Table 2.
Most common causes of community-acquired pneumonia
| Patient Type | Cause |
|---|---|
| Outpatient | Streptococcus pneumoniae |
| Mycoplasma pneumoniae | |
| Haemophilus influenzae | |
| Chlamydophila pneumoniae | |
| Respiratory virusesa | |
| Inpatient (non-ICU) | S pneumoniae |
| M pneumoniae | |
| C pneumoniae | |
| H influenzae | |
| Legionella spp | |
| Aspiration | |
| Respiratory virusesa | |
| Inpatient (ICU) | S pneumoniae |
| Staphylococcus aureus | |
| Legionella spp | |
| Gram-negative bacilli | |
| H influenzae |
Based on collective data from recent studies.54
Abbreviation: ICU, intensive care unit.
a
Influenza A and B, adenovirus, respiratory syncytial virus, and parainfluenza.
From Mandell LA, Wunderink RG, Anzueto A, et al. Infectious Diseases Society of America/American Thoracic Society consensus guidelines on the management of community-acquired pneumonia in adults. Clin Infect Dis 2007;44:S27–72; with permission.