Clostridium difficile Infection

C. difficile Summary

Key Facts

20-30% of antibiotic-associated diarrhoea
Spore-forming anaerobic bacterium
Hospital-acquired infection
Recurrence risk: 20% after first episode

First-line Treatment

Vancomycin: 125mg QDS × 10 days
Fidaxomicin: 200mg BD × 10 days (2nd line)
Stop causative antibiotics
Review PPIs

Severity Assessment

Mild: <3 stools/day, normal WCC
Moderate: 3-5 stools/day, WCC <15
Severe: WCC >15, creatinine >50%↑
Life-threatening: Hypotension, ileus

Investigations

Stool for C. difficile toxin
FBC, U&E, creatinine
No test of cure
No repeat testing same episode

High-Risk Groups

Age >65 years
Recent antibiotics
PPI use
Hospitalization
Immunosuppression

Key fact: Around 20–30% of cases of antibiotic-associated diarrhoea are due to Clostridium difficile.

Risk Factors

Demographic Factors

Increased age (> 65 years)
Prolonged hospitalisation
Nursing home residence

Medication Factors

Recent antibiotic treatment
Proton pump inhibitor use
Multiple antibiotic courses

Medical Conditions

Chronic renal disease
Inflammatory bowel disease
Immunosuppression
Abdominal surgery

High-Risk Antibiotics

Clindamycin - highest risk
Cephalosporins (especially 3rd/4th generation)
Fluoroquinolones
Broad-spectrum penicillins

Recurrence Risk

20% after first episode
60% after multiple recurrences
Higher risk with continued antibiotic exposure

Severity Assessment

Severity of Clostridium difficile infection can be defined as:

Severity	Clinical Features	Management
Mild	<3 loose stools per day Normal white cell count No systemic features	Vancomycin 125mg QDS × 10 days
Moderate	3–5 loose stools per day WCC < 15 × 10⁹/L Mild systemic symptoms	Vancomycin 125mg QDS × 10 days
Severe	WCC > 15 × 10⁹/L Creatinine >50% above baseline Temperature >38.5°C Severe colitis signs	Vancomycin 125mg QDS × 10 days
Life-threatening	Hypotension/shock Ileus or toxic megacolon CT evidence of severe disease Peritonitis signs	Vancomycin 500mg QDS + IV Metronidazole Urgent surgical review

Investigations

For adults with suspected Clostridium difficile infection:

Send a stool sample to test for C. difficile infection if the person is symptomatic with liquid/loose stools (with a consistency that takes the shape of the container — ideally 1/4 filled) that is not clearly attributable to another condition or therapy, and C. difficile infection is suspected, for example if the person:
- Has been in contact with a person with C. difficile infection.
- Has recently had a course of antibiotics, proton-pump inhibitor treatment, or been in hospital.
Do not wait to initiate sampling or testing as any delay may increase the severity of the disease and the risk of C. difficile transmission.
Ensure the following details are stated on the request form:
- Clinical features (for example nature and duration of symptoms).
- Recent antibiotic or proton pump inhibitor, or hospital admission.
- Contact with other affected individuals or outbreak.
- Underlying illness.
- State if the test was requested by the Health Protection Team, a Consultant in Communicable Disease Control, or a Consultant in Health Protection.
Check the full blood count and serum creatinine in order to help assess the severity of C. difficile.
Consider re-testing if the first test is negative and there is a strong clinical suspicion of C. difficile infection — seek advice from a consultant medical microbiologist or infection control doctor.
Do not retest people with a positive C. difficile infection if they are still symptomatic within the same episode. Only retest to confirm recurrent C. difficile infection if the symptoms resolve and then recur.
Do not test to confirm cure.

Testing Guidelines

Test: Liquid stools in high-risk patients
Do not test: Formed stools or asymptomatic patients
No test of cure: Do not repeat testing after treatment
Re-test only if: Symptoms resolve then recur

Management

Immediate Actions

Stop causative antibiotics
Review PPI necessity
Isolation precautions
Hand hygiene (soap and water)

First Episode

Vancomycin: 125mg QDS × 10 days
Alternative: Fidaxomicin 200mg BD × 10 days
Avoid antimotility drugs
Fluid management

Severe Cases

Vancomycin 500mg QDS × 10 days
IV Metronidazole 500mg TDS × 10 days
Urgent surgical review
ICU monitoring if needed

Infection Control

Contact precautions: Gloves and aprons
Hand hygiene: Soap and water (alcohol gels ineffective against spores)
Environmental cleaning: Chlorine-based disinfectants
Isolation: Single room if possible

Complications

Gastrointestinal

Pseudomembranous colitis
Toxic megacolon
Colonic perforation
Paralytic ileus

Systemic

Sepsis
Dehydration
Electrolyte imbalances
Renal impairment

Long-term

Recurrent infection (20-60%)
Chronic diarrhoea
Malabsorption
Death (1-2% overall)