Abstract:
A research was conducted on bacteria micro flora associated with fresh Tilapia fish
(Oreochromis niloticus) sold at Sokoto central market, Sokoto. Nigeria. Sections of the skin, gills
and intestine of ten randomly selected fishes were aseptically removed by means of a sterile scalpel
and pair of sterile scissors. Four (4g) each of the sections were homogenized in 6 ml of sterile
distilled water, which served as the original stock culture. A serial dilution up to 109 was carried
out, and surface plated on nutrient agar. A total of nine (9) bacterial species were isolated and
identified. Eight bacteria were identified to specie level and one to genus level. Six (6) were gram
positive namely: Bacillus megatanium, Listeria monocytogenes, Bacillus Pumilus, Bacillus alvei,
Bacillus Licheniformis and Staphylococcus saprophyticus and three gram negative bacteria namely:
Serratia mercescens, Providentia stuartii and Salmonella spp. The frequency of occurrences of the
isolated Bacteria indicated that Bacillus pumilius had the highest frequency of occurrence
(19.35%), while Salmonella spp. had the least occurrence (3.2%). The mean viable Bacterial count
from each section of the samples revealed 46.1 x107cfug-1 from the gills, 18.8 x 108cfug-1 from the
intestine and 27.3 x 108cfug-1 from the skin. The isolates were found to be of medical importance.
Keywords: Bacteria, Tilapia fish and Sokoto central market
