Staphylococcus aureus carrying lukS/F Panton-Valentine Leukocidin (PVL) toxin genes in hospitals of Lahore city

Panton Valentine-Leukocidin (PVL) toxin is secreted by Staphylococcus aureus and is mostly associated with skin and soft tissue infections (SSTI). This study aims to find out the prevalence of lukS/F-PV gene, which encode PVL toxin from strains of SSTI, burn wounds and nasal colonizers of out-patients and to measure the antimicrobial susceptibility of S. aureus isolates. This is an analytical observational cross-section study and was conducted from July 2014 to June 2015 at four tertiary care hospitals and PCSIR Laboratories Complex, Lahore, Pakistan. A total of 376 random clinical swabs were collected from SSTI (n = 179), nasal nares (n = 134) and burn wounds (n = 63) from out-patients' departments (OPD). The specimens were cultured on nutrient and mannitol salt agar (MSA) and the organism was identified by catalase, coagulase, and DNase tests. Antimicrobial susceptibility, methicillin, inducible clindamycin, and high-level mupirocin (HLMR) resistance were determined as per CLSI guidelines. Molecular identification of mecA and lukS/F-PV genes was performed by PCR. We isolated 127 S. aureus, where 41 (32.3%) were MRSA and 86 (67.7%) were MSSA. All MRSA carried mecA gene whereas lukS/F-PV gene was found in 21 MRSA and 31 MSSA strains. Overall, a high antimicrobial resistance was found against MRSA and lukS/F-PV positive MSSA. Inducible clindamycin and high-level mupirocin resistance (HLMR) was 23.6% and 19.5% respectively. A high rate of PVL toxin gene was detected among S. aureus strains and a high prevalence of antimicrobial resistant strains was observed.