Objective To compare the application of three automated microbiology identification and rapid susceptibility assessment systems,Vitek1,Viket2 and BD Phoenix,in detection of extended-spectrum beta-lactamases(ESBLs).Methods The genotypes of 67 clinical isolates of ESBLs-producing E.coli and K.phneumoniae,which were collected from the 1st and 2nd Affiliated Hospital of Zhejiang University,were determined by PCR amplification and sequencing.Meanwhile,these isolates were analyzed by the three automatic microbiology identification system,and the minimum inhibitory concentration(MIC)s for antibiotics were determined.Results Majority of the 67 isolates produced CTXM type of ESBL.Among them,CTX-M-14,CTX-M-22,CTX-M24 and CTX-M-3 were the most frequently detectable types.By using Vitek-AMS,60 isolates(89.6%)were detected to be ESBLs-producing.By using Vitek2,62 isolates(92.5%) were ESBLsproducing.No SHV-12,CTX-M-14 and SHV-28 were detected by the 3 automatic systems.The results of MICs analysis indicated these isolates showed either high resistance for multiple antibiotics or around the boundary areas of MICs test.Conclusions The three automatic analysis systems are able to provide a detectable rate of more than 98% for ESBLs.However,it is needed to further improve the detection for high resistant strain or the strains carrying multiple resistant genes.