外排泵基因在志贺菌分子分类中的应用

Apply Multidrug Resistance Pump Genes for Molecular Taxonomy of Shigella

志贺菌属(Shigellae)是感染性腹泻的重要病原菌之一,志贺菌H24是临床多耐药株。在H24的分类过程中,发现血清分型和16SrRNA分类都有一定的局限性,16SrRNA不能直接把H24鉴定至种,通过分析H24外排泵基因emrE、cmr、ydhE、acrB基因序列信息,尝试利用外排泵的基因序列信息对志贺菌进行鉴定分类。结果表明,H24外排泵基因emrE、cmr、acrB和ydhE具有很强的进化保守性,未发现染色体上的外排泵基因在不同种属之间有明显的水平转移痕迹,对志贺菌仅用16SrRNA基因序列信息连属的分类都不能做到,但结合emrE和cmr的基因序列信息可直接将志贺菌鉴定到种,首次提出以外排泵基因为分子靶标对志贺菌和大肠杆菌进行快速分类的方法。

Shigella is one of the most important pathogens responsible for infectious diarrhea,H24 is a clinical MDR of Shigella spp.In the process of classification of MDR Shigella spp.H24,we found that serotype and 16S rRNA classification have certain limitations,and H24 can not be identified only by sequence analysis of 16S rRNA gene.So we tried to classify Shigella spp.H24 via the sequence analysis of multiple drug-resistance pump genes emrE,cmr,ydhE and acrB.The results showed that genes of emrE,cmr,acrB and ydhE in bacteria are highly evolutionarily conserved and no gene lateral transfer is found among different bacteria.Sequence analysis of 16S rRNA gene can not identify a Shigella spp.at genus level,while sequence analysis of emrE and cmr incombination with the sequence analysis of 16S rRNA gene can identify a Shigella spp.to species.Thus,we firstly proposed that efflux pump gene can be taken as a molecular target for the rapid classification of Shigella and E.coli.