F-RNA噬菌体YM1肠道宿主分析

【背景】F-RNA噬菌体近年来常被作为水环境中诺如病毒污染的指示物。本课题组前期以大肠杆菌ATCC700891^T为宿主，从人便样中筛选出一株F-RNA噬菌体YM1，其与大肠杆菌噬菌体MS2亲缘关系最近，MS2宿主通常为含有性菌毛的雄性大肠杆菌。【目的】探索F-RNA噬菌体与其肠道宿主及诺如病毒之间的互作关系，筛选YM1的肠道宿主。【方法】采用选择性培养基筛选YM1阳性便样中的大肠杆菌并进行YM1侵染验证，结合16S rRNA基因扩增子测序分析YM1接种前后便样中的差异性菌群种类，对YM1阳性便样中潜在的YM1肠道宿主进行分析。【结果】筛选到351个大肠杆菌菌株，YM1侵染结果表明这些大肠杆菌均不是YM1的宿主；16S rRNA基因扩增子测序分析差异性菌种显示，Enterobacter sp. (OTU144)和Enterobacter sp. (OTU11)这2株肠杆菌属细菌的相对丰度在YM1感染后发生显著性的降低，表明该2种细菌可能为YM1的潜在肠道宿主。【结论】YM1具有严格的宿主特异性，便样中大肠杆菌并非YM1的肠道宿主，同时发现了2种YM1的潜在宿主，为进一步筛选分离YM1的肠道宿主提供了方向和依据。

Intestinal host analysis of F-specific RNA bacteriophage YM1

Background] In recent years, F-specific RNA bacteriophages have been recognized as indicators of human norovirus contamination in aquatic environments. Recently, using Escherichia coli ATCC700891^T as host, our group isolated an F-specific RNA bacteriophage YM1 from human stool sample. This bacteriophage has the closest relationship to E. coli bacteriophage MS2. The hosts of MS2 are usually the male E. coli containing pili. Objective] To explore the interaction of F-specific RNA bacteriophage with its host and norovirus living in the intestine, this study aimed to screen out the intestinal hosts of YM1. Methods] Selective medium was used to screen out the E. coli strains in YM1-positive stool sample, and YM1 infection was verified. In addition, the 16S rRNA gene amplicon sequencing was employed to analyze the differences of bacterial community in stool samples before and after YM1 inoculation, and the potential intestinal hosts of YM1 in the YM1-postive stool sample were analyzed. Results] A total of 351 E. coli strains were isolated from YM1-positive stool sample. However, YM1 infection results showed that none of them were the hosts of YM1 bacteriophage. The 16S rRNA gene amplicon sequencing showed that the relative abundance of Enterobacter sp. (OTU144) and Enterobacter sp. (OTU11) in stool samples were significantly decreased after being infected with YM1, which indicated that these two kinds of bacteria might be the potential hosts of YM1. Conclusion] YM1 targets to certain host in an extremely specific manner. E. coli is not the intestinal host of YM1 in stool sample. At the same time, two potential hosts of YM1 have been identified, which provided directions and references for the isolation and screening of the intestinal hosts of YM1.