|GRIFFIN, M - Mississippi State University|
|REICHLEY, S - Mississippi State University|
|GREENWAY, T - Mississippi State University|
|WARE, C - Mississippi State University|
|GAO, D - Mississippi State University|
|GAUNT, P - Mississippi State University|
|YANOUNG, R P - Mississippi State University|
|POUDER, D - University Of Florida|
|HAWKE, J - Mississippi State University|
|SOTO, E - Mississippi State University|
Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/5/2015
Publication Date: 8/1/2016
Citation: Griffin, M.J., Reichley, S.R., Greenway, T.E., Quiniou, S., Ware, C., Gao, D.X., Gaunt, P.S., Yanoung, R.E., Pouder, D.B., Hawke, J.P., Soto, E. 2016. Comparison of Edwardsiella ictaluri isolates from different hosts and geographic origins. Journal of Fish Diseases. 39:(8)947-969.
Interpretive Summary: Edwardsiella ictaluri is an important bacterial pathogen associated with catfish aquaculture in the southeastern United States. Recently it has been identified in other fish hosts from non-endemic regions. This work identified E. ictaluri genotypes associated with different host origins that can be identified by molecular methods, such as repetitive-sequence mediated PCR and gyrB sequence. In addition, this work demonstrates gyrB sequence provides greater resolution than 16S rDNA sequence as a marker for identification and classification of the Edwardsiella.
Technical Abstract: The intraspecific genetic variability of E. ictaluri isolates from different origins was determined. Isolates were recovered from farm-raised catfish (Ictalurus punctatus) in Mississippi, USA, tilapia cultured in the Western hemisphere, and zebrafish propagated in Florida, USA. These isolates were phenotypically homologous and antimicrobial profiles were largely similar. Genetically, isolates possessed subtle differences that could be exploited by repetitive-sequence mediated PCR (rep-PCR) and gyrB gene sequence. Of the four primer sets evaluated, the ERIC I & II, BOX and GTG5 primers produced three distinct profiles unique to their respective groups. Analysis of the gyrB sequence was in agreement with these profiles, identifying three distinct E. ictaluri gyrB genotypes: one associated with catfish, one from tilapia, and a third from zebrafish. The biological significance of these findings is unclear and it is unknown whether these differences are driven by host species, culture practices, geography or other unidentified factors. This work identifies three genetically distinct strains of E. ictaluri from different origins that can be identified using rep-PCR and gyrB sequencing. In addition, this research demonstrates gyrB sequence provides greater resolution than 16S rRNA for identification and classification of the Edwardsiella.