Nisin

also known as: Nisin A, Nisaplin

The food-grade antimicrobial peptide — a 34-amino-acid lantibiotic used in food preservation worldwide for 50+ years, with emerging pharmaceutical applications against MRSA and biofilms.

A 34-amino-acid polycyclic antimicrobial peptide produced by Lactococcus lactis, containing unusual lanthionine and methyl-lanthionine bridges, with a dual mechanism of lipid II binding and pore formation.

Mechanism of action

Dual mechanism: (1) Binds lipid II (the same peptidoglycan precursor target as vancomycin) with high affinity, sequestering it and blocking cell wall synthesis; (2) Uses the lipid II-nisin complex to form pores (2–2.5 nm diameter) in the bacterial membrane, causing rapid ion efflux and cell death. This dual action makes resistance development difficult. Active against gram-positive bacteria; gram-negatives are protected by the outer membrane.

Primary uses

Food preservation (dairy, meat, beverages)
Anti-MRSA research
Anti-biofilm strategies
Mastitis treatment research (veterinary)

Typical dosing

2.5–25 mg/kg (food applications) added during food processing (food additive)

Food use: typically 1–25 ppm. Pharmaceutical dosing under investigation for topical and local applications.

Regulatory status

FDA GRAS (Generally Recognized as Safe) status as a food preservative (since 1988). Approved as food additive E234 in the EU. Not FDA-approved as a pharmaceutical drug, though pharmaceutical applications are in development.

References

[review] Breukink E, de Kruijff B. "Lipid II as a target for antibiotics." Nat Rev Drug Discov, 2006;5:321-332.
[review] Shin JM, et al. "Biomedical applications of nisin." J Appl Microbiol, 2016;120:1449-1465.

Related peptides

Vancomycin

The iconic glycopeptide antibiotic — the gold-standard MRSA treatment for over 60 years, acting by binding D-Ala-D-Ala to block cell wall synthesis.

Bacitracin

The topical first-aid antibiotic — one of the most widely used over-the-counter peptide antibiotics, found in virtually every household first-aid kit.

LL-37

The only human cathelicidin — an antimicrobial peptide with direct activity against bacteria, fungi, viruses, and biofilms, with additional roles in wound healing and immune signaling.

Polymyxin B

The gram-negative last resort — a cyclic lipopeptide antibiotic revived from the 1950s as a critical weapon against carbapenem-resistant Acinetobacter, Pseudomonas, and Klebsiella.

Disclaimer

This entry is for educational purposes only and does not constitute medical advice. Dosing information reflects published regulatory or research data and is not a recommendation. Many compounds described here are not approved for human use in the United States. Consult a licensed medical professional before considering any peptide therapy.