Primary study on the gene typing, molecular characteristics of virulence and resistance associated gene of 12 Clostridium difficile clinical isolates in China / 中国人兽共患病学报

ABSTRACT

To investigate the gene typing, molecular characteristics of virulence and resistance associated gene of Clostridium difficile from clinical isolates in China, the genes tcdA,tcdB of toxin A and B, cdtA,cdt B of binary-toxin, and erm B of clindamycin resistance were detected by conventional PCR. Genotyping of toxic C. difficile were conducted by means of analysis of 16s-23s internal spacer region polymorphism with PCR assay. Then the antibiotic resistance of toxic C. difficile to ampiciline, clindamycin, metronidazole and vancomycin was conducted with E-test. It was found that 8 toxic C. difficile strains were demonstrated out of 12 clinical isolates, in which 5 strains were tcdA+ and tcdB+, and 3 strains tcdA- and tcdB+, accounting for 62.5% and 37.5% respectively. Binary-toxin genes detection were negative in all the strains. Clindamycin resistance associated gene ermB was positive in 4 out of 8 toxic C. difficile strains, accounting for 50%. 8 toxic isolates were typed into 4 gene types, the dominant type was ZR I,accounting for 62.5%. Resistance rate of 8 toxic C. difficile strains against ampiciline(AC), clindamycin(CM), metronidazole(MZ) and vancomycin(VA) was 37.5%,87.5%,12.5%, and 0 respectively. No isolates belonged to ribotype 027 or 078. Isolation rate of toxic C. difficile is high to 66.7%. There is obvious gene polymorphism in clinical isolates of Chinese toxic C.difficite, and ZR I is preponderant genotype in 4 genotypes. C. difficile shows some resistance to ampiciline, clindamycin, metronidazole, but susceptive to vancomycin.