title: Dynamics of bovine intramammary infections due to coagulase-negative staphylococci on four farms.
abstract: The objectives of this study were to compare the impact of different coagulase-negative species (CNS) on udder health measured in terms of individual quarter milk somatic cell count (SCC) and duration of intramammary infection, and to get some insight into most likely routes of infection for different CNS species. This longitudinal observational study was performed on four farms that were sampled at 4-week intervals for a total of 12 visits each. Quarters infected with CNS were followed through time with milk samples being submitted for bacteriological culture and SCC determination. PCR amplification of the internal transcribed spacer region and sequencing of the sodA and rpoB genes were used for species allocation. Pulsed-field gel electrophoresis (PFGE) was performed to assess strain identity. The percentage of quarters affected per farm varied between 6 and 35%, with the most frequently isolated CNS species being Staphylococcus epidermidis, followed by Staph. simulans, Staph. chromogenes and Staph. haemolyticus. It was possible to follow 111 intramammary infections due to CNS through time. Duration of infection had a mean of 188 d and was not significantly different between CNS species. Geometric mean quarter SCC overall was 132 000 cells/ml and was also not significantly different between CNS species. Despite the possibility of a different epidemiology of infection, the impact in terms of udder health seems to be similar for different CNS species.
authors.affiliation: CIISA/Faculdade de Medicina Veterinária, Universidade de Lisboa. Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Bexiga
authors.affiliation: Centro de Recursos Microbiológicos, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa, Caparica, Portugal.
authors.forename: Márcia G
authors.initials: MG
authors.lastname: Rato
authors.affiliation: CIISA/Faculdade de Medicina Veterinária, Universidade de Lisboa. Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Abdelhak
authors.initials: A
authors.lastname: Lemsaddek
authors.affiliation: CIISA/Faculdade de Medicina Veterinária, Universidade de Lisboa. Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Semedo-Lemsaddek
authors.affiliation: CIISA/Faculdade de Medicina Veterinária, Universidade de Lisboa. Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Carneiro
authors.affiliation: VetAgro Sup Campus Vétérinaire de Lyon, 1 Avenue Bourgelat 69280 Marcy L'Etoile, France.
authors.forename: Helena
authors.initials: H
authors.lastname: Pereira
authors.affiliation: Scottish Centre for Production Animal Health and Food Safety, Large Animal Clinical Sciences and Public Health, School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Bearsden, Glasgow, G61 1QH, Scotland.
authors.forename: Dominic J
authors.initials: DJ
authors.lastname: Mellor
authors.affiliation: Scottish Centre for Production Animal Health and Food Safety, Large Animal Clinical Sciences and Public Health, School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Bearsden, Glasgow, G61 1QH, Scotland.
authors.forename: Kathryn A
authors.initials: KA
authors.lastname: Ellis
authors.affiliation: CIISA/Faculdade de Medicina Veterinária, Universidade de Lisboa. Avenida da Universidade Técnica, 1300-477 Lisboa, Portugal.
authors.forename: Cristina L
authors.initials: CL
authors.lastname: Vilela
mesh_terms: D000818:Animals; D002417:Cattle; D002452:Cell Count; D003030:Coagulase / Q000032:analysis*; D004269:DNA, Bacterial / Q000032:analysis; D003612:Dairying; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008321:Mammary Glands, Animal / Q000382:microbiology; D008414:Mastitis, Bovine / Q000382:microbiology*; D008892:Milk / Q000166:cytology; D016133:Polymerase Chain Reaction; D013203:Staphylococcal Infections / Q000382:microbiology / Q000662:veterinary*; D013210:Staphylococcus / Q000145:classification* / Q000201:enzymology / Q000235:genetics; D013997:Time Factors
chemical_list: D003030:Coagulase; D004269:DNA, Bacterial