Inducible Clindamycin Resistant Staphylococcus aureus among Patients Attending Tertiary Care Centre: A Descriptive Cross-sectional Study

Abstract

Introduction: Staphylococcus aureus, a superbug, resistant to multiple antibiotics led to growing interest in the usage of macrolide-lincosamide-streptogramin B antibiotics, which are now rapidly developing resistance. This study aims to find the prevalence of inducible clindamycin-resistant Staphylococcus aureus among obtained clinical samples from in-patient and out-patient departments of a tertiary care center.

Methods: This is a descriptive cross-sectional study done in clinical samples from the in-patient and out-patient departments of a tertiary care center from September 2020-May 2021. Ethical clearance was taken from the Institutional Review Committee (Ref: 068/2077/2078). Staphylococcus aureus were isolated and antibiotic susceptibility tests were performed by disc diffusion method. Inducible clindamycin and methicillin resistance Staphylococcus aureus were detected using D-test and cefoxitin disc according to Clinical and Laboratory Standards Institute guidelines. Convenient sampling was done and the data was analyzed using Statistical Package for Social Sciences version 20. Point estimate at 95% confidence interval was calculated along with frequency and proportion for binary data.

Results: Among a total of 141 Staphylococcus aureus isolated, the prevalence of inducible clindamycin resistant phenotype was 41 (29.1%) (21.6-36.59 at 95% Confidence Interval). Whereas, 30 (21.3%) were constitutive clindamycin resistant. The inducible 28 (47.5%) and 19 (32.2%) constitutive clindamycin resistance was higher among methicillin-resistant Staphylococcus aureus.

Conclusions: The frequency of inducible clindamycin resistance among methicillin resistant Staphylococcus aureus was high, which alarms the use of macrolide-lincosamide-streptogramin B antibiotics in Staphylococcus aureus infections. Hence, D-test should be performed to detect inducible clindamycin resistance in routine testing to prevent treatment failure.