Résumé
The E. coli Nissle strain has been used as a probiotic for more than a century under the name Mutaflor®. It is used for various indications such as diarrhea, constipation or inflammatory bowel diseases. The probiotic effect of this strain is partly due to its antagonistic activity against phylogenetically related bacteria, whether commensal or pathogenic. This antagonistic activity is possible thanks to the production of microcins siderophores, which are antimicrobial peptides synthesized by genes carried by different genomic islands.Previous studies have shown that the microcin biosynthetic pathway is adapted to the anoxic intestinal lumen where the wild type E. coli Nissle strain is found.We were therefore interested in the impact of oxygen bioavailability on the production of its siderophore-microcins.