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Najjingo I, Muttamba W, Kirenga BJ, Nalunjogi J, Bakesiima R, Olweny F, Lusiba P, Katamba A, Joloba M, Ssengooba W. Comparison of GeneXpert cycle threshold values with smear microscopy and culture as a measure of mycobacterial burden in five regional referral hospitals of Uganda- A cross-sectional study. PLoS One 2019; 14:e0216901. [PMID: 31091275 PMCID: PMC6519814 DOI: 10.1371/journal.pone.0216901] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Accepted: 04/30/2019] [Indexed: 11/25/2022] Open
Abstract
Background Determining mycobacterial burden is important in assessing severity of disease, evaluating infectiousness and predicting patient treatment outcomes. Mycobacterial burden assessed by smear microscopy grade and time to culture positivity is clearly interpretable by most physicians. GeneXpert (Xpert) has been recommended by WHO as a first line tuberculosis (TB) diagnostic test as an alternative to smear microscopy. Xpert gives cycle threshold (Ct) values as a potential measure for mycobacterial burden. For physicians to clearly interpret Ct values as measures of mycobacterial burden, this study compared the Xpert quantification capabilities with those of smear microscopy and culture. The study also determined a linear relationship between Xpert Ct values and MGIT culture time to positivity (MGIT-TTP) and associated factors. A cut off Ct value which best predicts smear positivity was also determined using the Receiver Operator Curve analysis method. Results Excluding missing results and rifampicin resistant TB cases, a moderately strong correlation of 0.55 between Xpert Ct value and smear grade was obtained. A weak correlation of 0.37 was obtained between Xpert Ct values and MGIT time to positivity while that between Xpert Ct values and LJ culture was 0.34. The Xpert Ct values were found to increase by 2.57 for every unit increase in days to positive and HIV status was significantly associated with this relationship. A cut off Ct value of 23.62 was found to best predict smear positivity regardless of HIV status. Conclusion Our study findings show that GeneXpert Ct values are comparable to smear microscopy as a measure of M. tuberculosis burden and can be used to replace smear microscopy. However, given the low correlation between Xpert Ct value and culture positivity, Xpert Ct values cannot replace culture as a measure of M. tuberculosis burden among TB patients.
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Affiliation(s)
- Irene Najjingo
- Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda.,Lung Institute Makerere University, Kampala, Uganda
| | | | | | - Joanitah Nalunjogi
- Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Ritah Bakesiima
- Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Francis Olweny
- Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Pastan Lusiba
- Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Achilles Katamba
- Clinical Epidemiology Unit, School of Medicine, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Moses Joloba
- Department of Medical Microbiology, College of Health Sciences, Makerere University, Kampala, Uganda
| | - Willy Ssengooba
- Lung Institute Makerere University, Kampala, Uganda.,Department of Medical Microbiology, College of Health Sciences, Makerere University, Kampala, Uganda
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Luo D, Wang L, Liu H, Li L, Liao Y, Yi X, Yan X, Wan K, Zeng Y. Ribokinase screened from T7 phage displayed Mycobacterium tuberculosis genomic DNA library had good potential for the serodiagnosis of tuberculosis. Appl Microbiol Biotechnol 2019; 103:5259-5267. [PMID: 31069485 DOI: 10.1007/s00253-019-09756-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 03/05/2019] [Accepted: 03/07/2019] [Indexed: 12/13/2022]
Abstract
Tuberculosis caused by Mycobacterium tuberculosis (M. tuberculosis) is the leading cause of death among infectious diseases in the worldwide. Lack of more sensitive and effective diagnostic reagents has increased the awareness of rapid diagnosis for tuberculosis. In this study, T7 phage displayed genomic DNA library of M. tuberculosis was constructed to screen the antigens that specially bind with TB-positive serum from the whole genome of M. tuberculosis and to improve the sensitivity and specificity of tuberculosis serological diagnosis. After three rounds of biopanning, results of DNA sequencing and BLAST analysis showed that 19 positive phages displayed four different proteins and the occurrence frequency of the phage which displayed ribokinase was the highest. The results of indirect ELISA and dot immunoblotting indicated that representative phages could specifically bind to tuberculosis-positive serum. The prokaryotic expression vector containing the DNA sequence of ribokinase gene was then constructed and the recombinant protein was expressed and purified to evaluate the serodiagnosis value of ribokinase. The reactivity of the recombinant ribokinase with different clinical serum was detected and the sensitivities and specificities in tuberculosis serodiagnosis were 90% and 86%, respectively by screening serum from tuberculosis patients (n = 90) and uninfected individuals (n = 90) based on ELISA. Therefore, this study demonstrated that ribokinase had good potential for the serodiagnosis of tuberculosis.
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Affiliation(s)
- Dan Luo
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, 421001, People's Republic of China
| | - Li Wang
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, 421001, People's Republic of China
| | - Haican Liu
- State Key Laboratory for Infectious Disease Prevention and Control/National Institute for communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, People's Republic of China
| | - Lingling Li
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, 421001, People's Republic of China
| | - Yating Liao
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, 421001, People's Republic of China
| | - Xiaomei Yi
- Reproductive Medical Center, The Affiliated First Hospital, University of South China, Hengyang, 421001, People's Republic of China
| | - Xiaoliang Yan
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, 421001, People's Republic of China
| | - Kanglin Wan
- State Key Laboratory for Infectious Disease Prevention and Control/National Institute for communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, People's Republic of China.
| | - Yanhua Zeng
- Institute of Pathogenic Biology, Hengyang Medical College, Hunan Provincial Key Laboratory for Special Pathogens Prevention and Control, Hunan Province Cooperative Innovation Center for Molecular Target New Drug Study, University of South China, Hengyang, 421001, People's Republic of China.
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Cartridge Based Nucleic Acid Amplification Test: The Sherlock of Tuberculosis. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2019. [DOI: 10.22207/jpam.13.1.18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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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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Sharma S, Sheoran A, Gupta KB, Yadav A, Varma-Basil M, Sreenivas V, Chaudhary D, Mehta PK. Quantitative detection of a cocktail of mycobacterial MPT64 and PstS1 in tuberculosis patients by real-time immuno-PCR. Future Microbiol 2019; 14:223-233. [PMID: 30663893 DOI: 10.2217/fmb-2018-0284] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
AIM There is an urgent need to design a reliable diagnostic test for tuberculosis (TB). METHODS Real-time immuno-PCR (RT-I-PCR) assay was devised for the quantitative detection of a cocktail of mycobacterial MPT64 (Rv1980c) and PstS1 (Rv0934) in TB patients. RESULTS A broad dynamic range of 0.95 pg/ml-95 ng/ml of MPT64+PstS1 was detected in TB patients. In smear-positive (n = 59) and smear-negative (n = 42) pulmonary TB cases, sensitivities of 93.2 and 83.3% were observed, respectively with 92.8% specificity, whereas a sensitivity of 77.9% and a specificity of 91.3% were observed in extrapulmonary TB cases (n = 86). Furthermore, significantly reduced MPT64+PstS1 concentrations (p < 0.001) were noticed in patients on therapy by RT-I-PCR as compared with untreated patients. CONCLUSION Our RT-I-PCR assay revealed high sensitivity especially for the rapid diagnosis of smear-negative pulmonary TB and paucibacillary extrapulmonary TB samples, which could also monitor the dynamics of disease in patients on therapy.
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Affiliation(s)
- Suman Sharma
- Centre for Biotechnology, Maharshi Dayanand University, Rohtak-124001, India
| | - Abhishek Sheoran
- Department of Statistics, Ramanujan College, University of Delhi, New Delhi-110019, India
| | - Krishna B Gupta
- Department of TB & Respiratory Medicine, University of Health Sciences, Rohtak-124001, India
| | - Aparna Yadav
- Department of Microbiology, University of Health Sciences, Rohtak-124001, India
| | - Mandira Varma-Basil
- Microbiology Department, Vallabhbhai Patel Chest Institute, University of Delhi, New Delhi-110007, India
| | - Vishnubhatla Sreenivas
- Department of Biostatistics, All India Institute of Medical Sciences, New Delhi-110029, India
| | - Dhruva Chaudhary
- Department of Pulmonary & Critical Care Medicine, University of Health Sciences, Rohtak-124001, India
| | - Promod K Mehta
- Centre for Biotechnology, Maharshi Dayanand University, Rohtak-124001, India
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Berhanu RH, David A, da Silva P, Shearer K, Sanne I, Stevens W, Scott L. Performance of Xpert MTB/RIF, Xpert Ultra, and Abbott RealTi me MTB for Diagnosis of Pulmonary Tuberculosis in a High-HIV-Burden Setting. J Clin Microbiol 2018; 56:e00560-18. [PMID: 30305387 PMCID: PMC6258835 DOI: 10.1128/jcm.00560-18] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 09/30/2018] [Indexed: 11/20/2022] Open
Abstract
More sensitive tests are needed for the diagnosis of smear-negative and HIV-associated tuberculosis. This study compares the sensitivities and specificities of three molecular tests, namely, the Xpert MTB/RIF test, the Xpert Ultra (Ultra), and RealTime MTB (RT-MTB), in a high HIV prevalence setting. Symptomatic adults were recruited from three outpatient sites, and each provided 4 sputum specimens. The diagnostic performance of Xpert MTB/RIF, Ultra, and RT-MTB was evaluated, with culture as a reference standard. HIV infection occurred in 62% of patients, with a median CD4 count of 220 cells/µl. The Ultra test had the highest sensitivity of 89.3% (95% confidence interval [CI], 78.1 to 96) compared to those of the Xpert MTB/RIF at 82.1% (95% CI, 69.6 to 91.1; P = 0.12) and RT-MTB at 78.6% (95% CI, 65.6 to 88.4; P = 0.68). The specificity was highest with the Xpert MTB/RIF at 100% (95% CI, 98 to 100), followed by RealTime MTB at 96.7% (95% CI, 92.9 to 98.8; P = 0.03) and the Ultra at 95.6% (95% CI, 91.5 to 98.1; P = 0.08). In patients with smear-negative disease, the Ultra was more sensitive than the Xpert MTB/RIF (64.7% [95% CI, 38.3 to 85.8] versus 41.2% [95% CI, 18.4 to 67.1], respectively; P = 0.12), and RT-MTB performed equally to Xpert MTB/RIF. In a comparison of the Ultra and RT-MTB on the same sputum specimen pellets, the Ultra was more sensitive than RT-MTB in the overall cohort (88.9% [95% CI, 77.4 to 95.8] versus 77.8% [95% CI, 64.4 to 88], respectively; P = 0.03) and among people with HIV (87.5% [95% CI, 71 to 96.5] versus 68.6% [95% CI, 50 to 83.9], respectively; P = 0.03). Although these results did not reach statistical significance, they suggest that the Ultra is more sensitive than the Xpert MTB/RIF and RT-MTB, most prominently in smear-negative disease. This was accompanied by a loss of specificity.
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Affiliation(s)
- Rebecca H Berhanu
- Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Clinical HIV Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Anura David
- National Priority Program, National Health Laboratory Service, Johannesburg, South Africa
| | - Pedro da Silva
- National Priority Program, National Health Laboratory Service, Johannesburg, South Africa
| | - Kate Shearer
- Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Ian Sanne
- Health Economics and Epidemiology Research Office, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Clinical HIV Research Unit, Department of Internal Medicine, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- National Priority Program, National Health Laboratory Service, Johannesburg, South Africa
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Kilaru SC, Chenimilla NP, Syed U, Momin K, Kilaru H, Patil E, Nerurkar V. Role of Xpert MTB/RIF in Bronchoalveolar lavage fluid of sputum-scarce, suspected Pulmonary TB patients. J Clin Tuberc Other Mycobact Dis 2018; 14:7-11. [PMID: 31720410 PMCID: PMC6830156 DOI: 10.1016/j.jctube.2018.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 11/22/2018] [Accepted: 11/30/2018] [Indexed: 11/30/2022] Open
Abstract
Setting A prospective observational study conducted in Medical college hospital, in a high-TB- prevalence region of northern Telangana, India. Objective To know the diagnostic role of Xpert MTB/RIF assay in bronchoalveolar lavage fluid (BALF) in sputum-scarce, suspected pulmonary tuberculosis (PTB) patients. Design Study period was between October 2014 and March 2017. Suspected pulmonary tuberculosis patients aged 15 years or more, who were sputum-scarce and conforming to the inclusion criteria were submitted to bronchoscopy. BALF thus obtained was submitted to smear for acid fast bacilli (AFB) and Xpert MTB/RIF assay as index tests along with culture for Mycobacterium tuberculosis complex (MTBC). Culture for M. tuberculosis complex was considered as gold standard for the diagnosis of PTB. The sensitivity, specificity and predictive values were calculated for smear AFB and Xpert MTB/RIF assay. Results 56 of the 81 patients were included and evaluated in the final analysis. In 10 of these 56 patients PTB was confirmed by culture positivity. The sensitivity and specificity of Xpert MTB/RIF assay was 90% (9/10,95%CI 59.6- 98.2) and 52.2% (24/46, 95%CI 38. 1-65.9) respectively and that of the smear AFB was 60% (6/10, 95%CI 31.2–83.1) and 67.4% (31/46, 95%CI 53.0–79.1). All the patients considered ‘probable’ PTB (pending culture results), were administered antituberculous treatment and showed complete clinicoradiological improvement on follow up. Three of the 31 Xpert MTB/RIF positive patients were detected as resistance to rifampicin (RR). Conclusions Xpert MTB/RIF assay of BALF in the study cohort provides rapid diagnosis of Mycobacterium tuberculosis, and detection of rifampicin resistance at the very outset, aiding in selection of appropriate ATT regimen. In this context, it can be recommended as the first line investigation. Xpert MTB/RIF assay aided by HRCT Chest and suggestive clinical presentation may be helpful in early institution of ATT especially in smear negative, culture negative cases.
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Affiliation(s)
- Satish Chandra Kilaru
- Department of Respiratory Medicine, Prathima Institute of Medical Sciences, Karimnagar, Telangana, India
| | - Nagender Prasad Chenimilla
- Department of Respiratory Medicine, Prathima Institute of Medical Sciences, Karimnagar, Telangana, India
| | - Umair Syed
- Department of Respiratory Medicine, Prathima Institute of Medical Sciences, Karimnagar, Telangana, India
| | - Kashif Momin
- Department of Community Medicine, Prathima Institute of Medical Sciences, Karimnagar, Telangana, India
| | - Hemanth Kilaru
- Department of Respiratory Medicine, Prathima Institute of Medical Sciences, Karimnagar, Telangana, India
| | - Ekta Patil
- Department of Microbiology and Serology, SRL Diagnostics, Mumbai, India
| | - Vidya Nerurkar
- Department of Microbiology and Serology, SRL Diagnostics, Mumbai, India
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Fradejas I, Ontañón B, Muñoz-Gallego I, Ramírez-Vela M, López-Roa P. The value of xpert MTB/RIF-generated CT values for predicting the smear status of patients with pulmonary tuberculosis. J Clin Tuberc Other Mycobact Dis 2018; 13:9-12. [PMID: 31720405 PMCID: PMC6830157 DOI: 10.1016/j.jctube.2018.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2017] [Revised: 03/12/2018] [Accepted: 04/09/2018] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Smear microscopy is used to assess the patient's infectiousness at the time of initial diagnosis of pulmonary tuberculosis. However, its limited sensitivity and specificity highlights the need for new diagnostic strategies. The aim of our study was to assess the diagnostic accuracy of GX Ct value as a predictor of smear status and its usefulness to quantify mycobacterial load. METHODS All GX-positive sputum samples during a seven-year period were included in the study. Correlations among Ct values, smear status and TTD on liquid culture were calculated. An optimal Ct value for ruling in infectious patients was established. Clinical and radiological variables were also analyzed. RESULTS Sixty-eight samples from 65 patients were included. Ct value and TTD yielded a positive correlation (ρ = 0.714; p < 0.05), while Ct and smear grade yielded an inverse correlation (r = -0.71). An optimal Ct value for ruling in smear positive patients was established at 21.1 cycles (90.5% sensitivity, 61% specificity, 81% PPV and 78% NPV). CONCLUSIONS Our study confirms the value of GX Ct levels for quantifying mycobacterial load and demonstrates the added value of Ct as a predictor of positive smear status, especially at Ct values below 21.
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Affiliation(s)
- Isabel Fradejas
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Belén Ontañón
- Department of Clinical Laboratory, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Irene Muñoz-Gallego
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - M.J. Ramírez-Vela
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Paula López-Roa
- Department of Clinical Microbiology, Hospital Universitario 12 de Octubre, Madrid, Spain
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Meiring C, van Helden PD, Goosen WJ. TB Control in Humans and Animals in South Africa: A Perspective on Problems and Successes. Front Vet Sci 2018; 5:298. [PMID: 30542655 PMCID: PMC6277860 DOI: 10.3389/fvets.2018.00298] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 11/06/2018] [Indexed: 01/24/2023] Open
Abstract
Mycobacterium tuberculosis (M. tb) remains one of the most globally serious infectious agents for human morbidity and mortality, but with significant differences in prevalence across the globe. In many countries, the incidence is now low and declining, but control and eradication remain a distant view. Similarly, the prevalence of bovine TB caused by Mycobacterium bovis (M. bovis), varies significantly across regions, although unlike for M. tuberculosis, data are sparse. The reduction in incidence and prevalence and control of both human and bovine TB is difficult and costly, yet some countries have managed to do this with some success. This perspective will consider some of the critical control steps we now know to be important for the control of TB from M. tuberculosis in humans living in South Africa, where the incidence of TB is the highest currently experienced. Despite the high incidence of human TB, South Africa has been able to reduce this incidence remarkably in the past few years, despite limited resources and high HIV prevalence. We draw from our experience to ascertain whether we may learn useful lessons from control efforts for both diseases in order to suggest effective control measures for bovine TB.
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Affiliation(s)
- Christina Meiring
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
| | - Paul D van Helden
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
| | - Wynand J Goosen
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
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Dual-aptamer-based voltammetric biosensor for the Mycobacterium tuberculosis antigen MPT64 by using a gold electrode modified with a peroxidase loaded composite consisting of gold nanoparticles and a Zr(IV)/terephthalate metal-organic framework. Mikrochim Acta 2018; 185:543. [PMID: 30421038 DOI: 10.1007/s00604-018-3081-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/31/2018] [Indexed: 12/13/2022]
Abstract
An ultrasensitive aptasensor is described for the voltammetric determination of the Mycobacterium tuberculosis antigen MPT64 in human serum. Firstly, an amino-modified Zr(IV) based metal-organic framework (MOF; type UiO-66-NH2; made up from Zr6O32 units and 2-amino-terephthalate linkers) with a high specific surface was synthesized and used as the carrier of the gold nanoparticles and the aptamers. Then the signalling nanoprobe was fabricated after the horseradish peroxidase was cast on the nanomaterials. The two aptamers with synergistic effect on binding MPT64 were anchored on the gold electrode. Differential pulse voltammetry indicated that the peak current is highest if the ratio of the two aptamers is 1:1. The assay has a wide linear response range (0.02 to 1000 pg·mL-1 of MPT64) and a 10 fg·mL-1 detection limit at a working potential of around -96 mV (vs Ag/AgCl). The results show this biosensor to be a viable tool for detection of tuberculosis at an early stage. Graphical abstract Schematic presentation of the construction of the nanoprobe and biosensor. Firstly, the surface of UiO-66-NH2 was anchored to gold nanoparticles (AuNPs). A dual-aptamer and HRP were added to form the signalling nanoprobe (Aptamer/HRP/AuNPs/UiO-66-NH2). Then, the aptamers I and II were attached on the surface of gold electrode and 6-mercapto-1-hexanol was used to block the uncovered active site of the gold electrode. Finally, after incubation with MPT64, the signalling nanoprobe was dropped on the modified electrode and the DPV measurements was used for the analysis of Mycobacterium tuberculosis antigen MPT64. (PVP: poly(vinyl pyrrolidone); HRP: horseradish peroxidase; MCH: 6-Mercapto-1-hexanol; HQ: hydroquinone; BQ: benzoquinone).
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Möller M, Kinnear CJ, Orlova M, Kroon EE, van Helden PD, Schurr E, Hoal EG. Genetic Resistance to Mycobacterium tuberculosis Infection and Disease. Front Immunol 2018; 9:2219. [PMID: 30319657 PMCID: PMC6170664 DOI: 10.3389/fimmu.2018.02219] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 09/07/2018] [Indexed: 12/11/2022] Open
Abstract
Natural history studies of tuberculosis (TB) have revealed a spectrum of clinical outcomes after exposure to Mycobacterium tuberculosis, the cause of TB. Not all individuals exposed to the bacterium will become diseased and depending on the infection pressure, many will remain infection-free. Intriguingly, complete resistance to infection is observed in some individuals (termed resisters) after intense, continuing M. tuberculosis exposure. After successful infection, the majority of individuals will develop latent TB infection (LTBI). This infection state is currently (and perhaps imperfectly) defined by the presence of a positive tuberculin skin test (TST) and/or interferon gamma release assay (IGRA), but no detectable clinical disease symptoms. The majority of healthy individuals with LTBI are resistant to clinical TB, indicating that infection is remarkably well-contained in these non-progressors. The remaining 5-15% of LTBI positive individuals will progress to active TB. Epidemiological investigations have indicated that the host genetic component contributes to these infection and disease phenotypes, influencing both susceptibility and resistance. Elucidating these genetic correlates is therefore a priority as it may translate to new interventions to prevent, diagnose or treat TB. The most successful approaches in resistance/susceptibility investigation have focused on specific infection and disease phenotypes and the resister phenotype may hold the key to the discovery of actionable genetic variants in TB infection and disease. This review will not only discuss lessons from epidemiological studies, but will also focus on the contribution of epidemiology and functional genetics to human genetic resistance to M. tuberculosis infection and disease.
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Affiliation(s)
- Marlo Möller
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
| | - Craig J. Kinnear
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
| | - Marianna Orlova
- Program in Infectious Diseases and Immunity in Global Health, The Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- McGill International TB Centre, McGill University, Montreal, QC, Canada
- Departments of Medicine and Human Genetics, McGill University, Montreal, QC, Canada
| | - Elouise E. Kroon
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
| | - Paul D. van Helden
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
| | - Erwin Schurr
- Program in Infectious Diseases and Immunity in Global Health, The Research Institute of the McGill University Health Centre, Montreal, QC, Canada
- McGill International TB Centre, McGill University, Montreal, QC, Canada
- Departments of Medicine and Human Genetics, McGill University, Montreal, QC, Canada
| | - Eileen G. Hoal
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, DST-NRF Centre of Excellence for Biomedical Tuberculosis Research, South African Medical Research Council Centre for Tuberculosis Research, Stellenbosch University, Cape Town, South Africa
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Druszczynska M, Wawrocki S, Szewczyk R, Rudnicka W. Mycobacteria-derived biomarkers for tuberculosis diagnosis. Indian J Med Res 2018; 146:700-707. [PMID: 29664027 PMCID: PMC5926340 DOI: 10.4103/ijmr.ijmr_1441_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Tuberculosis (TB) remains an escalating problem worldwide. The current diagnostic methods do not always guarantee reliable diagnosis. TB treatment is a time-consuming process that requires the use of several chemotherapeutics, to which mycobacteria are becoming increasingly resistant. This article focuses on the potential utility of biomarkers of mycobacterial origin with potential implications for TB diagnosis. Properly standardized indicators could become new diagnostic tools, improving and streamlining the identification of Mycobacterium tuberculosis infection and the implementation of appropriate therapy. These markers can also potentially provide a quick confirmation of effectiveness of new anti-mycobacterial drugs and TB vaccines, leading to a possible application in practice.
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Affiliation(s)
- Magdalena Druszczynska
- Department of Immunology & Infectious Biology, Faculty of Biology & Environmental Protection, Institute of Microbiology, Biotechnology & Immunology, University of Lodz, Lodz, Poland
| | - Sebastian Wawrocki
- Department of Immunology & Infectious Biology, Faculty of Biology & Environmental Protection, Institute of Microbiology, Biotechnology & Immunology, University of Lodz, Lodz, Poland
| | - Rafal Szewczyk
- Department of Industrial Microbiology & Biotechnology, Faculty of Biology & Environmental Protection, Institute of Microbiology, Biotechnology & Immunology, University of Lodz, Lodz, Poland
| | - Wieslawa Rudnicka
- Department of Immunology & Infectious Biology, Faculty of Biology & Environmental Protection, Institute of Microbiology, Biotechnology & Immunology, University of Lodz, Lodz, Poland
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Togun TO, MacLean E, Kampmann B, Pai M. Biomarkers for diagnosis of childhood tuberculosis: A systematic review. PLoS One 2018; 13:e0204029. [PMID: 30212540 PMCID: PMC6136789 DOI: 10.1371/journal.pone.0204029] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 08/31/2018] [Indexed: 12/14/2022] Open
Abstract
Introduction As studies of biomarkers of tuberculosis (TB) disease provide hope for a simple, point-of-care test, we aimed to synthesize evidence on biomarkers for diagnosis of TB in children and compare their accuracy to published target product profiles (TPP). Methods We conducted a systematic review of biomarkers for diagnosis of pulmonary TB in exclusively paediatric populations, defined as age less than 15 years. PubMed, EMBASE and Web of Science were searched for relevant publications from January 1, 2000 to November 27, 2017. Studies using mixed adult and paediatric populations or reporting biomarkers for extrapulmonary TB were excluded. Study quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies—2 (QUADAS-2) framework. No meta-analysis was done because the published childhood TB biomarkers studies were mostly early stage studies and highly heterogeneous. Results The 29 studies included in this systematic review comprise 20 case-control studies, six cohort studies and three cross-sectional studies. These studies reported diverse and heterogeneous forms of biomarkers requiring different types of clinical specimen and laboratory assays. Majority of the studies (27/29 [93%]) either did not meet the criteria in at least one of the four domains of the QUADAS-2 reporting framework or the assessment was unclear. However, the diagnostic performance of biomarkers reported in 22 studies met one or both of the WHO-recommended minimal targets of 66% sensitivity and 98% specificity for a new diagnostic test for TB disease in children, and/or 90% sensitivity and 70% specificity for a triage test. Conclusion We found that majority of the biomarkers for diagnosis of TB in children are promising but will need further refining and optimization to improve their performances. As new data are emerging, stronger emphasis should be placed on improving the design, quality and general reporting of future studies investigating TB biomarkers in children.
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Affiliation(s)
- Toyin Omotayo Togun
- McGill International TB Centre, and Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
- * E-mail:
| | - Emily MacLean
- McGill International TB Centre, and Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
| | - Beate Kampmann
- Vaccines and Immunity Theme, Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, The Gambia
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel Street, London, United Kingdom
| | - Madhukar Pai
- McGill International TB Centre, and Department of Epidemiology, Biostatistics and Occupational Health, McGill University, Montreal, QC, Canada
- Manipal McGill Centre for Infectious Diseases, Manipal University, Manipal, India
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Chen Y, Cao S, Liu Y, Zhang X, Wang W, Li C. Potential role for Rv2026c- and Rv2421c- specific antibody responses in diagnosing active tuberculosis. Clin Chim Acta 2018; 487:369-376. [PMID: 30195451 DOI: 10.1016/j.cca.2018.09.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 09/04/2018] [Accepted: 09/05/2018] [Indexed: 10/28/2022]
Abstract
The current diagnostic methods for tuberculosis (TB) have several limitations. Although commercial serological tests based on antibody detection are available, their variable accuracies limit their roles in the clinic. The aim of this study was to discover the improved biomarkers for TB disease by investigating the serum profiles of IgG and IgM antibodies against nearly all Mycobacterium tuberculosis (MTB) antigens in 36 active TB patients and 18 healthy controls (HCs) using proteome microarrays. Our results revealed that multiple antigens could induce stronger serum IgG or IgM responses in TB patients compared to HCs, among them, Rv2026c and Rv2421c were further validated by ELISA with sera from 221 samples and showed the moderate performance in diagnosing TB by receiver operating characteristic analysis. Moreover, logistic regression analysis was performed to establish a combined panel that provided better sensitivity and specificity at 82.5% and 88.12%, respectively, than single antigens in the diagnosis of active TB. Furthermore, the antibody reactivity against Rv2026c and Rv2421c was correlated with clinical backgrounds. These results suggest that the combination of different antigens and classes of antibodies could provide promise and encouragement in developing an efficient serological test for the diagnosis of active TB.
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Affiliation(s)
- Yanqing Chen
- Institute for Geriatrics and Rehabilitation, Beijing Geriatric Hospital, Beijing University of Chinese Medicine, Beijing 100095, China.; Department of Laboratory Center, Beijing Children's Hospital, Capital Medical University, National Center for Children's Health, Beijing 100045, China
| | - Shuhui Cao
- Institute for Geriatrics and Rehabilitation, Beijing Geriatric Hospital, Beijing University of Chinese Medicine, Beijing 100095, China.; Department of Bacteriology and Immunology, Beijing Key Laboratory on Drug-Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute/Beijing Chest Hospital, Capital Medical University, Beijing 101149, China
| | - Yi Liu
- Institute for Geriatrics and Rehabilitation, Beijing Geriatric Hospital, Beijing University of Chinese Medicine, Beijing 100095, China
| | - Xuxia Zhang
- Institute for Geriatrics and Rehabilitation, Beijing Geriatric Hospital, Beijing University of Chinese Medicine, Beijing 100095, China
| | - Wei Wang
- Institute for Geriatrics and Rehabilitation, Beijing Geriatric Hospital, Beijing University of Chinese Medicine, Beijing 100095, China
| | - Chuanyou Li
- Institute for Geriatrics and Rehabilitation, Beijing Geriatric Hospital, Beijing University of Chinese Medicine, Beijing 100095, China..
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Zaidi SMA, Habib SS, Van Ginneken B, Ferrand RA, Creswell J, Khowaja S, Khan A. Evaluation of the diagnostic accuracy of Computer-Aided Detection of tuberculosis on Chest radiography among private sector patients in Pakistan. Sci Rep 2018; 8:12339. [PMID: 30120345 PMCID: PMC6098114 DOI: 10.1038/s41598-018-30810-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 07/31/2018] [Indexed: 11/09/2022] Open
Abstract
The introduction of digital CXR with automated computer-aided interpretation, has given impetus to the role of CXR in TB screening, particularly in low resource, high-burden settings. The aim of this study was to evaluate the diagnostic accuracy of CAD4TB as a screening tool, implemented in the private sector in Karachi, Pakistan. This study analyzed retrospective data from CAD4TB and Xpert MTB/RIF testing carried out at two private TB treatment and diagnostic centers in Karachi. Sensitivity, specificity, potential Xperts saved, were computed and the receiver operator characteristic curves were constructed for four different models of CAD4TB. A total of 6,845 individuals with presumptive TB were enrolled in the study, 15.2% of which had MTB + ve result on Xpert. A high sensitivity (range 65.8-97.3%) and NPV (range 93.1-98.4%) were recorded for CAD4TB. The Area under the ROC curve (AUC) for CAD4TB was 0.79. CAD4TB with patient demographics (age and gender) gave an AUC of 0.83. CAD4TB offered high diagnostic accuracy. In low resource settings, CAD4TB, as a triage tool could minimize use of Xpert. Using CAD4TB in combination with age and gender data enhanced the performance of the software. Variations in demographic information generate different individual risk probabilities for the same CAD4TB scores.
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Affiliation(s)
| | | | | | | | - Jacob Creswell
- StopTB Partnership, 1214 Geneva, 1214, Vernier, Switzerland
| | - Saira Khowaja
- Interactive Research & Development, Karachi, 75190, Pakistan
| | - Aamir Khan
- Interactive Research & Development, Karachi, 75190, Pakistan
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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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Nliwasa M, MacPherson P, Gupta‐Wright A, Mwapasa M, Horton K, Odland JØ, Flach C, Corbett EL. High HIV and active tuberculosis prevalence and increased mortality risk in adults with symptoms of TB: a systematic review and meta-analyses. J Int AIDS Soc 2018; 21:e25162. [PMID: 30063287 PMCID: PMC6067081 DOI: 10.1002/jia2.25162] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 06/21/2018] [Indexed: 12/18/2022] Open
Abstract
INTRODUCTION HIV and tuberculosis (TB) remain leading causes of preventable death in low- and middle-income countries (LMICs). The World Health Organization (WHO) recommends HIV testing for all individuals with TB symptoms, but implementation has been suboptimal. We conducted a systematic literature review and meta-analyses to estimate HIV and TB prevalence, and short-term (two to six months) mortality, among adults with TB symptoms at community- and facility level. METHODS We searched Embase, Global Health and MEDLINE databases, and reviewed conference abstracts for studies reporting simultaneous HIV and TB screening of adults in LMICs published between January 2003 and December 2017. Meta-analyses were performed to estimate prevalence of HIV, undiagnosed TB and mortality risk at different health system levels. RESULTS Sixty-two studies including 260,792 symptomatic adults were identified, mostly from Africa and Asia. Median HIV prevalence was 19.2% (IQR: 8.3% to 40.4%) at community level, 55.7% (IQR: 20.9% to 71.2%) at primary care level and 80.7% (IQR: 73.8% to 84.6%) at hospital level. Median TB prevalence was 6.9% (IQR: 3.3% to 8.4%) at community, 20.5% (IQR: 11.7% to 46.4%) at primary care and 36.4% (IQR: 22.9% to 40.9%) at hospital level. Median short-term mortality was 22.6% (IQR: 15.6% to 27.7%) among inpatients, 3.1% (IQR: 1.2% to 4.2%) at primary care and 1.6% (95% CI: 0.45 to 4.13, n = 1 study) at community level. CONCLUSIONS Adults with TB symptoms have extremely high prevalence of HIV infection, even when identified through community surveys. TB prevalence and mortality increased substantially at primary care and inpatient level respectively. Strategies to expand symptom-based TB screening combined with HIV and TB testing for all symptomatic individuals should be of the highest priority for both disease programmes in LMICs with generalized HIV epidemics. Interventions to reduce short-term mortality are urgently needed.
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Affiliation(s)
- Marriott Nliwasa
- Helse Nord Tuberculosis InitiativeDepartment of PathologyCollege of MedicineBlantyreMalawi
- Malawi‐Liverpool‐Welcome Trust Clinical Research ProgrammeBlantyreMalawi
- Clinical Research DepartmentLondon School of Hygiene & Tropical Medicine (LSHTM)LondonUK
| | - Peter MacPherson
- Department of Clinical SciencesLiverpool School of Tropical MedicineLiverpoolUK
| | - Ankur Gupta‐Wright
- Malawi‐Liverpool‐Welcome Trust Clinical Research ProgrammeBlantyreMalawi
- Clinical Research DepartmentLondon School of Hygiene & Tropical Medicine (LSHTM)LondonUK
| | - Mphatso Mwapasa
- Helse Nord Tuberculosis InitiativeDepartment of PathologyCollege of MedicineBlantyreMalawi
| | - Katherine Horton
- Clinical Research DepartmentLondon School of Hygiene & Tropical Medicine (LSHTM)LondonUK
| | - Jon Ø Odland
- Department of Community MedicineFaculty of Health SciencesUiT The Arctic University of NorwayTromsøNorway
- School of Public HealthUniversity of PretoriaPretoriaSouth Africa
| | - Clare Flach
- Department of Primary Care & Public Health SciencesKing's College LondonLondonUK
| | - Elizabeth L. Corbett
- Helse Nord Tuberculosis InitiativeDepartment of PathologyCollege of MedicineBlantyreMalawi
- Malawi‐Liverpool‐Welcome Trust Clinical Research ProgrammeBlantyreMalawi
- Clinical Research DepartmentLondon School of Hygiene & Tropical Medicine (LSHTM)LondonUK
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Prakash AK, Datta B, Tripathy JP, Kumar N, Chatterjee P, Jaiswal A. The clinical utility of cycle of threshold value of GeneXpert MTB/RIF (CBNAAT) and its diagnostic accuracy in pulmonary and extra-pulmonary samples at a tertiary care center in India. Indian J Tuberc 2018; 65:296-302. [PMID: 30522616 DOI: 10.1016/j.ijtb.2018.05.021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 05/23/2018] [Accepted: 05/24/2018] [Indexed: 12/19/2022]
Abstract
BACKGROUND There are knowledge gaps in the in-depth analysis of the most promising and robust diagnostic tool, GeneXpert MTB/RIF (CBNAAT). The cycle of threshold (CT) value of the CBNAAT test and its clinical implications has not been explored much. AIMS AND OBJECTIVES The study aimed at (a) estimating the diagnostic accuracy and incremental yield of Xpert MTB/RIF in various specimens (b) establishing the association between CT value category (high, medium, low, very low) and culture time-to-positivity (TTP). METHODS A total of 1000 samples, both pulmonary and extra-pulmonary were collected from presumptive TB cases in a large tertiary care hospital. Sensitivity and specificity of CBNAAT was calculated with culture as the gold standard. The association of CT value with culture TTP was also studied. RESULTS The overall sensitivity of CBNAAT was 88.5%, with bronchial washing specimen being the most sensitive (92.3%) and pleural fluid being the least (66.7%). In smear negative individuals, the sensitivity of CBNAAT was 80.9%. The additional yield of CBNAAT over smear microscopy was 10.9%. It was observed that as we move from high to very low CT category, culture positivity decreases significantly (p<0.001), whereas time taken for culture growth increases (p<0.001). CONCLUSION CBNAAT is a robust test for accurate diagnosis of tuberculosis both pulmonary and extra-pulmonary, smear negative as well, especially in resource-limited settings. The correlation between CT value and culture TTP has potential in predicting bacillary load, though further studies are required.
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Affiliation(s)
- Ashish K Prakash
- Department of Respiratory & Sleep Medicine, Medanta - The Medicity Gurgaon, India.
| | - B Datta
- Department of Respiratory & Sleep Medicine, Medanta - The Medicity Gurgaon, India
| | - J P Tripathy
- International Union Against Tuberculosis and Lung Disease, The Union South East Asia Office, New Delhi, India
| | - N Kumar
- Department of Microbiology, Medanta - The Medicity Gurgaon, India
| | - P Chatterjee
- Department of Respiratory & Sleep Medicine, Medanta - The Medicity Gurgaon, India
| | - A Jaiswal
- Department of Respiratory & Sleep Medicine, Medanta - The Medicity Gurgaon, India
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Gati S, Chetty R, Wilson D, Achkar JM. Utilization and Clinical Value of Diagnostic Modalities for Tuberculosis in a High HIV Prevalence Setting. Am J Trop Med Hyg 2018; 99:317-322. [PMID: 29893198 DOI: 10.4269/ajtmh.17-0965] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Human immunodeficiency virus (HIV) infection is a major risk factor for the development of active tuberculosis (TB), one of the deadliest infectious diseases globally. The high mortality associated with the disease can be reduced by early diagnosis and prompt antituberculous treatment initiation. Facilities in TB-endemic regions are increasing the use of nucleic acid amplification (e.g., GeneXpert), which provides rapid results but may have suboptimal sensitivity in HIV-associated TB. Our objective was to evaluate the current practices for TB diagnosis at Edendale Hospital, a large regional hospital in KwaZulu-Natal, South Africa-a TB-endemic region with high HIV prevalence. In this cross-sectional study, all adult inpatients newly started on TB treatment at Edendale were identified over a 6-week period. Demographics, clinical information, diagnostic test results, and outcomes were documented. Pulmonary TB (PTB), extrapulmonary TB (EXTB), and PTB + EXTB were defined as disease evidence in the lungs, other organs, or both, respectively. Ninety-four cases were identified, of which 83% were HIV-associated. Only 30% of all TB patients were microbiologically confirmed, consisting of 7/16 (44%) HIV-uninfected and 21/78 (27%) HIV-infected TB patients. Smear microscopy and mycobacterial culture were seldom ordered. Ultrasound was performed in about one-third of suspected EXTB cases and was valuable in identifying abdominal TB. In this clinical setting with a high incidence of HIV-associated TB, TB diagnosis was more commonly based on clinical assessment and imaging results than on mycobacterial gold standard test confirmation.
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Affiliation(s)
| | - Rhoda Chetty
- Department of Medicine, Edendale Hospital, University of KwaZulu-Natal, KwaZulu-Natal, South Africa
| | - Douglas Wilson
- Department of Medicine, Edendale Hospital, University of KwaZulu-Natal, KwaZulu-Natal, South Africa
| | - Jacqueline M Achkar
- Department of Immunology, Albert Einstein College of Medicine, Bronx, New York.,Department of Medicine, Albert Einstein College of Medicine, Bronx, New York.,Department of Microbiology, Albert Einstein College of Medicine, Bronx, New York
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Beynon F, Theron G, Respeito D, Mambuque E, Saavedra B, Bulo H, Sanz S, Dheda K, Garcia-Basteiro AL. Correlation of Xpert MTB/RIF with measures to assess Mycobacterium tuberculosis bacillary burden in high HIV burden areas of Southern Africa. Sci Rep 2018; 8:5201. [PMID: 29581435 PMCID: PMC5980110 DOI: 10.1038/s41598-018-23066-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 03/06/2018] [Indexed: 11/23/2022] Open
Abstract
Traditionally, smear microscopy has been used as a point-of-care measure of bacillary burden in tuberculosis patients to inform infection control and contact tracing. Xpert MTB/RIF has the potential to replace smear. However, data to support the use of its quantitative output [cycle threshold (CT)] as an alternate point-of-care measure of bacillary burden are limited. This study assessed the correlation (Spearman's) between CT, smear, culture time-to-positivity (TTP), and clinical factors in patients with Xpert-positive sputum from Mozambique (n = 238) and South Africa (n = 462). Mean CT and smear grade correlated well (ρ0.72); compared to TTP and smear (ρ0.61); and mean CT and TTP (ρ0.50). In multivariate analyses, lower CT (higher bacillary load) was associated with negative HIV serostatus and low BMI. A smear positivity rule-out (95% sensitivity) CT cut-off of 28.0 was identified, with 54.1% specificity, 2.07 positive likelihood ratio, 0.09 negative likelihood ratio and 79.0% correctly classified. Cut-offs were higher for HIV positive compared to HIV negative individuals for any set sensitivity level. This study suggests Xpert CT values correlate well with smear, both in HIV positive and negative individuals, and that CT cut-offs might be broadly applicable to multiple settings. Studies to directly assess the association of CT with infectiousness are needed.
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Affiliation(s)
- Fenella Beynon
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Grant Theron
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Durval Respeito
- Centro de Investigação em Saude de Manhiça (CISM). Rua 12, Cambeve CP 1929, Maputo, Mozambique
| | - Edson Mambuque
- Centro de Investigação em Saude de Manhiça (CISM). Rua 12, Cambeve CP 1929, Maputo, Mozambique
| | - Belen Saavedra
- Centro de Investigação em Saude de Manhiça (CISM). Rua 12, Cambeve CP 1929, Maputo, Mozambique
| | - Helder Bulo
- Centro de Investigação em Saude de Manhiça (CISM). Rua 12, Cambeve CP 1929, Maputo, Mozambique
| | - Sergi Sanz
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Keertan Dheda
- DST/NRF Centre of Excellence for Biomedical Tuberculosis Research, MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Alberto L Garcia-Basteiro
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
- Centro de Investigação em Saude de Manhiça (CISM). Rua 12, Cambeve CP 1929, Maputo, Mozambique.
- Amsterdam Institute for Global Health and Development (AIGHD), Academic Medical Center, Amsterdam, The Netherlands.
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Accuracy of different Xpert MTB/Rif implementation strategies in programmatic settings at the regional referral hospitals in Uganda: Evidence for country wide roll out. PLoS One 2018; 13:e0194741. [PMID: 29566056 PMCID: PMC5864038 DOI: 10.1371/journal.pone.0194741] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/08/2018] [Indexed: 12/20/2022] Open
Abstract
Background Xpert MTB/RIF assay is a highly sensitive test for TB diagnosis, but still costly to most low-income countries. Several implementation strategies instead of frontline have been suggested; however with scarce data. We assessed accuracy of different Xpert MTB/RIF implementation strategies to inform national roll-out. Methods This was a cross-sectional study of 1,924 adult presumptive TB patients in five regional referral hospitals of Uganda. Two sputum samples were collected, one for fluorescent microscopy (FM) and Xpert MTB/RIF examined at the study site laboratories. The second sample was sent to the Uganda Supra National TB reference laboratory for culture using both Lowenstein Jensen (LJ) and liquid culture (MGIT). We compared the sensitivities of FM, Xpert MTB/RIF and the incremental sensitivity of Xpert MTB/RIF among patients negative on FM using LJ and/or MGIT as a reference standard. Results A total 1924 patients were enrolled of which 1596 (83%) patients had at least one laboratory result and 1083 respondents had a complete set of all the laboratory results. A total of 328 (30%) were TB positive on LJ and /or MGIT culture. The sensitivity of FM was n (%; 95% confidence interval) 246 (63.5%; 57.9–68.7) overall compared to 52 (55.4%; 44.1–66.3) among HIV positive individuals, while the sensitivity of Xpert MTB/RIF was 300 (76.2%; 71.7–80.7) and 69 (71.6%; 60.5–81.1) overall and among HIV positive individuals respectively. Overall incremental sensitivity of Xpert MTB/RIF was 60 (36.5%; 27.7–46.0) and 20 (41.7%; 25.5–59.2) among HIV positive individuals. Conclusion Xpert MTB/RIF has a higher sensitivity than FM both in general population and HIV positive population. Xpert MTB/RIF offers a significant increase in terms of diagnostic sensitivity even when it is deployed selectively i.e. among smear negative presumptive TB patients. Our results support frontline use of Xpert MTB/RIF assay in high HIV/TB prevalent countries. In settings with limited access, mechanisms to refer smear negative sputum samples to Xpert MTB/RIF hubs are recommended.
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Pan X, Yang S, Deighton MA, Qu Y, Hong L, Su F. A Comprehensive Evaluation of Xpert MTB/RIF Assay With Bronchoalveolar Lavage Fluid as a Single Test or Combined With Conventional Assays for Diagnosis of Pulmonary Tuberculosis in China: A Two-Center Prospective Study. Front Microbiol 2018; 9:444. [PMID: 29593688 PMCID: PMC5859353 DOI: 10.3389/fmicb.2018.00444] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 02/26/2018] [Indexed: 11/13/2022] Open
Abstract
Introduction: The Xpert MTB/RIF is recommended by the World Health Organization as a first line rapid test for the diagnosis of pulmonary tuberculosis (TB); however, China does not routinely use this test, partially due to the lack of a sufficient number of systematic evaluations of this assay in local patients. The aims of this study were to comprehensively assess the diagnostic performance of Xpert MTB/RIF, either alone or in combination with conventional assays for the diagnosis of pulmonary TB in adult Chinese patients. Methods: Xpert MTB/RIF tests were performed in 190 adult patients with suspected pulmonary TB, using bronchoalveolar lavage fluid (BALF) as test specimens. In parallel, conventional tests were carried out using the same BALF samples. Using two different reference standards, the performance of Xpert MTB/RIF, conventional assays and their combinations were evaluated. Results: Using mycobacterial culture as the reference comparator, Xpert MTB/RIF was found to be superior to smear-microscopy in detecting Mycobacterium tuberculosis. When final diagnosis, based on clinical criteria, was employed as the reference standard, Xpert MTB/RIF showed an even higher accuracy of 72.1%, supported by a sensitivity of 61.1% and specificity of 96.6%. Xpert MTB/RIF also demonstrated a powerful capability to identify pulmonary TB cases undetected by culture or smear-microscopy. Combining smear-microscopy and Xpert MTB/RIF was found to be the most accurate early predictor for pulmonary TB. Rifampicin resistance reported by Xpert MTB/RIF slightly deviated from that by phenotypic antibiotic susceptibility testing and requires further study with a larger sample size. Conclusion: This two-center prospective study highlights the value of Xpert MTB/RIF with BALF in diagnosing pulmonary TB in adult Chinese patients. These findings might contribute to the optimization of current diagnostic algorithms for pulmonary TB in China.
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Affiliation(s)
- Xiaofu Pan
- Department of Laboratory Medicine, The Third Affiliated Hospital of the Wenzhou Medical University, Rui'an, China
| | - Shoufeng Yang
- Department of Infectious Diseases, Wenzhou Central Hospital, Zhejiang, China
| | | | - Yue Qu
- Department of Laboratory Medicine, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, China.,Biomedicine Discovery Institute, Department of Microbiology, School of Medicine, Nursing and Health Sciences, Monash University, Clayton, VIC, Australia
| | - Liang Hong
- Department of Infectious Diseases, The Third Affiliated Hospital of Wenzhou Medical University, Rui'an, China
| | - Feifei Su
- Department of Infectious Diseases, Wenzhou Central Hospital, Zhejiang, China
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Point of care diagnostics for tuberculosis. Pulmonology 2018; 24:73-85. [DOI: 10.1016/j.rppnen.2017.12.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 12/07/2017] [Indexed: 01/01/2023] Open
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Shrestha P, Khanal H, Dahal P, Dongol P. Programmatic Impact of Implementing GeneXpert MTB/ RIF Assay for the Detection of Mycobacterium Tuberculosis in Respiratory Specimens from Pulmonary Tuberculosis Suspected Patients in Resource Limited Laboratory Settings of Eastern Nepal. Open Microbiol J 2018. [PMID: 29541267 PMCID: PMC5842389 DOI: 10.2174/1874285801812010009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Background In Nepal, introduction of GeneXpert MTB/RIF assay (Xpert assay) as an initial confirmation test for tuberculosis (TB) has been considered to have impact as a significant decrease in number of clinically diagnosed pulmonary tuberculosis (PTB) cases than previous years. This study aims to find out the distribution profile of suspected tuberculosis cases according to patients age, gender, treatment history and HIV status as well as to evaluate the utility of the Xpert assay over conventional acid-fast bacilli (AFB) staining method for the proper diagnosis of M. Tuberculosis in respiratory specimens from the tuberculosis (TB) suspected patient samples. Methods The prospective cross-sectional analytical study was conducted in National Anti-Tuberculosis Center (NATA) center- Biratnagar and Primary Healthcare Center (PHC) - Manglabare, Morang District, of eastern Nepal from January 2014 to August 2014. Laboratory investigation was done by conventional AFB staining followed by Xpert assay. Results A total of 1549 sputum samples were initially analyzed. AFB staining resulted in 1441 AFB smear negative samples and 88 AFB smear positive samples, whereas 20 samples were directly processed for Xpert assay. The male: female smear positive ratio was 2.8:1 and was higher among age groups (21-40) years. Tuberculosis among HIV patients was found 22.22%. Xpert assay demonstrates that out of 1441 smear negative AFB cases, 258 were found to have TB positive, whereas out of 88 smears positive AFB cases 12 were found to have TB negative. The sensitivity of the Xpert assay in patients classified as AFB smear positive was found 85.4% and the specificity in smear negative patients was 81%. Conclusion The study concluded that implementation of Gene Xpert MTB/RIF assay is a helpful tool for early and rapid detection of tuberculosis with greater sensitivity and specificity over traditional AFB staining techniques.
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Affiliation(s)
- Prakash Shrestha
- Department of microbiology, Sunsari Technical College, Dharan-4, Sunsari, Nepal
| | - Hemanta Khanal
- Central Campus of Technology, Tribhuvan University, Hattisar, Dharan, Sunsari, Nepal
| | - Prasanna Dahal
- Department of Pharmacy, Tribhuvan University, Dharan-4, Sunsari, Nepal
| | - Pranita Dongol
- Department of microbiology, Sunsari Technical College, Dharan-4, Sunsari, Nepal
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Kawkitinarong K, Suwanpimolkul G, Kateruttanakul P, Manosuthi W, Ubolyam S, Sophonphan J, Avihingsanon A, Ruxrungtham K. Real-Life Clinical Practice of Using the Xpert MTB/RIF Assay in Thailand. Clin Infect Dis 2018; 64:S171-S178. [PMID: 28475796 DOI: 10.1093/cid/cix151] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Background Delayed diagnosis of tuberculosis (TB) and drug-resistant TB are major challenges of TB control in Thailand. This study assessed the practicality of the Xpert MTB/RIF assay in a real-life setting with high prevalence of human immunodeficiency virus (HIV) infection and pulmonary tuberculosis (PTB). Methods This prospective study was conducted at 3 large tertiary care hospitals. Patients who had suspected PTB were enrolled into the study. Expectorated sputum samples were sent for staining, mycobacterial culture, and Xpert MTB/RIF. Results Four hundred ninety-four patients were enrolled. From 355 cases with final diagnosis of PTB, 263 (71.8%) had definite diagnosis and 92 cases had probable diagnosis. Among TB culture-positive cases, Xpert MTB/RIF had 100% and 81% sensitivity in sputum smear-positive and smear-negative groups, respectively. The specificity was 95.7%. The sensitivity and positive predictive value of Xpert MTB/RIF in culture-negative but clinically diagnosed PTB was 37.8% and 83.8%, respectively. Centrifugation was required in 59% cases with scanty sputum. Five cases were false-positive by Xpert MTB/RIF in patients with nontuberculous mycobacteria, old PTB scar, and immune reconstitution syndrome. Discordant rifampicin susceptibility results of Xpert MTB/RIF and mycobacteria growth indicator tube (MGIT) were confirmed by using rpoB gene sequencing, which raised the sensitivity of Xpert MTB/RIF in detecting rifampicin resistance to 93.8%. Conclusions Xpert MTB/RIF is an effective tool in diagnosing PTB but will be more cost-effective for sputum-negative patients and in settings with high prevalence of rifampicin resistance. Early diagnosis of TB results in early treatment and implementation of strategies to limit spreading of TB. Sputum centrifugation may increase the yield of Xpert MTB/RIF.
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Affiliation(s)
- Kamon Kawkitinarong
- Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, and
| | - Gompol Suwanpimolkul
- Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, and
| | | | - Weerawat Manosuthi
- Bamrasnaradura Infectious Diseases Institute, Ministry of Public Health, Nonthaburi; and
| | - Sasiwimol Ubolyam
- HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT), Thai Red Cross AIDS Research Centre, Bangkok, Thailand
| | - Jiratchaya Sophonphan
- HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT), Thai Red Cross AIDS Research Centre, Bangkok, Thailand
| | - Anchalee Avihingsanon
- Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, and.,HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT), Thai Red Cross AIDS Research Centre, Bangkok, Thailand
| | - Kiat Ruxrungtham
- Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, and.,HIV Netherlands Australia Thailand Research Collaboration (HIV-NAT), Thai Red Cross AIDS Research Centre, Bangkok, Thailand
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Metcalfe JZ, Makumbirofa S, Makamure B, Sandy C, Bara W, Mason P, Hopewell PC. Xpert(®) MTB/RIF detection of rifampin resistance and time to treatment initiation in Harare, Zimbabwe. Int J Tuberc Lung Dis 2018; 20:882-9. [PMID: 27287639 DOI: 10.5588/ijtld.15.0696] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Patients at elevated risk of drug-resistant tuberculosis (TB) are prioritized for Xpert(®) MTB/RIF testing; however, the clinical usefulness of the test in this population is understudied. DESIGN From November 2011 to June 2014, consecutive out-patients with a history of previous TB in high-density suburbs of Harare, Zimbabwe, were tested using Xpert, solid and liquid culture, and the microscopic observation drug susceptibility assay. Diagnostic accuracy for rifampin (RMP) resistance and time to initiation of second-line regimens were ascertained. The rpoB gene was sequenced in cases with culture-confirmed RMP resistance and genotypic susceptibility. RESULTS Among 352 retreatment patients, 71 (20%) were RMP-resistant, 98 (28%) RMP-susceptible, 64 (18%) culture-negative/Xpert-positive, and 119 (34%) culture-negative/Xpert-negative. Xpert had a sensitivity of 86% (95%CI 75-93) and a specificity of 98% (95%CI 92-100) for RMP-resistant TB. The positive predictive value of Xpert-determined RMP resistance for multidrug-resistant TB (MDR-TB) was 82% (95%CI 70-91). Of 71 (83%) participants, 59 initiated treatment with second-line drugs, with a median time to treatment initiation of 18 days (IQR 10-44). CONCLUSION The diagnostic accuracy of Xpert for RMP resistance is high, although the predictive value for MDR-TB was lower than anticipated. Xpert allows for faster initiation of second-line treatment than culture-based drug susceptibility testing under programmatic conditions.
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Affiliation(s)
- J Z Metcalfe
- Curry International Tuberculosis Center, Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California, San Francisco, California, USA
| | - S Makumbirofa
- Biomedical Research & Training Institute, Harare, Zimbabwe
| | - B Makamure
- Biomedical Research & Training Institute, Harare, Zimbabwe
| | - C Sandy
- National Tuberculosis Control Program, Harare, Zimbabwe
| | - W Bara
- Harare City Health Department, Harare, Zimbabwe
| | - P Mason
- Biomedical Research & Training Institute, Harare, University of Zimbabwe College of Health Sciences, Harare, Zimbabwe
| | - P C Hopewell
- Curry International Tuberculosis Center, Division of Pulmonary and Critical Care Medicine, San Francisco General Hospital, University of California, San Francisco, California, USA
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Mugomeri E, Bekele BS, Maibvise C, Tarirai C. Trends in diagnostic techniques and factors associated with tuberculosis treatment outcomes in Lesotho, 2010–2015. S Afr J Infect Dis 2018. [DOI: 10.1080/23120053.2017.1376545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Eltony Mugomeri
- Faculty of Health Sciences, Department of Pharmacy, National University of Lesotho, Maseru, Lesotho
| | - Bisrat S Bekele
- Faculty of Health Sciences, Department of Pharmacy, National University of Lesotho, Maseru, Lesotho
| | - Charles Maibvise
- Faculty of Health Sciences, Department of Nursing, University of Swaziland, Mbabane, Swaziland
| | - Clemence Tarirai
- Department of Pharmaceutical Sciences, Tshwane University of Technology, Pretoria, South Africa
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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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Patel K, Nagel M, Wesolowski M, Dees S, Rivera-Milla E, Geldmacher C, Dheda K, Hoelscher M, Labugger I. Evaluation of a Urine-Based Rapid Molecular Diagnostic Test with Potential to Be Used at Point-of-Care for Pulmonary Tuberculosis: Cape Town Cohort. J Mol Diagn 2017; 20:215-224. [PMID: 29269279 DOI: 10.1016/j.jmoldx.2017.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 10/02/2017] [Accepted: 11/22/2017] [Indexed: 10/18/2022] Open
Abstract
Tuberculosis (TB) diagnosis among sputum-scarce patients is time consuming. Thus, a nonsputum diagnostic alternative is urgently needed. The Mycobacterium tuberculosis-specific transrenal (Tr) DNA from urine is a potential target for TB diagnostics. In this study, a new urine-based Tr-DNA molecular assay was evaluated for diagnosis of pulmonary tuberculosis among 428 adults suspected of having pulmonary TB (164 HIV positive, 263 HIV negative) from Cape Town, South Africa. Tr-DNA was isolated from 4 mL of EDTA urine, and a rapid, double-stranded, primer-based PCR method was performed targeting the Mycobacterium tuberculosis-specific direct repeat region. Each Tr-DNA eluate was tested in triplicate using an automated molecular analyzer with controls included in each test. With liquid culture used as the gold standard, the Tr-DNA assay showed sensitivity of 42.9% (n = 75/175; 95% CI, 35.4%-50.5%) and specificity of 88.6% (n = 210/237; 95% CI, 83.9%-92.4%). Among HIV-infected patients with TB, sensitivity and specificity were 45.2% and 89.0%, respectively. The combination of smear microscopy and Tr-DNA increased the sensitivity to 83.8% (smear microscopy alone, 75.1%), with 96.6% specificity. This study indicates that Tr-DNA has a moderate specificity with low sensitivity for diagnosis of pulmonary TB. Despite low sensitivity, this diagnostic test may have potential in combination with smear microscopy to support TB diagnosis in HIV-endemic regions, where sputum-scarce patients are common.
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Affiliation(s)
- Krutarth Patel
- Alere Technologies GmbH, Jena, Germany; Center for International Health, University of Munich, Munich, Germany.
| | | | | | | | | | - Christof Geldmacher
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany; German Center for Infection Research, Munich, Germany
| | - Keertan Dheda
- Lung Infection and Immunity Unit, Division of Pulmonology & Clinical Immunology, Department of Medicine and UCT Lung Institute, University of Cape Town, Cape Town, South Africa
| | - Michael Hoelscher
- Center for International Health, University of Munich, Munich, Germany; Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany; German Center for Infection Research, Munich, Germany
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82
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Schluger NW. AJRCCM: 100-Year Anniversary. Focus on Tuberculosis. Am J Respir Crit Care Med 2017; 195:1112-1114. [PMID: 28459341 DOI: 10.1164/rccm.201703-0446ed] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Neil W Schluger
- 1 Department of Medicine.,2 Department of Epidemiology and.,3 Department of Environmental Health Science Columbia University New York, New York
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83
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Cayci YT, Bilgin K, Coban AY, Birinci A, Durupınar B. An evaluation of false-positive rifampicin resistance on the Xpert MTB/RIF. Mem Inst Oswaldo Cruz 2017; 112:756-759. [PMID: 29091135 PMCID: PMC5661898 DOI: 10.1590/0074-02760170051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 07/07/2017] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Mycobacterium tuberculosis (MTB) is one of the most significant causes of mortality and morbidity. Early diagnose is important especially in multiple drug resistant tuberculosis to avoid transmission. Traditional techniques requires at least one to three weeks for diagnosis of tuberculosis. Diagnostic delays with multiple drug resistant tuberculosis are associated with worse clinical outcomes and increased transmission The Xpert MTB/RIF assay is one of the new diagnostic device for the diagnosis of tuberculosis and rapid detection of rifampicin resistance. OBJECTIVE We assessed the performance of Xpert MTB/RIF assay for detecting rifampicin resistance using phenotypic drug susceptibility tests as automated BD MGIT 960. METHODS Total of 2136 specimens were included in the study. Xpert MTB/RIF testing was performed on samples, using version 4 cartridges, according to the manufacturer's recommendations. The MTBC culture and first-line phenotypic DST were performed in automated BD MGIT 960 (Becton & Dickinson, USA) according to the recommendations of the manufacturer. Agar proportion was used in the case of inconsistency for rifampicin resistance. FINDINGS Thirty-four samples (19 respiratory and 15 nonrespiratory samples) were determined as positive for M. tuberculosis complex by Xpert MTB/RIF (Cepheid GeneXpert® System, USA). Xpert MTB/RIF assay detected 4/34 (11.7%) specimens as rifampicin resistant. One of the rifampicin resistant isolates was determined susceptible in MGIT 960 automated system. This isolate was also tested with agar proportion method and found susceptible to rifampicin. MAIN CONCLUSION The Xpert MTB/RIF assay can be used as first-line assay for the detection of M. tuberculosis. However, microbiologists must be aware of the limitations of the assay.
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Affiliation(s)
- Yeliz Tanriverdi Cayci
- Ondokuz Mayis University, Medical Faculty, Department of Medical Microbiology, Samsun, Turkey
| | - Kemal Bilgin
- Ondokuz Mayis University, Vocational School of Health Services, Department of Medical Services and Techniques, Samsun, Turkey
| | - Ahmet Yilmaz Coban
- Ondokuz Mayis University, Medical Faculty, Department of Medical Microbiology, Samsun, Turkey
| | - Asuman Birinci
- Ondokuz Mayis University, Medical Faculty, Department of Medical Microbiology, Samsun, Turkey
| | - Belma Durupınar
- Ondokuz Mayis University, Medical Faculty, Department of Medical Microbiology, Samsun, Turkey
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Fan J, Zhang H, Nguyen DT, Lyon CJ, Mitchell CD, Zhao Z, Graviss EA, Hu Y. Rapid diagnosis of new and relapse tuberculosis by quantification of a circulating antigen in HIV-infected adults in the Greater Houston metropolitan area. BMC Med 2017; 15:188. [PMID: 29089034 PMCID: PMC5664577 DOI: 10.1186/s12916-017-0952-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Accepted: 10/04/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND HIV-associated immune defects inhibit tuberculosis (TB) diagnosis, promote development of extrapulmonary TB and paucibacillary pulmonary TB cases with atypical radiographic features, and increase TB relapse rates. We therefore assessed the diagnostic performance of a novel assay that directly quantitates serum levels of the Mycobacterium tuberculosis (Mtb) virulence factor 10-kDa culture filtrate protein (CFP-10) to overcome limitations associated with detecting Mtb bacilli in sputum or tissue biopsies. METHODS This study analyzed HIV-positive adults enrolled in a large, population-based TB screening and surveillance project, the Houston Tuberculosis Initiative, between October 1995 and September 2004, and assigned case designations using standardized criteria. Serum samples were trypsin-digested and immunoprecipitated for an Mtb-specific peptide of CFP-10 that was quantified by liquid chromatography-mass spectrometry for rapid and sensitive TB diagnosis. RESULTS Among the 1053 enrolled patients, 110 met all inclusion criteria; they included 60 tuberculosis cases (12 culture-negative TB), including 9 relapse TB cases, and 50 non-TB controls, including 15 cases with history of TB. Serum CFP-10 levels diagnosed 89.6% (77.3-96.5) and 66.7% (34.9-90.1) of culture-positive and culture-negative TB cases, respectively, and exhibited 88% (75.7-95.5) diagnostic specificity in all non-TB controls. Serum antigen detection and culture, respectively, identified 85% (73.4-92.9) and 80.0% (67.3-88.8) of all 60 TB cases. CONCLUSIONS Quantitation of the Mtb virulence factor CFP-10 in serum samples of HIV-infected subjects diagnosed active TB cases with high sensitivity and specificity and detected cases missed by the gold standard of Mtb culture. These results suggest that serum CFP-10 quantitation holds great promise for the rapid diagnosis of suspected TB cases in patients who are HIV-infected.
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Affiliation(s)
- Jia Fan
- School of Biological and Health Systems Engineering, Virginia G. Piper Biodesign Center for Personalized Diagnostics, The Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Hedong Zhang
- Department of Nanomedicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
| | - Duc T Nguyen
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
| | - Christopher J Lyon
- School of Biological and Health Systems Engineering, Virginia G. Piper Biodesign Center for Personalized Diagnostics, The Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA
| | - Charles D Mitchell
- University of Miami, Leonard M. Miller School of Medicine, Miami, FL, 33136, USA
| | - Zhen Zhao
- Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Edward A Graviss
- Department of Pathology and Genomic Medicine, Houston Methodist Research Institute, Houston, TX, 77030, USA
| | - Ye Hu
- School of Biological and Health Systems Engineering, Virginia G. Piper Biodesign Center for Personalized Diagnostics, The Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.
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EVALUATION OF CARTRIDGE BASED NUCLEIC ACID AMPLIFICATION TEST IN DIAGNOSIS OF PULMONARY TUBERCULOSIS. ACTA ACUST UNITED AC 2017. [DOI: 10.14260/jemds/2017/1147] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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86
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Horo K, N’Guessan R, Koffi MO, Kouamé-N’Takpé N, Koné A, Samaké K, Koffi L, Ahui B, Brou-Gode C, N’Gom A, Kouassi B, Koffi N, Aka-Danguy E. Test Xpert ® MTB/RIF et dépistage des nouveaux cas de tuberculose pulmonaire en routine dans une zone de haute endémicité tuberculeuse. Rev Mal Respir 2017; 34:749-757. [DOI: 10.1016/j.rmr.2016.10.874] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Accepted: 10/22/2016] [Indexed: 10/20/2022]
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87
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Potential of High-Affinity, Slow Off-Rate Modified Aptamer Reagents for Mycobacterium tuberculosis Proteins as Tools for Infection Models and Diagnostic Applications. J Clin Microbiol 2017; 55:3072-3088. [PMID: 28794178 PMCID: PMC5625393 DOI: 10.1128/jcm.00469-17] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Accepted: 07/11/2017] [Indexed: 01/12/2023] Open
Abstract
Direct pathogen detection in blood to diagnose active tuberculosis (TB) has been difficult due to low levels of circulating antigens or due to the lack of specific, high-affinity binding reagents and reliable assays with adequate sensitivity. We sought to determine whether slow off-rate modified aptamer (SOMAmer) reagents with subnanomolar affinity for Mycobacterium tuberculosis proteins (antigens 85A, 85B, 85C, GroES, GroEL2, DnaK, CFP10, KAD, CFP2, RplL, and Tpx) could be useful to diagnose tuberculosis. When incorporated into the multiplexed, array-based proteomic SOMAscan assay, limits of detection reached the subpicomolar range in 40% serum. Binding to native M. tuberculosis proteins was confirmed by using M. tuberculosis culture filtrate proteins and fractions from infected macrophages and via affinity capture assays and subsequent mass spectrometry. Comparison of serum from culture-positive pulmonary TB patients and TB suspects systematically ruled out for TB revealed small but statistically significant (P < 0.0001) differences in the median M. tuberculosis signals and in specific pathogen markers, such as antigen 85B. Samples where many M. tuberculosis aptamers produced high signals were rare exceptions. In concentrated, protein-normalized urine from TB patients and non-TB controls, the CFP10 (EsxB) SOMAmer yielded the most significant differential signals (P < 0.0276), particularly in TB patients with HIV coinfection. In conclusion, direct M. tuberculosis antigen detection proved difficult even with a sensitive method such as SOMAscan, likely due to their very low, subpicomolar abundance. The observed differences between cases and controls had limited diagnostic utility in serum and urine, but further evaluation of M. tuberculosis SOMAmers using other platforms and sample types is warranted.
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88
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Méndez-Samperio P. Diagnosis of Tuberculosis in HIV Co-infected Individuals: Current Status, Challenges and Opportunities for the Future. Scand J Immunol 2017; 86:76-82. [PMID: 28513865 DOI: 10.1111/sji.12567] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 05/07/2017] [Indexed: 02/03/2023]
Abstract
Tuberculosis (TB) remains one of the most important causes of death among people co-infected with human immunodeficiency virus (HIV). The diagnosis of TB remains challenging in HIV co-infected individuals, due to a high frequency of smear-negative disease and high rates of extrapulmonary TB. Accurate, ease of use and rapid diagnosis of active TB are critical to the World Health Organization (WHO) End TB Strategy by 2050. Traditional laboratory techniques do not provide rapid and accurate results to effectively manage HIV co-infected patients. Over the last decade, molecular methods have provided significant steps in the fight against TB. However, many HIV co-infected patients do not have access to these molecular diagnostic tests. Given the costs closely related with confirming a TB diagnosis in HIV patients, an overtreatment for TB is used in this patient population. Nowadays, an estimated US $8 billion a year is required to provide TB treatment, which is very high compared with making an important strategy to improve the current diagnostic tests. This review focuses on current advances in diagnosing active TB with an emphasis on the diagnosis of HIV-associated TB. Also discussed are the main challenges that need to be overcome for improving an adequate initial diagnosis of active TB in HIV-positive patients.
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Affiliation(s)
- P Méndez-Samperio
- Departamento de Inmunología, Escuela Nacional de Ciencias Biológicas, IPN, México, México
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Meyer AJ, Atuheire C, Worodria W, Kizito S, Katamba A, Sanyu I, Andama A, Ayakaka I, Cattamanchi A, Bwanga F, Huang L, Davis JL. Sputum quality and diagnostic performance of GeneXpert MTB/RIF among smear-negative adults with presumed tuberculosis in Uganda. PLoS One 2017; 12:e0180572. [PMID: 28686705 PMCID: PMC5501569 DOI: 10.1371/journal.pone.0180572] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 06/16/2017] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Introduction of GeneXpert MTB/RIF (Xpert) assay has constituted a major breakthrough for tuberculosis (TB) diagnostics. Several patient factors may influence diagnostic performance of Xpert including sputum quality. OBJECTIVE We carried out a prospective, observational, cross-sectional study to determine the effect of sputum quality on diagnostic performance of Xpert among presumed TB patients in Uganda. METHODS We collected clinical and demographic information and two sputum samples from participants. Staff recorded sputum quality and performed LED fluorescence microscopy and mycobacterial culture on each sample. If both smear examinations were negative, Xpert testing was performed. We calculated diagnostic yield, sensitivity, specificity, and other indicators for Xpert for each stratum of sputum quality in reference to a standard of mycobacterial culture. RESULTS Patients with salivary sputum showed a trend towards a substantially higher proportion of samples that were Xpert-positive (54/286, 19%, 95% CI 15-24) compared with those with all other sputum sample types (221/1496, 15%, 95% CI 13-17). Blood-stained sputum produced the lowest sensitivity (28%; 95% CI 12-49) and salivary sputum the highest (66%; 95% CI 53-77). Specificity didn't vary meaningfully by sample types. Salivary sputum was significantly more sensitive than mucoid sputum (+13%, 95% CI +1 to +26), while blood-stained sputum was significantly less sensitive (-24%, 95% CI -42 to -5). CONCLUSIONS Our findings demonstrate the need to exercise caution in collecting sputum for Xpert and in interpreting results because sputum quality may impact test yield and sensitivity. In particular, it may be wise to pursue additional testing should blood-stained sputum test negative while salivary sputum should be readily accepted for Xpert testing given its higher sensitivity and potentially higher yield than other sample types. These findings challenge conventional recommendations against collecting salivary sputum for TB diagnosis and could inform new standards for sputum quality.
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Affiliation(s)
- Amanda J. Meyer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
| | - Collins Atuheire
- Department of Health Sciences & Special Education, Africa Renewal University, Kampala, Uganda
| | - William Worodria
- Department of Medicine, Mulago Hospital, Makerere University, Kampala, Uganda
| | - Samuel Kizito
- Clinical Epidemiology Unit, Makerere University, Kampala, Uganda
| | - Achilles Katamba
- Clinical Epidemiology Unit, Makerere University, Kampala, Uganda
| | - Ingvar Sanyu
- Infectious Diseases Research Collaboration, Mulago Hospital, Kampala, Uganda
| | - Alfred Andama
- Department of Medicine, Mulago Hospital, Makerere University, Kampala, Uganda
- Infectious Diseases Research Collaboration, Mulago Hospital, Kampala, Uganda
| | - Irene Ayakaka
- Infectious Diseases Research Collaboration, Mulago Hospital, Kampala, Uganda
| | - Adithya Cattamanchi
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Freddie Bwanga
- Department of Microbiology, Makerere University, Kampala, Uganda
| | - Laurence Huang
- Division of Pulmonary and Critical Care Medicine, University of California San Francisco, San Francisco, California, United States of America
- Division of HIV, Infectious Diseases, and Global Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - J. Lucian Davis
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America
- Pulmonary, Critical Care, and Sleep Medicine Section, Yale School of Medicine, New Haven, Connecticut, United States of America
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Evaluation of the MTBDRplus 2.0 assay for the detection of multidrug resistance among persons with presumptive pulmonary TB in China. Sci Rep 2017; 7:3364. [PMID: 28611407 PMCID: PMC5469733 DOI: 10.1038/s41598-017-03473-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 04/28/2017] [Indexed: 11/08/2022] Open
Abstract
We have conducted a multicenter study of the diagnostic accuracy of the MTBDRplus 2.0 assay in compared with conventional and molecular reference standard in four tuberculosis (TB)-specialized hospitals of China. A total of 5038 patients were enrolled in this study. The overall sensitivity of the assay for the diagnosis of TB was 92.7% [1723/1858, 95% confidence interval (95% CI): 91.5-93.9]. In smear-positive/culture-positive cases the sensitivity was 97.7% (995/1018, 95% CI: 96.6-98.6), whereas in smear-negative/culture-positive cases it was 86.7% (728/840, 95% CI: 84.2-88.9). The agreement rate between MTBDRplus 2.0 and Xpert MTB/RIF was 97.7% (1015/1039, 95% CI: 96.6-98.5) for smear-positive cases and 97.0% (3682/3794, 95% CI: 96.5-97.6) for smear-negative cases. As compared with phenotypic drug susceptibility testing, the MTBDRplus 2.0 correctly identified 298 of 315 patients (94.6%, 95% CI: 91.5-96.8) with rifampicin-resistance. As noted previously, isoniazid resistance is associated with many different mutations and consequently the sensitivity compared to phenotypic testing was lower (81.0%, 95% CI: 76.8-84.7). In conclusion, this assay is a rapid, accurate test in terms of increased sensitivity for detecting smear-negative TB patients, as well as an alternative for detecting both RIF and INH resistance in persons with presumptive TB, whereas the absence of a mutation in the specimens must be interpreted cautiously.
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91
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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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Chikaonda T, Nguluwe N, Barnett B, Gokhale RH, Krysiak R, Thengolose I, Rosenberg NE, Stanley C, Mpunga J, Hoffman IF, Hosseinipour M, Scott L, Stevens W. Performance of Xpert ® MTB/RIF among tuberculosis outpatients in Lilongwe, Malawi. Afr J Lab Med 2017; 6:464. [PMID: 28879160 PMCID: PMC5516918 DOI: 10.4102/ajlm.v6i2.464] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 10/13/2016] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Xpert® MTB/RIF is a molecular test for the detection of Mycobacterium tuberculosis and rifampicin resistance. It is considered to be a great advance over smear microscopy and culture. However, there is very little information regarding the performance characteristics of Xpert MTB/RIF in Malawi. OBJECTIVE We aimed to evaluate the performance of Xpert MTB/RIF in a Malawian setting. METHODS Stored sputum pellets were processed on Xpert MTB/RIF between June 2012 and May 2014. Results were compared to mycobacteria growth indicator tube and Löwenstein-Jensen cultures, LED fluorescent microscopy and GenoType® MTBDRplus assay. Rifampicin resistance was confirmed by DNA sequencing. RESULTS Of the 348 specimens with valid Xpert MTB/RIF results, 129/348 (37%) were smear-positive and 198/348 (57%) were culture-positive. Xpert MTB/RIF demonstrated a sensitivity of 93.8% (95% CI 89.4% - 96.8%) and specificity of 97.4% (95% CI 93.5% - 99.3%), with a positive predictive value of 97.8% (95% CI 94.6% - 99.4%) and a negative predictive value of 92.6% (95% CI 87.4% - 96.1%). Xpert MTB/RIF correctly identified 185/186 (99.5%) rifampicin-sensitive and 2/2 (100%) rifampicin-resistant M. tuberculosis strains. Mutations were not detected by sequencing in one isolate which was rifampicin resistant on Xpert MTB/RIF but sensitive on MTBDRplus. Four non-tuberculous mycobacteria grew from four smear-negative specimens, namely, M. avium (n = 1) and M. intracellulare (n = 3). No cross-reactivity was observed with any of the non-tuberculous mycobacteria when using Xpert MTB/RIF. CONCLUSION When fully implemented, Xpert MTB/RIF may have an impact on patient care in Malawi. The increased diagnostic yield of Xpert MTB/RIF over smear microscopy can increase laboratory-confirmed tuberculosis detection and ensure that treatment is given to appropriate individuals or groups.
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Affiliation(s)
- Tarsizio Chikaonda
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
- University of North Carolina Project, Lilongwe, Malawi
| | | | - Brian Barnett
- University of North Carolina Project, Lilongwe, Malawi
| | | | | | | | | | | | - James Mpunga
- Malawi National Tuberculosis Programme, Lilongwe, Malawi
| | - Irving F. Hoffman
- University of North Carolina Project, Lilongwe, Malawi
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Mina Hosseinipour
- University of North Carolina Project, Lilongwe, Malawi
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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93
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Chikaonda T, Ketseoglou I, Nguluwe N, Krysiak R, Thengolose I, Nyakwawa F, Rosenberg NE, Stanley C, Mpunga J, Hoffman IF, Papathanasopoulos MA, Hosseinipour M, Scott L, Stevens W. Molecular characterisation of rifampicin-resistant Mycobacterium tuberculosis strains from Malawi. Afr J Lab Med 2017; 6:463. [PMID: 28879159 PMCID: PMC5523914 DOI: 10.4102/ajlm.v6i2.463] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 10/05/2016] [Indexed: 12/02/2022] Open
Abstract
Background Availability and access to the detection of resistance to anti-tuberculosis drugs remains a significant challenge in Malawi due to limited diagnostic services. The Xpert® MTB/RIF can detect Mycobacterium tuberculosis and resistance to rifampicin in a single, rapid assay. Rifampicin-resistant M. tuberculosis has not been well studied in Malawi. Objectives We aimed to determine mutations in the rifampicin resistance determining region (RRDR) of the rpoB gene of M. tuberculosis strains which were defined as resistant to rifampicin by the Xpert MTB/RIF assay. Methods Rifampicin-resistant isolates from 43 adult patients (≥ 18 years) from various districts of Malawi were characterised for mutations in the RRDR (codons 507–533) of the rpoB gene by DNA sequencing. Results Mutations were found in 37/43 (86%) of the resistant isolates in codons 511, 512, 513, 516, 522, 526 and 531. The most common mutations were in codons 526 (38%), 531 (29.7%) and 516 (16.2%). Mutations were not found in 6/43 (14%) of the resistant isolates. No novel rpoB mutations other than those previously described were found among the rifampicin-resistant M. tuberculosis complex strains. Conclusion This study is the first to characterise rifampicin resistance in Malawi. The chain-termination DNA sequencing employed in this study is a standard method for the determination of nucleotide sequences and can be used to confirm rifampicin resistance obtained using other assays, including the Xpert MTB/RIF. Further molecular cluster analysis, such as spoligotyping and DNA finger printing, is still required to determine transmission dynamics and the epidemiological link of the mutated strains.
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Affiliation(s)
- Tarsizio Chikaonda
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa.,UNC Project, Lilongwe, Malawi
| | - Irene Ketseoglou
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | | | | | | | - Felix Nyakwawa
- Malawi National Tuberculosis Programme, Lilongwe, Malawi
| | | | | | - James Mpunga
- Malawi National Tuberculosis Programme, Lilongwe, Malawi
| | - Irving F Hoffman
- UNC Project, Lilongwe, Malawi.,University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Maria A Papathanasopoulos
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Mina Hosseinipour
- UNC Project, Lilongwe, Malawi.,University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | - Lesley Scott
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
| | - Wendy Stevens
- Department of Molecular Medicine and Haematology, Faculty of Health Sciences, School of Pathology, University of the Witwatersrand, Johannesburg, South Africa
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94
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Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring. Proc Natl Acad Sci U S A 2017; 114:3969-3974. [PMID: 28348223 DOI: 10.1073/pnas.1621360114] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Tuberculosis (TB) is a major global health threat, resulting in an urgent unmet need for a rapid, non-sputum-based quantitative test to detect active Mycobacterium tuberculosis (Mtb) infections in clinically diverse populations and quickly assess Mtb treatment responses for emerging drug-resistant strains. We have identified Mtb-specific peptide fragments and developed a method to rapidly quantify their serum concentrations, using antibody-labeled and energy-focusing porous discoidal silicon nanoparticles (nanodisks) and high-throughput mass spectrometry (MS) to enhance sensitivity and specificity. NanoDisk-MS diagnosed active Mtb cases with high sensitivity and specificity in a case-control study with cohorts reflecting the complexity of clinical practice. Similar robust sensitivities were obtained for cases of culture-positive pulmonary TB (PTB; 91.3%) and extrapulmonary TB (EPTB; 92.3%), and the sensitivities obtained for culture-negative PTB (82.4%) and EPTB (75.0%) in HIV-positive patients significantly outperformed those reported for other available assays. NanoDisk-MS also exhibited high specificity (87.1-100%) in both healthy and high-risk groups. Absolute quantification of serum Mtb antigen concentration was informative in assessing responses to antimycobacterial treatment. Thus, a NanoDisk-MS assay approach could significantly improve the diagnosis and management of active TB cases, and perhaps other infectious diseases as well.
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95
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Naidoo P, Dunbar R, Caldwell J, Lombard C, Beyers N. Has universal screening with Xpert® MTB/RIF increased the proportion of multidrug-resistant tuberculosis cases diagnosed in a routine operational setting? PLoS One 2017; 12:e0172143. [PMID: 28199375 PMCID: PMC5310774 DOI: 10.1371/journal.pone.0172143] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 01/31/2017] [Indexed: 01/30/2023] Open
Abstract
SETTING Primary health services in Cape Town, South Africa where the introduction of Xpert® MTB/RIF (Xpert) enabled simultaneous screening for tuberculosis (TB) and drug susceptibility in all presumptive cases. STUDY AIM To compare the proportion of TB cases with drug susceptibility tests undertaken and multidrug-resistant tuberculosis (MDR-TB) diagnosed pre-treatment and during the course of 1st line treatment in the previous smear/culture and the newly introduced Xpert-based algorithms. METHODS TB cases identified in a previous stepped-wedge study of TB yield in five sub-districts over seven one-month time-points prior to, during and after the introduction of the Xpert-based algorithm were analysed. We used a combination of patient identifiers to identify all drug susceptibility tests undertaken from electronic laboratory records. Differences in the proportions of DST undertaken and MDR-TB cases diagnosed between algorithms were estimated using a binomial regression model. RESULTS Pre-treatment, the probability of having a DST undertaken (RR = 1.82)(p<0.001) and being diagnosed with MDR-TB (RR = 1.42)(p<0.001) was higher in the Xpert-based algorithm than in the smear/culture-based algorithm. For cases evaluated during the course of 1st-line TB treatment, there was no significant difference in the proportion with DST undertaken (RR = 1.02)(p = 0.848) or MDR-TB diagnosed (RR = 1.12)(p = 0.678) between algorithms. CONCLUSION Universal screening for drug susceptibility in all presumptive TB cases in the Xpert-based algorithm resulted in a higher overall proportion of MDR-TB cases being diagnosed and is an important strategy in reducing transmission. The previous strategy of only screening new TB cases when 1st line treatment failed did not compensate for cases missed pre-treatment.
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Affiliation(s)
- Pren Naidoo
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Rory Dunbar
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
| | | | - Carl Lombard
- Biostatistics Unit, South African Medical Research Council, Cape Town, South Africa
| | - Nulda Beyers
- Desmond Tutu TB Centre, Department of Paediatrics and Child Health, Faculty of Medicine and Health Sciences, Stellenbosch University, Stellenbosch, South Africa
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96
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Das S, Shibib DR, Vernon MO. The new frontier of diagnostics: Molecular assays and their role in infection prevention and control. Am J Infect Control 2017; 45:158-169. [PMID: 28159066 PMCID: PMC7115290 DOI: 10.1016/j.ajic.2016.08.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/19/2016] [Accepted: 08/19/2016] [Indexed: 01/05/2023]
Abstract
Recent advances in technology over the last decade have propelled the microbiology laboratory into a pivotal role in infection prevention and control. The rapid adaptation of molecular technologies to the field of clinical microbiology now greatly influences infectious disease management and significantly impacts infection control practices. This review discusses recent developments in molecular techniques in the diagnosis of infectious diseases. It describes the basic concepts of molecular assays, discusses their advantages and limitations, and characterizes currently available commercial assays with respect to cost, interpretive requirements, and clinical utility.
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97
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Su KY, Yan BS, Chiu HC, Yu CJ, Chang SY, Jou R, Liu JL, Hsueh PR, Yu SL. Rapid Sputum Multiplex Detection of the M. tuberculosis Complex (MTBC) and Resistance Mutations for Eight Antibiotics by Nucleotide MALDI-TOF MS. Sci Rep 2017; 7:41486. [PMID: 28134321 PMCID: PMC5278408 DOI: 10.1038/srep41486] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 12/21/2016] [Indexed: 01/29/2023] Open
Abstract
The increasing incidence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) Mycobacterium tuberculosis (MTB) adds further urgency for rapid and multiplex molecular testing to identify the MTB complex and drug susceptibility directly from sputum for disease control. A nucleotide matrix-assisted-laser-desorption-ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based assay was developed to identify MTB (MTBID panel) and 45 chromosomal mutations for resistance to eight antibiotics (MTBDR panel). We conducted a 300 case trial from outpatients to evaluate this platform. An MTBID panel specifically identified MTB with as few as 10 chromosome DNA copies. The panel was 100% consistent with an acid-fast stain and culture for MTB, nontuberculous mycobacteria, and non-mycobacteria bacteria. The MTBDR panel was validated using 20 known MDR-MTB isolates. In a 64-case double-blind clinical isolates test, the sensitivity and specificity were 83% and 100%, respectively. In a 300-case raw sputum trial, the MTB identification sensitivity in smear-negative cases using MALDI-TOF MS was better than the COBAS assay (61.9% vs. 46.6%). Importantly, the failure rate of MALDI-TOF MS was better than COBAS (11.3% vs. 26.3%). To the best of our knowledge, the test described herein is the only multiplex test that predicts resistance for up to eight antibiotics with both sensitivity and flexibility.
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Affiliation(s)
- Kang-Yi Su
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Bo-Shiun Yan
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hao-Chieh Chiu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chong-Jen Yu
- Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - So-Yi Chang
- Institute of Biochemistry and Molecular Biology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ruwen Jou
- Centers for Disease Control, Taipei, Taiwan
| | - Jia-Long Liu
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Po-Ren Hsueh
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Internal Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Sung-Liang Yu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.,Department of Pathology and Graduate Institute of Pathology, College of Medicine, National Taiwan University, Taipei, Taiwan.,Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan.,Institute of Medical Device and Imaging, College of Medicine, National Taiwan University, Taipei, Taiwan
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98
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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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Ho J, Marks GB. Predicting tuberculosis without knowing test specificity: Authors' reply. THE LANCET. INFECTIOUS DISEASES 2016; 16:1222. [PMID: 27788977 DOI: 10.1016/s1473-3099(16)30389-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Accepted: 09/21/2016] [Indexed: 11/17/2022]
Affiliation(s)
- Jennifer Ho
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, Australia; Centre for Research Excellence in Tuberculosis (TB-CRE), University of Sydney, Sydney, Australia.
| | - Guy B Marks
- Woolcock Institute of Medical Research, University of Sydney, Sydney, Australia; South Western Sydney Clinical School, University of New South Wales, Sydney, Australia; Centre for Research Excellence in Tuberculosis (TB-CRE), University of Sydney, Sydney, Australia
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Abstract
BACKGROUND Tuberculosis (TB) remains a major contributor to morbidity and mortality in HIV-positive individuals, causing 1.1 million incident cases and 0.32 million deaths in 2012. Diagnosis of TB is particularly challenging in HIV-coinfected individuals, due to a high frequency of smear-negative disease, atypical presentations, and extrapulmonary TB. OBJECTIVE The aim of this article was to review the current literature on molecular diagnostics for TB with an emphasis on the performance of these diagnostic tests in the HIV-positive population. METHODS We searched the PubMed database using at least one of the terms TB, HIV, diagnostics, Xpert MTB/RIF, nucleic acid amplification tests, drug susceptibility testing, RNA transcription, and drew on World Health Organization publications. FINDINGS With increased focus on reducing TB prevalence worldwide, a new set of tools for diagnosing the disease have emerged. Molecular tools such as Xpert MTB/RIF and line-probe assays are now in use or are being rolled out in many regions. The diagnostic performance of these and other molecular assays are discussed here as they pertain to the HIV-positive population. CONCLUSIONS Molecular diagnostics offer a useful addition and at times, alternative, to traditional culture methods for the diagnosis of TB. However, most of these tests suffer from decreased accuracy in the HIV-positive population.
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