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Saavedra B, Mambuque E, Gomes N, Nguenha D, Mabunda R, Faife L, Langa R, Munguambe S, Manjate F, Cossa A, Scott L, García-Basteiro AL. Diagnostic performance of the Abbott RealTime MTB assay for tuberculosis diagnosis in people living with HIV. Sci Rep 2021; 11:19271. [PMID: 34588508 PMCID: PMC8481474 DOI: 10.1038/s41598-021-96922-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/02/2021] [Indexed: 11/09/2022] Open
Abstract
Strengthening tuberculosis diagnosis is an international priority and the advocacy for multi-disease testing devices raises the possibility of improving laboratory efficiency. However, the advantages of centralized platforms might not translate into real improvements under operational conditions. This study aimed to evaluate the field use of the Abbott RealTime MTB (RT-MTB) and Xpert MTB/RIF assays, in a large cohort of HIV-positive and TB presumptive cases in Southern Mozambique. Over a 6-month period, 255 HIV-positive TB presumptive cases were consecutively recruited in the high TB/HIV burden district of Manhiça. The diagnostic performance of both assays was evaluated against two different reference standards: a microbiological gold standard (MGS) and a composite reference standard (CRS). Results from the primary analysis (MGS) showed improved sensitivity (Se) and reduced specificity (Sp) for the Abbott RT-MTB assay compared to the Xpert MTB/RIF (RT-MTB Se: 0.92 (95% CI: 0.75;0.99) vs Xpert Se: 0.73 (95% CI: 0.52;0.88) p value = 0.06; RT-MTB Sp: 0.80 (0.72;0.86) vs Xpert Sp: 0.96 (0.92;0.99) p value < 0.001). The lower specificity may be due to cross-reactivity with non-tuberculous mycobacteria (NTMs), the detection of non-viable MTBC, or the identification of true TB cases missed by the gold standard.
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Affiliation(s)
- Belén Saavedra
- PhD Program in Medicine and Translational Research, Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique.
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
| | - Edson Mambuque
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Neide Gomes
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Dinis Nguenha
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Rita Mabunda
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Luis Faife
- Manhiça Health Research Hospital, Ministry of Health, National Tuberculosis Control Program, Maputo, Mozambique
| | - Ruben Langa
- Manhiça Health Research Hospital, Ministry of Health, National Tuberculosis Control Program, Maputo, Mozambique
| | - Shilzia Munguambe
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Filomena Manjate
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Anelsio Cossa
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, School of Pathology, and iLEAD, Faculty of Health Sciences, Wits Health Consortium, University of the Witwatersrand, Johannesburg, South Africa
| | - Alberto L García-Basteiro
- Centro de Investigação Em Saude de Manhiça (CISM), Maputo, Mozambique
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
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Retrospective Diagnostic Accuracy Study of Abbott RealTi me MTB against Xpert MTB/RIF Ultra and Xpert MTB/RIF for the Diagnosis of Pulmonary Tuberculosis and Susceptibility to Rifampin and Isoniazid Treatment. Microbiol Spectr 2021; 9:e0013221. [PMID: 34406811 PMCID: PMC8552641 DOI: 10.1128/spectrum.00132-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
High-throughput centralized testing for tuberculosis (TB) and drug resistance is important, but comparative data are limited. In this retrospective cross-sectional study, participants were recruited from Johannesburg, South Africa, and Tbilisi, Georgia. The index tests, Abbott RealTime MTB (RT-MTB) and RealTime MTB RIF/INH (RT-MTB RIF/INH), were performed on specimens stored frozen for an extended period of time (beyond manufacturer-validated specifications) and compared to paired Xpert MTB/RIF Ultra (Xpert Ultra) and Xpert MTB/RIF (Xpert) results obtained with fresh specimens. The detection reference standard was the Mycobacterium tuberculosis complex culture, and for resistance detection, it was phenotypic drug susceptibility testing. The median age of 474 participants was 39 (interquartile range [IQR], 31 to 51) years. On decontaminated sputum, Xpert Ultra had a sensitivity of 91%, compared to 77% for RT-MTB, with a difference of +14% (95% confidence interval [CI], +9.2 to +21%; 18/127). On raw sputum, Xpert Ultra exhibited a sensitivity of 89% and Xpert one of 88%, compared to 80% for RT-MTB, exhibiting differences of +10% (95% CI, +3.3 to +18%; 9/93) and +8.6% (95% CI, +2.4 to +17%; 8/93), respectively. Specificity was ≥98% for all tests. All three tests showed high sensitivity and specificity for detection of rifampin resistance. Abbott assays may have lower sensitivity than Xpert and Xpert Ultra for TB detection but similar performance for detection of resistance. The differences in TB detection may be attributable to differences in testing of frozen (Abbott) versus fresh (Xpert) samples. Studies in compliance with manufacturer’s instructions are required to compare performance. IMPORTANCE In 2019, 10 million people fell ill with tuberculosis (TB), of whom 1.4 million died. There are few comparative studies of diagnostic assays, particularly those aiming to be used in high-throughput laboratories. One such assay is the Abbott RealTime MTB (RT-MTB) and RealTime MTB RIF/INH (RT-MTB RIF/INH), which uses the m2000 platform already in use in many settings for HIV load testing and allows the diagnosis of TB and resistance to two first-line drugs, rifampin and isoniazid. Our study compared the RT-MTB and RT-MTB RIF/INH to the WHO-recommended Xpert MTB/RIF Ultra and Xpert MTB/RIF. The study is the largest comparative study to date and was performed independent of the manufacturer. The study results suggest that the Abbott RealTime MTB may have a lower sensitivity, but the study may have placed the Abbott test at a disadvantage by using frozen samples and comparing the results to those for fresh samples for the Xpert.
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Performance of the Abbott RealTime MTB and RIF/INH resistance assays for the detection of Mycobacterium Tuberculosis and resistance markers in sputum specimens. PLoS One 2021; 16:e0251602. [PMID: 33979395 PMCID: PMC8115802 DOI: 10.1371/journal.pone.0251602] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 04/28/2021] [Indexed: 11/19/2022] Open
Abstract
Background The Abbott RealTime MTB is an assay for the detection of Mycobacterium tuberculosis (MTB) complex DNA from respiratory specimens in combination with the Abbott RealTime RIF/INH assay for the detection of genetic resistance markers for isoniazid (INH) and rifampicin (RIF) from MTB positive isolates. Hence, this study aimed to evaluate the performance of the Abbott RealTime MTB and RIF/INH assays. Methods A cross-sectional study was conducted on 289 study subjects presumptive to have pulmonary tuberculosis at Nigist Eleni Mohammed Memorial Hospital, South Ethiopia from April 2017 to June 2018. Two morning expectorated sputum specimens were collected from each study participant. One sample was tested directly by Xpert MTB/RIF assay at Nigist Eleni Mohammed Memorial Hospital and the other sample was used for smear microscopy, TB culture, Abbott RealTime MTB, and Abbott RealTime INH/RIF assays at International Clinical Laboratories, Addis Ababa, Ethiopia. The diagnostic performance of the Abbott RealTime MTB and INH/RIF assays were calculated against MGIT liquid culture and phenotypic drug susceptibility testing (DST) as the gold standard. Results For the detection of MTB the Abbott RealTime MTB assay exhibited sensitivity 92.4% (95% CI 83.6–96.9), specificity 95.4% (95% CI 91.1–97.7), PPV 89.0% (95% CI 79.7–94.5) and NPV 96.9% (95% CI 93.0–98.7). For the detection of RIF resistance MTB, Abbott RealTime MTB RIF/INH concurred with phenotypic DST and Xpert MTB/RIF, while for the detection of INH resistance MTB, the sensitivity, specificity, PPV and NPV of the Abbott MTB RIF/INH assay was 84.2% (95% CI 60.4–96.6), 100% (95% CI 89.7–100), 100% and 91.9% (95% CI 80.0–96.9), respectively. Conclusions The Abbott RTMTB and RIF/INH assays revealed high sensitivity and specificity in MTB diagnosis and provided reliable INH and RIF resistance profiles. This assay has a similar diagnostic performance to the Xpert MTB/RIF assay with the advantages of high-throughput.
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Kohli M, MacLean E, Pai M, Schumacher SG, Denkinger CM. Diagnostic accuracy of centralised assays for TB detection and detection of resistance to rifampicin and isoniazid: a systematic review and meta-analysis. Eur Respir J 2021; 57:13993003.00747-2020. [PMID: 32855226 DOI: 10.1183/13993003.00747-2020] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 07/30/2020] [Indexed: 11/05/2022]
Abstract
Various diagnostic companies have developed high throughput molecular assays for tuberculosis (TB) and resistance detection for rifampicin and isoniazid. We performed a systematic review and meta-analyses to assess the diagnostic accuracy of five of these tests for pulmonary specimens. The tests included were Abbott RealTime MTB, Abbott RealTime RIF/INH, FluoroType MTB, FluoroType MTDBR and BD Max MDR-TB assay.A comprehensive search of six databases for relevant citations was performed. Cross-sectional, case-control, cohort studies, and randomised controlled trials of any of the index tests were included. Respiratory specimens (such as sputum, bronchoalveolar lavage, tracheal aspirate, etc) or their culture isolates.A total of 21 included studies contributed 26 datasets. We could only meta-analyse data for three of the five assays identified, as data were limited for the remaining two. For TB detection, the included assays had a sensitivity of 91% or more and the specificity ranged from 97% to 100%. For rifampicin resistance detection, all the included assays had a sensitivity of more than 92%, with a specificity of 99-100%. Sensitivity for isoniazid resistance detection varied from 70 to 91%, with higher specificity of 99-100% across all index tests. Studies that included head-to-head comparisons of these assays with Xpert MTB/RIF for detection of TB and rifampicin resistance suggested comparable diagnostic accuracy.In people with symptoms of pulmonary TB, the centralised molecular assays demonstrate comparable diagnostic accuracy for detection of TB, rifampicin and isoniazid resistance to Xpert MTB/RIF assay, a WHO recommended molecular test.
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Affiliation(s)
- Mikashmi Kohli
- Dept of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.,McGill International TB Centre, McGill University, Montreal, QC, Canada
| | - Emily MacLean
- Dept of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.,McGill International TB Centre, McGill University, Montreal, QC, Canada
| | - Madhukar Pai
- Dept of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada.,McGill International TB Centre, McGill University, Montreal, QC, Canada
| | - Samuel G Schumacher
- Foundation for Innovative New Diagnostics, Geneva, Switzerland.,S.G. Schumacher and C.M. Denkinger are joint senior authors
| | - Claudia M Denkinger
- Foundation for Innovative New Diagnostics, Geneva, Switzerland.,Centre for Infectious Diseases, University Heidelberg, Heidelberg, Germany.,S.G. Schumacher and C.M. Denkinger are joint senior authors
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Zhou W, Sun J, Li X. Low-Cost Quantitative Photothermal Genetic Detection of Pathogens on a Paper Hybrid Device Using a Thermometer. Anal Chem 2020; 92:14830-14837. [PMID: 33059447 DOI: 10.1021/acs.analchem.0c03700] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Tuberculosis (TB), one of the deadliest infectious diseases, is caused by Mycobacterium tuberculosis (MTB) and remains a public health problem nowadays. Conventional MTB DNA detection methods require sophisticated infrastructure and well-trained personnel, which leads to increasing complexity and high cost for diagnostics and limits their wide accessibility in low-resource settings. To address these issues, we have developed a low-cost photothermal biosensing method for the quantitative genetic detection of pathogens such as MTB DNA on a paper hybrid device using a thermometer. First, DNA capture probes were simply immobilized on paper through a one-step surface modification process. After DNA sandwich hybridization, oligonucleotide-functionalized gold nanoparticles (AuNPs) were introduced on paper and then catalyzed the oxidation reaction of 3,3',5,5'-tetramethylbenzidine (TMB). The produced oxidized TMB, acting as a strong photothermal agent, was used for the photothermal biosensing of MTB DNA under 808 nm laser irradiation. Under optimal conditions, the on-chip quantitative detection of the target DNA was readily achieved using an inexpensive thermometer as a signal recorder. This method does not require any expensive analytical instrumentation but can achieve higher sensitivity and there are no color interference issues, compared to conventional colorimetric methods. The method was further validated by detecting genomic DNA with high specificity. To the best of our knowledge, this is the first photothermal biosensing strategy for quantitative nucleic acid analysis on microfluidics using a thermometer, which brings fresh inspirations on the development of simple, low-cost, and miniaturized photothermal diagnostic platforms for quantitative detection of a variety of diseases at the point of care.
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Affiliation(s)
- Wan Zhou
- Department of Chemistry and Biochemistry, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - Jianjun Sun
- Department of Biological Sciences, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
| | - XiuJun Li
- Department of Chemistry and Biochemistry, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States.,Biomedical Engineering, Border Biomedical Research Center, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States.,Environmental Science and Engineering, University of Texas at El Paso, 500 West University Avenue, El Paso, Texas 79968, United States
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David A, Singh L, Da Silva P, Scott L, Stevens W. The Performance of the Abbott Real Time MTB RIF/INH Compared to the MTBDR plus V2 for the Identification of MDR-TB Among Isolates. Infect Drug Resist 2020; 13:3301-3308. [PMID: 33061477 PMCID: PMC7532077 DOI: 10.2147/idr.s247524] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 08/08/2020] [Indexed: 11/23/2022] Open
Abstract
Background The GenoType MTBDRplus V2 line-probe assay (LPA) is routinely used in clinical patient management to characterise the susceptibility of Mycobacterium tuberculosis complex to rifampicin (Rif) and isoniazid (INH) directly from sputum and cultured isolates. The laboratory workflow requires skill and three separate areas to minimize contamination and banding pattern interpretation requires experienced laboratory personnel. We explored the use of the RT MTB RIF/INH assay performed on the Abbott m2000 platform as an alternative laboratory platform. Methods Isolates (n=93) consisting of fully susceptible, Rif- or INH-mono-resistant and multi-drug resistant (MDR) strains were tested on both MTBDRplus v2 and RT MTB RIF/INH assays. Both assays target the rpoB, katG and inhA genes for resistance-detection mutations. Concordance was assessed using percent agreement and the kappa statistic. Those specimens with discordant results were further assessed using Sanger sequencing. Results A total of 89% (83/93) of cultured isolates generated successful results on the RT MTB/RIF-INH assay and MTBDRplus assays. Of the 10 discordant results, where sequencing was used as the reference method, the RT MTB RIF/INH assays misclassified six resistance isolates, while the LPA misclassified seven. Discussion Overall, the RT MTB RIF/INH demonstrated good agreement with the LPA, and a better correlation with sequencing on discrepant isolates specifically with mutations occurring in codon 511 of the rpoB gene. The RT MTB RIF/INH therefore can be used to complement existing laboratory algorithms determining Rif and INH resistance profiles, with less emphasis on manual laboratory processing.
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Affiliation(s)
- Anura David
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Lyndel Singh
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Pedro Da Silva
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa.,National Priority Program, National Health Laboratory Services, Johannesburg, South Africa
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, University of the Witwatersrand, Johannesburg, South Africa.,National Priority Program, National Health Laboratory Services, Johannesburg, South Africa
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Abstract
Molecular tests for tuberculosis (TB) have the potential to help reach the three million people with TB who are undiagnosed or not reported each year and to improve the quality of care TB patients receive by providing accurate, quick results, including rapid drug-susceptibility testing. The World Health Organization (WHO) has recommended the use of molecular nucleic acid amplification tests (NAATs) tests for TB detection instead of smear microscopy, as they are able to detect TB more accurately, particularly in patients with paucibacillary disease and in people living with HIV. Importantly, some of these WHO-endorsed tests can detect mycobacterial gene mutations associated with anti-TB drug resistance, allowing clinicians to tailor effective TB treatment. Currently, a wide array of molecular tests for TB detection is being developed and evaluated, and while some tests are intended for reference laboratory use, others are being aimed at the point-of-care and peripheral health care settings. Notably, there is an emergence of molecular tests designed, manufactured, and rolled out in countries with high TB burden, of which some are explicitly aimed for near-patient placement. These developments should increase access to molecular TB testing for larger patient populations. With respect to drug susceptibility testing, NAATs and next-generation sequencing can provide results substantially faster than traditional phenotypic culture. Here, we review recent advances and developments in molecular tests for detecting TB as well as anti-TB drug resistance.
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Scott L, David A, Govender L, Furrer J, Rakgokong M, Waja Z, Martinson N, Eisenberg G, Marlowe E, Stevens W. Performance of the Roche cobas MTB Assay for the Molecular Diagnosis of Pulmonary Tuberculosis in a High HIV Burden Setting. J Mol Diagn 2020; 22:1225-1237. [PMID: 32745613 DOI: 10.1016/j.jmoldx.2020.06.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 05/25/2020] [Accepted: 06/26/2020] [Indexed: 12/21/2022] Open
Abstract
Increased access to and improved sensitivities of methods for diagnosing Mycobacterium tuberculosis infection and detecting rifampicin and isoniazid resistance are needed. Herein, the performance of the new cobas MTB assay for use on cobas 6800/8800 Systems (Roche) was assessed and compared with two other commercial assays: RealTime MTB (Abbott), and Xpert MTB/RIF (Cepheid). Molecular PCR-based assays were conducted on sputum specimens from individuals with presumptive and confirmed tuberculosis (n = 294) from two clinical facilities in South Africa between December 2016 and October 2017. Liquid mycobacterial culture was the reference. Test sensitivities were 94.7% (95% CI, 88%-98%), 92.6% (95% CI, 85%-97%), and 91.6% (95% CI, 84%-96%) for cobas MTB, RealTime MTB, and Xpert MTB/RIF assays, respectively. cobas MTB sensitivity was unaffected by HIV coinfection (95.7%; 95% CI, 88%-99%; n = 176) and sediment testing (94.7%; 95% CI, 88%-98%). Sensitivities were 81.8% (95% CI, 60%-95%), 72.7% (95% CI, 50%-89%), and 72.7% (95% CI, 50%-89%) among smear-negative, culture-positive individuals (n = 221) for cobas MTB, RealTime MTB, and Xpert MTB/RIF assays, respectively. cobas MTB specificity was 95.7% (95% CI, 89%-99%) and 99% (95% CI, 94%-100%) among HIV coinfected and uninfected individuals, respectively. The cobas 6800/8800 system is already implemented in South Africa for high-throughput HIV viral load testing, making it suitable for integrated HIV/tuberculosis diagnostics.
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Affiliation(s)
- Lesley Scott
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa.
| | - Anura David
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Lyndel Govender
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Jan Furrer
- Division of Clinical Operations, Roche Molecular Diagnostics, Rotkreuz, Switzerland
| | - Modiehi Rakgokong
- Perinatal HIV Research Unit, Soweto Matlosana Collaborating Centre for HIV/AIDS and TB, University of the Witwatersrand, Johannesburg, South Africa
| | - Ziyaad Waja
- Perinatal HIV Research Unit, Soweto Matlosana Collaborating Centre for HIV/AIDS and TB, University of the Witwatersrand, Johannesburg, South Africa
| | - Neil Martinson
- Perinatal HIV Research Unit, Soweto Matlosana Collaborating Centre for HIV/AIDS and TB, University of the Witwatersrand, Johannesburg, South Africa; Center for Tuberculosis Research, Johns Hopkins University, Baltimore, Maryland
| | - Gabriel Eisenberg
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa
| | - Elizabeth Marlowe
- Medical and Scientific Affairs, Roche Molecular Diagnostics, Pleasanton, California
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Science, University of the Witwatersrand, Johannesburg, South Africa; National Priority Programme of the National Health Laboratory Service, Johannesburg, South Africa
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Hofmann-Thiel S, Plesnik S, Mihalic M, Heiß-Neumann M, Avsar K, Beutler M, Hoffmann H. Clinical Evaluation of BD MAX MDR-TB Assay for Direct Detection of Mycobacterium tuberculosis Complex and Resistance Markers. J Mol Diagn 2020; 22:1280-1286. [PMID: 32688054 DOI: 10.1016/j.jmoldx.2020.06.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Revised: 06/10/2020] [Accepted: 06/26/2020] [Indexed: 11/29/2022] Open
Abstract
BD MAX MDR-TB assay is a new molecular platform for the detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens and simultaneous detection of resistance toward isoniazid and rifampicin. This study assessed the assay's diagnostic accuracy by using pre-characterized MTBC culture-negative (n = 257), smear-negative/MTBC culture-positive (n = 93), and smear-positive/MTBC culture-positive (n = 153) respiratory specimens. Compared with culture, the overall sensitivity and specificity of BD MAX MDR-TB were 86.6% and 100%, respectively; sensitivities for smear-positive and smear-negative samples were 100% and 64.5%. Sensitivity and specificity for isoniazid and rifampicin resistance were 58.3% (biased low due to sample collection strategy in low prevalence setting), 99.3%, 100%, and 98.2%, compared with phenotypic drug resistance testing and 100%, 99.4%, 100%, and 99.4%, compared with GenoType MTBDRplus. In conclusion, BD MAX MDR-TB is an accurate assay for the diagnostic detection of MTBC in respiratory samples and its resistance toward the most important anti-TB drugs isoniazid and rifampicin. Due to its medium to high throughput, good validity, and ease of use, the assay will be of great benefit for medium-sized to large TB diagnostic centers.
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Affiliation(s)
- Sabine Hofmann-Thiel
- SYNLAB Gauting, SYNLAB MVZ Human Genetics, Munich, Germany; World Health Organization (WHO)-Supranational Reference Laboratory of Tuberculosis, Institute of Microbiology and Laboratory Diagnostics (IML) red GmbH, Munich-Gauting, Germany.
| | - Sara Plesnik
- World Health Organization (WHO)-Supranational Reference Laboratory of Tuberculosis, Institute of Microbiology and Laboratory Diagnostics (IML) red GmbH, Munich-Gauting, Germany
| | - Marina Mihalic
- World Health Organization (WHO)-Supranational Reference Laboratory of Tuberculosis, Institute of Microbiology and Laboratory Diagnostics (IML) red GmbH, Munich-Gauting, Germany
| | - Marion Heiß-Neumann
- Infectious Disease Department, Asklepios Pulmonary Hospital, Munich-Gauting, Germany
| | - Korkut Avsar
- Infectious Disease Department, Asklepios Pulmonary Hospital, Munich-Gauting, Germany
| | - Markus Beutler
- World Health Organization (WHO)-Supranational Reference Laboratory of Tuberculosis, Institute of Microbiology and Laboratory Diagnostics (IML) red GmbH, Munich-Gauting, Germany
| | - Harald Hoffmann
- SYNLAB Gauting, SYNLAB MVZ Human Genetics, Munich, Germany; World Health Organization (WHO)-Supranational Reference Laboratory of Tuberculosis, Institute of Microbiology and Laboratory Diagnostics (IML) red GmbH, Munich-Gauting, Germany
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Borrás R, Martínez V, Vinuesa V, Torres I, Orta N, Clari MÁ, Prat J, Navarro D. Field performance of the Abbott RealTime MTB assay for the diagnosis of extrapulmonary tuberculosis in a low-prevalence setting. Enferm Infecc Microbiol Clin 2019; 38:206-211. [PMID: 31668859 DOI: 10.1016/j.eimc.2019.08.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/05/2019] [Accepted: 08/22/2019] [Indexed: 11/16/2022]
Abstract
INTRODUCTION The sensitivities of conventional mycobacterial culture in solid or liquid media and acid-fast bacilli (AFB) smear microscopy for Mycobacterium tuberculosis complex (MTBC) detection in extrapulmonary specimens are suboptimal. We evaluated the field performance of the Abbott RealTime MTB assay for the diagnosis of extrapulmonary tuberculosis in a low-prevalence setting. METHODS The total number of extrapulmonary specimens with mycobacterial culture and PCR results was 566: sterile fluids (n=278), non-sterile fluids (n=147), lymph node material (n=69) tissue biopsies (n=63), and abscess aspirates (n=9). A composite standard consisting of mycobacterial culture results, clinical treatment response to anti-TB drugs, when administered, and histopathology, radiological and laboratory findings were used as a reference for sensitivity and specificity calculations. RESULTS Mycobacterial cultures and PCR were positive in 17 and 28 specimens, respectively. The overall agreement between culture and PCR was moderate (Cohen's kappa coefficient: 0.549; P=0.0001). Taking as a reference our composite standard, the sensitivity of the Abbott PCR assay was 77.7%, the specificity 99.5%, the PPV 95.4%, and the NPV 98.8%. In turn, the sensitivity of the mycobacterial culture was 62.9%, the specificity and PPV 100%, and the NPV 97.9%. CONCLUSION The good field performance of the Abbott RealTime MTB assay makes it valuable for the diagnosis of extrapulmonary tuberculosis in a low-prevalence setting. The use of molecular methods along with culture improves the diagnosis of extrapulmonary tuberculosis.
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Affiliation(s)
- Rafael Borrás
- Microbiology Service, Hospital Clínico Universitario, Instituto de Investigación INCLIVA, Valencia, Spain; Department of Microbiology, School of Medicine, University of Valencia, Valencia, Spain
| | - Víctor Martínez
- Microbiology Service, Hospital Clínico Universitario, Instituto de Investigación INCLIVA, Valencia, Spain
| | - Víctor Vinuesa
- Microbiology Service, Hospital Clínico Universitario, Instituto de Investigación INCLIVA, Valencia, Spain
| | - Ignacio Torres
- Microbiology Service, Hospital Clínico Universitario, Instituto de Investigación INCLIVA, Valencia, Spain
| | - Nieves Orta
- Microbiology Unit, Hospital Francisco de Borja, Gandía, Spain
| | | | - Josep Prat
- Microbiology Unit, Hospital de Sagunto, Spain
| | - David Navarro
- Microbiology Service, Hospital Clínico Universitario, Instituto de Investigación INCLIVA, Valencia, Spain; Department of Microbiology, School of Medicine, University of Valencia, Valencia, Spain.
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Luukinen BV, Vuento R, Hirvonen JJ. Evaluation of two tuberculosis PCR assays for routine use in a clinical setting of low population and low tuberculosis prevalence. APMIS 2019; 127:462-467. [PMID: 30901113 DOI: 10.1111/apm.12947] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Accepted: 03/14/2019] [Indexed: 11/28/2022]
Abstract
Today, there are numerous different molecular diagnostic assays for the detection of tuberculosis (TB), allowing the optimization of rapid detection of TB according to the clinical need. In this study, two high-throughput TB PCR assays with combined antimicrobial resistance detection, Anyplex™ II MTB/MDR (Seegene) and RealTime MTB + RealTime MTB RIF/INH Resistance (Abbott Molecular), were evaluated for routine use in a clinical setting of low population and low TB prevalence in Finland. The RealTime MTB assay was 100% concordant (22/22 positive, n = 169) with the reference methods (culture and Xpert MTB/RIF PCR assay, Cepheid). However, with a limitation of four separate PCR cycles per kit, the routine use in a low TB-prevalence setting would easily lead to wasting most of the RIF/INH Resistance reagents. The Anyplex™ II MTB/MDR assay usability was more adaptive to suit the clinical setting but the assay sensitivity was considerably lower (86%, 19/22 positive, n = 76) being closer to the sensitivity of smear microscopy. The findings of this study suggest that the evaluated high-throughput MTB/MDR assays are evidently suboptimal for routine use in a low population, low TB-prevalence setting. In addition, neither of the two assays covers non-tuberculous mycobacteria and could therefore not fully replace acid-fast staining as the initial screening method.
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Affiliation(s)
- Bruno Vincent Luukinen
- Department of Clinical Microbiology, Fimlab Laboratories Ltd., Tampere, Finland.,Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Risto Vuento
- Department of Clinical Microbiology, Fimlab Laboratories Ltd., Tampere, Finland
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Wang MG, Xue M, Wu SQ, Zhang MM, Wang Y, Liu Q, Sandford AJ, He JQ. Abbott RealTime MTB and MTB RIF/INH assays for the diagnosis of tuberculosis and rifampicin/isoniazid resistance. INFECTION GENETICS AND EVOLUTION 2019; 71:54-59. [PMID: 30902741 DOI: 10.1016/j.meegid.2019.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 03/18/2019] [Accepted: 03/18/2019] [Indexed: 02/05/2023]
Abstract
BACKGROUND The Abbott RealTime MTB (Abbott-RT) and Abbott RealTime MTB RIF/INH Resistance (Abbott-RIF/INH) assays have been introduced for the detection of tuberculosis (TB) and drug-resistant tuberculosis (DR-TB). We performed a systematic review and meta-analysis to assess the accuracy of Abbott-RT and Abbott-RIF/INH for the detection of TB and DR-TB. METHODS The Ovid MEDLINE, EMBASE, Cochrane and Web of Science databases were searched to identify eligible articles for the systematic review. The pooled analyses were calculated with a bivariate model. Hierarchical summary receiver operating characteristic curves and the area under the curve (AUC) were used to summarize overall diagnostic performance. Deeks' test was performed to evaluate potential publication bias. RESULTS For the Abbott-RT assay, 9 studies including 3, 640 patients met the study criteria. The pooled sensitivity of Abbott-RT for detecting TB was 0.96 (95% CI: 0.88-0.99) and specificity was 0.97 (95% CI: 0.93-0.99). For DR-TB, four studies were included to evaluate the diagnosis accuracy of Abbott-RIF/INH. The pooled sensitivity was 0.88 (95% CI, 0.82-0.93) and specificity was 0.99 (95% CI, 0.96-0.99). No publication bias was found. CONCLUSION Both Abbott-RT and Abbott-RIF/INH assays have good sensitivity, specificity and accuracy for the diagnosis of TB and DR-TB.
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Affiliation(s)
- Ming-Gui Wang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Miao Xue
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Shou-Quan Wu
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Miao-Miao Zhang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Yu Wang
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, China
| | - Qianqian Liu
- Department of Respiratory Diseases, Chengdu Municipal First People's Hospital, Chengdu 610041, China
| | - Andrew J Sandford
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul's Hospital, Vancouver V6T 1Z4, Canada
| | - Jian-Qing He
- Department of Respiratory and Critical Care Medicine, West China Hospital, Sichuan University, Chengdu 610041, China.
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13
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Machado D, Couto I, Viveiros M. Advances in the molecular diagnosis of tuberculosis: From probes to genomes. INFECTION GENETICS AND EVOLUTION 2018; 72:93-112. [PMID: 30508687 DOI: 10.1016/j.meegid.2018.11.021] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 11/25/2018] [Accepted: 11/29/2018] [Indexed: 11/29/2022]
Abstract
Tuberculosis, disease caused by Mycobacterium tuberculosis, is currently the leading cause of death by a single infectious agent worldwide. Early, rapid and accurate identification of M. tuberculosis and the determination of drug susceptibility is essential for the treatment and management of this disease. Tuberculosis diagnosis is mainly based on chest radiography, smear microscopy and bacteriological culture. Smear microscopy has variable sensitivity, mainly in patients co-infected with the human immunodeficiency virus (HIV). Conventional culture for M. tuberculosis isolation, identification and drug susceptibility testing requires several weeks owning to the slow growth of M. tuberculosis. The delay in the time to results drives the prolongation of potentially inappropriate antituberculosis therapy contributing to the emergence of drug resistance, reducing treatment options and increasing treatment duration and associated costs, resulting in increased mortality and morbidity. For these reasons, novel diagnostic methods are need for timely identification of M. tuberculosis and determination of the antibiotic susceptibility profile of the infecting strain. Molecular methods offer enhanced sensitivity and specificity, early detection and the capacity to detect mixed infections. These technologies have improved turnaround time, cost effectiveness and are amenable for point-of-care testing. However, although these methods produce results within hours from sample collection, the phenotypic susceptibility testing is still needed for the determination of drug susceptibility and quantify the susceptibility levels of a given strain towards individual antibiotics. This review presents the history, advances and forthcoming promises in the molecular diagnosis of tuberculosis. An overview on the general principles, diagnostic value and the main advantages and disadvantages of the molecular methods used for the detection and identification of M. tuberculosis and its associated disease, is provided. It will be also discussed how the current phenotypic methods should be used in combination with the genotypic methods for rapid antituberculosis susceptibility testing.
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Affiliation(s)
- Diana Machado
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
| | - Isabel Couto
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal
| | - Miguel Viveiros
- Global Health and Tropical Medicine, GHTM, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Lisboa, Portugal.
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Tagliani E, Nikolayevskyy V, Tortoli E, Cirillo DM. Laboratory diagnosis of tuberculosis. Tuberculosis (Edinb) 2018. [DOI: 10.1183/2312508x.10021318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Kostera J, Leckie G, Abravaya K, Wang H. Performance of the Abbott RealTime MTB RIF/INH resistance assay when used to test Mycobacterium tuberculosis specimens from Bangladesh. Infect Drug Resist 2018; 11:695-699. [PMID: 29785129 PMCID: PMC5955021 DOI: 10.2147/idr.s158953] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction The Abbott RealTime MTB RIF/INH Resistance Assay (RT MTB RIF/INH) is an assay for the detection of rifampicin (RIF)- and/or isoniazid (INH)-resistant Mycobacterium tuberculosis (MTB). The assay can be used to test sputum, bronchial alveolar lavage, and N-Acetyl-L-Cysteine (NALC)/NaOH pellets prepared from these samples. The assay can be used in direct testing mode, or in reflex mode following a MTB positive result produced by its companion assay, Abbott RT MTB. Methods In this study, the direct testing mode was used to test paired sputum and NALC/NaOH pellets prepared from sputum collected from Bangladesh TB patients. One hundred and thirty two paired samples were tested. Results The RT MTB RIF/INH inhibition rate was 0%. One hundred and twenty-two paired samples had results above the assay limit of detection and were analyzed by comparing with results from phenotypic drug sensitivity testing, GeneXpert MTB/RIF (Xpert), and MTBDR plus (Hain). RT MTB RIF/INH results were in good agreement with those of GeneXpert and Hain. Conclusion The ability of this assay to detect RIF and INH resistance may contribute to the global control of multidrug resistant tuberculosis.
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Affiliation(s)
- Joshua Kostera
- Abbott Molecular, Abbott Laboratories, Des Plaines, IL, USA
| | - Gregor Leckie
- Abbott Molecular, Abbott Laboratories, Des Plaines, IL, USA
| | - Klara Abravaya
- Abbott Molecular, Abbott Laboratories, Des Plaines, IL, USA
| | - Hong Wang
- Abbott Molecular, Abbott Laboratories, Des Plaines, IL, USA
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Performance of a Highly Sensitive Mycobacterium tuberculosis Complex Real-Time PCR Assay for Diagnosis of Pulmonary Tuberculosis in a Low-Prevalence Setting: a Prospective Intervention Study. J Clin Microbiol 2018. [PMID: 29540457 DOI: 10.1128/jcm.00116-18] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The potential impact of routine real-time PCR testing of respiratory specimens from patients with presumptive tuberculosis in terms of diagnostic accuracy and time to tuberculosis treatment inception in low-prevalence settings remains largely unexplored. We conducted a prospective intervention cohort study. Respiratory specimens from 1,020 patients were examined by acid-fast bacillus smear microscopy, tested by a real-time Mycobacterium tuberculosis complex PCR assay (Abbott RealTime MTB PCR), and cultured in mycobacterial media. Seventeen patients tested positive by PCR (5 were acid-fast bacillus smear positive and 12 acid-fast bacillus smear negative), and Mycobacterium tuberculosis was recovered from cultures for 12 of them. Patients testing positive by PCR and negative by culture (n = 5) were treated and deemed to have responded to antituberculosis therapy. There were no PCR-negative/culture-positive cases, and none of the patients testing positive for nontuberculous mycobacteria (n = 20) yielded a positive PCR result. The data indicated that routine testing of respiratory specimens from patients with presumptive tuberculosis by the RealTime MTB PCR assay improves the tuberculosis diagnostic yield and may reduce the time to antituberculosis treatment initiation. On the basis of our data, we propose a novel mycobacterial laboratory algorithm for tuberculosis diagnosis.
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17
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Ruiz P, Causse M, Vaquero M, Gutierrez JB, Casal M. Evaluation of a new automated Abbott RealTime MTB RIF/INH assay for qualitative detection of rifampicin/isoniazid resistance in pulmonary and extra-pulmonary clinical samples of Mycobacterium tuberculosis. Infect Drug Resist 2017; 10:463-467. [PMID: 29263682 PMCID: PMC5724413 DOI: 10.2147/idr.s147272] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
A new automated real-time PCR assay for the detection of rifampicin (RIF) and isoniazid (INH) resistance in Mycobacterium tuberculosis (MTB) was evaluated. A total of 163 clinical samples (128 pulmonary and 35 extra-pulmonary) were processed using four PCR assay kits: Abbott RealTime MTB RIF/INH, Genotype MTBDRplus, Xpert/MTB RIF, and Anyplex MTB/MDR. The results of phenotypic drug-susceptibility testing using BACTECMGIT 960 were used as reference. The sensitivity and specificity of the new Abbott RealTime MTB RIF/INH assay in comparison with phenotypic testing was 96.3% (95%CI 87.32%-100%) for RIF and 100% (95%CI 99.3%-100%) for INH; the sensitivity was 78.8% (95%CI 66.8%-90.9%) and the specificity was 100% (95%CI 98.9%-100%). The Abbott RealTime MTB RIF/INH test could be a valid method for detecting the most common mutations in strains resistant to RIF and INH.
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Affiliation(s)
- Pilar Ruiz
- Mycobacteria Reference Center, Department of Microbiology, Faculty of Medicine and Nursing, University of Córdoba, Córdoba, Spain
| | - Manuel Causse
- Microbiology Laboratory, Reina Sofía University Hospital, Córdoba, Spain
| | - Manuel Vaquero
- Mycobacteria Reference Center, Department of Microbiology, Faculty of Medicine and Nursing, University of Córdoba, Córdoba, Spain
| | - Juan Bautista Gutierrez
- Mycobacteria Reference Center, Department of Microbiology, Faculty of Medicine and Nursing, University of Córdoba, Córdoba, Spain.,Microbiology Laboratory, Reina Sofía University Hospital, Córdoba, Spain
| | - Manuel Casal
- Mycobacteria Reference Center, Department of Microbiology, Faculty of Medicine and Nursing, University of Córdoba, Córdoba, Spain.,Microbiology Laboratory, Reina Sofía University Hospital, Córdoba, Spain
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18
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Tam KKG, Leung KSS, To SWC, Siu GKH, Lau TCK, Shek VCM, Tse CWS, Wong SSY, Ho PL, Yam WC. Direct detection of Mycobacterium tuberculosis and drug resistance in respiratory specimen using Abbott Realti m e MTB detection and RIF/INH resistance assay. Diagn Microbiol Infect Dis 2017; 89:118-124. [DOI: 10.1016/j.diagmicrobio.2017.06.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/19/2017] [Accepted: 06/20/2017] [Indexed: 10/19/2022]
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19
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Scott L, David A, Noble L, Nduna M, Da Silva P, Black A, Venter F, Stevens W. Performance of the Abbott RealTi me MTB and MTB RIF/INH Assays in a Setting of High Tuberculosis and HIV Coinfection in South Africa. J Clin Microbiol 2017; 55:2491-2501. [PMID: 28592547 PMCID: PMC5527428 DOI: 10.1128/jcm.00289-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 05/25/2017] [Indexed: 01/31/2023] Open
Abstract
South Africa is a country with a high incidence of tuberculosis (TB), complicated by coinfection with human immunodeficiency virus (HIV). The Xpert MTB/RIF (Cepheid, Sunnyvale, CA, USA) is used in South Africa as the test for the initial diagnosis of TB, and other molecular platforms such as the m2000 (Abbott Molecular, Des Plaines, IL, USA) are widely used for molecular monitoring of HIV load. The latter platform is now also equipped with the RealTime (RT) MTB and RealTime MTB RIF/INH assays for TB and first-line drug resistance screening but has not been evaluated in settings of HIV and TB coinfection. A prospective clinical validation study was conducted at a community health center in Johannesburg, South Africa, and consenting individuals with presumptive pulmonary TB were enrolled. The performance of the Abbott assays was compared with those of the Xpert MTB/RIF, liquid culture, drug susceptibility testing, and clinical case definitions. A statistical analysis was performed on 206 individuals (73% were HIV positive). The sensitivity and specificity of the RT MTB were 82.5% (confidence interval [CI], 67.2 to 92.7) and 93.1% (CI, 86.2 to 97.2) on raw sputum and 77.5% (CI, 61.5 to 89.2) and 95.1% (CI, 88.9 to 98.4) on concentrated sputum, respectively, compared with those from liquid culture. The RT MTB correctly identified 17/35 more smear-negative culture-positive specimens than the Xpert MTB/RIF. Both the RT MTB and the Xpert MTB/RIF displayed sensitivities >70% and specificities >90% in HIV-positive individuals. The available drug resistance results concurred with MTBDRplus and drug susceptibility profiles. The RT MTB assay has similar diagnostic performance to the Xpert MTB/RIF and is suited to testing presumptive TB patients coinfected with HIV. The existing laboratory information system connectivity, training, and technical support make this a viable polyvalent option to scale up TB alongside HIV laboratory testing services in South Africa.
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Affiliation(s)
- Lesley Scott
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Anura David
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- National Priority Program, National Health Laboratory Service, Johannesburg, South Africa
| | - Lara Noble
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Matilda Nduna
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Pedro Da Silva
- National Priority Program, National Health Laboratory Service, Johannesburg, South Africa
| | - Andrew Black
- WITS Reproductive Health and HIV Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Francois Venter
- WITS Reproductive Health and HIV Institute, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- National Priority Program, National Health Laboratory Service, Johannesburg, South Africa
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Vergara Gómez A, González-Martín J, García-Basteiro AL. Xpert® MTB/RIF: Usefulness for the diagnosis of tuberculosis and resistance to rifampicin. Med Clin (Barc) 2017; 149:399-405. [PMID: 28739268 DOI: 10.1016/j.medcli.2017.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/05/2017] [Accepted: 06/06/2017] [Indexed: 11/19/2022]
Abstract
The advent of the Xpert® MTB/RIF technique was a revolution in the diagnosis of tuberculosis, especially in areas with high incidence and low resources. It allows the detection of Mycobacterium tuberculosis complex and simultaneously the most common resistance mutations to rifampicin in less than 2h. For respiratory samples the sensitivity is very high, but it decreases for extrapulmonary samples and children. Although it is faster and simpler than conventional methods, it presents some limitations and new and better techniques are needed to reduce the number of cases and deaths caused by tuberculosis. This review aims to assess the scientific evidence around the diagnostic performance of Xpert® MTB/RIF in different types of samples and populations, as well as analyse its strengths and limitations for TB diagnosis.
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Affiliation(s)
- Andrea Vergara Gómez
- Servicio de Microbiología, CDB, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, España
| | - Julià González-Martín
- Servicio de Microbiología, CDB, Hospital Clínic de Barcelona, Universitat de Barcelona, Barcelona, España; Institut de Salut Global de Barcelona (ISGlobal), Barcelona, España
| | - Alberto L García-Basteiro
- Institut de Salut Global de Barcelona (ISGlobal), Barcelona, España; Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique; Amsterdam Institute for Global Health and Development (AIGHD), Ámsterdam, Países Bajos.
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21
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Hinić V, Feuz K, Turan S, Berini A, Frei R, Pfeifer K, Goldenberger D. Clinical evaluation of the Abbott RealTime MTB Assay for direct detection of Mycobacterium tuberculosis-complex from respiratory and non-respiratory samples. Tuberculosis (Edinb) 2017; 104:65-69. [PMID: 28454651 DOI: 10.1016/j.tube.2017.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 02/27/2017] [Accepted: 03/02/2017] [Indexed: 10/20/2022]
Abstract
Rapid and reliable diagnosis is crucial for correct management of tuberculosis. The Abbott RealTime MTB Assay represents a novel qualitative real-time PCR assay for direct detection of M. tuberculosis-complex (MTB) DNA from respiratory samples. The test targets two highly conserved sequences, the multi-copy insertion element IS6110 and the protein antigen B (PAB) gene of MTB, allowing even the detection of IS6610-deficient strains. We evaluated this commercial diagnostic test by analyzing 200 respiratory and, for the first time, 87 non-respiratory clinical specimens from our tertiary care institution and compared its results to our IS6110-based in-house real-time PCR for MTB as well as MTB culture. Overall sensitivity for Abbott RealTime MTB was 100% (19/19) in smear positive and 87.5% (7/8) in smear negative specimens, while the specificity of the assay was 100% (260/260). For both non-respiratory smear positive and smear negative specimens Abbott RealTime MTB tests showed 100% (8/8) sensitivity and 100% (8/8) specificity. Cycle threshold (Ct) value analysis of 16 MTB positive samples showed a slightly higher Ct value of the Abbott RealTime MTB test compared to our in-house MTB assay (mean delta Ct = 2.55). In conclusion, the performance of the new Abbott RealTime MTB Assay was highly similar to culture and in-house MTB PCR. We document successful analysis of 87 non-respiratory samples with the highly automated Abbott RealTime MTB test with no inhibition observed.
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Affiliation(s)
- Vladimira Hinić
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
| | - Kinga Feuz
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
| | - Selda Turan
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
| | - Andrea Berini
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
| | - Reno Frei
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
| | - Karin Pfeifer
- Abbott Molecular, Max-Planck-Ring 2, 65205 Wiesbaden, Germany.
| | - Daniel Goldenberger
- Division of Clinical Microbiology, University Hospital Basel, Petersgraben 4, 4031 Basel, Switzerland.
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Fisher M, Dolby T, Surtie S, Omar G, Hapeela N, Basu D, DeWalt A, Kelso D, Nicol M, McFall S. Improved method for collection of sputum for tuberculosis testing to ensure adequate sample volumes for molecular diagnostic testing. J Microbiol Methods 2017; 135:35-40. [PMID: 28159630 DOI: 10.1016/j.mimet.2017.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/12/2017] [Accepted: 01/23/2017] [Indexed: 11/29/2022]
Abstract
The quality and quantity of sputum collected has an important impact on the laboratory diagnosis of pulmonary TB. We conducted a pilot study to assess a new collection cups for the collection of sputum for the diagnosis of pulmonary tuberculosis. The pilot study utilized the standard collection cup in South Africa demonstrating a mean collection volume of 2.86±2.36SDml for 198 samples; 19% of the specimens contained <1ml and 12% contained >5ml. We designed and tested two novel sputum cups with a narrow bottom section and clear minimum and maximum markings to allow patients and clinicians to know whether sufficient sputum volume has been produced. The cups differed in their shape and manufacturing approach. The two options also support different mixing approaches being considered for a highly sensitive companion TB-screening assay being developed at Northwestern University (XtracTB assay). Sputum was collected from 102 patients at Nolungile Youth Centre, Khayelitsha, Cape Town, South Africa for a total of 204 samples. The mean volumes collected from the two cups were 2.70±0.88SDml and 2.88±0.89SDml. While the mean volumes of current and novel cups are similar, the volume ranges collected with the novel cups were narrower, and 98% of the specimen volumes were within the target range. Only 4 samples contained >5ml, but none were >6ml, and none of the specimens contained <1ml. The number of coughs that produced the samples, patient HIV and TB status plus qualitative descriptions of the sputum specimens were also evaluated.
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Affiliation(s)
| | - Tania Dolby
- University of Cape Town, Cape Town, South Africa
| | | | | | | | - Debby Basu
- Northwestern University, Evanston, IL, USA
| | | | | | - Mark Nicol
- University of Cape Town, Cape Town, South Africa
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Morales-López SE, Yepes JA, Anzola I, Aponte H, Llerena-Polo CR. Paradoxical results of two automated real-time PCR assays in the diagnosis of pleural tuberculosis. Int J Infect Dis 2017; 54:36-38. [DOI: 10.1016/j.ijid.2016.11.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 11/09/2016] [Accepted: 11/11/2016] [Indexed: 10/20/2022] Open
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Kostera J, Leckie G, Tang N, Lampinen J, Szostak M, Abravaya K, Wang H. Analytical and clinical performance characteristics of the Abbott RealTime MTB RIF/INH Resistance, an assay for the detection of rifampicin and isoniazid resistant Mycobacterium tuberculosis in pulmonary specimens. Tuberculosis (Edinb) 2016; 101:137-143. [DOI: 10.1016/j.tube.2016.09.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 09/15/2016] [Indexed: 10/21/2022]
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25
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Evaluation of the Abbott RealTime MTB and RealTime MTB INH/RIF Assays for Direct Detection of Mycobacterium tuberculosis Complex and Resistance Markers in Respiratory and Extrapulmonary Specimens. J Clin Microbiol 2016; 54:3022-3027. [PMID: 27733630 DOI: 10.1128/jcm.01144-16] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/11/2016] [Indexed: 11/20/2022] Open
Abstract
The Abbott RealTime MTB (RT MTB) assay is a new automated nucleic acid amplification test for the detection of Mycobacterium tuberculosis complex (MTBC) in clinical specimens. In combination with the RealTime MTB INH/RIF (RT MTB INH/RIF) resistance assay, which can be applied to RT MTB-positive specimens as an add-on assay, the tests also indicate the genetic markers of resistance to isoniazid (INH) and rifampin (RIF). We aimed to evaluate the diagnostic sensitivity and specificity of RT MTB using different types of respiratory and extrapulmonary specimens and to compare performance characteristics directly with those of the FluoroType MTB assay. The resistance results obtained by RT MTB INH/RIF were compared to those from the GenoType MTBDRplus and from phenotypic drug susceptibility testing. A total of 715 clinical specimens were analyzed. Compared to culture, the overall sensitivity of RT MTB was 92.1%; the sensitivity rates for smear-positive and smear-negative samples were 100% and 76.2%, respectively. The sensitivities of smear-negative specimens were almost identical for respiratory (76.3%) and extrapulmonary (76%) specimens. Specificity rates were 100% and 95.8% for culture-negative specimens and those that grew nontuberculous mycobacteria, respectively. RT MTB INH/RIF was applied to 233 RT MTB-positive samples and identified resistance markers in 7.7% of samples. Agreement with phenotypic and genotypic drug susceptibility testing was 99.5%. In conclusion, RT MTB and RT MTB INH/RIF allow for the rapid and accurate diagnosis of tuberculosis (TB) in different types of specimens and reliably indicate resistance markers. The strengths of this system are the comparably high sensitivity with paucibacillary specimens, its ability to detect INH and RIF resistance, and its high-throughput capacities.
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