MALDI-TOF-MS鉴定宋内志贺菌的临床应用

摘要

objective To construct a database of Shigella sonnei isolates identified by matrix-assisted laser desorption/ioniza-tion-time of flight (MALDI-TOF-MS) in order to achieve rapid identification of clinically isolated Shigella sonnei. Methods A mass spectrometry database of Shigella sonnei isolates identified following extraction method was constructed. A total of 200 wild-type Shigella sonnei strains were identified following direct-smear method and extraction method, respectively. Meanwhile, the iden-tification by MALDI-TOF-MS was conducted for different phases of Shigella sonnei strains, at different laser intensity of the instru-ment and at different sample storage time. Then, 100 Escherichia Coli strains were identified to verify the specificity of the newly-constructed database. Results Concordance rates were 100% for the identification following extraction method, and 71.5% for the identification following direct-smear method. The results of the identification for different phases of Shigella sonnei strains and at dif-ferent laser intensity of the instrument were not significantly different (P>0.05) , and the results of the identification at different sam-ple storage time were significantly different (P<0.05). Identification concordance rate of Escherichia Coli were 96.0% based on the newly-constructed database. Conclusions Based on the database of Shigella sonnei isolates identified by MALDI-TOF-MS follow-ing extraction method, a rapid and correct identification of Shigella sonnei to the species level is obtained, and a rapid diagnosis of the clinical strains of the diarrheal pathogenic bacteria is realized.%目的：建立基质辅助激光解吸电离飞行时间质谱（matrix-assisted laser desorption/ionization-time of flight mass spectrometry, MALDI-TOF-MS）鉴定宋内志贺菌的质谱数据库，实现对临床分离宋内志贺菌的快速鉴定。方法建立经提取法处理后鉴定宋内志贺菌的质谱数据库。在分别使用直接涂抹法和提取法处理后对200株宋内志贺菌野生株进行鉴定验证；同时针对宋内志贺菌的不同菌相、不同激光强度和不同样本保存时间分别进行MALDI-TOF-MS鉴定。再选取100株大肠埃希菌，进行MALDI-TOF-MS鉴定，以确定新建数据库的特异性。结果宋内志贺菌经提取法处理后的鉴定符合率为100%，经直接涂抹法处理后的鉴定符合率为71.5%。宋内志贺菌不同菌相和不同激光强度的鉴定结果差异无统计学意义（P＞0.05）；而样本不同保存时间鉴定结果差异有统计学意义（P<0.05）。使用新数据库后，大肠埃希菌鉴定符合率为96.0%。结论经提取法处理后应用MALDI-TOF-MS鉴定宋内志贺菌建立的质谱数据库，能快速、准确鉴定宋内志贺菌到种水平，满足腹泻病原菌临床分离株的快速诊断。