Antibacterial Activity of a Probiotic and Synbiotic Suspension Combined with Inulin Against Helicobacter pylori in an In Vitro Model

Helicobacter pylori is a highly prevalent pathogen associated with chronic gastritis, peptic ulcers, and gastric cancer. Treatment is increasingly challenging due to antibiotic resistance and adverse effects that can reduce adherence. These limitations have encouraged the exploration of complementary strategies. This study evaluated the in vitro antibacterial activity of selected probiotic strains and synbiotic formulations containing inulin against clinical isolates of H. pylori. Isolates obtained from gastric biopsies were identified by MALDI-TOF. Four probiotic strains (Lacticaseibacillus casei, Lacticaseibacillus rhamnosus, Limosilactobacillus fermentum, and Streptococcus thermophilus) were tested individually and as a mixed culture, both alone and combined with inulin. Antibacterial activity was assessed using the agar well diffusion method under microaerophilic conditions after 72 h of incubation at 37 °C. Variable inhibitory effects were observed, with L. fermentum (8.08 ± 1.98 mm) and the probiotic mixture (7.92 ± 0.90 mm) showing greater activity, while S. thermophilus exhibited limited inhibition. The addition of low-dose inulin (3 mg/mL) was associated with increased inhibition by the probiotic mixture (9.58 ± 1.51 mm), whereas higher concentrations did not enhance this effect. These findings indicate that certain probiotic and synbiotic formulations exhibit in vitro activity against H. pylori and warrant further investigation as complementary approaches.