Abstract

Objective: Methicillin-resistant S. aureus (MRSA) strain is one of the main cause of hospital-acquired (HA) and community-acquired (CA) infections. A mobile genetic element - Staphylococcal cassette chromosome mec (SCCmec) carrying mecA gene is responsible for acquiring resistance to methicillin by S. aureus. Further, Panton-Valentine Leucocidin ( pvl) gene, a two component, pore-forming cytotoxin which can cause tissue necrosis, leukocyte destruction, and severe inflammation has been found to be associated with CA rather than HA MRSA strains. Methods: The present study was aimed to assess the antibiogram, presence of mecA, pvl and different SCCmec elements among MRSA isolates and further correlating there relatedness with CA or HA strains. Also to determine the cytotoxic effect of pvl+ MRSA isolates on human PBMCs. Results: Among 24 MRSA isolates, 7 (29%) isolates were found to carry mecA gene. The presence of mecA, pvl and SCC mec type IV were found in 2 (28%), 3 (42%) and 2 (28%) isolates respectively. The effect of pvl+ isolates on human PBMCs indicated that there was less number of viable human PBMCs in pvl positive isolates as compared to pvl negative isolates. Conclusions: The following results led to the conclusion that pvl associated with SCCmec type IV is prevalent in CA and SCCmec type III is prevalent in HA isolates and the pvl gene may have a role in facilitating the immune evasion of S. aureus. However, more studies from different geographical regions of India are needed to clear the picture of the strains prevalent thereby making an effective strategy to counteract against it.