Resistance mechanism and drug combination to Pseudomonas aeruginosa in vitro.

OBJECTIVE To understand the resistance mechanism and drug resistance to antimicrobial agents of Pseudomonas aeruginosa(PAE),in order to provide the best drug combination against PAE for clinic with laboratory basis.METHODS All isolates were identified by routine procedure and VITEK-2 automatic bacterial identification instrument and MIC detection used dilution method on agar plate following the instruction of CLSI.RESULTS There were 92 P.aeruginosa(PAE) strains isolated from clinical infectious specimen,which came from respiratory tract specimen mainly(88.04%).Producing metallo-β-lactamases positive rates were 48.91%,AmpC positive rates were 27.17%,and ESBLs PCR positive rate was 29.35%,in which tem-1 positive rate was 15.22% and oxa-10 positive rate was 10.88%,but shv,ctx-m and ges genes were not detected.The ratio of meropenem and imipenem was 18.48%.The super-integrons detecting positive rates were 10.87%.The inhibitory bacterial rate to polymyxin B and meropenem was 95.65% and 80.43%,and to amikacin,piperacillin/tazobactam,imipenem,and other antimicrobial agents was 48.91-71.74%,to Cefoperazone/sulbactam was 36.96%.The synergy of piperacillin/tazobactam and cefoperazone/sulbactam with amikacin was 60.87% and 58.70%,with MIN was 44.57% and 43.48%,and with Polymyxin B was 28.26% and 7.61%,respectively.CONCLUSIONS P.aeruginosa is the most important pathogen in nosocomial infection,its drug resistance becomes more and more higher.Drug resistance of P.aeruginosa is related to multiplex drugresistance mechanisma.It should first select enzyme inhibitor-drugs(piperacillin/tazobactam or cefoperazone/sulbactam) with amikacin or polymyxin B to treat P.aeruginosa clinical infection according to the patient sitration and the results of drug susceptibility test to use antimicrobial agents rationally.