In cystic fibrosis, which organism is frequently found in the lungs?

Cystic fibrosis is a genetic disorder that primarily affects the lungs and digestive system by disrupting the transport of chloride and sodium ions, leading to thick, viscous mucus production. This thick mucus creates an ideal environment for various microorganisms, particularly in the respiratory tract.

Pseudomonas aeruginosa is the organism most frequently associated with lung infections in patients with cystic fibrosis. This bacterium is notable for its capability to thrive in the thick mucus that characterizes the condition. It can form biofilms and is inherently resistant to many antibiotics, making it particularly challenging to treat. The chronic infection with Pseudomonas aeruginosa significantly contributes to lung damage and progressive respiratory decline in cystic fibrosis patients.

Other organisms that may be found in the lungs of cystic fibrosis patients include Staphylococcus aureus, but Pseudomonas aeruginosa is more prevalent and is considered a hallmark pathogen in this population. The other organisms listed, such as Escherichia coli and Klebsiella pneumoniae, are less commonly associated with lung infections in this context. Thus, Pseudomonas aeruginosa's predominance in cystic fibrosis makes it the correct choice for this question.