No document available.
Abstract :
[en] Several virulence factors are expressed by extra-intestinal Escherichia coli, which enable them to effectively colonize and survive in diverse locations. Of these factors, the K1 capsular type has been found to be involved in several types of human infections, including meningitis, urinary tract infections and bloodstream infections. These strains can also be found in animals and particularly in poultry where they are responsible for colibacillosis. Phage therapy is a promising alternative to antibiotics and the understanding of the bacterial resistance mechanisms to phages has implications for the development of phage-based therapies. The objective of this study was to investigate the resistance of E. coli K1 to ULINTec4, a K1-dependent bacteriophage. Resistant bacterial colonies were isolated from an avian pathogenic E. coli strain APEC 45 and the human strain C5, both previously exposed to the ULINTec4. After confirmation of their resistance, the individual growth of the bacterial isolates was analyzed in the presence and absence of phages using growth curve analysis. One of the resistant isolates exhibited a significantly slower growth rate suggesting the presence of a resistance mechanism altering its fitness. After genomic sequencing using Nanopore technology, the comparative genomic analysis revealed the presence of insertion sequences in the capsular genes cluster. In conclusion, a phage resistance mechanism was detected at the genomic level and decreased the fitness of E. coli K1 in-vitro. Further research are now needed to identify other resistance mechanisms at the genomic level. The project was financially supported by Wallonia in the framework of the call for projects organised by BioWin competitiveness cluster (Project Inteliphages)
