OBJECTIVE To investigate the production of AmpC enzyme and ESBLs in Gram-negative bacilli and their drug-resistance to provide basis for reasonable use of antibiotics in clinical practice.METHODS All bacteria were identified by VITEK-32 system and disk test.RESULTS The main five strains of all 184 Gram-negative bacilli were Pseudomonas aeruginosa(24.4%),Acinetobacter baumannii(19.3%),Enterobacter cloacae(14.8%),Escherichia coli(10.2%) and Klebsiella pneumoniae(9.7%).The AmpC enzyme-producing rate was 53.8% and 14.7% in E.cloacae and A.baumannii the ESBLs-producing rate was 35.3%(12/34) and 15.4%(4/26) in A.baumannii and E.cloacae.P.aeruginosa was sensitive to imipenem and the drug-resistance rate of K.pneumoniae was 0%.CONCLUSIONS ESBLs and AmpC enzymes are important mechanisms of the drug-resistance of Gram-negative bacilli.

OBJECTIVE To explore the clinical distribution and drug resistance of extended-spectrum ?-lactamases(ESBLs) producing Enterobacter cloacae.METHODS The clinical distribution and drug resistance of 73 strains of E.cloacae and ESBLs producing E.cloacae identified in our hospital from Jan 2002 to Jan 2004 were analyzed.RESULTS Among them,the highest detectable rate was in respiratory department and from phlegm specimen.No ESBLs producing E.cloacae and non-(ESBLs) were resistant to imipenem;no non-ESBLs were resistant to cefepime,but some ESBLs producing E.cloacae was resistant to it;all ESBLs producing E.cloacae and non-(ESBLs) were resistant to ceftriaxone and amoxicillin/clavulanic acid.CONCLUSIONS E.cloacae is one of the(commonest) pathogens in nosocomial infection,and ESBLs producing E.cloacae has a high detectable rate,its drug resistance has increased;the clinic should choose antimicrobial agents rationally according to drug sensitive tests in vitro.