Bacteriological findings in the transtracheal aspirate from patients with acute exacerbation of chronic bronchitis.

Transtracheal aspirates from 87 patients with acute exacerbations of chronic bronchitis who had received no recent antibiotic treatment were examined. A single bacterial species was found in 83% of positive cultures. Predominant pathogens were Haemophilus influenzae and Streptococcus pneumoniae which occurred jointly or separately in 50% of positive cultures. Bacteria traditionally considered as non-pathogenic for the lower respiratory tract also appeared to play an aetiological role. Enterobacteriaceae and anaerobes were infrequent. No bacterial growth was found in 11 cases.