American Board of Internal Medicine (ABIM) Certification Practice Exam

For a patient with drug-resistant S. pneumoniae pneumonia, what combinational treatment could be provided?

1. Levofloxacin alone

2. Antipseudomonal β-lactam plus an aminoglycoside plus a macrolide

3. Doxycycline and azithromycin

4. High dose IG plus oral glucocorticoid

The correct answer is: Antipseudomonal β-lactam plus an aminoglycoside plus a macrolide

For a patient with drug-resistant Streptococcus pneumoniae pneumonia, the correct combinational treatment involves using an antipseudomonal β-lactam, an aminoglycoside, and a macrolide. This combination is effective because it employs multiple mechanisms of action and provides broad-spectrum coverage against resistant organisms. The antipseudomonal β-lactam, such as piperacillin-tazobactam or cefepime, targets the bacterial cell wall and is effective against a wide range of Gram-positive and Gram-negative bacteria. The aminoglycoside adds another layer of efficacy, particularly against aerobic Gram-negative bacilli, while also increasing the overall bacterial killing effect through synergistic action. The macrolide, on the other hand, enhances coverage against atypical pathogens and adds further anti-inflammatory properties, crucial in managing pneumonia. This combinatorial strategy is particularly important in cases of drug-resistant pathogens, as it maximizes the chance of effective treatment while minimizing the risk of treatment failure. Other treatment options, like those listed in the other choices, do not provide the necessary breadth and depth of coverage against drug-resistant strains of S. pneumoniae, which is essential in such clinical scenarios.