title: Antimicrobial susceptibility and genetic relatedness of bovine Stenotrophomonas maltophilia isolates from a mastitis outbreak.
abstract: OBJECTIVE
  To evaluate the antimicrobial susceptibility and genetic relatedness of 11 Stenotrophomonas maltophilia isolates from an outbreak of bovine clinical mastitis in one herd and two isolates from two separate mastitis cases in two other herds.
  
  
  RESULTS
  Thirteen S. maltophilia isolates were obtained from milk samples from 11 cows from three dairy herds in Japan during 2008. We tested their susceptibility to 14 antimicrobials by broth microdilution and identified their genotypes by enterobacterial repetitive intergenic consensus 2 (ERIC2)-PCR. Every cow had acute mild mastitis (slightly watery foremilk with flakes) without systemic symptoms and all resolved within 3-5 weeks of diagnosis. Eleven of the 13 isolates derived from nine cows in one herd over a 7-month period exhibited a closely related ERIC2 type (A). The remaining two isolates derived from two cows from two other herds exhibited two distinct ERIC2 types (B and C). Most of the 13 isolates exhibited susceptibility to trimethoprim-sulfamethoxazole, chloramphenicol, minocycline and levofloxacin; however, they were resistant to four β-lactams, kanamycin, gentamicin and oxytetracycline. They were intermediate to enrofloxacin.
  
  
  CONCLUSIONS
  Eleven closely related S. maltophilia isolates were involved in a herd outbreak of mastitis to some extent. Bovine S. maltophilia isolates exhibited resistance to many classes of antimicrobials.
  
  
  CONCLUSIONS
  This is a rare report of a herd outbreak of bovine mastitis involving closely related S. maltophilia isolates.
authors.affiliation: Veterinary Clinical Laboratory, Nemuro District Agricultural Mutual Aid Association, Nakashibetsu, Hokkaido, Japan. monishi@kind.ocn.ne.jp
authors.forename: M
authors.initials: M
authors.lastname: Ohnishi
authors.forename: T
authors.initials: T
authors.lastname: Sawada
authors.forename: K
authors.initials: K
authors.lastname: Marumo
authors.forename: K
authors.initials: K
authors.lastname: Harada
authors.forename: K
authors.initials: K
authors.lastname: Hirose
authors.forename: A
authors.initials: A
authors.lastname: Shimizu
authors.forename: M
authors.initials: M
authors.lastname: Hayashimoto
authors.forename: R
authors.initials: R
authors.lastname: Sato
authors.forename: N
authors.initials: N
authors.lastname: Uchida
authors.forename: H
authors.initials: H
authors.lastname: Kato
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015373:Bacterial Typing Techniques; D002417:Cattle / Q000382:microbiology; D004196:Disease Outbreaks / Q000662:veterinary*; D005260:Female; D007564:Japan; D008414:Mastitis, Bovine / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D008892:Milk / Q000382:microbiology; D016133:Polymerase Chain Reaction; D020615:Stenotrophomonas maltophilia / Q000145:classification / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D000900:Anti-Bacterial Agents