Detection of carbapenemase in enterobacteriaceae with modified Hodge test / 中华急诊医学杂志

ABSTRACT

Objective To detect carbapenemase production in enterobacteriaceae by using modified Hedge test (MHT) and investigate the distribution of carbapenemase genes.Methods A total of 3 718 isolates from enterobacteriaceae were collected from 4 hospitals,including Second Affiliated Hospital of Zhejiang University,People's Hospital of Dongyang,Beijing Hospital,and Huaxi Hospital of Sichuan University.Susceptibility of enterobacteriaceae to ertapenem was tested by K-B method.MHT was used to detect carbapenemase in enterobacteriaceae and the common carbapenemase genes were amplified by using PCR.Results The total resistance rate ( resistance and intermediate resistance) of enterobacteriaceae to ertapenem was 3.04％ (113/3718) and there were differences in resistance rate of enterobacteriaceae to ertapenem among 4 hospitals (5.09％,2.15％,2.59％,and 1.72％,respectively).Of the 3718 isolates,2.29％ (85) were positive to MHT,and there were differences in positive rate to MHT among 4 hospitals (4.73％,1.21％,1.06％,and 1.58％,respectivdy).Of 113 non-susceptible isolates to ertapenem,82 were positive to MHT and 31 were negative.Of 85 MHT-positive isolates,82 were resistant or intermediate resistant to ertapenem and only 3 were susceptible.Of 82 MHT-pesitive and non-susceptible isolates to ertapenem,65 were positive to KPC gene,15 were positive to IMP gene (two of them were positive to both KPC and IMP),and 4 were negative to all tested carbapenemase genes.Thirty-one MHT-negative and nonsusceptible to ertapenem and 3 MHT-positive and susceptible isolates to ertapenem were negative to all tested carbapenemase genes.Conclusions MHT is used to detect carbapenemase in enterobacteriaceae with high sensitivity and low false positive rate.KPC gene is the most occurred gene to be dominant in the production of carbapenemase in enterobacteriaceae, and the IMP gene is also responsible to the genesis ofcarbapenemase in enterobacteriaceae..