Pneumonia USMLE Step 1 Practice Question
A 66-year-old man presents with abrupt onset fever (39.2°C), pleuritic chest pain, and productive cough with rust-colored sputum. He denies recent antibiotic use. Vital signs show HR 102/min, RR 24/min, BP 138/88 mmHg, and SpO2 92% on room air. Examination reveals bronchial breath sounds over the right lower lobe. Chest radiograph demonstrates lobar consolidation. Blood cultures pending; sputum Gram stain shows gram-positive diplococci. Which organism is most likely responsible?
Answer choices
- ALegionella pneumophila
- BStreptococcus pneumoniaeCorrect answer
- CKlebsiella pneumoniae
- DChlamydophila psittaci
- EMycoplasma pneumoniae
- FHaemophilus influenzae
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