Bactericidal and sporicidal activities of an improved iodide formulation and its derivative

Bactericidal and sporicidal activities of an improved iodide formulation (tentatively designated as the distilled KMT reagent: pH around 3) and its derivative (tentatively designated as the distilled ethanol reagent: pH around 2.5) were examined in several dilutions against vegetative bacteria and Bacillus subtilis spores, and they were compared with two kinds of intermediate-level disinfectants, i.e., 7% povidone-iodine (ISODINE) and ethanol for disinfection (76.9-81.4 vol %). Each solution of distilled KMT reagent up to a dilution of 1:100 showed potent bactericidal activity against most tested bacteria when used for 30 seconds at 20 degrees C. Bactericidal activities at these dilutions were almost comparable with those of the same dilution of ISODINE. Although the 1:10 dilution of ISODINE did not show comparable sporicidal activity, the same dilution of distilled KMT reagent showed potent sporicidal activity. On the other hand, the 1:2 dilution of distilled ethanol reagent showed potent sporicidal activity when used for 5 minutes at 60 degrees C. Ethanol for disinfection did not show any sporicidal activity even with treatment for 60 minutes at 60 degrees C. With treatment for 30 sec at 37 degrees C, the 1:2 dilution of distilled ethanol reagent was found to have effective bactericidal activity almost comparable with that of ethanol for disinfection. Appropriate dilutions of both the distilled KMT reagent and distilled ethanol reagent may be applicable as antiseptics which are able to achieve high-level disinfection.