title: The prevalence of genotypes that determine resistance to macrolides, lincosamides, and streptogramins B compared with spiramycin susceptibility among erythromycin-resistant Staphylococcus epidermidis.
abstract: Coagulase-negative staphylococci, particularly Staphylococcus epidermidis, can be regarded as potential reservoirs of resistance genes for pathogenic strains, e.g., Staphylococcus aureus. The aim of this study was to assess the prevalence of different resistance phenotypes to macrolide, lincosamide, and streptogramins B (MLSB) antibiotics among erythromycin-resistant S. epidermidis, together with the evaluation of genes promoting the following different types of MLSB resistance:ermA, ermB, ermC,msrA, mphC, and linA/A'. Susceptibility to spiramycin was also examined. Among 75 erythromycin-resistantS. epidermidis isolates, the most frequent phenotypes were macrolides and streptogramins B (MSB) and constitutive MLSB (cMLSB). Moreover, all strains with the cMLSB phenotype and the majority of inducible MLSB (iMLSB) isolates were resistant to spiramycin, whereas strains with the MSB phenotype were sensitive to this antibiotic. The D-shape zone of inhibition around the clindamycin disc near the spiramycin disc was found for some spiramycin-resistant strains with the iMLSB phenotype, suggesting an induction of resistance to clindamycin by this 16-membered macrolide. The most frequently isolated gene was ermC, irrespective of the MLSB resistance phenotype, whereas the most often noted gene combination wasermC, mphC, linA/A'. The results obtained showed that the genes responsible for different mechanisms of MLSB resistance in S. epidermidis generally coexist, often without the phenotypic expression of each of them.
authors.affiliation: Department of Pharmaceutical Microbiology, Medical University of Lublin, Lublin, Poland.
authors.forename: Marek
authors.initials: M
authors.lastname: Juda
authors.affiliation: Department of Pharmaceutical Microbiology, Medical University of Lublin, Lublin, Poland.
authors.forename: Beata
authors.initials: B
authors.lastname: Chudzik-Rzad
authors.affiliation: Department of Pharmaceutical Microbiology, Medical University of Lublin, Lublin, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Malm
mesh_terms: D002981:Clindamycin / Q000494:pharmacology; D052978:Disk Diffusion Antimicrobial Tests; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics*; D004917:Erythromycin / Q000494:pharmacology; D005820:Genetic Testing / Q000379:methods; D005838:Genotype; D006801:Humans; D008034:Lincomycin / Q000494:pharmacology; D055231:Lincosamides / Q000494:pharmacology*; D018942:Macrolides / Q000494:pharmacology*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D015995:Prevalence; D015572:Spiramycin / Q000494:pharmacology; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000235:genetics* / Q000302:isolation & purification; D025382:Streptogramin Group B / Q000494:pharmacology*
chemical_list: D055231:Lincosamides; D018942:Macrolides; D025382:Streptogramin Group B; D002981:Clindamycin; D004917:Erythromycin; D015572:Spiramycin; D008034:Lincomycin