Pneumonia USMLE Step 1 Practice Question
A 19-year-old college student presents with 4 days of low-grade fever, headache, dry cough, and malaise. Vital signs show temperature 38.2°C, heart rate 92/min, respiratory rate 18/min, blood pressure 118/76 mmHg, and SpO2 98% on room air. Chest radiograph reveals patchy interstitial infiltrates disproportionately severe compared to mild findings on auscultation. Laboratory studies show normal leukocyte count. Otoscopy demonstrates bullous myringitis. He denies recent antibiotic use. Which organism is most likely responsible?
Answer choices
- AChlamydophila psittaci
- BLegionella pneumophila
- CMycoplasma pneumoniaeCorrect answer
- DPseudomonas aeruginosa
- EStreptococcus pneumoniae
- FMycobacterium tuberculosis
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