Detection of viral and bacterial respiratory pathogens in patients with cystic fibrosis.

The presence of viral respiratory infections is associated closely with exacerbations in patients with cystic fibrosis. Viral and bacterial multiplex PCRs were developed and applied to nasal swab samples from children with cystic fibrosis. This showed a large number of individuals with cystic fibrosis were infected with rhinoviruses, and more were infected with viral than bacterial pathogens. All individuals with parainfluenza 3 virus had clinical exacerbations of their cystic fibrosis, and although 3/4 of these children were co-infected with HRV. The findings do not suggest a significant association for any other virus or bacteria with exacerbation. There is clear evidence some viral infections are associated with cystic fibrosis that dual infection is more likely to produce symptoms, and mechanisms of viral-induced exacerbation should be elucidated.