Phenotypic detection of inducible clindamycin resistance in Staphylococcus aureus : a study from a tertiary care hospital in West Bengal.

Dr Sayantani Endow; Dr Tanushree Mondal

Volume : IX, Issue : II, February - 2020

Phenotypic detection of inducible clindamycin resistance in Staphylococcus aureus : a study from a tertiary care hospital in West Bengal.

Dr Sayantani Endow, Dr Tanushree Mondal

Abstract :

Introduction: The increasing prevalence of methicillin resistance among Staphylococci is an alarming problem. MRSA isolates with inducible clindamycin resistance (iCR) are resistant to erythromycin and sensitive to clindamycin on routine testing. D–test can help to determine whether clindamycin could be used as a therapeutic option. Hence the present study was undertaken to detect incidence of inducible resistance to clindamycin in erythromycin resistant S. aureus isolates by D test and to study the association between clindamycin and methicillin resistance. Materials and Methods: Two hundred and seven isolates of Staphylococcus aureus were tested for methicillin resistance using cefoxitin (30�g) disc by Kirby Bauer disc diffusion method. Inducible resistance to Staphylococci was tested by D test as per CLSI guidelines. Results: Of the total 207 isolates tested, 126 were erythromycin resistant. Among the erythromycin resistant isolates, 37(29.3%) showed clindamycin resistance, 47(37.3%) showed constitutive resistance and the remaining 42(33.3%) were of MS phenotype. Inducible and constitutive resistance was higher in MRSA as compared to MSSA(32.8%,44.2% and 25%,28.5%) respectively. Conclusion: The study emphasizes the fact that every microbiology laboratory should perform D test on routine basis. This will help in detecting inducible clindamycin resistance and thus prevent therapeutic failure.