Special Escherichia coli serotypes among enterotoxigenic strains from diarrhoea in adults and children.

106 enterotoxigenic Escherichia coli strains from children and adults from many parts of the world were serotyped for O and H antigens. Some O:H types, i.e. O6:H16, 08:H9, O15:H11, O25:H42, O78:H11 and O78:H12, were found repeatedly from different geographical locations. Some of these O:H serotypes were only found rarely among more than 20000 E. coli strains collected over many years from different locations and sources. It is suggested that these special O:H serotypes represent clones which have been selected to the special conditions in the small intestine and selected to carry the plasmids necessary to provoke diarrhoea.