Abstract

Searching for alternative possible treatments against H. pylori infections, the Laboratory of Bacterial Pathogenicity (University of Concepción, Chile) characterized strains isolated from stomach, including Lactobacillus fermentum UCO-979C whose probiotic properties and anti-Helicobacter pylori activity are remarkable. Since some Lactobacillus strains have the ability to form, in vitro and in vivo, biofilms and bacteria change their phenotype when forming biofilms, it was necessary to study the capacity of L. fermentum UCO-979C to form biofilms on abiotic surfaces and on cellular models (gastric adenocarcinoma AGS cells and colorectal carcinoma Caco-2 cells) and its antagonistic effect against an ATCC H. pylori pathogenic strain. The ability of L. fermentum UCO-979C to form biofilms on different abiotic surfaces was determined using various inoculums, media (MRS, BHI and DMEM) and culture times and assessed by the crystal violet method. Biofilm formation on cellular models was studied using different inoculums and assessed by scanning electron microscopy. To determine the anti-H. pylori colonization activity of L. fermentum UCO-979C on the cellular models, the urease test and fluorescence microscopy using FITC were used. L. fermentum UCO-979C formed biofilms on abiotic and biotic surfaces and variables favoring thicker biofilms were determined. This strain also showed up to 83.1% inhibition of H. pylori colonization on the cellular models.