Journal of Clinical and Diagnostic Research (May 2022)
Detection and Distribution of Low Level and High Level Mupirocin Resistance among Clinical Methicillin Resistant Staphylococcus aureus Isolates
Abstract
Introduction: Prolonged and improper use of antibiotics increases the resistance among pathogens and leads to life-threatening implications and increases mortality. The incidence of mupirocin resistance in Methicillin Resistant Staphylococcus aureus (MRSA) clinical isolates were reportedly increasing. Aim: To determine the rate of high level and low level mupirocin resistance in clinical MRSA isolates in a tertiary care hospital. Materials and Methods: A cross-sectional study was carried out for a period of three months from December 2019 to February 2020 in Department of Microbiology, PSG Institute of Medical Sciences and Research (PSG IMSR), Coimbatore, Tamil Nadu, India. A total of 100 non duplicate Staphylococcus aureus isolates from different specimens were subjected to mupirocin susceptibility by Kirby-Bauer disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) 2019 standards. The low (MuL) and high (MuH) level mupirocin resistance were detected by using 5 and 200 μg mupirocin discs (Himedia) respectively. The isolate exhibiting diameter of ≥14 mm indicates its susceptibility. The isolate exhibiting diameter ≤13 mm for both 5 and 200 μg indicates MuL and MuH strains respectively. Pearson’s Chi-square test was calculated and p-value of <0.05 was considered as statistically significant. Results: Total 51% Staphylococcus aureus isolates were found to be MRSA. In present study, 6 out of 51 (11.8%) MRSA isolates were found to exhibit MuL and 5 out of 51 (9.8%) MRSA isolates were found to be having MuH. Low level and high level mupirocin resistance were not observed in Methicillin Sensitive Staphylococcus aureus (MSSA). Conclusion: The incidence of MuH and MuL resistance among MRSA were found to be 9.8% and 11.8%, respectively. Screening for mupirocin resistant MRSA to be carried out periodically and stringent infection control practices to be in place to prevent further spread of mupirocin resistant MRSA.
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