Bacterial flora of the lower respiratory tract in children with bronchial asthma

The aims of this retrospective study were to (i) determine the risk of cont amination of lower respiratory tract samples obtained during fiberoscopy in children; (ii) determine the incidence and profile of the bacterial flora of the lower respiratory tract in a selected group of asthmatic children at high risk For bacterial infection; and (iii) identify risk markers for suc h findings. In 29 asthmatic children, comparison of bacterial cultures of s pecimens obtained from the upper and lower respiratory tracts showed that c ontamination was a possibility in only 3.4% (1/29) of cases. The results fr om bacterial samples obtained via flexible bronchoscopy in a further 273 co nsecutively investigated physician-diagnosed asthmatic children were analys ed. Patients were selected for bronchoscopy if they had severe chronic asth ma or in order to exclude other diseases able to provoke wheezing. Their me an (SD) and median ages were 32.2 (38.3) and 17.5 mo, respectively. The inc idence of positive bacterial cultures was 12.1% (33/273 patients). Bacteria l flora included H. influenzae (39.5%, 15/38), B. catarrhalis (23.7%, 9/38) , Neisseria species (7.9%, 3/38), M. pneumoniae (7.9%, 3/38, P. non-aerugin osa (5.3%, 2/38) and P. aeruginosa (2.6%, 1/38). No clinical or radiologica l markers were significantly associated with lower respiratory tract bacter ial infection. Large quantities of bacteria were present in the lower respi ratory tracts of a substantial number of children (1/8) in this selected gr oup of asthmatics. For the moment, however, the clinical implications of th is finding remain unclear.