American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended treatment regimen for a patient with HIV/AIDS and disseminated Mycobacterium avium complex infection?

1. Rifampin and isoniazid

2. Clarithromycin, ethambutol, and rifabutin

3. Vancomycin and azithromycin

4. Ciprofloxacin and meropenem

The correct answer is: Clarithromycin, ethambutol, and rifabutin

The recommended treatment regimen for a patient with HIV/AIDS and disseminated Mycobacterium avium complex (MAC) infection includes clarithromycin, ethambutol, and rifabutin. This combination is effective due to the individual roles of each drug in targeting the MAC bacteria, which can cause serious disseminated infections, particularly in immunocompromised individuals. Clarithromycin is a macrolide antibiotic that effectively inhibits protein synthesis in Mycobacterium avium, making it a cornerstone of MAC therapy. Ethambutol is included to prevent the development of resistance, as it acts by inhibiting the synthesis of the bacterial cell wall. Rifabutin, a rifamycin antibiotic, enhances the overall efficacy of the regimen and also plays a critical role in preventing resistance. This treatment approach is particularly important for patients with HIV/AIDS, who often present with low CD4 counts and are at high risk for MAC infections. The combination of these three medications not only targets the infection effectively but also helps reduce the likelihood of resistance development, promoting better long-term outcomes. The other options listed do not provide appropriate coverage for Mycobacterium avium. Rifampin and isoniazid are primarily used for tuberculosis, vancomycin