Studies of Infectious Agents in Infant Diarrhea

Abstract

Summary A study is presented in which the problem of acute gastroenteritis in infants is investigated by performance of bacteriologic, parasitologic and virologic analysis of 29 fecal samples collected from Puerto Rican infants with diarrheal disease. The study revealed 10 enteropathogenic Escherichia coli, one Shigella, one Salmonella, 4 pathogenic protozoa, and 15 viral agents. Ten strains of E. coli 01 through 024 were recovered from the same samples and included in the study as representative of non-enteropathogenic serotypes. The serologic response against these isolates was determined in every instance where this was possible. Bacterial substance antigenically related to the E. coli serotype present in the intestine was detected in the sera of several patients. Rises in hemagglutinin titer occurred to both pathogenic and “nonpathogenic” E. coli. A neutralizing antibody response was detected for 7 of the 15 virus isolates; 5 of the viral agents isolated are apparently new enteroviruses. Multiple infections were found in 39% of the cases on whom complete studies were undertaken. The study here presented indicates that the multiplicity of infectious agents in the intestinal flora of infants with diarrhea must be considered in any etiologic investigation of this problem.