates. The most common plasmid replicons identified were IncFIB (AP001918), followed by IncFII, Col156, and IncX1. The results confirm that feedlot cattle isolates examined in this study represent a reduced risk to human and environmental health with regard to being a source of antimicrobial-resistant E. coli of clinical importance.
Publisher: University of Mosul
Date: 28-01-2019
Publisher: MDPI AG
Date: 28-06-2023
DOI: 10.3390/ANTIBIOTICS12071122
Abstract: The extent of similarity between E. faecium strains found in healthy feedlot beef cattle and those causing extraintestinal infections in humans is not yet fully understood. This study used whole-genome sequencing to analyse the antimicrobial resistance profile of E. faecium isolated from beef cattle (n = 59) at a single feedlot and compared them to previously reported Australian isolates obtained from pig (n = 60) and meat chicken caecal s les (n = 8), as well as human sepsis cases (n = 302). The E. faecium isolated from beef cattle and other food animal sources neither carried vanA/vanB responsible for vancomycin nor possessed gyrA arC and liaR/liaS gene mutations associated with high-level fluoroquinolone and daptomycin resistance, respectively. A small proportion (7.6%) of human isolates clustered with beef cattle and pig isolates, including a few isolates belonging to the same sequence types ST22 (one beef cattle, one pig, and two human isolates), ST32 (eight beef cattle and one human isolate), and ST327 (two beef cattle and one human isolate), suggesting common origins. This provides further evidence that these clonal lineages may have broader host range but are unrelated to the typical hospital-adapted human strains belonging to clonal complex 17, significant proportions of which contain vanA/vanB and liaR/liaS. Additionally, none of the human isolates belonging to these STs contained resistance genes to WHO critically important antimicrobials. The results confirm that most E. faecium isolated from beef cattle in this study do not pose a significant risk for resistance to critically important antimicrobials and are not associated with current human septic infections.
Publisher: University of Mosul
Date: 28-06-2013
Publisher: MDPI AG
Date: 06-10-2022
DOI: 10.3390/ANI12192690
Abstract: Enterococcus faecium are commensal bacteria inhabiting the gastrointestinal tract of animals and humans and an important cause of drug-resistant nosocomial infections. This longitudinal study aimed to determine whether changes in the antimicrobial resistance (AMR) phenotype and genotype occurred among Enterococcus spp. isolated from cattle rectal s les obtained at the entry to and exit from an Australian feedlot. The s les obtained at the feedlot induction yielded enterococci (104/150 69.3%), speciated as E. hirae (90/104 86.5%), E. faecium (9/104 8.7%), E. mundtii (3/104 2.9%), E. durans, and E. casseliflavus (1/104 1.0% each). AMR was observed to lincomycin (63/104 60.6%), daptomycin (26/104 25.0%), nitrofurantoin (9/104 8.7%), ciprofloxacin (7/104 6.7%), tetracycline (5/104 4.8%), tigecycline (4/104 3.9%), and quinupristin/dalfopristin (3/104 2.9%). From the rectal swab s les collected at the abattoir from the same animals (i.e., the feedlot exit), the enterococci recovery was significantly higher (144/150 96.0%), with a marked shift in species distribution dominated by E. faecium (117/144 81.3%). However, the prevalence of AMR to in idual antimicrobials remained largely static between the entry and exit except for the increased resistance to nitrofurantoin (77/144 53.5%) and quinupristin/dalfopristin (26/144 18.1%). Overall, 13 AMR genes were observed among the 62 E. faecium isolates. These included aac(6′)Ii, aac(6′)-Iid, and ant(6)-Ia (aminoglycosides) eatAv, lnu(G), vat(E), msr(C), and erm(B) (macrolides, lincosamides, and streptogramins) efmA (fluoroquinolones) and tet(45), tet(L), tet(M), and tet(S) (tetracyclines). The results confirm the presence of fluoroquinolone- and streptogramin-resistant enterococci in cattle faeces at the feedlot entry in the absence of antimicrobial selection pressure. E. faecium, exhibiting increased nitrofurantoin resistance, became the dominant Enterococcus spp. during the feeding period.
Publisher: MDPI AG
Date: 21-08-2023
DOI: 10.3390/ANI13162684
Abstract: There was an error in the original publication [...]
Publisher: Springer Science and Business Media LLC
Date: 17-11-2011
DOI: 10.1007/S11626-010-9348-5
Abstract: A new cell line, Asian sea bass brain (ASBB), was derived from the brain tissue of Asian sea bass Lates calcarifer. This cell line was maintained in Leibovitz L-15 media supplemented with 10% fetal bovine serum (FBS). The ASBB cell line was subcultured more than 60 times over a period of 15 mo. The ASBB cell line consists predominantly of fibroblastic-like cells and was able to grow at temperatures between 20°C and 30°C with an optimum temperature of 25°C. The growth rate of these cells increased as the proportion of FBS increased from 2% to 20% at 25°C with optimum growth at the concentrations of 10% or 15% FBS. Polymerase chain reaction products were obtained from ASBB cells and tissues of sea bass with primer sets of microsatellite markers of sea bass. An isolate of piscine nodavirus from juveniles of marine fish species tested positive by IQ2000 kit for viral nervous necrosis detection and was examined for its infectivity to a fish cell line of ASBB. A marine fish betanodavirus was tested to determine the susceptibility of this new cell line in comparison with commercial highly permissive SSN-1 cells. The ASBB cell line was found to be susceptible to nodavirus (RGNNV genotype), and the infection was confirmed by comparison cytopathic effect (CPE) with commercial SSN-1 and reverse transcriptase-polymerase chain reaction. A nodavirus was further elucidated by electron microscopy, and the virus tested was shown to induce CPE on ASBB cells with significant high titer. This suggests that the ASBB cell line has good potential for the isolation of fish viruses.
Publisher: MDPI AG
Date: 31-08-2022
DOI: 10.3390/ANI12172256
Abstract: This study investigated the antimicrobial resistance (AMR) profile of fecal Escherichia coli isolates from beef cattle (n = 150) at entry and exit from an Australian feedlot. S le plating on MacConkey agar and Brilliance ESBL agar differentiated generic from extended-spectrum β-lactamase (ESBL)-producing E. coli, respectively. Resistance profiles were determined by minimum inhibitory concentration (MIC) testing and further analyzed by whole-genome sequencing (WGS). At entry, the prevalence of antimicrobial resistance to amoxicillin/clavulanic acid, icillin, streptomycin, and trimethoprim/sulfamethoxazole was very low (0.7%, each). At the exit, the resistance prevalence was moderate to tetracycline (17.8%) and low to icillin (5.4%), streptomycin (4.7%), and sulfisoxazole (3.9%). The most common AMR genes observed in phenotypically resistant isolates were tet(B) (43.2%), aph(3″)-Ib and aph(6)-Id (32.4%), blaTEM-1B, and sul2 (24.3%, each), which are responsible for resistance to tetracyclines, aminoglycosides, β-lactams, and sulfonamides, respectively. The ESBL-producing E. coli were recovered from one s le (0.7%) obtained at entry and six s les (4.0%) at the exit. The ESBL-producing E. coli harbored blaTEM (29.7%), blaCTX m(13.5%), and blaCMY (5.4%). The resistance phenotypes were highly correlated with resistance genotypes (r ≥ 0.85: p 0.05). This study demonstrated that E. coli isolated from feedlot beef cattle can harbour AMR genes, but the low incidence of medically important resistance reflected the prudent antimicrobial use in the Australian industry.
Start Date: 2017
End Date: 2017
Funder: U.S. Civilian Research & Development Foundation (dba CRDF Global)
View Funded ActivityStart Date: 2011
End Date: 2011
Funder: UPM/ SCHOOL OF GRADUATE STUDIES
View Funded ActivityStart Date: 2007
End Date: 2010
Funder: Universiti Putra Malaysia
View Funded Activity