A secret(e) weapon for food poisoning

Abstract

Microbiology![Figure][1] Listeria monocytogenes secrete a toxin that allows them to overwhelm good gut microbes. CREDIT: SCIENCE PICTURE CO/SCIENCE SOURCE Trillions of microbes reside in our gut, producing essential nutrients and defending gut integrity. So how do a few incoming pathogens compete against these masses to establish an infection? Some strains of the bacteria Listeria monocytogenes cause gastroenteritis, which can be fatal in the immunocompromised and in pregnant women. Studying mice, Quereda et al. found that a virulent strain of L. monocytogenes produces a toxin called listeriolysin S, but only when it is in the gut. The toxin led to changes in the abundance of acetate- and butyrate-producing gut resident microbes in L. monocytogenes –infected mice. These short-chain fatty acids can inhibit L. monocytogenes growth, implying that L. monocytogenes expresses the toxin to overwhelm resident microbial competition. Proc. Natl. Acad. Sci. U.S.A. 10.1073/pnas.1523899113 (2016). [1]: pending:yes