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Cheng X, Chen L, Wan W, Peng J, Wu L, Xin J, Cai J. Comparison of 3 diagnostic methods for pulmonary tuberculosis in suspected patients with negative sputum smear or no sputum. Medicine (Baltimore) 2024; 103:e37039. [PMID: 38335388 PMCID: PMC10860950 DOI: 10.1097/md.0000000000037039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Revised: 12/25/2023] [Accepted: 01/03/2024] [Indexed: 02/12/2024] Open
Abstract
STUDY DESIGN To explore the diagnostic value of 3 methods for sputum smear-negative and non-sputum patients with suspected pulmonary tuberculosis (TB). METHODS This prospective study enrolled sputum smear-negative and non-sputum patients with suspected TB admitted to Jiangxi Chest Hospital between January 2020 and December 2022. The 3 methods were bronchoalveolar lavage fluid (BALF)-acid-fast bacillus (AFB) smear, GeneXpert MTB/RIF, and gene chip for Mycobacterium strain identification. The diagnostic performance of the 3 tests was evaluated with BALF Mycobacterium culture + BALF-AFB smear + GeneXpert MTB/RIF + Gene chip as the gold standard. RESULTS A total of 456 samples were collected from 114 patients with suspected TB. Twenty-four patients were diagnosed with TB. The combination of GeneXpert MTB/RIF and gene chip for Mycobacterium strain identification yielded the highest area under the receiver operating characteristics curve (AUC) of 0.953 and had sensitivity of 90.57%, specificity of 100%, positive predictive value (PPV) of 100%, negative predictive value (NPV) of 92.42%, accuracy of 95.61%. GeneXpert MTB/RIF achieved AUC of 0.906, sensitivity of 81.13%, specificity of 100%, PPV of 100%, NPV of 85.92%, accuracy of 91.23%. BALF-AFB smear had AUC of 0.519, sensitivity of 3.77%, specificity of 100%, PPV of 100%, NPV of 54.46%, and accuracy of 55.26%. The combination of GeneXpert MTB/RIF and gene chip for Mycobacterium strain identification yielded the highest κ of 0.911, while BALF-AFB smear had the lowest κ value of 0.040. CONCLUSION For TB in sputum smear-negative and non-sputum patients using BALF Mycobacterium culture + BALF-AFB smear + GeneXpert MTB/RIF + Gene chip as the gold standard, BALF-AFB smear showed low diagnostic performance, while, though GeneXpert MTB/RIF and gene chip had good diagnostic performance, combining GeneXpert MTB/RIF and gene chip improved the diagnostic value to a great extent.
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Affiliation(s)
- Xiaopeng Cheng
- Department of Respiratory and Critical Care Medicine, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
| | - Lerong Chen
- Department of Respiratory and Critical Care Medicine, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
| | - Wenli Wan
- Department of Respiratory and Critical Care Medicine, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
| | - Jianping Peng
- Department of Respiratory and Critical Care Medicine, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
| | - Liangliang Wu
- Department of Respiratory and Critical Care Medicine, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
| | - Jing Xin
- Department of Respiratory and Critical Care Medicine, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
| | - Jianying Cai
- Disinfection supply center, Jiangxi Chest Hospital, Nanchang City, Jiangxi Province, China
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Li K, Hu Q, Liu J, Liu S, He Y. Effects of sputum bacillary load and age on GeneXpert and traditional methods in pulmonary tuberculosis: a 4-year retrospective comparative study. BMC Infect Dis 2023; 23:831. [PMID: 38012541 PMCID: PMC10680317 DOI: 10.1186/s12879-023-08832-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Accepted: 11/18/2023] [Indexed: 11/29/2023] Open
Abstract
BACKGROUND The purpose of this study was to evaluate the diagnostic value of the GeneXpert® MTB/RIF (Xpert®), Auramine O staining method, and Lowenstein-Jensen medium for bacteriologically confirmed pulmonary tuberculosis and explore the effects of the sputum bacillary load (SBL) and qRT‒PCR threshold cycle (Ct) value on the detection methods. METHODS We retrospectively analysed the results in the Department of Infectious Disease for 49 months. The χ2 test was used to compare the performances of each method, receiver operating characteristic curve analysis was used to determine the optimal cut-off values, and the factors associated with a false-negative result from Xpert® were analysed by logistic regression. RESULTS Simultaneous analysis of 980 sputum specimens showed that the positive detection rate of Xpert® did not increase with increasing SBL, and there were differences between the three when SBL ≤ 1 + (all P < 0.05). There was a good negative correlation between the Ct value and the SBL (P < 0.0001). Age was an independent risk factor for false-negative Xpert® results (P = 0.029), and when Ct < 16, the diagnostic sensitivity and specificity were both 100.00%. The optimal cut-off Ct values for resegmentation based on the drug resistance classification were < 18.6, 18.6-34.1, and > 34.1 cycles. CONCLUSIONS Xpert® was not affected by SBL but it was by age, and it is more advantageous when SBL ≤ 1 + . The results regarding rifampicin resistance were reliable, and the novel Ct segmentation was a practical and more clinically meaningful classification method for diagnosing rifampicin resistance. These findings will help improve physicians' ability to accurately diagnose TB.
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Affiliation(s)
- Kui Li
- Department of Infectious Diseases, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West YantaRoad, Xi'an, Shaanxi Province, 710061, China
- Department of Infectious Diseases, Ankang Central Hospital, 85 South Jinzhou Road, Ankang, Shaanxi Province, 725000, China
| | - Qianqian Hu
- Laboratory of Molecular Pathology and Tuberculosis Diseases, Ankang Central Hospital, 85 South Jinzhou Road, Ankang, Shaanxi Province, 725000, China
| | - Jun Liu
- Laboratory of Molecular Pathology and Tuberculosis Diseases, Ankang Central Hospital, 85 South Jinzhou Road, Ankang, Shaanxi Province, 725000, China
| | - Siyi Liu
- Department of Infectious Diseases, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West YantaRoad, Xi'an, Shaanxi Province, 710061, China
| | - Yingli He
- Department of Infectious Diseases, The First Affiliated Hospital of Xi'an Jiaotong University, 277 West YantaRoad, Xi'an, Shaanxi Province, 710061, China.
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van Griensven J, Diro E, Yansouni CP. Hidden sources of bias in diagnostic studies: the example of visceral leishmaniasis in east Africa. THE LANCET. INFECTIOUS DISEASES 2023; 23:e108-e114. [PMID: 36400065 DOI: 10.1016/s1473-3099(22)00643-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 11/17/2022]
Abstract
A clear understanding of the accuracy of diagnostic tests is essential for the management of infections such as visceral leishmaniasis in endemic areas. Using both published and unpublished datasets from field diagnostic trials of visceral leishmaniasis in the past ten years, we show the potential effects of unrecognised sources of bias including work-up bias, referral bias, and reference test bias on the results. We outline why these biases, which can occur in diagnostic studies of any disease, can go unrecognised despite adherence to current STARD and QUADAS-2 guidelines. Using these examples and referring to others seen in studies of bacterial and viral infections, we make specific recommendations on how these biases might be avoided through specific steps in study design, study reporting, and the locations where studies are conducted.
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Affiliation(s)
- Johan van Griensven
- Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
| | - Ermias Diro
- Department of Medicine, Division of General Internal Medicine, University of Washington, Seattle, WA, USA
| | - Cedric P Yansouni
- J D MacLean Centre for Tropical Diseases, McGill University Health Centre, Montreal, QC, Canada; Division of Infectious Diseases and Medical Microbiology, McGill University Health Centre, Montreal, QC, Canada
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Lee JH, Garg T, Lee J, McGrath S, Rosman L, Schumacher SG, Benedetti A, Qin ZZ, Gore G, Pai M, Sohn H. Impact of molecular diagnostic tests on diagnostic and treatment delays in tuberculosis: a systematic review and meta-analysis. BMC Infect Dis 2022; 22:940. [PMID: 36517736 PMCID: PMC9748908 DOI: 10.1186/s12879-022-07855-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 11/08/2022] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Countries with high TB burden have expanded access to molecular diagnostic tests. However, their impact on reducing delays in TB diagnosis and treatment has not been assessed. Our primary aim was to summarize the quantitative evidence on the impact of nucleic acid amplification tests (NAAT) on diagnostic and treatment delays compared to that of the standard of care for drug-sensitive and drug-resistant tuberculosis (DS-TB and DR-TB). METHODS We searched MEDLINE, EMBASE, Web of Science, and the Global Health databases (from their inception to October 12, 2020) and extracted time delay data for each test. We then analysed the diagnostic and treatment initiation delay separately for DS-TB and DR-TB by comparing smear vs Xpert for DS-TB and culture drug sensitivity testing (DST) vs line probe assay (LPA) for DR-TB. We conducted random effects meta-analyses of differences of the medians to quantify the difference in diagnostic and treatment initiation delay, and we investigated heterogeneity in effect estimates based on the period the test was used in, empiric treatment rate, HIV prevalence, healthcare level, and study design. We also evaluated methodological differences in assessing time delays. RESULTS A total of 45 studies were included in this review (DS = 26; DR = 20). We found considerable heterogeneity in the definition and reporting of time delays across the studies. For DS-TB, the use of Xpert reduced diagnostic delay by 1.79 days (95% CI - 0.27 to 3.85) and treatment initiation delay by 2.55 days (95% CI 0.54-4.56) in comparison to sputum microscopy. For DR-TB, use of LPAs reduced diagnostic delay by 40.09 days (95% CI 26.82-53.37) and treatment initiation delay by 45.32 days (95% CI 30.27-60.37) in comparison to any culture DST methods. CONCLUSIONS Our findings indicate that the use of World Health Organization recommended diagnostics for TB reduced delays in diagnosing and initiating TB treatment. Future studies evaluating performance and impact of diagnostics should consider reporting time delay estimates based on the standardized reporting framework.
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Affiliation(s)
- Jae Hyoung Lee
- grid.21107.350000 0001 2171 9311Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Tushar Garg
- grid.21107.350000 0001 2171 9311Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, USA
| | - Jungsil Lee
- grid.8991.90000 0004 0425 469XLondon School of Hygiene & Tropical Medicine, London, UK
| | - Sean McGrath
- grid.38142.3c000000041936754XDepartment of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, USA
| | - Lori Rosman
- grid.21107.350000 0001 2171 9311Welch Medical Library, John Hopkins University School of Medicine, Baltimore, USA
| | - Samuel G. Schumacher
- grid.452485.a0000 0001 1507 3147Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | - Andrea Benedetti
- grid.14709.3b0000 0004 1936 8649Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, Canada ,grid.63984.300000 0000 9064 4811Respiratory Epidemiology & Clinical Research Unit, McGill University Health Centre, Montreal, Canada
| | | | - Genevieve Gore
- grid.14709.3b0000 0004 1936 8649Schulich Library of Physical Sciences, Life Sciences, and Engineering, McGill University, Montreal, Canada
| | - Madhukar Pai
- grid.14709.3b0000 0004 1936 8649McGill International TB Centre, McGill University, Montreal, Canada
| | - Hojoon Sohn
- grid.31501.360000 0004 0470 5905Department of Preventive Medicine, College of Medicine, Seoul National University, Seoul, South Korea
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Bian Y, Deng M, Zhang Q, Hou G. Global trends of research on tuberculous pleurisy over the past 15 years: A bibliometric analysis. Front Cell Infect Microbiol 2022; 12:937811. [PMID: 36111237 PMCID: PMC9468418 DOI: 10.3389/fcimb.2022.937811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 07/28/2022] [Indexed: 11/17/2022] Open
Abstract
Tuberculous pleurisy (TP) is a common type of extrapulmonary tuberculosis (EPTB). With the development of research and changes in TP patient characteristics, an increasing number of studies have revealed the prevalence, risk factors, and novel diagnosis techniques. Thus, this bibliometric analysis was performed to identify global scientific output characteristics and research hotspots and frontiers for TP over the past 15 years. We searched the Web of Science Core Collection (WoSCC) Science Citation Index Expanded (SCI-expanded) for literature published between 2007 and 2021 and recorded their information. The Bibliometrix software package was used for bibliometric indicator analysis, and VOSviewer was used to visualize the trends of and hotspots in TP research. A total of 1,464 original articles were reviewed, and the results indicated that the annual number of publications (Np) focusing on TP has increased over the past 15 years. China had the largest number of papers and the highest H-index, and the United States ranked first for number of citations (Nc). EGYPTIAN KNOWLEDGE BANK and PLOS ONE were the most prolific unit and journal, respectively. The use of the Xpert assay and immune-related biomarker detection to diagnose TP appears to be a recent research hotspot. This bibliometric study demonstrated that the number of publications related to TP have tended to increase. China is a major producer, and the United States is an influential country in this field. Research in the past 15 years has been predominantly clinical research. The diagnosis of TP was the focus of research, and the exploration of novel diagnostic techniques, verification of diagnostic markers, and combination of diagnostic methods have been recent research hotspots. Immune-related biomarkers should be given more attention in the field of TP diagnosis.
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Affiliation(s)
- Yiding Bian
- Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- National Center for Respiratory Medicine, Beijing, China
- Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Beijing, China
- National Clinical Research Center for Respiratory Diseases, Beijing, China
| | - Mingming Deng
- Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- National Center for Respiratory Medicine, Beijing, China
- Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Beijing, China
- National Clinical Research Center for Respiratory Diseases, Beijing, China
| | - Qin Zhang
- Department of Pulmonary and Critical Care Medicine, First Hospital of China Medical University, Shenyang, China
| | - Gang Hou
- Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
- National Center for Respiratory Medicine, Beijing, China
- Institute of Respiratory Medicine, Chinese Academy of Medical Sciences, Beijing, China
- National Clinical Research Center for Respiratory Diseases, Beijing, China
- *Correspondence: Gang Hou,
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Keikha M, Karbalaei M. High resolution melting assay as a reliable method for diagnosing drug-resistant TB cases: a systematic review and meta-analysis. BMC Infect Dis 2021; 21:989. [PMID: 34551717 PMCID: PMC8456628 DOI: 10.1186/s12879-021-06708-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2021] [Accepted: 09/11/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Tuberculosis (TB) is one of the most contagious infectious diseases worldwide. Currently, drug-resistant Mycobacterium tuberculosis (Mtb) isolates are considered as one of the main challenges in the global TB control strategy. Rapid detection of resistant strains effectively reduces morbidity and mortality of world's population. Although both culture and conventional antibiotic susceptibility testing are time-consuming, recent studies have shown that high resolution melting (HRM) assay can be used to determine the types of antibiotic resistance. In the present meta-analysis, we evaluated the discriminative power of HRM in detecting all drug-resistance cases of TB. METHODS A systematic search was performed using databases such as Cochrane Library, Scopus, PubMed, Web of Science, and Google Scholar. Related studies on the effect of HRM in the diagnosis of drug-resistant (DR) TB cases were retrieved by April 2021. We used Meta-Disc software to evaluate the pooled diagnostic sensitivity and specificity of HRM for the detection of each type of drug-resistant cases. Finally, diagnostic value of HRM was characterized by summary receiver operating characteristic (SROC) curve and the area under the curve (AUC) method. RESULTS Overall 47 studies (4,732 Mtb isolates) met our criteria and were included in the present meta-analysis. Sensitivity, specificity, and AUC of HRM were measured for antibiotics such as isoniazid (93%, 98%, 0.987), rifampin (94%, 97%, 0963), ethambutol (82%, 87%, 0.728), streptomycin (82%, 95%, 0.957), pyrazinamide (72%, 84%, 0.845), fluoroquinolones (86%, 99%, 0.997), MDR-TB (90%, 98%, 0.989), and pan-drug-resistant TB (89%, 95%, 0.973). CONCLUSIONS The HRM assay has high accuracy for the identification of drug-resistant TB, particularly firs-line anti-TB drugs. Therefore, this method is considered as an alternative option for the rapid diagnosis of DR-TB cases. However, due to heterogeneity of included studies, the results of HRM assays should be interpreted based on conventional drug susceptibility testing.
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Affiliation(s)
- Masoud Keikha
- Department of Microbiology and Virology, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
- Student Research Committee, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohsen Karbalaei
- Department of Microbiology and Virology, School of Medicine, Jiroft University of Medical Sciences, Jiroft, Iran.
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GeneXpert on patients with human immunodeficiency virus and smear-negative pulmonary tuberculosis. PLoS One 2021; 16:e0253961. [PMID: 34228759 PMCID: PMC8259960 DOI: 10.1371/journal.pone.0253961] [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: 08/27/2020] [Accepted: 06/17/2021] [Indexed: 11/25/2022] Open
Abstract
Objectives Vietnam is a high-prevalence country for tuberculosis (TB). Xpert MTB/RIF is a novel PCR-based diagnostic test that is substantially more sensitive for detecting M. tuberculosis than traditional smear-based techniques. However, locally-derived evidence of Xpert MTB/RIF in HIV-infected people is limited. This study evaluates the performance of the Xpert MTB/RIF in HIV-infected patients with smear-negative pulmonary TB (SNTB). Methods This was a cross-sectional study in 3 hospitals. The performance of Xpert MTB/RIF was compared with the reference standard of liquid culture and phenotypic drug-susceptibility testing for rifampicin (RIF) resistance. Results Out of 123 patients, the median age was 37.0 (IQR: 32.0–41.0) and 81.3% were male. The area under the receiver operating characteristic curve, sensitivity (Se) and specificity (Sp) of Xpert MTB/RIF for pulmonary TB diagnosis were 0.72 (95% confidence interval [CI]: 0.63–0.81), 66.7% (95%CI: 54.8–77.1) and 77.1% (95%CI: 62.7–88.0), respectively, while Se and Sp of Xpert MTB/RIF in detecting RIF resistance were 50.0 (11.8–88.2) and 86.4% (95%CI: 72.7–94.8). Conclusion The performance of Xpert MTB/RIF in HIV-infected patients with SNTB for the diagnosis of TB and RIF-resistance was low. Further studies are required to evaluate the results of Xpert MTB/RIF assay in HIV-infected patients with SNTB and the role of Xpert repetition on the same specimens.
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Lee HN, Kim JI, Kim YH. Clinical and CT characteristics of Xpert MTB/RIF-negative pulmonary tuberculosis. PLoS One 2021; 16:e0250616. [PMID: 33939723 PMCID: PMC8092799 DOI: 10.1371/journal.pone.0250616] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/09/2021] [Indexed: 12/01/2022] Open
Abstract
Purpose To determine the diagnostic accuracy of the Xpert MTB/RIF assay in patients with smear-negative pulmonary tuberculosis (TB) and to assess clinical and CT characteristics of Xpert-negative pulmonary TB. Material and methods We retrospectively reviewed the records of 1,400 patients with suspected pulmonary TB for whom the sputum Xpert MTB/RIF assay was performed between September 1, 2014 and February 28, 2020. Clinical and CT characteristics of smear-negative pulmonary TB patients with negative Xpert MTB/RIF results were compared with positive results. Results Of 1,400 patients, 365 (26.1%) were diagnosed with pulmonary TB and 190 of 365 patients (52.1%) were negative for sputum acid-fast bacilli. The diagnosis of pulmonary TB was based on a positive culture, positive Xpert MTB/RIF or the clinical diagnoses of patients treated with an anti-TB medication. The sensitivity, specificity, positive predictive and negative predictive values of sputum Xpert MTB/RIF for smear-negative pulmonary TB were 41.1%, 100%, 100%, and 90.1%, respectively. Finally, 172 patients with smear-negative pulmonary TB who underwent chest CT within 2 weeks of diagnosis were included to compare Xpert-positive (n = 66) and Xpert- negative (n = 106) groups. Patients with sputum Xpert-negative TB showed lower positive rates for sputum culture (33.0% vs. 81.8%, p<0.001) and bronchoalveolar lavage culture (53.3% vs. 84.6%, p = 0.042) than in Xpert-positive TB. Time to start TB medication was longer in patients with Xpert-negative TB than in Xpert-positive TB (11.3±16.4 days vs. 5.0±8.7 days, p = 0.001). On chest CT, sputum Xpert-negative TB showed significantly lower frequency of consolidation (21.7% vs. 39.4%, p = 0.012), cavitation (23.6% vs. 37.9%, p = 0.045), more frequent peripheral location (50.9% vs. 21.2 p = 0.001) with lower area of involvement (4.3±4.3 vs. 7.6±6.4, p<0.001). Multivariate analysis revealed peripheral location (odds ratios, 2.565; 95% confidence interval: 1.157–5.687; p = 0.020) and higher total extent of the involved lobe (odds ratios, 0.928; 95% confidence interval: 0.865–0.995; p = 0.037) were significant factors associated with Xpert MTB/RIF-negative TB. Regardless of Xpert positivity, more than 80% of all cases were diagnosed of TB on chest CT by radiologists. Conclusion The detection rate of sputum Xpert MTB/RIF assay was relatively low for smear negative pulmonary TB. Chest CT image interpretation may play an important role in early diagnosis and treatment of Xpert MTB/RIF-negative pulmonary TB.
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Affiliation(s)
- Han Na Lee
- Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Republic of Korea
- * E-mail:
| | - Jung Im Kim
- Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Republic of Korea
| | - Yee Hyung Kim
- Department of Respiratory Medicine, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, Seoul, Republic of Korea
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Meier NR, Battegay M, Ottenhoff THM, Furrer H, Nemeth J, Ritz N. HIV-Infected Patients Developing Tuberculosis Disease Show Early Changes in the Immune Response to Novel Mycobacterium tuberculosis Antigens. Front Immunol 2021; 12:620622. [PMID: 33777000 PMCID: PMC7994263 DOI: 10.3389/fimmu.2021.620622] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/09/2021] [Indexed: 11/13/2022] Open
Abstract
Background: In individuals living with HIV infection the development of tuberculosis (TB) is associated with rapid progression from asymptomatic TB infection to active TB disease. Sputum-based diagnostic tests for TB have low sensitivity in minimal and subclinical TB precluding early diagnosis. The immune response to novel Mycobacterium tuberculosis in-vivo expressed and latency associated antigens may help to measure the early stages of infection and disease progression and thereby improve early diagnosis of active TB disease. Methods: Serial prospectively sampled cryopreserved lymphocytes from patients of the Swiss HIV Cohort Study developing TB disease ("cases") and matched patients with no TB disease ("controls") were stimulated with 10 novel Mycobacterium tuberculosis antigens. Cytokine concentrations were measured in cases and controls at four time points prior to diagnosis of TB: T1-T4 with T4 being the closest time point to diagnosis. Results: 50 samples from nine cases and nine controls were included. Median CD4 cell count at T4 was 289/ul for the TB-group and 456/ul for the control group. Viral loads were suppressed in both groups. At T4 Rv2431c-induced and Rv3614/15c-induced interferon gamma-induced protein (IP)-10 responses and Rv2031c-induced and Rv2346/Rv2347c-induced tumor necrosis factor (TNF)-α responses were significantly higher in cases compared to controls (p < 0.004). At T3 - being up to 2 years prior to TB diagnosis - Rv2031c-induced TNF-α was significantly higher in cases compared to controls (p < 0.004). Area under the receiver operating characteristics (AUROC) curves resulted in an AUC > 0.92 for all four antigen-cytokine pairs. Conclusion: The in vitro Mycobacterium tuberculosis-specific immune response in HIV-infected individuals that progress toward developing TB disease is different from those in HIV-infected individuals that do not progress to developing TB. These differences precede the clinical diagnosis of active TB up to 2 years, paving the way for the development of immune based diagnostics to predict TB disease at an early stage.
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Affiliation(s)
- Noemi Rebecca Meier
- University of Basel Children's Hospital, Mycobacterial Research Laboratory, Basel, Switzerland.,University of Basel, Faculty of Medicine, Basel, Switzerland
| | - Manuel Battegay
- University of Basel, Faculty of Medicine, Basel, Switzerland.,Division of Infectious Diseases and Hospital Epidemiology, University Hospital Basel, University of Basel, Basel, Switzerland
| | - Tom H M Ottenhoff
- Leiden University Medical Center, Department of Infectious Diseases, Leiden, Netherlands
| | - Hansjakob Furrer
- Department of Infectious Diseases, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Johannes Nemeth
- Division of Infectious Diseases, Zürich University Hospital, University of Zürich, Zurich, Switzerland
| | - Nicole Ritz
- University of Basel Children's Hospital, Mycobacterial Research Laboratory, Basel, Switzerland.,University of Basel, Faculty of Medicine, Basel, Switzerland.,University of Basel Children's Hospital, Paediatric Infectious Diseases and Vaccinology Unit, Basel, Switzerland.,Royal Children's Hospital Melbourne, Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia
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Eckbo EJ, Rodrigues M, Hird T, Ng M, Lam K, Sekirov I. Needle in a haystack: Looking for tuberculosis in a low-incidence setting. JOURNAL OF THE ASSOCIATION OF MEDICAL MICROBIOLOGY AND INFECTIOUS DISEASE CANADA = JOURNAL OFFICIEL DE L'ASSOCIATION POUR LA MICROBIOLOGIE MEDICALE ET L'INFECTIOLOGIE CANADA 2021; 6:49-54. [PMID: 36340213 PMCID: PMC9612438 DOI: 10.3138/jammi-2020-0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/26/2020] [Indexed: 06/16/2023]
Abstract
BACKGROUND Canada is a low-incidence country for tuberculosis (TB). The BC Public Health Laboratory diagnostic algorithm for pulmonary TB includes acid fast bacilli (AFB) smear and mycobacterial culture of all submitted sputa. TB nucleic acid amplification testing (NAT) is routinely performed on AFB-smear-positive (AFB+) sputa only. We assessed the laboratory-associated costs of implementing the international recommendations for TB NAT on AFB-smear-negative (AFB-) sputa. METHODS Two data sets were obtained: (1) all AFB- samples for a 3-year period (October 1, 2014-September 30, 2017) and (2) all AFB-, TB-culture-positive samples for the same period. One AFB- sample/patient from each defined diagnostic set of sputa was deemed eligible for TB NAT. To stratify patients by ordering location, a 1-year subset of data (October 1, 2016-September 30, 2017) was examined. RESULTS In the 3-year period, 0.7% of all diagnostic sets were AFB- and culture-positive. In the 1-year period, the provincial TB Services clinics submitted 26% of all AFB- samples received, but these constituted 78% of AFB-, culture-positive samples. CONCLUSIONS The annual cost of TB NAT on one AFB- sputum sample from each eligible diagnostic set would total approximately $247,000. Targeting only TB Services clinic patients would reduce this cost to approximately $64,000/year while capturing more than 75% of AFB-, culture-positive patients. On the basis of our provincial positivity rate, it would cost approximately $6,000 to provide an early TB diagnosis for an AFB-, culture-positive patient. The cost-effectiveness to public health of this approach in a TB low-incidence setting needs to be carefully evaluated.
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Affiliation(s)
- Eric J Eckbo
- Department of Pathology & Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Mabel Rodrigues
- British Columbia Centre for Disease Control, Public Health Laboratory, Vancouver, British Columbia, Canada
| | - Trevor Hird
- British Columbia Centre for Disease Control, Public Health Laboratory, Vancouver, British Columbia, Canada
| | - Monica Ng
- British Columbia Centre for Disease Control, Public Health Laboratory, Vancouver, British Columbia, Canada
| | - Kelvin Lam
- British Columbia Centre for Disease Control, Public Health Laboratory, Vancouver, British Columbia, Canada
| | - Inna Sekirov
- Department of Pathology & Laboratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
- British Columbia Centre for Disease Control, Public Health Laboratory, Vancouver, British Columbia, Canada
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Performance of Xpert MTB/RIF Ultra assay on respiratory and extra-respiratory samples in a high-resource setting with a low tuberculosis prevalence. Diagn Microbiol Infect Dis 2020; 99:115235. [PMID: 33130504 DOI: 10.1016/j.diagmicrobio.2020.115235] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 11/22/2022]
Abstract
The Xpert MTB/RIF assay is a molecular assay that has improved the detection of tuberculosis and rifampicin resistance. However, its sensitivity is limited in patients with paucibacillary disease. Xpert MTB/RIF Ultra has been developed to resolve this limitation. We compared the performance of Xpert Ultra with that of culture for detection of Mycobacterium tuberculosis and rifampicin resistance. We reviewed laboratory records for 848 respiratory and 419 extrarespiratory samples that were processed between April 2018 and October 2019. The sensitivity, specificity, negative predictive value, and positive predictive value of Xpert Ultra were 94.8%, 98%, 98.8%, and 91.3% for respiratory samples and 83.8%, 96.9%, 98.4% and 72.1% for nonrespiratory ones. We found 26 culture-negative/Ultra-positive samples. Most of them have low bacillary burden and more than half belonged to patients with history of tuberculosis. Xpert Ultra demonstrates excellent diagnostic accuracy for tuberculosis detection, including paucibacillary specimens. In patients with history of tuberculosis, PCR results should be interpreted carefully.
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12
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Park M, Kon OM. Use of Xpert MTB/RIF and Xpert Ultra in extrapulmonary tuberculosis. Expert Rev Anti Infect Ther 2020; 19:65-77. [PMID: 32806986 DOI: 10.1080/14787210.2020.1810565] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
INTRODUCTION Tuberculosis (TB) remains a major global health burden. There still remains a large gap between the notified and estimated incident cases. Extrapulmonary (EP) TB represents 15% of all TB cases and the diagnosis is more challenging due to the paucity of the organism. Smear microscopy is often insensitive and culture methods are prolonged. With the introduction of Xpert MTB/RIF and more recently Xpert Ultra, this has changed TB diagnostics by providing a rapid accessible platform to diagnose TB and identify rifampicin resistance within 2 h. AREAS COVERED The diagnostic accuracy and the clinical role of Xpert MTB/RIF and Xpert Ultra in the different forms of EPTB. EXPERT OPINION Whilst significant advances have been made in TB diagnostics, there is still a need to optimize the diagnostic yield of Xpert MTB/RIF and Xpert Ultra in EPTB samples. Research is needed to facilitate standardization and optimal preparation of samples as well as understanding the role of Xpert MTB/RIF and Xpert Ultra in different burden settings. Alongside the current GeneXpert platform, the launch of rapid second-line drug resistance polymerase chain reactions and whole genome sequencing may help tackle the global health burden with a more comprehensive diagnostic approach and appropriate treatment.
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Affiliation(s)
- Mirae Park
- Imperial College Healthcare NHS Trust, St Mary's Hospital , London, UK.,National Heart and Lung Institute, Imperial College London , London, UK
| | - Onn Min Kon
- Imperial College Healthcare NHS Trust, St Mary's Hospital , London, UK.,National Heart and Lung Institute, Imperial College London , London, UK
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13
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Which sample type is better for Xpert MTB/RIF to diagnose adult and pediatric pulmonary tuberculosis? Biosci Rep 2020; 40:225865. [PMID: 32701147 PMCID: PMC7403955 DOI: 10.1042/bsr20200308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 07/16/2020] [Accepted: 07/17/2020] [Indexed: 02/05/2023] Open
Abstract
Objective: This review aimed to identify proper respiratory-related sample types for adult and pediatric pulmonary tuberculosis (PTB), respectively, by comparing performance of Xpert MTB/RIF when using bronchoalveolar lavage (BAL), induced sputum (IS), expectorated sputum (ES), nasopharyngeal aspirates (NPAs), and gastric aspiration (GA) as sample. Methods: Articles were searched in Web of Science, PubMed, and Ovid from inception up to 29 June 2020. Pooled sensitivity and specificity were calculated, each with a 95% confidence interval (CI). Quality assessment and heterogeneity evaluation across included studies were performed. Results: A total of 50 articles were included. The respective sensitivity and specificity were 87% (95% CI: 0.84–0.89), 91% (95% CI: 0.90–0.92) and 95% (95% CI: 0.93–0.97) in the adult BAL group; 90% (95% CI: 0.88–0.91), 98% (95% CI: 0.97–0.98) and 97% (95% CI: 0.95–0.99) in the adult ES group; 86% (95% CI: 0.84–0.89) and 97% (95% CI: 0.96–0.98) in the adult IS group. Xpert MTB/RIF showed the sensitivity and specificity of 14% (95% CI: 0.10–0.19) and 99% (95% CI: 0.97–1.00) in the pediatric ES group; 80% (95% CI: 0.72–0.87) and 94% (95% CI: 0.92–0.95) in the pediatric GA group; 67% (95% CI: 0.62–0.72) and 99% (95% CI: 0.98–0.99) in the pediatric IS group; and 54% (95% CI: 0.43–0.64) and 99% (95% CI: 0.97–0.99) in the pediatric NPA group. The heterogeneity across included studies was deemed acceptable. Conclusion: Considering diagnostic accuracy, cost and sampling process, ES was a better choice than other sample types for diagnosing adult PTB, especially HIV-associated PTB. GA might be more suitable than other sample types for diagnosing pediatric PTB. The actual choice of sample types should also consider the needs of specific situations.
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14
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Jiang J, Yang J, Shi Y, Jin Y, Tang S, Zhang N, Lu Y, Sun G. Head-to-head comparison of the diagnostic accuracy of Xpert MTB/RIF and Xpert MTB/RIF Ultra for tuberculosis: a meta-analysis. Infect Dis (Lond) 2020; 52:763-775. [PMID: 32619114 DOI: 10.1080/23744235.2020.1788222] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Tuberculosis (TB) diagnosis has significantly improved since the introduction of the automated molecular test Xpert MTB/RIF (Xpert) and the new version Xpert MTB/RIF Ultra (Ultra) that detect Mycobacterium tuberculosis. Due to the rapidly widespread use of Xpert and Ultra, we conducted a meta-analysis to compare the performances of Xpert and Ultra in diagnosing TB and discuss the advantages and limitations of these two tests. METHODS Web of Science, Medline (via PubMed), Embase (via OvidSP), the Cochrane Central Register of Controlled Trials and Google Scholar (up to April 2020) were searched for relevant studies. The diagnostic performance of Xpert and Ultra for TB was determined using a bivariate random-effects regression model. The sources of heterogeneity were explored via meta-regression and subgroup analyses. RESULTS Of 19 studies that examined a total of 5855 samples, the pooled sensitivity and specificity of Xpert in TB diagnosis were 0.69 (95% CI: 0.57-0.78) and 0.99 (95% CI: 0.98-0.99), respectively. However, the pooled sensitivity and specificity of Ultra in TB diagnosis were 0.84 (95% CI: 0.76-0.90) and 0.97 (95% CI: 0.96-0.98), respectively. Regardless of whether the comparisons were indirect or direct, Ultra was consistently found to be more sensitive, but with slightly lower specificity than Xpert in diagnosing TB. CONCLUSIONS Compared with Xpert, Ultra had higher sensitivity but slightly lower specificity for the diagnosis of TB disease. The excellent upgrade in sensitivity of the Ultra test was particularly relevant in subjects with paucibacillary TB including tuberculous pleurisy, tuberculous meningitis and paediatric TB.
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Affiliation(s)
- Jianjun Jiang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Jin Yang
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yining Shi
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Yongmei Jin
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Sihui Tang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Na Zhang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Youjin Lu
- Department of Respiratory and Critical Care Medicine, The Second Affiliated Hospital of Anhui Medical University, Hefei, China
| | - Gengyun Sun
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Anhui Medical University, Hefei, China
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15
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Das S, Mangold KA, Shah NS, Peterson LR, Thomson RB, Kaul KL. Performance and Utilization of a Laboratory-Developed Nucleic Acid Amplification Test (NAAT) for the Diagnosis of Pulmonary and Extrapulmonary Tuberculosis in a Low-Prevalence Area. Am J Clin Pathol 2020; 154:115-123. [PMID: 32249294 DOI: 10.1093/ajcp/aqaa031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES Tuberculosis (TB) is a significant global health problem. In low-prevalence areas and low clinical suspicion, nucleic acid amplification tests (NAAT) for direct detection of Mycobacterium tuberculosis complex (MTBC) can speed therapy initiation and infection control. An NAAT assay (TBPCR) targeting MTBC IS6110 is used for detecting MTBC in our low-prevalence population. METHODS Fifteen-year review of patient records identified 146 patients with culture-positive pulmonary tuberculosis (PTB) or extrapulmonary tuberculosis (EPTB). Laboratory-developed TBPCR was retrospectively compared with standard stain and cultures for PTB and EPTB diagnoses. RESULTS TBPCR assay was used in 57% of patients with PTB and 33% of patients with EPTB. TBPCR detected 88.4% of all TB (smear-positive, 97%; smear-negative, 79%) with 100% specificity. Low bacterial load was indicated in TBPCR-negative PTB (P = .002) and EPTB (P < .008). CONCLUSIONS TBPCR performance was optimum but significantly underused. Guidelines are proposed for mandated use of TBPCR that capture patients with clinically suspected PTB. Focused TBPCR use in low prevalence populations will benefit patient care, infection prevention, and public health.
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Affiliation(s)
- Sanchita Das
- Departments of 1Pathology and Laboratory Medicine, Evanston, IL
- Department of Pathology, University of Chicago Pritzker School of Medicine, Chicago, IL
| | - Kathy A Mangold
- Departments of 1Pathology and Laboratory Medicine, Evanston, IL
- Department of Pathology, University of Chicago Pritzker School of Medicine, Chicago, IL
| | - Nirav S Shah
- Medicine, NorthShore University HealthSystem, Evanston, IL
| | - Lance R Peterson
- Departments of 1Pathology and Laboratory Medicine, Evanston, IL
- Department of Pathology, University of Chicago Pritzker School of Medicine, Chicago, IL
- Medicine, NorthShore University HealthSystem, Evanston, IL
| | - Richard B Thomson
- Departments of 1Pathology and Laboratory Medicine, Evanston, IL
- Department of Pathology, University of Chicago Pritzker School of Medicine, Chicago, IL
| | - Karen L Kaul
- Departments of 1Pathology and Laboratory Medicine, Evanston, IL
- Department of Pathology, University of Chicago Pritzker School of Medicine, Chicago, IL
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Higher T-SPOT.TB threshold may aid in diagnosing active tuberculosis?: A real-world clinical practice in a general hospital. Clin Chim Acta 2020; 509:60-66. [PMID: 32505775 DOI: 10.1016/j.cca.2020.06.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/02/2020] [Accepted: 06/03/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND This study aimed to determine whether increased cut-off of the T-SPOT.TB could aid in diagnosing active tuberculosis (ATB). METHODS Patients suspected of having TB were enrolled to derive a T-SPOT.TB threshold value to help diagnose ATB, which was subsequently validated in real-world clinical practice. RESULTS In total, 701 adult patients suspected of having tuberculosis who had undergone the T-SPOT.TB assay were included in the derivation cohort. The numbers of ESAT-6 (U = 43583, P = 0.0002) and CFP-10 (U = 41753, P < 0.0001) spot-forming cells (SFCs) significantly increased in the ATB group compared with the Latent tuberculosis infection (LTBI) group. According to receiver operating characteristic analysis, when a cut-off of 37.5 SFCs/2.5 × 105 cells was used to discriminate between ATB and LTBI, the sensitivity was 57.5% (95% confidence interval [CI] 50.7%-64.2%) and the specificity was 59.8% (95% CI 55.2%-64.2%). A threshold value of 173.5 SFCs/2.5 × 105 could be used to obtain a specificity of <90% to discriminate between ATB and LTBI. The diagnostic accuracy of higher T-SPOT.TB threshold values in the validation cohort was similar to that in the derivation cohort. CONCLUSIONS In high-burden countries, a higher threshold value of 173.5 SFCs/2.5 × 105 may aid in ATB diagnosis in suspected tuberculosis patients.
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17
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Performances and usefulness of Xpert MTB/RIF assay in low-incidence settings: not that bad? Eur J Clin Microbiol Infect Dis 2020; 39:1645-1649. [PMID: 32306143 DOI: 10.1007/s10096-020-03887-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 03/30/2020] [Indexed: 10/23/2022]
Abstract
Xpert MTB/RIF assay, a real-time PCR assay designed to detect Mycobacterium tuberculosis, has proven sensitive and specific when performed on respiratory samples in a high prevalence setting. However, it was suggested as less accurate in a low-incidence environment. We evaluated the accuracy of the Xpert for the diagnosis of tuberculosis (TB) on pulmonary and extrapulmonary samples in Geneva (Switzerland), where the prevalence of active TB is very low. From March 2009 to February 2013, the Xpert was performed on clinical samples. All specimens were also processed using auramine, AFB staining, and mycobacterial culture with both solid and liquid media. The accuracy of both microscopy and Xpert was determined retrospectively using cultures as the reference method. A total of 732 clinical specimens were processed with the Xpert. The Xpert had a high specificity (97.5%; 95% confidence interval (CI), 95.8-98.5%) and revealed much more sensitive (82.7%; 95% CI, 74.1-89.0%) than microscopy (55.5%; 95% CI, 45.7-64.8%) for the diagnosis of TB, with a high negative predictive value (96.8%; 95% CI, 95.0-98.0%). The advantage of PCR over microscopy was even more pronounced for extrapulmonary specimens (sensitivity of 70% (95% CI, 50.4-84.6%) compared with 23.3% (95% CI, 10.6-42.7%)). Despite the low prevalence of TB in Switzerland, results performance for respiratory samples was similar to that reported in high prevalence countries. The high negative predictive value is clinically helpful in our setting, where pulmonary TB needs to be reasonably ruled out. When considering extrapulmonary samples, microscopy performed poorly compared with Xpert. This study shows that the Xpert remains accurate and useful in a low-incidence setting.
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18
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Acharya B, Acharya A, Gautam S, Ghimire SP, Mishra G, Parajuli N, Sapkota B. Advances in diagnosis of Tuberculosis: an update into molecular diagnosis of Mycobacterium tuberculosis. Mol Biol Rep 2020; 47:4065-4075. [DOI: 10.1007/s11033-020-05413-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 03/28/2020] [Indexed: 01/02/2023]
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19
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Chen G, Wang H, Wang Y. Clinical application of QuantiFERON-TB Gold in-tube in the diagnosis and treatment of tuberculosis. Eur J Clin Microbiol Infect Dis 2019; 39:607-612. [PMID: 31786694 DOI: 10.1007/s10096-019-03768-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 11/11/2019] [Indexed: 11/25/2022]
Abstract
At present, although it has made great progress in the diagnosis and treatment of tuberculosis, tuberculosis is still an important cause of morbidity and mortality. There were approximately 8.6 million new cases of tuberculosis in 2012, and approximately 1.3 million people died from tuberculosis. Early diagnosis and timely treatment are essential for controlling the spread of tuberculosis infection and reducing mortality. Conventional methods of Mycobacterium tuberculosis detection such as acid-fast staining microscopy and tuberculin skin test are widely used, but with low sensitivity or specificity. In recent years, a newly developed quantitative test, γ-interferon release test (IGRA), has been recognized and widely applied to the early diagnosis and monitoring of tuberculosis. QuantiFERON-TB Gold in-tube (QFT-GIT) is one of the mature IGRA methods. This paper summarizes the researches on QFT-GIT in recent years and introduces its principles, methodology, clinical application, and factors of uncertain results for the diagnosis and treatment of tuberculosis.
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Affiliation(s)
- Guangming Chen
- Department of General Practice, Jinhua Municipal Central Hospital, Jinhua, People's Republic of China
| | - Huabin Wang
- Central Laboratory, Jinhua Municipal Central Hospital, Jinhua, People's Republic of China.
| | - Yanhong Wang
- Department of Laboratory Medicine, Wenzhou Medical University, Wenzhou, People's Republic of China
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20
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Horne DJ, Kohli M, Zifodya JS, Schiller I, Dendukuri N, Tollefson D, Schumacher SG, Ochodo EA, Pai M, Steingart KR. Xpert MTB/RIF and Xpert MTB/RIF Ultra for pulmonary tuberculosis and rifampicin resistance in adults. Cochrane Database Syst Rev 2019; 6:CD009593. [PMID: 31173647 PMCID: PMC6555588 DOI: 10.1002/14651858.cd009593.pub4] [Citation(s) in RCA: 115] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND Xpert MTB/RIF (Xpert MTB/RIF) and Xpert MTB/RIF Ultra (Xpert Ultra), the newest version, are the only World Health Organization (WHO)-recommended rapid tests that simultaneously detect tuberculosis and rifampicin resistance in persons with signs and symptoms of tuberculosis, at lower health system levels. A previous Cochrane Review found Xpert MTB/RIF sensitive and specific for tuberculosis (Steingart 2014). Since the previous review, new studies have been published. We performed a review update for an upcoming WHO policy review. OBJECTIVES To determine diagnostic accuracy of Xpert MTB/RIF and Xpert Ultra for tuberculosis in adults with presumptive pulmonary tuberculosis (PTB) and for rifampicin resistance in adults with presumptive rifampicin-resistant tuberculosis. SEARCH METHODS We searched the Cochrane Infectious Diseases Group Specialized Register, MEDLINE, Embase, Science Citation Index, Web of Science, Latin American Caribbean Health Sciences Literature, Scopus, the WHO International Clinical Trials Registry Platform, the International Standard Randomized Controlled Trial Number Registry, and ProQuest, to 11 October 2018, without language restriction. SELECTION CRITERIA Randomized trials, cross-sectional, and cohort studies using respiratory specimens that evaluated Xpert MTB/RIF, Xpert Ultra, or both against the reference standard, culture for tuberculosis and culture-based drug susceptibility testing or MTBDRplus for rifampicin resistance. DATA COLLECTION AND ANALYSIS Four review authors independently extracted data using a standardized form. When possible, we also extracted data by smear and HIV status. We assessed study quality using QUADAS-2 and performed meta-analyses to estimate pooled sensitivity and specificity separately for tuberculosis and rifampicin resistance. We investigated potential sources of heterogeneity. Most analyses used a bivariate random-effects model. For tuberculosis detection, we first estimated accuracy using all included studies and then only the subset of studies where participants were unselected, i.e. not selected based on prior microscopy testing. MAIN RESULTS We identified in total 95 studies (77 new studies since the previous review): 86 studies (42,091 participants) evaluated Xpert MTB/RIF for tuberculosis and 57 studies (8287 participants) for rifampicin resistance. One study compared Xpert MTB/RIF and Xpert Ultra on the same participant specimen.Tuberculosis detectionOf the total 86 studies, 45 took place in high tuberculosis burden and 50 in high TB/HIV burden countries. Most studies had low risk of bias.Xpert MTB/RIF pooled sensitivity and specificity (95% credible Interval (CrI)) were 85% (82% to 88%) and 98% (97% to 98%), (70 studies, 37,237 unselected participants; high-certainty evidence). We found similar accuracy when we included all studies.For a population of 1000 people where 100 have tuberculosis on culture, 103 would be Xpert MTB/RIF-positive and 18 (17%) would not have tuberculosis (false-positives); 897 would be Xpert MTB/RIF-negative and 15 (2%) would have tuberculosis (false-negatives).Xpert Ultra sensitivity (95% confidence interval (CI)) was 88% (85% to 91%) versus Xpert MTB/RIF 83% (79% to 86%); Xpert Ultra specificity was 96% (94% to 97%) versus Xpert MTB/RIF 98% (97% to 99%), (1 study, 1439 participants; moderate-certainty evidence).Xpert MTB/RIF pooled sensitivity was 98% (97% to 98%) in smear-positive and 67% (62% to 72%) in smear-negative, culture-positive participants, (45 studies). Xpert MTB/RIF pooled sensitivity was 88% (83% to 92%) in HIV-negative and 81% (75% to 86%) in HIV-positive participants; specificities were similar 98% (97% to 99%), (14 studies).Rifampicin resistance detectionXpert MTB/RIF pooled sensitivity and specificity (95% Crl) were 96% (94% to 97%) and 98% (98% to 99%), (48 studies, 8020 participants; high-certainty evidence).For a population of 1000 people where 100 have rifampicin-resistant tuberculosis, 114 would be positive for rifampicin-resistant tuberculosis and 18 (16%) would not have rifampicin resistance (false-positives); 886 would be would be negative for rifampicin-resistant tuberculosis and four (0.4%) would have rifampicin resistance (false-negatives).Xpert Ultra sensitivity (95% CI) was 95% (90% to 98%) versus Xpert MTB/RIF 95% (91% to 98%); Xpert Ultra specificity was 98% (97% to 99%) versus Xpert MTB/RIF 98% (96% to 99%), (1 study, 551 participants; moderate-certainty evidence). AUTHORS' CONCLUSIONS We found Xpert MTB/RIF to be sensitive and specific for diagnosing PTB and rifampicin resistance, consistent with findings reported previously. Xpert MTB/RIF was more sensitive for tuberculosis in smear-positive than smear-negative participants and HIV-negative than HIV-positive participants. Compared with Xpert MTB/RIF, Xpert Ultra had higher sensitivity and lower specificity for tuberculosis and similar sensitivity and specificity for rifampicin resistance (1 study). Xpert MTB/RIF and Xpert Ultra provide accurate results and can allow rapid initiation of treatment for multidrug-resistant tuberculosis.
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Affiliation(s)
- David J Horne
- University of WashingtonDepartment of Medicine, Division of Pulmonary and Critical Care Medicine, and Firland Northwest TB CenterSeattleUSA
| | - Mikashmi Kohli
- McGill UniversityDepartment of Epidemiology, Biostatistics and Occupational HealthMontrealCanada
| | - Jerry S Zifodya
- University of WashingtonPulmonary and Critical Care Medicine325 9th Avenue – Campus Box 359762SeattleUSA98104
| | - Ian Schiller
- McGill University Health Centre ‐ Research InstituteDivision of Clinical EpidemiologyMontrealCanada
| | - Nandini Dendukuri
- McGill University Health Centre ‐ Research InstituteDivision of Clinical EpidemiologyMontrealCanada
| | | | | | - Eleanor A Ochodo
- Stellenbosch UniversityCentre for Evidence‐based Health Care, Faculty of Medicine and Health SciencesPO Box 241Cape TownSouth Africa8000
| | - Madhukar Pai
- McGill UniversityDepartment of Epidemiology, Biostatistics and Occupational HealthMontrealCanada
| | - Karen R Steingart
- Department of Clinical Sciences, Liverpool School of Tropical MedicineHonorary Research FellowPembroke PlaceLiverpoolUK
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Piersimoni C, Gherardi G, Gracciotti N, Pocognoli A. Comparative evaluation of Xpert MTB/RIF and the new Xpert MTB/RIF ultra with respiratory and extra-pulmonary specimens for tuberculosis case detection in a low incidence setting. J Clin Tuberc Other Mycobact Dis 2019; 15:100094. [PMID: 31720421 PMCID: PMC6830143 DOI: 10.1016/j.jctube.2019.100094] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
BACKGROUND The Xpert MTB/RIF assay (Xpert) is an automated molecular test for the detection of tuberculosis and rifampin resistance (RIF-R), but it lacks sensitivity in smear-negative samples and some limitations in determination of RIF-R have also been reported. The new Xpert MTB/RIF Ultra (Ultra) was developed to overcome these limitations. We aimed to compare Ultra and Xpert diagnostic accuracy setting culture and drug susceptibility testing as reference standards. METHODS A retrospective analysis was performed on 359 consecutive, respiratory (269) and extrapulmonary (90) specimens collected from 340 patients investigated for TB along a two-year period. Patients presenting at primary health-care centres and hospitals were recruited on the basis of symptoms and abnormal X-ray imaging. One-hundred seventy-four subjects were identified to have active tuberculosis by culture and 2 were MDR. FINDINGS Sensitivities of Ultra and Xpert were 87% and 75% for the 48 individuals with smear-negative and culture-positive respiratory TB (difference of 12%, 95% CI 3 to 21); 95% and 72% for the 40 individuals with smear-negative and culture-positive extrapulmonary disease (22%, 95% CI 10 to 34); and 95% and 86%, respectively, across all 174 individuals with culture-positive samples (8.5%, 95% CI 4.5 to 12.5). Specificities of Ultra and Xpert for tuberculosis case detection were 98% and 100% (-2.0%, 95% CI -4.3 to +0.3). Ultra and Xpert performed equal in detecting RIF-R. INTERPRETATION Sensitivity of Ultra was superior to that of Xpert in all categories of clinical samples. However, improved sensitivity was associated with a modest reduction in specificity.
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Affiliation(s)
- Claudio Piersimoni
- Regional Reference Mycobacteriology Laboratory, Clinical Pathology Laboratory, United Hospitals, Ancona, Italy
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Sander MS, Laah SN, Titahong CN, Lele C, Kinge T, de Jong BC, Abena JLF, Codlin AJ, Creswell J. Systematic screening for tuberculosis among hospital outpatients in Cameroon: The role of screening and testing algorithms to improve case detection. J Clin Tuberc Other Mycobact Dis 2019; 15:100095. [PMID: 31720422 PMCID: PMC6830146 DOI: 10.1016/j.jctube.2019.100095] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Better screening and testing approaches are needed to improve TB case finding, particularly in health facilities where many people with TB seek care but are not diagnosed using the existing approaches. OBJECTIVE We aimed to evaluate the performance of various TB screening and testing approaches among hospital outpatients in a setting with a high prevalence of HIV/TB. METHODS We screened outpatients at a large hospital in Cameroon using both chest X-ray and a symptom questionnaire including current cough, fever, night sweats and/or weight loss. Participants with a positive screen were tested for TB using smear microscopy, the Xpert MTB/RIF assay, and culture. RESULTS Among 2051 people screened, 1137 (55%) reported one or more TB symptom and 389 (19%) had an abnormal chest X-ray. In total, 1255 people (61%) had a positive screen and 31 of those screened (1.5%) had bacteriologically confirmed TB. To detect TB, screening with cough >2 weeks had a sensitivity of 61% (95% CI, 44-78%). Screening for a combination of cough >2 -weeks and/or abnormal chest X-ray had a sensitivity of 81% (95% CI, 67-95%) and specificity of 71% (95% CI, 69-73%), while screening for a combination of cough >2 weeks or any of 2 or more symptoms had a similar performance. Smear microscopy and Xpert MTB/RIF detected 32% (10/31) and 55% (17/31), respectively, of people who had bacteriologically-confirmed TB. CONCLUSIONS Screening hospital outpatients for cough >2 weeks or for at least 2 of current cough, fever, night sweats or weight loss is a feasible strategy that had a high relative yield to detect bacteriologically-confirmed TB in this population. Clinical diagnosis of TB is still an important need, even where Xpert MTB/RIF testing is available.
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Affiliation(s)
- Melissa S. Sander
- Tuberculosis Reference Laboratory Bamenda, PO Box 586, Bamenda, Cameroon
| | | | | | | | | | - Bouke C. de Jong
- Institute of Tropical Medicine, Nationalestraat 155, 2000 Antwerp, Belgium
| | | | - Andrew J. Codlin
- Stop TB Partnership, Chemin du Pommier 40, 1218 Le Grand-Saconnex, Geneva, Switzerland
| | - Jacob Creswell
- Stop TB Partnership, Chemin du Pommier 40, 1218 Le Grand-Saconnex, Geneva, Switzerland
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Abstract
Introduction Early diagnosis and treatment of pulmonary tuberculosis (PTB) remains fundamental in reducing transmissions and death. Sputum induction is recommended for the diagnosis of pulmonary tuberculosis (PTB) in patients who are unable to expectorate or smear negative. Objective The aim of this study was to evaluate the diagnostic accuracy of pooling two induced sputum specimens into one microbiological test over a single day for the diagnosis of PTB. Methods We prospectively enrolled consecutive hospitalized adults with suspected PTB from 2009–2016. Two induced sputum specimens were obtained on the same day and pooled together for AFB smear, culture and Xpert MTB/RIF testing. The final diagnosis of PTB was based on a positive culture from any respiratory specimen. All patients were followed up for 3 months. Results Of 420 patients, 86(20.5%) were diagnosed with PTB based on a positive respiratory culture. The sensitivity, specificity, positive and negative predictive values for pooled induced sputum were 98.8% (CI 93.7–100%), 100% (CI 98.9–100%) and 100% (94.6–100%) and 99.7% (CI 98.1–100%) respectively. Xpert MTB/RIF in pooled induced sputum was positive in 88.4% of the PTB patients. Conclusion In the diagnosis of PTB, testing two induced sputum specimens which were pooled together for one microbiological testing process may be comparable to repeat testing.
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Affiliation(s)
- Mei Ying Chew
- Division of Respiratory and Critical Care Medicine, University Medicine Cluster, National University Hospital, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Corresponding author at: Division of Respiratory and Critical Care Medicine, National University Hospital, Level 10, Tower Block, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore.
| | - Jeffrey Ng
- Division of Respiratory and Critical Care Medicine, University Medicine Cluster, National University Hospital, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Tow Keang Lim
- Division of Respiratory and Critical Care Medicine, University Medicine Cluster, National University Hospital, Singapore
- Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Luo J, Zhang M, Yan B, Li F, Guan S, Chang K, Jiang W, Xu H, Yuan T, Chen M, Deng S. Diagnostic performance of plasma cytokine biosignature combination and MCP-1 as individual biomarkers for differentiating stages Mycobacterium tuberculosis infection. J Infect 2019; 78:281-291. [DOI: 10.1016/j.jinf.2018.10.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 10/27/2018] [Accepted: 10/29/2018] [Indexed: 12/20/2022]
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Madico G, Vinhas S, Orr B, White L, Gaeddert M, Miller NS, Mpeirwe M, Orikiriza P, Mwanga-Amumpaire J, Boum Y, Palaci M, Dietze R, Jones-López EC. Further evidence of Mycobacterium tuberculosis in the sputum of culture-negative pulmonary tuberculosis suspects using an ultrasensitive molecular assay. Tuberculosis (Edinb) 2019; 116:1-7. [PMID: 30983569 DOI: 10.1016/j.tube.2019.03.007] [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: 02/13/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Rapid diagnosis of pulmonary tuberculosis (TB) is critical to TB control. However, many patients with paucibacillary TB disease remain undiagnosed. Current TB elimination goals require new tools to diagnose early disease. We evaluated performance of the Totally Optimized PCR (TOP) TB assay, a novel ultrasensitive molecular test. METHODS We assessed analytical specificity against nontuberculous mycobacteria (NTM), and estimated the diagnostic accuracy of TOP in a pilot study in Brazil (n = 46) and a cross-sectional study in Boston (n = 60). We compared TOP results to culture and a composite reference standard (CRS). RESULTS TOP exhibited no cross-reactivity against NTM. We tested 132 respiratory specimens from 106 patients with suspected pulmonary TB. The pilot demonstrated feasibility and 100% (95% CI 85-100) sensitivity in predominantly smear-positive specimens; TOP's specificity against solid media culture was low (58%, 37-77) but improved against a CRS (93%, 68-100). Similarly, when using the CRS in the Boston study, TOP (88%, 1-99) had greater sensitivity than solid or liquid media culture (25%, 3-65) and similar specificity (both 100%, 93-100). CONCLUSIONS The TOP assay enables detection of M. tuberculosis in culture-negative paucibacillary disease. While the use of TOP for the diagnosis of paucibacillary disease will require further clinical validation, its high sensitivity indicate a more immediate utility as a rule out TB test.
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Affiliation(s)
- Guillermo Madico
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA, USA.
| | - Solange Vinhas
- Núcleo de Doenças Infecciosas, Universidade Federal do Espírito Santo, Vitória, Brazil.
| | - Beverley Orr
- Clinical Microbiology Laboratory, Boston Medical Center, Boston, MA, USA.
| | - Laura White
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA.
| | - Mary Gaeddert
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA, USA.
| | - Nancy S Miller
- Clinical Microbiology Laboratory, Boston Medical Center, Boston, MA, USA; Department of Pathology and Laboratory Medicine, Boston University School of Medicine, Boston, MA, USA.
| | - Moses Mpeirwe
- Mbarara University of Science and Technology, Mbarara, Uganda.
| | - Patrick Orikiriza
- Mbarara University of Science and Technology, Mbarara, Uganda; Epicentre, Médecins sans Frontières, Mbarara, Uganda.
| | | | - Yap Boum
- Mbarara University of Science and Technology, Mbarara, Uganda; Epicentre, Médecins sans Frontières, Mbarara, Uganda.
| | - Moises Palaci
- Núcleo de Doenças Infecciosas, Universidade Federal do Espírito Santo, Vitória, Brazil.
| | - Reynaldo Dietze
- Núcleo de Doenças Infecciosas, Universidade Federal do Espírito Santo, Vitória, Brazil.
| | - Edward C Jones-López
- Section of Infectious Diseases, Department of Medicine, Boston Medical Center and Boston University School of Medicine, Boston, MA, USA.
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Abstract
Of the 10 million incident cases of tuberculosis (TB) globally in 2017, around 558,000 cases were rifampicin-resistant of which 82% were multidrug-resistant (MDR) TB. In England, 5,102 cases were recorded of which 55 cases (1.8%) were MDR-TB. MDR-TB cases have worse outcomes and are a serious public health issue.Polymerase chain reaction (PCR) tests allow a faster approach to diagnose TB and predict drug susceptibility. The emerging use of whole genome sequencing may improve the diagnostic workflow compared with standard drug susceptibility testing, with more rapid molecular sensitivity results and more precise contact investigation of linked cases.Treatment of MDR-TB remains a challenge as it relies on prolonged second-line drug treatments that are less effective and more toxic than first-line treatments. Two new drug treatments have been approved; bedaquiline and delamanid. In addition, a shorter treatment regimen of 9-12 months can be considered instead of the conventional 20-24 month regimen.
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Affiliation(s)
- Mirae Park
- Department of Respiratory Medicine, Imperial College Healthcare NHS Trust, London, UK
| | | | - Onn Min Kon
- Department of Respiratory Medicine, Imperial College Healthcare NHS Trust, London, UK
- National Heart and Lung Institute, Imperial College London, London, UK
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Tuberculosis risk factors and Mycobacterium tuberculosis transmission among HIV-infected patients in Vietnam. Tuberculosis (Edinb) 2019; 115:67-75. [PMID: 30948179 DOI: 10.1016/j.tube.2019.02.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 12/18/2018] [Accepted: 02/03/2019] [Indexed: 01/28/2023]
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Hodille E, Maisson A, Charlet L, Bauduin C, Genestet C, Fredenucci I, Rasigade JP, Lina G, Dumitrescu O. Evaluation of Xpert MTB/RIF Ultra performance for pulmonary tuberculosis diagnosis on smear-negative respiratory samples in a French centre. Eur J Clin Microbiol Infect Dis 2019; 38:601-605. [DOI: 10.1007/s10096-018-03463-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 12/26/2018] [Indexed: 10/27/2022]
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Whitworth HS, Badhan A, Boakye AA, Takwoingi Y, Rees-Roberts M, Partlett C, Lambie H, Innes J, Cooke G, Lipman M, Conlon C, Macallan D, Chua F, Post FA, Wiselka M, Woltmann G, Deeks JJ, Kon OM, Lalvani A. Clinical utility of existing and second-generation interferon-γ release assays for diagnostic evaluation of tuberculosis: an observational cohort study. THE LANCET. INFECTIOUS DISEASES 2019; 19:193-202. [PMID: 30655049 DOI: 10.1016/s1473-3099(18)30613-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 09/20/2018] [Accepted: 10/03/2018] [Indexed: 01/03/2023]
Abstract
BACKGROUND The clinical utility of interferon-γ release assays (IGRAs) for diagnosis of active tuberculosis is unclear, although they are commonly used in countries with a low incidence of tuberculosis. We aimed to resolve this clinical uncertainty by determining the accuracy and utility of commercially available and second-generation IGRAs in the diagnostic assessment of suspected tuberculosis in a low-incidence setting. METHODS We did a prospective cohort study of adults with suspected tuberculosis in routine secondary care in England. Patients were tested for Mycobacterium tuberculosis infection at baseline with commercially available (T-SPOT.TB and QuantiFERON-TB Gold In-Tube [QFT-GIT]) and second-generation (incorporating novel M tuberculosis antigens) IGRAs and followed up for 6-12 months to establish definitive diagnoses. Sensitivity, specificity, positive and negative likelihood ratios, and predictive values of the tests were determined. FINDINGS Of the 1060 adults enrolled in the study, 845 were included in the analyses and 363 were diagnosed with tuberculosis. Sensitivity of T-SPOT.TB for all tuberculosis diagnosis, including culture-confirmed and highly probable cases, was 81·4% (95% CI 76·6-85·3), which was higher than QFT-GIT (67·3% [62·0-72·1]). Second-generation IGRAs had a sensitivity of 94·0% (90·0-96·4) for culture-confirmed tuberculosis and 89·2% (85·2-92·2) when including highly probable tuberculosis, giving a negative likelihood ratio for all tuberculosis cases of 0·13 (95% CI 0·10-0·19). Specificity ranged from 86·2% (95% CI 82·3-89·4) for T-SPOT.TB to 80·0% (75·6-83·8) for second-generation IGRAs. INTERPRETATION Commercially available IGRAs do not have sufficient accuracy for diagnostic evaluation of suspected tuberculosis. Second-generation tests, however, might have sufficiently high sensitivity, low negative likelihood ratio, and correspondingly high negative predictive value in low-incidence settings to facilitate prompt rule-out of tuberculosis. FUNDING National Institute for Health Research.
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Affiliation(s)
- Hilary S Whitworth
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK; Department of Clinical Research, London School of Hygiene and Tropical Medicine, London, UK
| | - Amarjit Badhan
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK; National Institute for Health Research Health Protection Research Unit in Respiratory Infections, Imperial College London, London, UK
| | - Aime A Boakye
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK; National Institute for Health Research Health Protection Research Unit in Respiratory Infections, Imperial College London, London, UK
| | - Yemisi Takwoingi
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK
| | - Melanie Rees-Roberts
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK; National Institute for Health Research Health Protection Research Unit in Respiratory Infections, Imperial College London, London, UK; Centre for Health Services Studies, University of Kent, Canterbury, UK
| | | | - Heather Lambie
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK
| | - John Innes
- Heart of England National Health Service (NHS) Foundation Trust, Birmingham, UK
| | - Graham Cooke
- Department of Infectious Diseases, St Mary's Hospital, Imperial College Healthcare Trust, London, UK
| | - Marc Lipman
- Department of Respiratory Medicine, Royal Free London NHS Foundation Trust, London, UK; University College London Respiratory, Division of Medicine, University College London, London, UK
| | - Christopher Conlon
- Nuffield Department of Medicine, Oxford University Hospitals NHS Trust, Oxford, UK
| | - Derek Macallan
- Infection Care Group, St George's University Hospitals NHS Foundation Trust, London, UK; Institute of Infection and Immunity, St George's, University of London, London, UK
| | - Felix Chua
- Department of Respiratory Medicine, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Frank A Post
- Department of Sexual Health and HIV, King's College Hospital NHS Foundation Trust, London, UK
| | - Martin Wiselka
- Department of Infection and Tropical Medicine, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Gerrit Woltmann
- Department of Infection, Immunity and Inflammation, Respiratory Biomedical Research Centre, Institute for Lung Health, University of Leicester, Leicester, UK
| | - Jonathan J Deeks
- Institute of Applied Health Research, University of Birmingham, Birmingham, UK
| | - Onn Min Kon
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK; National Institute for Health Research Health Protection Research Unit in Respiratory Infections, Imperial College London, London, UK
| | - Ajit Lalvani
- Tuberculosis Research Centre, National Heart and Lung Institute, Imperial College London, London, UK; National Institute for Health Research Health Protection Research Unit in Respiratory Infections, Imperial College London, London, UK.
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Metaferia Y, Seid A, Fenta GM, Gebretsadik D. Assessment of Extrapulmonary Tuberculosis Using Gene Xpert MTB/RIF Assay and Fluorescent Microscopy and Its Risk Factors at Dessie Referral Hospital, Northeast Ethiopia. BIOMED RESEARCH INTERNATIONAL 2018; 2018:8207098. [PMID: 30159328 PMCID: PMC6106971 DOI: 10.1155/2018/8207098] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 06/07/2018] [Accepted: 07/05/2018] [Indexed: 12/31/2022]
Abstract
BACKGROUND Tuberculosis is a major public health problem and extrapulmonary tuberculosis (EPTB) accounts for a significant proportion of tuberculosis cases worldwide. OBJECTIVE To determine the magnitude of EPTB, associated risk factors, and agreement of diagnostic techniques at Dessie Referral Hospital. METHODS A cross-sectional study was conducted on consecutive presumptive EPTB cases from March 1 to June 30, 2017. Sociodemographic characteristics and other variables were collected using a structured questionnaire. Clinical specimens were collected and processed using fluorescent microscopy and Gene Xpert assay. Data was analyzed using SPSS version 20. Chi-square test and logistic regression were done and a P value of ≤0.05 was taken as statistically significant. RESULTS From a total of 353 presumptive EPTB cases the overall prevalence of Gene Xpert assay and smear confirmed patients was 8.8% and 2.5%, respectively. Tuberculosis lymphadenitis was the predominant (33.3%) type followed by pleural (11.9%) and peritoneal (6.7%) tuberculosis. Previous history of pulmonary tuberculosis was significantly associated with extrapulmonary infection (AOR:2.8; 95%CI: 1.05-7.54; p=0.04); however, other variables such as age, residence, sex, marital status, occupation, level of education, and monthly income did not show any association. CONCLUSION High proportions (71%) of Gene Xpert assay confirmed EPTB patients were smear-negative. Sensitivity of microscopy should be enhanced in resource limited countries like Ethiopia where Gene Xpert machine is not easily accessible.
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Affiliation(s)
- Yeshi Metaferia
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Wollo University, Ethiopia
| | - Abdurahaman Seid
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Wollo University, Ethiopia
| | - Genet Mola Fenta
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Wollo University, Ethiopia
| | - Daniel Gebretsadik
- Department of Medical Laboratory Science, College of Medicine and Health Sciences, Wollo University, Ethiopia
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Incipient and Subclinical Tuberculosis: a Clinical Review of Early Stages and Progression of Infection. Clin Microbiol Rev 2018; 31:31/4/e00021-18. [PMID: 30021818 DOI: 10.1128/cmr.00021-18] [Citation(s) in RCA: 303] [Impact Index Per Article: 50.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tuberculosis (TB) is the leading infectious cause of mortality worldwide, due in part to a limited understanding of its clinical pathogenic spectrum of infection and disease. Historically, scientific research, diagnostic testing, and drug treatment have focused on addressing one of two disease states: latent TB infection or active TB disease. Recent research has clearly demonstrated that human TB infection, from latent infection to active disease, exists within a continuous spectrum of metabolic bacterial activity and antagonistic immunological responses. This revised understanding leads us to propose two additional clinical states: incipient and subclinical TB. The recognition of incipient and subclinical TB, which helps divide latent and active TB along the clinical disease spectrum, provides opportunities for the development of diagnostic and therapeutic interventions to prevent progression to active TB disease and transmission of TB bacilli. In this report, we review the current understanding of the pathogenesis, immunology, clinical epidemiology, diagnosis, treatment, and prevention of both incipient and subclinical TB, two emerging clinical states of an ancient bacterium.
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Baron EJ, Tenover FC, Gnanashanmugam D. Direct Detection of Mycobacterium tuberculosis in Clinical Specimens Using Nucleic Acid Amplification Tests. ACTA ACUST UNITED AC 2018. [DOI: 10.1016/j.clinmicnews.2018.06.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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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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Sulis G, Agliati A, Pinsi G, Bozzola G, Foccoli P, Gulletta M, Caligaris S, Tomasoni LR, El-Hamad I, Matteelli A. Xpert MTB/RIF as add-on test to microscopy in a low tuberculosis incidence setting. Eur Respir J 2018; 51:13993003.02345-2017. [DOI: 10.1183/13993003.02345-2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 01/10/2018] [Indexed: 11/05/2022]
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Dorman SE, Schumacher SG, Alland D, Nabeta P, Armstrong DT, King B, Hall SL, Chakravorty S, Cirillo DM, Tukvadze N, Bablishvili N, Stevens W, Scott L, Rodrigues C, Kazi MI, Joloba M, Nakiyingi L, Nicol MP, Ghebrekristos Y, Anyango I, Murithi W, Dietze R, Lyrio Peres R, Skrahina A, Auchynka V, Chopra KK, Hanif M, Liu X, Yuan X, Boehme CC, Ellner JJ, Denkinger CM. Xpert MTB/RIF Ultra for detection of Mycobacterium tuberculosis and rifampicin resistance: a prospective multicentre diagnostic accuracy study. THE LANCET. INFECTIOUS DISEASES 2018; 18:76-84. [PMID: 29198911 PMCID: PMC6168783 DOI: 10.1016/s1473-3099(17)30691-6] [Citation(s) in RCA: 435] [Impact Index Per Article: 72.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 10/04/2017] [Accepted: 10/20/2017] [Indexed: 12/24/2022]
Abstract
BACKGROUND The Xpert MTB/RIF assay is an automated molecular test that has improved the detection of tuberculosis and rifampicin resistance, but its sensitivity is inadequate in patients with paucibacillary disease or HIV. Xpert MTB/RIF Ultra (Xpert Ultra) was developed to overcome this limitation. We compared the diagnostic performance of Xpert Ultra with that of Xpert for detection of tuberculosis and rifampicin resistance. METHODS In this prospective, multicentre, diagnostic accuracy study, we recruited adults with pulmonary tuberculosis symptoms presenting at primary health-care centres and hospitals in eight countries (South Africa, Uganda, Kenya, India, China, Georgia, Belarus, and Brazil). Participants were allocated to the case detection group if no drugs had been taken for tuberculosis in the past 6 months or to the multidrug-resistance risk group if drugs for tuberculosis had been taken in the past 6 months, but drug resistance was suspected. Demographic information, medical history, chest imaging results, and HIV test results were recorded at enrolment, and each participant gave at least three sputum specimen on 2 separate days. Xpert and Xpert Ultra diagnostic performance in the same sputum specimen was compared with culture tests and drug susceptibility testing as reference standards. The primary objectives were to estimate and compare the sensitivity of Xpert Ultra test with that of Xpert for detection of smear-negative tuberculosis and rifampicin resistance and to estimate and compare Xpert Ultra and Xpert specificities for detection of rifampicin resistance. Study participants in the case detection group were included in all analyses, whereas participants in the multidrug-resistance risk group were only included in analyses of rifampicin-resistance detection. FINDINGS Between Feb 18, and Dec 24, 2016, we enrolled 2368 participants for sputum sampling. 248 participants were excluded from the analysis, and 1753 participants were distributed to the case detection group (n=1439) and the multidrug-resistance risk group (n=314). Sensitivities of Xpert Ultra and Xpert were 63% and 46%, respectively, for the 137 participants with smear-negative and culture-positive sputum (difference of 17%, 95% CI 10 to 24); 90% and 77%, respectively, for the 115 HIV-positive participants with culture-positive sputum (13%, 6·4 to 21); and 88% and 83%, respectively, across all 462 participants with culture-positive sputum (5·4%, 3·3 to 8·0). Specificities of Xpert Ultra and Xpert for case detection were 96% and 98% (-2·7%, -3·9 to -1·7) overall, and 93% and 98% for patients with a history of tuberculosis. Xpert Ultra and Xpert performed similarly in detecting rifampicin resistance. INTERPRETATION For tuberculosis case detection, sensitivity of Xpert Ultra was superior to that of Xpert in patients with paucibacillary disease and in patients with HIV. However, this increase in sensitivity came at the expense of a decrease in specificity. FUNDING Government of Netherlands, Government of Australia, Bill & Melinda Gates Foundation, Government of the UK, and the National Institute of Allergy and Infectious Diseases.
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Affiliation(s)
- Susan E Dorman
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - David Alland
- Division of Infectious Diseases, Rutgers-New Jersey Medical School, Newark, NJ, USA
| | | | | | - Bonnie King
- Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sandra L Hall
- Boston Medical Center and Boston University School of Medicine, Boston, MA, USA
| | | | | | - Nestani Tukvadze
- National Center for Tuberculosis and Lung Diseases, Tbilisi, Georgia
| | - Nino Bablishvili
- National Center for Tuberculosis and Lung Diseases, Tbilisi, Georgia
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, Faculty of Health Science, School of Pathology and the National Priority Program of the National Health Laboratory Service, Johannesburg, South Africa
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, Faculty of Health Science, School of Pathology and the National Priority Program of the National Health Laboratory Service, Johannesburg, South Africa
| | | | - Mubin I Kazi
- PD Hinduja Hospital and Medical Research Centre, Mumbai, India
| | - Moses Joloba
- Mycobacteriology Laboratory, Department of Microbiology, School of Biomedical Sciences, Makerere University, Kampala, Uganda
| | - Lydia Nakiyingi
- Infectious Disease Institute, Makerere University, Kampala, Uganda
| | - Mark P Nicol
- Division of Medical Microbiology and Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa; National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa
| | - Yonas Ghebrekristos
- Division of Medical Microbiology and Institute for Infectious Diseases and Molecular Medicine, University of Cape Town, Cape Town, South Africa; National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa
| | - Irene Anyango
- Kenya Medical Research Institute, Center for Global Health Research, Kisumu, Kenya
| | - Wilfred Murithi
- Kenya Medical Research Institute, Center for Global Health Research, Kisumu, Kenya
| | | | | | - Alena Skrahina
- National Reference Laboratory, Republican Scientific and Practical Centre for Pulmonology and Tuberculosis, Minsk, Belarus
| | - Vera Auchynka
- National Reference Laboratory, Republican Scientific and Practical Centre for Pulmonology and Tuberculosis, Minsk, Belarus
| | | | - Mahmud Hanif
- State TB Training & Demonstration Centre, New Delhi, India
| | - Xin Liu
- Henan Provincial Chest Hospital, Zhengzhou, Henan Province, China
| | - Xing Yuan
- Henan Provincial Chest Hospital, Zhengzhou, Henan Province, China
| | | | - Jerrold J Ellner
- Boston Medical Center and Boston University School of Medicine, Boston, MA, USA
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Rice JP, Seifert M, Moser KS, Rodwell TC. Performance of the Xpert MTB/RIF assay for the diagnosis of pulmonary tuberculosis and rifampin resistance in a low-incidence, high-resource setting. PLoS One 2017; 12:e0186139. [PMID: 29016684 PMCID: PMC5633176 DOI: 10.1371/journal.pone.0186139] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Accepted: 09/26/2017] [Indexed: 02/07/2023] Open
Abstract
Performance of the Xpert MTB/RIF assay, designed to simultaneously detect Mycobacterium tuberculosis complex (MTBC) and rifampin (RIF) resistance, has been well documented in low-resource settings with high TB-incidence. However, few studies have assessed its accuracy in low TB incidence settings. We evaluated the performance of Xpert MTB/RIF using clinical sputum specimens routinely collected from suspect pulmonary TB patients over a 4-year time period in San Diego County, California. Xpert MTB/RIF results were compared to acid-fast bacilli (AFB) smear microscopy, mycobacterial culture, and phenotypic drug susceptibility testing (DST). Of 751 sputum specimens, 134 (17.8%) were MTBC culture-positive and 2 (1.5%) were multidrug-resistant (MDR). For the detection of MTBC, Xpert MTB/RIF sensitivity was 89.6% (97.7% and 74.5% in smear-positive and -negative sputa, respectively) and specificity was 97.2%; while AFB smear sensitivity and specificity were 64.9% and 77.8%, respectively. Xpert MTB/RIF detected 35 of 47 smear-negative culture-positive specimens, and excluded 124 of 137 smear-positive culture-negative specimens. Xpert MTB/RIF also correctly excluded 99.2% (121/122) of nontuberculous mycobacteria (NTM) specimens, including all 33 NTM false-positives by smear microscopy. For the detection of RIF resistance, Xpert MTB/RIF sensitivity and specificity were 100% and 98.3%, respectively. Our findings demonstrate that Xpert MTB/RIF is able to accurately detect MTBC and RIF resistance in routinely collected respiratory specimens in a low TB-incidence setting, with comparable performance to that achieved in high-incidence settings; and suggest that under these conditions the assay has particular utility in detecting smear-negative TB cases, excluding smear-positive patients without MTBC disease, and differentiating MTBC from NTM.
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Affiliation(s)
- Jason P. Rice
- Division of Preventive Medicine, University of California, San Diego, California, United States of America
- * E-mail:
| | - Marva Seifert
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California, United States of America
| | - Kathleen S. Moser
- Tuberculosis Control and Refugee Health Program, County of San Diego Health and Human Services Agency, San Diego, California, United States of America
| | - Timothy C. Rodwell
- Division of Pulmonary, Critical Care and Sleep Medicine, University of California, San Diego, California, United States of America
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The New Xpert MTB/RIF Ultra: Improving Detection of Mycobacterium tuberculosis and Resistance to Rifampin in an Assay Suitable for Point-of-Care Testing. mBio 2017; 8:mBio.00812-17. [PMID: 28851844 PMCID: PMC5574709 DOI: 10.1128/mbio.00812-17] [Citation(s) in RCA: 398] [Impact Index Per Article: 56.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The Xpert MTB/RIF assay (Xpert) is a rapid test for tuberculosis (TB) and rifampin resistance (RIF-R) suitable for point-of-care testing. However, it has decreased sensitivity in smear-negative sputum, and false identification of RIF-R occasionally occurs. We developed the Xpert MTB/RIF Ultra assay (Ultra) to improve performance. Ultra and Xpert limits of detection (LOD), dynamic ranges, and RIF-R rpoB mutation detection were tested on Mycobacterium tuberculosis DNA or sputum samples spiked with known numbers of M. tuberculosis H37Rv or Mycobacterium bovis BCG CFU. Frozen and prospectively collected clinical samples from patients suspected of having TB, with and without culture-confirmed TB, were also tested. For M. tuberculosis H37Rv, the LOD was 15.6 CFU/ml of sputum for Ultra versus 112.6 CFU/ml of sputum for Xpert, and for M. bovis BCG, it was 143.4 CFU/ml of sputum for Ultra versus 344 CFU/ml of sputum for Xpert. Ultra resulted in no false-positive RIF-R specimens, while Xpert resulted in two false-positive RIF-R specimens. All RIF-R-associated M. tuberculosis rpoB mutations tested were identified by Ultra. Testing on clinical sputum samples, Ultra versus Xpert, resulted in an overall sensitivity of 87.5% (95% confidence interval [CI], 82.1, 91.7) versus 81.0% (95% CI, 74.9, 86.2) and a sensitivity on sputum smear-negative samples of 78.9% (95% CI, 70.0, 86.1) versus 66.1% (95% CI, 56.4, 74.9). Both tests had a specificity of 98.7% (95% CI, 93.0, 100), and both had comparable accuracies for detection of RIF-R in these samples. Ultra should significantly improve TB detection, especially in patients with paucibacillary disease, and may provide more-reliable RIF-R detection. The Xpert MTB/RIF assay (Xpert), the first point-of-care assay for tuberculosis (TB), was endorsed by the World Health Organization in December 2010. Since then, 23 million Xpert tests have been procured in 130 countries. Although Xpert showed high overall sensitivity and specificity with pulmonary samples, its sensitivity has been lower with smear-negative pulmonary samples and extrapulmonary samples. In addition, the prediction of rifampin resistance (RIF-R) in paucibacillary samples and for a few rpoB mutations has resulted in both false-positive and false-negative results. The present study is the first demonstration of the design features and operational characteristics of an improved Xpert Ultra assay. This study also shows that the Ultra format overcomes many of the known shortcomings of Xpert. The new assay should significantly improve TB detection, especially in patients with paucibacillary disease, and provide more-reliable detection of RIF-R.
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Three year evaluation of Xpert MTB/RIF in a low prevalence tuberculosis setting: A Scottish perspective. J Infect 2017; 74:466-472. [DOI: 10.1016/j.jinf.2017.02.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 01/13/2017] [Accepted: 02/10/2017] [Indexed: 11/18/2022]
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Lombardi G, Di Gregori V, Girometti N, Tadolini M, Bisognin F, Dal Monte P. Diagnosis of smear-negative tuberculosis is greatly improved by Xpert MTB/RIF. PLoS One 2017; 12:e0176186. [PMID: 28430807 PMCID: PMC5400262 DOI: 10.1371/journal.pone.0176186] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 04/06/2017] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Diagnosis of pulmonary (PTB) and extra-pulmonary tuberculosis (EPTB) in smear-negative patients can be difficult. We assessed retrospectively the performance of Xpert MTB/RIF system (Xpert, Cepheid) in diagnosing smear-negative tuberculosis (TB), which represents the most common form of TB in a low incidence setting. METHODS Performance of Xpert was compared to acid-fast microscopic examination using Ziehl-Neelsen (ZN) stain in patients with culture-confirmed TB. RESULTS 386 Mycobacterium tuberculosis (MTB) culture-positive samples were detected out of 5170 specimens tested with smear microscopy, Xpert and culture: 323 were both culture- and Xpert-positive, and 63 culture-positive only. Of these, 234 (60.6%) were smear-negative. In addition Xpert detected 40 probable TB cases, based on clinical findings, which were culture-negative. Compared to culture, Xpert showed an overall sensitivity of 83.7% and a specificity of 99.1%; sensitivity was higher for respiratory samples (86.5%) than for non-respiratory samples (76.8%). Xpert sensitivity for smear-negative culture-confirmed TB was 73.1% and was not influenced by TB localization. As sensitivity of microscopy alone was poor (39.4%), Xpert improved both diagnosis of pulmonary TB (Δ = 36.5%) and extra-pulmonary TB (Δ = 63.4%). CONCLUSIONS Xpert MTB/RIF is a sensitive method for rapid diagnosis of TB compared to the conventional ZN staining. Xpert can serve as a sensitive and time-saving diagnostic method for microbiological diagnosis of smear-negative TB in countries with a low TB prevalence.
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Affiliation(s)
- Giulia Lombardi
- Department of Experimental, Diagnostic and Specialty Medicine - Unit of Microbiology, Alma Mater Studiorum University of Bologna - S. Orsola-Malpighi University Hospital, Bologna, Italy
- * E-mail:
| | - Valentina Di Gregori
- Department of Biomedical and Neuromotor Sciences, Section of Hygiene and Public Health, Alma Mater Studiorum University of Bologna, Bologna, Italy
| | - Nicolò Girometti
- Department of Medical and Surgical Sciences - Unit of Infectious Diseases, Alma Mater Studiorum University of Bologna - S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Marina Tadolini
- Department of Medical and Surgical Sciences - Unit of Infectious Diseases, Alma Mater Studiorum University of Bologna - S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Francesco Bisognin
- Department of Experimental, Diagnostic and Specialty Medicine - Unit of Microbiology, Alma Mater Studiorum University of Bologna - S. Orsola-Malpighi University Hospital, Bologna, Italy
| | - Paola Dal Monte
- Department of Experimental, Diagnostic and Specialty Medicine - Unit of Microbiology, Alma Mater Studiorum University of Bologna - S. Orsola-Malpighi University Hospital, Bologna, Italy
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Cowan JF, Chandler AS, Kracen E, Park DR, Wallis CK, Liu E, Song C, Persing DH, Fang FC. Clinical Impact and Cost-effectiveness of Xpert MTB/RIF Testing in Hospitalized Patients With Presumptive Pulmonary Tuberculosis in the United States. Clin Infect Dis 2017; 64:482-489. [PMID: 28172666 PMCID: PMC5399932 DOI: 10.1093/cid/ciw803] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 12/01/2016] [Indexed: 11/12/2022] Open
Abstract
Background Microscopic examination of acid-fast-stained sputum smears is the current standard of care in the United States to determine airborne infection isolation (AII) of inpatients with presumptive pulmonary tuberculosis (PTB). However, nucleic acid amplification testing (NAAT) with the Xpert MTB/RIF assay (Xpert) may be more efficient and less costly. Methods This prospective observational cohort study enrolled a consecutive sample of 318 AII-eligible inpatients from a public hospital in Seattle, Washington, from March 2012 to October 2013. Sputum samples were collected from each inpatient and analyzed using smear microscopy, culture, drug susceptibility testing, and NAAT. The performance, clinical utility (AII duration and survival), and cost-effectiveness from an institutional perspective were compared for 5 testing strategies. Results Among the 318 admissions with presumptive PTB, 20 (6.3%) were culture-positive for Mycobacterium tuberculosis. The sensitivity of 1 Xpert, 2 Xperts, 2 smears, or 3 smears compared to culture was 0.85 (95% confidence interval [CI], .61–.96), 0.95 (95% CI, .73–1.0), 0.70 (95% CI, .46–.88), and 0.80 (95% CI, .56–.93), respectively. A cost-effectiveness analysis of the study results demonstrated that an Xpert test on 1 unconcentrated sputum sample (assuming equivalent results for unconcentrated and concentrated sputum samples) is the most cost-effective strategy (99.9% preferred at willingness-to-pay of US$50000) and on average would save 51.5 patient-hours in AII and up to $11466 relative to microscopy without a compromise in sensitivity. Conclusions In hospitalized patients with presumptive PTB in a low-burden setting, NAAT can reduce AII and is comparably sensitive, more specific, and more cost-effective than smear microscopy.
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Affiliation(s)
- James F Cowan
- Department of Global Health, University of Washington Schools of Medicine and Public Health
| | | | - Elizabeth Kracen
- Department of Medicine, University of Washington School of Medicine
| | - David R Park
- Department of Global Health, University of Washington Schools of Medicine and Public Health
- Harborview Medical Center
| | - Carolyn K Wallis
- Harborview Medical Center
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle
| | | | | | | | - Ferric C Fang
- Harborview Medical Center
- Department of Laboratory Medicine, University of Washington School of Medicine, Seattle
- Department of Microbiology, University of Washington School of Medicine, Seattle
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Stevens WS, Scott L, Noble L, Gous N, Dheda K. Impact of the GeneXpert MTB/RIF Technology on Tuberculosis Control. Microbiol Spectr 2017; 5. [PMID: 28155817 DOI: 10.1128/microbiolspec.tbtb2-0040-2016] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Indexed: 11/20/2022] Open
Abstract
Molecular technology revolutionized the diagnosis of tuberculosis (TB) with a paradigm shift to faster, more sensitive, clinically relevant patient care. The most recent molecular leader is the GeneXpert MTB/RIF assay (Xpert) (Cepheid, Sunnyvale, CA), which was endorsed by the World Health Organization with unprecedented speed in December 2010 as the initial diagnostic for detection of HIV-associated TB and for where high rates of drug resistance are suspected. South Africa elected to take an aggressive smear replacement approach to facilitate earlier diagnosis and treatment through the decision to implement the Xpert assay nationally in March 2011, against the backdrop of approximately 6.3 million HIV-infected individuals, one of highest global TB and HIV coinfection rates, no available implementation models, uncertainties around field performance and program costs, and lack of guidance on how to operationalize the assay into existing complex clinical algorithms. South Africa's national implementation was conducted as a phased, forecasted, and managed approach (March 2011 to September 2013), through political will and both treasury-funded and donor-funded support. Today there are 314 GeneXperts across 207 microscopy centers; over 8 million assays have been conducted, and South Africa accounts for over half the global test cartridge usage. As with any implementation of new technology, challenges were encountered, both predicted and unexpected. This chapter discusses the challenges and consequences of such large-scale implementation efforts, the opportunities for new innovations, and the need to strengthen health systems, as well as the impact of the Xpert assay on rifampin-sensitive and multidrug-resistant TB patient care that translated into global TB control as we move toward the sustainable development goals.
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Affiliation(s)
- Wendy Susan Stevens
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, and National Health Laboratory Service and National Priority Program of the National Health Laboratory Service, Johannesburg, South Africa
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Lara Noble
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Gauteng, South Africa
| | - Natasha Gous
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, University of the Witwatersrand, and National Health Laboratory Service and National Priority Program of the National Health Laboratory Service, Johannesburg, South Africa
| | - Keertan Dheda
- Lung Infection and Immunity Unit, Division of Pulmonology and UCT Lung Institute, Department of Medicine, University of Cape Town, Cape Town, South Africa
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Dharan NJ, Blakemore R, Sloutsky A, Kaur D, Alexander RC, Ghajar M, Musser KA, Escuyer VE, Rowlinson MC, Crowe S, Laniado-Laborin R, Valli E, Nabeta P, Johnson P, Alland D. Performance of the G4 Xpert ® MTB/RIF assay for the detection of Mycobacterium tuberculosis and rifampin resistance: a retrospective case-control study of analytical and clinical samples from high- and low-tuberculosis prevalence settings. BMC Infect Dis 2016; 16:764. [PMID: 27993132 PMCID: PMC5168809 DOI: 10.1186/s12879-016-2039-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 11/15/2016] [Indexed: 11/10/2022] Open
Abstract
Background The Xpert® MTB/RIF (Xpert) assay is a rapid PCR-based assay for the detection of Mycobacterium tuberculosis complex DNA (MTBc) and mutations associated with rifampin resistance (RIF). An updated version introduced in 2011, the G4 Xpert, included modifications to probe B and updated analytic software. Methods An analytical study was performed to assess Xpert detection of mutations associated with rifampin resistance in rifampin-susceptible and -resistant isolates. A clinical study was performed in which specimens from US and non-US persons suspected of tuberculosis (TB) were tested to determine Xpert performance characteristics. All specimens underwent smear microscopy, mycobacterial culture, conventional drug-susceptibility testing and Xpert testing; DNA from isolates with discordant rifampin resistance results was sequenced. Results Among 191 laboratory-prepared isolates in the analytical study, Xpert sensitivity for detection of rifampin resistance associated mutations was 97.7% and specificity was 90.8%, which increased to 99.0% after DNA sequencing analysis of the discordant samples. Of the 1,096 subjects in the four clinical studies, 49% were from the US. Overall, Xpert detected MTBc in 439 of 468 culture-positive specimens for a sensitivity of 93.8% (95% confidence interval [CI]: 91.2%–95.7%) and did not detect MTBc in 620 of 628 culture-negative specimens for a specificity of 98.7% (95% CI: 97.5%–99.4%). Sensitivity was 99.7% among smear-positive cases, and 76.1% among smear-negative cases. Non-determinate MTBc detection and false-positive RIF resistance results were low (1.2 and 0.9%, respectively). Conclusions The updated Xpert assay retained the high sensitivity and specificity of the previous assay versions and demonstrated low rates of non-determinate and RIF resistance false positive results. Electronic supplementary material The online version of this article (doi:10.1186/s12879-016-2039-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Nila J Dharan
- Department of Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, MSB I-689, Newark, NJ, 07103, USA.
| | - Robert Blakemore
- Department of Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, MSB I-689, Newark, NJ, 07103, USA.,Current address: Sackler School of Graduate Biomedical Science - Tufts University, Boston, MA, USA
| | - Alex Sloutsky
- University of Massachusetts Medical School, Worcester, MA, USA
| | - Devinder Kaur
- University of Massachusetts Medical School, Worcester, MA, USA
| | | | - Minoo Ghajar
- Orange County Health Care Agency, Santa Ana, CA, USA
| | | | - Vincent E Escuyer
- Wadsworth Center, New York State Department of Health, Albany, NY, USA
| | | | | | | | - Eloise Valli
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | - Pamela Nabeta
- Foundation for Innovative New Diagnostics, Geneva, Switzerland
| | | | - David Alland
- Department of Medicine, New Jersey Medical School, Rutgers, The State University of New Jersey, 185 South Orange Avenue, MSB I-689, Newark, NJ, 07103, USA.
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Peralta G, Barry P, Pascopella L. Use of Nucleic Acid Amplification Tests in Tuberculosis Patients in California, 2010-2013. Open Forum Infect Dis 2016; 3:ofw230. [PMID: 27957506 PMCID: PMC5146759 DOI: 10.1093/ofid/ofw230] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 10/28/2016] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Nucleic acid amplification tests (NAATs) have been used as a diagnostic tool for tuberculosis (TB) in the United States for many years. We sought to assess NAAT use in TB patients in California during a period of time when NAAT availability increased throughout the world. METHODS We conducted a retrospective review of surveillance data from 6051 patients with culture-confirmed pulmonary TB who were reported to the California TB registry during 2010-2013. RESULTS Only 2336 of 6051 (39%) TB patients had a NAAT for diagnosis before culture results. Although 90% (N = 2101) with NAAT had positive test results, 9% (N = 217) had falsely negative NAAT results, and 0.8% (N = 18) had indeterminate NAAT results. The median time from specimen collection to TB treatment initiation was shorter when NAAT was used (3 vs 14 days, P < .0001), and patients with a positive NAAT result initiated treatment earlier than patients with a falsely negative result (1 vs 11 days from NAAT report, P < .0001). We confirmed the increased sensitivity of NAAT compared with acid-fast bacilli (AFB) smear microscopy in our study population; 92 of 145 AFB smear-negative patients had positive NAATs. Median time from specimen collection to NAAT result report differed by health jurisdiction, from 1 to 11 working days. CONCLUSIONS Increased use of NAATs in diagnosis of pulmonary TB could decrease the time-to-treatment initiation and consequently decrease transmission. However, differential use and access to NAAT may prevent full realization of NAAT benefits in California.
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Affiliation(s)
- Gianna Peralta
- Present Affiliation: Acute Disease Epidemiology Section, Georgia Department of Public Health , Georgia
| | - Pennan Barry
- Tuberculosis Control Branch, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health , Richmond
| | - Lisa Pascopella
- Tuberculosis Control Branch, Division of Communicable Disease Control, Center for Infectious Diseases, California Department of Public Health , Richmond
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Tsuyuguchi K, Nagai H, Ogawa K, Matsumoto T, Morimoto K, Takaki A, Mitarai S. Performance evaluation of Xpert MTB/RIF in a moderate tuberculosis incidence compared with TaqMan MTB and TRCRapid M.TB. J Infect Chemother 2016; 23:101-106. [PMID: 27919693 DOI: 10.1016/j.jiac.2016.11.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/07/2016] [Accepted: 11/08/2016] [Indexed: 10/20/2022]
Abstract
Xpert MTB/RIF is an automated nucleic acid amplification test (NAT) that can detect the presence of Mycobacterium tuberculosis complex (MTC) in clinical specimens as well as rifampicin (RIF) resistance resulting from rpoB mutation. Despite its high sensitivity and specificity for diagnosing tuberculosis (TB) with or without RIF resistance, the clinical performance of the test is variable. In this study, we evaluated the performance of Xpert MTB/RIF in a setting of moderate TB burden and high medical resources. A total of 427 sputum specimens were obtained from 237 suspected TB cases. Of these, 159 were identified as active TB, while the other 78 were non-TB diseases. The overall sensitivity and specificity of MTC detection by Xpert MTB/RIF using culture results as a reference were 86.8% [95% confidence interval (CI): 81.8%-90.6%] and 96.8% (95% CI: 93.1%-98.5%), respectively. Among MTC-positive culture specimens, Xpert MTB/RIF positivity was 95.2% (95% CI: 91.2%-97.5%) in smear-positive and 44.7% (95% CI 30.1-60.3) in smear-negative specimens. Xpert MTB/RIF was similar to other NATs (TaqMan MTB and TRCRapid M.TB) in terms of performance. Xpert MTB/RIF detected 25 RIF-resistant isolates as compared to 22 with the mycobacterial growth indicator tube antimicrobial susceptibility testing system, yielding a sensitivity of 100% (95% CI: 85.1%-100%) and specificity of 98.3% (95% CI: 95.1%-99.4%). These results indicate that although sensitivity in smear-negative/culture-positive specimens was relatively low, Xpert MTB/RIF is a useful diagnostic tool for detecting TB and RIF resistance even in settings of moderate TB burden.
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Affiliation(s)
- Kazunari Tsuyuguchi
- Clinical Research Center, Kinki-Chuo Chest Medical Center, National Hospital Organization, Japan
| | - Hideaki Nagai
- Center for Pulmonary Diseases, Tokyo National Hospital, National Hospital Organization, Japan
| | - Kenji Ogawa
- Department of Respiratory Medicine, Higashi Nagoya National Hospital, National Hospital Organization, Japan
| | - Tomoshige Matsumoto
- Osaka Prefectural Medical Center for Respiratory and Allergic Diseases, Osaka Prefectural Hospital Organization, Japan
| | - Kozo Morimoto
- Fukujuji Hospital, Japan Anti-Tuberculosis Association, Japan
| | - Akiko Takaki
- Department of Mycobacterium Reference and Research, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Japan
| | - Satoshi Mitarai
- Department of Mycobacterium Reference and Research, Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association, Japan; Department of Basic Mycobacteriology, Graduate School of Biomedical Sciences, Nagasaki University, Japan.
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Abstract
Multidrug-resistant tuberculosis (MDR TB) is a significant threat to global health estimated to account for nearly half a million new cases and over 200,000 deaths in 2013. The number of MDR TB cases in the UK has risen over the last 15 years, with ever more complex clinical cases and associated challenging public health and societal implications. In this review, we provide an overview of the epidemiology of MDR TB globally and in the UK, outline the clinical management of MDR TB and summarise recent advances in diagnostics and prospects for new treatment.
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Affiliation(s)
- Kartik Kumar
- Centre for Infectious Disease Epidemiology, Research Department of Infection and Population Health, University College London, London, UK, and The Whittington Hospital NHS Trust, Whittington Health, London, UK
| | - Ibrahim Abubakar
- Centre for Infectious Disease Epidemiology, University College London, London, UK, and MRC Clinical Trials Unit, University College London, London, UK
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Oxlade O, Sugarman J, Alvarez GG, Pai M, Schwartzman K. Xpert®MTB/RIF for the Diagnosis of Tuberculosis in a Remote Arctic Setting: Impact on Cost and Time to Treatment Initiation. PLoS One 2016; 11:e0150119. [PMID: 26990299 PMCID: PMC4798714 DOI: 10.1371/journal.pone.0150119] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2015] [Accepted: 02/09/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Tuberculosis (TB) remains a significant health problem in the Canadian Arctic. Substantial health system delays in TB diagnosis can occur, in part due to the lack of capacity for onsite microbiologic testing. A study recently evaluated the yield and impact of a rapid automated PCR test (Xpert®MTB/RIF) for the diagnosis of TB in Iqaluit (Nunavut). We conducted an economic analysis to evaluate the expected cost relative to the expected reduction in time to treatment initiation, with the addition of Xpert®MTB/RIF to the current diagnostic and treatment algorithms used in this setting. METHODS A decision analysis model compared current microbiologic testing to a scenario where Xpert®MTB/RIF was added to the current diagnostic algorithm for active TB, and incorporated costs and clinical endpoints from the Iqaluit study. Several sensitivity analyses that considered alternative use were also considered. We estimated days to TB diagnosis and treatment initiation, health system costs, and the incremental cost per treatment day gained for each individual evaluated for possible TB. RESULTS With the addition of Xpert®MTB/RIF, costs increased while days to TB treatment initiation were reduced. The incremental cost per treatment day gained (per individual investigated for TB) was $164 (95% uncertainty range $85, $452). In a sensitivity analysis that considered hospital discharge after a single negative Xpert®MTB/RIF, the Xpert®MTB/RIF scenario was cost saving. INTERPRETATION Adding Xpert®MTB/RIF to the current diagnostic algorithm for TB in Nunavut appears to reduce time to diagnosis and treatment at reasonable cost. It may be especially well suited to overcome some of the other logistical barriers that are unique to this and other remote communities.
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Affiliation(s)
- Olivia Oxlade
- Respiratory Epidemiology and Clinical Research Unit, Department of Epidemiology, McGill University, Montreal, QC, Canada
- McGill International Tuberculosis Centre, McGill University, Montreal, QC, Canada
| | - Jordan Sugarman
- Respiratory Epidemiology and Clinical Research Unit, Department of Epidemiology, McGill University, Montreal, QC, Canada
| | - Gonzalo G. Alvarez
- Clinical Epidemiology, The Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Division of Respirology, Department of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Madhukar Pai
- Respiratory Epidemiology and Clinical Research Unit, Department of Epidemiology, McGill University, Montreal, QC, Canada
- McGill International Tuberculosis Centre, McGill University, Montreal, QC, Canada
| | - Kevin Schwartzman
- Respiratory Epidemiology and Clinical Research Unit, Department of Epidemiology, McGill University, Montreal, QC, Canada
- McGill International Tuberculosis Centre, McGill University, Montreal, QC, Canada
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Chida N, Shah M. Infectious Diseases (ID) Learning Unit: How Rapidly to Evaluate for Active Tuberculosis Disease in Low-Prevalence Settings. Open Forum Infect Dis 2016; 3:ofw058. [PMID: 27186583 PMCID: PMC4866567 DOI: 10.1093/ofid/ofw058] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 02/25/2016] [Indexed: 12/03/2022] Open
Abstract
With declining tuberculosis (TB) incidence in low-prevalence settings, many clinicians are likely unaware that the approach to diagnosing active TB is evolving with newer technologies. Rapid molecular assays are commercially available, and more are likely to enter the market in the coming years. These tests, such as the Xpert MTB/RIF, which can detect TB and drug-resistance in 2 hours, are increasingly used in settings with higher TB prevalence; however, uptake has been slower in low-prevalence settings. Newer algorithms incorporating rapid TB diagnostics have the ability to alter current clinical and infection control practice patterns. In this learning unit, we review current and newly available tests for the detection of active TB disease and their usage in low-prevalence settings.
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Affiliation(s)
- Natasha Chida
- Department of Medicine, Division of Infectious Diseases , Johns Hopkins University , Baltimore, Maryland
| | - Maunank Shah
- Department of Medicine, Division of Infectious Diseases , Johns Hopkins University , Baltimore, Maryland
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Schumacher SG, Sohn H, Qin ZZ, Gore G, Davis JL, Denkinger CM, Pai M. Impact of Molecular Diagnostics for Tuberculosis on Patient-Important Outcomes: A Systematic Review of Study Methodologies. PLoS One 2016; 11:e0151073. [PMID: 26954678 PMCID: PMC4783056 DOI: 10.1371/journal.pone.0151073] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/23/2016] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Several reviews on the accuracy of Tuberculosis (TB) Nucleic Acid Amplification Tests (NAATs) have been performed but the evidence on their impact on patient-important outcomes has not been systematically reviewed. Given the recent increase in research evaluating such outcomes and the growing list of TB NAATs that will reach the market over the coming years, there is a need to bring together the existing evidence on impact, rather than accuracy. We aimed to assess the approaches that have been employed to measure the impact of TB NAATs on patient-important outcomes in adults with possible pulmonary TB and/or drug-resistant TB. METHODS We first develop a conceptual framework to clarify through which mechanisms the improved technical performance of a novel TB test may lead to improved patient outcomes and outline which designs may be used to measure them. We then systematically review the literature on studies attempting to assess the impact of molecular TB diagnostics on such outcomes and provide a narrative synthesis of designs used, outcomes assessed and risk of bias across different study designs. RESULTS We found 25 eligible studies that assessed a wide range of outcomes and utilized a variety of experimental and observational study designs. Many potentially strong design options have never been used. We found that much of the available evidence on patient-important outcomes comes from a small number of settings with particular epidemiological and operational context and that confounding, time trends and incomplete outcome data receive insufficient attention. CONCLUSIONS A broader range of designs should be considered when designing studies to assess the impact of TB diagnostics on patient outcomes and more attention needs to be paid to the analysis as concerns about confounding and selection bias become relevant in addition to those on measurement that are of greatest concern in accuracy studies.
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Affiliation(s)
- Samuel G. Schumacher
- McGill University Department of Epidemiology & Biostatistics, Montreal, Canada
- McGill International TB Centre, Montreal, Canada
| | - Hojoon Sohn
- McGill University Department of Epidemiology & Biostatistics, Montreal, Canada
- McGill International TB Centre, Montreal, Canada
| | - Zhi Zhen Qin
- McGill University Department of Epidemiology & Biostatistics, Montreal, Canada
- McGill International TB Centre, Montreal, Canada
| | - Genevieve Gore
- McGill University, Schulich Library of Science and Engineering, Montreal, Canada
| | - J. Lucian Davis
- UCSF Pulmonary & Critical Care Medicine, San Francisco, United States of America
| | - Claudia M. Denkinger
- McGill University Department of Epidemiology & Biostatistics, Montreal, Canada
- McGill International TB Centre, Montreal, Canada
- Beth Israel Deaconess Medical Centre, Division of Infectious Disease, Boston, MA, United States of America
| | - Madhukar Pai
- McGill University Department of Epidemiology & Biostatistics, Montreal, Canada
- McGill International TB Centre, Montreal, Canada
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Ankrah AO, van der Werf TS, de Vries EFJ, Dierckx RAJO, Sathekge MM, Glaudemans AWJM. PET/CT imaging of Mycobacterium tuberculosis infection. Clin Transl Imaging 2016; 4:131-144. [PMID: 27077068 PMCID: PMC4820496 DOI: 10.1007/s40336-016-0164-0] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 02/09/2016] [Indexed: 12/17/2022]
Abstract
Tuberculosis has a high morbidity and mortality worldwide. Mycobacterium tuberculosis (Mtb) has a complex pathophysiology; it is an aerobic bacillus capable of surviving in anaerobic conditions in a latent state for a very long time before reactivation to active disease. In the latent tuberculosis infection, the individual has no clinical evidence of active disease, but exhibits a hypersensitive response to proteins of Mtb. Only some 5–10 % of latently infected individuals appear to have reactivation of tuberculosis at any one time point after infection, and neither imaging nor immune tests have been shown to predict tuberculosis reactivation reliably. The complex pathology of the organism provides multiple molecular targets for imaging the infection and targeting therapy. Positron emission tomography (PET) integrated with computer tomography (CT) provides a unique opportunity to noninvasively image the whole body for diagnosing, staging and assessing therapy response in many infectious and inflammatory diseases. PET/CT is a powerful noninvasive tool that can rapidly provide three-dimensional views of disease deep within the body and conduct longitudinal assessment over time in one particular patient. Some PET tracers, such as 18F-fluorodeoxyglucose (18F-FDG), have been found to be useful in various infectious diseases for detection, assessing disease activity, staging and monitoring response to therapy. This tracer has also been used for imaging tuberculosis. 18F-FDG PET relies on the glucose uptake of inflammatory cells as a result of the respiratory burst that occurs with infection. Other PET tracers have also been used to image different aspects of the pathology or microbiology of Mtb. The synthesis of the complex cell membrane of the bacilli for example can be imaged with 11C-choline or 18F-fluoroethylcholine PET/CT while the uptake of amino acids during cell growth can be imaged by 3′-deoxy-3′-[18F]fluoro-l-thymidine. PET/CT provides a noninvasive and sensitive method of assessing histopathological information on different aspects of tuberculosis and is already playing a role in the management of tuberculosis. As our understanding of the pathophysiology of tuberculosis increases, the role of PET/CT in the management of this disease would become more important. In this review, we highlight the various tracers that have been used in tuberculosis and explain the underlying mechanisms for their use.
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Affiliation(s)
- Alfred O Ankrah
- Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Gronigen, The Netherlands ; Department of Nuclear Medicine, University of Pretoria, Pretoria, South Africa
| | - Tjip S van der Werf
- Department of Internal Medicine, Infectious Diseases, and Pulmonary Diseases and Tuberculosis, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Erik F J de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Gronigen, The Netherlands
| | - Rudi A J O Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Gronigen, The Netherlands
| | - Mike M Sathekge
- Department of Nuclear Medicine, University of Pretoria, Pretoria, South Africa
| | - Andor W J M Glaudemans
- Department of Nuclear Medicine and Molecular Imaging, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9700 RB Gronigen, The Netherlands
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