Viral infections in patients with cystic fibrosis (CF) have been linked to pulmonary exacerbations, according to the results of a study recently presented at the American Academy of Allergy, Asthma & Immunology Annual Meeting held March 4-7 in Los Angeles. The team of researchers from Columbia University Medical Center in New York also noted that these viral infections may be associated with alterations in the respiratory microbiome, but noted that additional studies are needed.
“Our research suggests that in pediatric patients with [cystic fibrosis], viral infections are associated with pulmonary exacerbations and changes in respiratory microbial communities may be part of the underlying mechanism,” Gina T. Coscia, M.D., of Columbia University Medical Center, said in a news release.
According to the team, the clinical status of patients with cystic fibrosis is negatively affected by the presence of viruses, but the impact of these viruses on the respiratory microbiome remains unclear.
The researchers, therefore, conducted a prospective longitudinal study to examine whether viruses negatively affected the microbiome in cystic fibrosis patients. A total of 102 patients with a diagnosis of cystic fibrosis who were younger than 22 were examined between 2013 and 2014. The researchers collected samples of the patients’ sputum, swab, bronchoalveolar lavage and oropharyngeal, at both baseline and during exacerbation states.
The team used Illumina sequencing and standard culture to identify the presence of bacteria. To identify the presence of viruses, the researchers used a method called quantitative real-time polymerase chain reaction.
A total of 380 samples were collected from the 102 patients. Of these, 73 tested positive for virus presence, and 307 tested negative. The most common viruses detected were rhinovirus/enterovirus and coronavirus. The researchers found that in those patients who tested positive for the presence of viruses, there was an association with a higher prevalence of traditional cystic fibrosis pathogens. However, there was no association between infection caused by viruses and patients’ lung function or clinical status.
Using deep sequencing, the researchers detected changes in the amount of microbiota bacteria in virus-positive samples compared with samples that were negative for the presence of virus.
“Detection of viruses in pediatric patients with cystic fibrosis may predict subsequent infection with traditional CF pathogens,” Coscia and colleagues wrote. “Viruses may also be associated with subtle changes in the microbiome but further analysis is needed.”
Cystic fibrosis is a genetic condition in which the lungs and digestive system become clogged with thick, sticky mucus. Symptoms usually start in early childhood and include persistent cough, recurring chest and lung infections, and poor weight gain. Cystic fibrosis affects at least 30,000 people in the United States, and between 900 and 1,000 new cases are diagnosed every year. One in 29 people of Caucasian ancestry is an unaffected carrier of the CF gene mutation. In the U.S., the condition occurs at a rate of 1 in 3,400 births.