Molecular diagnosis of Pneumocystis jirovecii pneumonia by using External PCR in immunocompromised patients .

Abstract

Pneumocystis jirovecii is an opportunistic eukaryotic pathogen causing life threating pneumonia ( PJP) in immunosuppressed patients.Detection of Pneumocystis jirovecii Pneumonia in immune suppressed patients like hematological cancer with or without chemotherapy, patients on corticosteroid therapy, other malignancy like bronchogenic cancer by using External Polymerase Chain Reaction (External PCR) and to compare the results with other control group (patients who are immunocompetent suffer from pneumonia).A total of 220 specimens were obtained from patients admitted to Al- Ramadi Teaching Hospital, Clinic excitability of respiratory disease in Al- Ramadi and Oncology Teaching Hospital in Baghdad during the period from February to July 2013. This number composed of 71(32%) specimens were from female while the male specimens were 149(68%). A total of 184 (84%) were immunocompromised patients, They were considered immunocompromised patients because they have ( hematological cancer with or without chemotherapy, patients on corticosteroid therapy, other malignancies like bronchogenic cancer). The other 36 (16%) patients with pneumonia were included as immunocompetent patients (No hematological cancer, No chemotherapy, No immunosuppressive drug like corticosteroid therapy and No malignancy like bronchogenic cancer). A total of 220 specimens which were collected, (consisting of 115 blood, 65 sputum, 40 BAL Specimens )the total 220 specimens (115 blood, 65 sputum and 40 BAL Specimens ) were examined PCR technique ( External and Nested PCR ) to identify Pneumocystis Jirovecii DNA based on the amplification of specific primers. The result of agarose gel electrophoresis revealed that small DNA diagnostic bands were detected at 346 bp for External PCR in all positive specimens. Out of 220 specimens 26 (11.8%) were detected by the mtLSU rRNA External PCR. Regarding the use of External PCR technique for sputum specimens 8 (12.3%) were positive, While BAL 8 (20%) and Blood 10 (8.7%) . PCR is more accurate and better indicative for the presence of Pneumocystis jirovecii Pneumonia. In addition this technique can use specimens which were not stored properly and became non suitable for microscopy.