The spectrum of antimicrobial resistance among methicillin resistant Staphylococcus aureus (MRSA) in a tertiary care centre in India.

Methicillin-resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen globally, including India. Staph. aureus strains isolated from pus or blood of patients during January 1993 to November 1994 were tested for antimicrobial susceptibility using Kirby-Bauer disc diffusion technique. Among 1382 isolates of Staph. aureus, 332 (24%) were MRSA. Among the latter, 97 per cent were resistant to trimethoprim-sulphamethoxazole; 85.5 per cent to gentamicin and 45 per cent to amikacin. While over 90 per cent were resistant to norfloxacin and ciprofloxacin, only 53 per cent were resistant to ofloxacin. Fifty seven per cent were susceptible to rifampicin and 87 per cent to netilmicin. All tested strains were susceptible to vancomycin. Therefore, when antimicrobials other than vancomycin are considered for therapy, their choice requires the results of in vitro susceptibility testing of every isolate of MRSA.