The present study focused on probiotic characterization and safety evaluation of Enterococcus isolates from different artisanal dairy products. All the isolates exhibited inhibitory activity against several food spoilage bacteria and food-borne pathogens, including Shigella flexneri, Staphylococcus aureus, Listeria monocytogenes, Yersinia enterocolitica, Klebsiella pneumoniae, Escherichia coli, and Bacillus subtilis. The PCR results indicated the presence of at least one enterocin structural gene in all the tested strains. The Enterococcus isolates were further evaluated regarding their safety properties and functional features. The isolates were susceptible to vancomycin, gentamycin, and chloramphenicol. The results of PCR amplification revealed that all the tested isolates harbored none of the tested virulence genes except E. faecalis (ES9), which showed the presence of esp gene. The Enterococcus isolates showed cholesterol lowering properties. The selected isolates showed a high tolerance to low pH, and toward bile salts. They also demonstrated hydrophobicity activity, auto-aggregation, and adhesion ability to the human intestinal Caco-2 cell line. These properties may contribute the bacteria colonizing the gut. This study revealed that the Enterococcus isolates, especially E. durans ES11, ES20 and ES32, might be excellent candidates for production of functional foods to promote health benefits.

Aim: To evaluate the effect of intraperitoneal injections of heat-killed Lactobacillus crispatus on breast tumor size and overall survival of Balb/c mouse received 4T1 mammary carcinoma. Materials and methods: Different doses of L. crispatus have been injected intraperitoneally in BALB/c mice. Results: Tumor size was decreased in the experiment group treated with 1 × 108 bacteria/200 μl. Treatment with 1 × 108 bacteria/200 μl resulted in survival improvement. The myeloid-derived suppressor cells and reactive oxygen species production have been increased in all groups. Cox2 expression decreased in tumor tissues of the mice treated with 108 bacteria/200 μl. The expressions of Arginase and iNos increased in the spleen and tumor tissues of those treated with 5 × 108 bacteria/200 μl. Conclusion: We have shown the protective effect of L. crispatus on survival of tumor-bearing mice.

Imposition of encapsulated non-indigenous probiotics into intestine may disturb human core microbiome