Table 2.

Most common causative factor in community-acquired pneumonia by site of care

Outpatients (mild)	Non-ICU inpatients	ICU (severe)
S pneumoniae	S pneumoniae	S pneumoniae
M pneumoniae	M pneumoniae	Legionella spp
H influenzae	C pneumoniae	H influenzae
C pneumoniae	H influenzae	Gram-negative bacilli
Respiratory viruses*	Legionella spp	S aureus
	Aspiration respiratory viruses*

ICU=Intensive care unit.

^*Influenza A and B, adenovirus, RSV, parainfluenza. Based on collective data.18, 19, 24, 25, 26, 27, 28, 29, 30, 33, 35, 36