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United States Department of Agriculture

Agricultural Research Service

Title: Genomic Subtyping of Edwardsiella Ictaluri Isolated from Diseased Channel Catfish by Arbitrarily Primed Polymerase Chain Reaction.

Authors
item Bader, Joel
item Shoemaker, Craig
item Klesius, Phillip

Submitted to: Journal of Aquatic Animal Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 22, 1997
Publication Date: N/A

Interpretive Summary: Edwardsiella ictaluri is a major bacterial fish pathogen and is the causative agent of Edwardsiella Septicemia of channel catfish Ictaluri punctatus (ESC). This bacteria was thought to be, prior to this study, homogenous at an intraspecies level. Our study demonstrates that this is not accurate. The present study was conducted to try to subgroup E. ictaluri. Biochemical analysis and Arbitrarily Primed Polymerase Chain Reaction (AP-PCR) were used to subgroup the bacteria. AP-PCR utilized a Enterobacterial Repetitive Intergenic Consensus PCR primer (ERIC II) to genomically subtype 19 isolates of E. ictaluri from channel catfish from throughout the Southeastern United States, an American Type Culture Collection reference strain, and an isolate from a walking catfish, Clarias batrachus from Thailand. Four major subgroupings of E. ictaluri were observed. These subgroups were distributed with the following prevelences: subgroup 1 (55%), subgroup 4 (20%), 2 (15%), and 3 (10%). Biochemical analysis showed biochemical homogeneity among isolates and was not useful for discriminating between isolates.

Technical Abstract: Arbitrarily Primed Polymerase Chain Reaction (AP-PCR) utilizing a Enterobacterial Repetitive Intergenic Consensus PCR primer (ERIC II) to genomically subtype 19 isolates of Edwardsiella ictaluri from channel catfish from throughout the Southeastern United States, an American Type Culture Collection reference strain, and an isolate from a walking catfish, Clarias batrachus from Thailand. Four major subgroupings of E. ictaluri were observed. These subgroups were distributed with the following prevelences: subgroup 1 (55%), subgroup 4 (20%), 2 (15%), and 3 (10%). Biochemical analysis showed biochemical homogeneity among isolates and was not useful for discriminating between isolates.

Last Modified: 4/21/2014
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