title: Bovine Staphylococcus aureus: Subtyping, evolution, and zoonotic transfer.
abstract: Staphylococcus aureus is globally one of the most important pathogens causing contagious mastitis in cattle. Previous studies using ribosomal spacer (RS)-PCR, however, demonstrated in Swiss cows that Staph. aureus isolated from bovine intramammary infections are genetically heterogeneous, with Staph. aureus genotype B (GTB) and GTC being the most prominent genotypes. Furthermore, Staph. aureus GTB was found to be contagious, whereas Staph. aureus GTC and all the remaining genotypes were involved in individual cow disease. In addition to RS-PCR, other methods for subtyping Staph. aureus are known, including spa typing and multilocus sequence typing (MLST). They are based on sequencing the spa and various housekeeping genes, respectively. The aim of the present study was to compare the 3 analytic methods using 456 strains of Staph. aureus isolated from milk of bovine intramammary infections and bulk tanks obtained from 12 European countries. Furthermore, the phylogeny of animal Staph. aureus was inferred and the zoonotic transfer of Staph. aureus between cattle and humans was studied. The analyzed strains could be grouped into 6 genotypic clusters, with CLB, CLC, and CLR being the most prominent ones. Comparing the 3 subtyping methods, RS-PCR showed the highest resolution, followed by spa typing and MLST. We found associations among the methods but in many cases they were unsatisfactory except for CLB and CLC. Cluster CLB was positive for clonal complex (CC)8 in 99% of the cases and typically positive for t2953; it is the cattle-adapted form of CC8. Cluster CLC was always positive for tbl 2645 and typically positive for CC705. For CLR and the remaining subtypes, links among the 3 methods were generally poor. Bovine Staph. aureus is highly clonal and a few clones predominate. Animal Staph. aureus always evolve from human strains, such that every human strain may be the ancestor of a novel animal-adapted strain. The zoonotic transfer of IMI- and milk-associated strains of Staph. aureus between cattle and humans seems to be very limited and different hosts are not considered as a source for mutual, spontaneous infections. Spillover events, however, may happen.
authors.affiliation: Agroscope, Institute for Food Sciences (IFS), Schwarzenburgstrasse 161, 3003 Berne, Switzerland.
authors.forename: R
authors.initials: R
authors.lastname: Boss
authors.affiliation: Agroscope, Institute for Food Sciences (IFS), Schwarzenburgstrasse 161, 3003 Berne, Switzerland; Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Berne, Bremgartenstrasse 109a, P.O. Box 8466, 3001 Berne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Cosandey
authors.affiliation: Istituto Zooprofilattico Sperimentale della Lombardia e dell'Emilia Romagna, Via Einstein, 26900 Lodi, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Luini
authors.affiliation: Department of Bacteriology, National Veterinary Institute, SE-751 89 Uppsala, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Artursson
authors.affiliation: Bacteriology, Department of Infectious Diseases, Faculty of Veterinary Medicine, University of Liège, Avenue de Cureghem 6, 4000 Liège, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Bardiau
authors.affiliation: Milchprüfring Baden-Württemberg e. V., Marie-Curie-Strasse 19, 73230 Kirchheim/Teck, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Breitenwieser
authors.affiliation: Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Berne, Bremgartenstrasse 109a, P.O. Box 8466, 3001 Berne, Switzerland.
authors.forename: E
authors.initials: E
authors.lastname: Hehenberger
authors.affiliation: GD Animal Health, Arnsbergstraat 7, PO Box 9, 7400 AA Deventer, the Netherlands.
authors.forename: Th
authors.initials: T
authors.lastname: Lam
authors.affiliation: Carinthian Institute for Veterinary Disease Control, Kirchengasse 43, 9020 Klagenfurt, Austria.
authors.forename: M
authors.initials: M
authors.lastname: Mansfeld
authors.affiliation: Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Berne, Bremgartenstrasse 109a, P.O. Box 8466, 3001 Berne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Michel
authors.affiliation: Animal Health Organisation Upper Austria, Bahnhofplatz 1, 4021 Linz, Austria.
authors.forename: G
authors.initials: G
authors.lastname: Mösslacher
authors.affiliation: Agroscope, Institute for Food Sciences (IFS), Schwarzenburgstrasse 161, 3003 Berne, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Naskova
authors.affiliation: Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, Ullevalsvn 72, PO Box 8146 Dep, N-0033 Oslo, Norway.
authors.forename: S
authors.initials: S
authors.lastname: Nelson
authors.affiliation: Ambulatory Clinic for Large Animals, University of Ljubljana, Veterinary Faculty, Gerbičeva ul. 60, 1000 Ljubljana, Slovenia.
authors.forename: O
authors.initials: O
authors.lastname: Podpečan
authors.affiliation: Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Berne, Bremgartenstrasse 109a, P.O. Box 8466, 3001 Berne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Raemy
authors.affiliation: School of Veterinary Medicine, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: E
authors.initials: E
authors.lastname: Ryan
authors.affiliation: Veterinary Clinic of Haute Auvergne, Allauzier, 15100 Saint Flour, France.
authors.forename: O
authors.initials: O
authors.lastname: Salat
authors.affiliation: Federal Institute for Alpine Dairying BAM, 6200 Jenbach, Austria.
authors.forename: P
authors.initials: P
authors.lastname: Zangerl
authors.affiliation: Clinic for Ruminants, Department of Clinical Veterinary Medicine, Vetsuisse-Faculty, University of Berne, Bremgartenstrasse 109a, P.O. Box 8466, 3001 Berne, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Steiner
authors.affiliation: Agroscope, Institute for Food Sciences (IFS), Schwarzenburgstrasse 161, 3003 Berne, Switzerland. Electronic address: hansulrich.graber@agroscope.admin.ch.
authors.forename: H U
authors.initials: HU
authors.lastname: Graber
mesh_terms: D000818:Animals; D001483:Base Sequence; D002417:Cattle; D005060:Europe; D005260:Female; D005838:Genotype; D006801:Humans; D008414:Mastitis, Bovine / Q000382:microbiology*; D008892:Milk / Q000382:microbiology*; D008969:Molecular Sequence Data; D058885:Multilocus Sequence Typing / Q000662:veterinary; D010802:Phylogeny; D017422:Sequence Analysis, DNA / Q000662:veterinary; D013203:Staphylococcal Infections / Q000382:microbiology / Q000635:transmission / Q000662:veterinary*; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics / Q000502:physiology; D015047:Zoonoses / Q000635:transmission*
keywords: Staphylococcus aureus; bovine intramammary infection; phylogeny; subtyping; zoonotic transfer