Antimicrobial Peptide Nisin targets Pseudomonas aeruginosa and mitigates the Inflammation in Zebrafish Larvae

Abstract

Pseudomonas aeruginosa is an opportunistic gram-negative bacterium known for its high virulence and antibiotic resistance, making alternative therapeutic approaches essential. Antimicrobial peptides like Nisin, a lantibiotic with bactericidal activity, have shown promising effects against various bacterial infections. This study evaluates the antimicrobial and anti-inflammatory effects of Nisin (200 μg/mL) against P. aeruginosa infection in zebrafish larvae. Larvae were exposed to P. aeruginosa (1 × 10⁶ CFU/mL) for 24 hours, followed by Nisin treatment for an additional 24 hours. Bacterial load, survival rates, and histopathological changes were assessed to determine the peptide’s therapeutic potential. Additionally, oxidative stress markers—including reactive oxygen species, nitric oxide levels, and lipid peroxidation were analyzed to assess Nisin’s anti-inflammatory effects. Apoptotic and oxidative stress responses were further investigated using acridine orange, diphenyl-1-pyrenylphosphin, and dichlorofluorescein diacetate fluorescence assays. Results demonstrated that Nisin significantly reduced bacterial load and improved survival rates, with notable suppression of ROS, NO production, and lipid peroxidation. Histopathological analysis confirmed that Nisin mitigated tissue damage and inflammatory responses, suggesting its potential as an effective antimicrobial agent against P. aeruginosa infections. This study underscores the dual role of Nisin in both bacterial clearance and inflammation reduction, supporting its use as an alternative or adjunct therapy for antibiotic-resistant bacterial infections. Further molecular studies are required to elucidate its mechanisms of action in host-pathogen interactions.