DNA amplification of nasopharyngeal aspirates in rats: A procedure to detect Pneumocystis carinii

Helieh S. Oz, Walter T. Hughes

Research output: Contribution to journalArticlepeer-review

Abstract

The diagnosis of Pneumocystis carinii pneumonia (PCP) requires invasive methods of bronchoalveolar lavage and lung biopsy. In this study, we examined efficacy of polymerase chain reaction (PCR) compared to Giemsa and silver ammoniacal staining to detect P. carinii in easily accessible extrapulmonary sites as well as lung. Samples were collected from lung, nasal and pharyngeal aspirates, gastric contents, urine and blood from dexamethasone treated or untreated virus-free Sprague-Dawley rats. All immunosuppressed lung samples were P. carinii positive by PCR analysis and both stains. Respectively DNA fragments of P. carinii were found in 93%, of nasal and 75% of pharyngeal aspirates, and 0% of sera, urine or gastric aspirates from immunosuppressed rats. However, no P. carinii cysts or trophozoites were found in nasal and pharyngeal aspirates (extrapulmonary sites) by silver ammoniacal or Giemsa staining. In comparison, none of the specimens from immunocompetent rats were PCR positive at any sites tested including the lungs. Therefore, PCR amplification products of nasal and pharyngeal aspirates showed that immunosuppressed rats with PCP can carry P. carinii DNA fragments in their upper respiratory tracts, but immunocompetent animals without PCP, are free of the organism and this suggests an approach to be investigated in humans with PCP.

Original languageEnglish (US)
Pages (from-to)119-121
Number of pages3
JournalMicrobial Pathogenesis
Volume27
Issue number2
DOIs
StatePublished - Aug 1999

Keywords

  • Nasopharyngeal aspirates
  • PCR
  • Pneumocystis carinii pneumonia
  • Rat

ASJC Scopus subject areas

  • Microbiology
  • Infectious Diseases

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