Colonization, Virulence Factors, and Antimicrobial Susceptibility Patterns of Staphylococcus Aureus Isolated from the Anterior Nares of Medical and Paramedical Students

Abstract

Background: Hospital environment and healthcare personnel form an integral part of healthcare system. Patients visit the hospital for various reasons. Some patients require hospitalization and others require medical and surgical interventions. Microbes present in the hospital environment and those colonized in the anterior nares, and on the skin of healthcare personnel could pose an increased threat of hospital acquired infections. Staphylococcus aureus (S. aureus) is one among many microbial species with potential to cause mild to severe infections that could be present colonized in the healthcare personnel. This study is aimed to evaluate the colonization of S. aureus in the anterior nares of medical and paramedical students. Methods: Nasal swabs were collected from a total of 100 medical, and paramedical students. The swabs were cultured on blood agar, and the staphylococcal isolates were identified to the species level by using standard and conventional microbiological techniques. The colonies were counted on isolation (<10 colonies-scanty growth; <25 colonies-moderate growth; <50 colonies-moderate to heavy growth; and > 50 colonies; heavy growth). The virulence determinants including hemolysis, pigment production was assessed. The antimicrobial susceptibility testing was performed using Kirby-Bauer disk diffusion method. Results: Microbes had grown in 97% of the nasal swabs. Most frequent bacterial isolates were Coagulase negative Staphylococcus (CONS), and diphtheroid bacteria (bacterial resembling Corynebacterium diphtheriae. S. aureus was isolated in 13% of the study participants. Conclusion: The isolation rates of S. aureus were noted to be 13%. Increased resistance was noted against vancomycin, and commonly used antimicrobial agents. Most isolates demonstrated hemolysis on blood agar.