Pneumonia USMLE Step 1 Practice Question
A 17-year-old girl with cystic fibrosis presents with a 3-day history of increased productive cough, fever, and declining pulmonary function. Vital signs show temperature 38.5°C, heart rate 102/min, respiratory rate 22/min, blood pressure 118/74 mmHg, and SpO2 92% on room air. Sputum culture yields an oxidase-positive, non-lactose-fermenting gram-negative rod producing blue-green pigment. Chest X-ray reveals new bronchial wall thickening. She denies hemoptysis. Which organism is most likely responsible for this infection?
Answer choices
- APseudomonas aeruginosaCorrect answer
- BStreptococcus pneumoniae
- CMycoplasma pneumoniae
- DKlebsiella pneumoniae
- EStaphylococcus aureus pneumonia
- FBurkholderia cepacia
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