Comparison between real-time PCR, conventional PCR and different staining techniques for diagnosing Pneumocystis jiroveci pneumonia from bronchoalveolar lavage specimens

Laboratory of Parasitology and Mycology, Hôpital Nord 1 and Department of Infectious and Tropical Diseases, Hôpital Bellevue 2 , University Hospital of Saint Etienne, 42055 Saint Etienne, France Correspondence Pierre Flori pierre.flori{at}univ-st-etienne.fr Received November 7, 2003 Accepted February 10, 2004 Between January 2002 and July 2003, 173 bronchoalveolar lavage (BAL) specimens from 150 patients (19 HIV-infected and 131 non-HIV-infected patients) were evaluated for identification of Pneumocystis jiroveci (formerly known as Pneumocystis carinii f. sp. hominis ) using staining techniques, conventional PCR ( mtLSUrRNA gene) and real-time PCR ( MSG gene). Test results were compared to Pneumocystis pneumonia (PCP) confirmed by typical clinical findings and response to treatment. Sensitivity and specificity of the techniques were 60 and 100 % for staining (where either one or both techniques were positive), 100 and 87.0 % for conventional PCR and 100 and 84.9 % for real-time PCR, respectively. The use of a concentration of 10 3 copies of DNA per capillary of BAL as a cut-off (determined by real-time PCR) increased specificity from 84.9 to 98.6 % without reducing the sensitivity of the technique. This technique is rapid (