The human antimicrobial peptide LL-37 and its fragments possess both antimicrobial and antibiofilm activities against multidrug-resistant Acinetobacter baumannii.
Feng. Xiaorong X; Sambanthamoorthy. Karthik K; Palys. Thomas T; Paranavitana. Chrysanthi C
Key Findings
- LL-37 and the KS-30 fragment killed MDR A. baumannii within 30 minutes at very low concentrations (0.25‑1 µg/mL).
- All tested fragments prevented bacterial adhesion and disrupted existing biofilms at 32‑128 µg/mL.
- No detectable toxicity to human cells was observed after 24 hours at the effective concentrations.
Practical Outcomes
- These results suggest LL-37‑based peptides could become a new class of anti‑infection agents, especially for hard‑to‑treat, biofilm‑forming bacteria. For biohackers, the data highlight that peptide‑based approaches are promising but still early‑stage; safe human use would require formulation, dosing, and regulatory clearance beyond current lab findings.
Summary
The human peptide LL-37 and its shorter pieces can quickly kill drug‑resistant Acinetobacter baumannii bacteria in the lab and stop them from forming sticky biofilms, all without harming human cells at the doses that work.
Abstract
Acinetobacter baumannii infections are difficult to treat due to multidrug resistance. Biofilm formation by A. baumannii is an additional factor in its ability to resist antimicrobial therapy. The antibacterial and antibiofilm activities of the human antimicrobial peptide LL-37 and its fragments KS-30, KR-20 and KR-12 against clinical isolates of multidrug-resistant (MDR) A. baumannii were evaluated. The minimal inhibitory concentration (MIC) of LL-37 against MDR A. baumannii isolates ranged from 16 to 32 μg/mL. The MIC of KS-30 fragment varied from 8.0 to 16 μg/mL and the KR-20 fragment MIC ranged from 16 to 64 μg/mL. LL-37 and KS-30 fragment exhibited 100% bactericidal activity against five A. baumannii strains, including four MDR clinical isolates, within 30 min at concentrations of 0.25-1 μg/mL. By 0.5h, the fragments KR-20 and KR-12 eliminated all tested strains at 8 and 64 μg/mL respectively. LL-37 and its fragments displayed anti-adherence activities between 32-128 μg/mL. A minimum biofilm eradication concentration (MBEC) biofilm assay demonstrated that LL-37 inhibited and dispersed A. baumannii biofilms at 32 μg/mL respectively. Truncated fragments of LL-37 inhibited biofilms at concentrations of 64-128 μg/mL. KS-30, the truncated variant of LL-37, effectively dispersed biofilms at 64 μg/mL. At 24h, no detectable toxicity was observed at the efficacious doses when cytotoxicity assays were performed. Thus, LL-37, KS-30 and KR-20 exhibit significant antimicrobial activity against MDR A. baumannii. The prevention of biofilm formation in vitro by LL-37, KS-30 and KR-20 adds significance to their efficacy. These peptides can be potential therapeutics against MDR A. baumannii infections.
Study Information
pubmed
2013
2013-09-23T00:00:00.000Z
10.1016/j.peptides.2013.09.007
133
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