Molecular epidemiology and genetic linkage of macrolide and aminoglycoside resistance in Staphylococcus intermedius of canine origin.
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.
Institute for Veterinary Bacteriology, University of Bern, Länggass-Strasse 122, CH-3012, Bern, Switzerland. patrick.boerlin@vbi.unibe.ch
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Boerlin
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Burnens
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Frey
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Kuhnert
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J
Nicolet
D000617:Aminoglycosides; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D002371:Cat Diseases / Q000188:drug therapy / Q000382:microbiology; D002415:Cats; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics; D004283:Dog Diseases / Q000188:drug therapy / Q000382:microbiology*; D004285:Dogs; D004352:Drug Resistance, Microbial / Q000235:genetics*; D008040:Genetic Linkage; D018942:Macrolides; D012150:Polymorphism, Restriction Fragment Length; D021521:Ribotyping / Q000662:veterinary; D013203:Staphylococcal Infections / Q000188:drug therapy / Q000662:veterinary*; D013557:Switzerland; D014157:Transcription Factors / Q000235:genetics
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D004268:DNA-Binding Proteins; D018942:Macrolides; D014157:Transcription Factors