Reuterin-producing <i>Limosilactobacillus reuteri</i> with glycerol metabolism ameliorates <i>Staphylococcus aureus</i> -induced intestinal inflammation and dysfunction without gut microbiota dependent

<em>Limosilactobacillus reuteri</em> is a vertebrate symbiont that is widely appreciated as being of significant ecological importance for human health. As a unique feature, <em>L</em>. <em>reuteri</em> converts glycerol to the antimicrobial compound reuterin using enzymes encoded in its propanediol-utilization operon and evolves with host-driven diversification. Reuterin-producing <em>L. reuteri</em> HLRE13 was selectively isolated from poultry previously and confirmed to inhibit the growth of <em>Staphylococcus aureus</em> <em>in vitro</em>. However, it remains unclear whether <em>L</em>. <em>reuteri</em> HLRE13 retains these antagonistic properties when ingested in specific-pathogen-free mice. Here, we investigated the ameliorative effects and potential mechanisms of action of <em>L. reuteri</em> HLRE13 in combination with glycerol on <em>S. aureus</em>-induced infection phenotypes in mice. Firstly, our results confirmed that <em>L. reuteri</em> HLRE13 effectively inhibited the intestinal colonization of <em>S. aureus </em>CMCC26003; Secondly,<em> L. reuteri</em> HLRE13 combined with glycerol could alleviate the intestinal tissues damage caused by <em>S. aureus</em> through increasing the expression of ZO-1, Occludin and MUC-2, ameliorate the intestinal systemic inflammatory response, and maintain the balance of gut microbiota by increasing the relative abundance of <em>Lactobacillus</em> and reducing the relative abundance of <em>Staphylococcus</em>. Furthermore, the colonization resistance was also found on<em> L. reuteri</em> HLRE13 combined with glycerol against <em>S. aureus</em> in pseudo germ-free mice, and they exerted the similar effects on alleviating intestinal damage and improving immune function. Combining these results, we speculate that reuterin-producing <em>L. reuteri</em> antagonize <em>S. aureus</em> in mice without the gut microbiota-dependent manner. Overall, our findings will provide a theoretical foundation for the scientific cognition of <em>L. reiteri</em> in maintaining intestinal health by producing reuterin.