SENSITIVITY PATTERN OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS ISOLATED FROM SURGICAL SITE INFECTIONS

Abstract

Surgical site infections are an important cause of health care associated infections among surgical patients. Patients who develop surgical site infections have longer hospital stays, more expensive hospitalizations, and increased mortality. They are the second most commonly reported nosocomial infection and they count for approximately a quarter of all nosocomial infections. This was a retrospective study conducted at a tertiary care hospital in South India, from June 2010 to December 2011. Testing for Methicillin resistance was performed by modified Kirby Bauer Disc Diffusion method using Cefoxitin (30μg) as recommended by the Clinical and Laboratory Standard Institute. A total of 195 aerobic bacteria were isolated.  114 were Gram positive cocci (58.4%) and 81 were Gram negative bacilli (41.5%). The most common organism was S. aureus, with 69 isolates (31.2%). Out of 61 isolates of S. aureus, 12 (19.6%) were Methicillin resistant. Highest resistance was seen with Penicillin and least resistance to Vancomycin and Linezolid. Resistance to Ciprofloxacin was and Gentamicin was 75% and 58.3% respectively. But the alarming sign is the resistance to Cephalosporins group of antibiotics which was more than 50%. We did not find any resistance to Vancomycin and Linezolid. Several studies all over the world have well established that the early detection of Methicillin resistance is very essential in the prognosis of infections which are caused by S. aureus as many of these infections are life threatening. The regular surveillance of SSIs and monitoring of antibiogram of MRSA will help in formulating a definite antimicrobial policy and reduce the use of powerful antibiotics like Vancomycin and Linezolid and preserve them for the treatment of life threatening infections.

Key words: Surgical site infection, MRSA, antimicrobial susceptibility, nosocomial infections