The Drug Resistance And MexAB-OprM Efflux Pump Of Pseudomonas Aeruginosa

ObjectiveTo investigate the the expression of MexAB-OprM and OprD2 and the relationship between the multidrug resistance and MexAB-OprM. Providing the laboratory evidence for guiding antibiotic therapy and controlling nosocomial infections.MethodsBacterial identification and antibiotic susceptibility tests were performed by VITEK 2 Compact system from clinical departments'isolates between July 2008 and June 2009. Multidrug resistence PA were chosen and screened by microdilution test .MexAB-OprM and OprD2 mRNA were detected by real time RT-PCR. The regulation gene mexR of Pseudomonas aeruginosa which overexpression MexAB were amplified by PCR, then the amplified mexR gene were sequenced and identified.Results1. Most Pseudomonas aeruginosa strains were isolated from infants,young children and old people.The strains isolated from ICU stand first.62.2% Pseudomonas aeruginosa were isolated from respiratory tract.2. Pseudomonas aeruginosa were nonsensitive to most antibiotic. piperacillin/tazobactam,Amikacin were always effective to Pseudomonas aeruginosa.3. The ciprofloxacin MIC of 15 strains have declined 8 times with CCCP.After ceftazidime combined with CCCP,MIC of 6 trains have declined 8 times.4. For ciprofloxacin and ceftazidime, RT-PCR show the expression of MexAB-OprM of the sensitive group were lower than nonsensitive group(P<0.05).5. The correlation of RT-PCR and ceftazidime combined to CCCP were almost well(P<0.05).Seven strains without high expression of mRNA were positive with ciprofloxacin combined to CCCP(P>0.05). 6. RT-PCR show the expression of OprD2 of the imipemen sensitive group were lower than nonsensitive group(P<0.05).Conclusions1. Pseudomonas aeruginosa were prevalent in hospital and most of the strains were multi-resistant to antibiotics, we shuould monitor the resistance of bacteria, and use antibiotics reasonably.2. High expression of MexAB-OprM was an important mechanism of multi-resistance.3. The high expression of MexAB-OprM were related to the nonsensitive of ciprofloxacin and ceftazidime but not the mechanism of Pseudomonas aeruginosa resistant to imipemen.4. The lower expression of OprD2 was an important mechanism of Pseudomonas aeruginosa resistant to imipemen.