[Microbiological diagnosis of lower respiratory tract infections].

Successful microbiological diagnosis of lower respiratory tract infections demands a close cooperation between clinician and clinical microbiologist. Because of the broad spectrum of possible respiratory pathogens precise requests are necessary for adequate laboratory procedures. The high rate of potential pathogens requires quantitative microbiological and cytological data in order to differentiate between colonisation and infection. Pathophysiological reactions on microbial colonisation of the bronchial tree may contribute to acute exacerbations of a chronic bronchitis. The precise role of microbial nocuous agents, however, remains to be clarified.