High Tuberculosis Burden Settings Research Articles

The utility of artificial intelligence in identifying radiological evidence of lung cancer and pulmonary tuberculosis in a high-burden tuberculosis setting

Background. Artificial intelligence (AI), using deep learning (DL) systems, can be utilised to detect radiological changes of various pulmonary diseases. Settings with a high burden of tuberculosis (TB) and people living with HIV can potentially benefit from the use of AI to augment resource-constrained healthcare systems. Objective. To assess the utility of qXR software (AI) in detecting radiological changes compatible with lung cancer or pulmonary TB (PTB). Methods. We performed an observational study in a tertiary institution that serves a population with a high burden of lung cancer and PTB. In total, 382 chest radiographs that had a confirmed diagnosis were assessed: 127 with lung cancer, 144 with PTB and 111 normal. These chest radiographs were de-identified and randomly uploaded by a blinded investigator into qXR software. The output was generated as probability scores from predefined threshold values. Results. The overall sensitivity of the qXR in detecting lung cancer was 84% (95% confidence interval (CI) 80 - 87%), specificity 91% (95% CI 84 - 96%) and positive predictive value of 97% (95% CI 95 - 99%). For PTB, it had a sensitivity of 90% (95% CI 87 - 93%) and specificity of 79% (95% CI 73 - 84%) and negative predictive value of 85% (95% CI 79 - 91%). Conclusion. The qXR software was sensitive and specific in categorising chest radiographs as consistent with lung cancer or TB, and can potentially aid in the earlier detection and management of these diseases.

An early and trustable indicator suggestive of non-tuberculosis mycobacteria isolation in a high tuberculosis burden setting

Distinguishing between nontuberculous mycobacterial (NTM) lung infections and pulmonary tuberculosis becomes challenging due to their similar clinical manifestations and radiological images. Consequently, instances of delayed diagnosis or misdiagnosis are highly frequent. A feasible and reliable indicator of the existence of NTM in the early stages of the disease would help to solve this dilemma. In this study, we evaluated the potential of smear-positive and Xpert assay (Cepheid, USA) negative outcomes as an early indicator of possible NTM infection in a high TB-burden setting retrospectively and prospectively. During the study period, 12·77% (138/1081) of the smear-positive cases yielded negative outcomes with the simultaneous Xpert assay. From the 110 patients who yielded smear-positive/Xpert-negative outcomes and cultivated strain as well, 105 (95·45%) were proved to have NTM isolated. By incorporating an additional criterion of a negative result from the Interferon-gamma release assay, the accuracy of the screening method reached 100%. Regarding the NTM presence prediction value, smear-positive/Xpert-negative has a sensitivity of 24·86% (45/181) in all NTM isolated cases but 93·75-96·55% accuracy in retrospective study or 93·75% accuracy in prospective study in smear-positive NTM isolated cases. In addition, the specificity was ∼99·47% (943/948) in smear-positive tuberculosis cases. The clue of the presence of NTM could be obtained on the first day of the hospital visit due to the point of care (POC) feature of smear testing and Xpert assay. About one-fourth of the NTM-isolated patients would benefit from this rapid, convenient, and reliable screening strategy in the given circumstance. Smear-positive/Xpert-negative outcome is an early, trustable indicator that is indicative of NTM isolation.

Performance of a stool-based quantitative PCR assay for the diagnosis of tuberculosis in adolescents and adults: a multinational, prospective diagnostic accuracy study

Despite increasing availability of rapid molecular tests for the diagnosis of tuberculosis in high-burden settings, many people with tuberculosis are undiagnosed. Reliance on sputum as the primary specimen for tuberculosis diagnostics contributes to this diagnostic gap. We evaluated the diagnostic accuracy and additive yield of a novel stool quantitative PCR (qPCR) assay for the diagnosis of tuberculosis in three countries in Africa with high tuberculosis burdens. We undertook a prospective diagnostic accuracy study in Eswatini, Mozambique, and Tanzania from Sept21, 2020, to Feb 2, 2023, to compare the diagnostic accuracy for tuberculosis of a novel stool qPCR test with the current diagnostic standard for Mycobacterium tuberculosis DNA detection from sputum and stool, Xpert-MTB/RIF Ultra (Xpert Ultra). Sputum, stool, and urine samples were provided by a cohort of participants, aged 10 years or older, diagnosed with tuberculosis. Participants with tuberculosis (cases) were enrolled within 72 h of treatment initiation for tuberculosis diagnosed clinically or following laboratory confirmation. Participants without tuberculosis (controls) consisted of household contacts of the cases who did not develop tuberculosis during a 6-month follow-up. The performance was compared with a robust composite microbiological reference standard (CMRS). The cohort of adolescents and adults (n=408) included 268 participants with confirmed or clinical tuberculosis (cases), 147 (55%) of whom were living with HIV, and 140 participants (controls) without tuberculosis. The sensitivity of the novel stool qPCR was 93·7% (95% CI 87·4-97·4) compared with participants with detectable growth on M tuberculosis culture, and 88·1% (81·3-93·0) compared with sputum Xpert Ultra. The stool qPCR had an equivalent sensitivity as sputum Xpert Ultra (94·8%, 89·1-98·1) compared with culture. Compared with the CMRS, the sensitivity of the stool qPCR was higher than the current standard for tuberculosis diagnostics on stool, Xpert Ultra (80·4%, 73·4-86·2 vs 73·5%, 66·0-80·1; p=0·025 on paired comparison). The qPCR also identified 17-21% additional tuberculosis cases compared to sputum Xpert Ultra or sputum culture. In controls without tuberculosis, the specificity of the stool qPCR was 96·9% (92·2-99·1). In this study, a novel qPCR for the diagnosis of tuberculosis from stool specimens had a higher accuracy in adolescents and adults than the current diagnostic PCR gold standard on stool, Xpert-MTB/RIF Ultra, and equivalent sensitivity to Xpert-MTB/RIF Ultra on sputum. National Institutes of Health (NIH) Allergy and Infectious Diseases, and NIH Fogarty International Center.

Applicability of artificial intelligence-based computer-aided detection (AI–CAD) for pulmonary tuberculosis to community-based active case finding

BackgroundArtificial intelligence-based computer-aided detection (AI–CAD) for tuberculosis (TB) has become commercially available and several studies have been conducted to evaluate the performance of AI–CAD for pulmonary tuberculosis (TB) in clinical settings. However, little is known about its applicability to community-based active case-finding (ACF) for TB.MethodsWe analysed an anonymized data set obtained from a community-based ACF in Cambodia, targeting persons aged 55 years or over, persons with any TB symptoms, such as chronic cough, and persons at risk of TB, including household contacts. All of the participants in the ACF were screened by chest radiography (CXR) by Cambodian doctors, followed by Xpert test when they were eligible for sputum examination. Interpretation by an experienced chest physician and abnormality scoring by a newly developed AI–CAD were retrospectively conducted for the CXR images. With a reference of Xpert-positive TB or human interpretations, receiver operating characteristic (ROC) curves were drawn to evaluate the AI–CAD performance by area under the ROC curve (AUROC). In addition, its applicability to community-based ACFs in Cambodia was examined.ResultsTB scores of the AI–CAD were significantly associated with the CXR classifications as indicated by the severity of TB disease, and its AUROC as the bacteriological reference was 0.86 (95% confidence interval 0.83–0.89). Using a threshold for triage purposes, the human reading and bacteriological examination needed fell to 21% and 15%, respectively, detecting 95% of Xpert-positive TB in ACF. For screening purposes, we could detect 98% of Xpert-positive TB cases.ConclusionsAI–CAD is applicable to community-based ACF in high TB burden settings, where experienced human readers for CXR images are scarce. The use of AI–CAD in developing countries has the potential to expand CXR screening in community-based ACFs, with a substantial decrease in the workload on human readers and laboratory labour. Further studies are needed to generalize the results to other countries by increasing the sample size and comparing the AI–CAD performance with that of more human readers.

Assessment of Conventional and Molecular Methods in the Routine Management of Tuberculosis in a High Tuberculosis Burden Setting

Background and aims: India is a high-burden tuberculosis region and a drug-resistance hotspot. Despite numerous reports of pulmonary tuberculosis (PTB) cases, there needs to be more literature available on the importance of diagnostic methods in the case of extrapulmonary tuberculosis (EPTB). A prospective study was carried out from July 2017 to June 2018 to compare the efficacy of conventional and molecular methods in detecting PTB and EPTB cases. Methods: 1000 presumptive PTB and 412 EPTB cases were subjected to staining (Ziehl-Neelson and fluorescent staining), culture, GeneXpert, and line probe assay. Results: The sensitivity, specificity, and strength of association, i.e., kappa (k) value of LED-FM, ZN, and GeneXpert, were calculated using standard formulae using solid culture as the gold standard. The sensitivity of GeneXpert in smear-positive/culture-positive PTB was comparable with the smear-negative/culture-positive PTB cases (95.7% Vs. 87.5%) with an overall sensitivity and specificity of 90.5% and 90.1% in EPTB cases, respectively. However, sensitivity was lower for pleural fluid (75%) and tissues (85.7%). In pulmonary instances, 10% (6.7% RIF + INH resistant and 3.3%INH monoresistant) drug resistance was observed, and no drug resistance was found in extra-pulmonary samples. Conclusion: Among conventional methods, Fluorescent staining is more sensitive than Ziehl-Neelson (ZN) staining, while the sensitivity of GeneXpert varies w.r.t type of sample using culture positivity as the gold standard. The present study suggests the promotion of universal DST for all individuals with TB to control drug-resistant tuberculosis.

Healthcare worker perceived barriers and facilitators to implementing a tuberculosis preventive therapy program in rural South Africa: a content analysis using the consolidated framework for implementation research

BackgroundSouth African national tuberculosis (TB) guidelines, in accordance with the World Health Organization, recommend conducting routine household TB contact investigation with provision of TB preventive therapy (TPT) for those who qualify. However, implementation of TPT has been suboptimal in rural South Africa. We sought to identify barriers and facilitators to TB contact investigations and TPT management in rural Eastern Cape, South Africa, to inform the development of an implementation strategy to launch a comprehensive TB program.MethodsWe collected qualitative data through individual semi-structured interviews with 19 healthcare workers at a district hospital and four surrounding primary-care clinics referring to the hospital. The consolidated framework for implementation research (CFIR) was used to develop interview questions as well as guide deductive content analysis to determine potential drivers of implementation success or failure.ResultsA total of 19 healthcare workers were interviewed. Identified common barriers included lack of provider knowledge regarding efficacy of TPT, lack of TPT documentation workflows for clinicians, and widespread community resource constraints. Facilitators identified included healthcare workers high interest to learn more about the effectiveness of TPT, interest in problem-solving logistical barriers in provision of comprehensive TB care (including TPT), and desire for clinic and nurse-led TB prevention efforts.ConclusionThe use of the CFIR, a validated implementation determinants framework, provided a systematic approach to identify barriers and facilitators to TB household contact investigation, specifically the provision and management of TPT in this rural, high TB burden setting. Specific resources—time, trainings, and evidence—are necessary to ensure healthcare providers feel knowledgeable and competent about TPT prior to prescribing it more broadly. Tangible resources such as improved data systems coupled with political coordination and funding for TPT programming are essential for sustainability.

A user-centred implementation strategy for tuberculosis contact investigation in Uganda: protocol for a stepped-wedge, cluster-randomised trial

BackgroundTuberculosis(TB) is among the leading causes of infectious death worldwide. Contact investigation is an evidence-based, World Health Organisation-endorsed intervention for timely TB diagnosis, treatment, and prevention but has not been widely and effectively implemented.MethodsWe are conducting a stepped-wedge, cluster-randomised, hybrid Type III implementation-effectiveness trial comparing a user-centred to a standard strategy for implementing TB contact investigation in 12 healthcare facilities in Uganda. The user-centred strategy consists of several client-focused components including (1) a TB-education booklet, (2) a contact-identification algorithm, (3) an instructional sputum-collection video, and (4) a community-health-rider service to transport clients, CHWs, and sputum samples, along with several healthcare-worker-focused components, including (1) collaborative improvement meetings, (2) regular audit-and-feedback reports, and (3) a digital group-chat application designed to develop a community of practice. Sites will cross-over from the standard to the user-centred strategy in six, eight-week transition steps following a randomly determined site-pairing scheme and timeline. The primary implementation outcome is the proportion of symptomatic close contacts completing TB evaluation within 60 days of TB treatment initiation by the index person with TB. The primary clinical effectiveness outcomes are the proportion of contacts diagnosed with and initiating active TB disease treatment and the proportion initiating TB preventative therapy within 60 days. We will assess outcomes from routine source documents using intention-to-treat analyses. We will also conduct nested mixed-methods studies of implementation fidelity and context and perform cost-effectiveness and impact modelling. The Makerere School of Public Health IRB(#554), the Uganda National Council for Science and Technology(#HS1720ES), and the Yale Institutional Review Board(#2000023199) approved the study and waived informed consent for the main trial implementation-effectiveness outcomes. We will submit results for publication in peer-reviewed journals and disseminate findings to local policymakers and representatives of affected communities.DiscussionThis pragmatic, quasi-experimental implementation trial will inform efforts to find and prevent undiagnosed persons with TB in high-burden settings using contact investigation. It will also help assess the suitability of human-centred design and communities of practice for tailoring implementation strategies and sustaining evidence-based interventions in low-and-middle-income countries.Trial registrationThe trial was registered(ClinicalTrials.gov Identifier NCT05640648) on 16 November 2022, after the trial launch on 7 March 2022.

Significance of non-granulomatous cytomorphology on fine needle aspirate in lymphadenitis cases classified as tuberculous by using a composite reference standard.

Fine needle aspiration cytology (FNAC) is established as a first line investigation for tuberculous lymphadenitis (TBLA). We aimed to describe the various cytomorphologic features of tuberculosis (TB) on FNAC and their contribution in the diagnostic decision-making in suspected TBLA cases. Patients with presumptive TBLA were prospectively enrolled (n = 266) and subjected to routine diagnostic work-up for TB, including FNAC samples, and followed until the end of treatment. Patients were categorized as TB or non-TB cases based on a composite reference standard of which the various cytomorphologic patterns were compared. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy was calculated using cross-tabulation. Fifty-six patients were categorized as bacteriologically confirmed TB, 102 as clinically confirmed TB and 108 as non-TB. The most common cytomorphologic pattern among TB cases (59%) was granulomatous inflammation with necrosis, however, about one-third of tuberculous lymphadenitis patients presented with non-granulomatous inflammation, with 21% showing only necrosis and 13% presenting with a reactive pattern. The overall sensitivity and specificity of FNAC was 85% and 66%, respectively. We found that about one-third of TBLA patients presented without granulomas on FNA, highlighting the importance of considering TB in a wide spectrum of cytomorphology in a high TB burden setting. Our study supports the use of FNAC as a first-line investigation tool for diagnosing TBLA in a low-resource setting due to its relative simplicity and good sensitivity. However, the low specificity of FNAC, emphasizes the need for a second-tier confirmatory test with improved specificity.

Tuberculosis and malnutrition: The European perspective

Tuberculosis (TB) is a leading infectious cause of death worldwide, despite ongoing efforts to limit its incidence and mortality. Although the European Region has made gains in TB incidence and mortality, it now contends with increasing numbers of multidrug- and rifampicin-resistant tuberculosis (MDR/RR-TB). Malnutrition is a major contributor to the burden of TB and may also be directly caused or enhanced by the onset of TB. The presence of malnutrition may worsen TB and MDR/RR-TB related treatment outcomes and contribute to growing TB drug-resistance. Preventing and treating all forms of malnutrition is an important tool to limit the spread of TB worldwide and improve TB outcomes and treatment efficacy. We carried out a scoping review of the existing evidence that addresses malnutrition in the context of TB. Our review found malnutrition increased the risk of developing TB in high-burden settings and increased the likelihood of developing unfavorable treatment outcomes, including treatment failure, loss to follow-up, and death. The potential impact of nutritional care and improved nutritional status on patient prognosis was more difficult to evaluate due to heterogeneity of patient populations, treatment protocols, and treatment durations and goals. High-quality trials that consider malnutrition as a major risk factor and relevant treatment target when designing effective strategies to limit TB spread and mortality are needed to inform evidence-based practice. In TB patients, we suggest that widespread and regular nutritional screening, assessment, and counselling, has the potential to increase effectiveness of TB management strategies and improve patient quality of life, overall outcomes, and survival.

Beyond patient delay, navigating structural health system barriers to timely care and treatment in a high burden TB setting in Papua New Guinea

ABSTRACT Tuberculosis (TB) is a major public health issue in Papua New Guinea, with incidence rates particularly high in the South Fly District of Western Province. We present three case studies, along with additional vignettes, that were derived from interviews and focus groups carried out between July 2019 and July 2020 of people living in rural areas of the remote South Fly District depicting their challenges accessing timely TB diagnosis and care; most services within the district are only offered offshore on Daru Island. The findings detail that rather than ‘patient delay’ attributed to poor health seeking behaviours and inadequate knowledge of TB symptoms, many people were actively trying to navigate structural barriers hindering access to and utilisation of limited local TB services. The findings highlight a fragile and fragmented health system, a lack of attention given to primary health services, and undue financial burdens placed on people living in rural and remote areas associated with costly transportation to access functioning health services. We conclude that a person-centred and effective decentralised model of TB care as outlined in health policies is imperative for equitable access to essential health care services in Papua New Guinea.

Endosonographic characteristics of mediastinal lymph nodes for predicting malignancy in high tuberculosis burden settings: a study of 774 subjects

ABSTRACT Background Whether sonographic features of mediastinal lymph nodes can differentiate malignancy from tuberculosis remains unclear. Research design and methods We retrospectively identified subjects with a confirmed diagnosis of tuberculosis or malignancy on endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Our primary objective was to compare the endosonographic characteristics of lymph nodes on EBUS between tuberculosis and malignancy. Our secondary objective was to assess the diagnostic performance of endosonographic characteristics in predicting malignancy. Results We included 774 subjects (1,498 lymph nodes) with a confirmed diagnosis of tuberculosis (n = 497) or malignancy (n = 277). Distinct lymph node margins (84.1% vs. 93.8%, P < 0.001) and coagulation necrosis sign (11.2% vs. 29.8%, P < 0.001) were less common in malignancy than tuberculosis. The absence of central hilar structure had the highest sensitivity (92.1%) for malignancy. Endosonographic characteristics had poor specificity for malignancy(round shape and coagulation necrosis sign, 77.3% and 70.2%. In multivariate analysis, coagulation necrosis sign was associated with a lower odds of malignancy (odds ratio 0.45 [95% confidence intervals, 0.21–0.95]). Conclusions Endosonographic characteristics, such as round shape and the coagulation necrosis sign, are not specific for malignancy in high tuberculosis prevalence areas.

The Practical Value of Xpert MTB/RIF Ultra for Diagnosis of Pulmonary Tuberculosis in a High Tuberculosis Burden Setting: a Prospective Multicenter Diagnostic Accuracy Study.

ABSTRACTDue to the probability of decreased specificity, the practical value of performing the Xpert MTB/RIF Ultra (Xpert Ultra) assay over the Xpert assay for diagnosing pulmonary tuberculosis (TB) and rifampicin (RIF) resistance in a high TB burden setting was evaluated. Participants were recruited consecutively in three tertiary hospitals in China and allocated to the TB case detection and/or rifampicin (RIF) resistance detection group. Each sputum specimen was subjected to smear, MGIT960 liquid culture, and Xpert, and Xpert Ultra assay in parallel. Drug susceptibility testing was conducted for all recovered isolates in the RIF resistance detection group. In total, 1,079 patients were recruited to the case detection group and 450 to the RIF resistance detection group. Xpert Ultra had higher sensitivity than Xpert (92.26%, 322/349 versus 89.40%, 312/349; P = 0.006), whereas the most prominent increase was identified in the smear-negative patients (83.70% versus 78.52%; P = 0.039). The specificity of Xpert Ultra was slightly lower than that of Xpert (96.30%, 495/514 versus 98.25%, 505/514; P = 0.055). Reclassifying trace results as negative resulted in a 4.01% loss of sensitivity (from 92.26% to 88.25%) accompanied by a 1.37% gain in specificity (from 96.30% to 97.67%). Both the sensitivity (97.64% versus 99.21%, P = 0.313) and specificity (96.90% versus 97.21%, P = 0.816) of Xpert Ultra and Xpert for detection RIF resistance were comparable. In conclusion, Xpert Ultra could improve the diagnosis of smear-negative pulmonary TB in contrast to the Xpert assay. A high percentage of TB history did not significantly decrease the specificity of the test, which supports the potential role of Xpert Ultra as an initial diagnostic tool for TB.IMPORTANCE Xpert Ultra is more sensitive than Xpert, especially in smear-negative TB. A high percentage of TB history in the non-TB population did not significantly affect the reliability of the assay, which supports the potential role of Xpert Ultra as an initial diagnostic tool for TB.

Integrating interferon-gamma release assay testing into provision of tuberculosis preventive therapy is feasible in a tuberculosis high burden resource-limited setting: A mixed methods study.

The World Health Organization recommends the scale-up of tuberculosis preventive therapy (TPT) for persons at risk of developing active tuberculosis (TB) as a key component to end the global TB epidemic. We sought to determine the feasibility of integrating testing for latent TB infection (LTBI) using interferon-gamma release assays (IGRAs) into the provision of TPT in a resource-limited high TB burden setting. We conducted a parallel convergent mixed methods study at four tertiary referral hospitals. We abstracted details of patients with bacteriologically confirmed pulmonary tuberculosis (PBC TB). We line-listed household contacts (HHCs) of these patients and carried out home visits where we collected demographic data from HHCs, and tested them for both HIV and LTBI. We performed multi-level Poisson regression with robust standard errors to determine the associations between the presence of LTBI and characteristics of HHCs. Qualitative data was collected from health workers and analyzed using inductive thematic analysis. From February to December 2020 we identified 355 HHCs of 86 index TB patients. Among these HHCs, uptake for the IGRA test was 352/355 (99%) while acceptability was 337/352 (95.7%). Of the 352 HHCs that were tested with IGRA, the median age was 18 years (IQR 10-32), 191 (54%) were female and 11 (3%) were HIV positive. A total of 115/352 (32.7%) had a positive IGRA result. Among HHCs who tested negative on IGRA at the initial visit, 146 were retested after 9 months and 5 (3.4%) of these tested positive for LTBI. At multivariable analysis, being aged ≥ 45 years [PR 2.28 (95% CI 1.02, 5.08)], being employed as a casual labourer [PR 1.38 (95% CI 1.19, 1.61)], spending time with the index TB patient every day [PR 2.14 (95% CI 1.51, 3.04)], being a parent/sibling to the index TB patients [PR 1.39 (95% CI 1.21, 1.60)] and sharing the same room with the index TB patients [PR 1.98 (95% CI 1.52, 2.58)] were associated with LTBI. Implementation challenges included high levels of TB stigma and difficulties in following strict protocols for blood sample storage and transportation. Integrating home-based IGRA testing for LTBI into provision of TB preventive therapy in routine care settings was feasible and resulted in high uptake and acceptability of IGRA tests.

Knowledge, attitude and practice of community pharmacy personnel in tuberculosis patient detection: a multicentre cross-sectional study in a high-burden tuberculosis setting

IntroductionControl of tuberculosis (TB) is hampered by suboptimal case detection and subsequent delays in treatment, which is worsened by the COVID-19 pandemic. The community pharmacy is reported as the place...

Tuberculosis screening improves preventive therapy uptake (TB SCRIPT) trial among people living with HIV in Uganda: a study protocol of an individual randomized controlled trial

BackgroundPeople living with HIV (PLHIV) have an increased risk of developing active tuberculosis (TB). To reduce the burden of TB among PLHIV, the World Health Organization (WHO) recommends systematic TB screening followed by (1) confirmatory TB testing for all who screen positive and (2) TB preventive therapy (TPT) for all TPT-eligible PLHIV who screen negative. Symptom-based screening remains the standard of care in most high TB burden settings, including Uganda. Despite having high sensitivity for active TB among antiretroviral-naïve PLHIV, symptom screening has poor specificity; as such, many high-risk PLHIV without active TB are not referred for TPT. C-reactive protein (CRP) is a promising alternative strategy for TB screening that has comparable sensitivity and higher specificity than symptom screening, and was endorsed by WHO in 2021. However, the impact of CRP-based TB screening on TB burden for PLHIV remains unclear.MethodsTB SCRIPT (TB Screening Improves Preventive Therapy Uptake) is a phase 3, multi-center, single-blinded, individual (1:1) randomized controlled trial evaluating the effectiveness of CRP-based TB screening on clinical outcomes of PLHIV. The trial aims to compare the effectiveness of a TB screening strategy based on CRP levels using a point-of-care (POC) assay on 2-year TB incidence and all-cause mortality (composite primary trial endpoint) and prevalent TB case detection and uptake of TPT (intermediate outcomes), relative to symptom-based TB screening (current practice).DiscussionThis study will be critical to improving selection of eligible PLHIV for TPT and helping guide the scale-up and integration of TB screening and TPT activities. This work will enable the field to improve TB screening by removing barriers to TPT initiation among eligible PLHIV, and provide randomized evidence to inform and strengthen WHO guidelines.Trial registrationClinicalTrials.gov NCT04557176. Registered on September 21, 2020.

Whole-Genome Sequencing Has the Potential To Improve Treatment for Rifampicin-Resistant Tuberculosis in High-Burden Settings: a Retrospective Cohort Study.

ABSTRACTTreatment of multidrug-resistant or rifampicin-resistant tuberculosis (MDR/RR-TB), although improved in recent years with shorter, more tolerable regimens, remains largely standardized and based on limited drug susceptibility testing (DST). More individualized treatment with expanded DST access is likely to improve patient outcomes. To assess the potential of TB drug resistance prediction based on whole-genome sequencing (WGS) to provide more effective treatment regimens, we applied current South African treatment recommendations to a retrospective cohort of MDR/RR-TB patients from Khayelitsha, Cape Town. Routine DST and clinical data were used to retrospectively categorize patients into a recommended regimen, either a standardized short regimen or a longer individualized regimen. Potential regimen changes were then described with the addition of WGS-derived DST. WGS data were available for 1274 MDR/RR-TB patient treatment episodes across 2008 to 2017. Among 834 patients initially eligible for the shorter regimen, 385 (46%) may have benefited from reduced drug dosage or removing ineffective drugs when WGS data were considered. A further 187 (22%) patients may have benefited from more effective adjusted regimens. Among 440 patients initially eligible for a longer individualized regimen, 153 (35%) could have been switched to the short regimen. Overall, 305 (24%) patients had MDR/RR-TB with second-line TB drug resistance, where the availability of WGS-derived DST would have allowed more effective treatment individualization. These data suggest considerable benefits could accrue from routine access to WGS-derived resistance prediction. Advances in culture-free sequencing and expansion of the reference resistance mutation catalogue will increase the utility of WGS resistance prediction.

Transmission Of Tuberculosis Among illicit drug use Linkages (TOTAL): A cross-sectional observational study protocol using respondent driven sampling.

People who use illicit drugs (PWUDs) have been identified as a key at-risk group for tuberculosis (TB). Examination of illicit drug use networks has potential to assess the risk of TB exposure and disease progression. Research also is needed to assess mechanisms for accelerated TB transmission in this population. This study aims to 1) assess the rate of TB exposure, risk of disease progression, and disease burden among PWUD; 2) estimate the proportion of active TB cases resulting from recent transmission within this network; and 3) evaluate whether PWUD with TB disease have physiologic characteristics associated with more efficient TB transmission. Our cross-sectional, observational study aims to assess TB transmission through illicit drug use networks, focusing on methamphetamine and Mandrax (methaqualone) use, in a high TB burden setting and identify mechanisms underlying accelerated transmission. We will recruit and enroll 750 PWUD (living with and without HIV) through respondent driven sampling in Worcester, South Africa. Drug use will be measured through self-report and biological measures, with sputum specimens collected to identify TB disease by Xpert Ultra (Cepheid) and mycobacterial culture. We will co-enroll those with microbiologic evidence of TB disease in Aim 2 for molecular and social network study. Whole genome sequencing of Mycobacteria tuberculosis (Mtb) specimens and social contact surveys will be done for those diagnosed with TB. For Aim 3, aerosolized Mtb will be compared in individuals with newly diagnosed TB who do and do not smoke illicit drug. Knowledge from this study will provide the basis for a strategy to interrupt TB transmission in PWUD and provide insight into how this fuels overall community transmission. Results have potential for informing interventions to reduce TB spread applicable to high TB and HIV burden settings. Trial registration: Clinicaltrials.gov Registration Number: NCT041515602. Date of Registration: 5 November 2019.

Development of active tuberculosis in patients treated with biological disease-modifying antirheumatic drugs

Background. Biological disease-modifying antirheumatic drugs (bDMARDs) have been shown to be highly effective in the treatment of rheumatic conditions, but may increase the risk of infections. Development of tuberculosis (TB) while on bDMARD therapy is of particular concern in high TB burden settings such as Western Cape Province, South Africa. Objectives. To describe the diagnosis, management and outcome of patients who developed active TB while receiving a bDMARD. Results. Ten patients who screened negative for TB prior to initiation of a bDMARD subsequently developed active TB. TB was diagnosed between 10 months and 9 years from bDMARD initiation, suggesting new infection, and included 6 cases of extrapulmonary TB. All patients required multiple tests to confirm the diagnosis of TB, and all were successfully treated. Conclusions. TB can occur in patients on bDMARD therapy despite initial screening, and may have unusual, extrapulmonary manifestations that pose a diagnostic challenge.

Use of integrase inhibitors in HIV-associated tuberculosis in high-burden settings: implementation challenges and research gaps.

People living with HIV have a higher risk of developing tuberculosis, and tuberculosis is one of the leading causes of death among people living with HIV globally. Treating HIV and tuberculosis concurrently has morbidity and mortality benefits. However, HIV and tuberculosis co-treatment is challenging due to drug-drug interactions, overlapping toxicities, tuberculosis-associated immune reconstitution syndrome, and concerns for treatment failure or drug resistance. Drug-drug interactions between antiretrovirals and tuberculosis drugs are driven mainly by the rifamycins (for example, the first-line tuberculosis drug rifampicin), and dose adjustments or drug switches during co-treatment are commonly required. Several implementation challenges and research gaps exist when combining the integrase strand transfer inhibitors (INSTIs), highly potent antiretroviral drugs recommended as first-line treatment of HIV, and drugs used for the treatment and prevention of tuberculosis. Ongoing and planned studies will address some critical questions on the use of INSTIs in settings with a high tuberculosis burden, including dosing of dolutegravir, bictegravir, and cabotegravir when used with the rifamycins for both tuberculosis treatment and prevention. Failure, in the past, to include people with tuberculosis in HIV clinical treatment trials has been responsible for some of the research gaps still evident for informing optimisation of HIV and tuberculosis co-treatment.

Spatially targeted digital chest radiography to reduce tuberculosis in high-burden settings: A study of adaptive decision making

BackgroundSpatially-targeted approaches to screen for tuberculosis (TB) could accelerate TB control in high-burden populations. We aimed to estimate gains in case-finding yield under an adaptive decision-making approach for spatially-targeted, mobile digital chest radiography (dCXR)-based screening in communities with varying levels of TB prevalence. MethodsWe used a Monte-Carlo simulation model to simulate a spatially-targeted screening intervention in 24 communities with TB prevalence estimates derived from a large community-randomized trial. We implemented a Thompson sampling algorithm to allocate screening units based on Bayesian probabilities of local TB prevalence that are continuously updated during weekly screening rounds. Four mobile units for dCXR-based screening and subsequent Xpert Ultra-based testing were allocated among the communities during a 52-week period. We estimated the yield of bacteriologically-confirmed TB per 1000 screenings comparing scenarios of spatially-targeted and untargeted resource allocation. ResultsWe estimated that under the untargeted scenario, an expected 666 (95% uncertainty interval 522–825) TB cases would be detected over one year, equivalent to 8.9 (7.5–10.3) per 1000 individuals screened. Allocating the screening units to the communities with the highest (prior-year) cases notification rates resulted in an expected 760 (617−926) TB cases detected, 10.1 (8.6–11.8) per 1000 screened. Adaptive, spatially-targeted screening resulted in an expected 1241 (995–1502) TB cases detected, 16.5 (14.5–18.7) per 1000 screened. Numbers of dCXR-based screenings needed to detect one additional TB case declined during the first 12–14 weeks as a result of Bayesian learning. ConclusionWe introduce a spatially-targeted screening strategy that could reduce the number of screenings necessary to detect additional TB in high-burden settings and thus improve the efficiency of screening interventions. Empirical trials are needed to determine whether this approach could be successfully implemented.