The emergence of Mupirocin resistance among the clinical isolates of Staphylococci in a rural tertiary health-care centre of South India

Abstract

INTRODUCTION: Mupirocin is mainly used for decolonisation of Methicillin-resistant Staphylococcus aureus among patients and health-care workers. However resistance originates from coagulase negative staphylococci (CoNS) and spreads to S. aureus by horizontal gene transfer. Hence, the present study was done to determine the overall prevalence of high- and low-level Mupirocin resistance among S. aureus and CoNS and correlate with the occurrence of Methicillin and inducible Clindamycin resistance. MATERIALS AND METHODS: A total of 100 consecutive, non-repetitive, clinical isolates of Staphylococci were obtained from various samples in a rural tertiary care hospital of Karnataka between August and September 2016. Antibiotic susceptibility testing was done according to the Clinical and Laboratory Standards Institute (M100-S25, 2015) guidelines. Low- and high-level Mupirocin resistance was screened using 5 μg and 200 μg discs, respectively. RESULTS: Of 100 staphylococcal isolates, high-level Mupirocin resistance (MupRH) was detected in 13 isolates and low-level Mupirocin resistance (MupRL) was found in 4 isolates. Of 13 HLMR isolates, majority were CoNS (12 out of 13, 92.31%). Even in LLMR isolates, 75% (3 out of 4) were CoNS. All the HLMR and LLMR isolates were Methicillin resistant (P < 0.05). CONCLUSION: High prevalence of Mupirocin resistance was found in the present study. Hence, screening for Mupirocin resistance should be routinely done and the drug must be used judiciously.