[Microbiological diagnosis of deep respiratory tract infections from the clinical viewpoint].

The appropriate use of the clinical microbiology laboratory for diagnosing lower respiratory tract infections is controversial. While examination of sputum does not help to determine the etiology in most patients with acute bronchitis, a recent study confirmed the sense of culturing sputum in patients with exacerbation of COPD. In patients with pneumonia, microbiological investigations include evaluation of sputum samples, antigentests and PCR tests as well as invasive methods of sampling with qualitative and quantitative cultures. However, there is no uniform recommendation for these investigations.