Study On The Antibiotic Resistance And Genotype Of Escherichia Coil And Klebsieua Pneumoniae Producing Extended-spectrum Beta-lactamases

Part 1 Study on the antibiotic resistance of Escherichia coil and Klebsieua pneumoniae producing extended-spectrum beta-lactamasesObjective To investigate the prevalence of strains producing ESBLs among Escherichia coil and Klebsieua pneumoniae , look for the best detection substrate of these strains and determine the antibiotic resistance of them . Methods 248 strains of E.coli. and 97 strains of K.pn from January to October ,2002 were investigated for production of extended-spectrum B -lactamases(ESBLs) by phenotypic screening and confirmatory test provided by the National Committee for Clinical Laboratory Standards ;Compared the result of the phenotypic screening and confirmatory test to discuss the best detection substrate of these strains; 16 kind of antibiotics were selected for antimicrobial susceptibility test for the resistance.Results 14.5%(36/248) of E.coli, 25.8%(25/97) of K.pn produced ESBLs; The best detection substrate was cefotaxime, follow cetriaxone, aztreonam and cefpodoxime; All tested strains were susceptible to imipenem, the resistancerate of aminoglycosides,cefoxitin,cefoperazone/ B -lactamase inhibitor combinations was lower than other antibiotics. Conclusions cefotaxime was the best detection substrate of ESBLs; To deal with the ESBLs-producing strains, such antibiotics as imipenem, cefoxitin, B -lactamase inhibitor combinations and others which are sensitive to such strains can be used.