Vibrio cholerae Overview and Pathogenesis

What is the primary effect of increased intracellular cAMP levels in the context of cholera?

What is characterized by the term 'rice water stool' in cholera?

Which clinical finding is NOT typically associated with cholera?

What is the recommended treatment for dehydration caused by cholera?

Which of the following is an ineffective prevention method for cholera?

What shape do Vibrio cholerae bacteria have?

Which pathway primarily transmits Vibrio cholerae?

What is the main virulence factor produced by Vibrio cholerae?

What is the role of the A1 subunit in cholera toxin's mechanism of action?

Where do Vibrio cholerae bacteria primarily attach in the human body?

What is a characteristic feature of Vibrio cholerae concerning salt?

What is the typical incubation period for a cholera infection?

What happens when the A subunit of cholera toxin dissociates?

Vibrio cholerae Overview

Gram-negative, oxidase-positive, motile rod-shaped bacteria
Salt-tolerant or salt-requiring
Found in freshwater ponds and brackish water
Cultivable on standard stool culture media
Causes cholera disease

Transmission

Transmitted by the fecal-oral route (contaminated food/water)
Large infectious dose required; person-to-person transmission is less common
Recovered cholera patients can shed the bacteria, acting as reservoirs in endemic areas

Pathogenesis

Incubation period: 6 hours to 3 days
Adheres to intestinal microvilli after crossing the stomach acid barrier
Multiplies, producing potent cholera toxin (enterotoxin)
Toxin acts on GM1 ganglioside receptors on intestinal cells
Cholera toxin's A1 subunit activates adenylate cyclase
Activates adenylate cyclase, increasing intracellular cAMP
This leads to sodium, potassium, and chloride loss (Hypersecretion of Cl− and HCO3−)
Water and electrolytes lost in stool (rice-water stool), leading to dehydration, acidosis, and shock

Clinical Findings

Sudden vomiting
Profuse watery diarrhea (rice-water stool) with abdominal cramps
Rapid fluid loss and electrolyte depletion causing dehydration, circulatory collapse, and anuria
High mortality rate (25-50%) without treatment

Diagnosis

Stool or vomitus culture

Treatment

Fluid and electrolyte replacement therapy
Effective antimicrobial therapies (e.g., oral tetracycline)

Prevention

Improved public sanitation to reduce fecal contamination of water sources
Avoiding contaminated food/water
Boiling drinking water
Handwashing
Vaccination is short-term in providing protection.

Explore the characteristics and pathogenesis of Vibrio cholerae, the bacteria responsible for cholera disease. This quiz covers its transmission, cultivation, and the effects of cholera toxin on the human body. Test your knowledge on this important pathogen and its impact on health.