Efficacy of Potentially Probiotic Fruit-Derived Lactobacillus fermentum, L. paracasei and L. plantarum to Remove Aflatoxin M1 In Vitro

[Preparation of Lactobacillus paracei TK1501 postbiotic and its inhibitory effect against Helicobacter pylori infection in mice]

OBJECTIVE

To prepare a postbiotic using soybean fermentation product of Lactobacillus paracasei TK1501 and evaluate its inhibitory effect against Helicobacter pylori (Hp) infection in mice.

METHODS

L. paracasei TK1501 was cultured for 32 h at 37 ℃ in an anaerobic condition for solid substrate fermentation with a solid to water ratio of 1:1.5 in the substrate and an inoculation density of 5×107 CFU/mL. The postbiotic was isolated and purified using macroporous resin XAD-16N adsorption, cation exchange chromatography and HPLC, and its stability and antibacterial activity were assessed. The inhibitory effect of this postbiotic against Hp infection was evaluated in a mouse model with gastric mucosal Hp infection, which were treated with the postbiotic via gavage for 4 weeks at the dose of 0.02 or 0.1 mL. Serum levels of TNF-α and IL-1β of the mice were analyzed after the treatments, and gastric tissues of the mice were collected for HE staining.

RESULTS

L. paracasei TK1501 postbiotic could be easily degraded by protease and had good thermal stability and tolerance to exposures to acid, base, and organic solvents. In the in vitro experiment, the postbiotic showed strong inhibitory effects in bacterial cultures of Staphylococcus aureus, Hp and other common pathogenic bacteria without obviously affecting the resident bacteria in the digestive tract. In the mouse models, treatment with the postbiotic at the dose of 0.1 mL significantly alleviated Hp infection and lowered the serum levels of TNF-α and IL-1β of the mice.

CONCLUSION

L. paracasei TK1501 postbiotic has strong inhibitory effects on Hp and Staphylococcus aureus but not on normal intestinal flora in mice.

The Role of Probiotics in Improving Food Safety: Inactivation of Pathogens and Biological Toxins

Currently, many advances have been made in avoiding food contamination by numerous pathogenic and toxigenic microorganisms. Many studies have shown that different probiotics, in addition to having beneficial effects on the host's health, have a very good ability to eliminate and neutralize pathogens and their toxins in foods which leads to enhanced food safety. The present review purposes to comprehensively discuss the role of probiotics in improving food safety by inactivating pathogens (bacterial, fungal, viral, and parasite agents) and neutralizing their toxins in food products. Some recent examples in terms of the anti-microbial activities of probiotics in the body after consuming contaminated food have also been mentioned. This review shows that different probiotics have the potential to inactivate pathogens and neutralize and detoxify various biological agents in foods, as well as in the host body after consumption.

Lactiplantibacillus plantarum from Unexplored Tunisian Ecological Niches: Antimicrobial Potential, Probiotic and Food Applications

The continued exploration of the diversity of lactic acid bacteria in little-studied ecological niches represents a fundamental activity to understand the diffusion and biotechnological significance of this heterogeneous class of prokaryotes. In this study, Lactiplantibacillus plantarum (Lpb. plantarum) strains were isolated from Tunisian vegetable sources, including fermented olive and fermented pepper, and from dead locust intestines, which were subsequently evaluated for their antimicrobial activity against foodborne pathogenic bacteria, including Escherichia coli O157:H7 CECT 4267 and Listeria monocytogenes CECT 4031, as well as against some fungi, including Penicillium expansum, Aspergilus niger, and Botrytis cinerea. In addition, their resistance to oro-gastro-intestinal transit, aggregation capabilities, biofilm production capacity, adhesion to human enterocyte-like cells, and cytotoxicity to colorectal adenocarcinoma cell line were determined. Further, adhesion to tomatoes and the biocontrol potential of this model food matrix were analyzed. It was found that all the strains were able to inhibit the indicator growth, mostly through organic acid production. Furthermore, these strains showed promising probiotic traits, including in vitro tolerance to oro-gastrointestinal conditions, and adhesion to abiotic surfaces and Caco-2 cells. Moreover, all tested Lpb. plantarum strains were able to adhere to tomatoes with similar rates (4.0-6.0 LogCFU/g tomato). The co-culture of LAB strains with pathogens on tomatoes showed that Lpb. plantarum could be a good candidate to control pathogen growth. Nonetheless, further studies are needed to guarantee their use as probiotic strains for biocontrol on food matrices.

Effects of non-viable Lactobacillus reuteri combining with 14-day standard triple therapy on Helicobacter pylori eradication: A randomized double-blind placebo-controlled trial

BACKGROUND

Viable probiotics have shown effects on the eradication of Helicobacter pylori, but the role of non-viable probiotics in H. pylori eradication is unclear. This study aimed to evaluate the effects of non-viable Lactobacillus reuteri DSM17648 combining with 14-day standard triple therapy on H. pylori eradication.

MATERIALS AND METHODS

Two hundred treatment-naive H. pylori-positive adult patients were randomized equally to receive non-viable L. reuteri DSM17648 (LR group) or placebo for 4 weeks, with the latter 2 weeks treated together with triple therapy. The Gastrointestinal Symptom Rating Scale (GSRS) was completed before and after treatment. Stool samples were collected for 16S rRNA gene sequencing at week0, week2, and week8.

RESULTS

Eradication rates in the LR group and the placebo group were 81.8% and 83.7% in ITT analysis (p = 0.730), 86.2% and 87.2% in PP analysis (p = 0.830), respectively. After treatment, the mean GSRS score decreased significantly in the LR group as compared with the placebo group (1.9 ± 0.2 vs. 2.7 ± 0.3; p = 0.030). Significantly less patients in the LR group as compared with the placebo group reported abdominal distention (5.1% vs. 16.3%; p = 0.010) and diarrhea (11.1% vs. 23.5%; p = 0.022). The relative abundance of Proteobacteria phylum and Escherichia-Shigella genus in the placebo group was about 4.0-fold and 8.1-fold of that in the LR group at wk2, respectively. Significant changes of diversity and enhancements of Fusicatenibacter, Subdoligranulum, and Faecalibacterium were observed in the LR group compared with the placebo group.

CONCLUSIONS

Supplementation of non-viable L. reuteri DSM17648 with triple therapy did not improve the eradication rate of H. pylori, but it helped to build up a beneficial microbial profile and reduced the frequencies of abdominal distention, diarrhea, and the GSRS score.