Prevalence and Antibiotic Susceptibility Pattern of Methicillin Resistant Staphylococcus aureus in Tertiary Care Hospitals

Abstract

Aims: Methicillin resistant Staphylococcus aureus (MRSA) is a major nosocomial pathogen in hospitals with hospital based outbreaks world-wide. The present study was carried out to estimate the prevalence of MRSA isolates in clinical specimens and to investigate the sensitivity pattern of resistant isolates against various antibiotics used for treating hospitalized patients. Study Design: The percentage of MRSA was defined as the number of S. aureus isolates resistant to methicillin divided by the total number of S. aureus isolates for which methicillin susceptibility test results were reported. Place and Duration of the Study: The study was conducted during January 2012 to December 2012 at Asian Hospital (tertiary care hospital), Faridabad, Delhi. Methodology: A total of 107 isolates of S. aureus were identified by standard laboratory procedures including catalase test, slide and tube coagulase tests, β- haemolysis on blood agar and growth on mannitol salt agar. Subsequently, antibiotic sensitivity pattern of S. aureus were determined by automated antibiotic susceptibility testing system Vitek 2 compact identification and susceptibility testing (ID/AST) system by using AST-GP-67 card. Result: 23 isolates (21.4%) were identified as MRSA and the remaining 84 (78.6%) were methicillin sensitive S. aureus (MSSA). All MRSA isolates were found to be resistant to penicillin, oxacillin, ciprofloxacin and levofloxacin. The antibiotic resistance pattern of these isolates were high against trimethoprim-sulfamethoxazole (91.3%), erythromycin (47.8%), gentamicin (43.5%), moxifloxacin (42.9%), and less resistance rate was observed against tetracycline (30.4%) rifampicin (13.6%) and clindamycin (4.8%). However, all isolates of Staphylococcus were sensitive to vancomycin, linezolid, nitrofurantoin, quinpristin/daflopristin. Conclusion: Findings presented in this study indicated a high level of resistance to widely used therapeutic agents. An appropriate knowledge on the current antibiotic susceptibility pattern of MRSA is essential for appropriate therapeutic scenario.