Persistence of Lactobacillus reuteri in the human intestinal tract

This open trial investigated the colonisation and persistence of Lactobacillus reuteri DSM 17938 after daily or alternate day dosing.

Healthy adult volunteers ate pudding with Lactobacillus reuteri(10^9 CFU) daily (n = 9) or on alternate days (n = 9) during 7 days. Faecal samples were collected on dosing days and after dosing ended (day 13–15 and day 20–22), and analyzed for Lactobacillus reuteri.

The Lactobacillus reuteri count increased significantly in both groups during the week of ingestion and fell in both groups 1 week after dosing ended. Faecal levels on days 2–4 were of the same magnitude as on days 5–7 for both groups. Whether alternate day dosing had any effect on different parameters of presumptive clinical outcome measures was not studied.

Relevant faecal counts of Lactobacillus reuteri were reached already after 2–4 days of supplementation. Alternate day intake achieved a colonisation equivalent to daily intake. Once dosing stopped there was a rapid decline in faecal counts.

Survival of Lactobacillus reuteri and Lactobacillus rhamnous GG in the human gastrointestinal tract

This randomised, double blind, placebo-controlled study sought to determine the survival ofLactobacillus reuteri DSM 17938 and Lactobacillus rhamnosus GG when ingested as part of a low-fat probiotic spread in 42 healthy human volunteers.

Volunteers were randomly assigned to one of three treatment groups provided with placebo spread (n=13), spread with a target dose of 1 x 10^9 CFU of Lactobacillus reuteri DSM 17938 (n=13), or spread with a target dose of 5 x 10^9 CFU of Lactobacillus rhamnosus GG (n=16) daily for 3 weeks. A significant increase in bacterial counts for both strains was recorded in faecal samples after 3 weeks of daily consumption of the low-fat probiotic spread.

Conclusion: Low-fat spread is a suitable carrier for these probiotic strains.

Lactobacillus reuteri in breast milk and infant stool in relation to oral intake

This prospective, randomised, double blind, placebo-controlled study identified factors affecting the prevalence of Lactobacillus reuteri in the faeces and breast milk of 232 mothers with a history of atopic disease, and in the faeces of their babies after oral supplementation with Lactobacillus reuteri ATCC 55730.

Women were randomly assigned to take either Lactobacillus reuteri or placebo for the last 4 weeks of their pregnancy. Their babies continued with the same study product from birth until 12 months of age. The prevalence of Lactobacillus reuteri was higher in the faeces of infants whose mothers had taken the active supplement compared with those whose mothers had taken placebo.

The highest prevalence was recorded at 5–6 days of age (82% in treated vs. 20% in placebo; p<0.001). The first expressed breast milk (colostrum) was positive for Lactobacillus reuteri in 12% of the mothers given Lactobacillus reuteri and in 2% of mothers in the placebo group. Breast-feeding seemed to reduce faecal Lactobacillus reuteri counts while antibiotics did not appear to have any effect. Lactobacillus reuteri supplementation did not appear to affect bifidobacteria or C. difficile colonisation.

Lactobacillus reuteri can be detected in breast milk after oral supplementation to the mother and in almost all infants after oral supplementation during the first year of life. Lactobacillus reuteri can also occasionally be detected in the faeces of untreated infants.


Lactobacillus reuteri can be detected in breast milk after oral supplementation to the mother and in almost all infants after oral supplementation during the first year of life. Lactobacillus reuteri can also occasionally be detected in the faeces of untreated infants.

Colonization and immunomodulation by Lactobacillus reuteri in the human gastrointestinal tract

This was an open study with the objective to investigate the colonisation of Lactobacillus reuteri, as detected by the genebased so-called FISH method, as well as effects on the immune system.

10 healthy subjects and 9 with ileostomy ingested Lactobacillus reuteri ATCC 55730 in a tablet (4 x 10^8 CFU daily) for 28 days. Tissue samples (biopsies) were taken from the gastric mucosa and from the first part of the small intestine (the duodenum) in 10 of the subjects and from the distal part of the small intestine (the ileum) in 9 of the subjects. The biopsies were taken prior to the start of Lactobacillus reuteriintake and after 28 days’ of intake.

At the end of the study period, all 10 healthy subjects were colonized in the stomach and/or duodenum. All 6 subjects in whom a biopsy could be taken from the ileum (of 9 with ileostomy) were colonized. Stool samples also verified colonisation, up to 2 to 4 weeks after the last day of Lactobacillus reuteri intake. Effects on the immune system in the intestinal mucosa were shown as a significantly increased number of B lymphocytes (CD20-positive cells) in the duodenum and the number of T lymphocytes (CD4-positive cells) in the ileum.

Conclusion: Dietary supplementation with Lactobacillus reuteri induces a significant colonisation of the stomach, duodenum and ileum of healthy humans, and this is associated with significant alterations of the immune response in the gastrointestinal mucosa.

Colonization of the human gastrointestinal tract by Lactobacillus reuteri

This was an open study with the objective to study the colonisation of the colon by Lactobacillus reuteri ATCC 55730, in ten adult patients undergoing a colonoscopy examination.

Lactobacillus reuteri was ingested at a dosage of 10^9 CFU/day, as yoghurt (5 patients) or as probiotic fruit juice (5 patients) for 12 days before the colonoscopy. Faecal samples were analysed before and after 12 days of consumption of the probiotic foods. Biopsies from all three parts of the colon were sampled on day 12. Identification methods for Lactobacillus reuteri were based on biochemical properties and a gene-based method (RiboPrint system). No subject was colonised with Lactobacillus reuteri before the start of the study.

Live Lactobacillus reuteri cells were found on day 12 in faecal samples from 3/5 subjects in the yoghurt group and in all five in the juice group. Lactobacillus reuteri was identified at the strain level in the colon biopsies from one subject.


Conclusion: The daily consumption of Lactobacillus reuteri in yoghurt or fruit juice for 12 days resulted in successful colonisation of 80% of the study subjects, measured as live bacteria cells in faecal samples. One of the subjects also had the administered Lactobacillus reuteri strain cultivated from the colon biopsies.