Epidemiology of micro-organisms responsible for community-acquired pneumonia]

Pneumonias occupy a prominent situation among lower respiratory tract infections where they are remarkable for their potential mortality and for our relative knowledge of the responsible micro-organisms. Analysis and synthesis of each series published must answer several questions, such as: what are the lung diseases considered? which investigations have been performed? which criteria of imputability have been used? in which patients has the study been carried out? in which place, which period and which structure? In spite of methodological lacunae and of the inhomogeneous answers to the questions asked, there is some concordance between the series found in the literature. Thus, more than 90% of community-acquired pneumonias with microbiological identification are caused by Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma pneumoniae, Legionella pneumophila, Chlamydia psittaci (or pneumoniae), or Influenza A virus.