Study of the Ability of Bifidobacteria of Human Origin to Prevent and Treat Rotavirus Infection Using Colonic Cell and Mouse Models

RESEARCH ARTICLE Study of the Ability of Bifidobacteria of Human Origin to Prevent and Treat Rotavirus Infection Using Colonic Cell and Mouse Models Mélanie Gagnon1☯, Allison Vimont1☯, André Darveau2, Ismaïl Fliss1, Julie Jean1* a11111 1 Institute of Nutrition and Functional Foods, Department of Food Science, Laval University, Quebec, Quebec, Canada, 2 Department of Biochemistry, Microbiology and Bioinformatics, Laval University, Quebec, Quebec, Canada ☯ These authors contributed equally to this work. * Abstract OPEN ACCESS Citation: Gagnon M, Vimont A, Darveau A, Fliss I, Jean J (2016) Study of the Ability of Bifidobacteria of Human Origin to Prevent and Treat Rotavirus Infection Using Colonic Cell and Mouse Models. PLoS ONE 11(10): e0164512. doi:10.1371/journal. pone.0164512 Editor: Miren Iturriza-Gómara, University of Liverpool, UNITED KINGDOM Received: April 15, 2016 Accepted: September 25, 2016 Published: October 11, 2016 Copyright: © 2016 Gagnon et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: This work was supported by Fonds de Recherche du Québec - Nature et Technologies, FR068242, to Dr. Ismaïl Fliss, and Fonds de Recherche du Québec - Nature et Technologies, Scholarship B2, to Dr. Mélanie Gagnon. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Rotavirus is the leading cause of severe acute gastroenteritis among children worldwide. Despite effective vaccines, inexpensive alternatives such as probiotics are needed. The aim of this study was to assess the ability of probiotic candidate Bifidobacterium thermophilum RBL67 to inhibit rotavirus infection. Bacterial adhesion to intestinal cells and interference with viral attachment were evaluated in vitro. B. thermophilum RBL67 displayed adhesion indexes of 625 ± 84 and 1958 ± 318 on Caco-2 and HT-29 cells respectively and was comparable or superior to four other bifidobacteria, including B. longum ATCC 15707 and B. pseudolongum ATCC 25526 strains. Incubation of B. thermophilum RBL67 for 30 min before (exclusion) and simultaneously (competition) with human rotavirus strain Wa decreased virus attachment by 2.0 ± 0.1 and 1.5 ± 0.1 log10 (by 99.0% and 96.8% respectively). Displacement of virus already present was negligible. In CD-1 suckling mice fed B. thermophilum RBL67 challenged with simian rotavirus SA-11, pre-infection feeding with RBL 67 was more effective than post-infection feeding, reducing the duration of diarrhea, limiting epithelial lesions, reducing viral replication in the intestine, accelerating recovery, and stimulating the humoral specific IgG and IgM response, without inducing any adverse effect. B. thermophilum RBL67 had little effect on intestinal IgA titer. These results suggest that humoral immunoglobulin might provide protection against the virus and that B. thermophilum RBL67 has potential as a probiotic able to inhibit rotavirus infection and ultimately reduce its spread. Introduction Human rotavirus is the leading cause of severe dehydrating diarrhea in infants and young children worldwide, in both developed and developing countries. Peak incidence occurs in children PLOS ONE | DOI:10.1371/journal.pone.0164512 October 11, 2016 1 / 18 Anti-Rotavirus Activity of B. thermophilum RBL67 Competing Interests: The authors have declared that no competing interests exist. 2 years of age and under, with an estimated 0.3 rotavirus-induced gastroenteritis episode per child-year [1]. Between 1990 and 2011, rotavirus infection caused an estimated 197,000 deaths per year, or 23 per hour [2]. About 90% of these occurred in low-income countries in Africa and Asia and were associated with poor health care [3]. The virus is transmitted primarily via the fecal-oral route and to a lesser extent via vomit, spreading via contaminated food or water, direct person-to-person contact, aerosols, and environmental surfaces [4]. Infectious doses as low as one plaque-forming unit [5], viral loads as high as 1012 particles per gram in feces and vomit [4] and persistence on fomites and hands [6, 7] all contribute to the high incidence of rotavirus illness. Since the spread of the virus is very difficult to control, rotavirus outbreaks occur often in crowded locations such as daycare centers, hospitals and schools [4]. Rotavirus infects primarily mature enterocytes in the intestinal epithelium, leading to malabsorption and osmotic diarrhea [8, 9]. Since no specific anti-rotavirus therapy is currently available, the main treatment is fluid replacement to prevent dehydration and zinc treatment to decrease the severity and duration of the diarrhea [3]. Two effective rotavirus vaccines, namely RotaTeq 1 (Merck and Co) and Rotarix1 (GSK Biologicals), have been available since 2006 and are recommended by the World Health Organization for use in all countries, particularly in those where diarrhea-related mortality in children younger than 5 years is common [3]. The number of countries that have introduced rotavirus vaccines increased from 5 in 2011 to 35 in 2015 [10]. Both vaccines have been reported to be highly effective in high-income settings [11]. Nevertheless, the protection afforded by these live oral vaccines is reduced in low-income settings [12]. Consequently, inexpensive and effective supplementary or complementary therapies remain necessary. The role of intestinal microbiota in modulating enteric viral infections has been highlighted by several recent studies [13, 14], in particular with norovirus [15] and rotavirus [16]. In this context, the use of probiotic strains as an alternative therapy has been proposed [17, 18]. Based on consultation with scientific experts, the World Health Organization in 2001 retained the following (and current) definition of probiotics: “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host” [19]. General benefits associated with probiotics include support of a healthy gut microbiota, a healthy digestive tract and a healthy immune system [20]. More precisely, some probiotic strains have been shown to stimulate gut epithelial cell proliferation significantly, to reduce gut permeability and to enhance immune responses as well as providing other health benefits [21–23]. Decreased duration, severity or incidence of infantile diarrhea has been noted in some pediatric clinical trials in conjunction with rotavirus outbreaks. Several probiotic strains have been tested, including the Gram-positive strains of Bifidobacterium animalis subsp. lactis Bb12 [24], Lactobacillus rhamnosus GG [25, 26], Lb. paracasei [27], B. bifidum, Streptococcus thermophilus [28], (...truncated)