Persistence of Colonization of Human Colonic Mucosa by a Probiotic Strain, <i>Lactobacillus rhamnosus</i> GG, after Oral Consumption

TLDR

Lactobacillus rhamnosus GG is a well‑studied probiotic with documented benefits for gastrointestinal disorders. The study aimed to show that strain GG attaches to human colonic mucosa and persists after stopping intake. Participants consumed a whey drink fermented with GG for 12 days, with fecal samples collected before, during, and after consumption, and strain identification performed by colony morphology, lactose fermentation, and PCR. Colonial and biopsy analyses revealed GG attachment to colonic mucosa, which remained for over a week after cessation, indicating that fecal sampling alone cannot assess probiotic colonization.

Abstract

ABSTRACT Lactobacillus rhamnosus GG is one of the most thoroughly studied probiotic strains. Its advantages in the treatment of gastrointestinal disorders are well documented. The aim of the present study was to demonstrate with colonic biopsies the attachment of strain GG to human intestinal mucosae and the persistence of the attachment after discontinuation of GG administration. A whey drink fermented with strain GG was fed to human volunteers for 12 days. Fecal samples were collected before, during, and after consumption. L. rhamnosus GG-like colonies were detected in both fecal and colonic biopsy samples. Strain GG was identified by its characteristic colony morphology, a lactose fermentation test, and PCR. This study showed that strain GG was able to attach in vivo to colonic mucosae and, although the attachment was temporary, to remain for more than a week after discontinuation of GG administration. The results demonstrate that the study of fecal samples alone is not sufficient in evaluating colonization by a probiotic strain.