Columnaris disease and its drug resistance in cultured exotic African catfish Clarias gariepinus in India

Abstract

Columnaris disease is a bacterial disease of fin fishes caused by the gram-negative bacillus bacterium Flavobacterium columnare whichinfects fish under stressful conditions and causing high mortality. In this study we have attempted to identify the possible infection of F. columnare bacterium in African catfish Clarias gariepinus cultured in ponds and tanks. The major objective of this study was to isolate and characterize F. columnare bacterium from cultured African catfish C. gariepinus and to find out the antibiotics resistance activity of this bacterium. For identifying the isolated bacterium (F. columnare) selected biochemical tests were performed and it was also compared with standard ATCC 51823 strain. Physicochemical tolerance tests revealed optimum growth at 25 (±2) oC, pH 7-10 and salinity <0.5%. It showed multiple drug resistance (MDR) against 29 out of 37 antibiotics. The investigation indicated that C. gariepinus culture ponds are loaded with variety of fish pathogenic MDR bacteria and F. columnare is one of them.