During the fall and winter months of 1955-1956, a study was carried out to determine the possible association of enteropathogenic forms of Escherichia coli (EPEC) with diarrheal diseases in infants and children admitted to the Los Angeles County General Hospital.1 The results of this survey suggested the presence of an endemic infection in the community with EPEC serotypes, predominantly O111:B4 Furthermore, the evidence pointed to a secondary spread on the infant wards in the hospital, where greater numbers of infants of susceptible age accumulated.
A second study, covering the early summer months of 1956, was undertaken. However, the serological methods of identification have been extended to conform to the criteria defined by Kauffmann2 and recently emphasized by Ewing.3 Despite the fact that earlier recognition of the disease, isolation, and prompt therapy are part of our program now, the EPEC serotypes continue to be seen in approximately