DAO 59:263-267 (2004)  -  doi:10.3354/dao059263

In vitro effect of a buffered chelating agent and neomycin or oxytetracycline on bacteria associated with diseases of fish

Richard E. Wooley1,*, Branson W. Ritchie2, Victoria V. Burnley2

1Department of Medical Microbiology and Parasitology, and 2Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602-7386, USA

ABSTRACT: The antimicrobial agents used to treat bacterial fish diseases are archaic, and their uses may result in the emergence of drug-resistant bacterial strains. This study evaluated the in vitro antimicrobial activity of combinations of Tricide™ and neomycin or oxytetracycline on common disease-causing bacteria of fish and its possible use as an alternative treatment of these diseases. Tricide™ solutions containing of 8 mM United States Pharmacopeia (USP) disodium ethylenediaminetetraacetate dehydrate (chelator) and 20 mM USP 2-amino-2-hydroxymethyl-1,3-propanediol (buffer) potentate the antimicrobial action of neomycin and oxytetracycline when reacted in vitro with Aeromonas hydrophila, Streptococcus iniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Serial passage of the test organisms in Tricide™ or Tricide™ and neomycin or oxytetracycline did not result in the development of resistant forms. Combinations of Tricide™ and neomycin or oxytetracycline reduced the amount of antibiotics necessary for fish therapy, render drug-resistant bacteria sensitive to antimicrobial therapy, may be used to decontaminate recently shipped fish, and should reduce the formation of antibiotic-resistant forms.


KEY WORDS: Tricide™ · Aquatic infections · Topical treatment · Chelation


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