What are the appropriate antibiotics for treating colitis?

Antibiotic Treatment for Colitis

For colitis treatment, metronidazole 500 mg three times daily orally for 10 days is recommended for non-severe Clostridioides difficile colitis, while vancomycin 125 mg four times daily orally for 10 days is recommended for severe C. difficile colitis. 1, 2, 3

Antibiotic Selection Based on Colitis Type

Clostridioides difficile Colitis

• For non-severe C. difficile colitis: metronidazole 500 mg three times daily orally for 10 days 1, 2, 3
• For severe C. difficile colitis: vancomycin 125 mg four times daily orally for 10 days 1, 2, 3
• For recurrent C. difficile colitis: vancomycin 125 mg four times daily orally for at least 10 days, with consideration of taper/pulse strategy (decreasing daily dose with 125 mg every 3 days or a dose of 125 mg every 3 days for 3 weeks) 1, 2
• Teicoplanin 100 mg twice daily can be used as an alternative to oral vancomycin if available 1, 2
• Fidaxomicin 200 mg twice daily for 10 days is an option for recurrent C. difficile infection 2

When Oral Therapy is Not Possible

• For non-severe C. difficile colitis: metronidazole 500 mg three times daily intravenously for 10 days 1
• For severe C. difficile colitis: metronidazole 500 mg three times daily intravenously for 10 days PLUS intracolonic vancomycin 500 mg in 100 mL of normal saline every 4-12 hours and/or vancomycin 500 mg four times daily by nasogastric tube 1

Staphylococcal Enterocolitis

• Total daily dosage of vancomycin 500 mg to 2 g administered orally in 3 or 4 divided doses for 7 to 10 days 4

Inflammatory Bowel Disease (Ulcerative Colitis)

• No antibiotic regimen is generally recommended for ulcerative colitis according to guidelines 2
• Limited research suggests a combination of antibiotics (metronidazole, amoxicillin, doxycycline, and sometimes vancomycin) may be effective in refractory pediatric ulcerative colitis cases, but this remains investigational 5

Severity Assessment for C. difficile Colitis

Non-severe C. difficile colitis criteria:

• Stool frequency < 4 times daily 1
• No signs of severe colitis 1
• White blood cell count < 15 × 10^9/L 3

Severe C. difficile colitis criteria:

• Fever, rigors, hemodynamic instability 2
• Marked leukocytosis (leukocyte count > 15 × 10^9/L) 1
• Marked left shift (band neutrophils > 20% of leukocytes) 1
• Rise in serum creatinine (>50% above baseline) 1
• Elevated serum lactate 1
• Pseudomembranous colitis on endoscopy 1
• Imaging findings: distension of large intestine, colonic wall thickening, pericolonic fat stranding, or ascites not explained by other causes 1

Important Considerations and Pitfalls

• Antiperistaltic agents and opiates should be avoided in C. difficile infection 1, 3
• The inciting antibiotic should be discontinued if possible 1, 3
• Mild C. difficile colitis clearly induced by antibiotics may be treated by stopping the inducing antibiotic, but patients should be observed closely for clinical deterioration 1
• Colectomy should be considered for perforation of the colon, systemic inflammation with deteriorating clinical condition not responding to antibiotics, toxic megacolon, or severe ileus 1, 3
• Recurrence of C. difficile occurs in up to 20% of cases and is associated with persistence of C. difficile in the stools 6
• Vancomycin use should be limited to decrease the development of vancomycin-resistant organisms 6
• For patients >65 years of age, renal function should be monitored during and following treatment with vancomycin to detect potential nephrotoxicity 4
• Severe dermatologic reactions including toxic epidermal necrolysis, Stevens-Johnson syndrome, and drug reaction with eosinophilia and systemic symptoms have been reported with vancomycin use 4

Treatment Response and Failure

Treatment response criteria:

• Stool frequency decreases or stool consistency improves after 3 days 1
• No new signs of severe colitis develop 1

Treatment failure:

• Absence of treatment response as defined above 1

Recurrence criteria:

• Stool frequency increases for two consecutive days and stools become looser or new signs of severe colitis develop 1
• Microbiological evidence of toxin-producing C. difficile in stools without evidence of another cause of diarrhea after an initial treatment response 1