The expression of an R3 lipopolysaccharide-core by pathotypes of Escherichia coli

Aims:  To investigate the incidence of an R3 lipopolysaccharide (LPS)-core amplicon in a range of pathotypes of Escherichia coli, including Verocytotoxin-producing E. coli (VTEC), enteroaggregative E. coli (EAggEC) and enteropathogenic E. coli (EPEC). Methods and Results:  A total of 100 strains of E. coli belonging to a range of pathotypes, including 41 strains of VTEC, were screened for the genes encoding the R3 LPS-core using PCR. Fifty-four per cent produced an amplicon with the R3 primer set. Of the 41 VTEC, 66% had an R3 LPS-core with a PCR product being observed with all strains belonging to serotypes O26:H11, O111ac:H- and O145:H25. However, 46% of enteroaggregative E. coli and 50% of enteropathogenic E. coli were also shown to have an R3 LPS-core structure. Conclusions:  Strains with an R3 LPS-core are widely distributed within the species E. coli. Significance and Impact of the Study:  Strains of E. coli with an R3 LPS-core structure appear not to be associated with a specific pathotype.