Antimicrobial resistance is a major public health problem globally. Likewise, forms of tuberculosis (TB) resistant to first- and second-line TB medicines present a major challenge for patients, ...healthcare workers and healthcare services. In November 2019, the World Health Organization (WHO) convened an independent international expert panel to review new evidence on the treatment of multidrug- (MDR) and rifampicin-resistant (RR) TB, using the Grading of Recommendations Assessment, Development and Evaluation approach.Updated WHO guidelines emerging from this review, published in June 2020, recommend a shorter treatment regimen for patients with MDR/RR-TB not resistant to fluoroquinolones (of 9-11 months), with the inclusion of bedaquiline instead of an injectable agent, making the regimen all oral. For patients with MDR-TB and additional fluoroquinolone resistance, a regimen composed of bedaquiline, pretomanid and linezolid may be used under operational research conditions (6-9 months). Depending on the drug-resistance profile, extent of TB disease or disease severity, a longer (18-20 months) all-oral, individualised treatment regimen may be used. In addition, the review of new data in 2019 allowed the WHO to conclude that there are no major safety concerns on the use of bedaquiline for >6 months' duration, the use of delamanid and bedaquiline together and the use of bedaquiline during pregnancy, although formal recommendations were not made on these topics.The 2020 revision has highlighted the ongoing need for high-quality evidence and has reiterated the need for clinical trials and other research studies to contribute to the development of evidence-based policy.
Abstract
Mycobacterium tuberculosis
is a clonal pathogen proposed to have co-evolved with its human host for millennia, yet our understanding of its genomic diversity and biogeography remains ...incomplete. Here we use a combination of phylogenetics and dimensionality reduction to reevaluate the population structure of
M. tuberculosis
, providing an in-depth analysis of the ancient Indo-Oceanic Lineage 1 and the modern Central Asian Lineage 3, and expanding our understanding of Lineages 2 and 4. We assess sub-lineages using genomic sequences from 4939 pan-susceptible strains, and find 30 new genetically distinct clades that we validate in a dataset of 4645 independent isolates. We find a consistent geographically restricted or unrestricted pattern for 20 groups, including three groups of Lineage 1. The distribution of terminal branch lengths across the
M. tuberculosis
phylogeny supports the hypothesis of a higher transmissibility of Lineages 2 and 4, in comparison with Lineages 3 and 1, on a global scale. We define an expanded barcode of 95 single nucleotide substitutions that allows rapid identification of 69
M. tuberculosis
sub-lineages and 26 additional internal groups. Our results paint a higher resolution picture of the
M. tuberculosis
phylogeny and biogeography.
A clear understanding of the genetic basis of antibiotic resistance in
is required to accelerate the development of rapid drug susceptibility testing methods based on genetic sequence.Raw ...genotype-phenotype correlation data were extracted as part of a comprehensive systematic review to develop a standardised analytical approach for interpreting resistance associated mutations for rifampicin, isoniazid, ofloxacin/levofloxacin, moxifloxacin, amikacin, kanamycin, capreomycin, streptomycin, ethionamide/prothionamide and pyrazinamide. Mutation frequencies in resistant and susceptible isolates were calculated, together with novel statistical measures to classify mutations as high, moderate, minimal or indeterminate confidence for predicting resistance.We identified 286 confidence-graded mutations associated with resistance. Compared to phenotypic methods, sensitivity (95% CI) for rifampicin was 90.3% (89.6-90.9%), while for isoniazid it was 78.2% (77.4-79.0%) and their specificities were 96.3% (95.7-96.8%) and 94.4% (93.1-95.5%), respectively. For second-line drugs, sensitivity varied from 67.4% (64.1-70.6%) for capreomycin to 88.2% (85.1-90.9%) for moxifloxacin, with specificity ranging from 90.0% (87.1-92.5%) for moxifloxacin to 99.5% (99.0-99.8%) for amikacin.This study provides a standardised and comprehensive approach for the interpretation of mutations as predictors of
drug-resistant phenotypes. These data have implications for the clinical interpretation of molecular diagnostics and next-generation sequencing as well as efficient individualised therapy for patients with drug-resistant tuberculosis.
Summary Although progress has been made to reduce global incidence of drug-susceptible tuberculosis, the emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis ...during the past decade threatens to undermine these advances. However, countries are responding far too slowly. Of the estimated 440 000 cases of MDR tuberculosis that occurred in 2008, only 7% were identified and reported to WHO. Of these cases, only a fifth were treated according to WHO standards. Although treatment of MDR and XDR tuberculosis is possible with currently available diagnostic techniques and drugs, the treatment course is substantially more costly and laborious than for drug-susceptible tuberculosis, with higher rates of treatment failure and mortality. Nonetheless, a few countries provide examples of how existing technologies can be used to reverse the epidemic of MDR tuberculosis within a decade. Major improvements in laboratory capacity, infection control, performance of tuberculosis control programmes, and treatment regimens for both drug-susceptible and drug-resistant disease will be needed, together with a massive scale-up in diagnosis and treatment of MDR and XDR tuberculosis to prevent drug-resistant strains from becoming the dominant form of tuberculosis. New diagnostic tests and drugs are likely to become available during the next few years and should accelerate control of MDR and XDR tuberculosis. Equally important, especially in the highest-burden countries of India, China, and Russia, will be a commitment to tuberculosis control including improvements in national policies and health systems that remove financial barriers to treatment, encourage rational drug use, and create the infrastructure necessary to manage MDR tuberculosis on a national scale.
Whole genome sequencing (WGS) of Mycobacterium tuberculosis has rapidly progressed from a research tool to a clinical application for the diagnosis and management of tuberculosis and in public health ...surveillance. This development has been facilitated by drastic drops in cost, advances in technology and concerted efforts to translate sequencing data into actionable information. There is, however, a risk that, in the absence of a consensus and international standards, the widespread use of WGS technology may result in data and processes that lack harmonization, comparability and validation. In this Review, we outline the current landscape of WGS pipelines and applications, and set out best practices for M. tuberculosis WGS, including standards for bioinformatics pipelines, curated repositories of resistance-causing variants, phylogenetic analyses, quality control and standardized reporting.
Summary Background The Global Project on Anti-Tuberculosis Drug Resistance has been gathering data since 1994. This study provides the latest data on the extent of drug resistance worldwide. Methods ...Data for drug susceptibility were gathered from 90 726 patients in 83 countries and territories between 2002 and 2007. Standardised collection of results enabled comparison both between and within countries. Where possible, data for HIV status and resistance to second-line drugs were also obtained. Laboratory data were quality assured by the Supranational Tuberculosis Reference Laboratory Network. Findings The median prevalence of resistance to any drug in new cases of tuberculosis was 11·1% (IQR 7·0–22·3). The prevalence of multidrug resistance in new tuberculosis cases ranged from 0% in eight countries to 7% in two provinces in China, 11·1% in Northern Mariana Islands (although reporting only two cases), and between 6·8% and 22·3% in nine countries of the former Soviet Union, including 19·4% in Moldova and 22·3% in Baku, Azerbaijan (median for countries surveyed 1·6%, IQR 0·6–3·9). Trend analysis showed that between 1994 and 2007, the prevalence of multidrug-resistant (MDR) tuberculosis in new cases increased substantially in South Korea and in Tomsk Oblast and Orel Oblast, Russia, but was stable in Estonia and Latvia. The prevalence of MDR tuberculosis in all tuberculosis cases decreased in Hong Kong and the USA. 37 countries and territories reported representative data on extensively drug-resistant (XDR) tuberculosis. Five countries, all from the former Soviet Union, reported 25 cases or more of XDR tuberculosis each, with prevalence among MDR-tuberculosis cases ranging between 6·6% and 23·7%. Interpretation MDR tuberculosis remains a threat to tuberculosis control in provinces in China and countries of the former Soviet Union. Data on drug resistance are unavailable in many countries, especially in Africa, emphasising the need to develop easier methods for surveillance of resistance in tuberculosis. Funding Global Project: United States Agency for International Development and Eli Lilly and Company. Drug resistance surveys: national tuberculosis programmes, the Government of the Netherlands, the Global Fund to Fight AIDS, Tuberculosis and Malaria, Japan International Cooperation Agency, and Kreditanstalt für Wiederaufbau.
Tuberculosis (TB) is a major cause of ill health worldwide. Until the coronavirus (COVID-19) pandemic, TB was the leading cause of death from a single infectious agent. COVID-19 has caused enormous ...health, social and economic upheavals since 2020, impairing access to essential TB services. In marked contrast to the steady global increase in TB detection between 2017 and 2019, TB notifications dropped substantially in 2020 compared with 2019 (-18%), with only a partial recovery in 2021. TB epidemiology worsened during the pandemic: the estimated 10.6 million people who fell ill with TB worldwide in 2021 is an increase of 4.5% from the previous year, reversing many years of slow decline. The annual number of TB deaths worldwide fell steadily between 2005 and 2019, reaching 1.4 million in 2019, but this trend was reversed in 2020 (1.5 million), and by 2021 global TB deaths were back to the level of 2017 (1.6 million). Intensified efforts backed by increased funding are urgently required to reverse the negative impacts of COVID-19 on TB worldwide, made more pressing by ongoing conflicts, a global energy crisis and uncertainties in food security that are likely to worsen the broader determinants of TB.
To present a global update of drug-resistant tuberculosis (TB) and explore trends in 1994-2010.
Data on drug resistance among new and previously treated TB patients, as reported by countries to the ...World Health Organization, were analysed. Such data are collected through surveys of a representative sample of TB patients or surveillance systems based on routine drug susceptibility testing. Associations between multidrug-resistant TB (MDR-TB) and human immunodeficiency virus (HIV) infection and sex were explored through logistic regression.
In 2007-2010, 80 countries and 8 territories reported surveillance data. MDR-TB among new and previously treated cases was highest in the Russian Federation (Murmansk oblast, 28.9%) and the Republic of Moldova (65.1%), respectively. In three former Soviet Union countries and South Africa, more than 10% of the cases of MDR-TB were extensively drug-resistant. Globally, in 1994 to 2010 multidrug resistance was observed in 3.4% (95% confidence interval, CI: 1.9-5.0) of all new TB cases and in 19.8% (95% CI: 14.4-25.1) of previously treated TB cases. No overall associations between MDR-TB and HIV infection (odds ratio, OR: 1.4; 95% CI: 0.7-3.0) or sex (OR: 1.1; 95% CI: 0.8-1.4) were found. Between 1994 and 2010, MDR-TB rates in the general population increased in Botswana, Peru, the Republic of Korea and declined in Estonia, Latvia and the United States of America.
The highest global rates of MDR-TB ever reported were documented in 2009 and 2010. Trends in MDR-TB are still unclear in most settings. Better surveillance or survey data are required, especially from Africa and India.
Tuberculosis (TB) remains a major public health challenge and one of the leading infectious killers in the world 1. Approximately one-fourth of the world's population is estimated to be infected with ...TB bacilli, creating a large pool of individuals who can develop TB and die from it in the coming years 2, 3. In the absence of an effective vaccine, measures to diagnose and treat both TB disease and TB infection remain pivotal to reduce global TB incidence to levels envisaged by the End TB Strategy of the World Health Organization (WHO) and other international commitments 4, 5. Giving medication to treat TB infection, known as TB preventive treatment (TPT), is an established part of care for people living with HIV, contacts of TB patients, people on immunotherapy and others at risk of developing TB 6. The effectiveness of TPT depends on the correct identification of people who would most benefit from it, the use of regimens of proven efficacy and maximising adherence to treatment to the end. Unless these measures are implemented consistently, treatment may have negative repercussions on TB transmission and healthcare costs 7.
Country reports to WHO show low TB preventive treatment (TPT) coverage in contacts of people with TB, below global targets. More efforts are needed to find and evaluate TB contacts, help them access better regimens and complete TPT.
https://bit.ly/3sp0FA3
The emergence and dissemination of drug-resistant
Mycobacterium tuberculosis
is a global threat to health. In this report, surveillance of drug-resistant tuberculosis during the past 20 years is ...described.
Antimicrobial resistance represents a major threat to global health and security. In 2014, the World Health Assembly called on all nations and the international community to take every necessary measure to control it, including surveillance of its emergence and spread.
1
The development of drug resistance in
Mycobacterium tuberculosis
was first documented in the late 1940s, soon after antibiotic therapy was introduced for tuberculosis treatment.
2
It quickly became obvious that combination chemotherapy could prevent the emergence of drug resistance
3
and that patients infected with drug-resistant strains were less likely to be cured.
4
Nevertheless, it was only in the early 1990s that . . .
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