The prevalence of resistance to macrolides and lincosamides among community- and hospital-acquired staphylococci and streptococci isolates in southeast Serbia

Abstract

Introduction/Objective The increasing resistance to macrolides and lincosamides among staphylococci and streptococci is becoming a global problem. The aim of this study was to investigate the prevalence of macrolide-lincosamide-streptogramin (MLS) resistance phenotypes in staphylococcal and streptococcal isolates in southeast Serbia.

Methods The MLS phenotypes were determined by the double-disk diffusion method in 2,121 inpatient and outpatient staphylococcal and streptococcal isolates collected during a one-year period at the Center for Microbiology.

Results The methicillin-resistant staphylococci isolates were significantly more resistant to penicillin, erythromycin, clindamycin, gentamicin, and ciprofloxacin (100%, 100%, 29.2%, 65.6%, and 53.1%, respectively) than the methicillin-sensitive ones (93.6%, 64.9%, 12%, 28.9%, and 11.7%, respectively). The inducible clindamycin resistance phenotype was dominant in S. aureus and coagulase-negative staphylococci isolates. S. pneumoniae, S. pyogenes, and S. agalactiae isolates showed very high resistance to erythromycin (77.8%, 46.2%, and 32.4%, respectively). All staphylococci and streptococci isolates were sensitive to vancomycin and linezolid, and all beta-hemolytic streptococci isolates to penicillin and ceftriaxone.

Conclusion The phenotypic triage of staphylococci is necessary in order to separate inducible resistant and truly clindamycin-sensitive isolates. Macrolides should not be recommended for empirical therapy of streptococcal infections. Penicillins remain the drug of choice for treatment of streptococcal infections in our local area.

Keywords: staphylococci; streptococci; MLS resistance phenotypes; inducible clindamycin resistance