Enterobacter cloacae inhibits human norovirus infectivity in gnotobiotic pigs

• Published in: Scientific reports 2016-04, Vol.6 (1), p.25017-25017, Article 25017
• Main Authors: Lei, Shaohua, Samuel, Helen, Twitchell, Erica, Bui, Tammy, Ramesh, Ashwin, Wen, Ke, Weiss, Mariah, Li, Guohua, Yang, Xingdong, Jiang, Xi, Yuan, Lijuan
• Format: Article
• Language: English
• Subjects: 631/326/596/2556; 64; 692/699/255/2514; Animals; B-Lymphocytes - microbiology; B-Lymphocytes - virology; Blood - microbiology; Blood - virology; Caliciviridae Infections - blood; Caliciviridae Infections - microbiology; Cell culture; Colonization; Duodenum; Enterobacter cloacae - physiology; Enterocytes; Gastroenteritis; Gastroenteritis - blood; Gastroenteritis - microbiology; Gastroenteritis - virology; Genome, Viral; Genomes; Germ-Free Life; Gnotobiotic; Humanities and Social Sciences; Humans; Ileum; Infections; Infectivity; Inoculation; Intestine; Intestines - microbiology; Intestines - virology; Jejunum; Lamina propria; Lymphocytes B; multidisciplinary; Norovirus - genetics; Norovirus - pathogenicity; Pathogens; Science; Sus scrofa; Swine; Viral Load; Virus Shedding
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep25017

Human noroviruses (HuNoVs) are the leading cause of epidemic gastroenteritis worldwide. Study of HuNoV biology has been hampered by the lack of an efficient cell culture system. Recently, enteric commensal bacteria Enterobacter cloacae has been recognized as a helper in HuNoV infection of B cells in vitro . To test the influences of E. cloacae on HuNoV infectivity and to determine whether HuNoV infects B cells in vivo , we colonized gnotobiotic pigs with E. cloacae and inoculated pigs with 2.74 × 10 4 genome copies of HuNoV. Compared to control pigs, reduced HuNoV shedding was observed in E. cloacae colonized pigs, characterized by significantly shorter duration of shedding in post-inoculation day 10 subgroup and lower cumulative shedding and peak shedding in individual pigs. Colonization of E. cloacae also reduced HuNoV titers in intestinal tissues and in blood. In both control and E. cloacae colonized pigs, HuNoV infection of enterocytes was confirmed, however infection of B cells was not observed in ileum and the entire lamina propria in sections of duodenum, jejunum and ileum were HuNoV-negative. In summary, E. cloacae inhibited HuNoV infectivity and B cells were not a target cell type for HuNoV in gnotobiotic pigs, with or without E. cloacae colonization.