Detection of Resistant Gene from MRSA and MRSH Isolates / 中华医院感染学杂志

ABSTRACT

OBJECTIVE To investigate the prevalence of the antimicrobial and disinfectant-resistant genes from the clinical isolates of meticillin-resistant Staphylococcus aureus(MRSA) and meticillin-resistant Staphylococcus haemolyticus(MRSH).METHODS The identification and antimicrobial susceptibility test of MRSA and MRSH isolates were determined by MicroScan auto SCAN4.PCR was used for detecting antimicrobial and disinfectant-resistant genes.The minimal inhibitory concentration(MIC)and minimal bactericidal concentration(MBC)of benzalkonium bromide to staphylococci that carried qacA/B gene were determined by broth dilution method.RESULTS The positive rates of qacA/B,aac(6′)/aph(2″),aph(3′)-Ⅲ,ant(4′,4″),TEM,erm,and tetM from 24 MRSH strains were 37.5%,87.5%,33.3%,29.2%,95.8%,and 94.4%;and 91.7%.respectively,and 30.6%,91.7%,72.2%,8.3%,100%,94.4% and 91.7%,respectively.The MIC of benzalkonium bromide for MRSH and MRSA were both 32-128 mg/L,MBC for MRSH was 256-512 mg/L and for MRSA was 512-1024 mg/L.The MIC and MBC of benzalkonium bromide for standard strain ATCC25923 were 16 mg/L and 32mg/L,respectively.CONCLUSIONS Antimicrobial and disinfectant-resistant genes are commonly prevalent in MRSA and MRSH isolates.