title: Genotypic and phenotypic characterization of Staphylococcus aureus causing persistent and nonpersistent subclinical bovine intramammary infections during lactation or the dry period.
abstract: Staphylococcus aureus is a significant pathogen frequently causing persistent intramammary infections (IMI) in dairy cows. We compared some genotypic and phenotypic characteristics of 285 strains collected from quarter milk samples from cows with persistent and nonpersistent subclinical IMI across Canada. Variable number of tandem repeats typing was used to infer the persistence of the same S. aureus strain in 3 consecutive quarter milk samples collected at intervals of 3 wk during lactation or before and after dry-off. All first isolates of the series were used as the representative strains from persistent IMI and were compared with nonpersistent strains for the presence of genes seg, sen, sec, and tst as well as by spa typing. Biofilm production in vitro and hld-RNAIII expression levels were also quantified. The gene seg was associated with a reduction in the likelihood of the bacteria to cause a persistent IMI during lactation. Strains persisting through the dry period produced significantly more biofilm in vitro than strains that do not persist after calving. Also, we showed that strains expressing more hld were more likely to be nonpersistent during either lactation or through the dry period. Three spa types were predominant (t529, t267, and a novel type: t13401). In the strains studied, the spa type tbl 2645 was the most frequent, and 97.0% of the strains of this spa type carried both sen and seg. Strains from the spa type tbl 2645 were less likely to cause a persistent IMI in the dry period. Most (86.7%) of the strains of the novel spa type (t13401) were negative for seg, sen, or both and produced significantly more biofilm in vitro than tbl 2645 and t267. The present study expanded our current knowledge on the genotypic and phenotypic traits of S. aureus strains recovered from persistent and nonpersistent IMI in Canada.
authors.affiliation: Centre d'Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1K 2R1; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: K A
authors.initials: KA
authors.lastname: Veh
authors.affiliation: Departmento de Bioquimica e Biologia Molecular, Universidade Federal de Viçosa, Viçosa 36570-000, MG, Brazil.
authors.forename: R C
authors.initials: RC
authors.lastname: Klein
authors.affiliation: Centre d'Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1K 2R1; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: C
authors.initials: C
authors.lastname: Ster
authors.affiliation: Centre for Veterinary Epidemiological Research, University of Prince Edward Island, Charlottetown, PE, Canada C1A 4P3; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: G
authors.initials: G
authors.lastname: Keefe
authors.affiliation: Dairy and Swine Research and Development Centre, Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada J1M 0C8; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: P
authors.initials: P
authors.lastname: Lacasse
authors.affiliation: Département de Pathologie et Microbiologie and Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: D
authors.initials: D
authors.lastname: Scholl
authors.affiliation: Département de Pathologie et Microbiologie and Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: J-P
authors.initials: JP
authors.lastname: Roy
authors.affiliation: Département de Pathologie et Microbiologie and Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: D
authors.initials: D
authors.lastname: Haine
authors.affiliation: Département de Pathologie et Microbiologie and Département de Sciences Cliniques, Faculté de Médecine Vétérinaire, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: S
authors.initials: S
authors.lastname: Dufour
authors.affiliation: Centre d'Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1K 2R1; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6.
authors.forename: B G
authors.initials: BG
authors.lastname: Talbot
authors.affiliation: Departmento de Bioquimica e Biologia Molecular, Universidade Federal de Viçosa, Viçosa 36570-000, MG, Brazil. Electronic address: abribon@ufv.br.
authors.forename: A O B
authors.initials: AO
authors.lastname: Ribon
authors.affiliation: Centre d'Étude et de Valorisation de la Diversité Microbienne (CEVDM), Département de Biologie, Faculté des Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada J1K 2R1; Canadian Bovine Mastitis and Milk Quality Research Network, C.P. 5000, St-Hyacinthe, QC, Canada J2S 7C6. Electronic address: abribon@ufv.br.
authors.forename: F
authors.initials: F
authors.lastname: Malouin
mesh_terms: D000818:Animals; D058345:Asymptomatic Infections; D018441:Biofilms / Q000254:growth & development; D002170:Canada; D002417:Cattle; D002418:Cattle Diseases / Q000382:microbiology*; D004269:DNA, Bacterial / Q000302:isolation & purification; D005260:Female; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D007774:Lactation; D008414:Mastitis, Bovine / Q000382:microbiology*; D008892:Milk / Q000382:microbiology*; D018598:Minisatellite Repeats; D010641:Phenotype; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology
chemical_list: D004269:DNA, Bacterial
keywords: Staphylococcus aureus; dairy cow; mastitis; persistence; subclinical