Bacterial infections can cause latent, low to high mortalities in farmed and wild fish populations, affecting aquaculture productivity and some of the bacteria can be zoonotic. This study isolated, characterized and determined potential pathogenic and zoonotic aerobic bacteria in farmed and wild Oreochromis jipe, Oreochromis niloticus, their hybrids and culture water source from Taita Taveta County. A total of 111 apparently healthy fish consisting of 67 Orechromis jipe, 34 Orechromis niloticus and 10 hybrids; and nine water samples (i.e. seven fish farms and two from Lake Jipe) were processed. Fish samples from each fish consisting of fish skin and kidney swabs; gills and intestinal tissues were aseptically collected. Conventional culture and biochemical tests were done to identify isolated bacteria. A total of 569 bacterial isolates of 17 genera; Pseudomonas, Aeromonas, Bacillus, Staphylococcus, Streptococcus, Micrococcus, Flavobacterium, Proteus, Vibrio, Klebsiella, Escherichia Coli, Serratia, Enterobacterium, Citrobacter, Photobacterium, Edewardsiella and Listeria (543 from the fish organs and 26 from water) were recovered. From these, skins had 33.4%; gills, 32.2%; intestines, 19.7%; kidney, 10.2%; and water 4.6% of the total bacterial genera isolated. Potential fish pathogens identified were Aeromonas, Pseudomonas, Flavobacterium, Enterococcus, Micrococcus, Vibrio and Citrobacter species. Possible zoonotic bacteria isolated found in this study were Aeromonas (19.3%), Streptococcus (6.67%), Flavobacterium (6.7%), Vibrio (4.3%), E. coli (3.7%), listeria and Serratia (1.7 %) species. Bacteria recovered from fish that were not found in the water were Serratia, Proteus, Klebsiella, Listeria, Flavobacterium, E. coli, and Edwardsiella species. In the sub-counties, the dominant/predominant bacteria were as follows; Mwatate had Staphylococcus (50%) and Bacillus (90%) species were most prevalent in O. jipe and O. niloticus respectively, while hybrid fish had Bacillus (60%) species. Voi sub-county had Aeromonas at (40%), Wundanyi had Staphylococcus (55%) and Taveta had both Pseudomonas (45%) and Aeromonas (100%) for O.jipe and O. niloticus respectively. This study shows that farmed and wild fish and source water sources harbor potentially pathogenic and zoonotic bacteria which may cause fish diseases and pose public health risks.
Keywords: Fish Pathogens, Zoonotic, prevalent, Aquaculture, Wild fish