title: A dominant lineage of Mycoplasma bovis is associated with an increased number of severe mastitis cases in cattle.
abstract: Mycoplasma bovis is the most frequent etiologic agent of bovine mycoplasmosis. It causes various diseases in bovines and considerable economic loss due to the lack of effective treatment or preventive measures such as vaccination. In contrast to the US, where M. bovis-mastitis has been reported for a long time, M. bovis infections in Switzerland and Austria were predominantly associated with pneumonia and subclinical mastitis. However, since 2007 the situation has changed with the emergence of severe M. bovis-associated mastitis cases in both countries. In order to evaluate the molecular epidemiology of the bacteria isolated from these infections, recent and old Swiss, along with recent Austrian M. bovis isolates were analyzed by a typing method displaying intermediate resolution of evolutionary relationships among isolates called Multi-Locus Sequence Typing (MLST). The analysis of Swiss and Austrian M. bovis isolates revealed two major lineages. Isolates collected since 2007 in both countries cluster in the lineage I including ST5, ST33, ST34, 36, and ST38-40 (clonal complex 1), while all Swiss isolates recovered before 2007 cluster in the lineage II comprising ST17 and ST35 (clonal complex 5). Further investigations are necessary to understand if lineage I has a higher predilection or virulence toward mammary gland cells than the old lineage or if other factors are involved in the increased number of severe mastitis cases.
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Laenggassstrasse 122, 3012, Bern, Switzerland.
authors.forename: Sibylle
authors.initials: S
authors.lastname: Bürki
authors.affiliation: Institute of Microbiology, Department of Pathobiology, University of Veterinary Medicine, Veterinaerplatz 1, 1210, Vienna, Austria.
authors.forename: Joachim
authors.initials: J
authors.lastname: Spergser
authors.affiliation: Clinic for Ruminants, Vetsuisse Faculty, University of Bern, Bremgartenstrasse 109a, 3012, Bern, Switzerland.
authors.forename: Michèle
authors.initials: M
authors.lastname: Bodmer
authors.affiliation: Institute of Veterinary Bacteriology, Vetsuisse Faculty, University of Bern, Laenggassstrasse 122, 3012, Bern, Switzerland. Electronic address: paola.pilo@vetsuisse.unibe.ch.
authors.forename: Paola
authors.initials: P
authors.lastname: Pilo
mesh_terms: D000818:Animals; D001317:Austria / Q000453:epidemiology; D015373:Bacterial Typing Techniques / Q000662:veterinary; D002417:Cattle; D005260:Female; D014644:Genetic Variation; D005838:Genotype; D008414:Mastitis, Bovine / Q000453:epidemiology / Q000382:microbiology*; D018598:Minisatellite Repeats / Q000235:genetics; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing / Q000662:veterinary; D009175:Mycoplasma Infections / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D045682:Mycoplasma bovis / Q000235:genetics*; D010802:Phylogeny; D013557:Switzerland / Q000453:epidemiology
keywords: Bovine; MLST; Mastitis; Mycoplasma bovis