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目的初步研究中国艰难梭菌临床分离株的基因分型、毒力和耐药相关基因分子特征。方法采用常规PCR分别检测艰难梭菌A、B毒素的基因tcdA和tcdB、二元毒素(Binary toxin)的cdtA、cdt B基因、和克林霉素耐药相关基因ermB。对其中的产毒艰难梭菌用常规PCR检测16S-23S间隔区多态性,进行基因分型,再用E-test检测对氨比西林(AC)、克林霉素(CM)、甲硝唑(MZ)、万古霉素(VA)的药物敏性。结果12株艰难梭菌中8株为毒素阳性,其中A+B+为5株,A-B+为3株,分别占62.5 %和37.5%;二元毒素均为阴性;耐药基因erm(B)阳性为4株,占50%。8株产毒株中有4个基因型别,以ZRI为主,占62.5%。产毒株对氨比西林、克林霉素、甲硝唑、万古霉素的耐药率分别为37 .5%、87.5 %、12.5 %、0。未发现027型和078型高致病株。结论艰难梭菌产毒株分离率高达66.7 %;中国产毒艰难梭菌临床分离株存在明显的基因多态性,分属于以ZRI为主的4个基因型别;艰难梭菌产毒株对氨比西林、克林霉素、甲硝唑均有一定耐药现象,但对万古霉素敏感。
Objective To study the genotyping, virulence and molecular characteristics of resistance-related genes in clinical isolates of C. difficile in China. Methods The tcdA and tcdB genes of C. difficile A and B toxin, cdtA and cdt B genes of Binary toxin and ermB gene of clindamycin resistance were detected by routine PCR. The genotype of 16S-23S spacer was detected by conventional PCR in C. difficile, and then genotypes were detected by E-test. The antibacterial activity of ampicillin (AC), clindamycin (CM) Azole (MZ), vancomycin (VA) drug sensitivity. Results Eight of the 12 C. difficile isolates were positive for toxins, of which 5 were A + B + and 3 were A-B +, accounting for 62.5% and 37.5%, respectively. Binary toxin was negative. The resistance gene erm (B) 4 positive, accounting for 50%. There were 4 genotypes in 8 strains, mainly ZRI, accounting for 62.5%. The resistance rates of producing strains to ampicillin, clindamycin, metronidazole and vancomycin were 37.5%, 87.5%, 12.5%, 0 respectively. No strains 027 and 078 were found. Conclusion The isolation rate of Clostridium difficile producing strains is as high as 66.7%. The clinical isolates of Clostridium difficile in China have obvious genetic polymorphism, belonging to 4 genotypes mainly including ZRI. Ampicillin, clindamycin, metronidazole have a certain resistance phenomenon, but sensitive to vancomycin.