Colonization of the human gastrointestinal tract by the lactic acid bacteria 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. L. reuteri was ingested at a dosage of 109 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 L. reuteri were based on biochemical properties and a gene-based method (RiboPrint system). No subject was colonised with L. reuteri before the start of the study. Live L. 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. L. reuteri was identified at the strain level in the colon biopsies from one subject.

Conclusion:

The daily consumption of L. 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 L. reuteri strain cultivated from the colon biopsies.

Reference

Björkman P. (1999) Colonization of the human gastrointestinal tract by the lactic acid bacteria Lactobacillus reuteri. M.Sc. thesis, Dept. of Food Technology, University of Helsinki, Finland. (Abstract in English, the thesis is in Finnish.)