A 7-year-old girl is brought to the emergency department due to 2 days of fever, productive cough, and shortness of breath. Medical history is significant for recurrent lung infections and cystic fibrosis. Weight is at the 5th percentile. Temperature is 38.1 C (100.6 F), pulse is 104/min, and respirations are 30/min. Pulse oximetry is 86% on room air. Examination shows a thin girl with digital clubbing and a hyperexpanded chest. Diffuse wheezes and crackles are present bilaterally. The rest of the examination is unremarkable. Chest x-ray reveals hyperinflation, chronic interstitial changes, and an infiltrate in the right lower lobe. Gram stain of sputum shows gram-negative rods. Which of the following is the most likely cause of this patient's recurrent infections?

Question

A 7-year-old girl is brought to the emergency department due to 2 days of fever, productive cough, and shortness of breath.  Medical history is significant for recurrent lung infections and cystic fibrosis.  Weight is at the 5th percentile.  Temperature is 38.1 C (100.6 F), pulse is 104/min, and respirations are 30/min.  Pulse oximetry is 86% on room air.  Examination shows a thin girl with digital clubbing and a hyperexpanded chest.  Diffuse wheezes and crackles are present bilaterally.  The rest of the examination is unremarkable.  Chest x-ray reveals hyperinflation, chronic interstitial changes, and an infiltrate in the right lower lobe.  Gram stain of sputum shows gram-negative rods.  Which of the following is the most likely cause of this patient's recurrent infections?

Quizplus · Accepted Answer

Eductional Objective: Patients with cystic fibrosis have thick, viscous mucus that accumulates in the airways and promotes colonization of bacteria, particularly Pseudomonas.  This gram-negative rod can produce biofilms, which act as a protective matrix that allows bacterial macrocolonies to develop, causing persistent infection.

A 7-Year-Old Girl Is Brought to the Emergency Department Due