炎症性肠病患者中艰难梭菌感染的分子流行特征

Molecular epidemiological analysis of Clostridium difficile infection in patients with inflammatory bowel disease

目的初歩研究上海仁济医院炎症性肠病患者中艰难梭菌的分子流行特征,为炎症性肠病患者中艰难梭菌感染的监控提供证据。方法对2014年6月-2015年6月的222份炎症性肠病腹泻患者粪便标本进行艰难梭菌毒素检测和厌氧培养。采用多位点序列分型(MLST)进行分型,传统PCR方法检测其毒素基因,琼脂稀释法检测艰难梭菌体外药物敏感性,同时对炎症性肠病患者所在病房进行环境中艰难梭菌检测。结果222份粪便标本中艰难梭菌的检出率为13.5%(30/222),克罗恩病和溃疡性结肠炎患者中艰难梭菌检出率为15.7%(22/140)和9.8%(8/82),病房环境共检出4株艰难梭菌。MLST分型22株艰难梭菌为14种ST型,主要型别为ST54型。PCR检测毒素基因显示;TaM+raffl+菌株为主(72.7%,16/22),未检出二元毒素。22株艰难梭菌对氯霉素、四环素、氨苄西林、甲硝唑、万古霉素和美罗培南均敏感,对克林霉素耐药率较高,为63.6%,8株对莫西沙星耐药。结论炎症性肠病腹泻患者中艰难梭菌毒素基因以TcdA+TcdB+型为主,菌株克隆以ST54型为主,该型菌株在病房环境中也有检出。应当密切监测炎症性肠病患者中艰难梭菌的感染毒素基因。

Objective We evaluated the molecular epidemiology of Clostridium difficile strains in patients with inflammatory bowel disease in our hospital so as to provide evidence for effective surveillance of C.difficile infection.Methods From June 2014 to June 2015,a total of 222 stool samples were collected from inpatients with inflammatory bowel disease and sent to clinical microbiological lab to test C.difficile by VIDAS fluorescence enzyme immunoassay and culture.We analyzed the clonal relatedness of bacterial strains by multilocus sequence typing（MLST）,antimicrobial resistance pattern by agar dilution method and prevalence of toxin genes by conventional PCR.Simultaneously,we also examined the environment of the ward where the patients stayed.Results The C.difficile was identified in 30（13.5%） of the 222 patients.The incidence of C.difficile infection（CDI） was 15.7%（22/140） in patients with Crohn＇s disease and 9.8%（8/82） in patients with ulcerative colitis.Four strains of C.difficile were isolated from the ward environment.All the 22 clinical strains from stool samples were typed into 14 STs by MLST analysis.The most common type was ST54（5 strains）.Most（72.7%） of the 22 strains belonged to toxin A＋B＋.However,no isolates contained binary toxin genes.Of the C.difficile strains evaluated,63.6% displayed resistance to clindamycin and eight strains were resistant to moxifloxacin.All the strains were susceptible to the other six drugs,i.e.,chloramphenicol,tetracycline,ampicillin,metronidazole,vancomycin and meropenem.Conclusions Strains with toxin A＋B＋ were the most common C.difficile isolates.ST54 was the most predominant STs in patients with inflammatory bowel disease in our hospital.It＇s necessary to focus on the surveillance of C.difficile lntection in patients witn inflammatory bowel disease.