Detection of Methicillin Resistance Gene in S. Aureus by PCR

Abstract

Background: Staphylococcus aureus is a serious pathogen responsible for nosocomial and community acquired infections. It is leading cause of healthcare associated infections globally. Methicillin was developed to overcome penicillin resistant S. aureus but by 1961 Methicillin resistant S. aureus (MRSA) were identified in UK. MRSA strains developed due to integration of 21-67 Kbp mobile element called as staphylococcal cassette chromosome mec (SCCmec) into its genome, which harbours the methicillin resistance (mecA) gene. Material and Methods: Known MRSA and MSSA cultures were received from Dr. Y. Patil Medical College, Pune. These organisms were isolated from patient samples like blood, pus, urine, wound swabs and other body fluids. They were characterized and confirmed to be S. aureus based on conventional microbiological methods like Gram staining, coagulase test and growth on mannitol salt agar. The cultures were segregated as MRSA and MSSA. Total 80 PCRs were carried out for detection of mecA gene from MRSA cultures using genomic DNA and 20 from MSSA cultures. Result: All microbiologically identified MRSA gave amplification of 147 bp Amplicon of mecA gene whereas; all MSSA did not show amplification of mecA gene. Conclusion: PCR based tool has advantage over earlier used molecular techniques since Rapid detection of MRSA is critical as it helps in faster patient care and also minimizes the transmission.