Limosilactobacillus fermentum LF61: A multidimensional study on safety and functionality from genomics to clinical...

Area of Science:

• Microbiology
• Immunology
• Gastroenterology

Background:

• Limosilactobacillus fermentum LF61 is a human milk-derived strain.
• Probiotics modulate the gut microbiome and immune system.
• Understanding LF61's safety and efficacy is crucial for its application.

Purpose of the Study:

• To comprehensively assess the safety and functional efficacy of Limosilactobacillus fermentum LF61.
• To investigate LF61's impact on the gut microbiome and host immune response.
• To provide evidence for LF61 as an immunomodulatory probiotic.

Main Methods:

• Genomic analysis for virulence and resistance genes.
• In vitro survival assays (gastric/intestinal conditions) and cytotoxicity tests.
• Acute oral toxicity study in mice (LD50 determination).
• Randomized, double-blind clinical trial assessing immune markers (LL-37, IgA, IgG, IgM).
• Metagenomic analysis of gut microbiome composition and function.

Main Results:

• LF61 genome lacks virulence factors and antibiotic resistance genes, meeting safety criteria.
• High in vitro survival rates in simulated gastrointestinal conditions and non-toxic to Caco-2 cells.
• Acute oral toxicity LD50 > 2 × 10^10 CFU/kg in mice.
• Clinical trial showed increased serum LL-37 (12.3%) and immunoglobulins (IgA, IgG, IgM).
• LF61 promoted beneficial bacteria, activated carbohydrate metabolism, and maintained microbiome diversity.

Conclusions:

• Limosilactobacillus fermentum LF61 is a safe and functionally effective probiotic.
• LF61 modulates the gut-immune axis through bidirectional regulatory mechanisms.
• LF61 demonstrates potential as a novel immunomodulatory probiotic for gut health.