Streptococcus pneumoniae Quiz: Ace Your Exams

A 65-year-old man comes to the emergency department for evaluation of three days of dyspnea, fever, and cough. Past medical history is significant for gastroesophageal reflux disease, dyslipidemia, HIV, and two episodes of Pneumocystis carinii pneumonia. The patient is compliant with antiretroviral therapy and his last CD4 count was 250 cells/microL. Current medications include tenofovir-emtricitabine and dolutegravir, atorvastatin, and aspirin. The patient is sexually active with men and women and uses condoms consistently. The patient does not use intravenous drugs, alcohol, or tobacco. The patient owns two parrots and a cat. Temperature is 38.11°C (100.0°F), pulse is 100/min, respirations are 20/min, and blood pressure is 130/75 mmHg, SpO2 is 92% on room air. Physical examination reveals anterior and posterior cervical lymphadenopathy as well as rales over the right anterior and posterior chest. A Chest x-ray is depicted below. Which of the following is the most likely organism implicated in this patient's current clinical condition?
 
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