Bacterial supplementation in the irritable bowel syndrome. A randomised double-blind placebo-controlled crossover study

Background. Symptoms of at least a subgroup of patients with irritable bowel syndrome may be associated with an alteration in gut flora. Studies on bacterial based therapy have yielded mixed results. Aims. To determine if oral administration of the probiotic Lactobacillus casei strain GG under randomized placebo controlled conditions improves symptoms in irritable bowel syndrome patients with bloating related symptoms. Patients. A total of 25 patients with clinically confirmed irritable bowel syndrome (Rome criteria) were enrolled in the study. Methods, This was a randomised double-blind placebo-controlled crossover trial Lactobacillus GG was administered as enterocoated tablets constituting a daily dosage of 10(10)colony forming units. Symptoms were assessed by daily symptom diaries and periodic questionnaires. Results. Twenty-four patients were randomised; 19 (80%) female, mean age 40 years (range 24-60) mean duration of symptoms 4.9 years (range 0.5-18) Nineteen (80%) patients completed the study. No significant differences were found between Lactobacillus casei strain GG and placebo mean symptom scores for pain, urgency or bloating. A trend was noted, however: for a reduction in the number of unformed bowel motions on Lactobacillus casei strain GG treatment for patients with diarrhoea. Conclusions. Lactobacillus casei strain GG alone did not significantly improve symptoms in this irritable bowel syndrome subgroup. A "diarrhoea predominant" subgroup may warrant further investigation.