Lower airways distinct in cystic fibrosis, even in younger children
There are distinct differences in airway microbiota and inflammation in lower airway samples of patients with cystic fibrosis across a range of ages, researchers reported in PLOS ONE.
“We compared lower airway samples from bronchoscopy in children with cystic fibrosis and disease controls across the age spectrum and used genetic sequencing to identify microorganisms, finding that a few common cystic fibrosis pathogens begin to dominate at very early ages,” John B. O’Connor, MA, clinical research associate in the division of pulmonary and sleep medicine in the department of pediatrics at Ann & Robert H. Lurie Children’s Hospital, Chicago, said in a related press release. “Such a clear split from disease controls in this young age group has not been shown before.”
Researchers evaluated clinical data and bronchoalveolar lavage fluid samples from 191 participants up to age 21 years. Researchers measured total bacterial load and performed gene sequencing to characterize bacterial communities in the samples with species-level sensitivity for select genera.
Sixty-three patients had cystic fibrosis (mean age, 9.7 years; 65% female). The researchers reported higher bacterial load and lower microbial diversity in samples from patients with cystic fibrosis. In addition, these samples also had a divergence from disease controls aged 2 to 5 years and higher neutrophilic inflammation relative to bacterial burden, according to the results.
Researchers observed an increase in traditional cystic fibrosis pathogens and decreased Streptococcus mitis, S. oralis and S. pneumoniae species in the samples from older participants with cystic fibrosis. The most prevalent species-level taxa were S. mitis/oralis/pneumoniae (52%) and Prevotella melaninogenica (44%).
There was increased diversity in the heterogenous disease controls independent of cystic fibrosis diagnosis and indication, the researchers wrote.
Antibiotic exposure was more common in control participants compared with patients with cystic fibrosis (90% vs. 45%; P < .001). Antibiotic exposure was associated with lower neutrophilic inflammation (P = .002) and lower bacterial burden (P = .049).
There were no significant differences in bacterial diversity and lung function between participants who received antibiotic treatment and those who did not.
“A more in-depth evaluation of the airway microbiome and how it incites inflammation early in life may provide valuable insight into the development of cystic fibrosis lung disease with the potential for interventions to mitigate disease progression,” the researchers wrote.