Prevalence of Panton-Valentine Leukocidin Gene among Community AcquiredStaphylococcus aureus: A Real-Time PCR Study

Abstract

Panton-Valentine leukocidin (luk-pv) is a cytotoxin that causes leukocyte destruction and tissue necrosis. The aim of this study was to determine the prevalence of thepv1,mecA, andnucgenes inStaphylococcus aureusisolates obtained from anterior nares and superficial infection sites of skin in a slum population of West Bengal, India. Expression level ofpv1gene was also analysed. Twenty-twoS. aureusstrains were isolated, and phenotype and genotype specific examinations forS. aureusisolates were carried out. Molecular identification was done by PCR using species-specific 16S rRNA primer pairs and finally 22 isolates were found to be positive asS. aureus. The antibiotic responsiveness of all these isolates and the minimum inhibitory concentration (MIC) of MRSA isolates were determined using the broth dilution method with vancomycin. Antibiogram analysis of isolatedS. aureusstrains with respect to different antimicrobial agents revealed antibiotic resistance ranging from 27 to 91%. The results of MIC for vancomycin showed 95% of strains to be VSSA and 5% to be VISA. 68% isolates were resistant to methicillin. All the isolates were subjected to detection ofpv1, mecA, andnucgenes, and 9%, 68%, and 27% were found to harbourpvl, mecA, andnucgenes, respectively. All the MRSA strains produced high to moderate levels of biofilm.pvlgene expression was carried outin vitroby Real-Time PCR. The low ∆Ct value (0.493) was indicative of high expression ofpvlin oneS. aureusstrain. Thus, detection ofpvlgene in community acquiredS. aureusindicates the emergence of pathogenicS. aureusin community setup in the studied region. The existing exploration is extremely imperative and informative for the high level multi-drug resistantS. aureusinfections inclusive of MRSA.