Mississippi State University
Matt J. Griffin
Lester H. Khoo
Date of Degree
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Graduate Thesis - Open Access
Wildlife, Fisheries and Aquaculture
Master of Science
College of Forest Resources
Department of Wildlife, Fisheries and Aquaculture
The gram-negative bacteria Edwardsiella ictaluri causes significant economic losses in aquacultured fish. Generally considered host-specific to catfish, there are reports of E. ictaluri outbreaks from other aquacultured species, including ornamental fish raised in the southeastern U.S. Thus, a comprehensive phenotypic and genotypic characterization of E. ictaluri isolates from catfish and ornamental aquaculture was warranted. Morphological, biochemical, and protein profiles of catfish and ornamental derived isolates were mostly similar. Plasmid profiles of wild-type isolates were consistent within groups. Analysis of putative anti-microbial resistant isolates from catfish revealed the presence of multi-drug resistant plasmids. Genomic comparisons indicated marked differences among host groups, including unique T4SSs and phage elements among ornamental fish-derived E. ictaluri isolates. An optimal MLSA scheme consisting of eight reference genes was defined, revealing isolates from catfish and ornamental aquaculture form two discrete phyletic lineages. This study advances our understanding of E. ictaluri affecting two important agricultural commodities in the U.S.
USDA National Institute of Food and Agriculture (NIFA) Southern Regional Aquaculture Centre (SRAC)
Divya, Divya, "Phenotypic and genotypic characterization and comparison of Edwardsiella ictaluri isolates derived from catfish and ornamental fish species" (2021). Theses and Dissertations. 5202.
Available for download on Tuesday, August 15, 2023