Analysis In The Relationship Among The Expression Of Meca Gene, The Content Of Pbp2a And The Resistance Of β-lactam Antibiotics

Objective:The present study is to investigate the mechanisms and function of which MecA gene expression, PBP2a protein levels in MRSA toβ-lactam resistance and to study the resistance mechanism of MRSA from the level of molecular biology.Methods:On the level of molecular biology screening using cefoxitin MRSA, MRSA bacteria extracted RNA, reverse transcription into cDNA, Real-Time Real-time fluorescence PCR detection of MecA gene expression level, detection of PBP2a monoclonal latex agglutination titer, agar dilution method Detection of MRSA on cefoxitin, oxacillin and cefazolin, amikacin, levofloxacin, azithromycin, cotrimoxazole, doxycycline, vancomycin, linezolid minimum inhibitory concentration..Results:1.According to the level of resistance of MRSA to cefoxitin,40 MRSA were divided into low resistance group (twelve), the level of resistance group (fifteen), high resistance group (thirteen)2.According to the level of relative internal reference gene, the expression level of MecA gene in MRSA low resistance group, the level of resistance groups, high resistance group were:58.87±30.30,363.37±200.05,1257.72±446.63, potency of the three groups PBPB2a were 1:1,1:21:4,1:4～1:16. 3.PBP2a have quite different levels of expression and levels of resistance to cefoxitin, a difference of 2 to 3 dilution in the same potency level, MRSA of the MecA gene.4.MRSA resistance on cefoxitin, oxacillin, cefazolin was 100.0%, and amikacin, levofloxacin, azithromycin, cotrimoxazole, doxycycline resistance rates were 45.0%,62.5%,65.0%,37.5%,30.0%, MRSA resistance to vancomycin, linezolid were not detected but 40 vancomycin MIC90 MRSA was 2.0μg/ml.Conclusion:1. MecA gene expression levels have a positive correlation with PBP2, the content of PBP2a have a positive correlation with the MRSA level of resistance to cefoxitin in a certain range of concentration.2. Multiple factors have effect PBP2a content and MRSA resistance to cefoxitin levels.3. MRSA with high characteristics of resistance and multiple antibiotic resistance, the susceptibility of MRSA to vancomycin is on the decline.