Pathogenic characteristics of a fish-derived Enteroaggregative. pathogenicity of fish-derived EAEC

In order to explore the pathogenic characteristics of a fish-derived EAEC (17J105) and discuss the effect of the deletion of its virulence gene pic on its pathogenicity, the changes of intestinal flora in mice challenged to Escherichia coli of different pathogenic types in equal proportion orally were detected, the changes of intestinal flora, colon and cecum tissue expression, tissue bacterial loading as well as the half lethal dose in mice challenged to 17J105 and Δpic were compared. The V3 - V4 region of 16S rDNA of all bacteria in intestinal contents were sequenced by 16S rDNA high-throughput sequencing technology, and the expression level of colon and cecum was analyzed by RNA-Seq analysis. The results showed that, the pathogenicity of 17J105 was supreme in the mixed challenge experiment. The diversity of intestinal flora of 17J105 challenge group was significantly reduced, and the diversity of Δpic challenge group was slightly increased compared with 17J105 challenge group. The deletion of pic gene could reduce the amount of bacteria in tissues and increase the half lethality. A total of 1,161 DEGs were screened out in the Δpic challenge group compared with the 17J105 challenge group. The main difference of KEGG pathway analysis was related to immune and disease pathways. This study provides a reference to the study of public hygiene and prevention of aquatic EAEC and lays a foundation for further study of its public health significance.