title: Streptococcus pneumoniae antigen in urine: diagnostic usefulness and impact on outcome of bacteraemic pneumococcal pneumonia in a large series of adult patients.
abstract: OBJECTIVE
  Urinary pneumococcal antigen detection provides good results in the diagnosis of pneumococcal pneumonia but has rarely been used in bacteraemic pneumococcal pneumonia and it is not known whether it is associated with outcome in this type of pneumonia. Our objectives were to assess the usefulness of an immunochromatographic technique for detecting the pneumococcal antigen in urine in a large prospective study of patients with bacteraemic pneumococcal pneumonia and explore any potential association with outcomes.
  
  
  METHODS
  This study, carried out over 8 years, included all adult immunocompetent patients admitted for bacteraemic pneumococcal pneumonia. An immunochromatographic test for the Streptococcus pneumoniae antigen in urine was performed in the first 24 h. The sensitivity of test was assessed and patients were divided into two groups according to test results to explore differences on admission and during the course of the illness using logistic regression models.
  
  
  RESULTS
  Of the 350 patients with bacteraemic pneumococcal pneumonia included, 261 (74.6%) were positive for the antigen. Patient characteristics were very similar on admission and differences in severity (Pneumonia Severity Index) were not statistically significant. In the adjusted analysis, antigen-positive patients had a higher risk of intensive care unit admission, treatment failure and adverse outcome.
  
  
  CONCLUSIONS
  The sensitivity of the immunochromatographic urinary antigen test was 74.6% and positive results were associated with poorer clinical outcome. We therefore recommend systematic use of this test when pneumonia is diagnosed in the emergency department.
authors: Department of Respiratory Medicine, Cruces University Hospital, Barakaldo, Bizkaia, Spain.
authors: Rafael
authors: R
authors: Zalacain
authors: Alberto
authors: A
authors: Capelastegui
authors: Luis Alberto
authors: LA
authors: Ruiz
authors: Amaia
authors: A
authors: Bilbao
authors: Ainhoa
authors: A
authors: Gomez
authors: Ane
authors: A
authors: Uranga
authors: Pedro P
authors: PP
authors: España
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000942:Antigens, Bacterial / Q000652:urine*; D016470:Bacteremia / Q000175:diagnosis* / Q000276:immunology / Q000652:urine; D015415:Biomarkers / Q000652:urine; D002846:Chromatography, Affinity / Q000379:methods*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011018:Pneumonia, Pneumococcal / Q000175:diagnosis* / Q000276:immunology / Q000652:urine; D011379:Prognosis; D011446:Prospective Studies; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013296:Streptococcus pneumoniae / Q000276:immunology*
chemical_list: D000942:Antigens, Bacterial; D015415:Biomarkers
keywords: bacteraemic pneumococcal pneumonia; community-acquired pneumonia; outcome; sensitivity; urinary pneumococcal antigen