[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Microbiology](https://durgical.com/en/microbiology/) › [Gram-positive rods](https://durgical.com/en/microbiology/groups/gram-positive-rods/) › Clostridioides difficile

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

# Clostridioides difficile

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

A bacterium that causes diarrhoea and colitis, mostly after antibiotics; its spores resist alcohol and are removed by washing with soap and water.

Updated 2026-11-01

Also called: C. diff, Clostridium difficile (former name)

## Key points

- Recent antibiotic + diarrhoea = think C. difficile.
- Toxins A and B; pseudomembranes on colonoscopy.
- Oral vancomycin or fidaxomicin; metronidazole is no longer first line.
- NCLEX: contact precautions and soap-and-water handwashing, not alcohol.
- Sporicidal disinfectant for the room.

## At a glance

**Gram**
Gram-positive

**Shape**
Rod with a subterminal spore

**Oxygen**
Obligate anaerobe

**Family**
Peptostreptococcaceae

**Stain**
Gram positive; spore former

## Morphology

- Large Gram-positive rod
- Spores that survive months or years on surfaces
- Toxigenic (toxins A and B) and non-toxigenic strains

## Transmission

- Faecal-oral: spores on surfaces, hands and objects
- Contact with infected patients in hospitals and nursing homes
- Antibiotics disturb the microbiota and let the bacterium take over

### 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

- Toxin A (enterotoxin) and toxin B (cytotoxin): inactivate Rho GTPases in colon cells
- Epithelial damage, inflammation and pseudomembranes
- Spores: environmental persistence and relapses
- Hypervirulent strains with higher toxin output

## Diseases it causes

- C. difficile colitis, from diarrhoea to pseudomembranous colitis and toxic megacolon [Clostridioides difficile infection →](https://durgical.com/en/conditions/clostridioides-difficile-infection/)

## Clinical picture

- Watery diarrhoea during or weeks after an antibiotic
- Fever, abdominal pain and leucocytosis
- Severe forms: ileus, toxic megacolon, sepsis

## Diagnosis

- Only unformed stool from symptomatic patients is tested
- Stool detection of the toxins or their genes (PCR)
- Colonoscopy: yellowish pseudomembranes
- No test of cure: many patients stay colonised

## Treatment

Stop the inciting antibiotic when possible. Oral vancomycin or fidaxomicin are preferred; metronidazole is now an alternative. Faecal microbiota transplant is used for multiple recurrences. Fulminant cases may need surgery.

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

In Pharmacology:

- [Vancomycin](https://durgical.com/en/pharmacology/vancomycin/)

## Prevention

- Antibiotic stewardship
- Hand hygiene with soap and water: alcohol gel does not kill spores
- Contact precautions: gown and gloves, single room
- Cleaning with sporicidal disinfectants (for example, chlorine-based)
- Dedicated patient equipment

## Memory aid

C. difficile spores laugh at alcohol: difficult to remove, they only go with soap, water and friction.

## Test yourself

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

## Why is alcohol gel not enough for hand hygiene against C. difficile?

Because it does not kill the spores; soap-and-water washing removes them mechanically.

## Which isolation precautions does a patient with C. difficile diarrhoea need?

Standard plus contact precautions: gown, gloves, single room and dedicated equipment.

## Which drugs are preferred against C. difficile?

Oral vancomycin or fidaxomicin.

## Which endoscopic finding is classic for severe C. difficile colitis?

Pseudomembranes: yellowish plaques stuck to the colonic mucosa.

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

## Related

- [Clostridium perfringens](https://durgical.com/en/microbiology/clostridium-perfringens/)
- [Enterococcus](https://durgical.com/en/microbiology/enterococcus/)

## Related conditions

- [Clostridioides difficile infection](https://durgical.com/en/conditions/clostridioides-difficile-infection/)

## 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: Gram-positive rods](https://durgical.com/en/microbiology/groups/gram-positive-rods/)

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

Sources: [About C. diff](https://www.cdc.gov/c-diff/about/index.html) (CDC, 2024); [C. diff: Facts for Clinicians](https://www.cdc.gov/c-diff/hcp/clinical-overview/index.html) (CDC, 2024).

## **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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