American Board of Internal Medicine (ABIM) Certification Practice Exam

In treating CAP in a patient with comorbidities, what is an appropriate antibiotic choice?

1. Doxycycline only

2. Respiratory fluoroquinolone or β-lactam plus macrolide

3. Macrolide as monotherapy

4. High dose glucocorticoid therapy

The correct answer is: Respiratory fluoroquinolone or β-lactam plus macrolide

In the management of community-acquired pneumonia (CAP) in patients with comorbidities, the most effective approach involves using a combination of antibiotics to ensure comprehensive coverage against potential pathogens. The recommended choice of a respiratory fluoroquinolone or a β-lactam plus macrolide reflects current guidelines that prioritize broad-spectrum treatment in patients who may have atypical pathogens or higher risk factors due to their comorbidities. Using a respiratory fluoroquinolone, such as levofloxacin or moxifloxacin, provides excellent coverage for both typical and atypical organisms responsible for CAP. Alternatively, the combination of a β-lactam (like amoxicillin or ceftriaxone) with a macrolide (such as azithromycin or clarithromycin) also ensures good coverage for Streptococcus pneumoniae and atypical pathogens like Mycoplasma pneumoniae. This synergy enhances treatment efficacy and reduces the risk of treatment failure. The other options do not provide the appropriate breadth of coverage needed for a patient with comorbidities. Monotherapy with doxycycline or a macrolide does not adequately address the possible pathogens in this population. Meanwhile, high-dose glucocorticoid therapy is not indicated for uncomplicated pneumonia and