Cystic fibrosis patients have more good and bad bacteria in their lungs, study finds

A large multicenter study found that patients with cystic fibrosis (CF) – who tend to develop chronic lung infections – had more good and bad bacteria in their lungs compared to controls. The study used bronchoalveolar lavage, in which a bronchoscope is directed into the lung to directly collect lung secretions, and also found less diversity of bacteria in the lungs of CF patients who were older and had more lung disease or inflammation. Results, published in the European Respiratory Journal, provide a basis for future treatment studies.

"Just like the human gut, the lungs are home to many different communities of bacteria that normally do not cause disease and are associated with good health," said study co-author Susanna McColley, MD, from Stanley Manne Children's Research Institute at Ann & Robert H. Lurie Children's Hospital of Chicago, and Professor of Pediatrics at Northwestern University Feinberg School of Medicine. "Young children with cystic fibrosis have many of these 'good' or normal bacteria in the lung. However, in cystic fibrosis patients, these common bacteria occur in an environment where there is more inflammation compared to children with other diseases. A potential interpretation of our data is that 'normal' bacteria in the lungs of cystic fibrosis patients might contribute to inflammation and chronic disease. This is a question that could be tackled by future studies."

McColley also points out that the study's data could serve as baseline for future intervention studies on preserving bacterial diversity in the lung as a potential strategy to reduce chronic infections with damaging bacteria in CF.

"We use a lot of antibiotics to treat CF lung disease, which can reduce the number and diversity of normal bacteria in the lung. We do not know whether this decreased bacterial diversity contributes to lung disease in cystic fibrosis or is just a side effect of treatment," said McColley. "To address this question we could study the effects of giving antibiotics over time, or examine if there are ways to manipulate the bacterial diversity in the lungs with probiotics. Our study results could have important impact on generating hypotheses and designing intervention studies to improve outcomes for patients with cystic fibrosis."