福氏志贺菌Xv血清型聚合酶链反应鉴定方法的建立及应用

Establishment of PCR assay targeting O-antigen modification genes for serotyping of Shigella flexneri serotype Xv

目的建立福氏志贺菌Xv血清型聚合酶链反应(PCR)鉴定方法。方法根据福氏志贺菌Xv血清型O抗结构,针对O抗合成基因wzx、7;8群抗原决定基因gtr X和MASF IV-1抗原决定基因opt,建立PCR扩增鉴定方法。并应用该方法对139株福氏志贺菌临床分离株进行血清型检测。结果建立一种福氏志贺菌Xv血清型PCR鉴定方法,该体系在一个反应中包括3对引物,Xv血清型PCR扩增全部为阳性,可将Xv血清型与目前已知的其他18种福氏志贺菌血清型完全区分。非福氏志贺菌菌属及腹泻相关菌属菌株检测结果发现无任何PCR扩增产物。对139株不同血清型福氏志贺菌临床分离株的鉴定结果显示,该方法可将Xv血清型鉴定,与血清凝集结果一致。结论本研究建立的福氏志贺菌Xv血清型PCR鉴定方法具有快速、特异的优点,可以用于检测和监测。

Objective To establish a PCR assay for serotyping of Shigella flexneri serotype Xv. Methods Based on O-antigen structure of S. flexneri serotype Xv, three primer pairs targeting O-antigen synthesis gene wzx, antigenicity 7 ;8 determined gene gtrX and MASF IV-1 specific gene opt were designed and used in a PCR assay to establish a molecular assay for serotyping of S. flexneri serotype Xv. A total of 139 clinical isolates of S. flexneri were serotyped with this assay and the results were compared with slide agglutination method. Results A PCR assay targeting O-antigen modification genes of S. flexneri serotype Xv was established. The PCR assay contains three primer pairs, which can identify serotype Xv（ all target genes are positive）in one reaction and can distinguish serotype Xv from other known 18 serotypes of S. flexneri. No amplification products of non ShigeUa and diarrhea related isolates were detected with the assay established. A total of 38 serotype Xv strains were detected from 139 clinical isolates of S. flexneri. The result was consistent with that of slide agglutination method. Condusion This PCR assay is rapid and specific and can be used in Shigella detection and surveillance.