Enterohemolysin, a new type of hemolysin produced by some strains of enteropathogenic E. coli (EPEC)

42 Escherichia coli O26 strains which had been isolated at geographically different places and over a long time period were examined for hemolysin synthesis. 17 of these were found to be hemolysin-negative, nine strains were found to produce plasmid encoded alpha-hemolysin and 16 strains were shown to produce a phenotypically different hemolysin. This new type of hemolysin was called enterohemolysin and found to be genetically and immunologically non-related with the already described E. coli alpha-hemolysin. Enterohemolytic E. coli were not found in feces of 200 healthy infants under the age of two years. However, four E. coli O111 strains, one O121:H- and one O25:K5:H- strain, all from infants with diarrhoea were also enterohemolysin producers.