Moving Parts

A common pathogen, the bacterium Salmonella enterica comes in many distinct forms, or serovars: most lead to unpleasant gastroenteritis, but some serovars, the typhoidal salmonellae, cause a more severe disease known as enteric or typhoidal fever. Despite sharing almost 90% of their genes, the typhoidal S. Paratyphi A (SPA) and non-typhoidal S. Typhimurium (STM) vary in how they behave inside cells cultured in the lab. After infecting a cell, STM are enclosed in specialised cellular compartments, Salmonella-containing vacuoles (SCVs), and downregulate genes associated with the flagellum, a structure bacteria use to swim around. By contrast, SPA (pictured in blue) maintain their flagella (in red), so can escape out of SCVs and move around. Alongside differences in metabolism and other virulence pathways, this enhanced mobility likely contributes to the more severe impacts of SPA infections. With no vaccine available and growing antibiotic resistance, understanding what makes SPA so dangerous could help suggest potential solutions.

Written by Emmanuelle Briolat

Emmanuelle Briolat

Writer

A researcher specialising in visual signals in Lepidoptera, camouflage and the effects of light pollution, Emmanuelle’s writing covers a range of topics, from biomedical research to children’s books about moth defences.

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• Image by Felix Scharte and Michael Hensel, Abt. Mikrobiologie, Universität Osnabrück
• Abt. Mikrobiologie, Universität Osnabrück, Osnabrück, Germany
• Image copyright held by Felix Scharte and Michael Hensel
• Research by Helit Cohen, Claire Hoede & Felix Scharte et al, published in PLOS Pathogens, April 2022