Antibacterial Efficacy of Aqueous and Ethanolic Extracts of Pear (Pyrus communis) Leaves Against Bacterial Pathogens Isolated from Infected Africa Catfish (Clarias gariepinus)

Abstract

The increasing prevalence of antibiotic-resistant pathogens in aquaculture has heightened the need for natural alternatives. This study investigates the antibacterial activity of both aqueous and ethanolic extracts of pear (Pyrus communis) leaves against bacterial isolates obtained from infected African catfish (Clarias gariepinus). Diseased fish were collected from multiple farms in Ondo State, Nigeria. Pathogens such as Aeromonas hydrophila, Streptomycetes spp., and Flavobacterium spp. were isolated from infected tissues. Aqueous and ethanolic extracts were prepared and tested using the agar well diffusion method. The ethanolic extract exhibited significantly higher antibacterial activity across all concentrations (100, 200, and 400 mg/mL), with inhibition zones ranging from 12.2 ± 0.2 mm to 24.7 ± 0.2 mm. Streptomycetes showed the highest sensitivity to both extracts, while Flavobacterium displayed the lowest. The results affirm the potential of Pyrus communis leaf extracts as effective antimicrobial agents in aquaculture and support the integration of plant-based therapies for sustainable fish health management.