Final answer:
Bronchiectasis is commonly associated with cystic fibrosis, involving an infection by Pseudomonas aeruginosa, which thrives in the altered mucus of CF patients and is known for its antibiotic resistance.
Step-by-step explanation:
The correct statement regarding bronchiectasis is that it is common in cystic fibrosis (CF). In the context of CF, Pseudomonas aeruginosa is a frequent bacterial pathogen that infects the airways, as the altered mucus in CF patients provides an ideal environment for this organism to thrive and form biofilms. This is particularly important since Pseudomonas aeruginosa is known for its antibiotic resistance and can lead to serious lung damage due to the chronic inflammatory response. It's important to note that while the bacterium Streptococcus pneumoniae is a common cause of community-acquired pneumonia, it is not the most common bacterial pathogen associated with bronchiectasis in CF.