Prevalence of Panton-Valentine leukocidin gene in Staphylococcus aureus and its molecular epidemiology in 18 teaching hospitals of China

Objective To investigate the distribution of Panton-Valentine leukocidin(PVL) gene in S.aureus,and the clinical implication of PVL gene.Methods PVL gene was detected by PCR in 809 strains of S.aureus isolated from 18 teaching hospitals.Methicillin-resistant S.aureus(MRSA) carrying PVL gene phenotype was determined by K-B method,and were confirmed by mecA-femB double PCR.SCCmec typing was confirmed by multiplex PCR.Pulsed-field gel electrophoresis(PFGE) with SmaI digestion of chromosomal DNA was used for the genotyping analysis.Results We identified PVL gene in 58 isolates.The average prevalence of PVL was 7.2% in S.aureus isolates.The prevalence of PVL gene in MRSA(15/407,3.5%) was lower than in MSSA(43/402,11.1%).The difference was not statistically significant(P0.05).The prevalence of PVL gene was significantly higher in the isolates from outpatients than that from inpatients(P0.05).SCCmec typing was conducted for 15 PVL-positive MRSA isolates.The prevalence of SCCmec II,SCCmec III and nontypable strains accounted for 3.8%,4.7%,and 1.0% respectively(P0.05).PVL-positive MRSA isolates were further typed by PFGE.The most common PFGE type was type A and its related subtypes(73.3%),followed by type B(13.3%),C(6.7%),and D(6.7%).Conclusions PVL toxin can result in serous diseases.It is necessary to identify the genotype timely for adequate control of PVL-positive MRSA outbreak in hospital.