Background: The presence of bacteria causing infection in the airways is associated with neutrophil recruitment thus correlating with the degree of yellow-green coloration of the sputum due to neutrophil myeloperoxidase accumulation. Therefore purulence of the sputum can be used as a guide. The BronkoTest, a standardized sputum color chart was developed as a tool to assess sputum color. In this study, the diagnostic accuracy of BronkoTest in detecting bacterial infection in patients with chronic lung diseases such as chronic obstructive pulmonary diseases (COPD) and bronchiectasis was determined.
Methods: A prospective, cross sectional study involving 89 patients who were diagnosed with chronic lung diseases such as COPD and bronchiectasis presenting with sputum production. A fresh sputum sample was obtained and simultaneously assessed by the doctor, patient, and nurse. Sputum samples were then compared with the colors of BronkoTest colour chart. Samples graded as 1 and 2 as mucoid sputum while grades 3-5 were interpreted as purulent. Gram staining and culture were subsequently done.
Results: A total of 89 patients participated in the study. Eighty-five percent of the population has COPD and 15% has bronchiectasis. Eighty-four percent of patients were treated with inhaled corticosteriods and this was significantly associated with sputum purulence (p value =0.013). A higher rate (61%) of bacterial growth was found in purulent samples. The most common bacterium isolated was Klebsiella pneumonia. The sensitivity and specificity were 88.89% and 63.69%, respectively.
Conclusion: Assessing sputum color using BronkoTest in patients with chronic respiratory diseases like COPD and bronchiectasis predicts bacterial presence and provide both patients and physicians a simple and noninvasive method to facilitate the need for response to antibiotic therapy.