Vibrionaceae and Aeromonadaceae Classification Quiz

The genera classified under the family Vibrionaceae and Aeromonadaceae are Vibrio and Aeromonas. Vibrio is oxidase-positive, catalase-positive, and indole-positive, while Aeromonas is oxidase-positive, catalase-positive, and indole-negative.

The selective ingredients in TCBS agar are sodium citrate, high pH (8.6), and bile salts, which collectively inhibit Gram-positive bacteria and many enterobacteriaceae. The differential ingredients are sucrose and bromthymol blue (which turns yellow in acid conditions), plus sodium thiosulfate and ferric citrate.

On CBA, Vibrio species look similar to other Gram-negative bacteria but may have a greenish hue. On TCBS agar, organisms that ferment sucrose such as V. cholera and V. alginolyticus produce yellow colonies, while non-sucrose fermenting colonies remain colorless (e.g., V. parahaemolyticus and V. vulnificus). Organisms that produce H2S produce a black precipitate.

<p>O/129 is a vibriostatic agent that inhibits the growth of Vibrio species. Its use in culture media helps in differentiating Vibrio species based on their susceptibility or resistance to O/129.</p> Signup and view all the answers

<p>Vibrio species are found in fresh and salt water, as well as in the intestines of humans and other animals. Morphologically, they are Gram-negative straight or curved rods with polar flagella, and are motile by means of polar flagella.</p> Signup and view all the answers