Inducible clindamycin resistance in staphylococci isolated from clinical samples.

This study aimed to determine the levels of the macrolides-lincosamides-streptogramins B (MLS(B)) resistance phenotype of Staphylococcus aureus and coagulase-negative staphylococci (CNS) isolates from clinical samples. A total of 521 strains of staphylococci, comprising 230 S. aureus and 291 CNS isolates from various clinical samples, were identified by conventional methods. The double-disc test was applied by placing erythromycin and clindamycin discs on these isolates to investigate the inducible and constitutive MLS(B) resistance phenotypes and MS phenotype. Among the S. aureus strains, 24.3% showed the constitutive and 7.8% the inducible phenotype, while there was no MS phenotype. In the CNS strains, 40.2% showed the constitutive and 14.7% the inducible MLS(B) resistance phenotype, and 18.2% had the MS phenotype. In both S. aureus and CNS strains, the constitutive MLS(B) resistance rate was found to be higher than the rate of inducible resistance. By applying double-disc tests on a routine basis to detect inducible MLS(B) resistance, clindamycin can be effectively used on staphylococcal infections. Additionally, it can be used to survey the MLS(B) resistance of staphylococci strains from specific geographical regions or hospitals.