Escherichia coli strains associated with gastroenteritis in infants with special reference to a hospital outbreak due to E. coli type 111; B4.

Since 1952 specimens of stool from infants have been examined for Escherichia coli types 111;B4 and 55;B5. In 1953 the examination of these specimens was extended to include E. coli types 26;B6, 86;B7, 125, and 126. E. coli type 111;B4 was identified 156 times from 138 infants varying in age from newborn to one year. These strains could be separated into the three serological groups described by Kauffmann. There were 33 of subtype 111;B4;2, six of 111;B4;12, and 103 non-motile strains without H antigen. The 111;B4;2 cultures were salicin negative and resistant to streptomycin, whereas 111;B4;12 cultures were salicin positive and sensitive to streptomycin. Subtype 111;B4;2 was responsible for a hospital outbreak of gastro-enteritis in which the organism was isolated from the feces of 25 infants. Isolations of the five other types totalled 18 from 15 patients. Ninety-five per cent of the patients from whom the six E. coli types were isolated had a history of diarrhea of more or less severity.