[Atypical pneumonia].

International epidemiologic surveys show that apart from community acquired "typical" pneumonia the number of cases caused by atypical pathogens are increasing. A number of problems are to be faced while diagnosing and treating the lower respiratory tract infections due to atypical pathogens. The article gives a detailed overview of pneumonia caused by Chlamydia pneumoniae, Chlamydia psittaci, Mycoplasma pneumoniae, Coxiella burnetti and Legionella species, and emphasizes that these pathogens should be considered and thought about more in lower respiratory tract infections as appropriate treatment, if started in time, decreases the risk of a more severe outcome.