ABSTRACT
Objective To understand the nosocomial infection distribution,drug resistance characteristics and carbapenemases-producing phenotype of Pseudomonas aeruginosa (PAE)and Acinetobacter baumannii (ABA).Methods The nosocomial infection strains of non-repeated PAE and ABA isolated in this hospital and the infected cases from July 2012 to July 2013 were retrospec-tively collected.The antimicrobial susceptibility test was conducted by the disk diffusion method(K-B method).The modified Hodge test was adopted to preliminarily screen carbapenemase and the positive strains of preliminary screening were further detected met-allo-beta-lactamase(MBL)by 2-mercaptopropionic acid synergy test.Results During the study period,250 strains of non-repeated PAE and 132 strains of ABA were included.All of them were primarily isolated from sputum specimens,accounting for 55.5%.The department distribution was dominated by the intensive care units(ICU),accounting for 20.9%.The antimicrobial susceptibility test showed that the sensitivity of PAE to the testing anti-microbial drugs was more than 70%,its resistance rates to IPM and MEM were 8.5% and 9.5% respectively.However,the resistance rates of ABA to the testing anti-microbial drugs were up to 35.2%-77.4%,its resistance rates to IPM and MEM were 35.2%,39.1% respectively.The occurrence rates of multidrug-resist-ant and pandrug-resistant ABA nosocomial infection was higher than that of PAE,which were 44.7% and 24.0% and 9.1% and 2.8%,respectively.Among 40 strains of carbapenem-resistant PAE,11 strains(27.5%)were positive in the preliminary screening and 2 strains(18.2%)were positive of MBL phenotype.Among 49 strains of carbapeneme-resistant ABA,37 strains(75.5%)were positive in the preliminary screening and only 1 strain(2.7%)was positive of MBL phenotype.Conclusion PAE and ABA in our hospital exhibit different resistance to common antibacterial drugs.The monitoring should be strengthened.The production of car-bapenemsa is one the main mechanisms for PAE resistance to carbapenems.The detection rate of MBL-producing PAE and ABA is lower in our hospital.
