The clonal nature of enteropathogenic Escherichia coli strains.

Enteropathogenic Escherichia coli belonging to O groups O111 and O55 and isolated from cases of infantile diarrhea in 26 countries all over the world during 1950-1960 were examined for their outer-membrane protein (OMP) patterns; nine O:H serotypes of O111 and 11 serotypes of O55 were represented. Characteristic biotypes have earlier been described as closely associated with the most common O:H serotypes: O111:H2, O111:H12, O55:H6, and O55:H7. Different OMP patterns characterized each of the common O:H serobiotypes. The OMP patterns can be looked upon as another set of stable phenotypic characters in addition to the serotype antigens and the fermentative characters. The description of geographically widely spread, stable sero-/bio-/OMP types supports the concept that the typical enteropathogenic E coli strains also have a clonal connection.