Incidence of low and high level mupirocin resistance in staphylococcus aureus isolates from clinical specimens
Dinesh Kumar, Kumar Raja Madasu, Sonu Panwar
Aim: Determine the incidence of high-level mupirocin resistance strains, low-level mupirocin resistance strains and mupirocin sensitive phenotypes.Material and method: The present study was a prospective observational study carried out in the Department of Microbiology. MRSA isolates recovered from clinical specimens such as pus, blood, urine, tracheal aspirate, wounds swab, surgical pus and synovial fluid from patients who attended various outpatient departments or admitted to various wards of the Institute during one year period from May 2018 to April 2019 were included in the study.Methicillin resistance among S. aureus was determined using cefoxitin 30 µg discs by Kirby–Bauer disc diffusion method as per Clinical and Laboratory Standards Institute (CLSI) 2016 guidelines. E-test was performed by Kirby Bauer disc-diffusion method as per CLSI guidelines by using Hi Comb mupirocin strip. Isolates with MICs > 512 μg/ml were considered as MuH, those with MICs 8-256 μg/ml were considered as MuL and with <4 μg/ml were considered as mupirocin sensitive.Results: Among 187 Staphylococcus aureus, 43 isolates were MRSA. MRSA isolates were obtained in highest number from pus (69.8%) followed by sputum (9.3%), urine (7%) and blood (4.7%). Out of 43 MRSA isolates, mupirocin resistance were seen in 8 (18.61%) isolates by both E-test and agar dilution method. Conclusion: The study has demonstrated a higher prevalence of both MuH and MuL in MRSA isolates. Thus it is advis able to routinely perform nasal decolonization of healthcare workers to prevent spread of infections among hospitalized patients.