title: Diagnosis of Pneumocystis jirovecii pneumonia in immunocompromised patients by real-time PCR: a 4-year prospective study.
abstract: Pneumocystis jirovecii pneumonia (PCP) is a life-threatening infection in immunocompromised patients. Quantitative real-time PCR (qPCR) is more sensitive than microscopic examination for the detection of P. jirovecii but also detects colonized patients. Hence, its positive predictive value (PPV) needs evaluation. In this 4-year prospective observational study, all immunocompromised patients with acute respiratory symptoms who were investigated for PCP were included, totaling 659 patients (814 bronchoalveolar lavage fluid samples). Patients with negative microscopy but positive qPCR were classified through medical chart review as having retained PCP, possible PCP, or colonization, and their clinical outcomes were compared to those of patients with microscopically proven PCP. Overall, 119 patients were included for analysis, of whom 35, 41, and 43 were classified as having retained PCP, possible PCP, and colonization, respectively. The 35 patients with retained PCP had clinical findings similar to those with microscopically proven PCP but lower fungal loads (P < 0.001) and were mainly non-HIV-infected patients (P < 0.05). Although the mean amplification threshold was higher in colonized patients, it was not possible to determine a discriminant qPCR cutoff. The PPV of qPCR in patients with negative microscopy were 29.4% and 63.8% when considering retained PCP and retained plus possible PCP, respectively. Patients with possible PCP had a higher mortality rate than patients with retained PCP or colonization (63% versus 3% and 16%, respectively); patients who died had not received co-trimoxazole. In conclusion, qPCR is a useful tool to diagnose PCP in non-HIV patients, and treatment might be better targeted through a multicomponent algorithm including both clinical/radiological parameters and qPCR results.
authors.affiliation: Service of Parasitology and Mycology, Centre Hospitalier Universitaire de Rennes, Rennes, France INSERM U1085-IRSET, Université Rennes 1, Rennes, France florence.robert-gangneux@univ-rennes1.fr.
authors.forename: Florence
authors.initials: F
authors.lastname: Robert-Gangneux
authors.affiliation: Service of Parasitology and Mycology, Centre Hospitalier Universitaire de Rennes, Rennes, France INSERM U1085-IRSET, Université Rennes 1, Rennes, France.
authors.forename: Sorya
authors.initials: S
authors.lastname: Belaz
authors.affiliation: Service of Infectious Diseases, Centre Hospitalier Universitaire de Rennes, Rennes, France.
authors.forename: Matthieu
authors.initials: M
authors.lastname: Revest
authors.affiliation: Service of Infectious Diseases, Centre Hospitalier Universitaire de Rennes, Rennes, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Tattevin
authors.affiliation: INSERM U1085-IRSET, Université Rennes 1, Rennes, France Service of Pneumology, Centre Hospitalier Universitaire de Rennes, Rennes, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Jouneau
authors.affiliation: Department of Internal Medicine, Centre Hospitalier Universitaire de Rennes, Rennes, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Decaux
authors.affiliation: INSERM U1085-IRSET, Université Rennes 1, Rennes, France.
authors.forename: Sylviane
authors.initials: S
authors.lastname: Chevrier
authors.affiliation: Intensive Care Unit, Centre Hospitalier Universitaire de Rennes, Rennes, France.
authors.forename: Yves
authors.initials: Y
authors.lastname: Le Tulzo
authors.affiliation: Service of Parasitology and Mycology, Centre Hospitalier Universitaire de Rennes, Rennes, France INSERM U1085-IRSET, Université Rennes 1, Rennes, France.
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Gangneux
mesh_terms: D000368:Aged; D005260:Female; D006801:Humans; D016867:Immunocompromised Host; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D045363:Pneumocystis carinii / Q000302:isolation & purification*; D011020:Pneumonia, Pneumocystis / Q000175:diagnosis* / Q000382:microbiology / Q000473:pathology; D011446:Prospective Studies; D011859:Radiography; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*