Adaptation aux variations d'environnement des souches commensales d'escherichia coli

We studied variations of characteristics of human and animal commensal E. Coli to variations of their hosts environment. Prevalence of antibiotic resisance, of integron, of mercury resistance, phylogenetic repartition and intra-host diversity were selected; More animals were ling near humans, more their commensal E. Coli were resistant and more the prevalence of integron was high, while the intra-host diversity decreased. In human commensal E. Coli, characteristics of isolates from expatriates living in French Guyana, were found intermediate between those found in isolates from residents in metropolitan france and those found in natives living permanently in french guyana, probably the result from their living in an environment close to that of the native Guyaneses but with a way of life close to that of residents living in metropolitan france. In conclusion our results suggest that the environment strongly influence the composition of the commensal intestinal flora of humans and animals.