American Board of Internal Medicine (ABIM) Certification Practice Exam

Which treatment is recommended for mild-to-moderate cases of Babesiosis?

1. Clindamycin plus quinine

2. Atovaquone plus azithromycin

3. Trimethoprim-sulfamethoxazole

4. Metronidazole

The correct answer is: Atovaquone plus azithromycin

The recommended treatment for mild-to-moderate cases of Babesiosis is Atovaquone plus azithromycin. This combination works effectively against the protozoan parasites of the Babesia species, which are transmitted through tick bites. Atovaquone has a mechanism of action that disrupts the mitochondrial electron transport chain and inhibits nucleic acid and ATP synthesis in the Babesia organism. Azithromycin, on the other hand, is a macrolide antibiotic that inhibits protein synthesis. The synergy between these two drugs enhances the overall therapeutic effect, making this combination a safe and effective treatment for patients with mild to moderate infections. The other options, while effective for different conditions or severe forms of Babesiosis, do not represent the first-line treatment for mild-to-moderate cases. Clindamycin plus quinine is typically reserved for severe cases or those with complications, and other treatments like Trimethoprim-sulfamethoxazole or Metronidazole are not standard therapies for Babesiosis, as they are more suitable for other types of infections.