PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF METHICILLIN RESISTANT STAPHYLOCOCCUS AUREUS (MRSA) ISOLATES IN A TERTIARY CARE HOSPITAL IN PUNJAB

BACKGROUND: Methicillin resistant Staphylococcus aureus (MRSA) is an important cause of nosocomial infections worldwide. This prospective study was undertaken to know the prevalence of MRSA, to study antimicrobial susceptibility pattern and inducible clindamycin resistance in Staphylococcus aureus isolates obtained from the indoor patients of a tertiary care hospital in Punjab. MATERIALS AND METHODS: All the isolates of Staphylococcus aureus obtained from various clinical specimens were identified by standard methods. MRSA was detected using 30ug cefoxitin disc by disc diffusion method as per CLSI guidelines, 2007. Each isolate was tested for other anti-staphylococcal antibiotics by Kirby-Bauer disc diffusion method. Additionally, inducible clindamycin resistance was studied by disc induction test (D test). RESULTS: During a period of one year, a total of 252 isolates of Staphylococcus aureus were obtained. Eighty six (34.1%) isolates were methicillin resistant Staphylococcus aureus (MRSA) and the remaining 166 (65.8%) isolates were methicillin sensitive Staphylococcus aureus (MSSA). MRSA isolates were significantly less sensitive to common anti-staphylococcal antibiotics as compared to MSSA isolates. However, MRSA isolates showed relatively better sensitivity to some of the antibiotics like netilmicin, levofloxacin, tetracycline and clindamycin. Susceptibility to ciprofloxacin was low in both MSSA (19.8%) and MRSA (9.3%). None of the isolate of Staphylococcus aureus was resistant to vancomycin, linezolid and teicoplanin. Inducible clindamycin resistance was present in 17 (19.7%) MRSA isolates as against 8 (4.8%) MSSA isolates. CONCLUSION: Robust antimicrobial stewardship and strengthened infection control measures are required to prevent spread and reduce emergence of resistance.