Table 2.

Epidemiologic conditions related to specific pathogens with selected community-acquired pneumonia

Condition	Commonly encountered pathogens
Alcoholism	S pneumoniae, oral anaerobes
Chronic obstructive pulmonary disease and/or smoking	S pneumoniae, H influenzae, M catarrhalis, Legionella spp, Chlamydia pneumoniae
Poor dental hygiene	Oral anaerobes
Aspiration/Lung abscess	Oral anaerobes
Exposure to bats or soil enriched with bird droppings	Histoplasma capsulatum
Exposure to birds	Chlamydia psittaci, avian influenza (poultry exposure)
Exposure to rabbits	Francisella tularensis
Exposure to farm animals or parturient cats	Coxiella burnetti (Q fever)
HIV infection (early)	S pneumoniae, H influenzae, M tuberculosis
HIV infection (late)	Above plus J carinii, Cryptococcus, Histoplasma
Travel to or residence of southwestern United States	Coccidioides spp
Travel to or residence of Asia	Burkholderia pseudomallei, severe acute respiratory disease
Influenza active in community	Influenza, S pneumoniae, S aureus, H influenzae
Structural lung disease (eg, bronchiectasis)	Pseudomonas aeruginosa, Burkholderia cepacia, S aureus
Injection drug use	S aureus, S anserobes, M tuberculosis, S pneumoniae
Endobronchial obstruction	Anaerobes, S pneumoiae, H influenzae, S aureus
Recent hospitalization, nursing home residence	DRSP, gram-negative bacilli, S aureus
In context of bioterrorism	Bacillus anthracis (anthrax), Yersinia pestis (plague), F tularensis (Tularemia)