학술논문
Genetic and Phenotypic Characterization of Subclinical Mastitis-Causing Multidrug-Resistant Staphylococcus aureus .
Document Type
Academic Journal
Author
Silva ATF; Department of Veterinary Medicine, Federal Rural University of Pernambuco, Recife 52171-900, Brazil.; Gonçalves JL; Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.; Dantas STA; Department of Chemical and Biological Sciences, Institute of Biosciences, São Paulo State University, Botucatu 18618-689, Brazil.; Department of Animal Sciences, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Pirassununga 13635-900, Brazil.; Rall VLM; Department of Chemical and Biological Sciences, Institute of Biosciences, São Paulo State University, Botucatu 18618-689, Brazil.; de Oliveira PRF; Department of Veterinary Medicine, Federal Rural University of Pernambuco, Recife 52171-900, Brazil.; Dos Santos MV; Department of Animal Sciences, School of Veterinary Medicine and Animal Sciences, University of São Paulo, Pirassununga 13635-900, Brazil.; Peixoto RM; Federal Institute of Education, Science and Technology of Sertão Pernambucano, Petrolina 56316-686, Brazil.; Mota RA; Department of Veterinary Medicine, Federal Rural University of Pernambuco, Recife 52171-900, Brazil.
Source
Publisher: MDPI AG Country of Publication: Switzerland NLM ID: 101637404 Publication Model: Electronic Cited Medium: Print ISSN: 2079-6382 (Print) Linking ISSN: 20796382 NLM ISO Abbreviation: Antibiotics (Basel) Subsets: PubMed not MEDLINE
Subject
Language
English
ISSN
2079-6382
Abstract
The core objective of this study was to genetically and phenotypically characterize subclinical mastitis-causing multidrug-resistant Staphylococcus aureus (MDRSA). In addition, risk factors associated with subclinical mastitis caused by MDRSA were investigated. Bacterial cultures were performed on 2120 mammary quarters, 40 swabs of milk utensils, 5 bulk tank milk samples, and 11 nostril and 11 hand swabs from milkers from five dairy farms. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was conducted for S. aureus identification. Antimicrobial resistance was screened phenotypically using the disk diffusion test in all S. aureus isolates. A biofilm formation assay; detection of genes associated with beta-lactam resistance, efflux pump, and biofilm formation; and pulsed-field gel electrophoresis (PFGE) were performed in all MDRSA isolates. Multi-locus sequence typing (MLST) was carried out in cefoxitin-resistant MDRSA isolates. A total of 188 S. aureus isolates from milk as well as two from milking utensils and one from bulk tank milk were identified. Most of the isolates (92.7%; 177 of 191) showed beta-lactam resistance, and 7% (14 of 191) were MDRSA. Interestingly, 36% (5 of 14) of MDRSA isolates were cefoxitin-resistant, but none carried mecA or mecC genes. Based on PFGE results, it was observed that S. aureus strains were more likely to be unique to a specific herd. Two clonal complexes were identified, CC97 (ST126; commonly livestock-associated) and CC1 (ST7440; usually community-associated). To the best of our knowledge, this is the first report of ST7440 isolated from bovine mastitis in Brazil. The risk factor results underscored the importance of considering parity, stage of lactation, SCC, milk production, and herd size when studying the risk of subclinical mastitis and antimicrobial resistance in S. aureus . Thus, to implement effective strategies to prevent subclinical mastitis in dairy herds and to minimize MDRSA spread, it is important to understand MDRSA strains' distribution and their antimicrobial resistance profile.