Testing a Refugium and Phytoremedial Device for the Control of a Pathogenic Strain of Aeromonas sobria
IAAAM 2005
Julius M. Tepper1; Tirath S. Sandhu2
1Long Island Fish Hospital, Shirley, NY, USA; 2Cornell University Duck Research Laboratory, Dept. of Population Medicine and Diagnostic Sciences, Eastport, NY, USA


Based on clinical evidence suggesting superior control of ulcer disease in hospitalized koi, the hospital quarantine setup first described in 2004, using a refugium with upflow filtration and a phytoremedial device, was tested to prove its ability to control the growth of a pathogenic strain of the bacteria Aeromonas sobria.

After an outbreak of naturally occurring ulcer disease in a koi pond, a specimen was hospitalized for treatment. A culture was taken upon admission. The results were a marked growth of Aeromonas sobria. The bacteria was grown and maintained in the lab in tryptose soy broth. An experimental setup based on one previously described1 was constructed using two identical 10-gals. (37.85l.) tanks. Each was fitted with a 2-gal. (7.56l.), 4" (10.16cm.) deep refugium. Water was circulated to the refugium via a submersible pump valved to deliver 100 gal. /hr. Each tank was fitted with a 200 watt heater and maintained at 24°C. The water in each setup was enriched with 18 ml of tryptose soy broth and inoculated with 5 ml of the Aeromonas sobria culture to give a starting dilution (0hrs.) of 7.7± 0.1 x104 colony forming units/milliliter of tank water (CFU/ml.). A floating, phytoremedial device, unplanted and inert, was placed in the control unit refugium. A biologically active unit, consisting of a live Impatiens (Impatiens sp.) plant grown in a koi pond for several weeks prior to testing, was placed in the test unit. Sampling was done of the effluent of each refugium at 8, 16, 24 and 48 hrs. post inoculation. Viable bacteria were determined by tenfold serial dilution and colony count method by plating on blood agar plates. The results are given below in CFU/ml (x million).

Results: The control unit allowed exponential growth of the bacteria. This would be expected in enriched water environments under ideal growth conditions, as might be found in a newly set up quarantine- treatment unit. In the test unit, the device controlled bacterial growth near starting levels and impeded the explosive growth seen in the control unit.



1.  Tepper JM. Proceedings IAAAM 2000, 2004

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Julius M. Tepper, DVM