[Community-acquired pneumonia--current status of pathogen diagnosis].

Procedures for the microbiological diagnosis of acute community-acquired pneumonia are based on the expected pathogens. Although a great variety of microorganisms are able to cause community-acquired pneumonia only a few pathogens play an important role in daily practice. The most important investigations are blood cultures and sputum cultures to detect bacteria like pneumococci, Haemophilus influenzae and Staphylococcus aureus as well as antibody tests for Mycoplasma pneumonia and Chlamydia pneumonia. According to anamnesis and clinic presentation tests such as for Legionella or viruses have to be added. Sometimes also rare pathogens have to be considered such as Coxiella burnetii, Leptospira, Hantaviruses, cryptococci or Chlamydia psittaci. The standard procedure for diagnosis of tuberculosis is the microscopical examination and the standardized culture in liquid and on solid media. Amplification methods such as PCR are also useful for a rapid diagnosis. However, the application of amplification procedures alone without culture is not recommended.