The Bacterial Flora Of Tilapia (Oleochromis Niloticus) And Catfish (Clarias Gariepinus) From Earthen Ponds In Sagana Fish Farm And Masinga Dam

ABSTRACT

Fish is a worldwide distributed food commodity regarded a cheap source of protein especially in the developing countries like Kenya. It provides a good balance of protein, vitamins and minerals. However, bacteria occur naturally on the skin, in the gut and in the slime of living fish, even though they do no harm to the, the microorganisms may cause harm to consumers. Also, some of the microorganisms associated with fish may carry genes of antibiotic resistance that can be passed to pathogens of clinical importance. Food borne diseases traced to fish consumption have been reported world over including Kenya. In Kenya though aquaculture has been promoted, the aspect of food quality as far as consumption of fish is concerned is underestimated. Sagana fish farm and Masinga dam provide fish for Kenyan markets including Nairobi. No information available when this study was conducted on quality of fish from Sagana fish farm and Masinga dam. The study was designed to determine the bacterial flora of Tilapia and Catfish from earthen ponds at Sagana fish farm and Masinga dam and to determine the anti- microbial response of the pathogenic bacteria. Samples of Tilapia fish and Catfish were collected from Sagana farm and Masinga dam in dry and rainy season. The fish were skinned and gut content taken for laboratory test. Samples of water and water sediments from the two study sites were also collected. The samples were processed and cultured in MacConkey agar and the colonies sub cultured in selective media. The colonies were subjected to morphological examination from cultures and biochemical test carried out using commercially available API kits. The results obtained from this study showed the presence of bacterial species belonging to Enterobacter spp. (n=34), Aeromonas spp. (n=5), Vibrio spp. (n=3), Pseudomonas spp. (n=6) and Acinetobacter spp. (n=2) were isolated during the dry season while bacterial species belonging to Enterobacter spp. (n=31), Aeromonas spp. (n=4), Pseudomonas spp. (n=6) were isolated during the dry season. Antimicrobial susceptibility showed that the highest rates of resistance was found against Amoxicillin (Aml) (65.9% of isolates), Ampicillin (Amp) (61.5% of isolates), Tetracycline (Te) (31.8% of isolates), and Chlorampenicol (C) (27.5 % of isolates) while the lowest was Nalidixic acid (Na), Streptomycin (S) and Cefuroxine (Cxm) at (4.4% of isolates) each. All isolates were sensitive to Ciprofloxacin (Cip), Gentamycin (Gen) and Cefotaxine (CTX). The presence of the above organisms some of which are potentially pathogenic to humans is an indication that fish improperly handled, undercooked or consumed raw may cause disease to susceptible individuals while the antimicrobial resistance by some of the isolates is an indication that the use of antibiotics in aquaculture for promotion of growth should be studied further with view to policy formulation.