Abstract
Pathogenic bacteria that are part of the natural microflora can be found in aquaculture products. Microbial pathogens associated with fish can be transmitted to humans who consume or handle the fish. This study aimed to isolate human pathogenic bacteria present in the gills, intestine and skin of apparently healthy and spoil fishes. Tilapia (Oreochromisniloticus) and Cat fish (Clariaslazera) were collected from Wukari old market and Yam market of Wukari Nigeria. Bacteria were isolated from the fish gill, intestine and skin. The growth properties of distinct isolates on specific culture media were used to differentiate and characterize them. Pathogenic bacteria were recovered from various fish species that appeared with different features. The following human pathogenic bacteria were isolated; Escherichia coli and Staphylococcus aureus. The total bacteria count value ranges between 0.12 x 105 to 3.52 x 105 for the tilapia fish and 0.12 x 105 to 3.96 x 105 cfu/ml for cat fish. The identification revealed that Staphylococcus aureus and Escherichia coli was the most abundant pathogenic bacteria and also present in the initial water samples collected. Presence of Staphylococcus aureus and Eshcherichia coli is attributed to contamination of the fish samples by man through handling and processing. These enteric bacteria in fish serve as indicator organisms of faecal contamination and or water pollution. Their presence also represents a potential hazard to humans’ life. The isolates were higher from Yam market samples compared to Wukari old market.

Key words: Isolation, Pathogenic bacteria, fresh fish, Escherichia coli, Staphylococcus aureus, Wukari.