Analysis of Drug Resistance in Staphylococcus aureus and Detection of mecA and pvl Genes

摘要

This study aimed to investigate resistance in Staphylococcus aureus towards commonly used drugs and further establish a quick screen assay for the detection of pvl and mecA genes using magnetic nanoparticle method. Eighty clinically isolated strains of S. aureus were collected and tested using traditional drug susceptibility test. Furthermore, the bacterial DNA was purified using magnetic nanoparticle method and subsequently the pvl and mecA genes were detected using real-time PCR technique. In some samples, we also investigated the mecA gene expression using real-time PCR. We found that the mecA gene was present in all methicillin-resistant Staphylococcus aureus (MRSA) and in two strains of methicillin-sensitive Staphylococcus aureus (MSSA). Forty strains were identified as MRSA strains, using traditional drug susceptibility test. In MRSA strains, the drug resistance rate of penicillin was up to 100% (data not presented). The drug resistance rates of ciprofloxacin and levofloxacin were 90% and 87.5%, respectively. The drug resistance rate of gentamicin, moxifloxacin and rifampicin were 72.5%, 60%, and 57.5%, respectively. Magnetic nanoparticle method was successfully used as a quick screen assay, enabling the bacterial DNA analysis using real-time PCR. Some strains of MSSA carried mecA gene, changing the strains to MRSA during antibiotic induction. We found that both MRSA and MSSA carried the pvl gene, causing a potentially severe threat to human health.