Article Type

Original Study


Objective: The aim of the study was to detect the presence of inducible clindamycin resistance among clinical isolates of Staphylococcus aureus. Background: The resistance to antimicrobial agents among staphylococci is an increasing problem. This has led to renewed interest in the usage of macrolide–lincosamide–streptogramin B (MLSB) antibiotics to treat S. aureus infections. The resistance to macrolide can be mediated by the msrA gene coding for efflux mechanism or by the erm gene encoding for enzymes that confer inducible or constitutive resistance to MLSB antibiotics. Materials and methods: Ninety staphylococcal isolates were collected and were tested for antibiotic susceptibility using the disk diffusion method. Inducible resistance to clindamycin in S. aureus was tested by using the double disk diffusion test as per CLSI guidelines. Results: Inducible MLSBresistance (EryRClinInd) was seen in 7/90 (7.7%) isolates, the constitutive phenotype of MLSBresistance (EryRClinR) was detected in 6/90 (6.6%) isolates, and the MSBphenotype (EryRClinS) was seen in 34 (37.7%) isolates. In these isolates, inducible clindamycin resistance was detected in 4.3% (3/70) of S. aureus and 20% (4/20) of coagulase-negative staphylococci. Conclusion: This study showed that the double disk diffusion test should be used as a mandatory method in routine disk diffusion testing to detect inducible clindamycin resistance in staphylococci for the optimum treatment of patients.