A breathtaking feat: to compete with the gut microbiota, Salmonella drives its host to provide a respiratory electron acceptor.

Salmonella is a common cause of food poisoning. However, after ingestion the pathogen has to compete with resident microbes that already occupy the intestinal lumen (microbiota), which poses a challenge for Salmonella to successfully colonize this niche. Recent data show that Salmonella elicits help from the host immune response to beat the competition. After arriving in the intestine, Salmonella elicits acute intestinal inflammation. The respiratory burst of neutrophils that transmigrate into the intestinal lumen during inflammation oxidizes endogenous sulfur compounds to generate a respiratory electron acceptor, tetrathionate. As a result, Salmonella can use tetrathionate respiration to outgrow the fermenting microbiota in the anaerobic environment of the gut, which promotes transmission of the pathogen. This principle might be used by other gut microbes and contribute to changes in the microbiota composition observed during inflammation.