Interactions of pathogenic Escherichia coli with Gut Microbiota

Abstract

The composition of gut microbiota (GM) plays a key role in the defense against pathogenic species of Escherichia coli, such as enterohemorrhagic E. coli (EHEC) and enteropathogenic E. coli (EPEC). The symbiotic relationship between the commensal microbiota and the host can be interrupted when the microbial composition is altered. Two of the most common threats to the balance of the microbiota that lead to dysbiosis are infectious diseases and antibiotic treatment. Crosstalk between GM and enteric pathogens includes nutrients availability and alterations in the mucus layer or in the oxygen metabolism. Especially in the Americas, the existence of co-infections with other pathogenic microorganisms (bacteria, parasites, or viruses) is a very important condition that has an impact on the outcome of EHEC infections. The integration between “omics” techniques offers a unique opportunity to dissect the metabolic and cellular processes of microbiota and to determine the components involved in the crosstalk between the pathogen and the host. Using these tools, several reports have associated the higher incidence of EHEC infections in children with a lesser maturity and a lower diversity in the composition of GM compared to adults. This overview is intended to show how much has been studied about the net interactions between EHEC and GM. However, the mechanisms by which the GM changes in response to virulence factors, to enhance host defense or conversely to exacerbate multi-organ damage, merit further investigations.