INFECTIVE EXACERBATIONS OF CHRONIC-BRONCHITIS - RELATION BETWEEN BACTERIOLOGICAL ETIOLOGY AND LUNG-FUNCTION

Study objective: In patients with severe COPD, acute infective exacerb ations are frequent. Streptococcus pneumoniae and Haemophilus influenz ae are the most commonly isolated bacteria in sputum cultures from the se patients, We hypothesized that in patients with advanced disease, G ram-negative bacteria other than H influenzae play at least an equally , important role. Methods: We evaluated clinical data and sputum cultu re results from 211 unselected COPD patients admitted to our hospital with an acute infective exacerbation of COPD. One hundred twelve patie nts fulfilled our protocol criteria of reliable microbiologic results and reproducible lung function tests; the patients were categorized ac cording to the recently published three stages of severity. Results: L ung function tests revealed an FEV1 of greater than or equal to 50% of the predicted value in 30 patients (stage I), an FEV1 of 35% to <50% of the predicted value in 30 patients (stage II), and an FEV1 of less than or equal to 35% of the predicted value in 34 patients (stage III) , Bacteria were classified into three groups: group 1 contained S pneu moniae and other Gram-positive cocci; group 2, H influenzae and Moraxe lla catarrhalis; and group 3, Enterobacteriaceae and Pseudomonas spp, For all patients together, the most frequently isolated bacteria were group 3 organisms (Enterobacteriaceae and Pseudomonas spp, 48.2%), fol lowed by group 1 organisms (S pneumoniae and other Gram-positive cocci , 30.4%), and group 2 organisms (H influenzae and M catarrhalis, 21.4% ). In stage I patients, 14 of 30 had bacteria from group 1, seven of 3 0 had group 2, and nine of 30 had group 3, In stage II patients, eight of 30 had group 1 bacteria, 10 of 30 had group 2, and 12 of 30 had gr oup 3. In stage III patients, 12 of 52 had group 1 bacteria, seven of 52 had group 2, and 22 of 52 had group 3. The three groups of bacteria causing infective exacerbations were unevenly distributed among the t hree severity stages of lung function (p=0.016).Conclusion: There is a correlation between deterioration of lung function and the bacteria i solated from patients with infective exacerbations of COPD, In acute i nfective exacerbations, Enterobacteriaceae and Pseudomonas spp are the predominant bacteria in patients with an FEV1 less than or equal to 3 5% of the predicted value.