Saleh. H. Baiu¹, Nadia. E. Al-Abdli^2,

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.

staphylococcus, inducible clindamycin - resistance, D-test