Characterization of enteroaggregative Escherichia coli isolated from outbreaks of diarrhoeal disease in England

Twenty-two strains of enteroaggregative Escherichia coli (EAggEC), isolated from four outbreaks of diarrhoeal disease in England, were examined for a range of phenotypic attributes including the ability to produce fimbriae, h aemolysins and siderophores, and cell-surface properties such as surface ch arge and hydrophobicity. Strains of EAggEC isolated from two of these outbr eaks belonged to a diverse range of serotypes and were heterogeneous in phe notype. Strains of EAggEC isolated from the other two outbreaks belonged pr edominantly to serotypes O86:H34 and O98:H-, respectively. Only two strains expressed fimbriae and two strains produced an 18 kDa membrane associated protein (MAP), suggesting that EAggEC express a range of adhesion mechanism s to produce the cell arrangement recognized as the 'stacked brick' formati on. The possible explanation for the diversity of EAggEC serotypes is discu ssed.