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Sequencing Independent Molecular Typing of Staphylococcus aureus Isolates: Approach for Infection Control and Clonal Characterization. Microbiol Spectr 2022; 10:e0181721. [PMID: 35138156 PMCID: PMC8826877 DOI: 10.1128/spectrum.01817-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Staphylococcus aureus is a major bacterial human pathogen that causes a wide variety of clinical manifestations. The main aim of the presented study was to determine and optimize a novel sequencing independent approach that enables molecular typing of S. aureus isolates and elucidates the transmission of emergent clones between patients. In total, 987 S. aureus isolates including both methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates were used to evaluate the novel typing approach combining high-resolution melting (HRM) analysis of multilocus sequence typing (MLST) genes (mini-MLST) and spa gene (spa-HRM). The novel approach's discriminatory ability was evaluated by whole-genome sequencing (WGS). The clonal relatedness of tested isolates was set by the BURP and BURST approach using spa and MLST data, respectively. Mini-MLST classified the S. aureus isolates into 38 clusters, followed by spa-HRM classifying the isolates into 101 clusters. The WGS proved HRM-based methods to effectively differentiate between related S. aureus isolates. Visualizing evolutionary relationships among different spa-types provided by the BURP algorithm showed comparable results to MLST/mini-MLST clonal clusters. We proved that the combination of mini-MLST and spa-HRM is rapid, reproducible, and cost-efficient. In addition to high discriminatory ability, the correlation between spa evolutionary relationships and mini-MLST clustering allows the variability in population structure to be monitored. IMPORTANCE Rapid and cost-effective molecular typing tools for Staphylococcus aureus epidemiological applications such as transmission tracking, source attribution and outbreak investigations are highly desirable. High-resolution melting based methods are effective alternative to those based on sequencing. Their good reproducibility and easy performance allow prospective typing of large set of isolates while reaching great discriminatory power. In this study, we established a new epidemiological approach to S. aureus typing. This scheme has the potential to greatly improve epidemiological investigations of S. aureus.
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Sahibzada S, Pang S, Hernández-Jover M, Jordan D, Abraham S, O'Dea M, Heller J. Prevalence and antimicrobial resistance of MRSA across different pig age groups in an intensive pig production system in Australia. Zoonoses Public Health 2020; 67:576-586. [PMID: 32458580 DOI: 10.1111/zph.12721] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 11/21/2019] [Accepted: 04/14/2020] [Indexed: 01/22/2023]
Abstract
This observational study aimed to determine MRSA prevalence using strain-specific real-time PCR at the pig level, stratified by age groupings, within a pig enterprise. A total of 658 samples were collected from individual pigs (n = 618) and the piggery environment (n = 40), distributed amongst five different pig age groups. Presumptive MRSA isolates were confirmed by the presence of mecA, and MALDI-TOF was performed for species verification. All isolates were tested against 18 different antimicrobials. MRSA was isolated from 75.2% (95% CI 71.8-78.6) of samples collected from pigs, and 71% of the MRSA isolates from this source were identified as community-associated (CA)-MRSA ST93, while the remainder were livestock-associated (LA)-MRSA ST398. Amongst environmental isolates, 80% (CI 64.3-95.7) were ST93 and the remainder ST398. All MRSA isolates from pigs and the environment were susceptible to ciprofloxacin, gentamicin, linezolid, mupirocin, rifampicin, sulfamethoxazole-trimethoprim, teicoplanin and vancomycin. Phenotypic rates of resistance were penicillin (100%), clindamycin (97.6%), erythromycin (96.3%), ceftiofur (93.7%), chloramphenicol (81.2%), tetracycline (63.1%) and amoxicillin-clavulanate (63.9%). A low prevalence of resistance (9.2%) was observed against neomycin and quinupristin-dalfopristin. The probability of MRSA carriage in dry sows (42.2%) was found to be significantly lower (p < .001) when compared to other age groups: farrowing sows (76.8%, RR1.82), weaners (97.8%, RR 2.32), growers (94.2%, RR 2.23) and finishers (98.3%, RR 2.33). Amongst different production age groups, a significant difference was also found in antimicrobial resistance for amoxicillin-clavulanate, neomycin, chloramphenicol and tetracycline. Using the RT-PCR assay adopted in this study, filtering of highly prevalent ST93 and non-ST93 isolates was performed at high throughput and low cost. In conclusion, this study found that weaner pigs presented a higher risk for CA-MRSA and antimicrobial resistance compared to other age groups. These findings have major implications for how investigations of MRSA outbreaks should be approached under the One-Health context.
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Affiliation(s)
- Shafi Sahibzada
- Antimicrobial Resistance and Infectious Diseases Laboratory, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia.,School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, Australia
| | - Stanley Pang
- Antimicrobial Resistance and Infectious Diseases Laboratory, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia.,PathWest Laboratory Medicine - WA, Fiona Stanley Hospital, Murdoch, Australia
| | - Marta Hernández-Jover
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, Australia
| | - David Jordan
- New South Wales Department of Primary Industries, Wollongbar, NSW, Australia
| | - Sam Abraham
- Antimicrobial Resistance and Infectious Diseases Laboratory, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| | - Mark O'Dea
- Antimicrobial Resistance and Infectious Diseases Laboratory, College of Science, Health, Engineering and Education, Murdoch University, Murdoch, WA, Australia
| | - Jane Heller
- School of Animal and Veterinary Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia.,Graham Centre for Agricultural Innovation, Wagga Wagga, NSW, Australia
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