An epidemiological analysis of TB trends in native and migrant populations, New Mexico, 1993-2021.

To analyze the epidemiological, demographic, clinical, laboratory, radiographic and treatment outcome trends in non-US-born individuals with TB in New Mexico.We retrospectively analyzed TB data from New Mexico TB surveillance system from (1993-2021), comparing variables between non-US-born and US-born individuals.Of the 1,512 TB cases, 876 (56.5%) were non-US-born and 653 (43.3%) were US-born. The incidence rate among non-US-born patients declined from 15.3/100,000 (1993) to 7.8/100,000 (2021) (54.6% reduction), while among US-born patients it declined from 3.3/100,000 (1993) to 0.5/100,000 (2021) (84.8% reduction). The majority of non-US-born individuals were from Mexico (n = 482, 73.5%). Non-US-born were typically younger adults (median age: 54 vs. 61), predominantly male (64.8% vs. 59.4%), less likely to consume excess alcohol and have extrapulmonary TB. However, they were more likely to exhibit resistance to standard TB drugs (P < 0.01). Non-US-born individuals were less likely to die (7.8% vs. 15.4%), but more likely to be lost to follow-up (P < 0.007). Treatment by providers outside the Department of Health was associated with noncompletion (OR 0.18, 95% CI 0.09-0.35; P < 0.001).These results highlight the need for a detailed understanding of the impact of migration on TB epidemiology and the development of tailored interventions to improve treatment outcomes..

Opinion review of drug resistant tuberculosis in West Africa: tackling the challenges for effective control.

Drug-resistant (DR) tuberculosis (TB) is a major public health concern globally, complicating TB control and management efforts. West Africa has historically faced difficulty in combating DR-TB due to limited diagnostic skills, insufficient access to excellent healthcare, and ineffective healthcare systems. This has aided in the emergence and dissemination of DR Mycobacterium tuberculosis complex (MTBC) strains in the region. In the past, DR-TB patients faced insufficient resources, fragmented efforts, and suboptimal treatment outcomes. However, current efforts to combat DR-TB in the region are promising. These efforts include strengthening diagnostic capacities, improving access to quality healthcare services, and implementing evidence-based treatment regimens for DR-TB. Additionally, many West African National TB control programs are collaborating with international partners to scale up laboratory infrastructure, enhance surveillance systems, and promote infection control measures. Moreso, novel TB drugs and regimens, such as bedaquiline and delamanid, are being introduced to improve treatment outcomes for DR-TB cases. Despite these obstacles, there is optimism for the future of DR-TB control in West Africa. Investments are being made to improve healthcare systems, expand laboratory capacity, and support TB research and innovation. West African institutions are now supporting knowledge sharing, capacity building, and resource mobilization through collaborative initiatives such as the West African Network for TB, AIDS, and Malaria (WANETAM), the West African Health Organization (WAHO), and other regional or global partners. These efforts hold promise for improved diagnostics, optimized treatment regimens, and provide better patient outcomes in the future where drug-resistant TB in WA can be effectively controlled, reducing the burden of the disease, and improving the health outcomes of affected individuals.

Progress Toward Tuberculosis Elimination and Tuberculosis Program Performance - National Tuberculosis Indicators Project, 2016-2022.

Problem/Condition: Elimination of tuberculosis (TB) is defined as reducing TB disease incidence in the United States to less than 1 case per million persons per year. In 2022, TB incidence in the United States was 2.5 TB cases per 100,000 persons. CDC's TB program developed a set of national TB indicators to evaluate progress toward TB elimination through monitoring performance of state and city TB program activities. Examining TB indicator data enables state- and city-level TB programs to identify areas for program evaluation and improvement activities. These data also help CDC identify states and cities that might benefit from technical assistance. Period Covered: The 5-year period for which the most recent data were available for each of five indicators: 1) overall TB incidence (2018-2022), 2) TB incidence among non-U.S.-born persons (2018-2022), 3) percentage of persons with drug susceptibility results reported (2018-2022), 4) percentage of contacts to sputum acid-fast bacillus (AFB) smear-positive TB patients with newly diagnosed latent TB infection (LTBI) who completed treatment (2017-2021), and 5) percentage of patients with completion of TB therapy within 12 months (2016-2020). Description of System: The National TB Indicators Project (NTIP) is a web-based performance monitoring tool that uses national TB surveillance data reported through the National TB Surveillance System and the Aggregate Reports for TB Program Evaluation. NTIP was developed to facilitate the use of existing data to help TB program staff members prioritize activities, monitor progress, and focus program improvement efforts. The following five indicators were selected for this report because of their importance in Federal TB funding allocation and in accelerating the decline in TB cases: 1) overall TB incidence in the United States, 2) TB incidence among non-U.S.-born persons, 3) percentage of persons with drug susceptibility results reported, 4) percentage of contacts to sputum AFB smear-positive TB cases who completed treatment for LTBI, and 5) percentage of patients with completion of TB therapy within 12 months. For this report, 52 TB programs (50 states, the District of Columbia, and New York City) were categorized into terciles based on the 5-year average number of TB cases reported to National TB Surveillance System. This grouping allows comparison of TB programs that have similar numbers of TB cases and allocates a similar number of TB programs to each category. The following formula was used to calculate the relative change by TB program for each indicator: [(% from year 5 - % from year 1 ÷ % from year 1) × 100]. Results: During the 5-year period for which the most recent data were available, most TB programs had improvements in reducing overall TB incidence (71.2%) and increasing the percentage of contacts receiving a diagnosis of LTBI who completed LTBI treatment (55.8%); the majority of programs (51.0%) also had improvements in reducing incidence among non-U.S.-born persons. The average percentage of persons with drug susceptibility results reported in most jurisdictions (28 of 52, [53.9%]) met or exceeded the 5-year national average of 97% (2018-2022). The percentage of contacts to sputum acid-fast bacillus (AFB) smear-positive TB patients with newly diagnosed latent TB infection (LTBI) who completed treatment increased in 29 of 52 (55.8%) jurisdictions from 2017 to 2021, signifying that, for most jurisdictions, steps have been taken to enhance performance in this area. The average percentage of patients with completion of TB therapy within 12 months was at or above the national average of 89.7% in approximately two-thirds (32 of 52 [61.5%]) of jurisdictions. Interpretation: This report is the first to describe a 5-year relative change for TB program performance. These results suggest that TB programs are making improvements in activities that help identify persons with TB and LTBI and ensure patients complete treatment in a timely manner. Public Health Action: Use of NTIP data from individual TB programs enables a more detailed examination of trends in program performance and identification of areas for program improvement. Assessing indicator trends by TB program provides an opportunity to gain a better understanding of program performance in comparison to other programs. It can also facilitate communication between programs regarding successes and challenges in program improvement. This information is valuable for TB programs to allocate resources effectively and provide additional context on TB control for public health policymakers.

Tuberculous Paraplegia: Outcome of Operative Intervention.

BACKGROUND: Tuberculosis of the spine, a common manifestation of extra-pulmonary tuberculosis is characterized by vertebral destruction, paradiscal involvement, abscess collection and varying degrees of neurologic affectation. The primary disease caused by mycobacterium tuberculosis complex infects the lungs, lymph nodes of the mediastinum and gastrointestinal tract/ viscera with spinal involvement being secondary and caused by haematogenous spread. Tuberculous paraplegia arises as a complication of spinal involvement. AIM: To determine the outcome of operative intervention in tuberculous paraplegia. Methodology: This was a retrospective study involving 10 patients with tuberculous spinal involvement with varying degrees of neurological deficit as defined by both Tuli and ASIA grading. The VAS score, ESR, ASIA grade (both pre-op and post op), Tuli's grade (pre-op and post op) were used to analyze the therapeutic effects of the surgery. RESULTS: The mean pre-operative VAS score was 5.9 ±1.8, which significantly decreased to 2.2 ±1.3 six weeks post operatively. The mean pre-operative ESR and CRP was 78.9 ± 11.3mm/hr and 83 ± 13.5 respectively; which both showed a statistically significant decrease post-operatively, p<0.05. All cases achieved an increase of more than one ASIA grade post-operatively. CONCLUSION: Early surgical intervention is beneficial in patients with tuberculous spinal disease with neurologic involvement.

Current landscape of exosomes in tuberculosis development, diagnosis, and treatment applications.

Tuberculosis (TB), caused by the bacterial pathogen Mycobacterium tuberculosis (MTB), remains one of the most prevalent and deadly infectious diseases worldwide. Currently, there are complex interactions between host cells and pathogens in TB. The onset, progression, and regression of TB are correlated not only with the virulence of MTB but also with the immunity of TB patients. Exosomes are cell-secreted membrane-bound nanovesicles with lipid bilayers that contain a variety of biomolecules, such as metabolites, lipids, proteins, and nucleic acids. Exosome-mediated cell-cell communication and interactions with the microenvironment represent crucial mechanisms through which exosomes exert their functional effects. Exosomes harbor a wide range of regulatory roles in physiological and pathological conditions, including MTB infection. Exosomes can regulate the immune response, metabolism, and cellular death to remodel the progression of MTB infection. During MTB infection, exosomes display distinctive profiles and quantities that may act as diagnostic biomarkers, suggesting that exosomes provide a revealing glimpse into the evolving landscape of MTB infections. Furthermore, exosomes derived from MTB and mesenchymal stem cells can be harnessed as vaccine platforms and drug delivery vehicles for the precise targeting and treatment of TB. In this review, we highlight the functions and mechanisms through which exosomes influence the progression of TB. Additionally, we unravel the critical significance of exosomal constituents in the diagnosis and therapeutic applications of TB, aiming to offer novel perspectives and strategies for combating TB.

Tuberculous ciliary body granuloma initially diagnosed as bullous retinal detachment: a case report.

BACKGROUND: Ocular tuberculosis is a relatively rare extrapulmonary manifestation of tuberculosis. This vision-threatening disease is extremely challenging to diagnose, particularly because it can mimic other diseases. We report a case of tuberculous ciliary body granuloma initially diagnosed as bullous retinal detachment. CASE REPORT: A 52-year-old female presented with bullous retinal detachment in her left eye, and ultrasound biomicroscopy (UBM) verified the presence of a lesion with ciliary body granulomatous inflammation. The T-SPOT was positive, and the purified protein derivative (PPD) test was strongly positive (diameter of 20 mm). Following the administration of oral anti-tuberculosis regimen combined with prednisone, the retina gradually became reattached, the ciliary body granuloma became significantly reduced in size, and the visual acuity of the patient noticeably improved. CONCLUSIONS: Tuberculous ciliary body granulomas can cause bullous exudative retinal detachment and can be diagnosed with UBM. Early and full-course anti-tuberculosis treatment (ATT) combined with corticosteroid therapy can improve the patient prognosis.

Promising Ursolic Acid as a Novel Antituberculosis Agent: Current Progress and Challenges.

Tuberculosis (TB) stands as the second most prevalent cause of global human mortality from infectious diseases. In 2022, the World Health Organization documented an estimated number of global TB cases reaching 7.5 million, which causes death for 1.13 million patients. The continuous growth of drug-resistant TB cases due to various mutations in the Mycobacterium tuberculosis (MTB) strain, raises the urgency of the exploration of novel anti-TB treatments. Ursolic acid (UA) is a natural pentacyclic triterpene found in various plants that has shown potential as a novel anti-TB agent. This review aims to provide an overview of the therapeutic prospects of UA against MTB, with a particular emphasis on in silico, in vitro, and in vivo studies. Various mechanisms of action of UA against MTB are briefly recapped from in silico studies, such as enoyl acyl carrier protein reductase inhibitors, FadA5 (Acetyl-CoA acetyltransferase) inhibitors, tuberculosinyl adenosine transferase inhibitors, and small heat shock protein 16.3 inhibitor. The potential of UA to overcome drug resistance and its synergistic effects with existing antituberculosis drugs are briefly explained from in vitro studies using a variety of methods, such as Microplate Alamar Blue Assay, Mycobacteria Growth Indicator Tube 960 and Resazurin Assays, morphological change evaluation using transmission electron microscopy, and in vivo studies using BALB/C infected with multi drug resistant clinical isolates. Besides its promising mechanism as an antituberculosis drug, its complex chemical composition, limited availability and supply, and lack of intellectual property are also reviewed as those are the most frequently occurring challenges that need to be addressed for the successful development of UA as novel anti-TB agent.

Joint clinical determinants for bivariate hematological parameter among TB/HIV co-infected adults under TB/HIV treatment in university of Gondar comprehensive specialized hospital: Retrospective panel data study.

BACKGROUND: Worldwide ranking above HIV/AIDS, tuberculosis is continues to have a significant effect on public health and the leading cause of death due to high progression of HIV. The objective of current study was identify joint clinical determinants that affecting bivariate hematological parameter among TB/HIV co-infected adults under TB/HIV treatment in university of Gondar comprehensive specialized hospital. METHOD: The result of these study was conducted at university of Gondar comprehensive specialized hospital, Gondar, Ethiopia by using a retrospective cohort follow up study from September 2015-march 2022 G.C. The source of data in this study was secondary data obtained from patients chart. Bayesian approach of longitudinal linear mixed effect sub model was used in panel data set to get wide range of information about TB/HIV co-infected patients. RESULT: Out of 148 co-infected participants more than half of the patients (56.1%) and (52.7%) accounted for CPT and INH non users, of which 10.8% and 10.3% had the outcome of mortality respectively. The random intercept and slope model were selected for repeated measure hemoglobin level and hematocrit based on deviance information criteria (DIC), and probability of direction (Pd) under the full model. CONCLUSION: Current study revealed that clinical predictors red blood cell count, platelet cell count, fair and good treatment adherence, other ART regiment, IPT drug users, and viral load count < 10,000 copies/mL, were associated with high hemoglobin level concentration while, lymphocyte count, WHO clinical stage-IV,1e ART regiment, and patients with OIs results for low hemoglobin level concentration. Likewise, red blood cell count, platelet cell count, fair and good treatment adherence, IPT drug users, and viral load count < 10,000 copies/mL co-infected patients had high hematocrit, while lymphocyte count, WHO clinical stage-III,1c ART regiment, and patients with OIs significantly leads to low hematocrit. Health professionals give more attention to these important predictors to reduce progression of disease when the co-infected patients come back again in the hospital. In addition, health staff should conduct health related education for individuals to examine continuous check-up of co-infected patients.

The introduction of video-enabled directly observed therapy (video-DOT) for patients with drug-resistant TB disease in Eswatini amid the COVID-19 pandemic - a retrospective cohort study.

BACKGROUND: Video-enabled directly observed therapy (video-DOT) has been proposed as an additional option for treatment provision besides in-person DOT for patients with drug-resistant TB (DRTB) disease. However, evidence and implementation experience mainly originate from well-resourced contexts. This study describes the operationalization of video-DOT in a low-resourced setting in Eswatini facing a high burden of HIV and TB amid the emergence of the COVID-19 pandemic. METHODS: This is a retrospectively established cohort of patients receiving DRTB treatment during the implementation of video-DOT in Shiselweni from May 2020 to March 2022. We described intervention uptake (vs. in-person DOT) and assessed unfavorable DRTB treatment outcome (death, loss to care) using Kaplan-Meier statistics and multivariable Cox-regression models. Video-related statistics were described with frequencies and medians. We calculated the fraction of expected doses observed (FEDO) under video-DOT and assessed associations with missed video uploads using multivariable Poisson regression analysis. RESULTS: Of 71 DRTB patients eligible for video-DOT, the median age was 39 (IQR 30-54) years, 31.0% (n = 22) were women, 67.1% (n = 47/70) were HIV-positive, and 42.3% (n = 30) were already receiving DRTB treatment when video-DOT became available. About half of the patients (n = 37; 52.1%) chose video-DOT, mostly during the time when COVID-19 appeared in Eswatini. Video-DOT initiations were lower in new DRTB patients (aHR 0.24, 95% CI 0.12-0.48) and those aged ≥ 60 years (aHR 0.27, 95% CI 0.08-0.89). Overall, 20,634 videos were uploaded with a median number of 553 (IQR 309-748) videos per patient and a median FEDO of 92% (IQR 84-97%). Patients aged ≥ 60 years were less likely to miss video uploads (aIRR 0.07, 95% CI 0.01-0.51). The cumulative Kaplan-Meier estimate of an unfavorable treatment outcome among all patients was 0.08 (95% CI 0.03-0.19), with no differences detected by DOT approach and other baseline factors in multivariable analysis. CONCLUSIONS: Implementing video-DOT for monitoring of DRTB care provision amid the intersection of the HIV and COVID-19 pandemics seemed feasible. Digital health technologies provide additional options for patients to choose their preferred way to support treatment taking, thus possibly increasing patient-centered health care while sustaining favorable treatment outcomes.

Assessment of Isoniazid Preventive Therapy and Incidence of Tuberculosis among People Living with Human Immunodeficiency Virus Seeking Care in an Anti-retroviral Therapy Center, Puducherry.

BACKGROUND: One in three deaths among people living with human immunodeficiency virus (PLHIV) is due to Tuberculosis. Isoniazid preventive therapy (IPT) was implemented in antiretroviral therapy (ART) center Puducherry in July 2017. OBJECTIVES: We have determined the proportion of PLHIV who were eligible, initiated, completed IPT and also the incidence of tuberculosis before and after implementation of IPT. MATERIALS AND METHODS: It was a facility based longitudinal descriptive study. All PLHIV, aged 10 years and above, seeking care in ART Centers was included. The number of PLHIV eligible, initiated and completed IPT was summarized as proportion with 95% CI. RESULTS: Among the registered PLHIV (999), the proportion of PLHIV those were found eligible for IPT was 93% [95% CI (91.24%-94.67%)] and initiated on IPT was 92% [95% CI (90.20%-93.95%)]. Completion rate of IPT was 96.3% [95% CI (94.59%-97.63%)]. CONCLUSION: Initiation of IPT was relatively less among newly registered PLHIV as compared to older cohort of PLHIV.

Testing novel strategies for patients hospitalised with HIV-associated disseminated tuberculosis (NewStrat-TB): protocol for a randomised controlled trial.

BACKGROUND: HIV-associated tuberculosis (TB) contributes disproportionately to global tuberculosis mortality. Patients hospitalised at the time of the diagnosis of HIV-associated disseminated TB are typically severely ill and have a high mortality risk despite initiation of tuberculosis treatment. The objective of the study is to assess the safety and efficacy of both intensified TB treatment (high dose rifampicin plus levofloxacin) and immunomodulation with corticosteroids as interventions to reduce early mortality in hospitalised patients with HIV-associated disseminated TB. METHODS: This is a phase III randomised controlled superiority trial, evaluating two interventions in a 2 × 2 factorial design: (1) high dose rifampicin (35 mg/kg/day) plus levofloxacin added to standard TB treatment for the first 14 days versus standard tuberculosis treatment and (2) adjunctive corticosteroids (prednisone 1.5 mg/kg/day) versus identical placebo for the first 14 days of TB treatment. The study population is HIV-positive patients diagnosed with disseminated TB (defined as being positive by at least one of the following assays: urine Alere LAM, urine Xpert MTB/RIF Ultra or blood Xpert MTB/RIF Ultra) during a hospital admission. The primary endpoint is all-cause mortality at 12 weeks comparing, first, patients receiving intensified TB treatment to standard of care and, second, patients receiving corticosteroids to those receiving placebo. Analysis of the primary endpoint will be by intention to treat. Secondary endpoints include all-cause mortality at 2 and 24 weeks. Safety and tolerability endpoints include hepatoxicity evaluations and corticosteroid-related adverse events. DISCUSSION: Disseminated TB is characterised by a high mycobacterial load and patients are often critically ill at presentation, with features of sepsis, which carries a high mortality risk. Interventions that reduce this high mycobacterial load or modulate associated immune activation could potentially reduce mortality. If found to be safe and effective, the interventions being evaluated in this trial could be easily implemented in clinical practice. TRIAL REGISTRATION: ClinicalTrials.gov NCT04951986. Registered on 7 July 2021 https://clinicaltrials.gov/study/NCT04951986.

Effectiveness and cost-effectiveness of community-based directly observed treatment (DOT) versus health facility-based DOT of tuberculosis in Africa: protocol for a systematic review and meta-analysis.

BACKGROUND: Tuberculosis (TB) remains a significant global health challenge, especially prevalent in the WHO African region. The WHO's End TB Strategy emphasises effective treatment approaches such as directly observed therapy (DOT), yet the optimal implementation of DOT, whether through health facility-based (HF DOT) or community-based (CB DOT) approaches, remains uncertain. OBJECTIVE: To conduct a systematic comparison of the effectiveness and cost-effectiveness of Community-Based Directly Observed Treatment (CB DOT) versus Health Facility-Based Directly Observed Treatment (HF DOT) for tuberculosis (TB) treatment in African settings. METHODS: We will conduct a systematic review and meta-analysis following Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guidelines. We will search PubMed, Embase, Web of Science, Scopus and the Cochrane Library for articles published up to 30 March 2023, without date restrictions. Eligible studies must be full economic evaluations conducted in African countries, comparing CB DOT to HF DOT regarding treatment outcomes and costs. Exclusion criteria include non-English, non-peer-reviewed or studies lacking caregiver involvement in CB DOT, health facility-based DOT comparison, direct comparability between CB DOT and HF DOT, significant selection bias or non-economic evaluations. Data extraction will be performed independently by reviewers, and meta-analyses will use STATA software. To pool the data, a random-effect model will be applied, and quality assessment of the studies will be conducted. ETHICS AND DISSEMINATION: Ethical approval is not required as the study will use previously published articles available publicly. Findings will be presented at international and national conferences and published in open-access, peer-reviewed journals. PROSPERO REGISTRATION NUMBER: CRD42023443260.

Sputum culture reversion in longer treatments with bedaquiline, delamanid, and repurposed drugs for drug-resistant tuberculosis.

Sputum culture reversion after conversion is an indicator of tuberculosis (TB) treatment failure. We analyze data from the endTB multi-country prospective observational cohort (NCT03259269) to estimate the frequency (primary endpoint) among individuals receiving a longer (18-to-20 month) regimen for multidrug- or rifampicin-resistant (MDR/RR) TB who experienced culture conversion. We also conduct Cox proportional hazard regression analyses to identify factors associated with reversion, including comorbidities, previous treatment, cavitary disease at conversion, low body mass index (BMI) at conversion, time to conversion, and number of likely-effective drugs. Of 1,286 patients, 54 (4.2%) experienced reversion, a median of 173 days (97-306) after conversion. Cavitary disease, BMI < 18.5, hepatitis C, prior treatment with second-line drugs, and longer time to initial culture conversion were positively associated with reversion. Reversion was uncommon. Those with cavitary disease, low BMI, hepatitis C, prior treatment with second-line drugs, and in whom culture conversion is delayed may benefit from close monitoring following conversion.

Prevalence, drug resistance, and genotypic diversity of the RDRio subfamily of Mycobacterium tuberculosis in Ecuador: a retrospective analysis for years 2012-2016.

Introduction: A major sublineage within the Mycobacterium tuberculosis (MTB) LAM family characterized by a new in-frame fusion gene Rv3346c/55c was discovered in Rio de Janeiro (Brazil) in 2007, called RDRio, associated to drug resistance. The few studies about prevalence of MTB RDRio strains in Latin America reported values ranging from 3% in Chile to 69.8% in Venezuela, although no information is available for countries like Ecuador. Methods: A total of 814 MTB isolates from years 2012 to 2016 were screened by multiplex PCR for RDRio identification, followed by 24-loci MIRU-VNTR and spoligotyping. Results: A total number of 17 MTB RDRio strains were identified, representing an overall prevalence of 2.09% among MTB strains in Ecuador. While 10.9% of the MTB isolates included in the study were multidrug resistance (MDR), 29.4% (5/17) of the RDRio strains were MDR. Discussion: This is the first report of the prevalence of MTB RDRio in Ecuador, where a strong association with MDR was found, but also a very low prevalence compared to other countries in Latin America. It is important to improve molecular epidemiology tools as a part of MTB surveillance programs in Latin America to track the transmission of potentially dangerous MTB stains associated to MDR TB like MTB RDRio.

Subclinical tuberculosis: a meta-analysis of prevalence and scoping review of definitions, prevalence and clinical characteristics.

BACKGROUND: This scoping review aimed to characterise definitions used to describe subclinical tuberculosis (TB), estimate the prevalence in different populations and describe the clinical characteristics and treatment outcomes in the scientific literature. METHODS: A systematic literature search was conducted using PubMed. We included studies published in English between January 1990 and August 2022 that defined "subclinical" or "asymptomatic" pulmonary TB disease, regardless of age, HIV status and comorbidities. We estimated the weighted pooled proportions of subclinical TB using a random-effects model by World Health Organization reported TB incidence, populations and settings. We also pooled the proportion of subclinical TB according to definitions described in published prevalence surveys. RESULTS: We identified 29 prevalence surveys and 71 other studies. Prevalence survey data (2002-2022) using "absence of cough of any duration" criteria reported higher subclinical TB prevalence than those using the stricter "completely asymptomatic" threshold. Prevalence estimates overlap in studies using other symptoms and cough duration. Subclinical TB in studies was commonly defined as asymptomatic TB disease. Higher prevalence was reported in high TB burden areas, community settings and immunocompetent populations. People with subclinical TB showed less extensive radiographic abnormalities, higher treatment success rates and lower mortality, although studies were few. CONCLUSION: A substantial proportion of TB is subclinical. However, prevalence estimates were highly heterogeneous between settings. Most published studies incompletely characterised the phenotype of people with subclinical TB. Standardised definitions and diagnostic criteria are needed to characterise this phenotype. Further research is required to enhance case finding, screening, diagnostics and treatment options for subclinical TB.

Prevalence and genetic basis of Mycobacterium tuberculosis resistance to pretomanid in China.

BACKGROUND: Pretomanid is a key component of new regimens for the treatment of drug-resistant tuberculosis (TB) which are being rolled out globally. However, there is limited information on the prevalence of pre-existing resistance to the drug. METHODS: To investigate pretomanid resistance rates in China and its underlying genetic basis, as well as to generate additional minimum inhibitory concentration (MIC) data for epidemiological cutoff (ECOFF)/breakpoint setting, we performed MIC determinations in the Mycobacterial Growth Indicator Tube™ (MGIT) system, followed by WGS analysis, on 475 Mycobacterium tuberculosis (MTB) isolated from Chinese TB patients between 2013 and 2020. RESULTS: We observed a pretomanid MIC distribution with a 99% ECOFF equal to 0.5 mg/L. Of the 15 isolates with MIC values > 0.5 mg/L, one (MIC = 1 mg/L) was identified as MTB lineage 1 (L1), a genotype previously reported to be intrinsically less susceptible to pretomanid, two were borderline resistant (MIC = 2-4 mg/L) and the remaining 12 isolates were highly resistant (MIC ≥ 16 mg/L) to the drug. Five resistant isolates did not harbor mutations in the known pretomanid resistant genes. CONCLUSIONS: Our results further support a breakpoint of 0.5 mg/L for a non-L1 MTB population, which is characteristic of China. Further, our data point to an unexpected high (14/475, 3%) pre-existing pretomanid resistance rate in the country, as well as to the existence of yet-to-be-discovered pretomanid resistance genes.