Analysis on species classification and chracteristics of drug resistance and virulence in CTX-M-producing Escherichia coli isolated from urine culture / 国际检验医学杂志

ABSTRACT

Objective To analyze the species classification and chracteristics of drug resistance and virulence in CTX-M producing Escherichia coli isolated from urine culture.Methods Escherichia coli cultured by urine were collected from our hospital during 2014,the ring disk diffusion test was implemented to determine the bacterial susceptibility,the EBLs determination test was used to analyze the bacterial EBLs producing situation;the enterobactoer duplicated gene spacer consensus sequency PCR(ERIC-PCR) was adopted to perform the genetic relation analysis;PCR was used to amplify the CTX-M encoding genes and multiple virulence genes iutA,ompT,fyuA,fdeC,fimH,traT,cvaC,pap,kpsMT,pAI,usp,aer,hlyA,cnf and chuA;the multiple PCR was used to analyze the species calssification of CTX-M-producing Escherichia coli;these strains of bacteria were classified as the CTX-M-producing group and non-CTX-M-producing group according to the results of CTX-M coding gene detection,the differences in the antibacterial drug resistance and virulence genes between the two gorups were performed the contrastive analysis.Results One hundred and sixty-two strains of E.coli by urine culture had no genetic correlation,among 126 EBLs positive strains,91 strains produced CT-M,in which 57 strains of CT-M producing Escherichia coli belonged to type D,and 116 strains belong to Type B2.The statistical analysis found that the drug resistance rate in the CTX-M-producing group was significantly higher than that in the non-CT-M producing group (except for imipenem),the prevalence of virulence genes including iutA,chuA and traT in the CT-M producing bacteria group was significantly higher than that in the non-CTX-M-producing group(P=0.001,0.006,0.000)Conclusion CTX-M-producing E.coli is main pathogenic bacterium of urinary infection in our hospital,its majority belong to type D with increased drug resistance,moreover has close correlation with virulence genes iutA,chuA and traA and is a pertential threat in clinical treatment of urinary infection.