Table 2.

Etiology of common community-acquired pneumonia in HIV-infected patients

Etiology	Area of endemicity	Incidence	Risk factors
Bacterial	Ubiquitous	1.9–19.2 cases/ 100 patient-years	Decreasing CD4 cell counts, injection drug use, prior sinusitis and respiratory tract infection, use of TMP-SMXd
Mycobacterial	Ubiquitous	1.4–16.2 cases/ 100 patient-years	Injection drug use, homeless, PPD skin test positive
Opportunistic fungal infections
Pneumocystis jeroveci	Ubiquitous	0.22–4.6 cases/ 100 patient-years	CD4 <200 cells/mm3, clinical markere, the occurrence of previous pneumonia and AIDS-defining illness
Cryptococcus neoformans	Ubiquitous	ND	CD4 <100 cells/mm3, black race, injection drug use, cigarette smoking
Histoplasma capsulatum	North American river valleys, Europe, Africa, Southeast Asia, Caribbean, Central and South America Argentina, Central America	1%–25%a	Age, underlying immunosuppression
Coccidioides immitis	Southwestern United States, Northwestern Mexico	0.3%–8.2%b	CD4 <250 cells/mm3, clinical diagnosis of AIDS
Penicillium marnefeii	Southern China, Hong Kong, Thailand, Vietnam	15%–20%c	Exposure to environmental reservoirsf

Abbreviations: ND, no data; PPD, purified protein derivative; TMP-SMX, trimethoprim-sulfamethoxazole.

^aIncidence varies from <1% of patients in nonendemic areas to 25% of patients in endemic areas.

^bIncidence varies from 0.3% nationwide (United States) to 8.2% in Arizona.

^cAccounting for 15% to 20% of all AIDS-related illness in Northern Thailand.

^dThis factor was found to be protective.

^eIncluding wasting syndrome, the occurrence of a previous episode of pneumonia of any type, or the occurrence of previous AIDS-defining events.

^fOccupational or other exposure to soil in Northern Thailand.