Inducible Clindamycin Resistance in Methicillin Resistant Staphylococcus aureus

摘要

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 Staphylococcus aureus infections. In vitro routine tests for clindamycin susceptibility may fail to detect inducible clindamycin resistance thus necessitating the need to detect such resistance by a simple D-test on routine basis. The objective of this study was to investigate S. aureus collected isolates for MLSB phenotypes, in particular inducible clindamycin resistance (MLSBi). Methods: Four hundred and forty six S.aureus isolates from samples were evaluated and inducible resistance to clindamycin was detected by D-test as per CLSI guidelines (2012). Results: Among 224 isolates of staphylococci studied, 101 (21.4%) were methicillin-resistant S. aureus (MRSA) and 123 (26.1%) were methicillin-sensitive Staphylococcus aureus (MSSA). Of the 224 staphylococcal isolates 62 (27.7%) were resistant to erythromycin of which 10 (4.46%) showed inducible clindamycin resistance and belonged to the MLSBi phenotype. Among the 10 MLSBi phenotype 7 (6.93%) were MRSA and 3 (2.44%) were MSSA. Conclusion: D-test should be included as a mandatory method in routine disc diffusion testing to detect inducible clindamycin resistance in staphylococci for the optimum treatment of patients.