title: Prevalence of bacterial genotypes and outcome of bovine clinical mastitis due to Streptococcus dysgalactiae and Streptococcus uberis.
abstract: BACKGROUND
  Streptococcus dysgalactiae and Streptococcus uberis are common causes of clinical mastitis (CM) in dairy cows. In the present study genotype variation of S. dysgalactiae and S. uberis was investigated, as well as the influence of bacterial species, or genotype within species, on the outcome of veterinary-treated CM (VTCM). Isolates of S. dysgalactiae (n = 132) and S. uberis (n = 97) were genotyped using pulsed-field gel electrophoresis. Identical banding patterns were called pulsotypes. Outcome measurements used were cow composite SCC, milk yield, additional registered VTCMs and culling rate during a four-month follow-up period.
  
  
  RESULTS
  In total, 71 S. dysgalactiae pulsotypes were identified. Nineteen of the pulsotypes were isolated from more than one herd; the remaining pulsotypes were only found once each in the material. All S. uberis isolates were of different pulsotypes. During the follow-up period, the SCC of S. dysgalactiae-cows was significantly lower than the SCC of S. uberis-cows (P <0.05). Median SCC of S. dysgalactiae-cows was 71 500 cells/ml and of S. uberis-cows 108 000 cells/ml. No other differences in outcome parameters could be identified between species or genotypes.
  
  
  CONCLUSIONS
  Identical S. dysgalactiae genotypes were isolated from more than one herd, suggesting some spread of this pathogen between Swedish dairy herds. The genetic variation among S. uberis isolates was substantial, and we found no evidence of spread of this pathogen between herds. The milk SCC was lower during the follow-up period if S. dysgalactiae rather than S. uberis was isolated from the case, indicating differences in treatment response between bacterial species.
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89, Uppsala, Sweden. asa.lundberg@sva.se.|Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden. asa.lundberg@sva.se.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Lundberg
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89, Uppsala, Sweden. ann.nyman@sva.se.
authors.forename: Ann
authors.initials: A
authors.lastname: Nyman
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89, Uppsala, Sweden. helle.unnerstad@sva.se.
authors.forename: Helle Ericsson
authors.initials: HE
authors.lastname: Unnerstad
authors.affiliation: Department of Animal Health and Antimicrobial Strategies, National Veterinary Institute, SE-751 89, Uppsala, Sweden. karin.persson-waller@sva.se.|Department of Clinical Sciences, Swedish University of Agricultural Sciences, SE-750 07, Uppsala, Sweden. karin.persson-waller@sva.se.
authors.forename: Karin Persson
authors.initials: KP
authors.lastname: Waller
mesh_terms: D000818:Animals; D002417:Cattle; D005260:Female; D005838:Genotype; D008414:Mastitis, Bovine / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D015995:Prevalence; D012621:Seasons; D013045:Species Specificity; D013290:Streptococcal Infections / Q000188:drug therapy / Q000453:epidemiology / Q000382:microbiology / Q000662:veterinary*; D013291:Streptococcus / Q000235:genetics*; D013548:Sweden / Q000453:epidemiology