“Intestinal colonization with Escherichia fergusonii enhances infectivity of GII.12 human norovirus in gnotobiotic pigs” published in Elsevier

Oct. 13, 2023

Recently Kwonil Jung (Research Scientist), Quihong Wang (Professor), and Linda Saif (Distinguished University Professor) published an article, entitled Intestinal colonization with Escherichia fergusonii enhances infectivity of GII.12 human norovirus in gnotobiotic pigswithin Elsevier Volume 336, 15 October 2023, 199219.

The role of gut microbiota [especially, histo-blood group antigen (HBGA)-expressing bacteria] in influencing human norovirus (HuNoV) infections is unclear. The research team investigated if infectivity of GII.12 HuNoV in gnotobiotic (Gn) pigs is altered by intestinal colonization with Escherichia fergusonii known to express HBGA A and H on their cell surface. Fifteen piglets were randomly grouped: (1) E. fergusonii + HuNoV (n = 6), (2) HuNoV alone (n = 6), and (3) Mock-inoculated (n = 3). Pigs (8-11-day-old) were inoculated orally with GII.12 HuNoV strain HS206 (9.5 log10 genomic equivalents/pig) or mock. For 2 days prior to viral inoculation, pigs were inoculated orally with E. fergusonii [8 log10 colony forming units/pig/day]. Daily fecal consistency, fecal viral RNA or E. fergusonii shedding, and histopathology (at euthanasia) were evaluated. Unlike the reduced infectivity of GII.4 HuNoV observed previously in Gn pigs colonized with Enterobacter cloacae known to express HBGA A, B, and H on the surface, E. fergusonii + HuNoV pigs exhibited significantly higher cumulative fecal HuNoV RNA shedding at PIDs 6–14 and 1–21 compared with HuNoV alone pigs. Mean days of fecal HuNoV RNA shedding were also significantly greater in E. fergusonii + HuNoV pigs (11.8 ± 1.6 days) compared with HuNoV alone pigs (7.0 ± 1.0 days). By immunofluorescent staining, HuNoV antigen-positive bacteria were detected on the surface of the intestinal epithelium, possibly enhancing attachment of HuNoV to enterocytes, suggesting a potential mechanism by which intestinal colonization with E. fergusonii promoted infectivity of GII.12 HuNoV in Gn pigs.