American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended treatment for diarrhea caused by Yersinia?

1. Trimethoprim-sulfamethoxazole × 5 days

2. Fluoroquinolone × 3 days; trimethoprim-sulfamethoxazole × 3 days

3. Ciprofloxacin × 1 dose

4. Metronidazole × 3 days

The correct answer is: Fluoroquinolone × 3 days; trimethoprim-sulfamethoxazole × 3 days

The recommended treatment for diarrhea caused by Yersinia is a combination of fluoroquinolones and trimethoprim-sulfamethoxazole, typically for a duration of 3 days for each medication. This approach is effective due to the sensitivity of Yersinia species to these antibiotics, providing a broad spectrum antimicrobial effect that can target the bacteria effectively. Yersinia enterocolitica, the species commonly associated with gastrointestinal illnesses, can often be serious, leading to a more complex clinical picture. Therefore, the use of both classes of antibiotics helps ensure effective treatment, especially in cases that may be more severe or in immunocompromised patients. While fluoroquinolones, such as ciprofloxacin, can treat Yersinia infections efficiently on their own, the addition of trimethoprim-sulfamethoxazole enhances coverage, which is especially prudent in critical cases. Other treatment options listed may lack the broad-spectrum efficacy or the recommended treatment duration for managing an infection caused by Yersinia effectively. The use of a single dose of ciprofloxacin would likely be inadequate, as a comprehensive treatment regimen is typically necessary to clear the infection. Similarly, options that rely solely on metronidazole or shorter course treatments