Bacterial load in twelve freshwater fishes of four feeding habits in Bangladesh

Abstract

Homogenized samples of skin, gill and gut of twelve freshwater fishes of four feeding habits were used for bacteriological test. Total bacterial count (TBC), total coliform (TC), faecal coliform (FC), faecal streptococci (FS) and total Vibrio?like colonies were enumerated using serial dilution and spread plate techniques. Variation of bacterial loads among the fishes of various feeding habits was insignificant. The TBC, TC, FC, FS and total Vibrio counts ranged from 1.72 ± 0.68 × 10⁸ to 7.00 ± 3.39 × 10⁸, 2.49 ± 1.72 × 10⁶ to 6.55 ± 3.00 × 10⁶, 1.58 ± 1.29 × 10⁶ to 2.76 ± 1.42 × 10⁶, 4.83 ± 2.09 × 10⁴ to 1.19 ± 0.46 × 10⁵ and 2.06 ± 0.67 × 10³ to 3.68 ± 2.02 × 10⁵, respectively among various feeding groups. However, gill and gut had significantly higher density of TBC, TC and FC than that of the skin. High counts of indicator organisms indicate that market fishes of all varieties could be the potential reservoirs in transmission of pathogenic bacteria responsible for diarrhoeal disease.