What are the recommended antibiotic treatments for Clostridium difficile and Shigella infections?

Antibiotic Treatment for Clostridium difficile and Shigella Infections

For Clostridium difficile infection, oral vancomycin 125 mg four times daily or fidaxomicin 200 mg twice daily for 10 days is the recommended first-line treatment, with therapy selection based on disease severity and recurrence risk. 1

Clostridium difficile Infection (CDI) Treatment

Initial CDI Episode Treatment Algorithm

Non-severe CDI (WBC ≤15,000 cells/mL and serum creatinine <1.5 mg/dL)

• First-line options:
  • Vancomycin 125 mg orally four times daily for 10 days 2, 1
  • Fidaxomicin 200 mg orally twice daily for 10 days 2, 1
• Alternative (if access to first-line agents is limited):
  • Metronidazole 500 mg orally three times daily for 10 days 2
  • Note: Metronidazole is no longer preferred due to lower efficacy and risk of neurotoxicity with prolonged use 1

Severe CDI (WBC >15,000 cells/mL or serum creatinine ≥1.5 mg/dL)

• Vancomycin 125 mg orally four times daily for 10 days 2
• Fidaxomicin 200 mg orally twice daily for 10 days 2
• Consider increasing vancomycin dosage to 500 mg four times daily, although studies show similar efficacy between 125 mg and 500 mg doses 2, 3

Fulminant CDI (hypotension, shock, ileus, or megacolon)

• Vancomycin 500 mg orally four times daily PLUS
• Metronidazole 500 mg intravenously every 8 hours 2, 1
• If ileus present: Add rectal vancomycin 500 mg in 100 mL normal saline every 6 hours as retention enema 2
• Early surgical consultation for possible colectomy 2

Recurrent CDI Treatment

First Recurrence

• Vancomycin 125 mg four times daily for 10 days as a tapered and pulsed regimen 2 OR
• Fidaxomicin 200 mg twice daily for 10 days 2, 4
  • Fidaxomicin has shown lower second recurrence rates (19.7%) compared to vancomycin (35.5%) 4

Multiple Recurrences (≥2)

• Vancomycin in a tapered and pulsed regimen (125-500 mg/day every 2-3 days for at least 3 weeks) 2 OR
• Vancomycin 125 mg four times daily for 10 days followed by rifaximin 400 mg three times daily for 20 days 2 OR
• Fidaxomicin 200 mg twice daily for 10 days 2 OR
• Fecal microbiota transplantation (after failure of appropriate antibiotic treatments) 2

Pediatric CDI Treatment

• Non-severe CDI: Vancomycin 10 mg/kg/dose (max 125 mg) orally four times daily OR metronidazole 7.5 mg/kg/dose (max 500 mg) orally three or four times daily for 10 days 2
• Severe CDI: Vancomycin 10 mg/kg/dose (max 500 mg) orally four times daily for 10 days 2

Important Clinical Considerations

• Discontinue the inciting antibiotic as soon as possible to reduce recurrence risk 1
• Avoid antiperistaltic agents and opiates as they may mask symptoms and worsen disease 1
• Monitor for treatment response within 3 days (decreased stool frequency, improved consistency) 1
• For patients with inflammatory bowel disorders or renal insufficiency receiving oral vancomycin, consider monitoring serum vancomycin levels due to potential systemic absorption 5
• Fidaxomicin persists in the gut longer than vancomycin (>20 days vs ~4 days), which may contribute to lower recurrence rates 6
• For patients with severe CDI, recent evidence suggests fidaxomicin may result in lower recurrence rates compared to vancomycin (6.8% vs 17.6%) 7

Shigella Infection Treatment

Note: The provided evidence does not contain information about Shigella treatment. Based on general medical knowledge:

• First-line treatment for Shigella infection in adults is typically ciprofloxacin 500 mg twice daily for 3-5 days or azithromycin 500 mg once daily for 3 days
• Alternative options include trimethoprim-sulfamethoxazole or ceftriaxone, depending on local resistance patterns
• Treatment should be guided by antimicrobial susceptibility testing due to increasing resistance