Bacterial Infections USMLE Step 1 Practice Question
A 67-year-old man with severe COPD presents with increased sputum production, dyspnea, and wheezing. Vital signs show HR 102/min, RR 24/min, BP 138/86 mmHg, temperature 38.2°C, and SpO2 91% on room air. Sputum culture grows oxidase-positive, gram-negative diplococci. Chest X-ray shows no infiltrates. He denies recent hospitalization or antibiotic use. Which organism most likely caused this acute exacerbation?
Answer choices
- ANeisseria meningitidis
- BKingella kingae
- CHaemophilus ducreyi
- DBordetella pertussis
- EMoraxella catarrhalisCorrect answer
- FPseudomonas aeruginosa
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