Detection of β-lactamases Produced by Imipenem-resistance Acinetobacter Baumannii

Objective To investigate the prevalence of AmpC enzyme,extended-spectrumβ-lactamase(ESBLs)and metallo β-lactamases(MBLs)produced by clinically isolated strain of Imipenem-resistance Acinetobacter baumannii(IRABA)in our hospital and its characterization of drug resistance.Methods The bacteria identification microbial sensitivity tests were conducted by VITEK 2 Auto Microbe System.ESBLs and AmpC enzyme were detected by improved three-dimensional test,in 63 strains of IRABA clinically isolated from January 2008 to September 2009 in our hospital,and MBLs-producing strains were detected by 2-Mercaptopropionic acid synergy test.Results Among the 63 strains of IRABA,45 strains(71.4 %)were AmpC enzyme positive,13 strains(20.6 %)were ESBLs positive,8 strains(12.7 %)were both ESBLs and AmpC enzyme positive.No MBLs producing strains were found.The rates of resistance against 12 antibiotics were significantly higher in AmpC enzymes positive strains than AmpC enzymes negative strains(P0.05).Conclusion The IRABA trains in this study product mainly AmpC enzymes,and the phenomenon of multi-drug resistance is severe.