Colony incompatibility studies of enterotoxigenic Escherichia coli O126 isolated during one outbreak

Strains of heat-stable enterotoxin-producing Escherichia coli belonging to O group O126 isolated during an outbreak of gastroenteritis were studied by the colony incompatibility phenomenon. They were compared with other isolates of O126. All of the outbreak strains except one appeared related in these studies and were different from all other strains studied. The one different outbreak strain was isolated 6 weeks after all of the others and may represent some new factor. The study demonstrated the potential usefulness of monitoring strains during an outbreak for relatedness.