Test For Diagnosis Of Tuberculosis Research Articles

Innovative COVID-19 Point-of-Care Diagnostics Suitable for Tuberculosis Diagnosis: A Scoping Review.

Rapid and accurate point-of-care (POC) tuberculosis (TB) diagnostics are crucial to bridge the TB diagnostic gap. Leveraging recent advancements in COVID-19 diagnostics, we explored adapting commercially available POC SARS-CoV-2 tests for TB diagnosis in line with the World Health Organization (WHO) target product profiles (TPPs). A scoping review was conducted following PRISMA-ScR guidelines to systematically map POC antigen and molecular SARS-CoV-2 diagnostic tests potentially meeting the TPPs for TB diagnostic tests for peripheral settings. Data were gathered from PubMed/MEDLINE, bioRxiv, medRxiv, publicly accessible in vitro diagnostic test databases, and developer websites up to 23 November 2022. Data on developer attributes, operational characteristics, pricing, clinical performance, and regulatory status were charted using standardized data extraction forms and evaluated with a standardized scorecard. A narrative synthesis of the data is presented. Our search yielded 2003 reports, with 408 meeting eligibility criteria. Among these, we identified 66 commercialized devices: 22 near-POC antigen tests, 1 POC molecular test, 31 near-POC molecular tests, and 12 low-complexity molecular tests potentially adaptable for TB. The highest-scoring SARS-CoV-2 diagnostic tests were the near-POC antigen platform LumiraDx (Roche, Basel, Switzerland), the POC molecular test Lucira Check-It (Pfizer, New York, NY, USA), the near-POC molecular test Visby (Visby, San Jose, CA, USA), and the low-complexity molecular platform Idylla (Biocartis, Lausanne, Switzerland). We highlight a diverse landscape of commercially available diagnostic tests suitable for potential adaptation to peripheral TB testing. This work aims to bolster global TB initiatives by fostering stakeholder collaboration, leveraging SARS-CoV-2 diagnostic technologies for TB, and uncovering new commercial avenues to tackle longstanding challenges in TB diagnosis.

Innovative COVID-19 Point-of-Care Diagnostics Suitable for Tuberculosis Diagnosis: A Scoping Review.

Rapid and accurate point-of-care (POC) tuberculosis (TB) diagnostics are a key priority to close the TB diagnostic gap of 3.1 million people without a diagnosis. Leveraging the recent surge in COVID-19 diagnostic innovation, we explored the potential adaptation of commercially available SARS-CoV-2 tests for TB diagnosis, aligning with World Health Organization (WHO) target product profiles (TPPs). A scoping review was conducted following PRISMA-ScR guidelines to systematically map commercially available POC molecular and antigen SARS-CoV-2 diagnostic tests potentially meeting the TPPs for TB diagnostic tests for peripheral settings. Data were gathered from PubMed/MEDLINE, bioRxiv, and medRxiv, along with publicly accessible in vitro diagnostic test databases, and developer websites, up to November 23, 2022. Data on developer and test attributes, operational characteristics, pricing, and clinical performance were charted using standardized data extraction forms. Each identified test was evaluated using a standardized scorecard. A narrative synthesis of the charted data is presented. Our database search yielded 2,003 studies, from which 408 were considered eligible. Among these, we identified 58 commercialized diagnostic devices, including 17 near-POC antigen tests, one POC molecular test, 29 near-POC molecular tests, and 11 low-complexity molecular tests. We summarized the detailed characteristics, regulatory status, and clinical performance data of these tests. The LumiraDx (Roche, Switzerland) emerged as the highest- scoring near-POC antigen platform, while Visby (Visby, USA) was the highest-performing near-POC molecular platform. The Lucira Check-It (Pfizer, USA) was noted as the sole POC molecular test. The Idylla TM (Biocartis, Switzerland) was identified as the leading low- complexity molecular test. We highlight a diverse landscape of commercially available diagnostic tests suitable for potential adaptation to TB POC testing. This work aims to bolster global TB initiatives by fostering stakeholder collaboration, leveraging COVID-19 diagnostic technologies for TB diagnosis, and uncovering new commercial avenues to tackle longstanding challenges in TB diagnosis.

Perceived ease of use of Truenat among laboratory staff as a new diagnostic tool for TB in Nigeria: Result of a pilot roll-out.

In January 2020, WHO released a rapid communication on use of molecular assays as initial tests for diagnosis of tuberculosis, recommending Truenat as a replacement for smear microscopy in TB diagnosis. This study was designed to assess perceived ease of use of Truenat among Laboratory staff as a new diagnostic tool for TB in Nigeria. This study used a cross-sectional design. All trained Laboratory personnel operating the Truenat Duo equipment in 38 Truenat sites in the country were included. Information was obtained using a pre-tested self-administered questionnaire. Ease of use of Truenat was assessed using twenty-three variables on a five-point Likert scale of 1-5. The variables were analyzed quantitatively and qualitatively. Good Ease of use of Truenat was determined by proportion of respondents who answered ≥70% of the variables in the positive. All 50 Truenat Laboratory staff participated in the study. (Response rate 100%). Majority, (58%) were male. The median estimated number of tests before Laboratory staff became proficient with Truenat machine was 9 (IQR, 4-20), median number of tests to be analyzed within eight working hours was 10, (IQR = 8-15) and median time to conduct a Truelab MTBPlus test from start to finish was 60 minutes (IQR = 60-80). The commonest operational challenge that required Molbio service support was Trueprep errors/blockage, 47.4%. Overall, mean ease of use score was 4.0±0.4. Majority, (76%) had Good Ease of use of Truenat. No factor significantly influenced Ease of use of Truenat. Truenat machine is easy to use for a trained laboratory staff with minimal technical support and hence could be rolled out easily and successfully by various National TB Programs. Considering the high Trueprep challenges reported, there is need for further studies into the common errors/challenges, the contexts surrounding them and the programmatic intervention to address the high rate of Trueprep equipment faults.

Implementation of WHO guidelines on management of advanced HIV disease and its impact among TB co-infected patients in Tanzania: a retrospective follow-up study

BackgroundThe commonest causes of mortality in people living with HIV (PLHIV) are preventable and the majority can be attributed to undiagnosed tuberculosis (TB). National HIV/AIDS control programs are encouraged to implement the WHO package of interventions to improve survival among PLHIV. We assessed the implementation of the WHO TB-related package of care for Advanced HIV Disease (AHD) and its impact on treatment outcomes among HIV/TB patients in Tanzania.MethodsA retrospective cohort study was employed among HIV/AIDS patients on antiretroviral therapy from 21 public health facilities in three regions (Dar es Salaam, Coastal, and Morogoro) of Tanzania. Patients enrolled in care between January 2013- June 2017 (before the introduction of the WHO guidelines) and July 2017-Sept 2018 (during the implementation of the guidelines) were recruited. Data abstraction was done from patient hospital files using a structured questionnaire uploaded on a tablet.ResultsData from 2624 patients records were collected. Overall, 50% of patients with HIV had AHD with 7.8% of these co-infected with TB. Among AHD participants, 58.3% were female, 80.7% were from urban areas and 40.0% visited care and treatment centres as self-referrals. Implementation of the WHO AHD package of care was very low, ranging from 0% for Urine LF-LAM test done among patients with symptoms and signs of TB to 39.7% AHD concurrent with TB patients whose ART initiation was deferred for 2 weeks. Overall, the Proportion of AHD patients diagnosed with TB was 4.8%, Of which sputum Xpert as the first test for TB diagnosis was 4.4%. Five patients (0.6%) were documented to have received IPT at enrolment. Tailored counselling to ensure optimal adherence to ART for viral suppression was given to 12.1%.AHD patients co-infected with TB were retained in care more before the introduction of WHO AHD guideline (82.1%) compared to the period after the introduction of the guideline (53.9%) (p = 0.008). Clinical failure at 6 months among AHD patients was 10.6% before the guideline and 11.4% after the guideline. Immunological failure was observed in 1 patient (9.1%) before the guideline and 1 patient (7.1%) after the guideline. After the introduction of the guideline, mortality was 5.9% and no mortality was observed before the guideline. All the differences were not statistically significant.ConclusionsImplementation of the TB related WHO packages of care for AHD is very low. Except for TB diagnosis, other parameters did not improve with the introduction of the guidelines. More research is recommended to ascertain the effectiveness of guidelines as well as an understanding of the mechanisms involved.

Sensitivity of PCR analysis (melting curve method) in diagnosis of Pulmonary Tuberculosis (PTB) based on Bronchoalveolar Lavage (BAL) by bronchoscope.

Objectives:To evaluate the sensitivity of the real-time PCR assay melting curve method in the diagnosis of pulmonary tuberculosis (PTB) by analyzing bronchoalveolar lavage fluid (BALF) obtained from bronchoscopy.Methods:A total of 214 PTB patients who were treated at Xuancheng People’s Hospital respiratory and infection department during January 2018 to January 2021 were included in this study. Bronchoscopic bronchoalveolar lavage fluid (BALF) examined by polymerase chain reaction (melting curve method), BALF smear, BALF culture, lipoarabinomannan (LAM) antigen test for diagnosis of tuberculosis (TB) (LAM-TB), acid-fast stain (AFS), and serum adenosine deaminase (ADA) test were conducted respectively to compare their positive predictive values (PPVs).Results:Of the 214 patients with confirmed PTB, 84.11% were BALF melting curve method positive, significantly higher than the positive results yielded by other PTB screening tests, i.e., LAM-TB (69.16%), AFS (51.87%), ADA (49.07%), BALF culture (62.15%), and BALF smear (41.12%) (p<0.05, respectively). The PPVs were increased to 92.06%, 93.93%, 92.99%, 95.79%, and 91.12% when BALF melting curve method was performed in combination with LAM-TB, AFS, ADA, BALF culture, and BALF smear, respectively, significantly higher than that produced by BALF melting curve method or the combined use of any two of the non-BALF melting curve method tests (p<0.05, respectively).Conclusion:BALF melting curve method is an ideal diagnostic approach to PTB, which is of a higher diagnostic value compared with LAM-TB, AFS, ADA, BALF culture, and BALF smear.

Accuracy of GenoQuick MTB test in detection of Mycobacterium tuberculosis in sputum from TB presumptive patients in Uganda.

Objective:The objective of the study was to determine the diagnostic performance of the GenoQuick MTB test on heated sputum against the conventional Lowenstein–Jensen Mycobacterium tuberculosis culture as the reference method for tuberculosis diagnosis.Introduction:Fast, reliable, and easy-to-use tests for tuberculosis diagnosis are essential to achieving the Sustainable Development Goal of diagnosing and treating 90% of tuberculosis patients by 2030. We evaluated the diagnostic performance of the GenoQuick MTB, a polymerase chain reaction–lateral flow test, in Uganda, a resource-constrained, high tuberculosis- and HIV-burden setting.Methods:Fresh sputum samples from presumptive tuberculosis patients at Mulago Hospital were tested for M. tuberculosis using smear microscopy, GenoQuick MTB test, and Lowenstein–Jensen culture. For the GenoQuick MTB test, mycobacterial DNA was extracted by heating sputum at 95°C for 30 min while DNA amplification and detection were done following the manufacturer’s protocol (Hain Lifescience, Nehren, Germany). Sensitivity, specificity, and kappa agreements were calculated against Lowenstein–Jensen M. tuberculosis culture as a reference test using STATA V12.Results:Of the 86 tested samples, 30.2% had culture-confirmed pulmonary tuberculosis. Overall, sensitivity was higher for GenoQuick MTB (81%, 95% confidence interval: 60%−93%) than for smear microscopy (69%, 95% confidence interval: 48%−86%). Among people living with HIV, sensitivity was identical for GenoQuick MTB and smear tests (75%, 95% confidence interval: 42%−95%). Contrastingly, smear had a higher overall specificity (98%, 95% confidence interval: 91%−100%) than for GenoQuick MTB (92%, 95% confidence interval: 81%−97%). A similar trend of specificity was observed among the people living with HIV for smear microscopy (100%, 95% CI: 87%−100%) and for GenoQuick MTB (96%, 95% confidence interval: 81%−100%).Conclusion:The GenoQuick MTB test could be a potential tuberculosis diagnostic test given its higher sensitivity. Evaluation of this test in larger studies is recommended.

Lipoarabinomannan as a Point-of-Care Assay for Diagnosis of Tuberculosis: How Far Are We to Use It?

Tuberculosis (TB) is still a severe public health problem; the current diagnostic tests have limitations that delay treatment onset. Lipoarabinomannan (LAM) is a glycolipid that is a component of the cell wall of the bacillus Mycobacterium tuberculosis, the etiologic agent of TB. This glycolipid is excreted as a soluble form in urine. The World Health Organization has established that the design of new TB diagnostic methods is one of the priorities within the EndTB Strategy. LAM has been suggested as a biomarker to develop diagnostic tests based on its identification in urine, and it is one of the most prominent candidates to develop point-of-care diagnostic test because urine samples can be easily collected. Moreover, LAM can regulate the immune response in the host and can be found in the serum of TB patients, where it probably affects a wide variety of host cell populations, consequently influencing the quality of both innate and adaptive immune responses during TB infection. Here, we revised the evidence that supports that LAM could be used as a tool for the development of new point-of-care tests for TB diagnosis, and we discussed the mechanisms that could contribute to the low sensitivity of diagnostic testing.

The need to prioritise childhood tuberculosis case detection

The need to prioritise childhood tuberculosis case detection

Assessment of prevailing practices for identification of tuberculosis in children admitted in nutritional rehabilitation centres: A multicentre study.

Background & objectives:To eliminate tuberculosis (TB), the National TB Elimination Programme (NTEP) has given an algorithm for diagnosis and treatment of TB in children. This study was carried out to assess the prevailing practices to identify TB in severely malnourished children admitted to various nutrition rehabilitation centres (NRCs).Methods:A retrospective chart review of 41 NRCs across five States having a maximum number of NRCs was carried out. Details of children admitted to the NRCs and the investigations carried out in the form of obtaining X-ray film, tuberculin skin test (TST) and gastric aspirate for cartridge-based nucleic acid amplification test (CBNAAT) for diagnosis of TB over three months were collected.Results:A total of 2121 children with severe acute malnourished (SAM) across 41 NRCs (Bhopal, Jodhpur, Patna, Kolkata, Lucknow and Ratlam) were evaluated. X-ray of the chest was done in 473 (22%), TST was done in 135 (6%) and gastric aspirate was collected in 56 (3%) children. CBNAAT was done in only 56 SAM children. Ten children among those screened were confirmed to have pulmonary TB and were linked to treatment as per the National TB guidelines.Interpretation & conclusions:Although NTEP suggests universal screening of all malnourished children admitted in the NRCs, but the prevailing practices indicate that the NRCs are grossly under-utilizing molecular diagnostic tests for diagnosis of TB. There is a gap between prevailing practices and suggested guidelines for the identification of TB in children admitted in the NRCs.

Implementing a New Technology in Diagnostic Services for Tuberculosis in Nigeria

This article analyses the experience of the Federal Ministry of Health (FMOH), Nigeria in its partnership arrangement with some international organisations to introduce a new technology to its diagnostic services for tuberculosis (TB) by adopting the use of GeneXpert test in line with the recommendation of World Health Organisation (WHO). It was a major health service reform targeted at achieving the third sustainable development goal. Therefore, the objective of this article was to review the literature on management issues and problems of change surrounding the implementation of GeneXpert as a new technology in the diagnostic services for TB in Nigeria, and provide learning opportunities for health service administrators in resource-limited settings that might be considering such arrangement. A literature survey of articles published between 2008 and 2018 was conducted; using Google Scholar, ScienceDirect and Scopus; to identify and review articles that analyse the change management process in the introduction of GeneXpert test for TB diagnosis in Nigeria. Consequently, a total of 10 articles were critically analysed. The review showed a paucity of articles that examined how change process in the introduction of GeneXpert test for TB diagnosis was managed in Nigeria. The literature survey identified several challenges in the change process such as human resource and capacity building especially because the use of GeneXpert requires a certain level of computer literacy. In conclusion, this review highlighted the fact that the reform might be sustainable because of the adoption of decentralised service system in the implementation process.

Lateral Flow Urine Lipoarabinomannan Assay for Diagnosis of Active Tuberculosis in Adults With Human Immunodeficiency Virus Infection: A Prospective Cohort Study.

BackgroundDetection of mycobacterial lipoarabinomannan antigen in urine has emerged as a potential point-of-care test for diagnosis of tuberculosis. This study aimed to evaluate the accuracy of the lateral flow urine lipoarabinomannan (LF-LAM) assay for diagnosis of active tuberculosis among Thai adults with advanced human immunodeficiency virus (HIV) infection.MethodsHIV-infected adult patients with CD4 cell counts ≤200/μL and symptoms suggestive of active tuberculosis were prospectively recruited from both inpatient and outpatient settings at Siriraj Hospital and Chonburi Hospital in Thailand during the study period from December 2015 to March 2017. Freshly collected urine samples were applied to the Alere Determine TB LAM Ag test strip using a grade 1 cutoff, according to the manufacturer’s grading system. The diagnostic accuracy of the LF-LAM test was assessed against a microbiological reference standard (definite tuberculosis) or a composite reference standard (definite and probable tuberculosis).ResultsOf the 280 patients who were included, 72 (25.7%) had definite and 65 (23.2%) had probable tuberculosis. Among patients with definite tuberculosis, the LF-LAM test yielded a sensitivity of 75.0% and a specificity of 76.0%. It had the highest sensitivity (90.5%) in HIV-infected patients with CD4 cell counts <50/μL. It yielded a lower sensitivity (61.3%) but a higher specificity (86.0%) when compared with the composite reference standard. Among the 20 patients (14%) with false-positive results, strong band intensity was observed mostly in Mycobacterium avium complex infections. An incremental sensitivity of 11% was observed with use of acid-fast bacilli sputum smear or LF-LAM testing, compared with LF-LAM testing alone.ConclusionsThe LF-LAM test performed well in the diagnosis of active tuberculosis in selected patients with more advanced tuberculosis and coexisting HIV disease.

Efficacy of Xpert MTB/RIF Assay in the Diagnosis of Smear Negative HIV Seropositive Pulmonary Tuberculosis Patients

Background: Tuberculosis (TB) is the most common presenting illness and leading cause of death among people living with HIV(PLHIV). Diagnosis of TB among PLHIV is challenging as false negative results are common with direct microscopy (DM) and culture takes long time. WHO (2013) recommended Xpert MTB/RIF assay as an initial test for diagnosis of TB in PLHIV. Methods: The present study was conducted on 142 HIV seropositive patients who were clinically suspected to have TB. The sputum specimens obtained from these patients were divided into two parts; one was processed by DM and the other was used for Xpert MTB/RIF assay. Result: Of the 142 HIV seropositive patients, 90(63.3%) were in the age group of 15-40 years and majority 91(64.08%) were males. Out of 142 sputum specimens collected from these patients, only 5(3.52%) were positive by DM and 31(21.83%) by Xpert MTB/RIF assay. Statistically the difference between the two was significant (p value <0.005). Xpert MTB/RIF assay showed rifampicin resistant in 2(6.45%) specimen. Of the 137 smear negative specimens, Xpert MTB/RIF assay gave positive result in 27 (19.70%). Thus, the sensitivity, specificity, PPV, NPV of the Xpert MTB/RIF assay in comparison to DM was 80% (95%CI=37.6- 96.4), 80.29% (95%CI=72.8-86.1), 12.90% (95%CI=4.21-30.76), 99.09%(95%CI=94.3-99.9) respectively. Conclusion: Xpert MTB/RIF assay was found to be a sensitive, specific and rapid method for diagnosis of TB and rifampicin resistance in smear negative PLHIV. It’s availability as an initial diagnostic test in PLHIV could significantly reduce the delay in initiation of treatment and prevent the transmission of the disease.

Effect of Xpert MTB/RIF on clinical outcomes in routine care settings: individual patient data meta-analysis.

SummaryBackgroundXpert MTB/RIF, the most widely used automated nucleic acid amplification test for tuberculosis, is available in more than 130 countries. Although diagnostic accuracy is well documented, anticipated improvements in patient outcomes have not been clearly identified. We performed an individual patient data meta-analysis to examine improvements in patient outcomes associated with Xpert MTB/RIF.MethodsWe searched PubMed, Embase, ClinicalTrials.gov, and the Pan African Clinical Trials Registry from inception to Feb 1, 2018, for randomised controlled trials (RCTs) comparing the use of Xpert MTB/RIF with sputum smear microscopy as tests for tuberculosis diagnosis in adults (aged 18 years or older). We excluded studies of patients with extrapulmonary tuberculosis, and studies in which mortality was not assessed. We used a two-stage approach for our primary analysis and a one-stage approach for the sensitivity analysis. To assess the primary outcome of cumulative 6-month all-cause mortality, we first performed logistic regression models (random effects for cluster randomised trials, with robust SEs for multicentre studies) for each trial, and then pooled the odds ratio (OR) estimates by a fixed-effects (inverse variance) or random-effects (Der Simonian Laird) meta-analysis. We adjusted for age and gender, and stratified by HIV status and previous tuberculosis-treatment history. The study protocol has been registered with PROSPERO, number CRD42014013394.FindingsOur search identified 387 studies, of which five RCTs were eligible for analysis. 8567 adult clinic attendees (4490 [63·5%] of 7074 participants for whom data were available were HIV-positive) were tested for tuberculosis with Xpert MTB/RIF (Xpert group) versus sputum smear microscopy (sputum smear group), across five low-income and middle-income countries (South Africa, Brazil, Zimbabwe, Zambia, and Tanzania). The primary outcome (reported in three studies) occurred in 182 (4·5%) of 4050 patients in the Xpert group and 217 (5·3%) of 4093 patients in the smear group (pooled adjusted OR 0·88, 95% CI 0·68–1·14 [p=0·34]; for HIV-positive individuals OR 0·83, 0·65–1·05 [p=0·12]). Kaplan-Meier estimates showed a lower rate of death (12·73 per 100 person-years in the Xpert group vs 16·38 per 100 person-years in the sputum smear group) for HIV-positive patients (hazard ratio 0·76, 95% CI 0·60–0·97; p=0·03). The risk of bias was assessed as reasonable and the statistical heterogeneity across studies was low (I2<20% for the primary outcome).InterpretationDespite individual patient data analysis from five RCTs, we were unable to confidently rule in nor rule out an Xpert MTB/RIF-associated reduction in mortality among outpatients tested for tuberculosis. Reduction in mortality among HIV-positive patients in a secondary analysis suggests the possibility of population-level impact.

757. Community Prevalence of Bacteriologically Confirmed Pulmonary Tuberculosis: A 7-Year Retrospective Study

BackgroundIt is estimated that about 40% of the Indian population is infected with Mycobacterium tuberculosis (TB), the vast majority of whom have latent TB. However, asymptomatic pulmonary carriage of the TB bacteria contributes to sustenance of the disease in the community and subsequent transmission. The present study was carried out to see the prevalence of culture positive pulmonary tuberculosis in apparently asymptomatic individuals from the community.MethodsThe study population consisted of individuals wishing to migrate to the USA/UK/Canada/Australia and submitting for the mandatory health check prior to obtaining the Visa. Chest X-ray was the initial screening test for diagnosis of tuberculosis. Individuals with any X-ray abnormalities were directed to submit three sputum samples for microscopy and culture which was done on automated culture systems (BacTALERT and MGIT). First-line drug susceptibility (INH, Rifampicin, Pyrazinamide, Ethambutol, Streptomycin) testing data were retrieved wherever available. Data were obtained for a period of 7 years from August 2010 to July 2017.ResultsA total of 140,499 individuals presented for the health check. Of these, 1,002 (0.7%) were further investigated using sputum microscopy and culture based on chest X-ray findings. Of these, 42 (0.4%) individuals were sputum culture positive for Mycobacterium tuberculosis. Except two, none had any respiratory complaints. Eleven (27.5%) of them were smear positive for acid fast bacilli. Most of the patients (30%) belonged to the age group of 18–25 years. Eighty-four percent had no prior history of tuberculosis or treatment for TB. Fifty-nine percent isolates were sensitive to all first-line drugs (Isoniazid, rifampicin, pyrazinamide, ethambutol and streptomycin). Twenty-seven percent were resistant to pyrazinamide alone. Fourteen percent were resistant to more than one first-line drug. There were no cases of multidrug resistance.ConclusionThis is a unique large-scale study which assesses prevalence of culture positive pulmonary tuberculosis in the urban Indian community. It stresses the need for more stringent public health measures to curb transmission of the disease in such a high endemic region such as India.Disclosures All authors: No reported disclosures.

Comparison between tests for tuberculosis diagnosis in slaughtered bovines

ABSTRACT: Our goal for this article is to compare several different diagnosis tests for bovine tuberculosis identification. We have performed bacterial isolation, histopathological characterization, acid-fast bacilli (AFB) identification and M. bovis DNA detection. Lesions suggestive of Tuberculosis were sampled from bovine lymph nodes during slaughtering of bovines at an abattoir that operates under federal inspection. The bacterial isolation was performed in solid culture mediums, the histopathological characterization was made by Hematoxylin-eosinstaining, and AFB identification by Ziehl-Neelsen staining. Bacterial DNA detection was performed by Polymerase Chain Reaction (PCR) using DNA from two different sources, directly collected from the tuberculosis-like lesions (PCR followed by nested PCR) and from isolated bacteria. We have concluded that the multi-step approach, including histopathological characterization, bacterial isolation and AFB identification, is strongly recommended to diagnose tuberculosis in bovines. Furthermore, PCR assays using specimens of lesions suggestive of tuberculosis are a faster and more promising way to diagnose the disease. However, it should not be used alone due to the low sensitivity shown in this study.

Higher serum 25-hydroxyvitamin D concentrations are associated with active pulmonary tuberculosis in hospitalised HIV infected patients in a low income tropical setting: a cross sectional study

BackgroundThe inherent risk of developing tuberculosis (TB) in HIV- infected individuals is further enhanced by hypovitaminosis D. Interventions that offset HIV-associated immune deterioration potentially arrest disease progression and incidence of opportunistic infections including TB. Despite conflicting reports on association between vitamin D deficiency (VDD) and risk of TB, vitamin D (VD) supplementation remains a promising intervention.MethodsWe conducted a comparative cross-sectional study on 145 HIV+/pulmonary TB+ (PTB) and 139 HIV+/PTB− hospitalised patients to investigate association of vitamin D status and risk of PTB. Stratified random sampling was used to select archived serum specimens from participants enrolled in a randomised controlled trial (RCT) conducted to investigate the impact of using a point-of-care urine lipoarabinomannan strip test for TB diagnosis. PTB status was confirmed using sputum smear microscopy, culture or GeneXpert MTB/RIF. Serum 25-hydroxyvitamin D [25(OH) D] concentrations were assayed by competitive chemiluminescent immunoassay prior to commencement of anti-TB treatment. Effect of VD status on duration of hospital stay and patient outcomes on follow up at 8 weeks were also investigated. Median serum 25(OH) D concentrations were compared using Mann-Whitney test and covariates of serum VD status were assessed using logistic regression analysis.ResultsOverall VDD prevalence in the cohort was 40.9% (95% CI: 35.1–46.8). Median serum 25(OH)D concentrations were significantly higher in HIV+/PTB+ group (25.3 ng/ml, IQR:18.0–33.7) compared to the HIV+/PTB− group (20.4 ng/ml, IQR:14.6–26.9), p = 0.0003. Patients with serum 25(OH) D concentration ≥ 30 ng/ml were 1.9 times more likely to be PTB+ compared to those with serum 25(OH) D concentrations < 30 ng/ml (odds ratio (OR) 1.91; 95% CI 1.1–3.2). PTB-related death was associated with higher odds of having 25(OH) D levels≥30 ng/ml. Age, gender, CD4+ count, combination antiretroviral therapy (cART) status, efavirenz based cART regimen and length of hospital stay were not associated with vitamin D status.ConclusionsThe finding of an association between higher serum 25(OH) D concentrations and active PTB and TB-related mortality among hospitalised HIV-infected patients in the present study is at variance with the commonly reported association of hypovitaminosis and susceptibility to TB. Our findings though, are in concordance with a small pool of reports from other settings.

Comparison of Interferon-γ Release Assays and the Tuberculin Skin Test for Diagnosis of Tuberculosis in Human Immunodeficiency Virus: A Systematic Review.

BackgroundIt remains uncertain if interferon-γ release assays (IGRAs) are superior to the tuberculin skin test (TST) for the diagnosis of active tuberculosis (TB) or latent tuberculosis infection (LTBI) in immunosuppressed populations including people with human immunodeficiency virus (HIV) infection. The purpose of this study was to systematically review the performance of IGRAs and the TST in people with HIV with active TB or LTBI in low and high prevalence TB countries.MethodsWe searched the MEDLINE database from 1966 through to January 2017 for studies that compared results of the TST with either the commercial QuantiFERON-TB Gold in Tube (QFTGT) assay or previous assay versions, the T-SPOT.TB assay or in-house IGRAs. Data were summarized by TB prevalence. Tests for concordance and differences in proportions were undertaken as appropriate. The variation in study methodology was appraised.ResultsThirty-two studies including 4,856 HIV subjects met the search criteria. Fourteen studies compared the tests in subjects with LTBI in low TB prevalence settings. The QFTGT had a similar rate of reactivity to the TST, although the first-generation version of that assay was reactive more commonly. IGRAs were more frequently positive than the TST in HIV infected subjects with active TB. There was considerable study methodology and population heterogeneity, and generally low concordance between tests. Both the TST and IGRAs were affected by CD4 T-cell immunodeficiency.ConclusionOur review of comparative data does not provide robust evidence to support the assertion that the IGRAs are superior to the TST when used in HIV infected subjects to diagnose either active TB or LTBI.

Serial survey shows community intervention may contribute to increase in knowledge of Tuberculosis in 30 districts of India.

BackgroundCorrect knowledge about Tuberculosis (TB) is essential for appropriate healthcare seeking behaviour and to accessing diagnosis and treatment services timely. There are several factors influencing knowledge about TB. The present study was conducted to assess the change in community knowledge of Tuberculosis (TB) and its association with respondent’s socio-demographic characteristics in two serial knowledge-attitude-practice surveys.MethodsCommunity level interventions including community meetings with youth groups, village health committees and self-help groups and through mass media activities were undertaken to create awareness and knowledge about TB and service availability. Increase in knowledge on TB and its association with respondent’s socio-demographic characteristics was assessed by two serial KAP surveys in 2010–2011 (baseline) and 2012–2013 (midline) in 30 districts of India. Correct knowledge of TB was assessed by using lead questions and scores were assigned. The composite score was dichotomized into two groups (score 0–6, poor TB knowledge and score 7–13, good TB knowledge).ResultsIn baseline and midline survey, 4562 and 4808 individuals were interviewed. The correct knowledge about TB; cough ≥2 weeks, transmission through air, 6–8 months treatment duration, and free treatment increased by 7 % (p-value <0.05), 11 % (p-value <0.05), 2 % (p-value <0.05), and 8 % (p-value <0.05) in midline compared to baseline, respectively. The knowledge on sputum smear test for diagnosis of TB was 66 % in both surveys while knowledge on availability of free treatment and that TB is curable disease decreased by 5 % and 2 % in midline (p-0.001), compared to baseline, respectively. The mean score for correct knowledge about TB increased from 60 % in baseline to 71 % in midline which is a 11 % increase (p-value <0.001). The misconception regarding on transmission of TB by- sharing of food and clothes and handshake persisted in midline. Respondents residing in northern (OR, 2.2, 95 % CI, 1.7–2.6) and western districts (OR, 3.4, 95 % CI, 2.7–4.1) of India and age groups- 25–34 years (OR, 1.3; 95 % CI, 1.1–1.6) and 45–44 years (OR, 1.4; 95 % CI, 1.1–1.7)- were independently associated with good TB knowledge.ConclusionsThe knowledge about TB has increased over a period of 2 years and this may be attributable to the community intervention in 30 districts of India. The study offers valuable lesson for designing TB related awareness programmes in India and in other high burden countries.

Role of Molecular Tests for Diagnosis of Tuberculosis in Children

Role of Molecular Tests for Diagnosis of Tuberculosis in Children

Diagnosis of tuberculosis by using a nucleic acid amplification test in an urban population with high HIV prevalence in the United States.

BackgroundUse of nucleic acid amplification tests (NAAT) for the diagnosis of Mycobacterium tuberculosis (TB) has been recommended on respiratory specimens submitted for acid-fast bacilli (AFB) testing. It also helps distinguish between TB and non-tuberculous mycobacteria (NTM) species in a setting where NTM rates are relatively high. The purposes of this study are to describe the trend and characteristics of all AFB smear-positive respiratory samples that underwent amplified Mycobacterium tuberculosis direct (MTD) testing, a type of NAAT, and to evaluate the clinical utility and necessity of the test for diagnosis of TB in a population with high-HIV prevalence.MethodsProspective diagnostic testing and retrospective data analyses were conducted on all AFB smear-positive respiratory samples that underwent MTD testing from 2001 to 2011 at Grady Memorial Hospital (GMH), Atlanta, USA. The test performance was compared to culture.ResultsA total of 2,240 AFB smear-positive specimens from 1,412 patients were tested and analyzed in the study. The proportion of specimens that were culture-positive for TB was 28.5%. Sensitivity, specificity, positive predictive value, and negative predictive value of the MTD were 99.0%, 98.0%, 95.3% and 99.6%, respectively. A downward trend was observed in the yearly numbers as well as the proportions of MTD-positive specimens during the study period (p<0.01). There were 2,027 (90.5%) specimens from patients with known HIV status, of which 70.6% was HIV positive and the majority of them (81.8%) had CD4 counts of less than 200 cells/µL. HIV-positives were more likely to have NTM compared to HIV negatives (67.7% vs. 35.4%, p<0.01).ConclusionDespite the decrease in the incidence of TB, NAAT continues to be an accurate and important diagnostic test in a population with high HIV prevalence, and it differentiates TB and NTM organisms.