中国部分地区艰难梭菌PCR 核糖体分型及毒素基因多态性研究

目的了解中国部分地区艰难梭菌聚合酶链反应（PCR） 核糖体型别分布及其A、B毒素基因多态性，为建立适宜中国的艰难梭菌分子检测和分子分型技术提供基础数据，同时在基因水平上为艰难梭菌感染导致的复杂临床表现提供依据。方法对中国3个城市（北京、广州、济南）分离的64株艰难梭菌临床株进行PCR 核糖体分型，并对不同型别的26株代表菌株的A、B毒素基因进行扩增测序。结果64株艰难梭菌中，毒素基因型以A+B+型（45株，70.31%）为主，A-B+型19株（29.69%）。共存在9种PCR 核糖体型别，以017型（21株，32.81%）为主要型别，其次为001型（13株，20.31%）、012型（11株，17.19%）。A-B+菌株中，14株(73.68%)是017型，1株是001型。A、B毒素基因呈现一定的多态性，其中有7种A毒素序列型别（TSTA），6种B毒素序列型别(TSTB)，8种A、B毒素序列型别组合（TSTG）。结论我国部分地区的艰难梭菌可能以PCR 核糖体017型为主，A、B毒素基因在菌株间存在多态性，且核糖体型别与毒素基因多态性间存在相对应的关联。应进一步扩大菌株数量和范围，探寻适合我国的分子检测和分子分型方法，从而帮助医院更好地预防和控制艰难梭菌感染。

PCR ribotyping and toxin gene polymorphism of Clostridium difficile in China

ObjectiveTo understand the distribution of PCR ribotyps and toxin gene polymorphism of Clostridium difficile (C. difficile) in some areas of China, provide the reference sequences for the establishment of appropriate molecular detection and typing methods, and support clinical decision for the complex C.difficile infections.MethodsSixty four C.difficile isolates collected from 3 cities(Beijing,Guangzhou,Jinan) were performed PCR ribotyping analysis. Among them, tcdA and tcdB of 26 representative strains were amplified and sequenced.ResultsAmong 64 C.difficile isolates, 45(70.31%) were type A+B+,19(29.69%) were type A-B+. Nine different PCR ribotypes were obtained. The top 3 ribotypes were 017(21 isolates,32.81%), 001(13 isolates,20.31%), and 012(11 isolates,17.19%). Among A-B+ strains, 14（73.68%）were ribotype 017, 1 was ribotype 001. Toxin gene sequences showed polymorphism, there were 7 TSTA, 6 TSTB, and 8 TSTG.ConclusionThe dominant Chinese ribotype may be 017, and toxin genes show certain polymorphism among strains, there is a corresponding relationship between PCR ribotypes and toxin gene polymorphism. Further study will be performed with expanding strains, so as to find appropriate molecular detection and molecular typing method, and help hospitals to prevent and control C. difficile infection.