Bacterial infection in chronic obstructive pulmonary disease. A study of stable and exacerbated outpatients using the protected specimen brush.

The lower airways of asymptomatic chronic obstructive pulmonary disease (COPD) patients can be colonized by bacteria, mainly Haemophilus influenza, Streptococcus pneumoniae, and Moraxella catarrhalis. However, the role of lower airway bacteria in stable and exacerbated COPD has not been well defined. To determine the importance of lower airway bacterial infection in COPD we studied 40 outpatients with stable COPD (Group A: age 61.1 +/- 9.9 yr; [mean +/- SD]; FEV1/FVC 51.7 +/- 12.5) and 29 outpatients with exacerbated COPD (Group B: age 63.4, SD 9.0 yr; FEV1/FVC 52.0, SD 9.6), using the protected specimen brush (PSB) for microbiology sampling. Group A consisted of outpatients with stable COPD having normal or near-normal chest X-rays, with clinical indications for performing fiber-bronchoscopy (pulmonary nodule, remote hemoptysis); Group B consisted of patients with exacerbated COPD who voluntarily accepted lower airway microbiology sampling. To avoid contamination by upper airway flora the PSB was used for bacterial sampling in all the cases and concentrations > or = 1,000 colony-forming units/milliliter (CFU/ml) were considered positive. Results were as follows: Group A: Lung function data in outpatients with stable COPD were lower than the reference values for this population (FVC 2.97 +/- 1.02 L, FVC% 71.4 +/- 22.4, FEV1 1.59 +/- 0.79 L, FEV1% 51.2 +/- 23.0). Positive PSB cultures were obtained in 10 of 40 cases (25%), mainly of H. influenzae and S. pneumoniae. Two of 40 cases had positive cultures at concentrations > or = 10,000 CFU/ml (5.0%).(ABSTRACT TRUNCATED AT 250 WORDS)