Background and Objectives: With increasing rate of immunodeficiency diseases in the world, opportunistic micro-organism such as Pneumocystis jirovecii (P. jirovecii) become more important. Little information is available on prevalence of this life- threatening microorganism in Iran. This study was designed to determine the colonization and the rate of active disease caused by P. jirovecii in two groups of Iranian immunosuppressed patients.
Materials and Methods: Two hundred and fifty five pulmonary samples were collected from two groups of immunosuppress- ed patients to detect a 260bp fragment of mt LSU rRNA gene of P. jirovecii by nested PCR. The first group was COPD patients consumed oral, inhaled or injectable corticosteroid and the second group was patients with malignancies under chemotherapy. Both groups were referred to National Research Institute of Tuberculosis and Lung Disease and Imam Khomeini hospital because of pulmonary symptoms. All patients introduced to this project were confirmed HIV sera-negative by ELISA and western blot test.
Results: The mean age of COPD patients was 66.5 ± 11 (41-88) years and all of them were men. The mean age of patients with malignancy (PMs) was 43 ± 11 (23-65) years and 51.6% were men. The P. jirovecii was colonized in 7 of 89 COPD patients (7.9%) and its DNA was isolated from 11 of 153 PMs (7.2%). The microorganism could cause active disease in 7 of 67 (10.5%) PMs who suffered from pneumonia.
Conclusion: The study showed that P. jirovecii was one of colonizing agents in the COPD patients, but it could cause active disease in PMs. Generally, the microorganism can exist in the lung of non-HIV+ immunosuppressed patients. Therefore, it should be considered as a potential infective agent in non-HIV+ immunocompromised patients.