Marsha L. Landolt Jerry E. Ongerth Ronald J. Pascho 1995 <p><span>Salmonid fishes contract bacterial kidney disease by vertical or horizontal transmission of the pathogenic bacterium, </span><i>Renibacterium salmoninarum</i><span>. Procedures to reduce vertical transmission are under evaluation, but methods are still needed to eliminate sources of waterborne </span><i>R. salmoninarum</i><span>. We examined the efficacy of chlorine to inactivate </span><i>R. salmoninarum</i><span>. The bacterium was exposed to various levels of chlorine at pH 6, 7, or 8, and at 7.5 °C or 15 °C. At pH 7 and 15 °C, 99% inactivation occurred within 18 s, even at free chlorine concentrations as low as 0.05 mg/l. Chlorine was most effective at neutral or acidic pH, and 15 °C. The inactivation curves for 7.5 °C and pH 7, or 15 °C and pH 8, deviated from first-order kinetics by exhibiting shoulders or a tailing-off effect, suggesting that chlorine and the bacterial cells were not the sole reactants. A plot of the concentration-time (</span><i>Ct</i><span>) products for free chlorine at pH 7 and 15 °C produced a line with a slope less than 1, indicating that the duration of exposure was more important than the concentration of free chlorine. These data indicate that </span><i>R. salmoninarum</i><span> is very sensitive to chlorine, and that this disinfectant may be appropriate for use in fish hatcheries rearing salmonids affected by bacterial kidney disease.</span></p> application/pdf 10.1016/0044-8486(94)00361-Q en Elsevier Inactivation of Renibacterium salmoninarum by free chlorine article