Etiology of community-acquired pneumonia in hospitalized patients in chile: the increasing prevalence of respiratory viruses among classic pathogens.
OBJECTIVE
The range and relative impact of microbial pathogens, particularly viral pathogens, as a cause of community-acquired pneumonia (CAP) in hospitalized adults has not received much attention. The aim of this study was to determine the microbial etiology of CAP in adults and to identify the risk factors for various specific pathogens.


METHODS
We prospectively studied 176 patients (mean [+/- SD] age, 65.8 +/- 18.5 years) who had hospitalized for CAP to identify the microbial etiology. For each patient, sputum and blood cultures were obtained as well as serology testing for Mycoplasma pneumoniae and Chlamydophila pneumoniae, urinary antigen testing for Legionella pneumophila and Streptococcus pneumoniae, and a nasopharyngeal swab for seven respiratory viruses.


RESULTS
Microbial etiology was determined in 98 patients (55%). S pneumoniae (49 of 98 patients; 50%) and respiratory viruses (32%) were the most frequently isolated pathogen groups. Pneumococcal pneumonia was associated with tobacco smoking of > 10 pack-years (odds ratio [OR], 2.6; 95% confidence interval [CI], 1.2 to 5.4; p = 0.01). Respiratory viruses were isolated more often in fall or winter (28%; p = 0.011), and as an exclusive etiology tended to be isolated in patients >/= 65 years of age (20%; p = 0.07). Viral CAP was associated with antimicrobial therapy prior to hospital admission (OR, 4.5; 95% CI, 1.4 to 14.6).


CONCLUSIONS
S pneumoniae remains the most frequent pathogen in adults with CAP and should be covered with empirical antimicrobial treatment. Viruses were the second most common etiologic agent and should be tested for, especially in fall or winter, both in young and elderly patients who are hospitalized with CAP.
Díaz
Alejandro
A
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile. Electronic address: alediazf@hotmail.com.
Barria
Paulina
P
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
Niederman
Michael
M
Department of Medicine, Winthrop University Hospital, Mineola, NY.
Restrepo
Marcos I
MI
Department of Medicine, Division of Pulmonary/Critical Care Medicine, and Infectious Diseases, South Texas Veterans Health Care System, San Antonio, TX.
Dreyse
Jorge
J
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
Fuentes
Gino
G
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
Couble
Bernardita
B
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
Saldias
Fernando
F
Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002677:Chile / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000453:epidemiology / Q000209:etiology*; D015897:Comorbidity; D005260:Female; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000453:epidemiology / Q000209:etiology*; D011018:Pneumonia, Pneumococcal / Q000453:epidemiology / Q000209:etiology; D011024:Pneumonia, Viral / Q000453:epidemiology / Q000209:etiology*; D011446:Prospective Studies; D012307:Risk Factors; D012621:Seasons; D012907:Smoking / Q000009:adverse effects