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Published on: February 15, 2013

Detection of Pneumocystis DNA in samples from patients suspected of bacterial pneumonia--a case-control study

Jannik Helweg-Larsen1, Jørgen Skov Jensen, Birthe Dohn

  • 1Copenhagen HIV Programme, Department of Infectious Diseases, Copenhagen, Denmark. jhl@cphiv.dk

BMC Infectious Diseases
|November 26, 2002
PubMed
Abstract

Insights

Pneumocystis jiroveci (PJP) DNA detection in HIV-uninfected patients with suspected bacterial pneumonia is linked to older age, comorbidities, and steroid use. This finding suggests PJP PCR has low specificity for diagnosing PJP pneumonia in non-immunocompromised individuals.

Area of Science:

  • Medical Mycology
  • Infectious Diseases
  • Clinical Microbiology

Background:

  • Pneumocystis jiroveci is an opportunistic fungus causing Pneumocystis pneumonia (PCP) in immunocompromised individuals.
  • Polymerase chain reaction (PCR) is a method for detecting Pneumocystis jiroveci.
  • The clinical significance of positive Pneumocystis-PCR in HIV-uninfected patients with suspected bacterial pneumonia requires investigation.

Purpose of the Study:

  • To evaluate the clinical importance of positive Pneumocystis-PCR results in HIV-uninfected patients presenting with symptoms suggestive of bacterial pneumonia.
  • To identify clinical factors associated with Pneumocystis jiroveci carriage in this patient population.

Main Methods:

  • A retrospective matched case-control study was conducted.
  • Respiratory samples from 367 patients suspected of bacterial pneumonia were analyzed using PCR for Pneumocystis jiroveci.
  • PCR-positive cases were matched with four PCR-negative controls based on sex and date of birth.

Main Results:

  • Pneumocystis-DNA was detected in 4.4% of patients.
  • PCR-positive patients were older (median 74 vs. 62 years) and had a higher prevalence of severe concomitant illness (94% vs. 50%).
  • Corticosteroid treatment was significantly more common in PCR-positive cases (75% vs. 13%).
  • A worse prognosis was observed in PCR-positive patients, with a 30-day mortality rate of 44% compared to 14% in controls.

Conclusions:

  • Pneumocystis jiroveci carriage in HIV-uninfected patients is associated with advanced age, concurrent severe diseases, and corticosteroid therapy.
  • PCR detection of Pneumocystis jiroveci demonstrates low specificity for diagnosing PCP in patients without known immunodeficiency.
  • Further research is needed to clarify whether the poorer prognosis is due to overt infection or subclinical carriage, particularly in patients on systemic corticosteroids.

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