Comparative Evaluation of the Antimicrobial and Mucus Induction Properties of Selected Bacillus Strains against Enterotoxigenic Escherichia coli.

Natalia Bravo Santano,Michal Letek,Tomasz Maciej Cieplak,Erik Juncker Boll,Enver Keleszade,Adele Costabile,Lena Catrine Capern

doi:10.3390/antibiotics9120849

Abstract

Probiotics have been shown to bind to host receptors, which are important for pathogen adhesion and induce the host’s production of defence factors. They can activate the goblet-cell-derived production of mucins, a major component of the mucus layer and a physical barrier participating in limiting the proximity of microorganisms to the epithelial layer. In the last decade, Bacillus spp. strains have gained interest in human and animal health due to their tolerance and stability under gastrointestinal tract conditions. Moreover, Bacillus spp. strains can also produce various antimicrobial peptides that can support their use as commercial probiotic supplements and functional foods. The present study aimed to evaluate and determine the ability of selected Bacillus spp. strains to inhibit the growth of enterotoxigenic Escherichia coli (ETEC) F4 and to reduce binding of ETEC F4 to HT29-16E (mucus-secreting and goblet-like) human intestinal cells. Moreover, mucus production in the HT29 cells in the presence of the Bacillus spp. strains was quantified by ELISA. Bacillus spp. strains (CHCC 15076, CHCC 15516, CHCC 15541, and CHCC 16872) significantly inhibited the growth of ETEC F4. Moreover, the ability of the probiotic Bacillus spp. strains to stimulate mucin release was highly strain dependent. The treatment with Bacillus subtilis CHCC 15541 resulted in a significant increase of both MUC2 and MUC3 in HT29-16E cells. Therefore, this strain could be an up-and-coming candidate for developing commercial probiotic supplements to prevent infections caused by ETEC F4 and, potentially, other pathogens.

Highlights

Gastrointestinal infections are typically treated with antibiotics
We first screened for the direct antimicrobial activity of our collection of seven Bacillus spp
Bacillus Subtilis and Bacillus Amyloliquefaciens Strains Reduce the Growth of Pathogenic enterotoxigenic Escherichia coli (ETEC) F4 this end, we employed an agar well diffusion-based method to assess the inhibitory effect of the probiotic strains againstfor an enteric pathogen: Enterotoxigenic

Summary

Introduction

Owing to the increased antimicrobial resistance in recent years and their unfavourable effects on host-microbiota and health, new alternatives have been considered Due to their characteristics, probiotics are good candidates for preventing and treating gastrointestinal infections and acute diarrhea [1]. Much interest and value have been placed on non-sporulated bacteria such as lactobacilli and bifidobacteria as alternatives to antibiotics and as cost-effective treatments for both animal and human gut infections [2]. It is well-known that probiotics may exert direct antagonism by producing antimicrobial compounds, co-aggregating with pathogens, or downregulating their virulent. Through their immune-modulatory actions, probiotics can help prevent or clear the infection more effectively, for example, by inducing the secretion of specific interleukins or promoting the maturation of dendritic cells [4]

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