A Snake Venom-Derived Antimicrobial Peptide Destroys Drug-Resistant Bacterial Biofilms on Medical Instruments

Cath-A inhibited growth of A. baumannii clinical isolates from medical instruments at MIC values of 8-16 μg/mL. Against P. aeruginosa, MICs ranged from 16 to ≥256 μg/mL. The peptide significantly removed established biofilms of both species. Cath-A showed minimal hemolytic and cytotoxic activity against eukaryotic cells. Recombinant production in E. coli BL21 using pET-32a(+) vector with thioredoxin fusion yielded 17.6 mg/L of partially purified peptide with confirmed antimicrobial activity after enterokinase cleavage.

Researchers designed Cath-A, a 34-amino-acid derivative of cathelicidin-BF from snake venom. Antimicrobial activity was tested against A. baumannii and P. aeruginosa isolates from hospital medical instruments using standard MIC determination. Biofilm disruption was assessed on established biofilms. For production, the Cath-A gene was cloned into pET-32a(+) and expressed as a thioredoxin fusion protein in E. coli BL21. Purification used Ni2+ affinity chromatography followed by enterokinase cleavage to release the mature peptide.

Hospital-acquired infections from drug-resistant bacteria like A. baumannii kill thousands of patients annually, and biofilm formation on medical devices makes these infections nearly impossible to treat with conventional antibiotics. Antimicrobial peptides represent a fundamentally different mechanism of killing bacteria that is harder for pathogens to develop resistance against, making Cath-A and similar peptides promising alternatives.

Antimicrobial resistance is a global health crisis, and the pipeline of new conventional antibiotics has slowed dramatically. Antimicrobial peptides from animal venoms represent an untapped reservoir of novel anti-infective agents. This study advances the field by both identifying an effective peptide and demonstrating a scalable production method — addressing the two key barriers (efficacy and manufacturing) that have limited AMP clinical development.

All testing was in vitro — no animal infection models were used. The P. aeruginosa MICs were highly variable (16 to ≥256 μg/mL), suggesting inconsistent activity against this pathogen. The peptide was only partially purified, and the 17.6 mg/L yield may need significant optimization for commercial production. Stability in biological fluids, pharmacokinetics, and in vivo toxicity were not assessed. The specific biofilm disruption mechanism was not elucidated.