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Rajendran P, Kumar MP, Thiruvengadam K, Sreenivasan P, Veeraraghavan T, Ramalingam R, Hasini S, Dhanaraju T, Kuppamuthu R, Shanmugam S, Frederick A, Padmapriyadarsini C. Characterization of probes associated with rifampicin resistance in M.tuberculosis detected by GenXpert from a national reference laboratory at Chennai. Tuberculosis (Edinb) 2022; 133:102182. [DOI: 10.1016/j.tube.2022.102182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 01/29/2022] [Accepted: 02/06/2022] [Indexed: 11/29/2022]
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Bristow CC, Mehta SR, Hoenigl M, Little SJ. The Performance of Pooled 3 Anatomic Site Testing for Chlamydia trachomatis and Neisseria gonorrhoeae Among Men Who Have Sex With Men and Transgender Women. Sex Transm Dis 2021; 48:733-737. [PMID: 34110736 PMCID: PMC8435040 DOI: 10.1097/olq.0000000000001411] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Although molecular testing for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) is highly sensitive, the cost can be prohibitive. Those high costs are amplified when the recommended screening approach is used, which requires separate testing of specimens from 3 anatomic sites (rectal, pharyngeal and urogenital). Although individual molecular testing is standard of care, pooled testing may offer a cost-saving alternative. METHODS Using the Xpert® CT/NG assay (Cepheid, Sunnyvale, CA) we tested urine, rectal and pharyngeal swabs for CT and NG in a high-risk cohort of participants assigned male at birth who reported sex with other persons who were assigned male at birth. Remnant specimens (0.34 mL from each anatomic site) were combined to perform a single 'pooled' test. We calculated positive and negative percent agreement between the pooled testing results with standard of care Xpert CT/NG test results as the reference. RESULTS We conducted 644 pooled tests. Of those, 598 (92.3%) gave CT and NG results. The CT-positive and -negative percent agreement were 90.1% (95% confidence interval [CI], 80.7-95.9%) and 99.2% (98.1-99.8%), respectively. The NG-positive and -negative percent agreement were 96.2% (95% CI, 86.8-99.5%) and 99.8% (95% CI, 99.0-100%), respectively. Pooled testing identified 4 CT and 1 NG infections that were negative at all anatomic sites by individual testing. CONCLUSIONS Three-site pooled CT and NG testing performs similarly to single anatomic site testing among tests providing a valid result. Future cost analyses should evaluate the cost effectiveness of pooled 3-site testing to determine if such a strategy improves the feasibility and accessibility of molecular sexually transmitted infection testing.
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Affiliation(s)
- Claire C Bristow
- Division of Infectious Disease and Global Public Health, Department of Medicine, University of California San Diego
| | - Sanjay R. Mehta
- Division of Infectious Disease and Global Public Health, Department of Medicine, University of California San Diego
- Department of Medicine and Pathology, San Diego Veterans Affairs Medical Center, San Diego, CA
| | - Martin Hoenigl
- Division of Infectious Disease and Global Public Health, Department of Medicine, University of California San Diego
| | - Susan J. Little
- Division of Infectious Disease and Global Public Health, Department of Medicine, University of California San Diego
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Brito GMXD, Mafort TT, Ribeiro-Alves M, Reis LVTD, Leung J, Leão RS, Rufino R, Rodrigues LS. Diagnostic performance of the Xpert MTB/RIF assay in BAL fluid samples from patients under clinical suspicion of pulmonary tuberculosis: a tertiary care experience in a high-tuberculosis-burden area. ACTA ACUST UNITED AC 2021; 47:e20200581. [PMID: 34008762 PMCID: PMC8332835 DOI: 10.36416/1806-3756/e20200581] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Accepted: 03/08/2021] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To assess the diagnostic performance of the Xpert MTB/RIF assay, a rapid molecular test for tuberculosis, comparing it with that of AFB staining and culture, in BAL fluid (BALF) samples from patients with clinically suspected pulmonary tuberculosis (PTB) who are sputum smear-negative or produce sputum samples of insufficient quantity. METHODS This was a retrospective study of 140 cases of suspected PTB in patients who were smear-negative or produced insufficient sputum samples and were evaluated at a tertiary teaching hospital in the city of Rio de Janeiro, Brazil. All of the patients underwent fiberoptic bronchoscopy with BAL. The BALF specimens were evaluated by AFB staining, mycobacterial culture, and the Xpert MTB/RIF assay. RESULTS Among the 140 patients, results for all three microbiological examinations were available for 73 (52.1%), of whom 22 tested positive on culture, 17 tested positive on AFB staining, and 20 tested positive on the Xpert MTB/RIF assay. The sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for AFB staining were 68.1%, 96.1%, 88.2%, 87.5%, and 87.6%, respectively, compared with 81.8%, 96.1%, 90.0%, 92.4%, and 91.8%, respectively, for the Xpert MTB/RIF assay. The agreement between AFB staining and culture was 82.3% (kappa = 0.46; p < 0.0001), whereas that between the Xpert MTB/RIF assay and culture was 91.8% (kappa = 0.8; p < 0.0001). CONCLUSIONS In BALF samples, the Xpert MTB/RIF assay performs better than do traditional methods, providing a reliable alternative to sputum analysis in suspected cases of PTB. However, the rate of discordant results merits careful consideration.
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Affiliation(s)
- Guilherme Machado Xavier de Brito
- . Laboratório de Imunopatologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
| | - Thiago Thomaz Mafort
- . Disciplina de Pneumologia e Tisiologia, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
| | - Marcelo Ribeiro-Alves
- . Laboratório de Pesquisas Clínicas em DST/AIDS, Instituto Nacional de Infectologia Evandro Chagas, Fundação Oswaldo Cruz, Rio de Janeiro, Rio de Janeiro (RJ) Brasil
| | - Larissa Vieira Tavares Dos Reis
- . Disciplina de Pneumologia e Tisiologia, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
| | - Janaína Leung
- . Disciplina de Pneumologia e Tisiologia, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
| | - Robson Souza Leão
- . Departamento de Microbiologia, Imunologia e Parasitologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
| | - Rogério Rufino
- . Disciplina de Pneumologia e Tisiologia, Hospital Universitário Pedro Ernesto, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
| | - Luciana Silva Rodrigues
- . Laboratório de Imunopatologia, Faculdade de Ciências Médicas, Universidade do Estado do Rio de Janeiro - UERJ - Rio de Janeiro (RJ) Brasil
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Abstract
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Prompt and accurate diagnosis of drug resistance is essential for optimal treatment of
drug-resistant tuberculosis. However, only 20% of the more than half a million patients eligible for
the treatment of MDR-TB/RR-TB receive an appropriate drug regimen. Drug-resistant TB regimens
must include a sufficient number of effective medications, a significant challenge for clinicians
worldwide, as most are forced to make therapeutic decisions without any, or very little information
on drug susceptibility testing. Although phenotypic DST is still commonly regarded as the
gold standard for determining M. tuberculosis susceptibility to antituberculosis drugs, it has several
limitations, mainly its prolonged turnaround time. Molecular methods based on M. tuberculosis genomic
DNA sequencing have been developed during the past two decades, to identify the most
common mutations involved in drug resistance. The Xpert
®
MTB/RIF is a real-time polymerase
chain reaction that offers results in less than two hours and has an overall sensitivity for rifampin resistance
of 96% and 98% specificity. Line probe assays (LPAs) are commercial DNA strip-based
tests for detecting the most frequent mutations responsible for resistance to rifampin, isoniazid, fluoroquinolones,
and second-line injectable drugs.
:
Discrepancies between phenotypic and genotyping methods are a problem that the clinician will
face in everyday practice. However, any resistance result (with any type of test) in a person with
risk factors for harboring resistant microorganisms should be considered appropriate while the results
of complementary tests are available.
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Affiliation(s)
- Rafael Laniado-Laborín
- Clinica y Laboratorio de Tuberculosis, Hospital General Tijuana, ISESALUD, Mexicali, Mexico
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García JI, Mambuque E, Nguenha D, Vilanculo F, Sacoor C, Sequera VG, Fernández-Quevedo M, Pierre MLL, Chiconela H, Faife LA, Respeito D, Saavedra B, Nhampossa T, López-Varela E, Garcia-Basteiro AL. Mortality and risk of tuberculosis among people living with HIV in whom TB was initially ruled out. Sci Rep 2020; 10:15442. [PMID: 32963296 PMCID: PMC7509810 DOI: 10.1038/s41598-020-71784-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 07/31/2020] [Indexed: 12/12/2022] Open
Abstract
Tuberculosis (TB) misdiagnosis remains a public health concern, especially among people living with HIV (PLHIV), given the high mortality associated with missed TB diagnoses. The main objective of this study was to describe the all-cause mortality, TB incidence rates and their associated risk factors in a cohort of PLHIV with presumptive TB in whom TB was initially ruled out. We retrospectively followed a cohort of PLHIV with presumptive TB over a 2 year-period in a rural district in Southern Mozambique. During the study period 382 PLHIV were followed-up. Mortality rate was 6.8/100 person-years (PYs) (95% CI 5.2-9.2) and TB incidence rate was 5.4/100 PYs (95% CI 3.9-7.5). Thirty-six percent of deaths and 43% of TB incident cases occurred in the first 12 months of the follow up. Mortality and TB incidence rates in the 2-year period after TB was initially ruled out was very high. The TB diagnostic work-up and linkage to HIV care should be strengthened to decrease TB burden and all-cause mortality among PLHIV with presumptive TB.
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Affiliation(s)
- Juan Ignacio García
- TB Group, Population Health Program, Texas Biomedical Research Institute, San Antonio, TX, USA
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Edson Mambuque
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
| | - Dinis Nguenha
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
| | | | - Charfudin Sacoor
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
| | | | | | | | - Helio Chiconela
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- Manhiça District Hospital, Ministry of Health, National Tuberculosis Control Program, Maputo, Mozambique
| | - Luis A Faife
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- Manhiça District Hospital, Ministry of Health, National Tuberculosis Control Program, Maputo, Mozambique
| | - Durval Respeito
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- Manhiça District Hospital, Ministry of Health, National Tuberculosis Control Program, Maputo, Mozambique
| | - Belén Saavedra
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Tacilta Nhampossa
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- Instituto Nacional de Saúde, Ministério de Saúde, Maputo, Mozambique
| | - Elisa López-Varela
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
- Desmond Tutu TB center, Stellenbosch University, Cape Town, South Africa
| | - Alberto L Garcia-Basteiro
- Centro de Investigação em Saude de Manhiça (CISM), Maputo, Mozambique.
- ISGlobal, Hospital Clínic - Universitat de Barcelona, Barcelona, Spain.
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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Bahr NC, Meintjes G, Boulware DR. Inadequate diagnostics: the case to move beyond the bacilli for detection of meningitis due to Mycobacterium tuberculosis. J Med Microbiol 2019; 68:755-760. [PMID: 30994435 PMCID: PMC7176281 DOI: 10.1099/jmm.0.000975] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Tuberculosis (TB) meningitis is extremely difficult to diagnose due to its pauci-bacillary disease nature and new techniques are needed. Improved test sensitivity would allow for greater clinician confidence in diagnostic testing and has the potential to improve patient outcomes. Traditional microbiologic and molecular tests for TB meningitis focus on detection of TB bacilli and are inadequate. Smear microscopy is rapid but only ~10-15 % sensitive. Culture has 50-60 % sensitivity but is slow. Xpert MTB/Rif Ultra is a rapid, automated PCR-based assay with ~70 % sensitivity versus clinical case definition. Thus, even the best current testing may miss up to 30 % of cases. Clinicians are often left to treat empirically with prolonged regimens with significant side effects or risk a missed case that would result in death. Rather than relying strictly on microbiologic or molecular testing to diagnose TB meningitis, we propose that testing of CSF for biomarkers of host response may have an adjunctive role to play in improving the diagnosis of TB meningitis.
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Affiliation(s)
- Nathan C. Bahr
- University of Kansas, Kansas City, KS, USA
- *Correspondence: Nathan C. Bahr,
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Silva TMD, Soares VM, Ramos MG, Santos AD. Accuracy of a rapid molecular test for tuberculosis in sputum samples, bronchoalveolar lavage fluid, and tracheal aspirate obtained from patients with suspected pulmonary tuberculosis at a tertiary referral hospital. ACTA ACUST UNITED AC 2019; 45:e20170451. [PMID: 30864607 PMCID: PMC6733743 DOI: 10.1590/1806-3713/e20170451] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 08/12/2018] [Indexed: 12/03/2022]
Abstract
Tuberculosis continues to be a major public health problem worldwide. The aim of the present study was to evaluate the accuracy of the Xpert MTB/RIF rapid molecular test for tuberculosis, using pulmonary samples obtained from patients treated at the Júlia Kubitschek Hospital, which is operated by the Hospital Foundation of the State of Minas Gerais, in the city of Belo Horizonte, Brazil. This was a retrospective study comparing the Xpert MTB/RIF test results with those of standard culture for Mycobacterium tuberculosis and phenotypic susceptibility tests. Although the Xpert MTB/RIF test showed high accuracy for the detection of M. tuberculosis and its resistance to rifampin, attention must be given to the clinical status of the patient, in relation to the test results, as well as to the limitations of molecular tests.
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Affiliation(s)
- Tatiane Maria da Silva
- . Faculdade de Biomedicina, Universidade da Fundação Mineira de Educação e Cultura - FUMEC - Belo Horizonte (MG) Brasil
| | - Valéria Martins Soares
- . Setor de Microbiologia, Laboratório do Hospital Júlia Kubitschek, Fundação Hospitalar do Estado de Minas Gerais - FHEMIG - Belo Horizonte (MG) Brasil
| | - Mariana Gontijo Ramos
- . Faculdade de Biomedicina, Universidade da Fundação Mineira de Educação e Cultura - FUMEC - Belo Horizonte (MG) Brasil
| | - Adriana Dos Santos
- . Faculdade de Biomedicina, Universidade da Fundação Mineira de Educação e Cultura - FUMEC - Belo Horizonte (MG) Brasil
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Osorio L, Garcia JA, Parra LG, Garcia V, Torres L, Degroote S, Ridde V. A scoping review on the field validation and implementation of rapid diagnostic tests for vector-borne and other infectious diseases of poverty in urban areas. Infect Dis Poverty 2018; 7:87. [PMID: 30173662 PMCID: PMC6120097 DOI: 10.1186/s40249-018-0474-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 08/01/2018] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Health personnel face challenges in diagnosing vector-borne and other diseases of poverty in urban settings. There is a need to know what rapid diagnostic technologies are available, have been properly assessed, and are being implemented to improve control of these diseases in the urban context. This paper characterizes evidence on the field validation and implementation in urban areas of rapid diagnostics for vector-borne diseases and other diseases of poverty. MAIN BODY A scoping review was conducted. Peer-reviewed and grey literature were searched using terms describing the targeted infectious diseases, diagnostics evaluations, rapid tests, and urban setting. The review was limited to studies published between 2000 and 2016 in English, Spanish, French, and Portuguese. Inclusion and exclusion criteria were refined post hoc to identify relevant literature regardless of study design and geography. A total of 179 documents of the 7806 initially screened were included in the analysis. Malaria (n = 100) and tuberculosis (n = 47) accounted for the majority of studies that reported diagnostics performance, impact, and implementation outcomes. Fewer studies, assessing mainly performance, were identified for visceral leishmaniasis (n = 9), filariasis and leptospirosis (each n = 5), enteric fever and schistosomiasis (each n = 3), dengue and leprosy (each n = 2), and Chagas disease, human African trypanosomiasis, and cholera (each n = 1). Reported sensitivity of rapid tests was variable depending on several factors. Overall, specificities were high (> 80%), except for schistosomiasis and cholera. Impact and implementation outcomes, mainly acceptability and cost, followed by adoption, feasibility, and sustainability of rapid tests are being evaluated in the field. Challenges to implementing rapid tests range from cultural to technical and administrative issues. CONCLUSIONS Rapid diagnostic tests for vector-borne and other diseases of poverty are being used in the urban context with demonstrated impact on case detection. However, most evidence comes from malaria rapid diagnostics, with variable results. While rapid tests for tuberculosis and visceral leishmaniasis require further implementation studies, more evidence on performance of current tests or development of new alternatives is needed for dengue, Chagas disease, filariasis, leptospirosis, enteric fever, human African trypanosomiasis, schistosomiasis and cholera.
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Affiliation(s)
- Lyda Osorio
- Epidemiology and Population Health Research Group, School of Public Health, Universidad del Valle, Calle 4B No. 36-00 Edif 118 Escuela de Salud Pública, Universidad del Valle Campus San Fernando, Cali, Colombia
| | - Jonny Alejandro Garcia
- Epidemiology and Population Health Research Group, School of Public Health, Universidad del Valle, Calle 4B No. 36-00 Edif 118 Escuela de Salud Pública, Universidad del Valle Campus San Fernando, Cali, Colombia
- School of Medicine, Universidad del Valle, Cali, Colombia
| | - Luis Gabriel Parra
- Epidemiology and Population Health Research Group, School of Public Health, Universidad del Valle, Calle 4B No. 36-00 Edif 118 Escuela de Salud Pública, Universidad del Valle Campus San Fernando, Cali, Colombia
- School of Medicine, Universidad del Valle, Cali, Colombia
| | - Victor Garcia
- Epidemiology and Population Health Research Group, School of Public Health, Universidad del Valle, Calle 4B No. 36-00 Edif 118 Escuela de Salud Pública, Universidad del Valle Campus San Fernando, Cali, Colombia
| | - Laura Torres
- Epidemiology and Population Health Research Group, School of Public Health, Universidad del Valle, Calle 4B No. 36-00 Edif 118 Escuela de Salud Pública, Universidad del Valle Campus San Fernando, Cali, Colombia
| | - Stéphanie Degroote
- University of Montreal Public Health Research Institute (IRSPUM), Montreal, Canada
| | - Valéry Ridde
- University of Montreal Public Health Research Institute (IRSPUM), Montreal, Canada
- French Institute for Research on Sustainable Development (IRD), Paris Descartes University, Population and Development Center (CEPED), Université Paris Sorbonne Cité, National Institute of Health and Medical Research (INSERM), Health, Vulnerabilities and Gender Relations South (SAGESUD), Paris, France
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Mbelele PM, Aboud S, Mpagama SG, Matee MI. Improved performance of Xpert MTB/RIF assay on sputum sediment samples obtained from presumptive pulmonary tuberculosis cases at Kibong'oto infectious diseases hospital in Tanzania. BMC Infect Dis 2017; 17:808. [PMID: 29284421 PMCID: PMC5747009 DOI: 10.1186/s12879-017-2931-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/19/2017] [Indexed: 02/02/2023] Open
Abstract
Background The introduction of Xpert MTB/RIF assay (Xpert) has significantly improved diagnosis of Tuberculosis (TB) in resource limited human immunodeficiency virus (HIV) endemic settings. We aimed to modify the Xpert protocol to improve the detection of Mycobacterium tuberculosis (MTB). Methods This cross sectional study was conducted among presumptive pulmonary tuberculosis (PTB) patients at Kibong’oto Infectious Diseases Hospital between August and November 2015. Each patient consented to provide 2 samples of raw sputa. One-sputum sample was sedimented using the Petroff’s method and divided into two portions. One portion of sediment was inoculated on Lowenstein-Jensen culture media and observed for any growth for up to 8 weeks. Both, raw sputum and the portions of sediments were tested separately using Xpert with a sample reagent ratio of 1:2. Mean age of patients, prevalence of MTB, Xpert sensitivity, specificity, positive and negative predictive value were calculated. An incremental sensitivity was determined. Pearson chi-square and either an independent T or Mann-Whitney U-test were used to compared categorical and continuous variables respectively. A p- value of ≤0.05 was considered significant. Results Of the 270 presumptive PTB cases, 262 were eligible for analysis. Eight (3%) were excluded due to contaminated culture. Patients’ mean age was 42.9 (±SD 15.1) years of which 173 (66%) were female. The overall prevalence of PTB was 112 (43%), of which the Xpert detected 105 (40%) in sediments and 98 (37%) in raw sputa as compared to culture which detected 85 (32%) cases of PTB. Sensitivity, specificity, positive and negative predictive values of Xpert on sputum sediments were 92%, 85%, 74% and 96% respectively. Overall, the incremental sensitivity of Xpert on sediment over raw sputum was 6%. In HIV infected Presumptive PTB, the incremental sensitivity was 12%. Conclusion Lowering the sample reagent to sediment dilution ratio increases sensitivity of Xpert on MTB detection among presumptive PTB cases, especially in HIV infected individuals.
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Affiliation(s)
- Peter M Mbelele
- Kibong'oto Infectious Diseases Hospital, P.O BOX 12, Sanya Juu, Kilimanjaro, Tanzania. .,Department of Microbiology and Immunology, School of Medicine, Muhimbili University of Health and Allied Sciences, P.O BOX 65001, Dar es Salaam, Tanzania.
| | - Said Aboud
- Department of Microbiology and Immunology, School of Medicine, Muhimbili University of Health and Allied Sciences, P.O BOX 65001, Dar es Salaam, Tanzania
| | - Stellah G Mpagama
- Kibong'oto Infectious Diseases Hospital, P.O BOX 12, Sanya Juu, Kilimanjaro, Tanzania
| | - Mecky I Matee
- Department of Microbiology and Immunology, School of Medicine, Muhimbili University of Health and Allied Sciences, P.O BOX 65001, Dar es Salaam, Tanzania
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