Probiotics in Gastrointestinal Disorders

Prevention of C. difficile Infection During Antibiotic Therapy

The American Gastroenterological Association (AGA) conditionally recommends specific probiotic strains, including Saccharomyces boulardii (1g or 3×10¹⁰ CFU/day), to reduce the risk of C. difficile infection in adults and children receiving antibiotics, with a reduction in risk by 59% 1, 2
The AGA also recommends a two-strain combination of Lactobacillus acidophilus CL1285 and L. casei LBC80R, which reduces the risk by 78% 2
A three-strain combination of L. acidophilus, L. delbrueckii subsp bulgaricus, and Bifidobacterium bifidum reduces the risk by 65% 2
A four-strain combination of L. acidophilus, L. delbrueckii subsp bulgaricus, B. bifidum, and Streptococcus salivarius subsp thermophilus reduces the risk by 72% 2

Probiotics are absolutely contraindicated in immunocompromised patients due to the risk of bacteremia or fungemia 2
Patients with severe underlying illness should avoid probiotics, as the potential harms may outweigh benefits 1

The AGA makes no recommendation for probiotics in treating active C. difficile infection, and they should only be used in clinical trials 1, 3
S. boulardii showed potential benefit in one study, reducing diarrhea recurrence with a relative risk of 0.59, but the overall certainty of evidence remains low 4

The AGA conditionally suggests a specific 8-strain combination of probiotics, including L. paracasei subsp paracasei, L. plantarum, L. acidophilus, L. delbrueckii subsp bulgaricus, B. longum subsp longum, B. breve, B. longum subsp infantis, and S. salivarius subsp thermophilus, for adults and children with pouchitis 1, 3

The AGA recommends probiotics for IBS only within clinical trials, and not for routine clinical practice, due to very low evidence quality 1, 3, 5
Only two formulations had multiple trials: S. boulardii (3 studies, 232 adults) showed no difference in abdominal pain scores versus placebo, and an 8-strain combination (2 studies, 73 adults) decreased abdominal pain by 3.78 points on a visual analog scale, but with unclear bias risk 6, 7, 8

The AGA recommends using probiotics only in clinical trials, and not for routine practice, for both Crohn's disease and ulcerative colitis, due to insufficient evidence 1, 3, 5

The AGA conditionally recommends against probiotics for children with acute gastroenteritis in the United States and Canada, with moderate evidence quality 1, 8, 7
Two large, high-quality North American multicenter trials found no benefit of probiotics in reducing diarrhea duration, unlike studies from other global regions 6, 8, 7

The AGA conditionally suggests specific probiotic strains or combinations, including Bifidobacterium animalis subsp lactis, Lactobacillus reuteri, and L. rhamnosus, to prevent NEC in preterm infants less than 37 weeks gestational age, with moderate to high evidence quality 1, 3, 5

The probiotic literature suffers from profound heterogeneity, including strain specificity, inconsistent harms reporting, manufacturing variability, and publication bias, which limits clinical application 1, 6, 8, 7