Submitted to: American Society of Microbiologists Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2005
Publication Date: 6/5/2005
Citation: Shoemaker, C.A., Arias, C.R., Klesius, P.H., Welker, T.L. 2005. Whole cell fatty acid profiles of flavobacterium columnare from fish. American Society of Microbiologists Abstracts. 105th General Meeting of the American Society for Microbiology. Atlanta, GA June 5-9, 2005.
Technical Abstract: Background: Flavobacterium columnare is a significant pathogen of many species of cultured and wild fish. Flavobacterium columnare does not grow on standard media and is not included in rapid commercial bacterial identification systems. The goal of our study was: 1) to describe the biochemical characteristics from 3 ATCC isolates and 29 F. columnare isolated from diseased freshwater fish and 2) to describe their fatty acid profiles using gas chromatography. Methods: Standard biochemical tests (e.g., starch hydrolysis, gelatin hydrolysis, utilization of sugars, etc.) were completed to identify F. columnare, and the microbial identification system (MIS; Microbial ID, Newark, DE ) was used to generate the fatty acid profiles. Briefly, F. columnare were grown in modified Shieh broth for 48 h prior to extracting the fatty acids for gas chromatography using the CLIN40 or RCLIN50 protocol as established by MIS. Results: The fatty acid methyl esters of F. columnare consisted of 10 major fatty acids (represented by greater than 1 percent): 13:0 ISO, 15:1 ISO G, 15:0 ISO, 15:0 ANTEISO, 15:0, 16:0 ISO, 15:0 ISO 3OH, ISO 17:1 w9c, 16:0 ISO 3OH and 17:0 ISO 3OH. The predominant fatty acids from all isolates included: 15:1 ISO G (16.12%), 15:0 ISO (46.54%), 15:0 ISO 3OH (6.81%), ISO 17:1 w9c (7.32%) and 17:0 ISO 3OH (9.42%). The F. columnare isolates tested clustered at 97% similarity (Pearson product- moment correlation coefficient), thus only a single group based on fatty acid profiles was found within the species confirming the high phenotypic homology. Conclusion: Fatty acid profiles of F. columnare are a rapid and reliable means of identifying this bacterium. However, the high degree of phenotypic homology within fatty acid profiles will preclude biotype tracking of a single F. columnare isolate.