Isolation of rapidly lactose-fermenting Vibrio choleraeStrains

Abstract

Fifty-seven of 131 strains of Vibrio cholerae that were isolated in Calcutta durin an outbreak of cholera in April and May 1970 fermented lactose after overnight incubation in Andrade's peptone water and in TSI medium. All the rapid fermenters of lactose belonged to the classical biotype, to serotype O-I, Inaba, and to phage-type 1. V. cholerae strains are usually non-fermenters or late fermenters of lactose. A deviation from this previously accepted finding may cause error in identification. The inclusion of the lysine-decarboxylase and oxidase tests helps to overcome this difficulty.