Pus in Sputum Associated with Disease-prone Bacteria in Bronchiectasis

Pus in Sputum Associated with Disease-prone Bacteria in Bronchiectasis

The presence of pus (purulence) in sputum samples from bronchiectasis patients is associated with an imbalance in microbial communities and a higher prevalence of potential disease-prone bacteria, a new study suggests.

The study, “Sputum purulence-associated microbial community compositions in adults with bronchiectasis” was published in the Journal of Thoracic Disease.

Sputum, which results from overproduction of mucus and intense airway inflammation, is one of the major complaints among bronchiectasis patients. Clinically, sputum purulence has been important in reflecting the intensity of inflammation and infection of the airways in these patients, and purulence is also usually associated with the presence of a pathogen.

Antibiotics are usually prescribed based on sputum purulence characteristics, the volume of mucus and the frequency of coughing.

However, antibiotics are often prescribed without a bacteria culture confirmation, which shows what bacteria are more prominent in the sputum. Nonetheless, bacteria cultures can be misleading; many disease-causing (pathogenic) bacteria are not easily cultured.

Researchers aimed to characterize how purulence correlates with the types of bacteria present in the sputum of bronchiectasis patients. To do so, they analyzed 105 sputum samples from bronchiectasis patients to compare bacterial diversity between purulent and non-purulent sputum, as well as culture-positive and culture-negative purulent sputum.

Researchers also analyzed samples collected during exacerbation episodes (48 or more hours of worsening symptoms), and compared them to samples collected from the same patients during the stable phase of the disease.

The results further confirmed a study from 2012 showing that sputum purulence was strongly associated with infections with potentially pathogenic bacteria.

The data now obtained showed that purulent sputum samples from which it was possible to culture bacteria displayed the highest degree of airway dysbiosis — alteration of the type of bacteria usually present in healthy airways. In these patients, the most prominent bacteria were Proteobacteria and/or Pseudomonas spp., which are potentially pathogenic.

These patients (with purulent culture-positive sputum) were also the group who had the least variation in bacterial diversity between the stable phase and exacerbation episodes, maintaining the same variety of bacteria. This indicates that sputum purulence and bacteria culture findings might be complementary in guiding treatment decisions.

Overall, the results suggest that bacterial “culture findings coupled with sputum purulence assessment may better guide clinicians for antibiotics prescription,” the team concluded.