[The role of atypical microorganisms and viruses in severe acute community-acquired pneumonia].

Usually, intensivists do not focus on atypical bacteria and viruses in severe community-acquired pneumonia (CAP). Only and virus, following the recent H1N1 influenza pandemic, are routinely suggested as responsible agents. However, CAP due to atypical bacteria may represent up to 44% of all CAP. Viral CAP is considered less severe than the usual bacterial ones, although 25% of them warrant hospitalization and 15% result in severe sepsis. Even though is the most frequently atypical pathogen involved in severe cases, may be responsible for multiorgan failure. To date, tools including detection of in urine and using polymerase chain reaction (PCR) allow rapid and accurate diagnosis. The treatment is based on macrolides and fluoroquinolones that can be associated in severe Legionnaire diseases. The presence of virus in CAP, either alone or in association with bacteria, has been demonstrated using molecular biology tests. These techniques also allowed the identification of several new viruses in CAP. However, the exact role of these detected viruses in CAP as well as the efficiency of antiviral therapy still represent major unsolved concerns.