Probiotic Fermented Milk Boosts Defensin Production to Protect Against Typhoid in Mice | Research

The takeaway

Lacticaseibacillus rhamnosus D1 fermented milk protected mice from typhoid fever by upregulating antimicrobial peptide (defensin) production in the gut.

Probiotics boost defensins
Fermented milk with L. rhamnosus D1 increased the gut's own antimicrobial peptide production to fight typhoid

What the researchers found

L. rhamnosus D1 fermented milk upregulated gut defensin production, protecting mice from Salmonella typhi infection through enhanced innate antimicrobial peptide defense.

Why it matters

Boosting the body's own antimicrobial peptides through simple dietary interventions like fermented milk could provide low-cost, accessible infection prevention, especially in developing countries where typhoid is endemic.

The numbers in context

BALB/c mice were used. Multiple outcomes measured: survival rates, weight changes, bacterial translocation levels, antimicrobial peptide and cytokine mRNA expression, and microbiota composition.

How the study worked

Mouse typhoid model treated with L. rhamnosus D1 fermented milk. Assessed defensin expression, bacterial burden, gut barrier function, and immune markers.

Who was studied

BALB/c mice challenged with Salmonella Typhimurium

What this study cannot tell us

Mouse study. Human gut defensin responses to probiotics may differ. Typhoid pathogenesis differs between mice and humans. Specific probiotic strain may not be commercially available.

How to read the evidence

Preliminary evidence: mouse infection model showing probiotic-mediated defensin upregulation. No human typhoid prevention data.

When this study was published

Published in 2025. Links probiotic science to antimicrobial peptide innate defense.

The bigger picture

This connects probiotics to antimicrobial peptide biology. Rather than providing direct antimicrobial effects, probiotics may protect against infections by training the host's innate defense system to produce more defensins — a natural, self-sustaining antimicrobial strategy.

Questions still open

Would L. rhamnosus D1 fermented milk reduce typhoid risk in endemic areas?
Can other probiotic strains also upregulate defensin production?
Could defensin-boosting probiotics protect against antibiotic-resistant infections?

Common questions

Can yogurt protect against infections?

This study shows fermented milk with specific probiotics can boost your gut's natural antimicrobial peptides (defensins), which help fight bacterial infections. While not a replacement for vaccines or antibiotics, probiotic fermented foods may enhance your innate immune defense.

What are defensins?

Defensins are natural antimicrobial peptides produced by cells lining your gut, skin, and airways. They kill bacteria by punching holes in their membranes. Probiotics can stimulate your body to produce more of these protective peptides.

Read the original research

Lacticaseibacillus rhamnosus D1 Fermented Milk Confers Protection Against Typhoid Fever Through Immunomodulation and Gut Microbiota Regulation in Mice.

Microorganisms, 13(10)

View on PubMed ↗Publisher’s paper ↗

Citation

Acurcio, Leonardo; Sandes, Sávio; Rios, Diego; Sant'Anna, Felipe; Pedroso, Silvia; Bastos, Rafael; Souza, Marcelo; Nicoli, Jacques. (2025). Lacticaseibacillus rhamnosus D1 Fermented Milk Confers Protection Against Typhoid Fever Through Immunomodulation and Gut Microbiota Regulation in Mice.. Microorganisms, 13(10). https://doi.org/10.3390/microorganisms13102348