Applied Microbiology

Staphylococcus aureus are primarily found in human moist squamous epithelium of the anterior nares. The incidence of S. aureus has been increasing emergence of drug-resistant strains called Methicillin resistant Staphylococcus aureus (MRSA). Medical students, second year onwards, are posted in various OPDs, wards, ICUs and operation theatres. Students with S. aureus nasal carriage may disseminate S. aureus to patients. This study was conducted to investigate the carrier rate of S. aureus among hospital unexposed & exposed medical students, comparing biofilm forming ability and its correlation with antibiotic resistance. 181 healthy medical students of Veer Chandra Singh Garhwali Government Medical Sciences & Research Institute, Uttarakhand, unexposed (n=74) and exposed (n=107) to the hospital environment volunteered in this study. Nasal swabs were obtained & cultured for the detection of S. aureus. Kirby-Bauers disc diffusion test for antibiotic susceptibility was performed. Beta lactamase production was identified by using Sykes and Mathew’s test tube and agar plate methods. Congo Red Agar (CRA) and 0.1% Crystal Violet Assay (CVA) was done to see ability to form in vitro biofilm by isolated S. aureus. 29.28% medical students were found to be healthy carrier of S.aureus, for unexposed 17.57% and exposed 37.38%. MRSA carriage was observed in one student (exposed group). Prevalence of S.

aureus nasal carriage increases with the duration of exposure to the hospital environment. The nasal carriage of S. aureus in medical students indicates the potential danger of dissemination of S. aureus including MRSA from them to the hospitalized patients. Biofilm producing strains indicates the potential possibility of acquiring implant associated infection.