Monday, September 21, 2020

433 - Probiotic Promotes Pathogen Peacefulness

E. coli in lumen of organoid
From Pradhan and Weiss, 2020
mBio 11(4):e01470-20
CC BY 4.0

This episode: A probiotic can protect intestine-like cell growths from destruction by pathogens, but it can also be infected by a virus that makes it more harmful to intestinal cells!

Download Episode (6.9 MB, 10.1 minutes)

Show notes:
Microbe of the episode: Euphorbia yellow mosaic virus

News item

There are many strains of Escherichia coli. Some are pathogenic, in the gut or the urinary tract, and a subset of those are very dangerous, such as the enterohemorrhagic O157:H7 strain. Many others are commensals, living peacefully as part of our gut community. And some strains can be beneficial to the host, protecting from and reducing the severity of disease. One such strain is called E. coli Nissle.

This study used an advanced model of human intestines called organoids, where stem cells are induced to develop into hollow spheres of intestinal epithelium in which all cell types of a normal intestinal wall are represented. E. coli pathogens typically destroy these organoids and escape from inside, but Nissle was able to prevent this destruction and enable coexistence between the pathogen and the host cells. Nissle suffered for this protection though; O157:H7 carries a toxin-encoding phage that can infect and kill susceptible E. coli strains. Those Nissle cells that survived this infection could resist the phage, but were not as beneficial to the organoids due to the toxin they now produced.

Journal Paper:
Pradhan S, Weiss AA. 2020. Probiotic Properties of Escherichia coli Nissle in Human Intestinal Organoids. mBio 11(4):e01470-20.

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