Studies of role of normal upper airway flora in lower respiratory tract infection by transtracheal aspiration

Abstract

We studied by trastracheal aspiration (TTA) the relationship between lower respiratory tract infections and normal upper airway flora. This was done by comparing the organisms obtained by TTA with these in the sputum in 58 patients with lower respiratory tract infection. In some patients, the organisms obtained by TTA were not identical with those in the sputum. In 23% of cases with chronic lower airway infection, organisms by TTA were not identical in the organisms in the sputum. We identified altogether 19 species of organisms in TTA and 23 species in sputum. By TTA, We identified 2 or more organisms in 54% casesOrganisms identified as follows; H. influenzae (48%), S. pneumoniae (38%), B. catarrhalis (15%) and H. parainfluenzae (15%) by TTA and a-streptococcus (65%), nonpathogenic Nisseria (70%), H. influenzae (24%) and S. pneumoniae (28%) in sputum.In 90% of the cases with chronic lower airway infections, we identified the above organisms by TTA and in some cases we repeatedly cultured the same organisms, from the same patients.From the results we realize that the organisms of upper airway flora go through readily into lower airway. Particularly, by chronic infections of lower airway, invaders seem to be settled at the location of lower part, and produce bacterial colonies. Thus, in the chronic infectious diseases of the lower airway, the organisms that live always in upper airway could play an important role on it.