|Declercq, Annelies - Ghent University|
|Peatman, Eric - Auburn University|
|Decostere, Annemie - Ghent University|
Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/9/2017
Publication Date: 6/5/2017
Publication URL: http://handle.nal.usda.gov/10113/5832864
Citation: Lange, M.D., Farmer, B.D., Declercq, A.M., Peatman, E., Decostere, A., Beck, B.H. 2017. Sickeningly sweet: L-rhamnose stimulates Flavobacterium columnare biofilm formation and virulence. Journal of Fish Diseases. doi:10.1111/jfd.12629.
Interpretive Summary: Flavobacterium columnare is becoming the principal bacterial pathogen of different farmed fish species globally, causing immense economic losses. Previous work had sought to characterize biological processes of this bacterium as a means to understand overall pathogenesis. The current report focuses on the ability of L-rhamnose to stimulate F. columnare to form biofilms, and regulate virulence to ultimately cause significant disease in channel catfish. These studies will lead to a better understanding of F. columnare life cycle and benefit us in the development of treatments for Columnaris disease.
Technical Abstract: Flavobacterium columnare, the causative agent of columnaris disease causes substantial mortality worldwide in numerous freshwater finfish species. Due to its global significance and impact on the aquaculture industry continual efforts to better understand basic mechanisms that contribute to disease are urgently needed. The current work sought to evaluate the effect of L-rhamnose on the growth characteristics of F. columnare. While we initially did not observe any key changes during the total growth of F. columnare isolates tested when treated with L-rhamnose; it soon became apparent that the difference lies in the ability of this carbohydrate to facilitate the formation of biofilms. The addition of different concentrations of L-rhamnose consistently promoted the development of biofilms among different F. columnare isolates; however it does not appear to be sufficient as a sole carbon source for biofilm growth. Our data also suggest that iron acquisition machinery is required for biofilm development. Finally the addition of different concentrations of L-rhamnose to F. columnare prior to a laboratory challenge increased mortality rates in channel catfish (Ictalurus punctatus) as compared to controls. These results provide further evidence that biofilm formation is an integral virulence factor in the initiation of disease in fish.