Clostridioides difficile Infection
System: Gastrointestinal Infections · Parent MOC: MOC - Diseases by System
One-Sentence Definition
Antibiotic-associated colitis caused by toxin-producing C. difficile spores that germinate when gut Normal Microbiota is disrupted.
Clinical Presentation
- Watery diarrhea (≥3 stools/day), abdominal pain, fever, leukocytosis after antibiotics/healthcare exposure
- Severe: shock, ileus, megacolon — surgical emergency spectrum
- Recurrence common
Pathogens
| Agent | Notes |
|---|---|
| Clostridioides difficile (TBD organism page) | Anaerobic spore-former — Bacterial Endospore |
| Toxins A/B | Cause epithelial injury |
Pathogenesis
- Spores survive environment/alcohol hand gel poorly vs soap — infection control nuance
- Antibiotics ↓ colonization resistance → germination → toxin → colitis
- Fecal microbiota concepts for recurrence
Diagnosis
| Step | Test | Note |
|---|---|---|
| Only if diarrhea (or ileus) | Stool NAAT ± toxin EIA algorithms | Don’t test formed stool |
| Imaging | CT if severe / complications | Toxic megacolon |
Lab algorithms (GDH/toxin/NAAT) vary — know your hospital’s pathway.
Treatment Principles
- Stop culprit antibiotic if possible
- First-line agents per severity (fidaxomicin / vancomycin — guideline era)
- Fulminant: high-dose vancomycin ± IV metronidazole + surgical consult
- Recurrence: pulsed/tapered regimens, bezlotoxumab selected, FMT in multiply recurrent
Prevention
- Stewardship (esp. fluoroquinolones, clinda, broad β-lactams)
- Contact precautions; soap & water handwashing; sporicidal cleaning
- Avoid unnecessary PPI when possible (association debated/contextual)
Differential / Pitfalls
- Other infectious diarrhea, ischemic colitis, laxatives
- PCR+ without toxin/clinical disease = colonization
Learning Aids
Clinical Example
Example
Case: Week of ciprofloxacin for UTI → profuse watery diarrhea, WBC 22k.
Question: Mechanism link to microbiota and first management moves?
Answer: Antibiotics collapsed Normal Microbiota → C. difficile toxins. Isolate patient, stool testing per algorithm, start CDI therapy, stop culprit abx if feasible, infection control for spores.
Related
- Gastrointestinal Infections · Bacterial Endospore · Normal Microbiota
- MOC - Antimicrobials (stewardship)
Active Recall
- Why alcohol hand rub is insufficient for C. difficile spores?
- When should you not order CDI testing?
- Role of FMT?