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Tyagi S, Katara P. Metatranscriptomics: A Tool for Clinical Metagenomics. OMICS : A JOURNAL OF INTEGRATIVE BIOLOGY 2024; 28:394-407. [PMID: 39029911 DOI: 10.1089/omi.2024.0130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/21/2024]
Abstract
In the field of bioinformatics, amplicon sequencing of 16S rRNA genes has long been used to investigate community membership and taxonomic abundance in microbiome studies. As we can observe, shotgun metagenomics has become the dominant method in this field. This is largely owing to advancements in sequencing technology, which now allow for random sequencing of the entire genetic content of a microbiome. Furthermore, this method allows profiling both genes and the microbiome's membership. Although these methods have provided extensive insights into various microbiomes, they solely assess the existence of organisms or genes, without determining their active role within the microbiome. Microbiome scholarship now includes metatranscriptomics to decipher how a community of microorganisms responds to changing environmental conditions over a period of time. Metagenomic studies identify the microbes that make up a community but metatranscriptomics explores the diversity of active genes within that community, understanding their expression profile and observing how these genes respond to changes in environmental conditions. This expert review article offers a critical examination of the computational metatranscriptomics tools for studying the transcriptomes of microbial communities. First, we unpack the reasons behind the need for community transcriptomics. Second, we explore the prospects and challenges of metatranscriptomic workflows, starting with isolation and sequencing of the RNA community, then moving on to bioinformatics approaches for quantifying RNA features, and statistical techniques for detecting differential expression in a community. Finally, we discuss strengths and shortcomings in relation to other microbiome analysis approaches, pipelines, use cases and limitations, and contextualize metatranscriptomics as a tool for clinical metagenomics.
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Affiliation(s)
- Shivani Tyagi
- Computational Omics Lab, Centre of Bioinformatics, IIDS, University of Allahabad, Prayagraj, India
| | - Pramod Katara
- Computational Omics Lab, Centre of Bioinformatics, IIDS, University of Allahabad, Prayagraj, India
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Mesman AW, Calderon RI, Hauns L, Pollock NR, Mendoza M, Holmberg RC, Franke MF. Detection of Mycobacterium tuberculosis transrenal DNA in urine samples among adults in Peru. Tuberculosis (Edinb) 2024; 148:102549. [PMID: 39098064 DOI: 10.1016/j.tube.2024.102549] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 07/22/2024] [Accepted: 07/23/2024] [Indexed: 08/06/2024]
Abstract
Diagnosis of pulmonary tuberculosis (TB) relies on a sputum sample, which cannot be obtained from all symptomatic individuals. Mycobacterium tuberculosis (Mtb) transrenal DNA (trDNA) has been detected in urine, an easily obtainable, noninvasive, alternative sample type. However, reported sensitivities have been variable and likely depend on collection and assay procedures and aspects of trDNA biology. We analyzed three serial urine samples from each of 75 adults with culture-confirmed pulmonary TB disease in Lima, Peru for detection of trDNA using short-fragment real-time PCR. Additionally, we examined host, urine, and sampling factors associated with detection. Overall per-sample sensitivity was 38 % (95 % Confidence Interval [CI] 30-45 %). On an individual level (i.e., any of the three samples positive), sensitivity was 73 % (95 % CI: 62-83 %). Sensitivity was highest among samples from patients with smear-positive TB, 92 % (95 % CI: 62-100 %). Specificity from a single sample from each of 10 healthy controls was 100 % (95 % CI: 69-100 %). Adjusting our assay positivity threshold increased individual-level sensitivity to 88 % (95 % CI: 78-94 %) overall without affecting the specificity. We did not find associations between Mtb trDNA detection and individual characteristics or urine sample characteristics. Overall, our results support the potential of trDNA detection for TB diagnosis.
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Affiliation(s)
- Annelies W Mesman
- Department of Global Health and Social Medicine, Harvard Medical School, 641 Huntington Ave, Boston, MA, 02115, USA.
| | - Roger I Calderon
- Socios En Salud Sucursal Perú, Av. Javier Prado Este 492, San Isidro, Lima, 15001, Peru.
| | - Laura Hauns
- Akonni Biosystems, 400 Sagner Ave, Frederick, MD, 21701, USA.
| | - Nira R Pollock
- Department of Laboratory Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA, 02115, USA.
| | - Milagros Mendoza
- Socios En Salud Sucursal Perú, Av. Javier Prado Este 492, San Isidro, Lima, 15001, Peru.
| | | | - Molly F Franke
- Department of Global Health and Social Medicine, Harvard Medical School, 641 Huntington Ave, Boston, MA, 02115, USA.
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Rodrigues C, Singhal T. What is New in the Diagnosis of Childhood Tuberculosis? Indian J Pediatr 2024; 91:717-723. [PMID: 38163830 DOI: 10.1007/s12098-023-04992-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 12/08/2023] [Indexed: 01/03/2024]
Abstract
The fact that almost half of the 1 million cases of childhood tuberculosis (TB) globally remain undiagnosed jeopardizes the TB elimination goal. Fortunately, there are new advances in this field which have the potential to bridge this diagnostic gap. Advances in imaging include computer assisted interpretation of chest X-rays (CXRs), point of care ultrasound (POCUS) and faster and superior computed tomography/ magnetic resonance imaging (CT/ MRI) protocols. The urine lipoarabinomannan test has proved to be a good point of care test for diagnosing TB in Human immunodeficiency virus (HIV) infected children. Stool and nasopharyngeal aspirates are emerging as acceptable alternatives for gastric lavage and induced sputum for diagnosing intrathoracic tuberculosis. Xpert MTB/RIF Ultra has improved sensitivity compared to Xpert MTB/RIF for diagnosing both pulmonary/ extrapulmonary TB. Xpert XDR is another commercially available accurate point of care test for detecting resistance to drugs other than rifampicin in smear positive samples. Other molecular methods including new line probe assays, pyrosequencing, whole genome sequencing, and targeted next generation sequencing are extremely promising but not available commercially at present. The C-Tb skin test is an acceptable alternative to the tuberculin skin test and interferon gamma release assays for diagnosis of latent infection. There is an urgent need to incorporate some of these advances in the existing diagnostic algorithms of childhood TB.
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Affiliation(s)
- Camilla Rodrigues
- Department of Microbiology & Infection Prevention Control, Hinduja Hospital, Mahim, Mumbai, India
| | - Tanu Singhal
- Department of Pediatrics and Infectious Disease, Kokilaben Dhirubhai Ambani Hospital and Medical Research Institute, Mumbai, India.
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Li G, Cannon K, Sisniega C, Fergie J. Cell-free DNA blood test for the diagnosis of pediatric tuberculous meningitis. J Clin Tuberc Other Mycobact Dis 2024; 35:100421. [PMID: 38420617 PMCID: PMC10899014 DOI: 10.1016/j.jctube.2024.100421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
Pediatric tuberculous meningitis (TBM) is a severe form of tuberculosis that may present in children. The current diagnostic methods may have a limited impact on initial clinical decision-making. We present three children with tuberculous meningitis who had Mycobacterium tuberculosis complex cell-free DNA (cfDNA) detected in their blood within three days of sampling. Our cases described here illustrate for the first time the potential role of cfDNA blood tests in the rapid diagnosis of TBM.
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Affiliation(s)
- Guyu Li
- Division of Pediatric Infectious Diseases, Department of Pediatric and Adolescent Medicine, Mayo Clinic, Rochester, MN 55905, United States
| | - Kendall Cannon
- Driscoll Children's Hospital/ Texas A&M College of Medicine, Corpus Christi, TX 78411, United States
| | - Carlos Sisniega
- Division of Pediatric Cardiology, UCLA Mattel Children's Hospital, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, United States
| | - Jaime Fergie
- Department of Infectious Disease, Driscoll Children's Hospital/ Texas A&M College of Medicine, Corpus Christi, TX 78411, United States
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Bell DT. Deciphering the potential of plasma cell-free metagenomic next-generation sequencing using the Karius test. Curr Opin Infect Dis 2023; 36:420-425. [PMID: 37493238 DOI: 10.1097/qco.0000000000000942] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
PURPOSE OF REVIEW Plasma cell-free metagenomic next-generation sequencing (cf-mNGS) is increasingly employed for the diagnosis of infection, but a consensus for optimal use has not been established. This minireview focuses on the commercially available Karius Test and is aimed at local leaders seeking to understand the complexities of cf-mNGS to make informed test utilization policies and better interpret results. RECENT FINDINGS Recent retrospective studies have reported how the Karius Test was applied at their institutions and identified areas of potential patient benefit. In addition, substantive studies have reported how this test performs in specific indications, particularly invasive fungal disease, endovascular infection and lower respiratory infection. SUMMARY Successfully integrating plasma cf-mNGS requires careful assessment of performance in the specific applications and patient populations in which it is used. Individual institutions must independently evaluate implementation strategies and determine where diagnostic yields outweigh the potential pitfalls.
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Affiliation(s)
- Drew T Bell
- Department of Laboratories, Seattle Children's Hospital, Seattle, Washington, USA
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Shaikh A, Rodrigues C. What's New in the Molecular Diagnosis of Childhood Tuberculosis? Pediatr Infect Dis J 2023; 42:e377-e379. [PMID: 37463349 DOI: 10.1097/inf.0000000000004044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 07/20/2023]
Affiliation(s)
- Ambreen Shaikh
- From the Department of Laboratory Medicine, Section Tuberculosis, Foundation Medical Research, Worli, Mumbai, India
| | - Camilla Rodrigues
- Department of Laboratory Medicine, Section Microbiology, Hinduja Hospital, Mahim, Mumbai, India
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Park SY, Chang EJ, Ledeboer N, Messacar K, Lindner MS, Venkatasubrahmanyam S, Wilber JC, Vaughn ML, Bercovici S, Perkins BA, Nolte FS. Plasma Microbial Cell-Free DNA Sequencing from over 15,000 Patients Identified a Broad Spectrum of Pathogens. J Clin Microbiol 2023; 61:e0185522. [PMID: 37439686 PMCID: PMC10446866 DOI: 10.1128/jcm.01855-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 06/23/2023] [Indexed: 07/14/2023] Open
Abstract
Microbial cell-free DNA (mcfDNA) sequencing is an emerging infectious disease diagnostic tool which enables unbiased pathogen detection and quantification from plasma. The Karius Test, a commercial mcfDNA sequencing assay developed by and available since 2017 from Karius, Inc. (Redwood City, CA), detects and quantifies mcfDNA as molecules/μL in plasma. The commercial sample data and results for all tests conducted from April 2018 through mid-September 2021 were evaluated for laboratory quality metrics, reported pathogens, and data from test requisition forms. A total of 18,690 reports were generated from 15,165 patients in a hospital setting among 39 states and the District of Columbia. The median time from sample receipt to reported result was 26 h (interquartile range [IQR] 25 to 28), and 96% of samples had valid test results. Almost two-thirds (65%) of patients were adults, and 29% at the time of diagnostic testing had ICD-10 codes representing a diverse array of clinical scenarios. There were 10,752 (58%) reports that yielded at least one taxon for a total of 22,792 detections spanning 701 unique microbial taxa. The 50 most common taxa detected included 36 bacteria, 9 viruses, and 5 fungi. Opportunistic fungi (374 Aspergillus spp., 258 Pneumocystis jirovecii, 196 Mucorales, and 33 dematiaceous fungi) comprised 861 (4%) of all detections. Additional diagnostically challenging pathogens (247 zoonotic and vector-borne pathogens, 144 Mycobacterium spp., 80 Legionella spp., 78 systemic dimorphic fungi, 69 Nocardia spp., and 57 protozoan parasites) comprised 675 (3%) of all detections. This is the largest reported cohort of patients tested using plasma mcfDNA sequencing and represents the first report of a clinical grade metagenomic test performed at scale. Data reveal new insights into the breadth and complexity of potential pathogens identified.
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Affiliation(s)
| | | | | | - Kevin Messacar
- University of Colorado, Children’s Hospital Colorado, Aurora, Colorado, USA
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Mesman AW, Calderon RI, Hauns L, Pollock NR, Mendoza M, Holmberg RC, Franke MF. Detection of Mycobacterium tuberculosis transrenal DNA in urine samples among adult patients in Peru. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.07.26.23293199. [PMID: 37546779 PMCID: PMC10402216 DOI: 10.1101/2023.07.26.23293199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/08/2023]
Abstract
Diagnosis of tuberculosis (TB) relies on a sputum sample, which cannot be obtained from all symptomatic patients. Mycobacterium tuberculosis (Mtb) transrenal DNA (trDNA) has been detected in urine, an easily obtainable, noninvasive, alternative sample type. However, reported sensitivities have been variable and likely depend on collection/assay procedures and aspects of trDNA biology. We analyzed three serial urine samples from each of 75 adults with culture-confirmed pulmonary TB disease in Lima, Peru for detection of trDNA using short-fragment real-time PCR. Additionally, we examined host, urine, and sampling factors associated with detection. Overall sample sensitivity was 38% (95% Confidence Interval [CI] 30-45%). On a patient level (i.e., any of three samples positive), sensitivity was 73% (95% CI: 62-83%). Sensitivity was highest among samples from patients with smear-positive TB, 92% (95% CI: 62-100%). Specificity from a single sample from each of 10 healthy controls was 100% (95% CI: 69-100%). Adjusting our assay positivity threshold increased patient-level sensitivity to 88% (95% CI: 78-94%) overall without affecting the specificity. We did not find associations between Mtb trDNA detection and either patient characteristics or urine sample characteristics. Overall, our results support the potential of trDNA detection for TB diagnosis.
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Affiliation(s)
- Annelies W Mesman
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA
| | | | | | - Nira R Pollock
- Department of Laboratory Medicine, Boston Children’s Hospital, Boston, MA
| | | | | | - Molly F Franke
- Department of Global Health and Social Medicine, Harvard Medical School, Boston, MA
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Batool M, Galloway-Peña J. Clinical metagenomics-challenges and future prospects. Front Microbiol 2023; 14:1186424. [PMID: 37448579 PMCID: PMC10337830 DOI: 10.3389/fmicb.2023.1186424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Accepted: 06/12/2023] [Indexed: 07/15/2023] Open
Abstract
Infections lacking precise diagnosis are often caused by a rare or uncharacterized pathogen, a combination of pathogens, or a known pathogen carrying undocumented or newly acquired genes. Despite medical advances in infectious disease diagnostics, many patients still experience mortality or long-term consequences due to undiagnosed or misdiagnosed infections. Thus, there is a need for an exhaustive and universal diagnostic strategy to reduce the fraction of undocumented infections. Compared to conventional diagnostics, metagenomic next-generation sequencing (mNGS) is a promising, culture-independent sequencing technology that is sensitive to detecting rare, novel, and unexpected pathogens with no preconception. Despite the fact that several studies and case reports have identified the effectiveness of mNGS in improving clinical diagnosis, there are obvious shortcomings in terms of sensitivity, specificity, costs, standardization of bioinformatic pipelines, and interpretation of findings that limit the integration of mNGS into clinical practice. Therefore, physicians must understand the potential benefits and drawbacks of mNGS when applying it to clinical practice. In this review, we will examine the current accomplishments, efficacy, and restrictions of mNGS in relation to conventional diagnostic methods. Furthermore, we will suggest potential approaches to enhance mNGS to its maximum capacity as a clinical diagnostic tool for identifying severe infections.
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Affiliation(s)
| | - Jessica Galloway-Peña
- Department of Veterinary Pathobiology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
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