Background Bismuth is no longer available in Europe except as part of combination therapy. Lactobacillus reuteri has also been used as an adjuvant for Helicobacter pylori therapy. We aimed to investigate the efficacy of a b.i.d. quadruple therapy containing Pylera® or L reuteri for H pylori infection. Materials and Methods We performed two open‐label randomized pilot studies. Adult patients positive for H pylori were randomly assigned to b.i.d therapy with quadruple therapy containing bismuth (2 capsules of Pylera® plus 250 mg each of tetracycline and metronidazole for a total of 500 mg of each), or the same dose of antibiotics plus 2 × 108 CFU L reuteri DSM 17 938 plus 2 × 108 CFU L reuteri ATCC PTA 6475 (Gastrus®) once daily and pantoprazole 20 mg b.i.d. Regimens were given with meals for 10 days. Cure was defined by negative 13C‐UBT or stool antigen test. Results A total of 99 subjects (29% men) were enrolled; 92 completed the study. In the Pylera® group, H pylori infection was cured in 95.7%; 95% CI = 85%‐99% (44/46) PP and 88%; 95% CI = 75%‐95% (44/50) ITT vs. 84.8%; 95% CI = 71%‐95% (39/46) PP and 79.6%; 95% CI = 65%‐89% (39/49) ITT in the Gastrus® group, respectively. Cure rates in naїve patients were 100%; 95% CI = 85%‐100% (25/25) PP with Pylera®, and 89.7%; 95% CI = 72%‐97% (26/29) with Gastrus®. Compliance was excellent and side effects mild with both regimens. Conclusions B.i.d. bismuth quadruple therapy was highly effective for H pylori eradication in treatment of naïve patients in Sardinia. Replacement of bismuth with Gastrus® might be considered when bismuth is contraindicated or unavailable.

Background: Probiotic supplementation to antibiotic regimens against Helicobacter pylori infection has been proposed to improve eradication rate and to decrease detrimental effects on gut microbiota. Aims: To evaluate microbiota modifications due to a low-dose quadruple therapy with bismuth or Lactobacillus reuteri. Methods: Forty-six patients infected with H. pylori were prospectively enrolled in a single-centre, randomized controlled trial to receive b.i.d. with meals for 10 days low-dose quadruple therapy consisting of rabeprazole 20 mg and bismuth (two capsules of Pylera® plus 250 mg each of tetracycline and metronidazole), or the same dose of rabeprazole and antibiotics plus Gastrus® (L. reuteri), one tablet twice-a-day for 27 days. Stool samples were collected at the enrolment, at the end and 30–40 days after the treatment. Gut microbiota composition was investigated with 16S rRNA gene sequencing. Results: Eradication rate was by ITT 78% in both groups, and by PP analysis 85.7% and 95.5% for Gastrus® and bismuth group, respectively. Alpha and beta diversity decreased at the end of treatment and was associated with a reduction of bacterial genera beneficial for gut homeostasis, which was rescued 30–40 days later in both groups, suggesting a similar impact of the two regimens in challenging bacterial community complexity. Conclusions: Low-dose bismuth quadruple therapy proved to be effective with lower costs and amount of antibiotics and bismuth. Gastrus® might be an option for patients with contraindications to bismuth. L. reuteri was unable to significantly counteract dysbiosis induced by antibiotics. How to administer probiotics to prevent gut microbiota alterations remains an open question.