The Isolation ofEscherichia coliPhage by Means of Cationic Detergents

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Abstract
Previous reports have shown that 7 coli phase is highly resistant to the germicidal activity of detergents. Because of this high resistance, various detergents were tested in order to ascertain their usefulness in isolating this phage directly from sewage. The detergents employed were the cationic detergents; Zephiran, Phemerol, Cetyl pyridin-ium chloride, and Emulsol-607. These compounds were used in a final dilution of 1:5,000. To appropriate dilutions of the compounds, raw sewage, either with or without a preliminary incubation in the presence of a culture of E. coli, was added. Usually 2 ml. of 1:1,000 detergent was added to 8 ml. of test material. These mixtures were allowed to stand for 1/2 hr. at room temp, and then added to a 3-4 hr. culture of E. coli. 1 ml. mixture being added to every 50 ml. culture. After 24 hrs.'' incubation at 37[degree]C, the material was centri-fugated and the supernatant retreated with its respective detergent. Phage was obtained in its greatest conc, in the 2d passage. The preliminary incubation in the presence of E. coli gave the greater phage yield. The results obtained show that the detergents Emulsol-607, Zephiran, and Cetyl pyridinium chloride yielded more phage than nitration in the isolation of coli phage directly from sewage.