Which pathogen is the most common cause of pneumonia in children with cystic fibrosis under the age of 20?

In children with cystic fibrosis, Pseudomonas aeruginosa is recognized as the most common pathogen implicated in pneumonia, particularly as these patients age. This bacterium thrives in the thick mucus characteristic of cystic fibrosis, establishing chronic infections that can lead to progressive lung disease.

While Staphylococcus aureus can also cause pulmonary infections in cystic fibrosis patients, especially in younger children or during the initial stages of the disease, it is not the predominant pathogen in this population after childhood. The significant prevalence and pathogenicity of Pseudomonas aeruginosa make it the main concern for patients with cystic fibrosis under 20 years of age. Understanding the evolution of bacterial infections in this demographic is crucial, as managing chronic infections and preventing exacerbations is a key aspect of care in cystic fibrosis.

Other pathogens listed, such as Streptococcus pneumoniae and Escherichia coli, have different epidemiological profiles and are not primarily associated with the chronic lung infections typical in cystic fibrosis patients.