Probiotics protect mice against experimental infections

Area of Science:

• Microbiology
• Immunology
• Probiotics Research

Background:

• Probiotics modulate the host immune system and influence resistance to infections.
• Lactobacillus delbrueckii var. bulgaricus is a lactic acid bacterium with potential probiotic properties.
• Investigating specific probiotic strains for their efficacy against various bacterial pathogens is crucial.

Purpose of the Study:

• To evaluate the probiotic potential of the Lactobacillus delbrueckii UFV-H2b20 strain.
• To determine the protective effects of this strain against bacterial infections in experimental mouse models.
• To elucidate the mechanisms underlying the observed protective effects.

Main Methods:

• Utilized germ-free, monoassociated, and conventional mouse models.
• Administered L. delbrueckii UFV-H2b20 probiotic treatment.
• Challenged mice with Escherichia coli, Salmonella enterica serovar Typhimurium, and Listeria monocytogenes.
• Assessed infection outcomes via mortality rates, bacterial load in organs, and cytokine production.

Main Results:

• L. delbrueckii UFV-H2b20 enhanced E. coli clearance and systemic cytokine production.
• The strain conferred protection against Salmonella enterica serovar Typhimurium in both monoassociated and conventional mice.
• Monoassociated mice showed increased resistance to Listeria monocytogenes, with reduced mortality and bacterial burden.
• Infection with L. monocytogenes led to increased production of interferon-gamma, tumor necrosis factor-alpha, and nitric oxide in monoassociated mice.

Conclusions:

• Lactobacillus delbrueckii UFV-H2b20 demonstrates significant protective effects against bacterial infections in mice.
• The probiotic appears to exert its protective effects by up-regulating the production of key inflammatory cytokines.
• This strain shows promise as a functional probiotic for enhancing host defense mechanisms.