Location: Aquatic Animal Health Research
Title: An in vitro screening method to evaluate chemicals as potential chemotherapeutants to control Aeromonas hydrophila infection in channel catfish Authors
Submitted to: Annual Meeting World Aquaculture Society
Publication Type: Proceedings
Publication Acceptance Date: August 17, 2012
Publication Date: February 21, 2013
Citation: Wei Pridgeon, Y., Klesius, P.H., Mu, X., Song, L. 2013. An in vitro screening method to evaluate chemicals as potential chemotherapeutants to control Aeromonas hydrophila infection in channel catfish. Proceeding of Aquaculture America 2013. p. 874. Technical Abstract: Aeromonas hydrophila, a Gram-negative motile bacillus widely distributed in aquatic environments, is a causative agent of motile aeromonad septicaemia (MAS). Although usually considered as a secondary pathogen associated with disease outbreaks, A. hydrophila could also become a primary pathogen, causing outbreaks in fish farms with high mortality rates, resulting in severe economic losses to the aquaculture industry worldwide. To control disease outbreaks caused by A. hydrophila, feeding infected fish with antibiotics-medicated food is a general practice. However, currently in the US, there are only three FDA approved antibiotics for use in aquaculture. The widespread use of the limited number of antibiotics for treating bacteria diseases in aquaculture has led to the development of antibiotic resistance in many fish pathogens worldwide. Therefore, alternative control methods and alternative chemotherapeutants are urgently needed for the aquaculture industry. To develop an in vitro screening method to be used for identifying potential effective chemotherapeutants to control Aeromonas hydrophila infections, catfish gill cells G1B and four chemicals (hydrogen peroxide, sodium chloride, potassium permanganate, and D-mannose) were used in this study. In vitro screening results revealed that, at concentration of 100 mg X L-1, H2O2 was the only chemical tested that was able to completely abolish the invasion of A. hydrophila to catfish gill cells (Figure 1). In vivo virulence studies using live channel catfish through bath immersion confirmed that H2O2 was the only chemical tested that was able to significantly (P<0.001) reduce the mortality (from 90 or 100% to 0 or 20%) caused by A. hydrophila infections. This in vitro screening method using catfish gill cells to identify potential effective chemotherapeutants described here will cut cost in research compared to the method of using live fish to screen lead compounds for fish disease control.