Comparison of Edwardsiella ictaluri isolates from different hosts and geographic origins |
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| Authors: | M J Griffin S R Reichley T E Greenway S M Quiniou C Ware D X Gao P S Gaunt R P E Yanong D B Pouder J P Hawke E Soto |
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| Institution: | 1. Thad Cochran National Warmwater Aquaculture Center, Mississippi State University, Stoneville, MS, USA;2. Thad Cochran National Warmwater Aquaculture Center, Warmwater Aquaculture Research Unit, Agricultural Research Service, United States Department of Agriculture, Stoneville, MS, USA;3. Tropical Aquaculture Laboratory, Fisheries and Aquatic Sciences Program, School of Forest Resources and Conservation, Institute of Food and Agricultural Sciences, University of Florida, Ruskin, FL, USA;4. Department of Pathobiological Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA;5. Department of Biomedical Sciences, School of Veterinary Medicine, Ross University, Basseterre, St. Kitts, West Indies |
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| Abstract: | The intraspecific variability of E. ictaluri isolates from different origins was investigated. Isolates were recovered from farm‐raised catfish (Ictalurus punctatus) in Mississippi, USA, tilapia (Oreochromis niloticus) cultured in the Western Hemisphere and zebrafish (Danio rerio) propagated in Florida, USA. These isolates were phenotypically homologous and antimicrobial profiles were largely similar. Genetically, isolates possessed differences that could be exploited by repetitive‐sequence‐mediated PCR and gyrB sequence, which identified three distinct E. ictaluri genotypes: one associated with catfish, one from tilapia and a third from zebrafish. Plasmid profiles were also group specific and correlated with rep‐PCR and gyrB sequences. The catfish isolates possessed profiles typical of those described for E. ictaluri isolates; however, plasmids from the zebrafish and tilapia isolates differed in both composition and arrangement. Furthermore, some zebrafish and tilapia isolates were PCR negative for several E. ictaluri virulence factors. Isolates were serologically heterogenous, as serum from a channel catfish exposed to a catfish isolate had reduced antibody activity to tilapia and zebrafish isolates. This work identifies three genetically distinct strains of E. ictaluri from different origins using rep‐PCR, 16S, gyrB and plasmid sequencing, in addition to antimicrobial and serological profiling. |
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| Keywords: |
Edwardsiella
catfish tilapia zebrafish |
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