Colonization resistance: metabolic warfare as a strategy against pathogenic Enterobacteriaceae

The intestine is home to a large and complex bacterial ecosystem (microbiota), which performs multiple beneficial functions for the host, including immune education, nutrition, and protection against invasion by enteric pathogens (colonization resistance). The host and microbiome symbiotic interactions occur in part through metabolic crosstalk. Thus, microbiota members have evolved highly diverse metabolic pathways to inhibit pathogen colonization via activation of protective immune responses and nutrient acquisition and utilization. Conversely, pathogenic Enterobacteriaceae actively induce an inflammation-dependent disruption of the gut microbial ecosystem (dysbiosis) to gain a competitive metabolic advantage against the resident microbiota. This review discusses the recent findings on the crucial role of microbiota metabolites in colonization resistance regulation. Additionally, we summarize metabolic mechanisms used by pathogenic Enterobacteriaceae to outcompete commensal microbes and cause disease.

Automated summary

The intestine is a complex bacterial ecosystem that provides immune education, nutrition, and protection against pathogens. Symbiotic interactions between the host and microbiome occur through metabolic crosstalk, with microbiota inhibiting pathogen colonization through diverse metabolic pathways, while pathogens disrupt the microbiome to gain a metabolic advantage. This review discusses the role of microbiota metabolites in colonization resistance and the metabolic mechanisms used by pathogens to outcompete commensal microbes.