title: Pleural effusion with negative culture: a challenge for pneumococcal diagnosis in children.
abstract: BACKGROUND
  Pneumococcal parapneumonic effusion seems to be increasing in children in the postvaccine era and is frequently associated with negative culture. Due to the low yield of culture, culture-independent tools are evaluated.
  
  
  METHODS
  Culture-negative pleural fluid specimens from 38 children with parapneumonic effusion were examined for pneumococcal lytA by quantitative polymerase chain reaction (qPCR) and soluble antigen (C-polysaccharide) using an immunochromatographic test (BinaxNow Streptococcus pneumoniae).
  
  
  RESULTS
  In 81% (30/37) and 63% (24/38) of the specimens, a positive result was obtained by qPCR and antigen detection, respectively. Most mismatches were observed in specimens with low quantities of pneumococcal DNA and a negative antigen test.
  
  
  CONCLUSIONS
  Our results suggest an imperfect relationship between the 2 described methods. The immunochromatographic assay is a simple diagnostic tool, which can be used when resources are limited, and even after antibiotic use, but negative results may require confirmation through a more sensitive test, such as qPCR.
authors.affiliation: Universidade Federal de Ciências da Saúde de Porto Alegre, Sarmento Leite Street 245, Microbiologia, Chamber 202, 90050-270, Porto Alegre, RS, Brazil. Electronic address: vinicius.perez@metodistadosul.edu.br.
authors.forename: Vinicius Pieta
authors.initials: VP
authors.lastname: Perez
authors.affiliation: Universidade Federal de Ciências da Saúde de Porto Alegre, Sarmento Leite Street 245, Microbiologia, Chamber 202, 90050-270, Porto Alegre, RS, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Caierão
authors.affiliation: Hospital da Criança Santo Antônio da Santa Casa de Porto Alegre, Independência avenue 155, Pneumologia Pediátrica, 90020-090, Porto Alegre, RS, Brazil.
authors.forename: Gilberto Bueno
authors.initials: GB
authors.lastname: Fischer
authors.affiliation: Universidade Federal de Ciências da Saúde de Porto Alegre, Sarmento Leite Street 245, Microbiologia, Chamber 202, 90050-270, Porto Alegre, RS, Brazil.
authors.forename: Cícero Armídio Gomes
authors.initials: CA
authors.lastname: Dias
authors.affiliation: Universidade Federal de Ciências da Saúde de Porto Alegre, Sarmento Leite Street 245, Microbiologia, Chamber 202, 90050-270, Porto Alegre, RS, Brazil.
authors.forename: Pedro Alves
authors.initials: PA
authors.lastname: d'Azevedo
mesh_terms: D000293:Adolescent; D001431:Bacteriological Techniques / Q000379:methods*; D002648:Child; D002675:Child, Preschool; D002846:Chromatography, Affinity / Q000379:methods*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D010996:Pleural Effusion / Q000175:diagnosis* / Q000382:microbiology; D011008:Pneumococcal Infections / Q000175:diagnosis* / Q000382:microbiology; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D013296:Streptococcus pneumoniae / Q000302:isolation & purification*
keywords: C-polysaccharide; Empyema; Pleural effusion; Real-time PCR; Streptococcus pneumoniae