[Identification of active efflux system gene qacA/B in methicillin-resistant Staphylococcus aureus and its significance].

OBJECTIVE:To detect the active efflux gene qac gene in methicillin-resistant Staphylococcus aureus (MRSA) by hem-nested polymerase chain reaction (PCR) and to learn the carrier condition of qac gene. METHODS:The active efflux gene qacA/B and qacB of 80 strains MRSA isolated from clinical specimens from Aug 2006 to March 2008 were amplified in vitro by hem-nested PCR with the primers designed by computers based on qac information of Genbank, and the PCR fragments were sequenced and analyzed. RESULTS:We detected qacA/B in 19 out of the 80 MRSA strains (23.75%) and qacB in 18 out of the 80 MRSA strains (22.5%). Compared with sequences of qacA (NO.X56628) and qacB(NO.AF535087) in the Genbank, 98% and 97% were identical, respectively. CONCLUSION:The active efflux gene qac gene in MRSA is detected by hem-nested PCR. The proportion of qac gene positive strains is high in clinical practice, which is related to its multi-antibiotic resistance.