[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other Gram-negative rods](https://durgical.com/en/microbiology/groups/other-gram-negative-rods/) › Vibrio cholerae

[Microbiology](https://durgical.com/en/microbiology/) · [Other Gram-negative rods](https://durgical.com/en/microbiology/groups/other-gram-negative-rods/)

# Vibrio cholerae

- Bacterium
- Gram-negative
- Contact
- Exam priority: high

A bacterium in contaminated water that causes cholera: watery diarrhea so heavy it can kill by dehydration within hours.

Updated 2026-11-01

Also called: cholera vibrio

## Key points

- "Rice-water" diarrhea and fast dehydration: cholera.
- Cholera toxin activates Gs, raises cAMP and pumps out chloride and water (like E. coli LT).
- TCBS agar with yellow colonies; oxidase-positive; grows in alkaline media.
- Main treatment: oral or IV rehydration; antibiotics only in severe cases.
- Only serogroups O1 and O139 cause epidemics.

## At a glance

**Gram**
Gram-negative

**Shape**
Comma-shaped curved rod

**Oxygen**
Facultative anaerobe

**Family**
Vibrionaceae

**Stain**
Gram: curved red rods

## Morphology

- Comma-shaped Gram-negative rod with one polar flagellum: fast "darting" motility
- Oxidase-positive
- Grows on alkaline media: TCBS agar with yellow colonies (ferments sucrose)
- Only serogroups O1 and O139 cause epidemics

## Transmission

- Water or food contaminated with feces, raw shellfish
- Outbreaks where safe water and sanitation are lacking (disasters, camps)
- Contact (on top of standard) for diapered or incontinent patients

**Reservoir:** Humans; Brackish and coastal water (linked to plankton)

### Isolation precautions

What the care team adds to standard precautions.

**Contact**
Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.

## Virulence factors

- Cholera toxin (A-B): the A subunit activates Gs, raises enterocyte cAMP and drives massive chloride and water loss
- Toxin-coregulated pilus (TCP): colonizes the small bowel
- Flagellum and mucinase: cross the mucus
- Acid-sensitive: needs a large inoculum

## Diseases it causes

- Cholera: acute watery diarrhea with severe dehydration [Cholera →](https://durgical.com/en/conditions/cholera/)

## Clinical picture

- Onset from a few hours to 5 days after exposure
- Large, bloodless, "rice-water" stools with a fishy smell
- Vomiting, cramps, hypovolemia, acidosis and shock
- Many infected people have no symptoms but shed the bacterium

## Diagnosis

- Stool culture in alkaline peptone water and on TCBS agar
- Rapid stool antigen tests for outbreak screening
- Confirmation and serotyping at the reference laboratory

## Treatment

Fluid replacement is the core: oral rehydration salts for most patients and intravenous fluids for severe cases. Antibiotics (doxycycline, azithromycin or ciprofloxacin) are given in severe cases to shorten diarrhea; mass antibiotic prophylaxis is not recommended.

Drug class only; doses and regimens are set by the clinician from the current guideline.

In Pharmacology:

- [Doxycycline](https://durgical.com/en/pharmacology/doxycycline/)
- [Azithromycin](https://durgical.com/en/pharmacology/azithromycin/)
- [Ciprofloxacin](https://durgical.com/en/pharmacology/ciprofloxacin/)

## Prevention

- Safe water, sanitation and hygiene
- Inactivated oral vaccines in endemic areas, humanitarian crises and outbreaks
- Cooking shellfish and handwashing

**Vaccine:** WHO-prequalified inactivated oral vaccines; because of the global shortage, campaigns use a single dose. They are not part of Colombia's PAI.

## In Colombia

Cholera reached Colombia in 1991 with the Latin American epidemic, along the Pacific coast; there is no sustained transmission today, but it remains an INS surveillance event because of the risk of imported cases from the Caribbean (Haiti).

## Memory aid

"Cholera jams the cAMP tap open": the toxin leaves the chloride faucet running and the patient pours out rice water.

## Test yourself

Think of the answer, then tap the question to see it.

## How does cholera toxin work?

Its A subunit permanently activates Gs, raises cAMP in the enterocyte and causes massive chloride and water secretion.

## What is the most important treatment for cholera?

Rehydration: oral rehydration salts and, in severe cases, intravenous fluids.

## On which selective medium does Vibrio cholerae grow, and what color are its colonies?

TCBS agar, with yellow colonies because it ferments sucrose.

## Which serogroups cause epidemic cholera?

O1 and O139.

[Add to my cards (4)](https://durgical.app/estudiar/?add=/en/microbiology/vibrio-cholerae/)

## Related

- [Escherichia coli](https://durgical.com/en/microbiology/escherichia-coli/)
- [Campylobacter jejuni](https://durgical.com/en/microbiology/campylobacter-jejuni/)

## Related conditions

- [Cholera](https://durgical.com/en/conditions/cholera/)

## What the colours mean

**Gram-positive**
Thick peptidoglycan wall: stains purple.

**Gram-negative**
Thin wall with an outer membrane: stains pink.

**Acid-fast**
Lipid-rich wall (mycobacteria): Ziehl–Neelsen stain.

**Contact**
Gown and gloves; dedicated equipment. For C. difficile, soap-and-water hand washing.

**Droplet**
Surgical mask within about a metre; single room.

**Airborne**
N95 respirator and a negative-pressure room.

[← Back to the group: Other Gram-negative rods](https://durgical.com/en/microbiology/groups/other-gram-negative-rods/)

Educational content on microorganisms; not a treatment guide and no substitute for a health professional's advice. No doses are given.

Sources: [Cholera](https://www.who.int/news-room/fact-sheets/detail/cholera) (WHO, 2026); [Understanding Cholera: Causes, Symptoms, and Treatment](https://www.paho.org/en/topics/cholera) (PAHO, 2026); [Fichas y Protocolos](https://www.ins.gov.co/buscador-eventos/Paginas/Fichas-y-Protocolos.aspx) (Instituto Nacional de Salud (INS), Colombia, 2026).

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Representative model, for educational purposes only.

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License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/microbiology/vibrio-cholerae/