RESUMO
Objective To investigate the genotype distribution of CTX-M-type extended-spectrum β-1actamase(ESBLs) by denaturing high-performance liquid chromatography(DHPLC) in Hunan Province and the accuracy of DHPLC assay. Methods The blaCTX-M genes of standard strains and clinical ESBLs-producing Enterobacteriaceae were amplified by multiplex PCR followed by DHPLC and genotype determination. 25 isolates randomly selected were sequenced to assess the accuracy of DHPLC method. Results Among 142 ESBLs-producing isolates, 109 isolates carried blaCTX-M gene (76. 8% ). Four different CTX-M genotypes were detected by DHPLC, including CTX-M-3 (33 isolates), CTX-M-15 (19 isolates), CTX-M-14 (52 isolates) and CTX-M-9 (5 isolates). The DHPLC typing of 25 isolates suggested that 24 isolates were verified uniformly by the sequencing, but one CTX-M-15 isolate typed by DHPLC was shown to be CTX-M-82 by sequencing. Conclusion DHPLC is a powerful tool for genotyping of the resistance gene and is worth being applied in the clinical and scientific research with accurate, rapid and economic advantages.