Study on effect of salinity and temperature on biofilm formation of flavobacterium columnare causing columnaris disease on striped catfish (Pangasianodon hypophthalmus)

Abstract

Bacterial isolated from striped catfish (Pangasianodon hypophthalmus) at Cantho University was identified as yellow- filamentous gliding bacteria, known as Flavobacterium columnare, which was used to investigate the effects of various sodium chloride concentrations and temperature levels on biofilm formation of this typical bacteria. The study was tested biofilm formation on microtiter plates at different salt concentrations and temperatures during 48 h. The result showed that biofilm formation of F.columnare on microtiters was significant inhibited from 3ppt. At higher salinities, biofilm formation greatly decreased. In the same trend, the higher temperature the lower biofilm formation but at 35C the formed biofilm was greatly inhibited and it was strongly produced at 25C and 28ºC. Interestingly, there are not significant difference of biofilm production between 28 and 31C (P>0.05). In conclusion, biofilm formation was inhibited at 3ppt and almost controlled at 9, 12 and 15 ppt on microtiter plate and was also greatly inhibited at 35C.