Bacterial Infections USMLE Step 1 Practice Question
A 58 year old man with a history of splenectomy after trauma presents with fever, productive cough, and pleuritic chest pain. Temperature is 39 C (102.2 F). Chest radiograph shows right lower lobe consolidation. Blood cultures grow alpha hemolytic gram positive diplococci that are optochin sensitive and bile soluble. Which of the following best explains this patient’s increased susceptibility to severe infection with this organism?
Answer choices
- AReduced T cell mediated macrophage activation
- BLoss of mucosal IgA secretion
- CDecreased interferon gamma production by NK cells
- DDefective neutrophil oxidative burst
- EImpaired clearance of opsonized encapsulated bacteriaCorrect answer
- FInability to produce mannose-binding lectin in response to infection
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