Outcome of Pneumocystis jirovecii pneumonia diagnosed by polymerase chain reaction in patients without human immunodeficiency virus infection

Background and objective: Pneumonia caused by Pneumocystis jirovecii (PCP) in patients without human immunodeficiency virus (HIV) infection is associated with high mortality. The diagnosis of PCP at our institution is based on detection of DNA using a polymerase chain reaction (PCR) assay. The aim of this study was to describe the clinical manifestations, outcomes and factors associated with mortality due to PCP, as diagnosed by PCR, in patients without HIV infection. Methods: Over a 6-year period, all HIV-negative immunocompromised patients suspected of having an opportunistic pulmonary infection underwent diagnostic bronchoscopy. A multigene PCR assay that detects Pneumocystis jirovecii DNA was used for the diagnosis of PCP. Patients were considered to have PCP if they had underlying immunodeficiency, compatible signs and symptoms, abnormal radiological findings, and Pneumocystis jiroveciiDNAwas detected in a bronchoalveolar lavage fluid sample. Data was collected retrospectively. Results: PCP was diagnosed in 58 patients. The underlying conditions included haematological malignancies (60.3%), solid tumours (17.2%) and immunosuppressive treatment (22.4%). The most common clinical features in patients with PCP were fever (94.6%), dyspnoea (67.2%) and cough (36.2%). The overall in-hospital mortality was 17.2% (10/ 58). Mortality was associated with co-infections, high lactate dehydrogenase levels, female gender, and higher pneumonia severity index and acute physiology and chronic health evaluation III scores. Conclusions: In this study, the mortality of HIVnegative patients with PCP was lowcompared with previous reports. We hypothesize that this finding resulted from the increased sensitivity of a PCR-based assay, as compared with traditional methods, for the diagnosis of PCP in HIV-negative patients.