Bacterial isolates and cigarette smoking in patients with chronic bronchitis: results from an Italian multicenter survey.

Patients who were cigarette smokers suffering exacerbations of chronic bronchitis were examined in eight outpatient clinics in five regions of Italy, three from the South (Campania, 82 patients; Sicily, 82 patients; and Puglia, 29 patients) and two from North (Lombardy, 33 patients; and Liguria, 50 patients). Haemophilus influenzae was the most frequently isolated bacterium in the patients' sputum (in 30% of the total group), followed by Streptococcus pneumoniae (in 20%), Staphylococcus aureus (in 25%), and Branhamella catarrhalis (in 7%). H. influenzae was the most common bacterium in the South (in 37%) and S aureus in the North (in 13%). Smoking index scores (number of cigarettes smoked daily x years of smoking) were 827 in patients in whom H influenzae was isolated; 691 in patients with S aureus; 599 in patients with S pneumoniae; 542 in patients with B catarrhalis; and 446 in patients in whom no isolates were found. Pulmonary function was most severely decreased in patients positive for H influenzae and S aureus. The results indicate an association between heavy cigarette smoking and lower respiratory tract infections that is influenced by regional differences.