Gene diversities of ESBLs in clinical isolates of Enterobacteriaceae / 中华传染病杂志

ABSTRACT

Objective To study the Genotype of local clinical isolates of Enterobacteriaceae producing extended spectrum ? lactamases. Methods K B test, conjugative transfer test, plasmid profile analysis, PCR, PCR RFLP, and DNA sequencing were used to detect the phenotype and genotype of 33 isolates of Enterobacteriaceae producing ESBLs. Results Eighty five percent of 33 isolates was resistant to cefotaxime which was obviously higher than that to ceftazidime. blaCTX M ESBLs was detected in 28 isolates by PCR, blaTEM DNA in 24 isolates, and blaSHV DNA in 9 isolates. Mutation of E104K was only identified in one TEM ? lactamase produced by EC98A7 by PCR RFLP. No substitution of G238S occurred in 9 SHV ? lactamases. DNA sequencing and DNA alignment showed the blaCTX M DNA fragments from 4 clinical isolates of EC98A7,EB56,CFR78 and, KP9941 belonged to CTX M type 1, with highest identity to blaCTX M 3 or blaCTX M 12 respectively. Conclusions CTX M ESBLs is carried in 85% isolates of Enterobacteriaceae producing ESBLs in this city. Most of the isolates carry 2 or more ? lactamases. E. coli EC98A7 produces two ESBLs, a TEM ESBL and a CTX M ESBL.