Genotype distribution of extended-spectrum β-lactamases produced by Escherichia coli and Klebsiella pneumoniae in China

Objective To investigate the genotype distribution of extended-spectrum β-lactamases (ESBLs) produced by Escherichia coli and Klebsiella pneumoniae in ChinaMethods 400 clinical strains of Escherichia coli and Klebsiella pneumoniae confirmed to produce ESBLs were collected from four areas of China Plasmid conjugation, PCR, gene cloning and DNA sequencing were carried outResults 356 of 400 isolates confimed the genotype of ESBLs 328 strains produced only one type of ESBLs, including CTX-M-14 (209 strains), CTX-M-3(57 strains), CTX-M-24(29 strains), CTX-M-22 (8 strains), CTX-M-28 (3strains), CTX-M-9(3 strains), CTX-M-13 (1 strain), CTX-M-27 (1 strain), CTX-M-29 (1 strain); SHV-12(10 strains), SHV-5(4 strains), SHV-2 (2 strains)。Twenty-eight isolates carried two or three types of ESBLs, producing CTX-M-14 and CTX-M-3 together which were the most common typeConclusion CTX-M-type is the most common genotype in ESBLs produced by Escherichia coli and Klebsiella pneumoniae in ChinaCTX-M-14 was the predominant genotype Some isolates produced two or three ESBLs