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United States Department of Agriculture

Agricultural Research Service

Research Project: Integrated Aquatic Animal Health Strategies

Location: Aquatic Animal Health Research

Title: Attenuation of a virulent Aeromonas hydrophila with novobiocin and pathogenic characterization of the novobiocin-resistant strain

Authors
item Wei Pridgeon, Yuping
item Aksoy, Mediha -
item Klesius, Phillip

Submitted to: Aquaculture America Conference
Publication Type: Proceedings
Publication Acceptance Date: August 30, 2013
Publication Date: February 9, 2014
Citation: Wei Pridgeon, Y., Aksoy, M., Klesius, P.H. 2014. Attenuation of a virulent Aeromonas hydrophila with novobiocin and pathogenic characterization of the novobiocin-resistant strain. Proceedings Aquaculture America 2014. p. 425.

Technical Abstract: A novobiocin-resistant strain AH11NOVO was obtained from a virulent A. hydrophila strain AH11P through selection of resistance to novobiocin. AH11NOVO was found to be avirulent to channel catfish (Ictalurus punctatus) whereas AH11P was virulent. When AH11NOVO vaccinated channel catfish were challenged with AH11P at 14 days post vaccination, relative percent of survival of vaccinated fish was 100%. The cell proliferation rate of AH11NOVO was found to be significantly (P<0.05) less than that of AH11P (Figure 1). In vitro motility assay revealed that AH11NOVO was non-motile whereas AH11P was motile. AH11NOVO had significantly (P<0.05) lower in vitro chemotactic response to catfish mucus than that of AH11P. Although the ability of AH11NOVO to attach catfish gill cells was similar to that of AH11P, the ability of AH11NOVO to invade catfish gill cells was significantly (P<0.05) lower than that of AH11P (Figure 2). Our results suggest that the novobiocin-resistant AH11NOVO is attenuated and different from its parent AH11P in pathogenicity. The significantly lower chemotactic response and invasion ability of AH11NOVO compared to that of its virulent parent strain AH11P might shed light on the pathogenesis of A. hydrophila.

Last Modified: 9/20/2014
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