title: Etiology of community-acquired pneumonia in hospitalized patients in chile: the increasing prevalence of respiratory viruses among classic pathogens.
abstract: 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.
authors.affiliation: Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile. Electronic address: alediazf@hotmail.com.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Díaz
authors.affiliation: Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Paulina
authors.initials: P
authors.lastname: Barria
authors.affiliation: Department of Medicine, Winthrop University Hospital, Mineola, NY.
authors.forename: Michael
authors.initials: M
authors.lastname: Niederman
authors.affiliation: Department of Medicine, Division of Pulmonary/Critical Care Medicine, and Infectious Diseases, South Texas Veterans Health Care System, San Antonio, TX.
authors.forename: Marcos I
authors.initials: MI
authors.lastname: Restrepo
authors.affiliation: Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Jorge
authors.initials: J
authors.lastname: Dreyse
authors.affiliation: Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Gino
authors.initials: G
authors.lastname: Fuentes
authors.affiliation: Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Bernardita
authors.initials: B
authors.lastname: Couble
authors.affiliation: Departamento de Enfermedades Respiratorias, Pontificia Universidad Católica de Chile, Santiago, Chile.
authors.forename: Fernando
authors.initials: F
authors.lastname: Saldias
mesh_terms: 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