Interleukin‐8 gene expression and apoptosis induced by Salmonella Typhimurium in the presence of Bacillus probiotics in the epithelial cell

Abstract

Aims This study aimed to evaluate the effects of three Bacillus probiotics on Salmonella Typhimurium, and interleukin‐8 (IL‐8) gene expression in the co‐culture of the Bacillus and the pathogen in vitro. Methods and Results Bacillus subtilis, Bacillus indicus and Bacillus coagulans were initially turned to spore and heat‐inactivated forms. The cellular damages of the probiotics on the HT‐29 cells were investigated individually and in combination with S. Typhimurium using 3‐(4,5 dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) and fluorescence assays. To extract cell free supernatants (CFS) of the probiotics, they were cultured in selective media. The inhibitory activity of CFSs were then assayed against the pathogen. The gene expression of IL‐8 of the HT‐29 cells was evaluated by real‐time PCR in all the groups. The results showed that the CFSs of three probiotics could inhibit the growth of S. Typhimurium by more than 50%. Inhibitory effects of B. indicus and B. subtilis CFSs were related to the production of pepsin‐sensitive compounds, except B. coagulans in which the high inhibitory effect was due to organic acids. The spores of the three probiotics and the heat‐inactivated forms of B. subtilis and B. coagulans could reduce the cytotoxicity of S. Typhimurium. The cell viability also increased applying both forms probiotics against the pathogen. In all co‐culture groups, the IL‐8 gene expression induced by S. Typhimurium was reduced. Conclusions The three Bacillus probiotics can be considered as proper candidates for the prevention and treatment of S. Typhimurium food poisoning. Significance and Impact of the Study Applying probiotics as live bacteria is universally noted in foods. This study tried to discover the effects of Bacillus probiotics in the form of spore or even heat‐killed bacteria against S. Typhimurium and evaluate ratio of IL‐8 gene expression in cell culture. The most effective Bacillus probiotic will be recommended. This approach will help to use probiotics as nonvegetative cells in foods to fight gastrointestinal pathogens.

Probiotic Bacillus subtilis LF11 Protects Intestinal Epithelium Against Salmonella Infection

“…Additionally, B. subtilis produces a variety of digestive enzymes, antimicrobial peptides and other biological active molecules, improving the growth performance of broilers and feed efficiency when supplemented in diets ( Manhar et al., 2016 ; Ramlucken et al., 2019 ; Akhtar et al., 2021 ; Algburi et al., 2021 ; Popov et al., 2021 ). Moreover, B. subtilis is beneficial to the host health through modulation of microbiota composition and humoral immune responses ( Khan and Chousalkar, 2020 ; Kawarizadeh et al., 2021 ). Recently, several clinical and animal trials have demonstrated the protection of B. subtilis against Salmonella and other enteropathogenic bacteria in broilers through the load reduction in intestinal tracts, improvement of the growth performance, and immune responses ( Wu et al., 2018 ; Sokale et al., 2019 ; Abudabos et al., 2020 ).…”

Lactiplantibacillus plantarum 1201 Inhibits Intestinal Infection of Salmonella enterica subsp. enterica Serovar Typhimurium Strain ATCC 13311 in Mice with High-Fat Diet

“…In previous studies, probiotics have been found to have an inhibitory effect on S. Typhimurium. Bacillus probiotics can inhibit the activity of S. Typhimurium [ 30 ]. Bifidobacterium can down-regulate the gene expression of S. Typhimurium pathogenicity islands 1 and 2 [ 31 ].…”

The Game for Three: Salmonella–Host–Microbiota Interaction Models

“…Other studies have shown that heat-inactivated cell-free supernatant (CFS) of selected probiotics reduces the cytotoxicity of S. Typhimurium and inhibits its growth by approximately 50%. Moreover, the expression of the IL-8 gene initially induced by Salmonella was also reduced ( Kawarizadeh et al, 2020 ).…”