The influence of artificial colonization withE. coli strain O83 on the intestinal flora in infants

Dominant bacterial strains present in stool (with particular emphasis onE. coli strains) were examined in 4 groups of healthy infants: breast-fed and bottle-fed, colonized withE. coli O83, and control (non-colonized) breast-fed and bottle-fed newborns. The presence of fimbriae was examined by hemagglutination, the P-fimbriae-bearing strains were tested by the PPA latex test. In addition, adherence to cell line HT-29 and serotyping was performed in selected strains. TheE. coli strain O83 was found to possess type 1 fimbriae. Fewer bacterial strains possessing type 1 fimbriae were found inE. coli O83-colonized infants (except the O83 serotype) than in control infants. TheE. coli O83 strain colonized significantly better the breast-fed than the bottle-fed infants; its higher adherence activity was demonstrated even in cell line HT-29. Finally, colonization withE. coli O83 influenced the character of microbial intestinal flora: the frequency of positiveE. coli isolates was significantly higher in colonized (both breast- and bottle-fed) than noncolonized infants.