Siderophore piracy as a resilience factor for Bacteroidetes during enteric pathogen infection

Resilient mechanisms are required for members of the gut microbiota to survive the drastic changes in nutritional environment in the large intestinal tract during intestinal inflammation. Bacterial resilience determines whether the microbiome maintains its structure and functions post perturbation. Despite being such an important facet of microbiome research, our understanding of the underlying mechanisms are limited. The availability of essential elements such as iron is reduced dramatically during intestinal inflammation due to host nutritional immunity. Previos studies have shown that many pathogenic bacteria employ high-affinity iron chelators termed siderophores to compete with the host for iron. However, it is currently unkown how gut commensal bacteria acquire this essential element in the inflamed intestine is largely unknown. Here, we show that members of the Bacteroidetes phylum encode a transporter system which enables the bacterium to utilize siderophores that are produced by other bacteria such as Salmonella enterica serovar Typhimurium, a phenomenon known as siderophore piracy. Siderophore piracy allows B. thetaiotaomicron to overcome iron limitation in the inflamed intestine and remain resilient during intestinal inflammation.