In children with cystic fibrosis or HIV, which pulmonary infection is most commonly seen?

In children with cystic fibrosis or HIV, atypical mycobacterial disease is the infection most commonly associated with these conditions. This is particularly important to recognize because patients with cystic fibrosis often have compromised pulmonary function and an altered immune response, which predisposes them to infections that might not typically affect healthy children. Similarly, children with HIV have weakened immune systems due to the virus's impact on T-cell function, making them more susceptible to opportunistic infections, including atypical mycobacterial disease.

In the context of cystic fibrosis, the thick, sticky mucus in the airways serves as a medium for bacterial growth and may lead to chronic infections. While Staphylococcus aureus and Pseudomonas aeruginosa are more commonly associated with lung infections in cystic fibrosis, atypical mycobacterial disease, particularly caused by mycobacteria such as Mycobacterium avium complex, is more common in immunocompromised children, including those with HIV.

Pneumococcal pneumonia is a common cause of bacterial pneumonia in the general pediatric population, but it is not specifically associated with the immunocompromised state seen in cystic fibrosis or HIV. Rhinovirus infection, although prevalent, usually causes upper respiratory