title: Community-acquired pneumonia in Chile: the clinical relevance in the detection of viruses and atypical bacteria.
abstract: BACKGROUND
  Adult community-acquired pneumonia (CAP) is a relevant worldwide cause of morbidity and mortality, however the aetiology often remains uncertain and the therapy is empirical. We applied conventional and molecular diagnostics to identify viruses and atypical bacteria associated with CAP in Chile.
  
  
  METHODS
  We used sputum and blood cultures, IgG/IgM serology and molecular diagnostic techniques (PCR, reverse transcriptase PCR) for detection of classical and atypical bacteria (Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella pneumoniae) and respiratory viruses (adenovirus, respiratory syncytial virus (RSV), human metapneumovirus, influenza virus, parainfluenzavirus, rhinovirus, coronavirus) in adults >18 years old presenting with CAP in Santiago from February 2005 to September 2007. Severity was qualified at admission by Fine's pneumonia severity index.
  
  
  RESULTS
  Overall detection in 356 enrolled adults were 92 (26%) cases of a single bacterial pathogen, 80 (22%) cases of a single viral pathogen, 60 (17%) cases with mixed bacterial and viral infection and 124 (35%) cases with no identified pathogen. Streptococcus pneumoniae and RSV were the most common bacterial and viral pathogens identified. Infectious agent detection by PCR provided greater sensitivity than conventional techniques. To our surprise, no relationship was observed between clinical severity and sole or coinfections.
  
  
  CONCLUSIONS
  The use of molecular diagnostics expanded the detection of viruses and atypical bacteria in adults with CAP, as unique or coinfections. Clinical severity and outcome were independent of the aetiological agents detected.
authors.affiliation: Programa de Virología, Facultad de Medicina, Universidad de Chile, , Santiago, Chile.
authors.forename: Vivian
authors.initials: V
authors.lastname: Luchsinger
authors.forename: Mauricio
authors.initials: M
authors.lastname: Ruiz
authors.forename: Enna
authors.initials: E
authors.lastname: Zunino
authors.forename: María Angélica
authors.initials: MA
authors.lastname: Martínez
authors.forename: Clarisse
authors.initials: C
authors.lastname: Machado
authors.forename: Pedro A
authors.initials: PA
authors.lastname: Piedra
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Fasce
authors.forename: María Teresa
authors.initials: MT
authors.lastname: Ulloa
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Fink
authors.forename: Pamela
authors.initials: P
authors.lastname: Lara
authors.forename: Mónica
authors.initials: M
authors.lastname: Gebauer
authors.forename: Fernando
authors.initials: F
authors.lastname: Chávez
authors.forename: Luis F
authors.initials: LF
authors.lastname: Avendaño
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001419:Bacteria / Q000235:genetics*; D002677:Chile / Q000453:epidemiology; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000453:epidemiology*; D004269:DNA, Bacterial / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D018410:Pneumonia, Bacterial / Q000175:diagnosis / Q000453:epidemiology* / Q000382:microbiology; D011024:Pneumonia, Viral / Q000175:diagnosis / Q000453:epidemiology* / Q000821:virology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013183:Sputum / Q000382:microbiology / Q000821:virology; D014780:Viruses / Q000235:genetics*; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D004279:DNA, Viral
keywords: Bacterial Infection; Pneumonia; Respiratory Infection; Viral infection