Prevalence of community acquired MRSA in a tertiary care facility

Traditionally, methicillin resistant Staphylococcus aureus (MRSA) is considered as a nosocomial pathogen, but an increasing prevalence of community acquired MRSA is being reported worldwide including India, which implies a strategic change in the antibiotic of choice for treatment of community acquired Staphylococcal infections, which till now is cloxacillin. This study is aimed at identifying the prevalence and susceptibility characteristics of community acquired MRSA in our hospital. The study group consisted of 208 consecutive MRSA identified on the basis of their resistance to cefoxitin disk (30 microg) by the disc diffusion method and mecA gene detection by polymerase chain reaction (PCR). Isolates were categorized as community acquired MRSA based on criteria for inclusion and their antibiotic susceptibility was compared with that of the hospital acquired MRSA isolates. Among the 208 MRSA analyzed, 18% (n = 37) were community acquired and were from infections such as cellulitis and superficial injuries. The isolates were significantly more sensitive to ciprofloxacin than the hospital acquired MRSA isolates. The prevalence of community acquired MRSA in this study (18%) is comparable to its prevalence in other studies across India. Susceptibility to antibiotics other than glycopeptides was an important characteristic of community acquired MRSA. In the absence of other reliable phenotypic test for its identification, susceptibility to ciprofloxacin is suggested as an alternative. A prudent clinician should be aware that, cloxacillin, the drug of choice for skin infections such as carbuncle and cellulitis, will not be effective in these cases and that community acquired MRSA has a range of antibiotics to choose from, other than the glycopeptides, when compared with that of hospital acquired MRSA.