[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Other clinically important bacteria](https://durgical.com/en/microbiology/groups/other-clinically-important-bacteria/) › Vibrio vulnificus and Vibrio parahaemolyticus

[Microbiology](https://durgical.com/en/microbiology/) · [Other clinically important bacteria](https://durgical.com/en/microbiology/groups/other-clinically-important-bacteria/)

# Vibrio vulnificus and Vibrio parahaemolyticus

- Bacterium
- Gram-negative
- For completeness

Seawater vibrios: diarrhoea from raw shellfish and wound infections that can kill people with liver disease.

Updated 2026-11-01

Also called: non-cholera vibrios

## Key points

- Cirrhosis + raw oysters + sepsis with bullae: Vibrio vulnificus.
- Halophilic: grow with salt and on TCBS agar.
- V. vulnificus in wounds causes very rapidly spreading necrotising fasciitis.
- Doxycycline plus ceftriaxone and early surgery in severe infection.

## At a glance

**Gram**
Gram-negative

**Shape**
Curved (comma-shaped) rod

**Oxygen**
Facultative anaerobe

**Family**
Vibrionaceae

**Stain**
Curved, motile Gram-negative rods

## Morphology

- Curved rod with one polar flagellum
- Halophilic: needs salt to grow
- Oxidase positive; grows on TCBS agar

## Transmission

- Eating raw or undercooked shellfish, above all oysters
- Wounds exposed to salt or brackish water, or to raw seafood
- Not spread from person to person

**Reservoir:** Warm salty and brackish coastal waters; more abundant in the hot months

### Isolation precautions

What the care team adds to standard precautions.

- Standard

## Virulence factors

- V. vulnificus: polysaccharide capsule that blocks phagocytosis
- Toxins and enzymes that destroy tissue and cause bullae and necrosis
- Free iron boosts its growth, so cirrhosis and haemochromatosis raise the risk
- V. parahaemolyticus: haemolysins that damage the intestinal epithelium

## Diseases it causes

- Primary septicaemia from V. vulnificus after eating raw oysters [Sepsis and septic shock →](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- Seafood-associated gastroenteritis (mostly V. parahaemolyticus) [Acute (viral) gastroenteritis →](https://durgical.com/en/conditions/acute-gastroenteritis/)
- Wound infection with necrotising fasciitis from V. vulnificus

## Clinical picture

- Fever, shock and haemorrhagic bullae on the legs in a person with cirrhosis
- Watery diarrhoea with cramps after eating shellfish
- Wound infection progresses within hours; amputation may be needed

## Diagnosis

- Blood culture and culture of bulla fluid or the wound
- Stool culture on TCBS agar: tell the laboratory if Vibrio is suspected
- A history of raw shellfish or seawater is the key clue

## Treatment

Severe V. vulnificus infection: tetracyclines (doxycycline) together with a third-generation cephalosporin (ceftriaxone), or a fluoroquinolone, plus urgent surgical debridement. Mild gastroenteritis usually settles with hydration.

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

In Pharmacology:

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

## Prevention

- Avoid raw oysters and shellfish, above all with liver disease or immunosuppression
- Cover wounds or stay out of the sea with open wounds
- Wash hands and surfaces after handling raw seafood

## Memory aid

"Vulnificus wounds": the vibrio that wounds the skin and attacks the sick liver; parahaemolyticus stays in the gut.

## Test yourself

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

## Which patient is at highest risk of Vibrio vulnificus septicaemia?

Someone with chronic liver disease such as cirrhosis, or with iron overload, who eats raw oysters.

## Which selective culture medium is used for vibrios?

TCBS agar (thiosulfate-citrate-bile salts-sucrose).

## Which severe skin infection can V. vulnificus cause?

A wound infection with bullae and necrotising fasciitis that progresses within hours.

## Which non-cholera vibrio most often causes seafood gastroenteritis?

Vibrio parahaemolyticus.

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

## Related

- [Vibrio cholerae](https://durgical.com/en/microbiology/vibrio-cholerae/)
- [Pseudomonas aeruginosa](https://durgical.com/en/microbiology/pseudomonas-aeruginosa/)

## Related conditions

- [Sepsis and septic shock](https://durgical.com/en/conditions/sepsis-and-septic-shock/)
- [Acute (viral) gastroenteritis](https://durgical.com/en/conditions/acute-gastroenteritis/)

## 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.

[← Back to the group: Other clinically important bacteria](https://durgical.com/en/microbiology/groups/other-clinically-important-bacteria/)

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

Sources: [About Vibrio Infection | Vibrio Infection | CDC](https://www.cdc.gov/vibrio/about/index.html) (CDC, 2024); Jawetz, Melnick & Adelberg's Medical Microbiology, 26th ed., chapter 17: Vibrios, Campylobacters, Helicobacter, and Associated Bacteria (McGraw-Hill, 2013).

## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake

Representative model, for educational purposes only.

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