Estimating the future burden of multidrug-resistant and extensively drug-resistant tuberculosis in India, the Philippines, Russia, and South Africa: a mathematical modelling study

Tracking multidrug resistant tuberculosis: a 30-year analysis of global, regional, and national trends

Objectives

To provide valuable insights for targeted interventions and resource allocation, our analysis delved into the multifaceted burden, trends, risks, and projections of multi drug resistant tuberculosis (MDR-TB).

Methods

This research employed data from the Global Burden of Disease (GBD) 2019 dataset, which used a comparative risk assessment to quantify the disease burden resulting from risk factors. Initially, this database was utilized to extract details concerning the disability-adjusted life years (DALYs), mortality, incidence, and the number of individuals afflicted by MDR-TB. Subsequently, regression analyses were conducted using the Joinpoint program to figure average annual percent change (AAPC) to ascertain the trend. Thirdly, the age-period-cohort model (APCM) was adopted to analyze evolutions in incidence and mortality. Finally, utilizing the Nordpred model within R software, we projected the incidence and mortality of MDR-TB from 2020 to 2030.

Results

MDR-TB remained a pressing global health concern in regions with lower socio-demographic indexes (SDI), where the AAPC in DALYs topped 7% from 1990 to 2019. In 2019, the cumulative DALYs attributed to MDR-TB tallied up to 4.2 million, with India, the Russian Federation, and China bearing the brunt. Notably, the incidence rates have shown a steadfast presence over the past decade, and a troubling forecast predicts an uptick in these areas from 2020 to 2030. Additionally, the risk of contracting MDR-TB grew with advancing age, manifesting most acutely among men aged 40+ in lower SDI regions. Strikingly, alcohol consumption had been identified as a significant contributor, surpassing the impacts of smoking and high fasting plasma glucose, leading to 0.7 million DALYs in 2019.

Conclusions

A robust strategy is needed to end tuberculosis (TB) by 2030, especially in lower SDI areas.

Association between HIV and acquisition of rifamycin resistance with first-line TB treatment: a systematic review and meta-analysis

BACKGROUND

Multi-drug or rifamycin-resistant tuberculosis (MDR/RR-TB) is an important public health concern, including in settings with high HIV prevalence. TB drug resistance can be directly transmitted or arise through resistance acquisition during first-line TB treatment. Limited evidence suggests that people living with HIV (PLHIV) might have an increased risk of acquired rifamycin-resistance (ARR).

METHODS

To assess HIV as a risk factor for ARR during first-line TB treatment, a systematic review and meta-analysis was conducted. ARR was defined as rifamycin-susceptibility at treatment start with rifamycin-resistance diagnosed during or at the end of treatment, or at recurrence. PubMed/MEDLINE, CINAHL, Cochrane Library, and Google Scholar databases were searched from inception to 23 May 2024 for articles in English; conference abstracts were also searched from 2004 to 2021. The Mantel-Haenszel random-effects model was used to estimate the pooled odds ratio of any association between HIV and ARR among individuals receiving first-line TB treatment.

RESULTS

Ten studies that included data collected between 1990 and 2014 were identified: five from the United States, two from South Africa and one each from Uganda, India and Moldova. A total of 97,564 individuals were included across all studies, with 13,359 (13.7%) PLHIV. Overall, 312 (0.32%) acquired rifamycin-resistance, among whom 115 (36.9%) were PLHIV. The weighted odds of ARR were 4.57 (95% CI, 2.01-10.42) times higher among PLHIV compared to HIV-negative individuals receiving first-line TB treatment.

CONCLUSION

The available data, suggest that PLHIV have an increased ARR risk during first-line TB treatment. Further research is needed to clarify specific risk factors, including advanced HIV disease and TB disease severity. Given the introduction of shorter, 4-month rifamycin-based regimens, there is an urgent need for additional data on ARR, particularly for PLHIV.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42022327337.

Mathematical models of drug-resistant tuberculosis lack bacterial heterogeneity: A systematic review

Drug-resistant tuberculosis (DR-TB) threatens progress in the control of TB. Mathematical models are increasingly being used to guide public health decisions on managing both antimicrobial resistance (AMR) and TB. It is important to consider bacterial heterogeneity in models as it can have consequences for predictions of resistance prevalence, which may affect decision-making. We conducted a systematic review of published mathematical models to determine the modelling landscape and to explore methods for including bacterial heterogeneity. Our first objective was to identify and analyse the general characteristics of mathematical models of DR-mycobacteria, including M. tuberculosis. The second objective was to analyse methods of including bacterial heterogeneity in these models. We had different definitions of heterogeneity depending on the model level. For between-host models of mycobacterium, heterogeneity was defined as any model where bacteria of the same resistance level were further differentiated. For bacterial population models, heterogeneity was defined as having multiple distinct resistant populations. The search was conducted following PRISMA guidelines in five databases, with studies included if they were mechanistic or simulation models of DR-mycobacteria. We identified 195 studies modelling DR-mycobacteria, with most being dynamic transmission models of non-treatment intervention impact in M. tuberculosis (n = 58). Studies were set in a limited number of specific countries, and 44% of models (n = 85) included only a single level of "multidrug-resistance (MDR)". Only 23 models (8 between-host) included any bacterial heterogeneity. Most of these also captured multiple antibiotic-resistant classes (n = 17), but six models included heterogeneity in bacterial populations resistant to a single antibiotic. Heterogeneity was usually represented by different fitness values for bacteria resistant to the same antibiotic (61%, n = 14). A large and growing body of mathematical models of DR-mycobacterium is being used to explore intervention impact to support policy as well as theoretical explorations of resistance dynamics. However, the majority lack bacterial heterogeneity, suggesting that important evolutionary effects may be missed.

Global adoption of 6-month drug-resistant TB regimens: Projected uptake by 2026

BACKGROUND

The WHO has issued a call to action urging countries to accelerate the rollout of new WHO-recommended shorter all-oral treatment regimens for drug-resistant TB (DR-TB), which remains a public-health crisis. The all-oral, 6-month BPaL/M regimen comprises 3-4 drugs: pretomanid used in combination with bedaquiline and linezolid, with or without moxifloxacin. This regimen has been recommended by the WHO for use in DR-TB patients instead of ≥9-month (up to 24-month) regimens. This study aims to project this regimen's use, along with its components bedaquiline, pretomanid and linezolid, and other treatments for DR-TB globally through 2026. It is intended to guide global health stakeholders in planning and budgeting for DR-TB interventions. Projected usage could help estimate cost of the individual components of DR-TB regimens over time.

METHODS

Semi-structured interviews were conducted with national TB programme participants in key countries to gather intelligence on established plans and targets for use of various DR-TB treatment regimens from 2023 to 2026. These data informed development of projections for the global use of regimens and drugs.

RESULTS

Consistent global growth in the use of shorter regimens in DR-TB treatment was shown: BPaLM reaching 126,792 patients, BPaL reaching 43,716 patients, and the 9-11-month all-oral bedaquiline-based regimen reaching 13,119 patients by 2026. By 2026, the longer all-oral regimen is projected to be used by 19,262 patients, and individualised treatment regimens by 15,344 patients.

CONCLUSION

The study shows BPaL/M will be used in majority of DR-TB patients by 2024, reaching 78% by 2026. However, national efforts to scale-up, case-finding, monitoring, drug-susceptibility testing, and implementation of new treatments will be essential for ensuring they are accessible to all eligible patients in the coming years and goals for ending TB are met. There is an urgent need to engage communities in capacity building and demand generation.

[Basic Knowledge of Hygiene in Voluntary Disaster Control Using - German Red Cross in the Rhein-Erft District as an Example]

Full-time workers in the rescue service are often exposed to a risk of infection. The volunteers of the German disaster control (Katastrophenschutz; KatS) are exposed to a similar risk of infection when they are deployed. The aim of this study was to investigate the hygiene status of the two operational units of the German Red Cross (Deutsches Rotes Kreuz; DRK) in the Rhein-Erft District (Rhein-Erft-Kreis; REK). The 66 volunteers of the two operational units (Einsatzeinheiten; EE) "NRW BM 05" and "NRW BM 02" were assessed by means of a written questionnaire. The results showed that they had good general knowledge of hygiene.There were, however, deficits in the knowledge of specific diseases and some multi-resistant pathogens. In general, perceived risk varied greatly, and was often above 5 on a scale from 1-10, where "1" stands for no perceived risk and "10" for high perceived risk. Thus, there is a certain "concern" about getting an infection in action. Appropriate training courses are needed to optimize this situation in the future.

War and Health Care Services Utilization for Chronic Diseases in Rural and Semiurban Areas of Tigray, Ethiopia

Importance

The war in Tigray, Ethiopia, has disrupted the health care system of the region. However, its association with health care services disruption for chronic diseases has not been well documented.

Objective

To assess the association of the war with the utilization of health care services for patients with chronic diseases.

Design, Setting, and Participants

Of 135 primary health care facilities, a registry-based cross-sectional study was conducted on 44 rural and semiurban facilities of Tigray. Data on health services utilization were extracted for patients with tuberculosis, HIV, diabetes, hypertension, and psychiatric disorders in the prewar period (September 1, to October 31, 2020) and during the first phase of the war period (November 4, 2020, to June 30, 2021).

Main Outcomes and Measures

Records on the number of follow-up, laboratory tests, and patients undergoing treatment of the aforementioned chronic diseases were counted during the prewar and war periods.

Results

Of 4645 records of patients with chronic diseases undergoing treatment during the prewar period, 998 records (21%) indicated having treatment during the war period. Compared with the prewar period, 59 of 180 individuals (33%; 95% CI, 26%-40%) had tuberculosis, 522 of 2211 (24%; 95% CI, 22%-26%) had HIV, 228 of 1195 (19%; 95% CI, 17%-21%) had hypertension, 123 of 632 (20%; 95% CI, 16%-22%) had psychiatric disorders, and 66 of 427 (15%; 95% CI, 12%-18%) had type 2 diabetes records, which revealed continued treatment during the war period. Of 174 records of patients with type 1 diabetes in the prewar period, at 2 to 3 months into the war, the numbers dropped to 10 with 94% decline compared with prewar observations.

Conclusions and Relevance

This study found that the war in Tigray has resulted in critical health care service disruption and high loss to follow-up for patients with chronic disease, likely leading to increased morbidity and mortality. Local, national, and global policymakers must understand the extent and impact of the service disruption and urge their efforts toward restoration of those services.

A systematic literature review of economic evaluation studies of interventions impacting antimicrobial resistance

BACKGROUND

Antimicrobial resistance (AMR) is accelerated by widespread and inappropriate use of antimicrobials. Many countries, including those in low- and middle- income contexts, have started implementing interventions to tackle AMR. However, for many interventions there is little or no economic evidence with respect to their cost-effectiveness. To help better understand the scale of this evidence gap, we conducted a systematic literature review to provide a comprehensive summary on the value for money of different interventions affecting AMR.

METHODS

A systematic literature review was conducted of economic evaluations on interventions addressing AMR. a narrative synthesis of findings was produced. Systematic searches for relevant studies were performed across relevant databases and grey literature sources such as unpublished studies, reports, and other relevant documents. All identified economic evaluation studies were included provided that they reported an economic outcome and stated that the analysed intervention aimed to affect AMR or antimicrobial use in the abstract. Studies that reported clinical endpoints alone were excluded. Selection for final inclusion and data extraction was performed by two independent reviewers. A quality assessment of the evidence used in the included studies was also conducted.

RESULTS

28,597 articles were screened and 35 articles were identified that satisfied the inclusion criteria. The review attempted to answer the following questions: (1) What interventions to address AMR have been the subject of an economic evaluation? (2) In what types of setting (e.g. high-income, low-income, regions etc.) have these economic evaluations been focused? (3) Which interventions have been estimated to be cost-effective, and has this result been replicated in other settings/contexts? (4) What economic evaluation methods or techniques have been used to evaluate these interventions? (5) What kind and quality of data has been used in conducting economic evaluations for these interventions?

DISCUSSION

The review is one of the first of its kind, and the most recent, to systematically review the literature on the cost-effectiveness of AMR interventions. This review addresses an important evidence gap in the economics of AMR and can assist AMR researchers' understanding of the state of the economic evaluation literature, and therefore inform future research. Systematic review registration PROSPERO (CRD42020190310).

Epidemiology and Drug Resistance Patterns of Mycobacterium tuberculosis in High-Burden Area in Western Siberia, Russia

Russia is a high-burden area for multidrug-resistant tuberculosis (MDR-TB). Here, we studied the epidemiological situation and drug resistance patterns of Mycobacterium tuberculosis in the Omsk region in Western Siberia. M. tuberculosis isolates (n = 851) were recovered from newly diagnosed TB patients in 2021. The isolates were tested by bacteriological and molecular methods, and long-term epidemiological data were analyzed. The TB incidence dec, this is not variablereased from 93.9 in 2012 to 48.1 in 2021, per 100,000 population, but the primary MDR-TB rate increased from 19.2% to 26.4%. The destructive forms of tuberculosis accounted for 37.8% of all cases, while 35.5% of patients were smear-positive. Of all isolates tested, 55.2% were culture-positive, of which 94.5% were further tested for phenotypic drug resistance and associated mutations. More than half (53.4%) of isolates were drug-resistant, 13.9% were monoresistant and 67.9% were MDR. Among MDR isolates, 40.4% were pre-XDR, and 19.2% were XDR. The spectrum of drug resistance included second-line drugs (new-generation fluoroquinolones, linezolid), which significantly increase the risk of an adverse outcome in patients. In conclusion, our results highlight the critical importance of monitoring drug resistance in circulating M. tuberculosis strains emerging due to ineffective treatment and active transmission.

Truenat MTB assays for pulmonary tuberculosis and rifampicin resistance in adults

This is a protocol for a Cochrane Review (diagnostic). The objectives are as follows:

To determine the diagnostic accuracy of Truenat assays (MTB, MTB Plus, and MTB RIF Dx) for detecting pulmonary tuberculosis and rifampicin resistance in adults with presumptive pulmonary tuberculosis.

Clinician perspectives of drug-resistant tuberculosis care services in the Philippines

BACKGROUND/OBJECTIVES

In the Philippines, treatment success rates for drug-resistant tuberculosis (DR-TB) remains low and little is known about the quality of DR-TB services. This study aimed to explore clinician's perspectives of DR-TB care services.

METHODS

We conducted semi-structured in-depth interviews from January-March 2018 with 11 providers selected purposively to explore the barriers associated with DR-TB care service delivery, best practices, and recommendations for enhancing patient care. Emerging themes were organized according to the socio-ecological framework.

RESULTS

Five major themes were identified: (1) nurses do not feel empowered; (2) particular patients are left behind and more vulnerable than others; (3) infection control practices, fear, and limited capacity in rural health centers; (4) financial insecurity due to program reimbursement mechanisms; and (5) local government support is limited and requires more involvement in support of DR-TB elimination activities. Best practices focused on tailored approaches that eliminated structural, economic, and motivational barriers for patients. Participants recommended financial support from local government units, nutritional assistance for patients, and refresher training for healthcare workers.

CONCLUSION

The findings provide additional understanding regarding the barriers that limit successful DR-TB care delivery and provide critical information to improve clinical practice and develop public health interventions for frontline staff including nurses in the Philippines. These strategies could ultimately reduce disparities associated with access to care and treatment adherence, if implemented.

Antibiotic resistance acquisition versus primary transmission in the presentation of extensively drug-resistant tuberculosis

Mycobacterium tuberculosis is the leading cause of mortality worldwide due to a single bacterial pathogen. Of concern is the negative impact that the COVID-19 pandemic has had on the control of tuberculosis (TB) including drug-resistant forms of the disease. Antimicrobial resistance increases the likelihood of worsened outcomes in TB patients including treatment failure and death. Multidrug-resistant (MDR) strains, resistant to first-line drugs isoniazid and rifampin, and extensively drug-resistant (XDR) strains with further resistance to second-line drugs (SLD), threaten control programs designed to lower TB incidence and end the disease as a public health challenge by 2030, in accordance with UN Sustainable Development Goals. Tackling TB requires an understanding of the pathways through which drug resistance emerges. Here, the roles of acquired resistance mutation, and primary transmission, are examined with regard to XDR-TB. It is apparent that XDR-TB can emerge from MDR-TB through a small number of additional resistance mutations that occur in patients undergoing drug treatment. Rapid detection of resistance, to first-line drugs and SLD, at the initiation of and during treatment, and prompt adjustment of regimens are required to ensure treatment success in these patients. Primary transmission is predicted to make an increasing contribution to the XDR-TB caseload in the future. Much work is required to improve the implementation of the World Health Organization-recommended infection control practices and block onward transmission of XDR-TB patients to contacts including health-care workers. Finally, limiting background resistance to fluoroquinolones in pre-XDR strains of M. tuberculosis will necessitate better antimicrobial stewardship in the broader use of this drug class.

Global trends, regional differences and age distribution for the incidence of HIV and tuberculosis co-infection from 1990 to 2019: results from the global burden of disease study 2019

BACKGROUND

People living with human immunodeficiency virus (HIV) are more likely to develop tuberculosis (TB), and their co-infection (HIV-TB) increases the risk of death. We aimed to describe the global trends, regional differences and age distribution of HIV-TB.

METHODS

Annual new cases, age-standardized incidence rates (ASRs) and age-specific incidence rates with 95% uncertainty intervals (UIs) of HIV-infected drug-susceptible tuberculosis (HIV-DS-TB), HIV-infected multidrug-resistant tuberculosis without extensive drug resistance (HIV-MDR-TB) and HIV-infected extensively drug-resistant tuberculosis (HIV-XDR-TB) during 1990-2019 were collected from the Global Burden of Disease Study 2019. To reveal the trends of HIV-TB by region and age, the percentage change of new cases and estimated annual percentage change (EAPC) of ASRs were calculated.

RESULTS

The ASR of HIV-XDR-TB increased significantly by an average of 14.77% (95% CI: 11.05%-18.62%) per year during 1990-2019 worldwide, while the ASRs of HIV-DS-TB and HIV-MDR-TB decreased after 2005. HIV-XDR-TB was a great threat to Eastern Europe for the largest number of new cases (792, 95% UI: 487-1167) and the highest ASR (0.34 per 100,000 population, 95% UI: 0.21-0.50). In addition, Oceania had the largest rise in ASRs of HIV-MDR-TB (EAPC = 22.56, 95% CI: 18.62-26.64) and HIV-XDR-TB (EAPC = 32.95, 95% CI: 27.90-38.20) during 1990-2019. Recently, age-specific incidence rates of HIV-XDR-TB increased in all age groups, especially in the 50-69 age groups among high, low-middle and low Socio-Demographic Index regions. Additionally, the proportion of patients aged <15 years was nearly 10% of new cases in sub-Saharan Africa in 2019, which was higher than in other regions.

CONCLUSIONS

HIV-infected drug-resistant TB is common in Oceania and Eastern Europe. Moreover, HIV-XDR-TB among elderly people became increasingly prevalent. In the future, the collaboration of management for HIV and TB should be intensified in Oceania and Eastern Europe, and more concerns need to be paid in elderly people.

Multidrug-Resistant Tuberculosis in U.S.-Bound Immigrants and Refugees

Rationale: Approximately two-thirds of new cases of tuberculosis (TB) in the United States are among non-U.S.-born persons. Culture-based overseas TB screening in U.S.-bound immigrants and refugees has substantially reduced the importation of TB into the United States, but it is unclear to what extent this program prevents the importation of multidrug-resistant TB (MDR-TB). Objectives: To study the epidemiology of MDR-TB in U.S.-bound immigrants and refugees and to evaluate the effect of culture-based overseas TB screening in U.S.-bound immigrants and refugees on reducing the importation of MDR-TB into the United States. Methods: We analyzed data of immigrants and refugees who completed overseas treatment for culture-positive TB during 2015-2019. We also compared mean annual number of MDR-TB cases in non-U.S.-born persons within 1 year of arrival in the United States between 1996-2006 (when overseas screening followed a smear-based algorithm) and 2014-2019 (after full implementation of a culture-based algorithm). Results: Of 3,300 culture-positive TB cases identified by culture-based overseas TB screening in immigrants and refugees during 2015-2019, 122 (3.7%; 95% confidence interval [CI], 3.1-4.1) had MDR-TB, 20 (0.6%; 95% CI, 0.3-0.9) had rifampicin-resistant TB, 382 (11.6%; 95% CI, 10.5-12.7) had isoniazid-resistant TB, and 2,776 (84.1%; 95% CI, 82.9-85.4) had rifampicin- and isoniazid-susceptible TB. None were diagnosed with extensively drug-resistant TB. All 3,300 persons with culture-positive TB completed treatment overseas; of 70 and 11 persons who were treated overseas for MDR-TB and rifampicin-resistant TB, respectively, none were diagnosed with TB disease at postarrival evaluation in the United States. Culture-based overseas TB screening in U.S.-bound immigrants and refugees prevented 24.4 MDR-TB cases per year from arriving in the United States, 18.2 cases more than smear-based overseas TB screening. The mean annual number of MDR-TB cases among non-U.S.-born persons within 1 year of arrival in the United States decreased from 34.6 cases in 1996-2006 to 19.5 cases in 2014-2019 (difference of 15.1; P < 0.001). Conclusions: Culture-based overseas TB screening in U.S.-bound immigrants and refugees substantially reduced the importation of MDR-TB into the United States.

Recently developed drugs for the treatment of drug-resistant tuberculosis: a research and development case study

Two drugs with novel mechanisms of action, the diarylquinoline bedaquiline and the nitroimidazole delamanid-as well as pretomanid from the same class of drugs as delamanid-have recently become available to treat drug-resistant tuberculosis (DR-TB) after many decades of little innovation in the field of DR-TB treatment. Despite evidence of improved efficacy and reduced toxicity of multidrug regimens including the two agents, access to bedaquiline and delamanid has been limited in many settings with a high burden of DR-TB and consistently poor treatment outcomes. Aside from regulatory, logistic and cost barriers at country level, uptake of the novel agents was complicated by gaps in knowledge for optimal use in clinical practice after initial market approval. The main incentives of the current pharmaceutical research and development paradigm are structured around obtaining regulatory approval, which in turn requires efficacy and safety data generated by clinical trials. Recently completed and ongoing clinical trials did not answer critical questions of how to provide shorter, less toxic treatment DR-TB treatment regimens containing bedaquiline and delamanid and improve patient outcomes. Voluntary generation of evidence that is not part of this process-yet essential from a clinical or policy perspective-has been left to non-sponsor partners and researchers, often without collaborative efforts to improve post-regulatory approval access to life-saving drugs. Additionally, these efforts are currently not recognised in the value chain of the research and development process, and there are no incentives to make this critical research happen in a coordinated way.

Changing Epidemiology of TB in Shandong, China Driven by Demographic Changes

Tuberculosis (TB) incidence has been in steady decline in China over the last few decades. However, ongoing demographic transition, fueled by aging, and massive internal migration could have important implications for TB control in the future. We collated data on TB notification, demography, and drug resistance between 2004 and 2017 across seven cities in Shandong, the second most populous province in China. Using these data, and age-period-cohort models, we (i) quantified heterogeneities in TB incidence across cities, by age, sex, resident status, and occupation and (ii) projected future trends in TB incidence, including drug-resistant TB (DR-TB). Between 2006 and 2017, we observed (i) substantial variability in the rates of annual change in TB incidence across cities, from -4.84 to 1.52%; (ii) heterogeneities in the increments in the proportion of patients over 60 among reported TB cases differs from 2 to 13%, and from 0 to 17% for women; (iii) huge differences across cities in the annual growths in TB notification rates among migrant population between 2007 and 2017, from 2.81 cases per 100K migrants per year in Jinan to 22.11 cases per 100K migrants per year in Liaocheng, with drastically increasing burden of TB cases from farmers; and (iv) moderate and stable increase in the notification rates of DR-TB in the province. All of these trends were projected to continue over the next decade, increasing heterogeneities in TB incidence across cities and between populations. To sustain declines in TB incidence and to prevent an increase in Multiple DR-TB (MDR-TB) in the future in China, future TB control strategies may (i) need to be tailored to local demography, (ii) prioritize key populations, such as elderly and internal migrants, and (iii) enhance DR-TB surveillance.

Potential contribution of HIV during first-line tuberculosis treatment to subsequent rifampicin-monoresistant tuberculosis and acquired tuberculosis drug resistance in South Africa: a retrospective molecular epidemiology study

Background

South Africa has a high burden of rifampicin-resistant tuberculosis (including multidrug-resistant [MDR] tuberculosis), with increasing rifampicin-monoresistant (RMR) tuberculosis over time. Resistance acquisition during first-line tuberculosis treatment could be a key contributor to this burden, and HIV might increase the risk of acquiring rifampicin resistance. We assessed whether HIV during previous treatment was associated with RMR tuberculosis and resistance acquisition among a retrospective cohort of patients with MDR or rifampicin-resistant tuberculosis.

Methods

In this retrospective cohort study, we included all patients routinely diagnosed with MDR or rifampicin-resistant tuberculosis in Khayelitsha, Cape Town, South Africa, between Jan 1, 2008, and Dec 31, 2017. Patient-level data were obtained from a prospective database, complemented by data on previous tuberculosis treatment and HIV from a provincial health data exchange. Stored MDR or rifampicin-resistant tuberculosis isolates from patients underwent whole-genome sequencing (WGS). WGS data were used to infer resistance acquisition versus transmission, by identifying genomically unique isolates (single nucleotide polymorphism threshold of five). Logistic regression analyses were used to assess factors associated with RMR tuberculosis and genomic uniqueness.

Findings

The cohort included 2041 patients diagnosed with MDR or rifampicin-resistant tuberculosis between Jan 1, 2008, and Dec 31, 2017; of those, 463 (22·7%) with RMR tuberculosis and 1354 (66·3%) with previous tuberculosis treatment. In previously treated patients, HIV positivity during previous tuberculosis treatment versus HIV negativity (adjusted odds ratio [OR] 2·07, 95% CI 1·35–3·18), and three or more previous tuberculosis treatment episodes versus one (1·96, 1·21–3·17) were associated with RMR tuberculosis. WGS data showing MDR or rifampicin-resistant tuberculosis were available for 1169 patients; 360 (30·8%) isolates were identified as unique. In previously treated patients, RMR tuberculosis versus MDR tuberculosis (adjusted OR 4·96, 3·40–7·23), HIV positivity during previous tuberculosis treatment (1·71, 1·03–2·84), and diagnosis in 2013–17 (1·42, 1·02–1·99) versus 2008–12, were associated with uniqueness. In previously treated patients with RMR tuberculosis, HIV positivity during previous treatment (adjusted OR 5·13, 1·61–16·32) was associated with uniqueness as was female sex (2·50 [1·18–5·26]).

Interpretation

These data suggest that HIV contributes to rifampicin-resistance acquisition during first-line tuberculosis treatment and that this might be driving increasing RMR tuberculosis over time. Large-scale prospective cohort studies are required to further quantify this risk.

Funding

Swiss National Science Foundation, South African National Research Foundation, and Wellcome Trust.

Community-Based Ototoxicity Monitoring for Drug-Resistant Tuberculosis in South Africa: An Evaluation Study

In response to the drug-resistant tuberculosis (DRTB) ototoxicity burden in South Africa, ototoxicity monitoring has been decentralised, with community health workers (CHWs) acting as facilitators. This study describes a community-based ototoxicity monitoring programme (OMP) for patients with DRTB. Findings are compared to the recommended guidelines for ototoxicity monitoring, the OMP protocol and published studies. This was a retrospective study of longitudinal ototoxicity monitoring of 831 patients with DRTB, using data collected at community-based clinics in the City of Cape Town between 2013 and 2017. Approximately half (46.8%) of the patients had an initial assessment conducted in accordance with the OMP protocol recommendations, and follow-up rates (79.5%) were higher than those of a similar DRTB programme. However, patients in this study were not monitored within the timeframes or with the regularity recommended by the guidelines or the OMP protocol. Extended high-frequency pure-tone audiometry (27.5%) was underutilised by testers and data recording was inconsistent (e.g., 37.7% of patient gender was not recorded by testers). Community-based OMP using CHWs to facilitate monitoring showed improvement over previous hospital-based reports, with more accessible services and higher follow-up rates. However, to improve OMP outcomes, OMP managers should reassess current protocols and data recording practices.

Evaluation of Berberine as an Adjunct to TB Treatment

Tuberculosis (TB) is the global health problem with the second highest number of deaths from a communicable disease after COVID-19. Although TB is curable, poor health infrastructure, long and grueling TB treatments have led to the spread of TB pandemic with alarmingly increasing multidrug-resistant (MDR)-TB prevalence. Alternative host modulating therapies can be employed to improve TB drug efficacies or dampen the exaggerated inflammatory responses to improve lung function. Here, we investigated the adjunct therapy of natural immune-modulatory compound berberine in C57BL/6 mouse model of pulmonary TB. Berberine treatment did not affect Mtb growth in axenic cultures; however, it showed increased bacterial killing in primary murine bone marrow-derived macrophages and human monocyte-derived macrophages. Ad libitum berberine administration was beneficial to the host in combination with rifampicin and isoniazid. Berberine adjunctive treatment resulted in decreased lung pathology with no additive or synergistic effects on bacterial burdens in mice. Lung immune cell flow cytometry analysis showed that adjunctive berberine treatment decreased neutrophil, CD11b+ dendritic cell and recruited interstitial macrophage numbers. Late onset of adjunctive berberine treatment resulted in a similar phenotype with consistently reduced numbers of neutrophils both in lungs and the spleen. Together, our results suggest that berberine can be supplemented as an immunomodulatory agent depending on the disease stage and inflammatory status of the host.

Mycobacterium tuberculosis strain lineage in mixed tribal population across India and Andaman Nicobar Island

In India, the tribal population constitutes almost 8.6% of the nation's total population. Despite their large presence, there are only a few reports available on Mycobacterium tuberculosis (M. tb) strain prevalence in Indian tribal communities considering the mobile nature of this population and also the influence of the mainstream populations they coexist within many areas for their livelihood. This study attempts to provide critical information pertaining to the TB strain diversity, its public health implications, and distribution among the tribal population in eleven Indian states and Andaman & Nicobar (A&N) Island. The study employed a population-based molecular approach. Clinical isolates were received from 66 villages (10 states and Island) and these villages were selected by implying situation analysis. A total of 78 M. tb clinical isolates were received from 10 different states and A&N Island. Among these, 16 different strains were observed by spoligotyping technique. The major M. tb strains spoligotype belong to the Beijing, CAS1_DELHI, and EAI5 family of M. tb strains followed by EAI1_SOM, EAI6_BGD1, LAM3, LAM6, LAM9, T1, T2, U strains. Drug-susceptibility testing (DST) results showed almost 15.4% of clinical isolates found to be resistant to isoniazid (INH) or rifampicin (RMP) + INH. Predominant multidrug-resistant (MDR-TB) isolates seem to be Beijing strain. Beijing, CAS1_DELHI, EAI3_IND, and EAI5 were the principal strains infecting mixed tribal populations across India. Despite the small sample size, this study has demonstrated higher diversity among the TB strains with significant MDR-TB findings. Prevalence of Beijing MDR-TB strains in Central, Southern, Eastern India and A&N Island indicates the transmission of the TB strains.

A protocol for a systematic literature review of economic evaluation studies of interventions to address antimicrobial resistance

BACKGROUND

Antimicrobial resistance (AMR) is accelerated by the widespread and often indiscriminate use of antimicrobials in humans, animals, and the environment. In 2015, the World Health Organization recognised AMR as one of the top ten global health threats, due to its potential to neutralise humanity's advancements in western medicine by enabling the emergence of new strains of existing pathogens, many of which have no available treatments. Over the past decade, several countries, including those in low- and middle-income contexts, have started implementing interventions to tackle AMR. However, economic evidence regarding the cost-effectiveness of these interventions remains weak. To address this evidence gap, we will conduct a systematic literature review to provide a comprehensive summary on the value for money of different AMR interventions.

METHODS

We aim to conduct a systematic literature review of all available economic evaluations on interventions addressing AMR and will provide a narrative synthesis of our findings. Systematic searches for relevant studies will be performed across all suitable databases as well as in grey literature sources such as unpublished studies, reports, and other relevant documents. All economic evaluation studies will be included as long as they report an economic outcome and have stated that the analysed intervention will reduce antimicrobial resistance or antimicrobial use in the abstract. Those studies reporting clinical endpoints alone will be excluded. Selection for final inclusion and data extraction will be performed by two independent reviewers.

DISCUSSION

The review will be one of the first of its kind, and the most recent, to systematically review literature on the cost-effectiveness of AMR interventions, an important evidence gap in the economics of AMR. The findings will enable policy and decision-makers, particularly in resource-constrained settings, to better use available resources when selecting interventions to address AMR burdens, SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42020190310.

All-oral longer regimens are effective for the management of multidrug resistant tuberculosis in high burden settings

BACKGROUND

Recent World Health Organisation guidance on drug-resistant tuberculosis treatment de-prioritised injectable agents, in use for decades, and endorsed all-oral longer regimens. However, questions remain about the role of the injectable agent, particularly in the context of regimens using new and repurposed drugs. We compared the effectiveness of an injectable-containing regimen to that of an all-oral regimen among patients with drug-resistant tuberculosis who received bedaquiline- and/or delamanid as part of their multidrug regimen.

METHODS

Patients with a positive baseline culture were included. Six-month culture conversion was defined as two consecutive negative cultures collected >15 days apart. We derived predicted probabilities of culture conversion and relative risk using marginal standardisation methods.

RESULTS

Culture conversion was observed in 83.8% (526/628) of patients receiving an all-oral regimen and 85.5% (425/497) of those receiving an injectable-containing regimen. The adjusted relative risk comparing injectable-containing regimens to all-oral regimens was 0.96 (95%CI: 0.88-1.04). We found very weak evidence of effect modification by HIV status: among patients living with HIV, there was a small increase in the frequency of conversion among those receiving an injectable-containing regimen, relative to an all-oral regimen, which was not apparent in HIV-negative patients.

CONCLUSIONS

Among individuals receiving bedaquiline and/or delamanid as part of a multidrug regimen for drug-resistant tuberculosis, there was no significant difference between those who received an injectable and those who did not regarding culture conversion within 6 months. The potential contribution of injectable agents in the treatment of drug-resistant tuberculosis among those who were HIV positive requires further study.

Artificial intelligence in overcoming rifampicin resistant-screening challenges in Indonesia: a qualitative study on the user experience of CUHAS-ROBUST

Purpose

The Chulalongkorn-Hasanuddin Rifampicin-Resistant Tuberculosis Screening Tool (CUHAS-ROBUST) is an artificial intelligence–based (AI–based) application for rifampicin-resistant tuberculosis (RR-TB) screening. This study aims to elaborate on the drug-resistant TB (DR-TB) problem and the impact of CUHAS-ROBUST implementation on RR-TB screening.

Design/methodology/approach

A qualitative approach with content analysis was performed from September 2020 to October 2020. Medical staff from the primary care center were invited online for application trials and in-depth video call interviews. Transcripts were derived as a data source. An inductive thematic data saturation technique was conducted. Descriptive data of participants, user experience and the impact on the health service were summarized

Findings

A total of 33 participants were selected from eight major islands in Indonesia. The findings show that DR-TB is a new threat, and its diagnosis faces obstacles particularly prolonged waiting time and inevitable delayed treatment. Despite overcoming the RR-TB screening problems with fast prediction, the dubious screening performance, and the reliability of data collection for input parameters were the main concerns of CUHAS-ROBUST. Nevertheless, this application increases the confidence in decision-making, promotes medical procedure compliance, active surveillance and enhancing a low-cost screening approach.

Originality/value

The CUHAS-ROBUST achieved its purpose as a tool for clinical decision-making in RR-TB screening. Moreover, this study demonstrates AI roles in enhancing health-care quality and boost public health efforts against tuberculosis.

Experience with UV-C Air Disinfection in Some Russian Hospitals†

Although the environmental control measure of ultraviolet germicidal irradiation (UVGI) for disinfection has not been widely used in the United States and some parts of the world in the past few decades, this technology has been well applied in Russia. UVGI technology has been particularly useful with regard to limiting TB transmission in medical facilities. There is good evidence that UV‐C (180−280 nm) air disinfection can be a helpful intervention in reducing transmission of the SARS‐CoV‐2 virus.

Trends & treatment outcomes of multidrug-resistant tuberculosis in Delhi, India (2009-2014): A retrospective record-based study

Background & objectives:

The increase in the burden of multidrug-resistant tuberculosis (MDR-TB) is a matter of grave concern. The present study was undertaken to describe MDR-TB treatment outcome trends in Delhi and their epidemiological correlates, to assess the adequacy of treatment records and to also generate evidence towards influencing and improving practices related to the MDR-TB control programme.

Methods:

A retrospective record-based study (2009-2014) was conducted in three major drug resistance TB treatment centres of Delhi. Treatment outcomes and adverse effects were extracted from the existing programme records including patients’ treatment cards and laboratory registers.

Results:

A total of 2958 MDR-TB patients were identified from the treatment cards, of whom 1749 (59.12%) were males. The mean (±standard deviation) age was 30.56±13.5 years. Favourable treatment outcomes were reported in 1371 (53.28%) patients, but they showed a declining trend during the period of observation. On binomial logistic regression analysis, patients with age ≥35 yr, male sex and undernourishment (body mass index <18.5) at the time of treatment initiation had a significantly increased likelihood of unfavourable MDR-TB treatment outcome (P<0.001).

Interpretation & conclusions:

The study showed an increasing burden of MDR-TB patients, especially in the young population with increased risk of transmission posing a major challenge in achieving TB elimination targets.

The epidemiologic impact and cost-effectiveness of new tuberculosis vaccines on multidrug-resistant tuberculosis in India and China

BACKGROUND

Despite recent advances through the development pipeline, how novel tuberculosis (TB) vaccines might affect rifampicin-resistant and multidrug-resistant tuberculosis (RR/MDR-TB) is unknown. We investigated the epidemiologic impact, cost-effectiveness, and budget impact of hypothetical novel prophylactic prevention of disease TB vaccines on RR/MDR-TB in China and India.

METHODS

We constructed a deterministic, compartmental, age-, drug-resistance- and treatment history-stratified dynamic transmission model of tuberculosis. We introduced novel vaccines from 2027, with post- (PSI) or both pre- and post-infection (P&PI) efficacy, conferring 10 years of protection, with 50% efficacy. We measured vaccine cost-effectiveness over 2027-2050 as USD/DALY averted-against 1-times GDP/capita, and two healthcare opportunity cost-based (HCOC), thresholds. We carried out scenario analyses.

RESULTS

By 2050, the P&PI vaccine reduced RR/MDR-TB incidence rate by 71% (UI: 69-72) and 72% (UI: 70-74), and the PSI vaccine by 31% (UI: 30-32) and 44% (UI: 42-47) in China and India, respectively. In India, we found both USD 10 P&PI and PSI vaccines cost-effective at the 1-times GDP and upper HCOC thresholds and P&PI vaccines cost-effective at the lower HCOC threshold. In China, both vaccines were cost-effective at the 1-times GDP threshold. P&PI vaccine remained cost-effective at the lower HCOC threshold with 49% probability and PSI vaccines at the upper HCOC threshold with 21% probability. The P&PI vaccine was predicted to avert 0.9 million (UI: 0.8-1.1) and 1.1 million (UI: 0.9-1.4) second-line therapy regimens in China and India between 2027 and 2050, respectively.

CONCLUSIONS

Novel TB vaccination is likely to substantially reduce the future burden of RR/MDR-TB, while averting the need for second-line therapy. Vaccination may be cost-effective depending on vaccine characteristics and setting.

Capture and visualization of live Mycobacterium tuberculosis bacilli from tuberculosis patient bioaerosols

Interrupting transmission is an attractive anti-tuberculosis (TB) strategy but it remains underexplored owing to our poor understanding of the events surrounding transfer of Mycobacterium tuberculosis (Mtb) between hosts. Determining when live, infectious Mtb bacilli are released and by whom has proven especially challenging. Consequently, transmission chains are inferred only retrospectively, when new cases are diagnosed. This process, which relies on molecular analyses of Mtb isolates for epidemiological fingerprinting, is confounded by the prolonged infectious period of TB and the potential for transmission from transient exposures. We developed a Respiratory Aerosol Sampling Chamber (RASC) equipped with high-efficiency filtration and sampling technologies for liquid-capture of all particulate matter (including Mtb) released during respiration and non-induced cough. Combining the mycobacterial cell wall probe, DMN-trehalose, with fluorescence microscopy of RASC-captured bioaerosols, we detected and quantified putative live Mtb bacilli in bioaerosol samples arrayed in nanowell devices. The RASC enabled non-invasive capture and isolation of viable Mtb from bioaerosol within 24 hours of collection. A median 14 live Mtb bacilli (range 0-36) were isolated in single-cell format from 90% of confirmed TB patients following 60 minutes bioaerosol sampling. This represented a significant increase over previous estimates of transmission potential, implying that many more organisms might be released daily than commonly assumed. Moreover, variations in DMN-trehalose incorporation profiles suggested metabolic heterogeneity in aerosolized Mtb. Finally, preliminary analyses indicated the capacity for serial image capture and analysis of nanowell-arrayed bacilli for periods extending into weeks. These observations support the application of this technology to longstanding questions in TB transmission including the propensity for asymptomatic transmission, the impact of TB treatment on Mtb bioaerosol release, and the physiological state of aerosolized bacilli.

Addressing the drug-resistant tuberculosis challenge through implementing a mixed model of care in Uganda

Worldwide, Drug-resistant Tuberculosis (DR-TB) remains a big problem; the diagnostic capacity has superseded the clinical management capacity thereby causing ethical challenges. In Sub-Saharan Africa, treatment is either inadequate or lacking and some diagnosed patients are on treatment waiting lists. In Uganda, various health system challenges impeded scale-up of DR-TB care in 2012; only three treatment initiation facilities existed, with only 41 of the estimated 1010 RR-TB/MDR-TB cases enrolled on treatment yet 300 were on the waiting list and there was no DR-TB treatment scale-up plan. To scale up care, the National TB and leprosy Program (NTLP) with partners rolled out a DR-TB mixed model of care. In this paper, we share achievements and outcomes resulting from the implementation of this mixed Model of DR-TB care. Routine NTLP DR-TB program data on treatment initiation site, number of patients enrolled, their demographic characteristics, patient category, disease classification (based on disease site and human immunodeficiency virus (HIV) status), on co-trimoxazole preventive therapy (CPT) and antiretroviral therapy (ART) statuses, culture results, smear results and treatment outcomes (6, 12, and 24 months) from 2012 to 2017 RR-TB/MDR-TB cohorts were collected from all the 15 DR-TB treatment initiation sites and descriptive analysis was done using STATA version 14.2. We presented outcomes as the number of patient backlog cleared, DR-TB initiation sites, RR-TB/DR-TB cumulative patients enrolled, percentage of co-infected patients on the six, twelve interim and 24 months treatment outcomes as per the Uganda NTLP 2016 Programmatic Management of drug-resistant Tuberculosis (PMDT) guidelines (NTLP, 2016). Over the period 2013–2015, the RR-TB/MDR-TB Treatment success rate (TSR) was sustained between 70.1% and 74.1%, a performance that is well above the global TSR average rate of 50%. Additionally, the cure rate increased from 48.8% to 66.8% (P = 0.03). The Uganda DR-TB mixed model of care coupled with early application of continuous improvement approaches, enhanced cohort reviews and use of multi-disciplinary teams allowed for rapid DR-TB program expansion, rapid clearance of patient backlog, attainment of high cumulative enrollment and high treatment success rates. Sustainability of these achievements is needed to further reduce the DR-TB burden in the country. We highly recommend this mixed model of care in settings with similar challenges.

Tuberculosis diagnostics: overcoming ancient challenges with modern solutions

Rapid, sensitive, accurate and portable diagnostics are a mainstay of modern medicine. Tuberculosis is a disease that has been with us since time immemorial and, despite the fact that it can be treated and cured, it still remains the world's biggest infectious killer, taking the lives of millions annually. There have been important developments in the diagnostic devices for tuberculosis however, these are often prone to error, expensive, lack the necessary sensitivity or accuracy and, crucially, not sufficiently portable and thus not applicable in the remote, rural areas, where they are most needed. Modern solutions have been emerging in the past decade, seeking to overcome many of the inhibiting issues in this field by utilising recent advances in molecular biology, genetics and sequencing or even completely ‘reinventing the wheel’, by developing novel and unprecedented diagnostic techniques. In this mini review, the issues and challenges arising from the historical methods of diagnosing tuberculosis are discussed, followed by outlaying their particular lack of appropriateness for regions of the world where tuberculosis still remains endemic. Subsequently, more recent developments of new methods and technological advancements as ‘modern weapons’ in the battle to defeat this disease and associated challenges are reviewed, and finally an outlook is presented, highlighting the future of the modern solutions under development, which are envisioned to lay the platform for improvements in delivering timely intervention, reduce immense expense and burden on healthcare systems worldwide, while saving millions of lives and eventually, may enable the eradication of this ancient disease.

Prevalence, Clinical Presentation, and Outcome of Tuberculosis in Patients with Chronic Kidney Disease at a Tertiary Care Hospital in Nepal

Background

Tuberculosis (TB) is a serious public health threat in low- and middle-income countries like Nepal. Chronic kidney disease (CKD) patients are at higher risk of developing new infection as well as reactivation of TB. We aimed to determine the prevalence, clinical presentations, and outcome of TB in patients with CKD in Nepal.

Methods

A hospital-based cross-sectional study was performed at Tribhuvan University Teaching Hospital (TUTH), a tertiary level referral centre in Kathmandu, Nepal. We included patients older than 16 years with the diagnosis of CKD stage 3, 4, 5, and 5D (CKD 5 on maintenance dialysis); renal transplant recipients and patients living with HIV/AIDS were excluded. Tuberculosis was diagnosed based on clinical, radiological, and laboratory findings. Prior written informed consent was obtained. Approval was obtained from the Institutional Review Board of the Institute of Medicine. Data entry and statistical analysis were performed using SPSS v21.

Results

A total of 401 patients with CKD were included in the study (mean age, 50.92 ± 17.98 years; 64.8% male). The prevalence of TB in CKD patients was found to be 13.7% (55), out of which 49 were newly diagnosed cases. The most common clinical presentations of TB in CKD were anorexia (85.7%), fever (83.7%), weight loss (51%), and cough (49%). Thirty-eight patients (69.1%) had extrapulmonary TB (EPTB), 12 (21.8%) had pulmonary TB, 3 (5.5%) had disseminated TB, and 2 (3.6%) had miliary TB. Only 4.1% of cases were sputum smear positive. Pleural effusion (34.2%) was the most common EPTB. At 2 months of starting antitubercular therapy, 29 patients out of the 49 newly diagnosed cases of TB (59.2%) had responded to therapy. Mortality at 2 months was 28.6% (14 died amongst 49 patients). Four out of 49 patients (8.2%) did not improve, and 2 (4%) patients were lost to follow-up.

Conclusion

Prevalence and mortality of TB were higher in patients with CKD. Special attention must be given to these people for timely diagnosis and treatment as the presentation is different and diagnosis can be missed.

Prevalence of Antibiotic-Resistant Pulmonary Tuberculosis in Bangladesh: A Systematic Review and Meta-Analysis

Resistance to anti-tuberculosis (anti-TB) antibiotics is a major public health concern for many high-TB burden countries in Asia, including Bangladesh. Therefore, to represent the overall drug-resistance pattern against TB in Bangladesh, a systematic review and meta-analysis was conducted. Databases such as PubMed, Scopus, and Google Scholar were searched to identify studies related to antibiotic-resistant TB. A total of 24 studies covering 13,336 patients with TB were secured and included. The random-effects model was used to calculate the summary estimates. The pooled prevalence of any, mono, multi, poly, and extensive anti-TB antibiotic-resistances were 45.3% [95% CI: 33.5–57.1], 14.3% [95% CI: 11.4–17.2], 22.2% [95% CI: 18.8–25.7], 7.7% [95% CI: 5.6–9.7], and 0.3% [95% CI: 0.0–1.0], respectively. Among any first and second-line anti-TB drugs, isoniazid (35.0%) and cycloserine (44.6%) resistances were the highest, followed by ethambutol (16.2%) and gatifloxacin (0.2%). Any, multi, and poly drug-resistances were higher in retreatment cases compared to the newly diagnosed cases, although mono drug-resistance tended to be higher in newly diagnosed cases (15.7%) than that in retreatment cases (12.5%). The majority (82.6%) of the included studies were of high quality, with most not exhibiting publication bias. Sensitivity analyses confirmed that all outcomes are robust and reliable. It is concluded that resistance to anti-TB drugs in Bangladesh is rampant and fast growing. Therefore, the implementation of a nationwide surveillance system to detect suspected and drug-resistant TB cases, as well as to ensure a more encompassing treatment management by national TB control program, is highly recommended.

Minimum Inhibitory Concentrations of Fluoroquinolones and Pyrazinamide Susceptibility Correlate to Clinical Improvement in Multidrug-resistant Tuberculosis Patients: A Nationwide Swedish Cohort Study Over 2 Decades

BACKGROUND

Minimum inhibitory concentration (MIC) testing, unlike routine drug susceptibility testing (DST) at a single critical concentration, quantifies drug resistance. The association of MICs and treatment outcome in multidrug-resistant (MDR)-tuberculosis patients is unclear. Therefore, we correlated MICs of first- and second-line tuberculosis drugs with time to sputum culture conversion (tSCC) and treatment outcome in MDR-tuberculosis patients.

METHODS

Clinical and demographic data of MDR-tuberculosis patients in Sweden, including DST results, were retrieved from medical records from 1992 to 2014. MIC determinations were performed retrospectively for the stored individual Mycobacterium tuberculosis (Mtb) isolates using broth microdilution in Middlebrook 7H9. We fitted Cox proportional hazard models correlating MICs, DST results, and clinical variables to tSCC and treatment outcome.

RESULTS

Successful treatment outcome was observed in 83.5% (132/158) of MDR-tuberculosis patients. Increasing MICs of fluoroquinolones, diabetes, and age >40 years were significantly associated with unsuccessful treatment outcome. Patients treated with pyrazinamide (PZA) had a significantly shorter tSCC compared to patients who were not (median difference, 27 days).

CONCLUSIONS

Increasing MICs of fluoroquinolones were correlated with unsuccessful treatment outcome in MDR-tuberculosis patients. Further studies, including MIC testing and clinical outcome data to define clinical Mtb breakpoints, are warranted. PZA treatment was associated with shorter tSCC, highlighting the importance of PZA DST.

Building the Framework for Standardized Clinical Laboratory Reporting of Next-generation Sequencing Data for Resistance-associated Mutations in Mycobacterium tuberculosis Complex

Tuberculosis is the primary infectious disease killer worldwide, with a growing threat from multidrug-resistant cases. Unfortunately, classic growth-based phenotypic drug susceptibility testing (DST) remains difficult, costly, and time consuming, while current rapid molecular testing options are limited by the diversity of antimicrobial-resistant genotypes that can be detected at once. Next-generation sequencing (NGS) offers the opportunity for rapid, comprehensive DST without the time or cost burden of phenotypic tests and can provide useful information for global surveillance. As access to NGS expands, it will be important to ensure that results are communicated clearly, consistent, comparable between laboratories, and associated with clear guidance on clinical interpretation of results. In this viewpoint article, we summarize 2 expert workshops regarding a standardized report format, focusing on relevant variables, terminology, and required minimal elements for clinical and laboratory reports with a proposed standardized template for clinical reporting NGS results for Mycobacterium tuberculosis.

Linezolid resistance in patients with drug-resistant TB and treatment failure in South Africa

Objectives

Limited data exist on clinical associations and genotypic correlates of linezolid resistance in Mycobacterium tuberculosis. We aimed to describe mutations and clinical factors associated with phenotypic linezolid resistance from patients with drug-resistant TB at two public sector facilities in South Africa.

Methods

Adults and adolescents with treatment failure (culture positivity ≥4 months) on a linezolid-containing regimen were retrospectively identified. Phenotypic resistance, as defined by a linezolid MIC >1 mg/L, was assessed for retrieved isolates using broth microdilution. Targeted sequencing of rrl and rplC was performed, irrespective of growth on subculture.

Results

Thirty-nine patients with linezolid-based treatment failure were identified, 13 (33%) of whom had phenotypic or genotypic linezolid resistance after a median duration of 22 months (range = 7–32) of linezolid therapy. Paired MIC testing and genotyping was performed on 55 unique isolates. All isolates with phenotypic resistance (n = 16) were associated with known resistance mutations, most frequently due to the T460C substitution in rplC (n = 10); rrl mutations included G2814T, G2270C/T and A2810C. No mutations were detected in isolates with MICs at or below the critical concentration.

Conclusions

Linezolid resistance occurred in a third of patients with drug-resistant TB and treatment failure. Resistance occurred late and was predicted by a limited number of mutations in rrl and rplC. Screening for genotypic resistance should be considered for patients with a positive culture after 4 months of linezolid therapy in order to optimize treatment and avoid the toxicity of ineffective linezolid therapy.

Potential Impact of the Multi-Target Drug Approach in the Treatment of Some Complex Diseases

It is essential to acknowledge the efforts made thus far to manage or eliminate various disease burden faced by humankind. However, the rising global trends of the so-called incurable diseases continue to put pressure on Pharma industries and other drug discovery platforms. In the past, drugs with more than one target were deemed as undesirable options with interest being on the one-drug-single target. Despite the successes of the single-target drugs, it is currently beyond doubt that these drugs have limited efficacy against complex diseases in which the pathogenesis is dependent on a set of biochemical events and several bioreceptors operating concomitantly. Different approaches have thus been proposed to come up with effective drugs to combat even the complex diseases. In the past, the focus was on producing drugs from screening plant compounds; today, we talk about combination therapy and multi-targeting drugs. The multi-target drugs have recently attracted much attention as promising tools to fight against most challenging diseases, and thus a new research focus area. This review will discuss the potential impact of multi-target drug approach on various complex diseases with focus on malaria, tuberculosis (TB), diabetes and neurodegenerative diseases as the main representatives of multifactorial diseases. We will also discuss alternative ideas to solve the current problems bearing in mind the fourth industrial revolution on drug discovery.

A machine learning-based framework for Predicting Treatment Failure in tuberculosis: A case study of six countries

Tuberculosis is ranked as the 2nd deadliest disease in the world and is responsible for ten million deaths in 2017. Treatment failure is one of a main reason behind these deaths. Reasons of treatment failure are still unknown and the death rate due to TB is increasing. Machine learning and data analytics approaches are proved to be useful in healthcare domain in finding the associations among different attributes that can affect the outcome of any disease. Timely identification of reasons can save a patient's life. This study aims to find features that are strongly correlated with treatment failure using feature selection techniques. The validation of features is demonstrated using different classification algorithms. Moreover, this study provides a demographic based feature association of six highly burdened treatment failure countries. A verified real-life patient's dataset gathered from different countries including Azerbaijan, Belarus, Georgia, India, Moldova, and Romania is utilized to address the problem. Two types of experimentation are performed on combined dataset by achieving an average accuracy of 78% and an accuracy of 92% on Romania's data. Results shows the importance of features obtained through this study are highly influential in leading a patient towards treatment failure.

Rising challenge of multidrug-resistant tuberculosis in China: a predictive study using Markov modeling

BACKGROUND

Multidrug-resistant tuberculosis (MDR-TB) is on the rise in China. This study used a dynamic Markov model to predict the longitudinal trends of MDR-TB in China by 2050 and to assess the effects of alternative control measures.

METHODS

Eight states of tuberculosis transmission were set up in the Markov model using a hypothetical cohort of 100 000 people. The prevalence of MDR-TB and bacteriologically confirmed drug-susceptible tuberculosis (DS-TB+) were simulated and MDR-TB was stratified into whether the disease was treated with the recommended regimen or not.

RESULTS

Without any intervention changes to current conditions, the prevalence of DS-TB+ was projected to decline 67.7% by 2050, decreasing to 20 per 100 000 people, whereas that of MDR-TB was expected to triple to 58/100 000. Furthermore, 86.2% of the MDR-TB cases would be left untreated by the year of 2050. In the case where MDR-TB detection rate reaches 50% or 70% at 5% per year, the decline in prevalence of MDR-TB would be 25.9 and 36.2% respectively. In the case where treatment coverage was improved to 70% or 100% at 5% per year, MDR-TB prevalence in 2050 would decrease by 13.8 and 24.1%, respectively. If both detection rate and treatment coverage reach 70%, the prevalence of MDR-TB by 2050 would be reduced to 28/100 000 by a 51.7% reduction.

CONCLUSIONS

MDR-TB, especially untreated MDR-TB, would rise rapidly under China's current MDR-TB control strategies. Interventions designed to promote effective detection and treatment of MDR-TB are imperative in the fights against MDR-TB epidemics.

Guidance for Studies Evaluating the Accuracy of Rapid Tuberculosis Drug-Susceptibility Tests

The development and implementation of rapid molecular diagnostics for tuberculosis (TB) drug-susceptibility testing is critical to inform treatment of patients and to prevent the emergence and spread of resistance. Optimal trial planning for existing tests and those in development will be critical to rapidly gather the evidence necessary to inform World Health Organization review and to support potential policy recommendations. The evidence necessary includes an assessment of the performance for TB and resistance detection as well as an assessment of the operational characteristics of these platforms. The performance assessment should include analytical studies to confirm the limit of detection and assay ability to detect mutations conferring resistance across globally representative strains. The analytical evaluation is typically followed by multisite clinical evaluation studies to confirm diagnostic performance in sites and populations of intended use. This paper summarizes the considerations for the design of these analytical and clinical studies.

Outcome Impacts Due to Pathogen-Specific Antimicrobial Resistance: A Narrative Review of Published Literature

Antimicrobial resistance (AMR) has become a global threat to not only public health impacts but also clinical and economic outcomes. During the past decades, there have been many studies focusing on surveillance, mechanisms, and diagnostics of AMR in infectious diseases but the impacts on public health, clinical and economic outcomes due to emergence of these AMRs are rarely studied and reported. This review was aimed to summarize the findings from published studies to report the outcome impacts due to AMR of malaria, tuberculosis and HIV and briefly discuss the implications for application to other infectious diseases. PubMed/Medline and Google Scholar databases were used for search of empirical and peer-reviewed papers reporting public health, clinical and economic outcomes due to AMR of malaria, tuberculosis and HIV. Papers published through 1 December 2019 were included in this review. A total of 76 studies were included for this review, including 16, 49 and 11 on public health, clinical and economic outcomes, respectively. The synthesized data indicated that the emergence and spread of AMR of malaria, tuberculosis and HIV have resulted in adverse public health, clinical and economic outcomes. AMR of malaria, tuberculosis and HIV results in significant adverse impacts on public health, clinical and economic outcomes. Evidence from this review suggests the needs to consider the similar studies for other infectious diseases.

A model-based investigation into urban-rural disparities in tuberculosis treatment outcomes under the Revised National Tuberculosis Control Programme in India

In this study, we investigate differences in tuberculosis (TB) treatment outcomes between urban and rural India and estimate their impact on epidemiological outcomes such as TB incidence, prevalence and mortality using a mathematical model of TB transmission dynamics. Publicly available district-level treatment outcomes data for new and previously treated TB cases was analyzed in conjunction with census data providing the proportion of urban population in each district to determine the effect of urbanity/rurality on treatment outcomes. Districts were grouped in clusters based on the proportion of urban population in each district, wherein the clusters were identified by applying machine learning methods. Regression analyses revealed that average treatment success rates among both new and previously treated cases decline with increase in the proportion of urban population in a district cluster, with substantially sharper declines in treatment success rates with degree of urbanity observed for previously treated cases. The impact of differences in treatment outcomes on epidemiological outcomes was estimated using a dynamic transmission model developed for this purpose. For example, the cluster with highest treatment success rates is projected to have an average of 3.2% fewer deaths per 100,000 population in comparison with the national average across 2019–24, and the cluster with the lowest treatment success rates has an average of 4.5% more deaths per 100,000 in comparison with the national average. We anticipate that these disparities in TB treatment outcomes and epidemiology between urban and rural India may motivate investigations into the associated causes and their redressal.

Epidemiological cut-offs for Sensititre susceptibility testing of Mycobacterium tuberculosis: interpretive criteria cross validated with whole genome sequencing

Universal drug susceptibility testing (DST) is an important requirement of the End TB Strategy. The Sensititre broth micro-dilution assay (BMD) tests multiple drugs quantitatively. We defined interpretive criteria for this assay and analysed genotypic-phenotypic relationships. 385 Mycobacterium tuberculosis clinical isolates were processed for BMD and whole genome sequencing. The epidemiological cut-off value 99% (ECV99) amongst genotypically wild type (gWT) strains defined susceptibility. Minimum inhibitory concentration distributions of the resistance-associated variants (RAVs) for each drug were analysed. Susceptibility (µg/mL) criteria were determined as follows: rifampicin (≤0.125), isoniazid (≤0.25), ethambutol (≤2.0), moxifloxacin (≤0.5), levofloxacin (≤1.0), amikacin (≤2.0), kanamycin (≤8.0), capreomycin (≤4.0), clofazimine (≤0.25) and linezolid (≤2.0). Most drugs showed clear separation between gWT and RAV. Isoniazid showed a tri-modal pattern with 14/17 strains at ECV99 harbouring a fabG1 c. -15C > T RAV. Ethambutol RAVs at embB codons 306, 405 and 497 were responsible for resistance and showed differential distributions. Moxifloxacin RAVs (gyrA codon 90) were a dilution or two higher than the ECV99 while gyrB RAVs were uncommon and showed drug specific resistance propensity. Interpretive criteria established were robust facilitating progress towards universal DST and individualised precision medicine. This study demonstrates the value of quantitative DST to accurately interpret mutation data.

Thompson loop: opportunities for antitubercular drug design by targeting the weak spot in demethylmenaquinone methyltransferase protein

Graphical superimposed snapshots of the Thompson novel loop (yellow) of menG protein: apo (A) and bound (B) systems. The loop switches between open and closed conformations; critical for therapeutic activity.

Estimating treatment importance in multidrug-resistant tuberculosis using Targeted Learning: An observational individual patient data network meta-analysis

Persons with multidrug-resistant tuberculosis (MDR-TB) have a disease resulting from a strain of tuberculosis (TB) that does not respond to at least isoniazid and rifampicin, the two most effective anti-TB drugs. MDR-TB is always treated with multiple antimicrobial agents. Our data consist of individual patient data from 31 international observational studies with varying prescription practices, access to medications, and distributions of antibiotic resistance. In this study, we develop identifiability criteria for the estimation of a global treatment importance metric in the context where not all medications are observed in all studies. With stronger causal assumptions, this treatment importance metric can be interpreted as the effect of adding a medication to the existing treatments. We then use this metric to rank 15 observed antimicrobial agents in terms of their estimated add-on value. Using the concept of transportability, we propose an implementation of targeted maximum likelihood estimation, a doubly robust and locally efficient plug-in estimator, to estimate the treatment importance metric. A clustered sandwich estimator is adopted to compute variance estimates and produce confidence intervals. Simulation studies are conducted to assess the performance of our estimator, verify the double robustness property, and assess the appropriateness of the variance estimation approach.

Re-Understanding the Mechanisms of Action of the Anti-Mycobacterial Drug Bedaquiline

Bedaquiline (BDQ) inhibits ATP generation in Mycobacterium tuberculosis by interfering with the F-ATP synthase activity. Two mechanisms of action of BDQ are broadly accepted. A direct mechanism involves BDQ binding to the enzyme’s c-ring to block its rotation, thus inhibiting ATP synthesis in the enzyme’s catalytic α₃β₃-headpiece. An indirect mechanism involves BDQ uncoupling electron transport in the electron transport chain from ATP synthesis at the F-ATP synthase. In a recently uncovered second direct mechanism, BDQ binds to the enzyme’s ε-subunit to disrupt its ability to link c-ring rotation to ATP synthesis at the α₃β₃-headpiece. However, this mechanism is controversial as the drug’s binding affinity for the isolated ε-subunit protein is moderate and spontaneous resistance mutants in the ε-subunit cannot be isolated. Recently, the new, structurally distinct BDQ analogue TBAJ-876 was utilized as a chemical probe to revisit BDQ’s mechanisms of action. In this review, we first summarize discoveries on BDQ’s mechanisms of action and then describe the new insights derived from the studies of TBAJ-876. The TBAJ-876 investigations confirm the c-ring as a target, while also supporting a functional role for targeting the ε-subunit. Surprisingly, the new findings suggest that the uncoupler mechanism does not play a key role in BDQ’s anti-mycobacterial activity.

Projecting the impact of variable MDR-TB transmission efficiency on long-term epidemic trends in South Africa and Vietnam

Whether multidrug-resistant tuberculosis (MDR-TB) is less transmissible than drug-susceptible (DS-)TB on a population level is uncertain. Even in the absence of a genetic fitness cost, the transmission potential of individuals with MDR-TB may vary by infectiousness, frequency of contact, or duration of disease. We used a compartmental model to project the progression of MDR-TB epidemics in South Africa and Vietnam under alternative assumptions about the relative transmission efficiency of MDR-TB. Specifically, we considered three scenarios: consistently lower transmission efficiency for MDR-TB than for DS-TB; equal transmission efficiency; and an initial deficit in the transmission efficiency of MDR-TB that closes over time. We calibrated these scenarios with data from drug resistance surveys and projected epidemic trends to 2040. The incidence of MDR-TB was projected to expand in most scenarios, but the degree of expansion depended greatly on the future transmission efficiency of MDR-TB. For example, by 2040, we projected absolute MDR-TB incidence to account for 5% (IQR: 4–9%) of incident TB in South Africa and 14% (IQR: 9–26%) in Vietnam assuming consistently lower MDR-TB transmission efficiency, versus 15% (IQR: 8–27%)and 41% (IQR: 23–62%), respectively, assuming shrinking transmission efficiency deficits. Given future uncertainty, specific responses to halt MDR-TB transmission should be prioritized.

Exploring local realities: Perceptions and experiences of healthcare workers on the management and control of drug-resistant tuberculosis in Addis Ababa, Ethiopia

BACKGROUND

Drug-resistant tuberculosis (DR-TB) remains a major health security threat worldwide. The effectiveness of implementation of DR-TB control strategies has been a subject of research and controversy. In resource-limited settings, using conventional medicine as the only framework to explain DR-TB gives a rather incomplete picture of the disease. This study intended to explore the perceptions and experiences of healthcare workers on the management and control of DR-TB in Addis Ababa, Ethiopia.

METHODS

The study employed a qualitative methodology with an inductive approach and a thematic analysis. It involved in-depth interviews with healthcare workers providing clinical services to DR-TB patients in 10 public healthcare facilities in Addis Ababa, Ethiopia.

RESULTS

A total of 18 healthcare workers participated until data saturation, which included 12 clinical nurses, four health officers and two medical laboratory technicians. The findings show that healthcare workers perceive DR-TB as a growing public health threat in Ethiopia, due to factors such as poverty, poor nutrition, crowded settings, healthcare worker and general public awareness of DR-TB, lack of good governance and culture.

CONCLUSION

The perspectives drawn from the healthcare workers shed more light on the image of DR-TB in a developing country context. It has been shown that understanding DR-TB is not confined to what can be drawn from the sphere of biomedicine. There are also interconnected barriers, which predict a dystopia in the epidemiology of DR-TB. Bringing DR-TB under control requires taking a step back from an overwhelming focus on the biomedical facets of the disease, and employ critical thinking on the wider social and structural forces as equally important targets.