title: [Microscopic diagnosis of Pneumocystis jirovecii pneumonia in bronchoalveolar lavage and oropharyngeal wash samples of immunocompromised patients with pneumonia].
abstract: BACKGROUND
  The diagnosis of Pneumocystis jirovecii pneumonia is based on observation of the microorganism using several staining techniques in respiratory samples, especially bronchoalveolar lavage and induced sputum. Recently, the fungus also has been detected in oropharyngeal wash samples, but only using molecular tests.
  
  
  OBJECTIVE
  The diagnostic yield of two microscopic stains, toluidine blue O and direct fluorescent antibody, was compared in bronchoalveolar lavage and oropharyngeal wash samples for the detection of P. jirovecii in immunocompromised patients with pneumonia.
  
  
  METHODS
  Cross-sectional evaluation diagnostic tests were used in 166 immunosuppressed patients with suspected P. jirovecii. By protocol, bronchoscopic bronchoalveolar lavage and oropharyngeal wash samples were prepared by cytocentrifugation, and slides were stained with toluidine blue and fluorescent antibody. The proportion of positive results from each stain and concordance between them were determined.
  
  
  RESULTS
  Twenty-four cases (14.5%) of P. jirovecii were detected in bronchoalveolar lavage samples. Of them, 21 were positive by both toluidine blue and fluorescent antibody stains, whereas 3 cases were detected by fluorescent antibody alone. None of the 166 oropharyngeal wash samples were positive by either of these techniques. No significant differences were found between proportions from positive results (p=0.63). Concordance (kappa coefficient) between both stains was 0.92 (95% CI: 0.84-1.00).
  
  
  CONCLUSIONS
  Both techniques were useful to diagnose P. jirovecii in bronchoalveolar lavage samples. However, toluidine blue stain did not detect 12% of fluorescent antibody positive cases. Oropharyngeal wash samples do not provide sufficient material for the microscopic identification of this fungus.
authors.affiliation: Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia.
authors.forename: Jenniffer
authors.initials: J
authors.lastname: Rodiño
authors.forename: Nataly
authors.initials: N
authors.lastname: Rincón
authors.forename: Yudy Alexandra
authors.initials: YA
authors.lastname: Aguilar
authors.forename: Zulma Vanessa
authors.initials: ZV
authors.lastname: Rueda
authors.forename: Mariana
authors.initials: M
authors.lastname: Herrera
authors.forename: Lázaro Agustín
authors.initials: LA
authors.lastname: Vélez
mesh_terms: D000328:Adult; D001992:Bronchoalveolar Lavage Fluid / Q000382:microbiology*; D004396:Coloring Agents; D005455:Fluorescent Antibody Technique / Q000379:methods; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008875:Middle Aged; D009960:Oropharynx / Q000382:microbiology*; D045363:Pneumocystis carinii / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis* / Q000382:microbiology*; D014048:Tolonium Chloride
chemical_list: D004396:Coloring Agents; D014048:Tolonium Chloride