[Study on the relationship between airway bacterial infections and acute exacerbations in patients with chronic obstructive pulmonary disease].

Objective: The purpose of this study was to observe the bacterial infections of respiratory tract in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD).
Methods: 130 patients with AECOPD in outpatient department, emergency room or in wards were studied prospectively. Patients were divided into different groups according to both Anthonisen's classification and their lung function status. Sputum were cultured together with bacteria positive rate and types of AECOPD as well as the damage degree of lung function were analyzed.
Results: Of 130 sputum samples, 50 showed positive through culture (38.5%) and 60 strains of pathogens were isolated. Predominant pathogens isolated would include Haemophilus parainfluenzae (20/60), Streptococcus pneumoniae (5/60) and Haemophilus influenzae (10/60). Positive rate of bacterial culture in type 1 AECOPD was 55.0%, higher than those of type 2 (38.3%) and type 3 (18.5%)(P = 0.01) and was increasing with the decrease of lung function of patients with AECOPD (P < 0.02).
Conclusion: Positive rate of bacterial culture in patients of type 1 AECOPD was the highest one. Haemophilus parainfluenzae was one of the most important pathogens in AECOPD. There seemed a correlation between positive result of bacterial culture and the severity of COPD.