A large Irish study found that patients with cystic fibrosis (CF) who have lung infections with both Aspergillus fumigatus (AF) and Pseudomonas aeruginosa (PA) have a poor prognosis, compared to those with persistent PA infections.
Co-colonization with these two microorganisms may contribute to the damage of the airways of these patients with a major impact on their clinical outcome.
The findings were featured in the study “Co-colonisation with Aspergillus fumigatus and Pseudomonas aeruginosa is associated with poorer health in cystic fibrosis patients: an Irish registry analysis,” published in the journal BMC Pulmonary Medicine.
CF patients are at risk of contracting lung infections because of their thick airway mucus and inability to effectively clear it. Lung infections are not only responsible for CF patients’ decreased lung function but also for to up 95 percent of the deaths associated with the disease. Given so, it is important to understand and identify the clinical implications of microorganism infections on this very susceptible population.
Researchers evaluated the incidence of persistent and intermittent colonization with PA bacterium or AF fungi, and possible associations with clinical status of CF patients.
Both these microorganisms were previously reported as the most common bacterium and fungi found in 40 to 60 percent of CF patients. After evaluating data collected from the Cystic Fibrosis Registry of Ireland (CFRI) database, researchers found that the incidence of these microorganisms in the Irish population was lower than previously reported.
From a total of 749 patients with CF evaluated, 11 percent presented AF infection; PA infection was found in 31 percent; and only about 3 percent of the patients presented co-infection with both microorganisms.
Co-colonization with AF and PA was found to be associated with reduced lung function, with 13.8 percent reduction in forced expiratory volume. In addition, these patients also presented higher levels of exacerbations, hospitalizations, and antimicrobial drugs usage compared to non-colonized patients.
Overall, these clinical features were comparable to those observed in patients with persistent PA infection.
Finally, the authors reported that patients with persistent PA infection showed a higher prevalence of CF-related diabetes (CFRD) than patients with no infections. This association had been reported previously and it is well accepted in the field that insulin deficiency in these patients is associated with clinical decline.
“We hypothesize that these PA-AF interactions may play a role in the damaging pathology associated with CF airway disease and may explain why patients who are co-colonized with PA and AF have a poorer prognosis than those who are clear of both pathogens,” the authors wrote.
Additional studies on the interaction of these microorganisms are needed to fully understand its relevance for CF progression and severity.