title: Phenotypes of staphylococcal resistance to macrolides, lincosamides and streptogramin B (MLS) in a Turkish university hospital.
abstract: Resistance to macrolides, lincosamides and streptogramin B (MLS) which is expressed either constitutively or inducibly, is mediated by erm genes (erm A, erm B, and erm C in staphylococci). The transposon TN 554, harbouring the erm A gene also encodes spectinomycin resistance. In Turkey, data related to MLS resistance phenotypes of staphylococci are not available. In this study, we screened 500 consecutive clinical isolates of staphylococci isolated in Hacettepe University Hospital, for MLS and spectinomycin resistance by the standard disk diffusion method. All MLS-resistant isolates were further tested for spectinomycin susceptibility by the agar screening method. Of 500 staphylococcal isolates, 368 (73.6%) were susceptible and 132 (26.4%) were resistant to MLS antibiotics. Ninety-one (18.2%) of the resistant isolates exhibited a constitutive resistance pattern, whereas 40 were inducibly resistant. MS (resistance to macrolides and lincosamides only) resistance was detected in only one isolate (0.2%). Of 40 inducibly resistant isolates, 21 were found to be resistant to spectinomycin by both the disk diffusion and agar screening tests, probably indicating a presence of the erm A gene. These results suggest that MLS resistance has been considerably high among clinical isolates of staphylococci in our hospital. On the whole, constitutive resistance was the pattern most frequently encountered. In contrast, MS resistance was very rare. Further epidemiological and molecular investigations are required for clarification of the data presented.
authors.affiliation: Hacettepe University, Faculty of Medicine, Department of Microbiology and Clinical Microbiology, Ankara, Turkey.
authors.forename: F
authors.initials: F
authors.lastname: Tunçkanat
authors.forename: S
authors.initials: S
authors.lastname: Arikan
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D006785:Hospitals, University; D006801:Humans; D055231:Lincosamides; D018942:Macrolides; D008826:Microbial Sensitivity Tests / Q000379:methods; D010641:Phenotype; D013203:Staphylococcal Infections / Q000382:microbiology; D013210:Staphylococcus / Q000145:classification / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D014421:Turkey; D014769:Virginiamycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D055231:Lincosamides; D018942:Macrolides; D014769:Virginiamycin