AUTHOR=Myhill Laura J. , Stolzenbach Sophie , Mejer Helena , Krych Lukasz , Jakobsen Simon R. , Kot Witold , Skovgaard Kerstin , Canibe Nuria , Nejsum Peter , Nielsen Dennis S. , Thamsborg Stig M. , Williams Andrew R. 

TITLE=Parasite-Probiotic Interactions in the Gut: Bacillus sp. and Enterococcus faecium Regulate Type-2 Inflammatory Responses and Modify the Gut Microbiota of Pigs During Helminth Infection

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.793260

DOI=10.3389/fimmu.2021.793260

ISSN=1664-3224

ABSTRACT=<p>Dietary probiotics may enhance gut health by directly competing with pathogenic agents and through immunostimulatory effects. These properties are recognized in the context of bacterial and viral pathogens, but less is known about interactions with eukaryotic pathogens such as parasitic worms (helminths). In this study we investigated whether two probiotic mixtures (comprised of <italic>Bacillus amyloliquefaciens, B. subtilis</italic>, and <italic>Enterococcus faecium</italic> [BBE], or <italic>Lactobacillus rhamnosus</italic> LGG and <italic>Bifidobacterium animalis</italic> subspecies <italic>Lactis</italic> Bb12 [LB]) could modulate helminth infection kinetics as well as the gut microbiome and intestinal immune responses in pigs infected with the nodular worm <italic>Oesophagostomum dentatum</italic>. We observed that neither probiotic mixture influenced helminth infection levels. BBE, and to a lesser extent LB, changed the alpha- and beta-diversity indices of the colon and fecal microbiota, notably including an enrichment of fecal <italic>Bifidobacterium</italic> spp. by BBE. However, these effects were muted by concurrent <italic>O. dentatum</italic> infection. BBE (but not LB) significantly attenuated the <italic>O. dentatum</italic>-induced upregulation of genes involved in type-2 inflammation and restored normal lymphocyte ratios in the ileo-caecal lymph nodes that were altered by infection. Moreover, inflammatory cytokine release from blood mononuclear cells and intestinal lymphocytes was diminished by BBE. Collectively, our data suggest that selected probiotic mixtures can play a role in maintaining immune homeostasis during type 2-biased inflammation. In addition, potentially beneficial changes in the microbiome induced by dietary probiotics may be counteracted by helminths, highlighting the complex inter-relationships that potentially exist between probiotic bacteria and intestinal parasites.</p>