一种新型艰难梭菌产毒株检测试剂临床应用研究

A study on clinical application of a novel reagent detecting toxigenic strains of Clostridium difficile

目的通过与GeneXpert工作站检测及质谱鉴定结合的参考方法检测临床粪便标本中艰难梭菌产毒株结果的比对,评价一种液体形式即用型显色培养基检测艰难梭菌产毒株的性能。方法此研究为临床应用研究。收集2017年3至11月河南省人民医院收治的322例腹泻患者粪便标本,分别用显色培养基、GeneXpert工作站及CCFA选择性培养并质谱鉴定,以GeneXpert工作站结合质谱鉴定为参考方法,采用SPSS 13.0软件进行kappa分析,并用标准菌株考察显色培养基的检测限及抗干扰能力。结果显色培养基检测敏感度92.86%(52/60),特异度96.99%(258/266),阳性预测值86.67%(52/60),阴性预测值98.47%(258/262),kappa分析两者的一致性较好(kappa=0.874,P<0.01),显色培养基对产毒株ATCC9689的检测限为菌液浓度10^3CFU/ml,而非产毒株ATCC43593和产气荚膜梭菌ATCC13124即使0.5麦氏单位也不产生干扰。结论即用型显色培养基直接检测艰难梭菌产毒株性能与参考方法相似,且操作简单、无需厌氧培养条件,值得扩大临床研究,为基层医疗机构推广做准备。

Objective To evaluate the performances of a "ready-to-use"liquid chromogenic medium for detecting toxigenic strains of C.difficile from stool specimens,by comparing with the reference method of combined GeneXpert detection with MALDI-TOF MS identification.Methods This study was a clinical application research.A total of 322 stool specimens from patients with diarrhea in Henan Provincial People's Hospital were detected by using this liquid chromogenic mediumor by combination of GeneXpert and MALDI-TOF MS identification after CCFA culture from March to November 2017.The reference method was combined GeneXpert detection with MALDI-TOF MS identification.Data were analyzed with kappa analysis by use of SPSS 13.0.In this study,the limit of detection and anti-interference capability of chromogenic medium were determined with standard strains.Results This assay had a sensitivity of 92.86%(52/56), a specificity of 96.99%(258/266),a positive predictive value of 86.67%(52/60),and a negative predictive value of 98.47%(258/262).Furthermore,this assay was well consistent with the reference method (kappa =0.874,P <0.01).The limit of detection of this assay was 103CFO/ml for toxigenic strain of ATCC9689,and there was no interference by non-toxigenic strain of ATCC43593 or Clostridium perfringens (ATCC13124)even.When the concentration of ATCC9689 was as low as 0.5 McFarland. Conclusions It is worth expanding clinical research for this "ready-to-use"chromogenic medium and preparing for its popularization in primary medical institutions,due to its similar performance to the reference method for detecting toxigenic strains of C.difficile,simple operation and no need of anaerobic condition.