[A clinical study of bacterial infection in patients with chronic obstructive pulmonary disease].

OBJECTIVE

To investigate the association of bacteriologic characteristics and bacterial infection in small airway disease.

METHODS

Fiberoptic bronchoscopy and ultrathin fiberoptic bronchoscopy were performed on outpatients with COPD and chronic bronchitis both during stable stage and acute exacerbation. Samples were obtained from both large and small airways by protective specimen brush, and bacteria were cultured quantitatively.

RESULTS

The positive rates for pathogens in patients with COPD and chronic bronchitis during acute exacerbation were 26.6% (8/30) and 23.5% (5/17) respectively. Major pathogens in acute COPD include Staphylococcus aureus, Streptococcus pneumoniae, Hemophilus influenzae, Moraxella catarrhalis, and Pseudomonas aeruginosa. All of the pathogens were present in large airways, with 2 strains present in small airways concurrently. The positive rates for pathogens in stable COPD and chronic bronchitis were 24.0% (6/24) and 11.7% (2/17) respectively. Major pathogens found in stable COPD include Staphylococcus epidermis, Micrococcus and Streptococcus pneumoniae. The bacteria were less than 10 x 10(3) cfu/ml, present mainly in large airways. There was no significant difference in the extent of small airway diseases between COPD with bacterial infection and that without bacterial infection (P > 0.05).

CONCLUSIONS

Bacterial infection is not a major pathogenic factor in stable COPD. There is no direct cause-and-effect relationship between bacterial infection and the extent of small airway diseases in patients with COPD.