ABSTRACT
OBJECTIVE To determine the prevalence of antibiotic resistance to macrolide,lincosamide and streptograminB(MLS_B) in Staphylococcus epidermidis caused nosocomial infections and give guide for clinical antibiotics usage. METHODS Totally 126 S.epidermidis isolates were collected to test the minimal inhibitory concentrations(MIC) of erythromycin,clindamycin,clarithromycin,and azithromycin,quinupristin/dalfopristin and cefoxitin.Inducible type of MLS_B resistance(iMLS_B) and MS phenotypes were distinguished by double disk diffusion method(D test) as detailed by the NCCLS. RESULTS Among 126 S.epidermidis isolates,90(71.4%) isolates were meticillin resistant(MRSE),36(28.6%) were meticillin susceptive(MSSE).The rates of antibiotic-resistance to erythromycin,clindamycin,clarithromycin,axithromycin were 92.8%,73.8%,89.7% and 91.3%,respectively.Percentages of strains resistant to erythromycin and clindamycin were 96.7% and 85.6% in MRSE,and 83.3% and 80.6% in MSSE.Constitutive phenotype,inducible phenotype and MS phenotype were detected in 93(73.8%),13(10.3%),and 11(8.7%) isolates,respectively.In constitutive phenotype, the MRSE proportion appeared high(78.5%),in contrast,in inducible phenotype,MSSE proportion appeared high(75%).No resistance to quinupristin/dalfopristin was detected in all isolates(MIC≤1mg/L). CONCLUSIONS The prevalence of antibiotic resistance to MLS_B is high in the collected isolates.The main antibiotic phenotype is constitutive phenotype.MLS_B antibiotics should be used judiciously.
