Virulence Genes Encoding for Panton Valentine Leucocidin and Toxic Shock Syndrome Toxin in Methicillin Resistant Staphylococcus aureus

Background: The outcome of Staphylococcal infections ranging from mild skin infection to fatal necrotising pneumonia is determined by the co-presence of virulence factors such as enzymes, toxins (Panton valentine leucocidin & toxic shock syndrome toxin) and methicillin resistance. In this study the association of toxin genes encoding for PVL and TSST was seen with drug resistance. Methods: Staphylococcus aureus isolates collected from clinical samples (pus, tracheal aspirate, wound swabs and blood) from inpatients of the tertiary care hospital. The isolates were analysed for presence of toxin genes and drug resistance. DNA extraction was done by boiling method and target genes were identified by PCR and gel electrophoresis. The data was analysed using Microsoft excel. Chi-square test was used for comparison of qualitative data. Unpaired t test was used for comparison of quantitative data. P value less than 0.05 was taken as significant. Results: Methicillin resistance was seen in 54.8% (108/197) of the staphylococcal isolates. There was no significant difference in MRSA and MSSA distribution amongst hospitalized or outpatients. The PVL and TSST gene was present in 123 (62.4%) and 29 (14.7%) isolates respectively. The presence of both the PVL and TSST were significantly higher in MRSA (P≤0.05). Conclusion: There was significantly higher association of virulence markers such as PVL and TSST in MRSA. The presence of toxins should be investigated from cases of non-resolving MRSA infections to initiate treatment effective against toxins for patient management.