Every Peptide

Peptide field guide

Lachnospirin-1

A novel antimicrobial peptide reported in 2026 to have activity against carbapenem-resistant Acinetobacter baumannii in vitro and in mouse infection models.

Evidence: emerging Safety: unknown Status: research Updated: March 21, 2026 AntimicrobialInfectious disease

What it is

Lachnospirin-1 is described by the authors as a novel antimicrobial peptide that they screened and synthesized as a potential lead against drug-resistant Acinetobacter baumannii.

Why people care

Carbapenem-resistant A. baumannii (CRAB) is a high-priority hospital pathogen. New antibiotic classes are scarce, and treatment can be extremely limited.

Antimicrobial peptides are attractive because they can act quickly (often via membrane-active mechanisms) and may not follow the same resistance patterns as small-molecule antibiotics. But translation is difficult: stability, toxicity margins, delivery, and manufacturing all matter.

How it might work

Reported mechanisms include a multi-pronged profile:

  • disruption of bacterial membranes
  • interaction with / neutralization of lipopolysaccharide (LPS)
  • induction of oxidative stress

These are mechanistic clues, not proof of clinical utility.

Evidence landscape

As of March 2026, the evidence we’ve indexed is preclinical, including:

  • bactericidal activity against CRAB in vitro
  • reported activity against biofilms and persister cells
  • reported efficacy and tolerability signals in mouse models

Key upgrades in confidence would include:

  • potency and spectrum data across many clinical isolates
  • pharmacokinetics and serum stability
  • rigorous toxicity packages at effective exposures
  • resistance development studies

Latest updates

  • 2026-03-21: A Virulence paper reports lachnospirin-1 activity against CRAB, including biofilm and persister effects, plus mouse model efficacy.

Safety reality

“Favorable safety profile” claims in early papers often reflect limited assays and short observation windows. The clinical safety bar for a systemic antimicrobial is high, and peptide-specific issues (hemolysis, nephrotoxicity, immunogenicity) are common failure points.

References

  • She P, et al. Antibacterial efficacy and mechanism of the novel antimicrobial peptide lachnospirin-1 against Acinetobacter baumannii. Virulence. (2026).