Submitted to: Journal of Applied Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2004
Publication Date: 8/1/2004
Citation: Arias, C.R., Welker, T.L., Shoemaker, C.A., Abernathy, J.W., Klesius, P.H. 2004. Genetic fingerprinting of Flavobacterium columnare isolates from cultured fish. Journal of Applied Microbiology. 97:421-428. Interpretive Summary: In this paper we analyze the instraspecific variability of Flavobacterium columnare isolates from cultured fish. Genetic diversity of this fish pathogen was evaluated using three different fingerprinting methods: restriction fragment length polymorphism (RFLP) of the 16S ribosomic gene, intergenic spacer region (ISR) sequence, and amplified fragment length polymorphism (AFLP). Thirty Fl. columnare strains from different sources were analyzed using these three methods. Our results confirmed the polyphyletic nature of Fl. columnare isolates from fish. We showed that genomovar I and II (previously described) are present in the channel catfish from the USA. We described a unique group within the species formed by isolates from Brazil. The three methods were able to find genetic differences between isolates, however, AFLP was the technique with the highest resolution level.
Technical Abstract: Genetic variability among Flavobacterium columnare isolates was characterized using restriction fragment length polymorphism (RFLP) analysis of the 16S rDNA gene, intergenic spacer region (ISR) sequencing, and amplified fragment length polymorphism (AFLP) fingerprinting. Thirty Fl. columnare cultures isolated from different fish species and geographic origins as well as reference strains were included in the study. Fifteen isolates belonged to genomovar I while eleven were ascribed to genomovar II. Four isolates obtained from tilapia in Brazil could not be assigned to genomovar. Analysis of the IRS sequence confirmed the genetic differences between both genomovars but revealed a higher degree of diversity among genomovar I isolates. The maximum resolution was provided by AFLP fingerprinting, since up to 22 AFLP profiles could be defined within the species.