What is the best medium for recovery and identification of V. cholerae from a symptomatic patient returning from South America?

The best medium for the recovery and identification of Vibrio cholerae is TCBS agar (Thiosulfate Citrate Bile Salts Sucrose agar). This selective agar is specifically designed for the isolation of Vibrio species, particularly V. cholerae, from clinical samples. The unique formulation of TCBS agar allows V. cholerae to flourish while inhibiting the growth of most other bacteria, which is crucial given the typically diverse flora present in fecal specimens.

TCBS agar contains sucrose, which V. cholerae ferments to produce yellow colonies, facilitating easy differentiation from other non-fermenting Vibrio species that remain greenish on the medium. The selective components, including bile salts and thiosulfate, provide an environment that supports the recovery of enteric pathogens while suppressing the growth of competing flora.

In contrast, while MacConkey agar is useful for isolating gram-negative bacteria, it is primarily used for enteric gram-negative rods and may not be as effective for specific Vibrio isolation due to potential inhibition of their growth. Blood agar is primarily used for isolating fastidious organisms and detecting hemolysis, which is not particularly suited for Vibrio species. XLD agar, while