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The
Etiology of Community-Acquired Pneumonia at an Urban Public Hospital:
Influence of Human Immunodeficiency Virus Infection and Initial
Severity of Illness [Park DR et al. JID 2001;184:268]
The authors report a prospective study of 522 patients with community-acquired
pneumonia at Harborview Hospital in Seattle for 1994-96. The diagnostic
studies included expectorated sputum Gram stain and culture, serology
for atypical strains, and nasopharyngeal swabs for respiratory viruses.
Of the 522 participants, 112 had HIV infection, including 67% with
a CD4 cell count <200/mm3.
Demographics of participants reflected the population of an urban
tertiary care center, with high rates of racial minorities, homeless
and uninsured patients, and substance abusers. The mortality rate
was 5% (25 patients), which was significantly higher in those with
HIV infection (8.9% vs. 3.7%). With regard to microbiology, HIV-infected
patients had a significantly higher rate of pneumonia caused by
M. tuberculosis, P. carinii and P. aeruginosa.
Details are provided in the table below:
|
Microbial
Cause of Community-Acquired Pneumonia
|
| |
HIV
neg
n = 410 |
HIV
pos
n= 112 |
| Bacteria |
|
S. pneumoniae |
46
(11%) |
8
(7%) |
|
H. influenzae |
20
(5%) |
2
(2%) |
|
S. aureus |
10
(2%) |
4
(4%) |
|
GNB |
4
(1%) |
4
(4%)* |
|
Mycoplasma |
29
(7%) |
8
(7%) |
|
C. pneumoniae |
23
(6%) |
2
(2%) |
|
Legionella |
32
(8%) |
5
(5%) |
|
M. tuberculosis |
21
(5%) |
13
(12%)* |
| Fungi
P. carinii |
0 |
35
(31%)* |
| Viruses |
3
(1%) |
3
(3%)* |
| Aspiration |
65
(16%) |
3
(3%) |
| Unknown |
190
(46%) |
39
(35%) |
|
*p = < 0.05 for difference |
Comment:
The results of this study are similar to those reported previously
by others, including the unique display of pathogens for patients
with HIV infection [Am J Resp Crit Care Med 1995;152:1309].
As with most comprehensive microbiology studies, nearly 50% had
no identifiable pathogen. The dominant pathogens among those without
HIV infection were S. pneumoniae, atypicals, and aspiration;
for those with HIV infection, the major pathogen was P. carinii
followed by tuberculosis and S. pneumoniae. The authors
of the report conclude that their study shows the "importance
of recognizing underlying HIV infection in patients who were hospitalized
with CAP," and they also point out some of the unique features
of the HIV-infected population including the differences noted above,
but also the infrequency of Legionella and the potential importance
of P. aeruginosa.
posted
8/14/2001
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