Role of Probiotics in Helicobacter pylori Eradication: Lessons from a Study of Lactobacillus reuteri Strains DSM 17938 and ATCC PTA 6475 (Gastrus®) and a Proton-Pump Inhibitor

Background Meta-analyses involving >4000 subjects with probiotics added to antimicrobial Helicobacter pylori eradication therapy have reported a mean increase in the eradication rate of 12 to 14%. It is unclear how to translate that result into clinical practice. Aim To evaluate whether administration of Lactobacillus reuteri plus a PPI without antibiotics would eradicate H. pylori infections. Methods This was a double-blind placebo-controlled randomized 2-site study of L. reuteri (Gastrus®) at a dose of 2 × 108 CFU, 7 times per day, or matching placebo plus 20 mg pantoprazole b.i.d. for 4 weeks. Cure was defined by negative 13C-UBT, 4 weeks after therapy. Sample size required ≥50% cure rates for using probiotics as a clinically useful monotherapy. Results Recruitment was halted after 56 subjects because of the low cure rate; there were 8 dropouts; 48 subjects completed therapy (71% women, average age 49 years). The cure rates per protocol were 3/24 (12.5%; 95% CI 2.6–32%) with L. reuteri vs. 1/24 (4.1%) with placebo. Side effects (most often diarrhea) occurred infrequently (in 5/28 vs. 3/28; active vs. placebo therapy) (P=0.53). Conclusion L. reuteri plus a PPI therapy was unable to provide a clinically important rate of H. pylori eradication. The cure rate albeit low (12.5%) was essentially identical to that achieved when probiotics were added to antibiotic therapy. The incremental improvement was additive and independent of antimicrobial resistance or antibiotics use. Probiotics can reliably increase the cure rate to ≥90% only in regimens achieving cure rates of ∼80%. This trial is registered with NCT03404440.