Enterotoxicity of Bacteria-free Culture-filtrate of Vibrio cholerae

Abstract

TWO Ogawa strains of V. cholerae maintained for six months in the laboratory by fortnightly subculture on agar slopes, and two Inaba strains maintained similarly for about eighteen months have been used for this study. All the strains, which were smooth, were checked for their identity and particularly for their inability to lyse sheep red blood cells. 5 ml. of an 18-hr. culture of each strain in Dunham's peptone water medium was aseptically transferred to a 1-litre Roux bottle containing 200 ml. of a sterile medium of the following composition and a pH of 7.6: ‘Bacto-peptone’ (Difco), 5.0 gm.; sodium chloride, 0.5 gm.; water, 100 ml.