What are the antibiotic treatment options for infectious colitis?

Antibiotic Treatment Options for Infectious Colitis

For infectious colitis, the first-line antibiotic treatment depends on the specific pathogen, with metronidazole recommended for mild-to-moderate C. difficile colitis and vancomycin recommended for severe C. difficile colitis. 1, 2

Clostridium difficile-Associated Colitis

Disease Severity Assessment

• Assess disease severity to guide treatment choice 3, 2
• Non-severe CDI: stool frequency <4 times daily, no signs of severe colitis, WBC <15×10^9/L 1, 2
• Severe CDI: fever, rigors, hemodynamic instability, peritonitis, ileus, marked leukocytosis, elevated creatinine/lactate, pseudomembranous colitis 1, 2

Treatment Algorithm

1. Initial episode and first recurrence:

   • Non-severe CDI: Metronidazole 500 mg orally three times daily for 10 days 1, 2
   • Severe CDI: Vancomycin 125 mg orally four times daily for 10 days 1, 2
   • If oral therapy impossible:
     • Non-severe: Metronidazole 500 mg IV three times daily for 10 days 1
     • Severe: Metronidazole 500 mg IV three times daily PLUS intracolonic vancomycin 500 mg in 100 mL normal saline every 4-12 hours 1, 2

2. Second or subsequent recurrences:

   • Vancomycin 125 mg orally four times daily for at least 10 days 1, 2
   • Consider vancomycin taper/pulse strategy (decreasing daily dose with 125 mg every 3 days or a dose every 3 days for 3 weeks) 1
   • Fidaxomicin 200 mg twice daily for 10 days may be useful for patients at high risk for recurrence 1, 3
   • Teicoplanin 100 mg twice daily can replace oral vancomycin if available 1, 2

3. Advanced interventions:

   • Fecal microbiota transplantation for multiple recurrences that have failed appropriate antibiotic treatments 1
   • Bezlotoxumab (monoclonal antibody) may prevent recurrences, particularly in immunocompromised patients and severe CDI 1
   • Colectomy for perforation, systemic inflammation not responding to antibiotics, toxic megacolon, or severe ileus 1, 2

Important Considerations

• Discontinue the inciting antibiotic if possible 1, 2
• Avoid antiperistaltic agents and opiates 1, 2
• Consider discontinuing proton pump inhibitors if not medically necessary 1, 3
• Implement infection control measures: private room, hand hygiene with soap and water, contact precautions 1

Other Bacterial Causes of Infectious Colitis

• For febrile dysenteric diarrhea caused by invasive bacterial enteropathogens (Shigella, Salmonella, Campylobacter): Azithromycin 1000 mg as a single dose 4
• For empiric treatment when specific pathogen is unknown: obtain stool culture before initiating antimicrobial therapy 4, 5
• For suspected Shiga toxin-producing E. coli (STEC): avoid antibiotics as they may increase risk of hemolytic uremic syndrome 4

Inflammatory Bowel Disease-Associated Colitis

• Antibiotics are not first-line therapy for ulcerative colitis 2, 6
• For Crohn's disease with suppurative complications (abscesses, fistulas): ciprofloxacin, metronidazole, or combination of both 6
• Rifaximin has shown promising results for active luminal Crohn's disease 6

Pitfalls and Caveats

• Vancomycin must be given orally for C. difficile colitis; parenteral administration is not effective for this indication 7
• Almost all antibiotics can potentially cause C. difficile colitis, including vancomycin and metronidazole when used parenterally 8
• Relapses occur in 5-50% of treated patients 8
• Monitor renal function in patients >65 years receiving oral vancomycin, as nephrotoxicity can occur 7
• Severe dermatologic reactions including toxic epidermal necrolysis and Stevens-Johnson syndrome have been reported with vancomycin use 7