Clonal spread of methicillin-resistant Staphylococcus pseudintermedius in Europe and North America: an international multicentre study

J Antimicrob Chemother. 2010 Jun;65(6):1145-54. doi: 10.1093/jac/dkq078. Epub 2010 Mar 25.


Objectives: The aim of this study was to determine the phenotypic and genotypic resistance profiles of methicillin-resistant Staphylococcus pseudintermedius (MRSP) and to examine the clonal distribution in Europe and North America.

Methods: A total of 103 MRSP isolates from dogs isolated from several countries in Europe, the USA and Canada were characterized. Isolates were identified by PCR-restriction fragment length polymorphism (RFLP), antimicrobial susceptibility was determined by broth dilution or gradient diffusion, and antimicrobial resistance genes were detected using a microarray. Genetic diversity was assessed by multilocus sequence typing (MLST), PFGE and spa typing. Staphylococcal cassette chromosome mec (SCCmec) elements were characterized by multiplex PCR.

Results: Thirteen different sequence types (STs), 18 PFGE types and 8 spa types were detected. The hybrid SCCmec element II-III described in a MRSP isolate was present in 75 (72.8%) isolates. The remaining isolates either had SCCmec type III (n=2), IV (n=6), V (n=14) or VII-241 (n=4) or were non-typeable (n=2). The most common genotypes were ST71(MLST)-J(PFGE)-t02(spa)-II-III(SCCmec) (56.3%) and ST68-C-t06-V (12.6%). In addition to mecA-mediated beta-lactam resistance, isolates showed resistance to trimethoprim [dfr(G)] (90.3%), gentamicin/kanamycin [aac(6')-Ie-aph(2')-Ia] (88.3%), kanamycin [aph(3')-III] (90.3%), streptomycin [ant(6')-Ia] (90.3%), streptothricin (sat4) (90.3%), macrolides and/or lincosamides [erm(B), lnu(A)] (89.3%), fluoroquinolones (87.4%), tetracycline [tet(M) and/or tet(K)] (69.9%), chloramphenicol (cat(pC221)) (57.3%) and rifampicin (1.9%).

Conclusions: Two major clonal MRSP lineages have disseminated in Europe (ST71-J-t02-II-III) and North America (ST68-C-t06-V). Regardless of their geographical or clonal origin, the isolates displayed resistance to the major classes of antibiotics used in veterinary medicine and thus infections caused by MRSP isolates represent a serious therapeutic challenge.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Typing Techniques
  • DNA Fingerprinting
  • Dog Diseases / epidemiology*
  • Dog Diseases / microbiology*
  • Dogs
  • Europe / epidemiology
  • Genes, Bacterial
  • Methicillin-Resistant Staphylococcus aureus / classification*
  • Methicillin-Resistant Staphylococcus aureus / isolation & purification*
  • Microarray Analysis
  • Microbial Sensitivity Tests
  • North America / epidemiology
  • Polymorphism, Genetic*
  • Polymorphism, Restriction Fragment Length
  • Staphylococcal Infections / epidemiology
  • Staphylococcal Infections / microbiology
  • Staphylococcal Infections / veterinary*