Benefits
Gut recovery support: shorter loose-stool spells in young children
In a pooled analysis of six randomized trials in children aged 3 months to 12 years with acute diarrhea, adding B. clausii to oral rehydration shortened episodes by about 9 hours and hospital stays by under a day. Only one trial was double-blind, results varied widely between trials, and the analysis was funded by Sanofi. A double-blind trial of a different strain found a similar small gain.
Digestive comfort during an antibiotic course
In a double-blind trial of 120 adults taking one week of antibiotics for H. pylori, those who also took B. clausii three times daily for 14 days had less nausea, diarrhea and upper stomach pain than those on placebo. Eradication rates and adherence did not differ. An Asian expert panel, whose members received Sanofi fees, also lists it as an option during antibiotic use.
Acid-resistant spore form
B. clausii is taken as dormant spores. Trial authors describe the Enterogermina spores as highly resistant to stomach acid and to most antibiotics, with listed exceptions that include vancomycin, sulfonamides and trimethoprim. This resistance is the reason it is given during antibiotic courses rather than only afterwards.
Immune support in young children
In a randomized pilot of 80 children with frequent respiratory infections, Enterogermina twice daily for 3 months shortened infection episodes (11.7 vs 14.4 days) compared with untreated controls, with no placebo. A placebo-controlled trial in 90 children found fewer, shorter infections and higher salivary IgA, but used strain UBBC-07, not Enterogermina, and was run by the strain's maker.
Mechanism of action
Spores that survive stomach acid and many antibiotics
The four Enterogermina strains each resist different classes of antibiotics, and the spores are described as resistant to gastric acid. The trial authors list exceptions: sulfonamides and trimethoprim, some aminoglycosides and nitrofurans, penicillins combined with beta-lactamase inhibitors, and vancomycin.
Germination and colonization in the intestine
After passing the stomach, the spores are described as able to germinate and colonize the intestine even while antibiotics are being taken. Proposed actions include occupying free space on the gut lining and competing with other bacteria for attachment.
Antimicrobial substances (proposed)
B. clausii is described as releasing peptide antibiotics and enzymes that act mainly against some other bacteria. This is a proposed mechanism, not a demonstrated clinical effect in people.
Immune signalling (proposed)
In the placebo-controlled children's trial of strain UBBC-07, salivary IgA rose and IgE fell in the probiotic group. The authors suggest a rebalancing of immune responses, but this was not tested directly.
Clinical trials
Systematic review and meta-analysis of six randomized trials (2007 to 2015) of B. clausii plus oral rehydration versus oral rehydration alone, with or without zinc. Only one trial was double-blind; three were published only as an abstract, dissertation or clinical study report. Funded in full by Sanofi. (Ianiro et al. 2018, Nutrients)
919 children aged 3 months to 12 years with acute diarrhea in Italy, Kenya, the Philippines and India; mostly 2 billion spores twice daily for 5 days.
Diarrhea lasted about 9 hours less with B. clausii (mean difference -9.12 h, 95% CI -16.49 to -1.75) and hospital stays about 0.85 days less. Stool frequency did not differ significantly. Results varied widely between trials (I2 63% for duration).
Randomized, double-blind, placebo-controlled trial of B. clausii (2 billion spores three times daily for 14 days) added to one week of rabeprazole, clarithromycin and amoxicillin. (Nista et al. 2004, Aliment Pharmacol Ther)
120 adults testing positive for H. pylori, without symptoms.
Nausea, diarrhea and upper stomach pain were less common, and nausea and diarrhea less intense, with B. clausii than with placebo. Adherence and eradication rates did not differ between groups.
Double-blind, randomized, placebo-controlled trial at two outpatient sites in India of a different commercial strain (UBBC-07, not Enterogermina), given twice daily for 5 days with oral rehydration. Two of the four authors work for the strain's maker, Unique Biotech. (Sudha et al. 2019, Benef Microbes)
Children aged 6 months to 5 years with acute diarrhea.
Diarrhea lasted 75.7 hours with the probiotic versus 81.6 hours with placebo, and by day 4 stools were less frequent (3.5 vs 4.6 a day). Vomiting and fever duration did not change.
Randomized, single-blind pilot study with an untreated control group and no placebo; one 2 billion spore vial twice daily for 90 days, then 3 months of follow-up. (Marseglia et al. 2007, Ther Clin Risk Manag)
80 children (mean age 4.3 years) with recurrent respiratory infections.
Infection episodes were shorter with B. clausii during treatment (11.7 vs 14.4 days) and at follow-up (6.6 vs 10.9 days). Adverse events were similar in both groups.
Double-blind, randomized, placebo-controlled trial of strain UBBC-07 (2 billion spores twice daily for 3 months, then 3 months of follow-up). Four of the seven authors work for the strain's maker. (Madempudi et al. 2022, Benef Microbes)
90 children aged 4 to 7 years with upper respiratory tract infections.
The probiotic group had fewer, shorter and less severe infections than placebo, lower IgE and higher salivary IgA. This was not the Enterogermina product.