Molecular typing and phylogenetic analysis of enteroinvasive Escherichia coli using the fliC gene sequence

Non-motile enteroinvasive Escherichia coli (EIEC) is serotyped based only on O antigen polymorphism, since H antigen epitopes, present on the flagellins, cannot be characterised in these bacteria. In this study, we demonstrate the presence of the flagellin-coding fliC gene in non-motile EIEC strains. Moreover, we were able to group the 11 most common non-motile EIEC serotypes into six different RFLP patterns of the fliC gene. Amplicons representing each RFLP pattern were sequenced. Sequencing data were used to construct a phylogenetic tree which showed two main clusters: one sharing similarity with Shigella dysenteriae and pathogenic E. coli, and the other being closer to non-pathogenic E. coli.