Due to the increase in antibiotic resistance and side effects of H. pylori eradication regimens, alternative strategies for the treatment of H. pylori infection are being considered. The aim of this study was to evaluate the efficacy of probiotic as an adjuvant in quadruple therapy for H. pylori eradication compared with placebo

This randomized, double-blind, controlled trial was conducted on 450 patients with confirmed H. pylori infection. We randomly allocated patients (1:1) to receive probiotic (Lactobacillus ruteri, 100mg) or placebo as an adjuvant in quadruple therapy with bismuth subcitrate 240mg, pantoprazole 40mg, amoxicillin 1000 mg and clarithromycin 500mg all twice daily for 14 days. The primary outcome of the study was the H. pylori eradication rate at eight weeks after the end of treatment using 14C-urea breath test. The secondary endpoint of study was patient-reported side effects of drugs

H. pylori eradication rates were higher in the probiotic group, compared to placebo, but this difference was not statistically significant, according to both intention-to-treat (78.7% (95 % CI; 71.24 - 86.16) versus 72% (95 % CI; 64.9-79.1), respectively) and per-protocol (80.1% (95 % CI; 73.7 – 86.5) versus 75.2 %( 95 % CI; 68.4 – 82), respectively). About 69.7% of patients in the probiotic group experience side effects compared to 98.6% in the placebo group that was statistically significant (P-value <0.001). Headache and all gastrointestinal adverse events except constipation were significantly lower in the probiotic group compared to placebo (P-value <0.001).

Although Lactobacillus ruteri as an adjuvant of 14-day quadruple therapy lead to a higher eradication rate of H. pylori infection compared to placebo, but this difference was not statistically significant. However, Lactobacillus ruteri reduced the frequency of drug-associated adverse events.