Prevalence of the Panton-Valentine Leukocidin Gene in Clinical Isolates of Staphylococcus aureus Isolated From Hospitals the Ilam Province of Iran
Background: Panton-Valentine leukocidin (luk-pv) is a cytotoxin that causes leukocyte destruction and tissue necrosis.
Objectives: The aim of this study was to determine the prevalence of the pv1, femA, and mecA genes in staphylococcus aureus isolates from clinical specimens in hospitals in Ilam, Iran.
Materials and Methods: One hundred and sixty Staphylococcus aureus isolates were collected from hospitals in Ilam, Iran, and phenotypic and genotypic examinations for methicillin-resistant S. aureus (MRSA) isolates were carried out. The antibiotic profiles of these isolates, and the minimal inhibitory concentration (MIC) of MRSA isolates was determined using the agar dilution method with vancomycin, cefoxitin, and oxacillin. All isolates were examined using polymerase chain reaction (PCR) primers for the femA, mecA, and Panton Valentine leukocidin (luk-pv) genes.
Results: The results showed 91 isolates (56.88%) were coagulase-positive, and 69 isolates (43.12%) were coagulase-negative Staphylococcus aureus (CNSA). Out of 91 (56.88%) coagulase-positive staphylococci, 32 isolates (35.16%) were resistant to cefoxitin, and 30 isolates (32.96%) were resistant to oxacillin, using disc diffusion method. PCR revealed the presence of the femA gene (510 bp band) in all coagulase-positive isolates (100%), and the mecA gene (513 bp band) was detected in 32 isolates (35.16%); out of 32 MRSA isolates, 13 isolates (40.62%) were positive for presence of the luk-pv gene (433 bp band).
Conclusions: The cefoxitin disk diffusion method showed the best results when compared to oxacillin disk, similar to results from detecting the mecA gene in PCR as a golden test. Studies on MRSA that carry the luk-pv gene should continue to provide significant insight into the prevalence and epidemiology of these important resistant pathogens. Also, the rate of pvl gene-producing isolates showed to be relatively high, and it should be detected in all staphylococcal infections.