A 75-year-old man comes to the emergency department with fever, chills, dyspnea, and a productive cough. His symptoms began suddenly 2 days ago. He has been hospitalized on several occasions for exacerbations of chronic bronchitis. The patient has been advised to stop smoking but continues to smoke cigarettes. He drinks 6-10 beers daily. His temperature is 38.8°C (101.8°F), pulse is 110/min, respirations are 24/min, and blood pressure is 105/74 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 92%. Examination reveals crackles over the right upper lung. Sputum microscopy reveals encapsulated gram-negative bacilli. The bacteria grow pink, mucoid colonies on MacConkey agar. Which of the following organisms is the most likely cause of this patient's condition?

Question

A 75-year-old man comes to the emergency department with fever, chills, dyspnea, and a productive cough. His symptoms began suddenly 2 days ago. He has been hospitalized on several occasions for exacerbations of chronic bronchitis.  The patient has been advised to stop smoking but continues to smoke cigarettes.  He drinks 6-10 beers daily. His temperature is 38.8°C (101.8°F), pulse is 110/min, respirations are 24/min, and blood pressure is 105/74 mm Hg. Pulse oximetry on room air shows an oxygen saturation of 92%. Examination reveals crackles over the right upper lung. Sputum microscopy reveals encapsulated gram-negative bacilli.  The bacteria grow pink, mucoid colonies on MacConkey agar.  Which of the following organisms is the most likely cause of this patient's condition?

Quizplus · Accepted Answer

Eductional Objective: Klebsiella is an encapsulated, lactose-fermenting, gram-negative bacillus that appears mucoid in culture.  It causes pneumonia in individuals with impaired host defenses, especially patients with alcohol use disorder.  Klebsiella pneumonia is characterized by tissue necrosis and early abscess formation with production of thick, mucoid, blood-tinged sputum (currant jelly sputum).

A 75-Year-Old Man Comes to the Emergency Department with Fever