Pneumocystis jirovecii genotyping: experience in a tertiary-care hospital in Northern Italy

Respiratory samples from Pneumocystis jirovecii pneumonia (PJP) cases collected at a tertiary-care university hospital in Modena were analyzed for the presence of specific polymorphisms in the mitochondrial large subunit ribosomal RNA (mtLSU-rRNA). Retrospectively, 57 cases were selected in a six-year period and 34 out of the 57 processed BAL samples returned PCR positive results, thus allowing further molecular analysis. The following P.jirovecii genotype distribution was observed: genotype 3 (50%), genotype 2 (23%), genotype 1 (18%), genotypes 1 or 4 (9%). These data add novel insights on P.jirovecii epidemiology, investigating a previously unstudied area of Northern Italy. A peculiar local distribution is highlighted with respect to other areas within the national panorama, thus encouraging further in-depth studies in an attempt to better understand the overall situation concerning P.jirovecii genotype circulation.

Detection of Pneumocystis jirovecii and Aspergillus spp. DNa in bronchoalveolar lavage fluids by commercial real-time PCr assays: comparison with conventional diagnostic tests

The present study employed two commercial real-time PCR kits, MycAssay� Pneumocystis (PJ-PCR) and MycAssay� Aspergillus (ASP-PCR), for the search of fungal DNA on 44 bronchoalveolar lavage (BAL) fluids from patients at risk of invasive fungal disease. Operationally, on the basis of clinical diagnosis and according to the European Organization for Research and Treatment Cancer/Mycoses Study Group (EORTC/MSG) criteria, patients were clustered in 3 groups: a P. jirovecii pneumonia (PCP) group, an invasive aspergillosis (IA) group and a control (CTRL) group, consisting of 8, 10 and 24 patients, respectively. The results were compared to those obtained with conventional diagnostic assays, including BAL culture, galactomannan-ELISA (GM) and immunofluorescence (IF). The PJ-PCR assay returned a sensitivity and specificity of 100% and 94.4%, respectively. The ASP-PCR assay showed a sensitivity and specificity of 80% and 97.1%. When compared to the culture assay, the ASP-PCR showed enhanced sensitivity, and a good level of agreement (kappa = 0.63) was observed between ASP-PCR and GM assays. Overall, our data emphasize the diagnostic usefulness of the two commercial real-time PCR assays, especially in high-risk patients where timing is critical and a low fungal burden may hamper correct and prompt diagnosis by conventional tests.