Engineered Probiotic Bacteria Expressing Antimicrobial Peptide Fight E. coli Gut Infections in Mice | Research

The takeaway

Freeze-dried engineered L. lactis expressing AMP HI reduced ETEC gut colonization, restored intestinal barrier, and suppressed inflammation in mice, demonstrating translational potential for engineered probiotic AMPs.

Living antibiotic factory
Engineered probiotic bacteria produce antimicrobial peptide directly in the gut, fighting infection where antibiotics often fail to reach

What the researchers found

L. lactis/HI: optimized freeze-drying (6% sorbitol), reduced ETEC colonization and LPS, restored tight junction genes, downregulated TNF-α/IL-1β/IL-6, upregulated IL-10 in ETEC-infected mouse intestine.

Why it matters

Oral AMP delivery via engineered probiotics solves the stability/delivery problem — the probiotic produces the antibiotic exactly where the infection is.

How the study worked

Engineering of L. lactis to express AMP HI, freeze-drying optimization with cryoprotectants, oral administration in ETEC-infected BALB/c mice, with colonization, LPS, tight junction, and cytokine assessment.

What this study cannot tell us

Mouse model. ETEC is one pathogen; activity against others not tested. Regulatory pathway for engineered probiotics complex.

How to read the evidence

Preclinical proof-of-concept with translational freeze-drying optimization. Novel engineered probiotic AMP approach.

When this study was published

Published in 2025.

The bigger picture

Engineered probiotics delivering AMPs could become a new class of oral anti-infectives that work locally in the gut without systemic side effects.

Questions still open

Could engineered probiotic AMPs replace oral antibiotics for gut infections?
How long does AMP expression persist after oral probiotic dosing?
Would this approach work against C. difficile infection?

Common questions

What is an engineered probiotic AMP?

A beneficial gut bacterium (L. lactis) genetically modified to produce antimicrobial peptides. When swallowed, it colonizes the gut and produces antibiotics exactly where infection occurs.

Is this better than regular antibiotics?

Potentially for gut infections. Regular antibiotics destroy beneficial bacteria system-wide. Engineered probiotics produce AMPs locally in the gut while maintaining the beneficial microbiome.

Read the original research

Engineered Lactococcus lactis expressing antimicrobial peptide HI: Enhanced survival and protection against ETEC in mice.

Journal of biotechnology, 410, 331-340

View on PubMed ↗Publisher’s paper ↗

Citation

Hu, Mingyang; Bi, Chongpeng; Li, Yuwen; Xue, Yutong; Cha, Sina; Zhao, Lu; Xue, Chenyu; Dong, Na. (2026). Engineered Lactococcus lactis expressing antimicrobial peptide HI: Enhanced survival and protection against ETEC in mice.. Journal of biotechnology, 410, 331-340. https://doi.org/10.1016/j.jbiotec.2025.12.019