Local and serum antibody response in full–term and premature infants after artificial colonization of the intestine with E. coli strain Nissle 1917 (Mutaflor®)

After oral colonization with the non–enteropathogenic E. coli strain Nissle 1917 ( E. coli SK22, Mutaflor®) in 22 full–term and 9 premature infants, the strain was detected in the stools from day 3 after administration and persisted throughout the study. The presence of E. coli SK22 in the intestine evoked a pronounced local, as well as a serum antibody response. The anti–SK22 antibodies of IgA and IgM isotypes in stool filtrates and in serum were significantly higher in colonized infants than in controls. Full–term infants had higher titers of IgA and IgM isotypes in stool filtrates than premature infants. The specific response against E. coli SK22 was higher than the antibody response against a control E. coli strain.