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United States Department of Agriculture

Agricultural Research Service

Research Project: AQUATIC ANIMAL DIAGNOSTICS, PATHOGENESIS AND APPLIED EPIDEMIOLOGY

Location: Aquatic Animal Health Research

Title: Development of a culture independent method to characterize the chemotactic response of Flavobacterium columnare to fish mucus

Authors
item Lafrentz, Benjamin
item Klesius, Phillip

Submitted to: Journal of Microbial Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 22, 2008
Publication Date: January 3, 2009
Repository URL: http://hdl.handle.net/10113/32012
Citation: Lafrentz, B.R., Klesius, P.H. 2009. Development of a culture independent method to characterize the chemotactic response of Flavobacterium columnare to fish mucus. Journal of Microbial Methods. 77:37-40.

Interpretive Summary: Flavobacterium columnare is a Gram-negative bacterial fish pathogen that causes columnaris disease and is considered to be one of the most important pathogens impacting the channel catfish industry in the United States. Recent research has demonstrated that F. columnare exhibits a chemotactic response (i.e., movement of the bacteria in reaction to a substance) towards the mucus from the skin of catfish and this response may be important for pathogenesis. The typical method used to characterize chemotaxis of bacteria is tedious and labor/time intensive due to the requirement of culturing the bacteria. In this study, a simple, rapid, and culture independent method was developed which will enhance the ability to further characterize the chemotactic response of F. columnare to fish mucus. Such research will increase the understanding of this host-pathogen relationship and may identify novel control strategies for the prevention of columnaris disease.

Technical Abstract: Flavobacterium columnare, the causative agent of columnaris disease, is a significant pathogen of many freshwater fish species worldwide and is considered one of the most important pathogens impacting the channel catfish (Ictalurus punctatus Rafinesque) industry in the United States. Recent research has demonstrated that F. columnare exhibits a chemotactic response to the mucus from the skin of catfish and this response may be important for pathogenesis. In this study, a culture independent method was developed to quantify the chemotactic response of F. columnare to skin mucus. The method employs the use of blind-well chemotaxis chambers which overcomes difficulties using the traditional capillary tube assay and uses a cell proliferation assay to quantify viable cells which reduces the time and labor associated with culturing the bacterium. Application of the method to two sets of catfish skin mucus samples demonstrated that there is variation in the chemotactic response of F. columnare to individual catfish mucus samples, and similar results were obtained to previously published research using the traditional capillary tube method. The use of this method will enhance the ability to further characterize the chemotactic response of F. columnare to catfish skin mucus in order to increase our understanding of this important host-pathogen interaction.

Last Modified: 8/27/2014
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