TCBS AGAR (MODIFIED)

Description

TCBS Agar was first formulated by Nakanishi and further modified by Kobayashi et al. It promotes rapid growth of pathogenic Vibrio’s after 24 hours incubation at 37?C. The contaminating non-vibrio’ s are suppressed. Strains of Vibrio cholerae produce yellow colonies on TCBS Agar because of fermentation of sucrose. Vibrio alginolyticus also produce yellow colonies. Vibrio parahaemolyticus is a sucrose non-fermenting organism and produces blue-green colonies, as of Vibro vulnificus. As mentioned previously, occasional isolates of Pseudomonas and Aeromonas species also produce blue-green colonies, but overall TCBS Agar is highly selective and any H2S-negative colony is possibly Vibrio species. The medium should be inoculated heavily with faecal specimens because some Vibrio species readily die off on the medium, owing to fermentation of sucrose and accumulation of acids.