Some Factors Affecting the Properties of Quaternary Ammonium Compounds as Sanitizers

Site of action of Polymyxin on Pseudomonas aeruginosa: Antagonism by Cations

“…There is no evidence for chelation between polymyxin and cations (Newton, 19533); the results presented in the present paper indicate that the antagonism of this antibiotic by cations is due to a competition between the cations and polymyxin for sites on the cells. In this respect polymyxin appears to resemble cationic detergents ; a number of workers have described competition between non-toxic cations and toxic surface active cations (Valko & DuBois, 1944;Ridenour & Armbrustin, 1948 ;Massart, 1952).…”

Conservation of the Exterior of the National Museum of the American Indian Building

“…Bartolini et al (2004) have shown that although quatbased biocides have a high extraction capacity for pigments, such as green chlorophyll a, orange β-carotene, and the brown scytonemin contained in dark cyanobacteria biofilms, these pigments can remain embedded in stone even after the organisms have been eliminated (Delgado Rodrigues and Valero, 2003). The effectiveness of quats as a biocide was found to be reduced by more than 90% when mixed with hard water, that is, with concentrations of calcium and magnesium ions greater than about 10 ppm (Ridenour and Armbruster, 1948). As a reference, moderately hard water, such as the tap water in Washington, D.C., contains between 70 and 120 ppm of calcium and magnesium ions, hard water contains between 120 and 180 ppm, and very hard water contains over 180 ppm.…”

Un nouvel agent antimicrobien: le dibromure de déditonium

“…Après contact de 10 minutes à 22° C, des subcultures de 1 ml sont effectuées dans 10 ml de «letheen broth» (11) (15), additionné de billes de verre pour faciliter l'homogénéisation (5); à partir de ce milieu liquide, une deuxième subculture de 1 ml est incorporée dans 10 ml d'une gélose à la lécithine, fondue, et coulée en suite en boîtes de Pétri (16). Ce milieu solide permet le dénombrement du pour centage de germes survivants par rapport au nombre de germes introduits.…”