American Board of Internal Medicine (ABIM) Certification Practice Exam

Which is a correct course of action for a CAP patient with risk factors for Pseudomonas aeruginosa?

1. Macrolide plus glucocorticoid

2. Antipseudomonal β-lactam with a respiratory fluoroquinolone

3. Start SABA and observe

4. Doxycycline plus β-lactam

The correct answer is: Antipseudomonal β-lactam with a respiratory fluoroquinolone

In managing a community-acquired pneumonia (CAP) patient who has risk factors for Pseudomonas aeruginosa, selecting an antipseudomonal β-lactam in combination with a respiratory fluoroquinolone represents a targeted and effective approach. Pseudomonas aeruginosa is a gram-negative bacterium that can lead to serious respiratory infections, particularly in patients with certain risk factors, including prior antibiotic use, chronic lung disease, or hospitalization. The rationale for using an antipseudomonal β-lactam, such as piperacillin-tazobactam or cefepime, stems from their efficacy against Pseudomonas and their ability to penetrate into the lung tissues effectively. Pairing this with a respiratory fluoroquinolone, such as levofloxacin or moxifloxacin, provides additional coverage, particularly for atypical pathogens and offers a dual mechanism of action against the bacteria involved in pneumonia. The combination is particularly beneficial in critically ill patients or those with significant comorbidities where mortality risk can be higher. In summary, this dual therapy strategy ensures appropriate coverage for the resistant organism, aligns with current guidelines for treating pneumonia in at-risk populations, and maximizes the chance of a favorable