title: Improvement of pneumococcal pneumonia diagnostics by the use of rt-PCR on plasma and respiratory samples.
abstract: BACKGROUND
  The aim of the study was to assess the performance of a real-time polymerase chain reaction (rt-PCR) assay on plasma and respiratory samples for the diagnosis of pneumococcal pneumonia.
  
  
  METHODS
  Three hundred and forty patients (160 children and 180 adults) with community-acquired pneumonia were included prospectively from January 2011 to May 2012. Blood samples were obtained simultaneously for culture and rt-PCR targeting the lytA gene. Respiratory samples were also obtained: nasopharyngeal swab in nearly all patients and sputum or tracheal aspirate when available.
  
  
  RESULTS
  Streptococcus pneumoniae was detected in 222 (65%) of 340 patients: 143 (89%) children and 79 (44%) adults. Pneumonia was assigned as definite pneumococcal in 96 (28.2%) of 340 patients, according to S. pneumoniae detected in blood: in 54 (33.8%) children - by rt-PCR in 51 (31.9%) and by culture in 5 (3.1%); and in 42 (23.3%) adults - by rt-PCR in 41 (22.8%) and by culture in 12 (6.7%). Pneumonia was considered as probably pneumococcal in 19 (10.6%) adults according to S. pneumoniae detected in sputum/tracheal aspirate, by rt-PCR in 19 and by culture in 5. In 18 adults and 89 children with S. pneumoniae detected only in the nasopharynx, pneumonia was considered as possibly pneumococcal; however it should be noted that nasopharyngeal colonization with S. pneumoniae is also common in children with other aetiologies of pneumonia.
  
  
  CONCLUSIONS
  rt-PCR on plasma and other samples performed significantly better than culture for the detection of pneumococcal pneumonia (p < 0.0005) in children and adults.
authors.affiliation: From the Institute of Microbiology and Immunology, Faculty of Medicine, University of Ljubljana.
authors.forename: Vesna
authors.initials: V
authors.lastname: Cvitkovic Spik
authors.forename: Bojana
authors.initials: B
authors.lastname: Beovic
authors.forename: Marko
authors.initials: M
authors.lastname: Pokorn
authors.forename: Ana
authors.initials: A
authors.lastname: Drole Torkar
authors.forename: Darja
authors.initials: D
authors.lastname: Vidmar
authors.forename: Lea
authors.initials: L
authors.lastname: Papst
authors.forename: Katja
authors.initials: K
authors.lastname: Seme
authors.forename: Rok
authors.initials: R
authors.lastname: Kogoj
authors.forename: Manica
authors.initials: M
authors.lastname: Müller Premru
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001426:Bacterial Proteins / Q000235:genetics; D001431:Bacteriological Techniques / Q000379:methods; D002675:Child, Preschool; D017714:Community-Acquired Infections / Q000175:diagnosis / Q000382:microbiology; D004269:DNA, Bacterial / Q000235:genetics; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009305:Nasopharynx / Q000382:microbiology; D010949:Plasma / Q000382:microbiology*; D011018:Pneumonia, Pneumococcal / Q000175:diagnosis* / Q000382:microbiology; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013183:Sputum / Q000382:microbiology*; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*; D055815:Young Adult
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial