自建MALDI-TOF MS霉菌数据库的研究

目的建立基质辅助激光解吸电离飞行时间质谱(MALDI-TOF MS)霉菌数据库,提高引起临床相关感染的各种霉菌的鉴定能力。方法收集临床标本来源的霉菌266株,纯培养后进行霉菌18S rDNA扩增测序,获得菌种鉴定结果。选取210株霉菌用于数据库的构建,通过甲酸萃取法提取蛋白,应用MALDI-TOF MS配套的FlexControl软件收集蛋白谱图,采用Biotyper软件构建评价数据库。其余56株霉菌用于数据库鉴定能力的验证,分别用商品化数据库、自建的MALDI-TOF MS数据库和扩展数据库进行菌种鉴定,应用χ2检验比较数据库的鉴定率差异。结果自建本地化MALDI-TOF MS霉菌鉴定数据库包含19个菌属,67个菌种,共计204株霉菌的质谱图。用于数据库验证的56株霉菌中,用商品化数据库鉴定正确18株,鉴定正确率为32.1%,用扩展数据库鉴定正确51株,鉴定正确率为91.1%,差异有统计学意义(P<0.05)。结论自建霉菌数据库提高了霉菌的鉴定能力,从而有助于临床霉菌感染的病原诊断和治疗。

Study of the in-house mold database of MALDI-TOF MS

Objective To set up a mold database of Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry(MALDI-TOF MS),aiming to improve the identification ability of clinical infections with molds.Methods A total of 266 mold strains were isolated from clinical samples.The species identification was performed by amplifying and sequencing the 18S rDNA of fungi after strains with purified culture.Totally 210 strains were assigned for database construction,and the FlexControl software was used to collect the protein spectrum after protein preparing with formic acid extraction method and the Biotyper software was used to construct and assess the database.In order to validate the database,the rest 56 strains were identified by the commercial and the expanding database,respectively.The chi-square test was used to compare the differences between the identification rates of the two databases.Results The in-house mold database included 19 genus,67 species,and 204 strains spectrums in sum.Among the 56 strains for database validation,18 were identified by the commercial database,with the accuracy rate 32.1%,while 51 were identified by in-house database,with the accuracy rate 91.1%,and the difference was statistically significant(P<0.05).Conclusion The in-house mold database can improve the identification ability and then contribute to the pathogen detection and therapy of the clinical mold infections.