Study On The MecA Gene,femA Gene And The Multi-resistance In Methicillin-resistant Staphylococcus

Objective To investigate the antibiotic resistance status and the positive rate of the drug resistance gene mecA and femA in methicillin-resistant Staphylococcus in Kunming. To discuss the relationship between the two drug resistance gene and the multi-resistance in methicillin-resistant Staphylococcus.Methods MIC tests were performed to detect the antibiotic resistance status in the clinic methicillin-resistant Staphylococcus isolates. Detect the drug resistance gene in methicillin-resistant Staphylococcus with PCR. The statistical dependence between drug resistance gene and the multi-resistance was analyzed with exact propability.Results The multi-resistant rate of 228 strains MRSA and 73 strains MRCNS was 99．12%,93．15%,respectively. Except the sensitive rate of MRSA and MRCNS to linezolid and vancomycin was 100%,The drug-resistant rate of MRSA and MRCNS to penicillins was 100%. The drug-resistant rate to ciprofloxacin,erythromycin,clindamycin,rifampin,SXT,tetracycline and gentamicin,MRSA was 95．6%,96．9%,95．2%,88．4%,43%,74．3%,66．2%, MRCNS was 79．5%,87．7%,71．3%,31．4%,88．2%,66．2%,53．2%,respectively. The resistant rate to rifampicin, MRSA was higher than MRCNS; but to SXT was opposite. The positive rate of the mecA gene in MRSA and MRCNS by phenotype was 97．81%,97．26%. The positive rate of the femA gene in MRSA and MRCNS was 100%,0,respectively.The multi-resistant rate of the mecA positive strains was higher than the mecA negative strains (P<0．05) . The statistical dependence between mecA gene and the multi-resistance of MRS was high (r of MRSA=0．6282, r of MRCNS=0．6189) .Conclusion The multi-resistant status of MRS in Kunming is severe. The treatment with the antibiotic should be on the basis of the antibiotic susceptibility test. Glycopeptide antibiotics is the first choice to severe generalized infection caused by MRS. The multi-resistant rate of mecA positive strains and mecA negative strains had significant difference. There was statistical dependence between the mecA gene and the multi-resistance of MRS. By detecting both mecA and femA, we can not only perform the interspecies distinguish between Staphylococcus aureus and coagulase-negative Staphylococcus but also judge the type of drug-resistance. So this could provide more prompt and reliable informations for clinical treatments.