AbstractBackgroundStaphylococcus aureusis a pathogen endemic in India and sometimes deadly for patients in intensive care units.ObjectivesTo determine the antibiotic-resistance pattern, biofilm forming ability, and clonal type ofS. aureusfrom isolates collected in Tamil Nadu (south) and the Mizoram (northeast) regions of India.MethodsWe collectedS. aureusisolates from diagnostic laboratories in Tamil Nadu and Mizoram. An antibiotic susceptibility test was performed according to Clinical Laboratory and Standards Institute methods. Antibiotic-resistant determinants such asmecA,mecC,blaZ,vanA,vanB, andvanCwere confirmed by polymerase chain reaction (PCR). All isolates were further studied for biofilm forming ability. Enterobacterial repetitive intergenic consensus (ERIC)-PCR was used for clonal analysis.ResultsA study of 206 clinical isolates showed 52.9% prevalence of methicillin-resistantS. aureusin Tamil Nadu and 49.4% in Mizoram. Minimum inhibitory concentration tests showed a high prevalence of 67% oxacillin resistance in isolates from Tamil Nadu and 49% in isolates from Mizoram. PCR showed 53%mecAin Tamil Nadu and 49%mecAin Mizoram. Vancomycin-intermediate resistanceS. aureus(VISA) prevalence was lower in isolates from Tamil Nadu (4%) and Mizoram (5%). All methicillin-resistantS. aureus(MRSA) isolates formed biofilms. Clonal analysis revealed a genetic relatedness between the isolates.ConclusionsThe prevalence of MRSA is high in the regions studied, with most of the clinical isolates being multidrug resistant. Adopting appropriate community-based preventive measures and establishing antimicrobial stewardship is highly recommended to minimize the dissemination in antibiotic resistance.