Metagenomic Changes of Gut Microbiota following Treatment of Infection with a Simplified Low-Dose Quadruple Therapy with Bismuth or .

BACKGROUND

Probiotic supplementation to antibiotic regimens against 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 .

METHODS

Forty-six patients infected with 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 (), 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. was unable to significantly counteract dysbiosis induced by antibiotics. How to administer probiotics to prevent gut microbiota alterations remains an open question.