Macrolide and lincosamide resistance in staphylococcal clinical isolates in Nablus, Palestine.

BACKGROUND/AIM Macrolide and lincosamide antibiotics are used for the treatment of staphylococcal infections, especially for penicillin-allergic patients. In the present study, we evaluate the prevalence of resistance to macrolide and lincosamide antibiotics among staphylococci isolates. MATERIALS AND METHODS A total of 200 staphylococcal clinical isolates were collected from January 2012 to April 2013. Minimal inhibitory concentrations of erythromycin and clindamycin were determined by agar dilution method. An erythromycin-clindamycin induction test was performed for isolates that were only resistant to erythromycin. Representative erythromycin-resistant isolates were examined for erythromycin resistance genes using PCR. RESULTS Among staphylococci isolates, resistance frequencies of erythromycin and clindamycin were 65.5% and 20.5%, respectively. Erythromycin resistance was found to be mediated by putative efflux (50.4%) and target site modification (49.6%). Inducible target site modification resistance was detected in 19.1% of erythromycin-resistant isolates. Among the examined 36 staphylococci isolates, msr(A), erm(C), erm(A), and mef(A/E) genes were detected in 55.6%, 30.6%, 25%, and 0%, respectively. CONCLUSION Results of the current study indicate the presence of high rates of macrolide resistance and inducible phenotypes among staphylococcal isolates. It is also essential to keep in mind variations of resistance rates among various age groups and specimen types.