Quaternary ammonium compounds. A new technique for the study of their bactericidal action and the results obtained with cetavlon (Cetyltrimethylammonium bromide)

Abstract

1. Some sources of error in the testing of quaternary ammonium compounds for bactericidal activity have been investigated. These resolve themselves into (a) errors caused by bacteriostasis, and (b) errors caused by the clumping of bacteria.2. A suitable technique, free from these errors, is described.3. Cetavlon in 0·1% solution is a powerful bactericide even in the presence of moderate amounts of organic matter.4. One per cent Cetavlon will not kill spores at room temperature even when contact is maintained for several days.5. Bacteria surviving the action of quaternary ammonium compounds retain their virulence.