Prevalence and antibiogram of methicillin sensitive and methicillin resistant Staphylococcus aureus isolated from pus samples in a tertiary care teaching hospital

Abstract

Staphylococcus aureus is an important pathogen causing bacterial infection of skin lesions, such as burns, traumatic lesions, diabetic ulcers and post operative infections. The most common organism isolated from wound infections in our hospital is Staphylococcus and there have been several reports of MRSA isolates from pus samples during previous years. The aim of the present work is to study the rate of Staphylococcal wound infection and also to know the Antibiogram of Methicillin Sensitive and Methicillin Resistant Staphylococcus aureus. Staphylococcus aureus isolated from pus samples were identified based on colony morphology, Gram stain, Catalase and Coagulase test. Antibiotic susceptibility testing by disc diffusion was performed by Kirby Bauer method as per CLSI guidelines. Out of 595 samples collected, 534 [89.7 %] yielded growth of one or more bacterial species. Among 534 culture positive samples, 152 yielded pure growth of only staphylococcal species. 40.3% of the wound infections were caused by Staphylococcus species and among them 81.7% were caused by Staphylococcus aureus. The overall rate of MRSA infection in the present study was 29.6%. Significant difference was observed in the susceptibility pattern of Methicillin Sensitive and Methicillin Resistant Staphylococcus aureus. MRSA continues to be a major threat in the health care setting. The increased level resistance pattern of Methicillin Resistant Staphylococcus aureus observed in our study may be due to the fact that ours is a tertiary care hospital with extensive usage of broad spectrum antibiotics leading to survival advantage and persistence of drug resistant pathogens.