Table 3.
Epidemiology and etiology of community-acquired pneumonia based on medical history
| Medical history | Possible etiology |
|---|---|
| Host | |
| Alcoholism | S pneumoniae, anaerobes, aerobic gram-negative rods |
| COPD/smoker | S pneumoniae, H influenzae, M catarrhalis, L pneumophilia |
| Poor dental hygiene | Anaerobes |
| HIV infection (early stage) | S pneumoniae, H influenzae, M tuberculosis |
| HIV infection (CD4 cell counts < 200/μL) | P jiroveci, S pneumoniae, H influenzae, C neoformans, M tuberculosis |
| Granulocytopenia | Aerobic gram-negative rods |
| Environmental | |
| Increased terrorist activity | B anthracis, Y pestis, F tularensis |
| Exposure to contaminated air-conditioning cooling towers; hot tubs; recent travel and stay in a hotel; grocery store mist machine; visit to or recent stay in a hospital with drinking water contaminated by Legionella pneumophilia | L pneumophilia |
| Exposure to infected parturient cats, cattle, sheep, or goats | C burnetti |
| Pneumonia develops after windstorm in an area of endemicity | C immitis |
| Outbreak of pneumonia in shelter for homeless men or jail | S pneumoniae, M tuberculosis |
| Outbreak of pneumonia in military training camp | S pneumoniae, C pneumoniae, adenovirus, M pneumoniae |
| Outbreak of pneumonia in a nursing home | C pneumoniae, S pneumoniae, RSV, influenza A virus |
| Exposure to contaminated bat caves; excavation in areas of endemicity | H capsulatum |
| Exposure to turkeys, chickens, ducks, or psittacine birds | C psittaci, avian influenzaa |
| Exposure to mice or mice droppings | Hantavirus |
| Exposure to rabits | F tularencis |
| Travel history | |
| Travel to Thailand or other countries in Southeast Asia | B pseudomaleii (melioidosis) |
| Immigration from countries with high endemic prevalence of tuberculosis | M tuberculosis |
| Travel to endemic areas of SARSa | SARS-corona virus |
| Occupational history | |
| Health care worker | M tuberculosis, acute HIV seroconversion with pneumonia |
| Tick bite | Rocky Mountain spotted fever, Ehrlichia species |
Adapted from Mandell LA, Marrie TJ, Grossman RF, et al. Canadian guidelines for the initial management of community-acquired pneumonia: an evidence-based update by the Canadian Infectious Diseases Society and the Canadian Thoracic Society. Clin Infect Dis 2000;31:383–421; with permission.
a
Endemic areas of these agents may change from year to year. Physicians should consult www.cdc.gov, www.who.int periodically.