Investigation of Pneumocystis jirovecii Colonization in Patients with Pulmonary Diseases

Objective : The detection of Pneumocystis jirovecii or its DNA in respiratory samples from individuals who do not have signs or symptoms of pneumonia has been defined as colonization. In this study, we aimed to investigate the prevalence of P. jirovecii colonization in patients with various lung diseases. Methods : Thirty patients who were followed-up and who had undergone bronchoscopy for diagnosis of different underlying diseases or pulmonary signs were included in the study. Bronchoalveolar lavage (BAL) fluids of these patients were analyzed with nPCR amplification of the mt-LSUrRNA gene of P. jirovecii. In addition to nPCR, giemsa, Gomori's methenamine silver (GMS), and indirect fluorescence antibody (IFA) staining assays were applied to all samples. Results : P. jirovecii DNA was detected in 21 of 30 (70%) BAL samples by nPCR. However, P. jirovecii cysts were found in 1 of 21 nPCR-positive samples by giemsa and GMS. IFA assay showed six samples to be positive, but only four of them were found to be positive by nPCR. Conclusion : Result of our study showed that prevalence of P. jirovecii colonization is particularly high in patients with chronic pulmonary diseases, and nPCR was a good assay for evaluation of the colonization of P. jirovecii.