Abstract 1689 In vitro activity of antimicrobial peptide from African catfish against the Extended-Spectrum Beta-Lactamase (ESBL) producing Escherichia coli

The global surge in multi-drug resistant bacteria, including extended-spectrum β-lactamase (ESBL)-producing Escherichia coli has led to a growing need for new antibacterial compounds. Despite being promising, the potential of fish-derived antimicrobial peptides (AMPs) in combating ESBL-E. coli is largely unexplored. In this study, native peptides were extracted from the skin mucus of farmed African Catfish, Clarias gariepinus, using a combination of 10 % acetic acid solvent hydrolysis, 5 kDa ultrafiltration, and C18 hydrophobic interactions. These peptides were then sequenced using Orbitrap Fusion Lumos Tribrid Mass Spectrometry. The identified peptides were screened for potential antibacterial activity using Random Forest and AdaBoost machine learning algorithms. The most promising peptide was then chemically synthesized and evaluated for in vitro antibacterial activity against ESBL-E. coli (ATCC 35218) utilizing the spot-on-lawn and broth dilution methods. Eight short peptides were identified with 13 - 22 amino acid residues and molecular weight range of 968.42 to 2434.11 Da. Furthermore, most these peptides (5 of 8) were hydrophobic with neutral or more positive Grand average of hydropathicity (GRAVY). Peptide, NACAP-II was identified as the most promising with Predictive Positive Value (PPV) of 0.54, 22.7 mm Zone of Inhibition (ZOI) and Minimum Inhibitory concentration of 91.3 μg/mL. NACAP-II is thus a candidate antibacterial compound with enormous potential applications in the pharmaceutical industry. However, further studies are still required to optimize its upscale production and establish the safety profiles. This study was funded by the Academic Federation Innovative Developmental Award from the University of California, Davis