Location: Aquatic Animal Health ResearchTitle: A preliminary exploration of columnaris-causing bacteria isolated from cultured largemouth bass (Micropterus salmoides) in the southeastern United States
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 7/17/2023
Publication Date: 7/24/2023
Citation: Johnston, A.E., Garcia, J.C., Lafrentz, B.R., Bruce, T.J., Beck, B.H. 2023. A preliminary exploration of columnaris-causing bacteria isolated from cultured largemouth bass (Micropterus salmoides) in the southeastern United States [abstract]. 2023 Joint Meeting of the Northeast Fish Health Committee and the AFS Fish Health Section, Burlington, VT. July 24-28, 2023. 38.
Technical Abstract: Largemouth bass aquaculture is a multi-million dollar industry, largely comprised of sales for recreational stocking purposes. However, advances in production have allowed for the culture of largemouth bass as a food fish and the demand is growing substantially. Columnaris disease has been detected and associated with disease and mortality events in both wild and cultured largemouth bass nationwide and is a disease of considerable concern in the southeastern US. Over the past few years, our research team has collected a panel of isolates associated with columnaris disease outbreaks in largemouth bass. Given the recent speciation of columnaris-causing bacteria (CCB), we sought to explore the genetic diversity of this panel of CCB isolates. Multiplex PCR was used to identify the species of each isolate and the gyrB gene of each isolate was sequenced and phylogeny determined. The results revealed F. covae and F. columnare were commonly associated with the largemouth bass columnaris disease cases of the present study. Sequencing of the gyrB gene revealed 100% identity among the F. covae isolates and some diversity among the F. columnare isolates recovered from different cases and facilities. The results of the present study represent the first step towards a greater understanding of CCB impacting the largemouth bass industry in the southeastern US. Further, these results provide guidance for the development of targeted disease prevention and control methods, a need which will be highlighted herein by detailing a recent case wherein columnaris disease was identified as the culprit behind a significant mortality event at a largemouth bass aquaculture facility.