What is the treatment for a patient with a positive Clostridioides difficile (C diff) stool test?

Treatment for Positive C. difficile Stool Test

For patients with a positive C. difficile stool test, treatment should be based on disease severity, with oral vancomycin 125 mg four times daily for 10 days for severe cases and oral metronidazole 500 mg three times daily for 10 days for non-severe cases. 1

Disease Severity Assessment

Before initiating treatment, assess the severity of C. difficile infection (CDI):

Non-severe CDI (all criteria must be met):

• Stool frequency < 4 times daily 1
• No signs of severe colitis 1
• White blood cell count < 15 × 10^9/L 1

Severe CDI (any of the following):

• Fever (core body temperature > 38.5°C) 1
• Rigors (uncontrollable shaking with fever) 1
• Hemodynamic instability or signs of septic shock 1
• Signs of peritonitis (decreased bowel sounds, abdominal tenderness) 1
• Ileus (vomiting, absent passage of stool) 1
• Marked leukocytosis (WBC > 15 × 10^9/L) 1
• Rise in serum creatinine (>50% above baseline) 1
• Elevated serum lactate 1
• Pseudomembranous colitis on endoscopy 1

Treatment Algorithm

Initial Episode Treatment:

1. If oral therapy is possible:

   • Non-severe CDI: Metronidazole 500 mg three times daily orally for 10 days 1
   • Severe CDI: Vancomycin 125 mg four times daily orally for 10 days 1

2. If oral therapy is impossible:

   • Non-severe CDI: Metronidazole 500 mg three times daily intravenously for 10 days 1
   • Severe CDI: Metronidazole 500 mg three times daily intravenously for 10 days PLUS intracolonic vancomycin 500 mg in 100 mL normal saline every 4-12 hours and/or vancomycin 500 mg four times daily by nasogastric tube 1

3. For mild CDI clearly induced by antibiotics:

   • Consider stopping the inducing antibiotic and observe closely 1
   • Initiate therapy immediately if clinical deterioration occurs 1

First Recurrence Treatment:

• Same as initial episode treatment 1

Second or Subsequent Recurrence Treatment:

• If oral therapy is possible:

  • Vancomycin 125 mg four times daily orally for at least 10 days 1
  • Consider a tapered/pulsed vancomycin regimen (decreasing daily dose with 125 mg every 3 days or a dose of 125 mg every 3 days for 3 weeks) 1
  • Alternative: Fidaxomicin 200 mg twice daily for 10 days 1

• If oral therapy is impossible:

  • Metronidazole 500 mg three times daily intravenously for 10-14 days plus retention enema of vancomycin 500 mg in 100 mL normal saline every 4-12 hours and/or vancomycin 500 mg four times daily by nasogastric tube 1

Special Considerations

Fidaxomicin

• May be particularly useful for patients at higher risk for recurrence (elderly patients or those receiving concomitant antibiotics) 1, 2
• Associated with significantly lower recurrence rates compared to vancomycin (15.4% vs. 25.3%) 2, 3
• FDA-approved for adults and pediatric patients aged 6 months and older 4

Surgical Intervention

• Colectomy should be considered for:
  • Perforation of the colon 1
  • Systemic inflammation and deteriorating clinical condition not responding to antibiotic therapy 1
  • Toxic megacolon or severe ileus 1
  • Consider surgery before serum lactate exceeds 5.0 mmol/L 1

Additional Management Points

• Avoid antiperistaltic agents and opiates 1
• Discontinue proton pump inhibitors if not medically necessary 5
• If other antibiotics must be continued, use those less frequently implicated with CDI 5
• Vancomycin achieves high fecal concentrations (>2000 mg/L), which are 3 orders of magnitude higher than the MIC90 against C. difficile 6

Treatment Response Monitoring

• Successful response: Decreased stool frequency or improved stool consistency after 3 days and no new signs of severe colitis 1
• Treatment failure: Absence of treatment response 1
• Recurrence: Increased stool frequency for two consecutive days with looser stools or new signs of severe colitis, plus microbiological evidence of toxin-producing C. difficile 1

Clinical success rates with vancomycin treatment are approximately 81% 7, with median time to resolution of diarrhea of 4-5 days 7.