Biochemical and Molecular Characterization of Pseudomonas putida, P. fluorescens and P. aeruginosa Isolate from Oreochromis niloticus (TILAPIA ) and Clarias gariepinus (AFRICAN CATFISH)

Bacterial pathogens are a major cause of economic losses in aquaculture and pose serious threat to public health. This study investigates the phenotypic and the genomic characteristics of pathogenic Pseudomonas species in two finfish species, Oreochromis niloticus (Tilapia) and Clarias gariepinus (African catfish), sourced from the Galadima fish market in Kano metropolis, Nigeria. Twenty fish samples, including 10 Tilapia and 10 African catfish were randomly selected and tissue samples (liver, spleen, intestine and gills) were collected for analysis. Pseudomonas spp. were screened via culturing and isolation techniques and biochemical tests. Molecular identification was carried out based on 16S rRNA gene sequence analysis. Out of all the samples analyzed, 6 % tested positive for Pseudomonas spp., including P. putida (5 %), P. aeruginosa (1.25 %), and P. fluorescens (1.25 %). This study confirms the presence of potentially pathogenic Pseudomonas species in commercially important finfish species from the Galadima fish market in Kano, Nigeria. These findings highlight the need for regular monitoring and molecular surveillance of bacterial pathogens in aquaculture products to prevent economic losses and safeguard public health.