Dysbiosis in the inflamed intestine: chance favors the prepared microbe.

The bacterial microbiota of the human large bowel is a complex ecosystem consisting of several hundred, mostly anaerobic, species. To maintain colonization of the gut lumen and maximize growth in the presence of nutritional competitors, highly diverse metabolic pathways have evolved, with each microbe utilizing a different "winning strategy" for nutrient acquisition and utilization. Conditions and diseases leading to intestinal inflammation are accompanied by a severe disruption the microbiota composition characterized by an expansion of facultative anaerobic Enterobacteriaceae. Here, we review evidence that the local inflammatory response creates a unique nutritional environment that is conducive to a bloom of bacterial species whose genomes encode the capability of utilizing inflammation-derived nutrients.