title: Methicillin-Resistant Staphylococcus aureus from Brazilian Dairy Farms and Identification of Novel Sequence Types.
abstract: The aim of this study was to investigate the phenotypic and genotypic diversity and anti-microbial resistance among staphylococci of dairy herds that originated from Paraiba State, north-eastern Brazil, a region where such studies are rare. Milk samples (n = 552) were collected from 15 dairy farms. Isolates were evaluated for anti-microbial susceptibility by Kirby-Bauer disc diffusion method. Confirmation of methicillin-resistant Staphylococcus aureus (MRSA) was performed using multiplex PCR targeting mecA and nuc genes in addition to phenotypic assay based on PBP-2a latex agglutination. Clonal relatedness of isolates was determined by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) genotyping. Staphylococci were detected in 269 (49%) of the samples. Among these, 65 (24%) were S. aureus. The remaining 204 isolates were either coagulase-negative staphylococci (n = 188; 70%) or coagulase positive other than S. aureus (n = 16; 6%). Staphylococci were cultured in seven (35%) of the 20 hand swab samples, from which five isolates were S. aureus. The isolates were most commonly resistant against penicillin (43%), ampicillin (38%) and oxacillin (27%). The gene mecA was detected in 21 S. aureus from milk and in one isolate from a milker's hand. None of the isolates were resistant to vancomycin. PFGE findings showed high clonal diversity among the isolates. Based on MLST, we identified a total of 11 different sequence types (STs 1, 5, 6, 83, 97, 126, 1583, 1622, 1623, 1624 and 1625) with four novel STs (ST1622-ST1625). The findings show that MRSA is prevalent in milk from semi-extensive dairy cows in north-eastern Brazil, and further investigation on its extent in various types of milk production systems and the farm-to-table continuum is warranted.
authors.affiliation: Department of Animal Science, Centre for Agricultural Sciences, Federal University of Paraiba, Areia, PB, Brazil.|Veterinary Public Health and Biotechnology Global Consortium (VPH-Biotec), The Ohio State University, Columbus, OH, USA.
authors.forename: C J B
authors.initials: CJ
authors.lastname: Oliveira
authors.affiliation: Department of Preventive Veterinary Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA.
authors.forename: N
authors.initials: N
authors.lastname: Tiao
authors.affiliation: Department of Animal Science, Centre for Agricultural Sciences, Federal University of Paraiba, Areia, PB, Brazil.
authors.forename: F G C
authors.initials: FG
authors.lastname: de Sousa
authors.affiliation: Department of Animal Science, Centre for Agricultural Sciences, Federal University of Paraiba, Areia, PB, Brazil.
authors.forename: J F P
authors.initials: JF
authors.lastname: de Moura
authors.affiliation: Department of Pharmacy, Center for Health Sciences, Federal University of Paraiba, João Pessoa, PB, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Santos Filho
authors.affiliation: Veterinary Public Health and Biotechnology Global Consortium (VPH-Biotec), The Ohio State University, Columbus, OH, USA.|Department of Preventive Veterinary Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA.
authors.forename: W A
authors.initials: WA
authors.lastname: Gebreyes
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics; D044822:Biodiversity; D001938:Brazil / Q000453:epidemiology; D002417:Cattle; D003612:Dairying; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D005506:Food Contamination; D005516:Food Microbiology; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D008836:Micrococcal Nuclease / Q000235:genetics; D008892:Milk / Q000382:microbiology*; D058885:Multilocus Sequence Typing; D046915:Penicillin-Binding Proteins / Q000235:genetics; D010641:Phenotype; D016133:Polymerase Chain Reaction; D013202:Staphylococcal Food Poisoning / Q000453:epidemiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D046915:Penicillin-Binding Proteins; C487789:mecA protein, Staphylococcus aureus; C074002:nuc protein, staphylococcus; D008836:Micrococcal Nuclease
keywords: Methicillin-resistant Staphylococcus aureus; milk; oxacillin resistance; oxacillin resistant Staphylococcus aureus