IDENTIFICATION, CHARACTERIZATION AND DETERMINATION OF MULTIPLE ANTIBIOTIC RESISTANCE (MAR) BACTERIA IN NILE TILAPIA (O. NILOTICUS)G.Y. LIYANAGE, MANAGE S. AND PATHMALAL M. MANAGE
Concurrent resistance to antibiotics of different structural classes has arisen in a multitude of bacterial species which causes complicating the therapeutic management for both human and animal pathogenic diseases. The objectives of the study were to isolate and characterize antibiotic resistant bacteria from Nile Tialapia (O. niloticus) and to determine Multiple Antibiotic Resistance (MAR) index of against; Tetracycline (TET), Ampicillin (AMP), Amoxicillin (AM.X), Sulfamethaxasol (SMX), Erythromycin (ERM), Cloxacillin (CLOX), Azythromycin (AZY) and Ciprofloxacin (CIP). The total of 165 antibiotic resistance bacteria strains from the intestine (75) and the gills (90) of Nile Tialapia was isolated. The highest antibiotic resistance of the bacteria was found against TET (44%) where the least resistance was recorded against CIP (2%), CLOX (1%), and AZY (1%) respectively. The Bacillus sp. was the dominant intestinal bacteria representing 40% and E. coli (20%) were recorded as the dominant and co-dominant bacteria in the gills. More than 50% of bacteria isolates exceeded the 420 ppm of MIC of the tested antibiotics except CIP, CLOX and AZY. The calculated MAR index ranged from 0.11 â 0.58, suggesting that the Nile Tilapia (O. niloticus) plays as a reservoir for antibiotic-resistant bacteria and may create health risk in human.