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ARS Home » Southeast Area » Stuttgart, Arkansas » Harry K. Dupree Stuttgart National Aquaculture Research Cntr » Research » Publications at this Location » Publication #206419
Title: In vitro and in vivo evaluation of potassium permanganate treatment efficacy for the control of acute experimental infection of flavobacterium columnare in channel catfish

Author
item Darwish, Ahmed
item Mitchell, Andrew
item HOBBS, MELISSA - 6225-10-00

Submitted to: North American Journal of Aquaculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/24/2007
Publication Date: 7/1/2008
Citation: Darwish, A.M., Mitchell, A.J., Hobbs, M.S. 2008. In vitro and in vivo evaluation of potassium permanganate treatment efficacy for the control of acute experimental infection of flavobacterium columnare in channel catfish. North American Journal of Aquaculture. 70:314.322.

Interpretive Summary: Columnaris disease, caused by the bacterium Flavobacterium columnare, exists worldwide and affects a wide variety of fish. In the United States, columnaris is the second most costly disease to the channel catfish industry after enteric septicemia of channel catfish. Because of the serious losses attributed to the disease, therapeutants are needed to control columnaris. The present study was designed to assess the effectiveness of potassium permanganate for inhibiting F. columnare in the aquatic environment and in fish exhibiting an acute infection. The results demonstrated that potassium permanganate will have potential benefit for reducing the number of F. columnare in the water thus preventing further contraction of the disease. The results also demonstrated that in acute and severe cases of columnaris the therapeutic value of potassium permanganate might be limited but further research is warranted to investigate potassium permanganate ability to prevent columnaris infection and to treat fish with milder cases of the disease.

Technical Abstract: An experimental trial was performed to evaluate the efficacy of potassium permanganate against an acute and systemic experimental infection of Flavobacterium columnare in channel catfish, Ictalurus punctatus. The infection was produced by waterborne exposure to the bacteria after mechanical cutaneous abrasion to remove mucus and epithelium. Fish were treated 22 h post bacterial challenge with 2.3 mg/L of potassium permanganate (KMnO4), 2.0 mg/L above the KMnO4 demand, for 8 h. Potassium permanganate did not reduce the mortalities of experimentally infected fish. In vitro, F. columnare treated with KMnO4 at 2 mg/L for 8 h had a 70 % colony forming unit count (CFU) reduction. A minimum concentration of 10 mg/L of KMnO4 was needed to inhibit bacterial growth. The infection model utilized in the experiment was evaluated by examining the clinical signs and the histopathology of infected fish. Fish in the model showed columnaris signs similar to a natural infection: skin depigmentation and ulceration and gill necrosis. Histologically, the skin had severe ulcerative necrotizing dermatitis and the muscles had severe necrotizing myositis. The gills had severe multifocal necrotizing branchitis involving the lamellar and filament epithelium, the pillar cells and the central venous sinus. Heavy bacterial aggregates of long rods were associated with the necrotic cellular debris. The identity of the bacteria isolated from the challenged fish was confirmed by polymerase chain reaction. The results suggest KMnO4 would be beneficial for reducing F. columnare load in the water column and possibly on fish but KMnO4 therapeutic value would be limited in fish with an acute and systemic columnaris infection. Further research would be warranted to investigate KMnO4 value as a therapeutant for fish with a milder columnaris infection and as a treatment to prevent further spread of columnaris in a fish population.