Vitamin B12 Uptake by the Gut Commensal Bacteria Bacteroides thetaiotaomicron Limits the Production of Shiga Toxin by Enterohemorrhagic Escherichia coli

Toxins

Charlotte Cordonnier¹  Guillaume Le Bihan²  Jean-Guillaume Emond-Rheault²  Annie Garrivier¹  Josພ Harel²  Grégory Jubelin¹ 

[1] INRA, UR454 Microbiologie, F-63122 Saint-Genès-Champanelle, France;Groupe de Recherche sur les Maladies Infectieuses du Porc (GREMIP), Centre de Recherche en Infectiologie Porcine et Avicole (CRIPA), Université de Montréal, Faculté de Médecine Vétérinaire, C.P. 5000, Saint-Hyacinthe, QC J2S 7C6, Canada;

关键词: enterohemorrhagic Escherichia coli;    Shiga toxin;    Bacteroides thetaiotaomicron;    vitamin B₁₂;   

DOI  :  10.3390/toxins8010014

来源: mdpi

【 摘 要 】

Enterohemorrhagic Escherichia coli (EHEC) are foodborne pathogens responsible for the development of bloody diarrhea and renal failure in humans. Many environmental factors have been shown to regulate the production of Shiga toxin 2 (Stx2), the main virulence factor of EHEC. Among them, soluble factors produced by human gut microbiota and in particular, by the predominant species Bacteroides thetaiotaomicron (B. thetaiotaomicron), inhibit Stx2 gene expression. In this study, we investigated the molecular mechanisms underlying the B. thetaiotaomicron-dependent inhibition of Stx2 production by EHEC. We determined that Stx2-regulating molecules are resistant to heat treatment but do not correspond to propionate and acetate, two short-chain fatty acids produced by B. thetaiotaomicron. Moreover, screening of a B. thetaiotaomicron mutant library identified seven mutants that do not inhibit Stx2 synthesis by EHEC. One mutant has impaired production of BtuB, an outer membrane receptor for vitamin B₁₂. Together with restoration of Stx2 level after vitamin B₁₂ supplementation, these data highlight vitamin B₁₂ as a molecule produced by gut microbiota that modulates production of a key virulence factor of EHEC and consequently may affect the outcome of an infection.

【 授权许可】

CC BY   
© 2016 by the authors; licensee MDPI, Basel, Switzerland.