PRETEST VIBRIO

Which of the following is the selective medium used to isolate Vibrio cholerae, and what is the characteristic appearance of its colonies?

• Blood agar; bright red colonies

• MacConkey agar; cloudy white colonies

• Nutrient agar; transparent colonies

• TCBS agar; green colonies due to glucose fermentation

• TCBS agar; yellow colonies due to sucrose fermentation

What is the primary role of the toxin-coregulated pilus (TCP) in the pathogenesis of Vibrio cholerae?

• It destroys epithelial cells

• It induces secretory diarrhea

• It aids in intestinal colonization and microcolony formation

• It activates adenylate cyclase

• It causes systemic tissue damage via toxin

In taxonomy, Vibrio cholerae belongs to which class?

• Alphaproteobacteria

• Firmicutes

• Gammaproteobacteria

• Betaproteobacteria

• Actinobacteria

Which clinical symptom is most characteristic of cholera and distinguishes it from other diarrheal diseases?

• Bloody diarrhea with high fever

• Foamy stools with thick mucus

• Black stools with severe abdominal pain

• Watery, colorless, and odorless stools described as “rice-water stools”

• Yellow-green diarrhea with foul smell

Which of the following statements about cholera vaccines is incorrect?

• The vaccine is administered orally

• It is used mainly during outbreaks or in endemic regions

• There are both killed-cell and live-attenuated vaccine types

• The vaccine provides lifelong immunity

• Dukoral is one example of an oral cholera vaccine