Administration of the Probiotic Escherichia coli Strain A0 34/86 Resulted in a Stable Colonization of the Human Intestine During the First Year of Life.

Colinfant New Born (CNB) is an orally administered probiotic preparation containing the Escherichia coli strain A0 34/86, which is specially marketed for use in newborns and infants. Although the impact of different probiotics on the composition of the human gut microbiota has been previously described, the effects of E. coli probiotic consumption during infancy on the development of intestinal microbiota are not known. The effect of oral administration of CNB on the Enterobacteriaceae population was mapped using 16S rRNA gene sequencing in DNA samples isolated from the stools of one infant collected at 177 different time points during the first year of life. E. coli strains turnover was analyzed based on the detection of 26 genetic determinants, phylogroups, and pulsed-field gel electrophoresis (PFGE) analysis. Administration of CNB during the second and third month of life introduced the Escherichia genus to the infant's intestinal tract, and Escherichia became dominant among the Enterobacteriaceae family (p < 0.01). Genetic determinants, typical for probiotic E. coli A0 34/86 strain, were detected on the first day after application of CNB and persisted all year. In addition, nine transient E. coli strains were identified; these strains harbored different genetic determinants and showed different PFGE profiles. Transient strains were detected from 2 to 24 days in the stool samples. The first Escherichia colonizer originated from the application of the CNB probiotic preparation. Probiotic E. coli A0 34/86 successfully colonized the intestinal tract of an infant and became resident during the first year of life.