Molecular epidemiology and genetic linkage of macrolide and aminoglycoside resistance in Staphylococcus intermedius of canine origin

Vet Microbiol. 2001 Mar 20;79(2):155-69. doi: 10.1016/s0378-1135(00)00347-3.


A collection of 77 Staphylococcus intermedius isolates from dogs and cats in Switzerland was examined for resistance to erythromycin. Resistance profiles for 14 additional antibiotics were compared between erythromycin-resistant and susceptible isolates. A resistance prevalence of 27% for erythromycin was observed in the population under study. Complete correlation between resistance to erythromycin, and to spiramycin, streptomycin, and neomycin was observed. The erythromycin-resistant isolates all had a reduced susceptibility to clindamycin when compared to the erythromycin-susceptible isolates. Both constitutive and inducible resistance phenotypes were observed for clindamycin. Ribotyping showed that macrolide-aminoglycoside resistance was randomly distributed among unrelated strains. This suggests that this particular resistance profile is not related to a single bacterial clone but to the horizontal transfer of resistance gene clusters in S. intermedius populations. The erythromycin-resistant isolates were all carrying erm(B), but not erm(A), erm(C), or msr(A). The erm(B) gene was physically linked to Tn5405-like elements known as resistance determinants for streptomycin, streptothricin, neomycin and kanamycin. Analysis of the region flanking erm(B) showed the presence of two different groups of erm(B)-Tn5405-like elements in the S. intermedius population examined and of elements found in Gram-positive species other than staphylococci. This strongly suggests that erm(B) or the whole erm(B)-Tn5405-like elements in S. intermedius originate from other bacterial species, possibly from enterococci.

MeSH terms

  • Aminoglycosides
  • Animals
  • Anti-Bacterial Agents / therapeutic use
  • Cat Diseases / drug therapy
  • Cat Diseases / microbiology
  • Cats
  • Cloning, Molecular
  • DNA-Binding Proteins / genetics
  • Dog Diseases / drug therapy
  • Dog Diseases / microbiology*
  • Dogs
  • Drug Resistance, Microbial / genetics*
  • Genetic Linkage*
  • Macrolides
  • Polymorphism, Restriction Fragment Length
  • Ribotyping / veterinary
  • Staphylococcal Infections / drug therapy
  • Staphylococcal Infections / veterinary*
  • Switzerland
  • Transcription Factors / genetics


  • Aminoglycosides
  • Anti-Bacterial Agents
  • DNA-Binding Proteins
  • Macrolides
  • Transcription Factors