Growth advantage of Escherichia coli O104:H4 strains on 5-N-acetyl-9-O-acetyl neuraminic acid as a carbon source is dependent on heterogeneous phage-Borne nanS-p esterases

We detected and characterized five heterogeneous phage-borne nanS-p alleles in the genome of E. coli O104:H4 outbreak strain LB226692 by in silico analysis of its genome. Furthermore, successive deletion of all nanS-p alleles, subsequent complementation with recombinant NanS-p13-His, and in vitro co-culturing experiments with the commensal E. coli strain AMC 198 were conducted. We could show that nanS-p genes of E. coli O104:H4 are responsible for growth inhibition of strain AMC 198, when Neu5,9Ac2 was used as sole carbon source in co-culture. The results of this study let us suggest that multiple nanS-p alleles may confer a growth advantage by outcompeting other E. coli strains in Neu5,9Ac2 rich environments, such as mucus in animal and human gut.