At present, the epidemiological characteristics and the distribution of pathogens of community-acquired pneumonia in Shandong Province are not clear. In order to understand the characteristics of community-acquired pneumonia, the distribution of pathogens and the risk factors of complications in Shandong Province, it is necessary to carry out investigation and study, which will provide the basis and support for the future prospective cohort study of pulmonary infection.

Inclusion Criteria:

• Age > 14 years.
• In the community.
• Chest X-ray showed patchy, patchy infiltrative shadows or interstitial changes with or without pleural effusion (in or out of hospital) .
• Pneumonia-related clinical manifestations: 1) recent cough, expectoration or respiratory disease symptoms aggravated, and the emergence of purulent sputum, with or without chest pain. 2) fever: armpit temperature ≥37.3℃ or hypothermia: armpit temperature <36℃. 3) signs of pulmonary consolidation and/or Wet Rales. 4) white blood cell > 10 × 10^9/L or < 4 × 10^9/L with or without left shift of nucleus. Comply with 1,2,3 above plus any one of 4 above.

Exclusion Criteria:

• The patients were initially diagnosed with pulmonary neoplasms, tuberculosis, non-infectious interstitial disease, pulmonary edema, atelectasis, pulmonary embolism, pulmonary eosinophil granulocyte infiltration and pulmonary vasculitis.
• Human Immunodeficiency Virus.
• The patient was readmitted within 72 hours of discharge and was classified as a single hospitalization.

All patients aged over 14 years with community-acquired pneumonia were confirmed by imaging.