The aim of the study is to investigate the bacterial causes in community acquired pneumonia in adults admitted to hospital in two counties in Norway and to look at possible factors that makes the patients susceptible to pneumonia.

In Norway there is little knowledge of which bacterias that causes pneumonia in patients admitted to hospital. There are also few registered cases of Legionnaires disease every year, compared to our neighbour countries.

Therefore 500 patients with community acquired pneumonia admitted to Telemark hospital and Ostfold hospital in Norway will be tested by urin antigen test for the detection of Legionella pneumophila serogroup 1 and Streptococcus pneumoniae. We will also perform routine bacterial culture of sputum and culture on medium for isolation of Legionella species. A throat swab from the patients will be tested for Mycoplasma pneumoniae, Chlamydophila pneumoniae and Bordetella pertussis using PCR-techniques. Legionella-serology will also be performed. In addition all the included patients are invited to fill in a questionnaire in order to look for risk factors for developing community acquired pneumonia.

Inclusion Criteria:

• Symptoms of lower airway infection and radiologic sings of pneumonia.

Exclusion Criteria:

• Age<18
• Serious psychiatric illness
• Mentally retarded
• Hospitalized last 14 days

Patients admitted to hospital with community acquired pneumonia.