Researchers at the University of Michigan Medical School recently published in the journal Microbiome findings indicating that lung microbiota alterations observed during disease onset in individuals with cystic fibrosis may become useful as predictors of exacerbations. The study is entitled “The daily dynamics of cystic fibrosis airway microbiota during clinical stability and at exacerbation.”

CF is a life-threatening genetic disease in which a defective gene causes the body to form unusually thick, sticky mucus that is difficult to cough up and can result in serious respiratory and gastrointestinal manifestations. Recent studies have shown that the airways of CF patients usually harbor complex bacterial communities, also referred to as microbiota. The day-to-day variability of these airway communities is unknown and its dynamics during the disease onset of symptoms in terms of respiratory exacerbations are poorly elucidated.

In the study, researchers obtained 95 daily sputum samples from four CF patients and characterized alterations in the bacterial and viral airway community in two different periods: during clinical stability and during the onset of pulmonary exacerbations, prior to antibiotic treatment for the exacerbation.

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Researchers found variable day-to-day stability in the patients’ airway microbiota in periods of clinical stability, although overall the microbiota remained relatively stable. Distinct patterns of microbiota alterations were observed at the onset of exacerbation between the different CF patients. One of the patients had a decrease in Staphylococcus abundance and an increase in the relative abundances of Pseudomonas and Prevotella bacteria, while other patient had an intermittently shift from a lung microbiota dominated by Burkholderia to one dominated by Pseudomonas. Common features were also observed, for example, researchers found that in three patients, the dominant taxon (Staphylococcus, Burkholderia, and Streptococcus in this case) decreased in relative abundance at the time of exacerbation, suggesting a possible role for less abundant bacterial taxa in some exacerbations. No viruses were detected in the patients analyzed.

The research team concluded that during periods of clinical stability, the airway microbiota of CF patients is relatively stable and that the onset of symptoms of some pulmonary exacerbation may be predicted by marked alterations in the microbiota. The team believes that microbiota change patterns might become useful to predict and manage CF pulmonary exacerbations. Further studies with larger sample sets should be conducted to better characterize the spectrum of microbiome alterations linked to pulmonary exacerbations in CF patients.