High prevalence of multidrug-resistant MRSA in a tertiary care hospital of northern India

Methicillin-resistant Staphylococcus aureus (MRSA) is an important nosocomial and community pathogen. The objectives of this study were to estimate the prevalence of multidrug-resistant MRSA strains in clinical specimens and to investigate the sensitivity pattern of these strains against various antibiotics used for treating hospitalized and out patients. Strains were identified using standard procedures, and their sensitivity pattern was investigated using such techniques as disc diffusion, minimum inhibitory concentration (MIC), and the mecA gene PCR. Among 783 isolates of S. aureus, 301 (38.44%) were methicillin-resistant, of which 217 (72.1%) were found to be multidrug-resistant. Almost all MRSA strains were resistant to penicillin, 95.68% were resistant to cotrimoxazole, 92.36% were resistant to chloramphenicol, 90.7% were resistant to norfloxacin, 76.1% were resistant to tetracycline, and 75.75% were resistant to ciprofloxacin. Vancomycin was the most effective drug, with only 0.33% of MRSA strains being resistant to it. It is concluded that antibiotics other than vancomycin can be used as anti-MRSA agents after a sensitivity test so as to preclude the emergence of resistance to it and that prevailing problems in chemotherapy will escalate unless indiscriminate and irrational usage of antibiotics is checked.