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Oreskovic A, Panpradist N, Marangu D, Ngwane MW, Magcaba ZP, Ngcobo S, Ngcobo Z, Horne DJ, Wilson DPK, Shapiro AE, Drain PK, Lutz BR. Diagnosing Pulmonary Tuberculosis by Using Sequence-Specific Purification of Urine Cell-Free DNA. J Clin Microbiol 2021; 59:e0007421. [PMID: 33789959 PMCID: PMC8373247 DOI: 10.1128/jcm.00074-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 03/19/2021] [Indexed: 01/17/2023] Open
Abstract
Transrenal urine cell-free DNA (cfDNA) is a promising tuberculosis (TB) biomarker, but is challenging to detect because of the short length (<100 bp) and low concentration of TB-specific fragments. We aimed to improve the diagnostic sensitivity of TB urine cfDNA by increasing recovery of short fragments during sample preparation. We developed a highly sensitive sequence-specific purification method that uses hybridization probes immobilized on magnetic beads to capture short TB cfDNA (50 bp) with 91.8% average efficiency. Combined with short-target PCR, the assay limit of detection was ≤5 copies of cfDNA in 10 ml urine. In a clinical cohort study in South Africa, our urine cfDNA assay had 83.7% sensitivity (95% CI: 71.0 to 91.5%) and 100% specificity (95% CI: 86.2 to 100%) for diagnosis of active pulmonary TB when using sputum Xpert MTB/RIF as the reference standard. The detected cfDNA concentration was 0.14 to 2,804 copies/ml (median 14.6 copies/ml) and was inversely correlated with CD4 count and days to culture positivity. Sensitivity was nonsignificantly higher in HIV-positive (88.2%) compared to HIV-negative patients (73.3%), and was not dependent on CD4 count. Sensitivity remained high in sputum smear-negative (76.0%) and urine lipoarabinomannan (LAM)-negative (76.5%) patients. With improved sample preparation, urine cfDNA is a viable biomarker for TB diagnosis. Our assay has the highest reported accuracy of any TB urine cfDNA test to date and has the potential to enable rapid non-sputum-based TB diagnosis across key underserved patient populations.
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Affiliation(s)
- Amy Oreskovic
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Nuttada Panpradist
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Diana Marangu
- Department of Paediatrics and Child Health, University of Nairobi, Nairobi, Kenya
| | - M. William Ngwane
- Umkhuseli Innovation and Research Management, Pietermaritzburg, South Africa
| | - Zanele P. Magcaba
- Umkhuseli Innovation and Research Management, Pietermaritzburg, South Africa
| | - Sindiswa Ngcobo
- Umkhuseli Innovation and Research Management, Pietermaritzburg, South Africa
| | - Zinhle Ngcobo
- Umkhuseli Innovation and Research Management, Pietermaritzburg, South Africa
| | - David J. Horne
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Douglas P. K. Wilson
- Umkhuseli Innovation and Research Management, Pietermaritzburg, South Africa
- Edendale Hospital, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Adrienne E. Shapiro
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Paul K. Drain
- Department of Medicine, University of Washington, Seattle, Washington, USA
- Department of Global Health, University of Washington, Seattle, Washington, USA
| | - Barry R. Lutz
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
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