L-Arabinose inhibits Shiga toxin type 2-converting bacteriophage induction in Escherichia coli O157:H7

Abstract

The pathogenicity of Escherichia coli (E. coli) O157:H7 is predominantly associated with Shiga toxin 2 (Stx2) that poses a huge threat to human and animal intestinal health. Production of Stx2 requires expression of stx2 gene, which is located in the genome of lambdoid Stx2 prophage. Growing evidence has implicated that many commonly consumed foods participate in the regulation of prophage induction. In this study, we aimed to explore whether specific dietary functional sugars could inhibit Stx2 prophage induction in E. coli O157:H7, thereby preventing Stx2 production and promoting intestinal health. We demonstrated that Stx2 prophage induction in E. coli O157:H7 was strongly inhibited by L-arabinose both in vitro and in a mouse model. Mechanistically, L-arabinose at doses of 9, 12, or 15 mM diminished RecA protein levels, a master mediator of the SOS response, contributing to reduced Stx2-converting phage induction. L-Arabinose inhibited quorum sensing and oxidative stress response, which are known as positive regulators of the SOS response and subsequent Stx2 phage production. Furthermore, L-arabinose impaired E. coli O157:H7 arginine transport and metabolism that were involved in producing Stx2 phage. Collectively, our results suggest that L-arabinose may be exploited as a novel Stx2 prophage induction inhibitor against E. coli O157:H7 infection.

Enterohaemorrhagic E. coli utilizes host- and microbiota-derived L-malate as a signaling molecule for intestinal colonization

“…L-Arabinose can improve intestinal health by manipulating the composition of the gut microbiota 61 . A recent study found that L-arabinose inhibits Shiga toxin type 2-converting bacteriophage induction in EHEC O157:H7 62 . Lithocholic acid and deoxycholic acid are secondary bile acids that are prevalent in the cecum and colon of mice and humans 63,64 .…”