The importance of investigating the role of the airway microbiome in lung damage associated with cystic fibrosis (CF) was the focus of two talks at the recent 30th Annual North American Cystic Fibrosis Conference (NACFC) in Orlando, Florida.
Both talks were based on the topic, “Microbiome Studies Can be Helpful in Understanding CF Infections.”
CF and CF manifestations, particularly pulmonary exacerbations, need to be treated with appropriate antibiotics. The correct selection of these drugs has largely been guided by microbiologic insights provided by the selective culture of bacteria from respiratory samples.
While patients have benefited considerably from this approach in the past decades, a new method, called “culture-independent” approaches, provides greater insight into the composition and dynamics of airway bacterial communities (collectively referred to as airway microbiota). In fact, these methods have shown that the earlier, standard cultures approach underrepresent the number of bacterial species in CF respiratory samples.
Using the cultures approach, a relatively low number of bacterial species in CF were identified, namely Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus aureus, Burkholderia cepacia complex, and a few others. While these organisms were considered “typical” CF pathogens, the “culture-independent” approaches suggest that CF airways may be infected by many more bacterial species than thought.
These new approaches have also shown an intrinsic pattern in bacterial communities: they appear to increase in the first decade of life, and then decrease throughout adolescence and adulthood in parallel with lung function decline.
Several lines of evidence now indicate that oral bacteria have only a marginal impact on measures of airway microbiota. Studies comparing the microbiome from oral and lower airway samples found significant differences: “atypical CF pathogens,” including anaerobes, have been detected directly in the lower airways. This suggests that species present in the lower airways may, in fact, contribute significantly to the devastating clinical manifestations of CF.
The talks highlighted that investigating the CF airway microbiome is mandatory to further understand the mechanisms underlying or associated with the disease. Most important is identifying the alterations in microbial community composition and activity that associate, and even predict, changes in clinical state and lung disease progression.