MALDI-TOF MS自建库对不同来源大肠埃希菌的鉴定能力验证

Identification of Escherichia coli from different sources by MALDI-TOF MS self-built database

目的 收集并建立具有特征的大肠埃希菌MALDI-TOF MS自建库,并观察自建库对不同来源大肠埃希菌菌株的鉴定能力。方法 采集2019年3月-2020年8月新疆医科大学第五附属医院检验科临床标本分离出的142株人源性大肠埃希菌菌株;采集自北京市怀柔区和延庆区养殖场分离出的40株动物源性大肠埃希菌菌株。通过16S rRNA测序确定其种属,并进行MALDI-TOF MS鉴定,筛选出合格的蛋白质指纹图谱,使用MicroID 4.0自建库功能对其进行建库。分别使用本地及北京收集的大肠埃希菌菌株对自建库进行验证,评估自建库对不同来源的大肠埃希菌的鉴别区分能力。结果 基于40株合格的人源性大肠埃希菌菌株的蛋白指纹图谱建立自建库,人源性与动物源性大肠埃希菌菌株对自建库进行验证,鉴定结果分别为96%、83%高度可信,其鉴定结果可信程度差异有统计学意义(P<0.05)。结论 本次建立的自建库可用于区分鉴定人源性与动物源性的大肠埃希菌菌株,自建库的4个代表性特征峰具有地域特征,可用作不同地区菌株的鉴别与参考图谱数据库的补充。

Objective To collect and establish MALDI-TOF MS self-built database with characteristics of Escherichia coli,and to observe the identification ability of E.coli from different sources.Methods 142 strains of E.coli were collected from the hospital from March 2019 to August 2020,which isolated from clinical specimens.Forty strains of animal-derived E.coli were collected from farms in Huairou District and Yanqing District of Beijing.The species genus was determined by 16S rRNA sequencing and MALDI-TOF MS identification to select qualified protein fingerprints.Meanwhile,builting database with using MicroID 4.0 by self-built database function.Self-built database was verified with using E.coli strains from locally and Beijing,respectively.Meanwhile,the ability of self-built database to distinguish E.coli from different sources were evaluated.Results The self-built database was established based on protein fingerprints of 40 human E.coli strains.The self-built library was verified by E.coli strains from human and animal,respectively.The identification results were 96% and 83% respectively.And the differences of credible degree of identification result had significant significance(P<0.05).Conclusion The self-built library established in the study can be used to distinguish E.coli strains from human and animal origin.The four representative characteristic peaks of the self-built database have regional characteristics,which can be used as a supplement to identification and reference map database of strains in different regions.