In vitro effect of ethylenediaminetetraacetic acid-tris on the efficacy ofhatchery disinfectants

Solutions of ethylenediaminetetraacetic acid (EDTA)-Tris showed synergistic or additive effects on gram-negative bacteria when combined with hatchery disinfectants consisting of phenol and detergent (Magnaphen-100), quaternar y ammonium compound (QAC) and glutaraldehyde (Synergize), QAC (BioSentry 90 4), and hydrogen peroxide. The gram-positive bacteria reacted less favorabl y, with reaction mixtures showing all three levels of potentiation (synergi stie, additive, and antagonistic). Combinations of EDTA-Tris and a commerci al glutaraldehyde solution (Glutracide), when mixed with the test organisms , showed mostly antagonistic effects. Solutions of EDTA-Tris decreased the concentration of hatchery disinfectants required for bacterial killing by 7 5% in those situations in which synergistic potentiation occurred. EDTA-Tris is nontoxic to 12-day-old embryos. Serial passage of the test org anisms in solutions of EDTA-Tris did not result in the development of resis tant forms.