ISOLATION AND IDENTIFICATION OF BACTERIAL PATHOGEN FROM TILAPIA FISH AND THEIR ANTIBIOGRAM STUDY

Abstract

This study was conducted on isolation and identification of bacterial pathogens from Tilapia fish (Oreochromis niloticus) that collected from local market of the Dinajpur city, Bangladesh and their antibiogram study. Sections of the skin, gills and intestine of twenty randomly selected fishes were aseptically removed by means of a sterile scalpel and pair of sterile scissors. A serial dilution was prepared and from last dilution 0.1ml was plated on nutrient agar plates. The purified isolates were identified according to Gram staining reaction, cell morphology, cultural characteristics, and biochemical characteristics. The sensitivity of bacteria isolated from Tilapia fishes to the following antibiotics Amoxicilin, Cefixime, Azithromicin, Chloramphenicol, Ciprofloxacin, Penicillin G, Erythromicin, Vancomycin, Gentamycin and Neomycin was performed. Total four different species of bacteria were isolated and identified. Gram negative include Pseudomonas spp. Salmonella spp. and Escherichia coli, while gram positive species include Staphylococcus spp. Some of these pathogens have tendancy to transmit to man (who eat fish meat or deal with fish and fish products). All collected samples showed bacterial growth and yielded 77 isolates. The isolated bacteria were 13(16.88%) Pseudomonas spp, 31 (40.26%) Escherichia coli, 10 (12.99%) Salmonella spp. and 23 (29.87%) Staphylococcus spp. The frequency of occurrences of the isolated Bacteria indicated that had the highest frequency of occurrence Escherichia coli (40.26), while Salmonella spp. had the least occurrence (12.99%). The result of sensitivity test was variable. Most species of bacteria isolated were sensitive to gentamycin, chloramphenicol, ciprofloxacin and Azithromycin but resistant to Amoxicilin, Penicilin G, Vancomycin and Erythromycin. The isolates were found to be of medical importance. Hence it is considered that a variety of bacterial species can be associated with fresh Tilapia fish related pathogen to humans