中文摘要：

目的明确深圳地区婴幼儿粪便中分离出的艰难梭菌的毒力及其基因型。方法收集深圳市宝安区妇幼保健院2014-2015年分离出的49株艰难梭菌菌株,PCR检测其毒素A、B的编码基因tcd A、tcd B的携带状况,数字化PCR-核糖体分型方法进行基因分型。结果 49株艰难梭菌tcd A、tcd B携带率分别为44.9%（22/49）和59.2%（29/49）,其中22株tcd A、tcd B均为阳性,7株为tcd A阴性、tcd B阳性;49株菌可分为22种核糖体型,最常见的核糖体型为RT017（7/49,14.3%）,BA03（5/49,10.2%）,BA16（5/49,10.2%）和BA13（4/49,8.2%）。7株RT017菌株均为tcd A-tcd B＋,而最常见的tcd A^＋tcd B^＋菌株（44.9%,22/49）则来自RT017以外的15种核糖体型。结论深圳地区婴幼儿中分离出的艰难梭菌半数以上为产毒株,且产毒株多同时携带tcd A、tcd B基因;基因型则以RT017为主,且均为产毒素B而不产毒素A菌株。

英文摘要：

Objective To investigate the virulence and genotype of Clostridium difficile isolated from infants and children in Shenzhen.Methods Forty-nine isolates of Clostridium difficile were isolated from stool samples of infants and children from 2014 to 2015. The coding genes of toxin A and B were detected by PCR,and the genotype of the Clostridium difficile isolates were tested by digital PCRribotyping method. Results The carrying rates of tcd A and tcd B of Clostridium difficile were 44. 9%（ 22 /49） and 59. 2%（ 29 /49）respectively. Among the 29 isolates carrying tcd B,22 carried both tcd A and tcd B and 7 isolates carried only tcd B. The 49 Clostridium difficile isolates were genotyped as 22 PCR-ribotypes（ RTs）. The most common ribotype was RT017（ 7 /49,14. 3%）,BA03（ 5 /49,10. 2%）,BA16（ 5 /49,10. 2%） and BA13（ 4 /49,8. 2%）. Seven RT017 isolates of Clostridium difficile were all tcd B-positive,but the 22 Clostridium difficile isolates which were both tcd A and tcd B-positive belonged to 15 ribotyes respectively except for RT017. Conclusion Over half of isolates of Clostridium difficile isolated from infants and children in Shenzhen were toxigenic strains in which75. 9%（ 22 /29） carried both tcd A and tcd B genes. The most common ribotype was RT017 which carried tcd B but not tcd A.