Persistence of colonization of human colonic mucosa by a probiotic strain,Lactobacillus rhamnosus GG, after oral consumption

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 colon ic 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 da ys. Fecal samples were collected before, during, and after consumption. L. rhamnosus GG-like colonies were detected in both fecal and colonic biopsy s amples. Strain GG was identified by its characteristic colony morphology, a lactose fermentation test, and PCR This study showed that strain GG was ab le to attach in vivo to colonic mucosae and, although the attachment was te mporary, to remain for more than a week after discontinuation of GG adminis tration. The results demonstrate that the study of fecal samples alone is n ot sufficient in evaluating colonization by a probiotic strain.