title: Aetiology and risk factors of community-acquired pneumonia in hospitalized patients in Norway.
abstract: OBJECTIVE
  In Norway, data on the aetiology of community-acquired pneumonia (CAP) in hospitalized patients are limited. The aims of this study were to investigate the bacterial aetiology of CAP in hospitalized patients in Norway, risk factors for CAP and possible differences in risk factors between patients with Legionnaire's disease and pneumonia because of other causes.
  
  
  METHODS
  Adult patients with radiologically confirmed CAP admitted to hospital were eligible for the study. Routine aerobic and Legionella culture of sputum, blood culture, urinary antigen test for Legionella pneumophila and Streptococcus pneumoniae, polymerase chain reaction detection of Chlamydophila pneumoniae, Mycoplasma pneumoniae and Bordetella pertussis from throat specimens, and serology for L. pneumophila serogroup 1-6 were performed. A questionnaire, which included demographic and clinical data, risk factors and treatment, was completed.
  
  
  RESULTS
  We included 374 patients through a 20-month study period in 2007-2008. The aetiological agent was detected in 37% of cases. S. pneumoniae (20%) was the most prevalent agent, followed by Haemophilus influenzae (6%) and Legionella spp. (6%). Eight Legionella cases were diagnosed by urinary antigen test, of which four also had positive serology. In addition, 13 Legionella cases were diagnosed by serology. The degree of comorbidity was high. An increased risk of hospital-diagnosed Legionella pneumonia was found among patients with a diagnosis of chronic congestive heart failure.
  
  
  CONCLUSIONS
  Our results indicate that S. pneumoniae is the most common bacterial cause of pneumonia in hospitalized patients, and the prevalence of Legionella pneumonia is probably higher in Norway than recognized previously.
authors.affiliation: Department of Occupational and Environmental Medicine, Telemark Hospital, Skien, Norway. wenche.roysted@sthf.no.
authors.forename: Wenche
authors.initials: W
authors.lastname: Røysted
authors.affiliation: Clinic of Internal Medicine, Østfold Hospital Trust, Fredrikstad, Norway.
authors.forename: Øystein
authors.initials: Ø
authors.lastname: Simonsen
authors.affiliation: Unilabs Telelab AS, Skien, Norway.|Department of Environmental and Health Sciences, Telemark University College, Bø, Telemark, Norway.
authors.forename: Andrew
authors.initials: A
authors.lastname: Jenkins
authors.affiliation: Department of Medicine, Telemark Hospital, Skien, Norway.
authors.forename: Marjut
authors.initials: M
authors.lastname: Sarjomaa
authors.affiliation: Department of Occupational and Environmental Medicine, Telemark Hospital, Skien, Norway.
authors.forename: Martin Veel
authors.initials: MV
authors.lastname: Svendsen
authors.affiliation: Center for Laboratory Medicine, Østfold Hospital Trust, Fredrikstad, Norway.
authors.forename: Eivind
authors.initials: E
authors.lastname: Ragnhildstveit
authors.affiliation: Department of Medical Microbiology, Unilabs Telelab AS, Skien, Norway.|Department of Medical Biochemistry, Telemark Hospital, Skien, Norway.
authors.forename: Yngvar
authors.initials: Y
authors.lastname: Tveten
authors.affiliation: Center for Laboratory Medicine, Østfold Hospital Trust, Fredrikstad, Norway.
authors.forename: Anita
authors.initials: A
authors.lastname: Kanestrøm
authors.affiliation: Department of Research and Development, Telemark Hospital, Skien, Norway.
authors.forename: Halfrid
authors.initials: H
authors.lastname: Waage
authors.affiliation: Clinic of Internal Medicine, Østfold Hospital Trust, Fredrikstad, Norway.
authors.forename: Jetmund
authors.initials: J
authors.lastname: Ringstad
mesh_terms: D000328:Adult; D000368:Aged; D017714:Community-Acquired Infections / Q000453:epidemiology* / Q000382:microbiology; D005260:Female; D006090:Gram-Negative Bacteria / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006094:Gram-Positive Bacteria / Q000302:isolation & purification; D016908:Gram-Positive Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D006760:Hospitalization; D006801:Humans; D008297:Male; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D055815:Young Adult
keywords: Legionella; Norway; bacterial pneumonia; community-acquired infections; risk factors