1. Diagnosis of Pneumocystis pneumonia by real-time PCR in patients with various underlying diseases
- Author
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Shuan Yang, Pi-Yueh Chang, Shu-Li Yang, Mei-Chia Wang, Ying-Hao Wen, Yu-Shan Wu, and Jang-Jih Lu
- Subjects
Male ,0301 basic medicine ,Microbiology (medical) ,medicine.medical_specialty ,Opportunistic infection ,030106 microbiology ,Underlying diseases ,lcsh:QR1-502 ,HIV Infections ,Disease ,Pneumocystis carinii ,Pneumocystis pneumonia ,Polymerase Chain Reaction ,Sensitivity and Specificity ,Gastroenterology ,lcsh:Microbiology ,03 medical and health sciences ,0302 clinical medicine ,Pcr test ,Neoplasms ,Internal medicine ,medicine ,Humans ,Immunology and Allergy ,Pneumocystis jirovecii ,In patient ,030212 general & internal medicine ,DNA, Fungal ,Aged ,General Immunology and Microbiology ,biology ,business.industry ,Pneumonia, Pneumocystis ,Genes, rRNA ,General Medicine ,Middle Aged ,medicine.disease ,biology.organism_classification ,respiratory tract diseases ,Infectious Diseases ,Real-time polymerase chain reaction ,Sputum ,Female ,medicine.symptom ,Tomography, X-Ray Computed ,business - Abstract
Background Pneumocystis pneumonia (PCP) is a disease caused by the opportunistic infection of the fungus Pneumocystis jirovecii. Several PCR methods have been developed to aid in the diagnosis of PCP. In this study, we evaluated the performance of a real-time PCR in the diagnosis of PCP, in patients with various underlying diseases. Methods Ninety-seven BAL samples and 94 sputum samples from 191 patients were used in the study. Patients were classified as PCP (121 patients) or non-PCP (70 patients) based on their clinical and radiological presentations. Results Real time PCR amplified the P. jirovecii mitochondrial large-subunit rRNA gene with a detection limit of 68 copies of DNA per reaction. Non-PCP pathogens including 32 different fungi and bacteria were also evaluated. Overall, 71.9% of the samples from PCP patients and 14.5% of those from non-PCP patients were positive for the PCR test with a CT value of the real-time PCR below 45. The main underlying diseases of the patients were hematological or solid malignancies (47.1%) and HIV infection (8.9%). The CT values of the test were significantly lower in BAL samples from PCP patients than those from non-PCP patients (p = 0.024). No non-PCP patient had a CT value below 30, whereas samples from 24.8% of PCP patients with underlying diseases had a CT value below 30. Conclusion Since false positive PCR results were obtained, perhaps due to colonization, we suggest that the diagnosis of PCP should be based on a combination of clinical symptoms, underlying diseases, and PCR results.
- Published
- 2020