Abstract
Dietary supplements with lactic-acid producing microorganisms like Lactobacillus have been used to maintain or re-establish the 'ecological balance' of the intestinal microflora. The aim of the present investigation was to study the impact of probiotic products containing a strain of Lactobacillus paracasei spp. paracasei isolate F19 ( Lactobacillus F19) on the prevalence of lactobacilli (other than Lactobacillus F19), bifidobacteria and Clostridium difficile in the fecal microflora in elderly persons sero-positive for Helicobacter pylori and in children. Sixty-one healthy children and 30 elderly persons completed the study. They had been randomized into treatment and placebo groups. Children in the treatment group received gelatine capsules containing freeze-dried bacteria twice daily for 3 weeks and the older age group, a fermented milk product with Lactobacillus F19 twice daily for 12 weeks. Subjects in the placebo groups received similar products but with no active ingredients. Fecal samples were collected from the children before, during (at 2-3 weeks) and 2 weeks after the administration and from the elderly persons before, during (at 4 and 12 weeks) and 20 weeks after the start of the study. Samples were diluted and inoculated on selective agars for detection of lactobacilli, bifidobacteria and C. difficile. The numbers of Lactobacillus F19 increased significantly during the study period in both age groups. In six of 30 children and in one of 13 elderly persons, Lactobacillus F19 was detected 2 and 8 weeks, respectively, after the end of the administration period. No major changes occurred in the numbers of lactobacilli other than Lactobacillus F19 or of bifidobacteria in children, while there was a significant increase in the numbers of lactobacilli in elderly persons during the administration of Lactobacillus F19. In fecal samples of seven of 18 children, C. difficile was detected at the first sample occasion. Two weeks after the end of administration, C. difficile was detected in only four children. None of the elderly persons had any detectable C. difficile. No effect was observed on H. pylori infection measured by means of urea breath test. Lactobacillus F19 survived the passage through the gastrointestinal tract and remained in 8-20% of subjects for at least several weeks as a part of the normal microflora.