Trimethoprim/sulfamethoxazole-associated pseudomembranous colitis

Area of Science:

• Infectious Diseases
• Gastroenterology
• Pharmacology

Background:

• Urinary tract infections (UTIs) are common and often treated with antibiotics.
• Trimethoprim/sulfamethoxazole (TMP/SMX) is a frequently prescribed antibiotic for UTIs.
• Antibiotic-associated colitis is a known, albeit infrequent, complication of antibiotic therapy.

Observation:

• A patient undergoing treatment for a UTI with TMP/SMX developed pseudomembranous colitis.
• Proctosigmoidoscopy revealed characteristic pseudomembranes.
• Stool cultures confirmed Clostridium difficile as the causative pathogen.

Findings:

• TMP/SMX can induce pseudomembranous colitis.
• Clostridium difficile is the identified organism responsible for this adverse reaction.
• The patient's condition resolved with oral vancomycin therapy.

Implications:

• This case highlights an infrequent but serious adverse reaction to TMP/SMX.
• Early recognition and appropriate treatment (e.g., vancomycin) are crucial for managing TMP/SMX-associated C. difficile colitis.
• Clinicians should consider this diagnosis in patients with diarrhea during or after TMP/SMX treatment.