Which medium is preferred for recovering Vibrio cholerae from stool specimens?

Thiosulfate-citrate-bile sucrose (TCBS) agar is specifically designed for the selective isolation of Vibrio species, particularly Vibrio cholerae, from clinical specimens such as stool. This medium contains components that inhibit the growth of non-Vibrio bacteria while promoting the growth of Vibrio species. The high concentration of bile salts in TCBS agar is effective in suppressing competing flora from the gastrointestinal tract, which is crucial when analyzing stool specimens. Moreover, the addition of sucrose allows for the differentiation of V. cholerae from other vibrios, as V. cholerae ferments sucrose and produces yellow colonies on this medium, while non-sucrose fermenting vibrios will not change the color of the medium.

In the context of the other options, while MacConkey agar and thioglycollate media might support the growth of a broad range of enteric bacteria, they are not specific for Vibrio cholerae. Blood agar and selenite-F broth are used for different purposes, such as general bacterial isolation and enrichment for Salmonella and Shigella, not specifically for Vibrio species. CNA agar is a selective medium used primarily for gram-positive organisms, making it unsuitable for isolating