Agent | Mostly Legionella pneumophila sg1 | Legionella longbeachae in potting soils (community acquired) |
Reservoir | Cooling towers | Potting and compost (community acquired) |
| Hot and cold water systems | Respiratory therapy equipment (healthcare associated) |
| Recreational pools and spas | |
Mechanism of transmission | Inhalation of contaminated aerosols | Aspiration or direct instillation into the lung during respiratory tract manipulations (healthcare associated) |
| Aspiration possible | Wound infection (healthcare-associated) |
Risk factors (environmental) | Warm season | Accommodation with seasonal/irregular water use (travel associated) |
| Poorly designed and poorly maintained water systems | |
| Poor water temperature control | |
Risk factors (hosts) | Increasing age | Recent surgery (healthcare associated) |
| Male | Intubation (healthcare associated) |
| Smoking | Aspiration (healthcare associated) |
| Chronic lung disease | |
| Diabetes | |
| Conditions associated with immunodeficiency | |