Bacterial Infections USMLE Step 1 Practice Question
A 65 year old man develops fever, dry cough, watery diarrhea, and confusion 5 days after staying at a hotel. Temperature is 39.2 C (102.6 F). Chest radiograph shows patchy unilateral infiltrates. Laboratory studies reveal hyponatremia. Sputum gram stain shows many neutrophils but no visible organisms. Which of the following is the most likely causative pathogen?
Answer choices
- AChlamydia trachomatis
- BMycoplasma pneumoniae
- CStreptococcus pneumoniae
- DLegionella pneumophilaCorrect answer
- EKlebsiella pneumoniae
- FCoxiella burnetii (Q fever)
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