Drug resistance and epidemiological success of modern Mycobacterium tuberculosis lineages in western India.

BACKGROUND: Transmission is contributing to the slow decline of tuberculosis (TB) incidence globally. Drivers of TB transmission in India, the country estimated to carry a quarter of the World's burden, are not well studied. We conducted a genomic epidemiology study to compare epidemiological success, host factors and drug resistance (DR) among the four major Mycobacterium tuberculosis (Mtb) lineages (L1-4) circulating in Pune, India. METHODS: We performed whole-genome sequencing (WGS) of Mtb sputum culture-positive isolates from participants in two prospective cohort studies and predicted genotypic susceptibility using a validated random forest model. We used maximum likelihood estimation to build phylogenies. We compared lineage specific phylogenetic and time-scaled metrics to assess epidemiological success. RESULTS: Of the 642 isolates that underwent WGS, 612 met sequence quality criteria. Most isolates belonged to L3 (44.6%). The majority (61.1%) of multidrug-resistant isolates belonged to L2 (P < 0.001). In molecular dating, L2 demonstrated a higher rate and more recent resistance acquisition. We measured higher clustering, and time-scaled haplotypic density (THD) for L4 and L2 compared to L3 and/or L1 suggesting higher epidemiological success. L4 demonstrated higher THD and clustering (OR 5.1 (95% CI 2.3-12.3) in multivariate models controlling for host factors and DR. CONCLUSION: L2 shows a higher frequency of DR and both L2 and L4 demonstrate evidence of higher epidemiological success than L3 or L1 in the study setting. Our findings highlight the need for contact tracing around TB cases, and heightened surveillance of TB DR in India.

Enabling precision medicine via standard communication of HTS provenance, analysis, and results.

A personalized approach based on a patient's or pathogen's unique genomic sequence is the foundation of precision medicine. Genomic findings must be robust and reproducible, and experimental data capture should adhere to findable, accessible, interoperable, and reusable (FAIR) guiding principles. Moreover, effective precision medicine requires standardized reporting that extends beyond wet-lab procedures to computational methods. The BioCompute framework (https://w3id.org/biocompute/1.3.0) enables standardized reporting of genomic sequence data provenance, including provenance domain, usability domain, execution domain, verification kit, and error domain. This framework facilitates communication and promotes interoperability. Bioinformatics computation instances that employ the BioCompute framework are easily relayed, repeated if needed, and compared by scientists, regulators, test developers, and clinicians. Easing the burden of performing the aforementioned tasks greatly extends the range of practical application. Large clinical trials, precision medicine, and regulatory submissions require a set of agreed upon standards that ensures efficient communication and documentation of genomic analyses. The BioCompute paradigm and the resulting BioCompute Objects (BCOs) offer that standard and are freely accessible as a GitHub organization (https://github.com/biocompute-objects) following the "Open-Stand.org principles for collaborative open standards development." With high-throughput sequencing (HTS) studies communicated using a BCO, regulatory agencies (e.g., Food and Drug Administration [FDA]), diagnostic test developers, researchers, and clinicians can expand collaboration to drive innovation in precision medicine, potentially decreasing the time and cost associated with next-generation sequencing workflow exchange, reporting, and regulatory reviews.

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.

A standardised method for interpreting the association between mutations and phenotypic drug resistance in Mycobacterium tuberculosis.

A clear understanding of the genetic basis of antibiotic resistance in Mycobacterium tuberculosis 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 M. tuberculosis 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.

Tuberculosis diagnostics in 2015: landscape, priorities, needs, and prospects.

In 2015, tuberculosis remains a major global health problem, and drug-resistant tuberculosis is a growing threat. Although tuberculosis diagnosis in many countries is still reliant on older tools, new diagnostics are changing the landscape. Stimulated, in part, by the success and roll out of Xpert MTB/RIF, there is now considerable interest in new technologies. The landscape looks promising, with a robust pipeline of new tools, particularly molecular diagnostics, and well over 50 companies actively engaged in product development. However, new diagnostics are yet to reach scale, and there needs to be greater convergence between diagnostics development and development of shorter-duration tuberculosis drug regimens. Another concern is the relative absence of non-sputum-based diagnostics in the pipeline for children and of biomarker tests for triage, cure, and progression of latent Mycobacterium tuberculosis infection. Several initiatives, described in this supplement, have been launched to further stimulate product development and policy, including assessment of needs and priorities, development of target product profiles, compilation of data on resistance-associated mutations, and assessment of market size and potential for new diagnostics. Advocacy is needed to increase funding for tuberculosis research and development, and governments in high-burden countries must invest more in tuberculosis control to meet post-2015 targets for care, control, and prevention.

Defining the needs for next generation assays for tuberculosis.

To accelerate the fight against tuberculosis, major diagnostic challenges need to be addressed urgently. Post-2015 targets are unlikely to be met without the use of novel diagnostics that are more accurate and can be used closer to where patients first seek care in affordable diagnostic algorithms. This article describes the efforts by the stakeholder community that led to the identification of the high-priority diagnostic needs in tuberculosis. Subsequently target product profiles for the high-priority diagnostic needs were developed and reviewed in a World Health Organization (WHO)-led consensus meeting. The high-priority diagnostic needs included (1) a sputum-based replacement test for smear-microscopy; (2) a non-sputum-based biomarker test for all forms of tuberculosis, ideally suitable for use at levels below microscopy centers; (3) a simple, low cost triage test for use by first-contact care providers as a rule-out test, ideally suitable for use by community health workers; and (4) a rapid drug susceptibility test for use at the microscopy center level. The developed target product profiles, along with complimentary work presented in this supplement, will help to facilitate the interaction between the tuberculosis community and the diagnostics industry with the goal to lead the way toward the post-2015 global tuberculosis targets.

Integration of published information into a resistance-associated mutation database for Mycobacterium tuberculosis.

Tuberculosis remains a major global public health challenge. Although incidence is decreasing, the proportion of drug-resistant cases is increasing. Technical and operational complexities prevent Mycobacterium tuberculosis drug susceptibility phenotyping in the vast majority of new and retreatment cases. The advent of molecular technologies provides an opportunity to obtain results rapidly as compared to phenotypic culture. However, correlations between genetic mutations and resistance to multiple drugs have not been systematically evaluated. Molecular testing of M. tuberculosis sampled from a typical patient continues to provide a partial picture of drug resistance. A database of phenotypic and genotypic testing results, especially where prospectively collected, could document statistically significant associations and may reveal new, predictive molecular patterns. We examine the feasibility of integrating existing molecular and phenotypic drug susceptibility data to identify associations observed across multiple studies and demonstrate potential for well-integrated M. tuberculosis mutation data to reveal actionable findings.

Target product profile of a molecular drug-susceptibility test for use in microscopy centers.

BACKGROUND: Current phenotypic testing for drug resistance in patients with tuberculosis is inadequate primarily with respect to turnaround time. Molecular tests hold the promise of an improved time to diagnosis. METHODS: A target product profile for a molecular drug-susceptibility test (DST) was developed on the basis of a collaborative effort that included opinions gathered from researchers, clinicians, policy makers, and test developers on optimal clinical and operational characteristics in settings of intended use. In addition, the current diagnostic ecosystem and the diagnostic development landscape were mapped. RESULTS: Molecular DSTs for detecting tuberculosis in microscopy centers should ideally evaluate for resistance to rifampin, fluoroquinolones, isoniazid, and pyrazinamide and enable the selection of the most appropriate treatment regimen. Performance characteristics of DSTs need to be optimized, but compromises can be made that depend on the trade-off between a false-positive result and a false-negative result. The operational requirements of a test will vary depending on the site of implementation. However, the most-important considerations pertain to quality control, maintenance and calibration, and the ability to export data. CONCLUSION: This target product profile defines the needs as perceived by the tuberculosis stakeholder community and attempts to provide a means of communication with test developers to ensure that fit-for-purpose DSTs are being developed.

Translating the Tuberculosis Research Agenda: Much Accomplished, but Much More to Be Done.

Despite the availability of effective diagnostics and curative treatment regimens for tuberculosis, millions of people die each year of this disease. The steady global increase in the number of tuberculosis cases caused by multidrug-resistant and extensively drug-resistant strains of Mycobacterium tuberculosis are of major concern, especially in light of the thin tuberculosis drug pipeline. New tuberculosis drugs are undergoing clinical evaluation, and renewed hope comes from fresh approaches to improve treatment outcomes using a range of adjunct host-directed cellular and repurposed drug therapies. Current efforts in developing second-generation and new rapid point-of-care diagnostic assays take advantage of recent genetic and molecular advances. Slow progress in the development of prophylactic and therapeutic vaccines requires increased funding for basic as well as translational research. Although major challenges remain, these can be overcome by cementing our resolve, raising advocacy, bolstering global funder investments, and leveraging more effective collaborations through equitable public-private partnerships.

Perspectives on Advances in Tuberculosis Diagnostics, Drugs, and Vaccines.

Despite concerted efforts over the past 2 decades at developing new diagnostics, drugs, and vaccines with expanding pipelines, tuberculosis remains a global emergency. Several novel diagnostic technologies show promise of better point-of-care rapid tests for tuberculosis including nucleic acid-based amplification tests, imaging, and breath analysis of volatile organic compounds. Advances in new and repurposed drugs for use in multidrug-resistant (MDR) or extensively drug-resistant (XDR) tuberculosis have focused on development of several new drug regimens and their evaluation in clinical trials and now influence World Health Organization guidelines. Since the failure of the MVA85A vaccine 2 years ago, there have been no new tuberculosis vaccine candidates entering clinical testing. The current status quo of the lengthy treatment duration and poor treatment outcomes associated with MDR/XDR tuberculosis and with comorbidity of tuberculosis with human immunodeficiency virus and noncommunicable diseases is unacceptable. New innovations and political and funder commitment for early rapid diagnosis, shortening duration of therapy, improving treatment outcomes, and prevention are urgently required.

Collaborative Effort for a Centralized Worldwide Tuberculosis Relational Sequencing Data Platform.

Continued progress in addressing challenges associated with detection and management of tuberculosis requires new diagnostic tools. These tools must be able to provide rapid and accurate information for detecting resistance to guide selection of the treatment regimen for each patient. To achieve this goal, globally representative genotypic, phenotypic, and clinical data are needed in a standardized and curated data platform. A global partnership of academic institutions, public health agencies, and nongovernmental organizations has been established to develop a tuberculosis relational sequencing data platform (ReSeqTB) that seeks to increase understanding of the genetic basis of resistance by correlating molecular data with results from drug susceptibility testing and, optimally, associated patient outcomes. These data will inform development of new diagnostics, facilitate clinical decision making, and improve surveillance for drug resistance. ReSeqTB offers an opportunity for collaboration to achieve improved patient outcomes and to advance efforts to prevent and control this devastating disease.

Clinical Case Definitions for Classification of Intrathoracic Tuberculosis in Children: An Update.

Consensus case definitions for childhood tuberculosis have been proposed by an international expert panel, aiming to standardize the reporting of cases in research focusing on the diagnosis of intrathoracic tuberculosis in children. These definitions are intended for tuberculosis diagnostic evaluation studies of symptomatic children with clinical suspicion of intrathoracic tuberculosis, and were not intended to predefine inclusion criteria into such studies. Feedback from researchers suggested that further clarification was required and that these case definitions could be further improved. Particular concerns were the perceived complexity and overlap of some case definitions, as well as the potential exclusion of children with acute onset of symptoms or less severe disease. The updated case definitions proposed here incorporate a number of key changes that aim to reduce complexity and improve research performance, while maintaining the original focus on symptomatic children suspected of having intrathoracic tuberculosis. The changes proposed should enhance harmonized classification for intrathoracic tuberculosis disease in children across studies, resulting in greater comparability and the much-needed ability to pool study results.

New government drug repurposing programs: Opportunities and uncertainties.

Drug repurposing can be cheaper and faster than developing new compounds. Yet, it remains underused, partially because of regulatory and intellectual property challenges. Policy-makers in the United States and Europe have created seven drug development programs that aim to overcome these challenges using a variety of different strategies.

Perspectives on introduction and implementation of new point-of-care diagnostic tests.

In recent years, there has been significant investment from both the private and public sectors in the development of diagnostic technologies to meet the need for human immunodeficiency virus (HIV) and tuberculosis testing in low-resource settings. Future investments should ensure that the most appropriate technologies are adopted in settings where they will have a sustainable impact. Achieving these aims requires the involvement of many stakeholders, as their needs, operational constraints, and priorities are often distinct. Here, we discuss these considerations from different perspectives representing those of various stakeholders involved in the development, introduction, and implementation of diagnostic tests. We also discuss some opportunities to address these considerations.

Opportunities and challenges for cost-efficient implementation of new point-of-care diagnostics for HIV and tuberculosis.

Stakeholders agree that supporting high-quality diagnostics is essential if we are to continue to make strides in the fight against human immunodeficiency virus (HIV) and tuberculosis. Despite the need to strengthen existing laboratory infrastructure, which includes expanding and developing new laboratories, there are clear diagnostic needs where conventional laboratory support is insufficient. Regarding HIV, rapid point-of-care (POC) testing for initial HIV diagnosis has been successful, but several needs remain. For tuberculosis, several new diagnostic tests have recently been endorsed by the World Health Organization, but a POC test remains elusive. Human immunodeficiency virus and tuberculosis are coendemic in many high prevalence locations, making parallel diagnosis of these conditions an important consideration. Despite its clear advantages, POC testing has important limitations, and laboratory-based testing will continue to be an important component of future diagnostic networks. Ideally, a strategic deployment plan should be used to define where and how POC technologies can be most efficiently and cost effectively integrated into diagnostic algorithms and existing test networks prior to widespread scale-up. In this fashion, the global community can best harness the tremendous capacity of novel diagnostics in fighting these 2 scourges.

Drug-resistant tuberculosis--current dilemmas, unanswered questions, challenges, and priority needs.

Tuberculosis was declared a global emergency by the World Health Organization (WHO) in 1993. Following the declaration and the promotion in 1995 of directly observed treatment short course (DOTS), a cost-effective strategy to contain the tuberculosis epidemic, nearly 7 million lives have been saved compared with the pre-DOTS era, high cure rates have been achieved in most countries worldwide, and the global incidence of tuberculosis has been in a slow decline since the early 2000s. However, the emergence and spread of multidrug-resistant (MDR) tuberculosis, extensively drug-resistant (XDR) tuberculosis, and more recently, totally drug-resistant tuberculosis pose a threat to global tuberculosis control. Multidrug-resistant tuberculosis is a man-made problem. Laboratory facilities for drug susceptibility testing are inadequate in most tuberculosis-endemic countries, especially in Africa; thus diagnosis is missed, routine surveillance is not implemented, and the actual numbers of global drug-resistant tuberculosis cases have yet to be estimated. This exposes an ominous situation and reveals an urgent need for commitment by national programs to health system improvement because the response to MDR tuberculosis requires strong health services in general. Multidrug-resistant tuberculosis and XDR tuberculosis greatly complicate patient management within resource-poor national tuberculosis programs, reducing treatment efficacy and increasing the cost of treatment to the extent that it could bankrupt healthcare financing in tuberculosis-endemic areas. Why, despite nearly 20 years of WHO-promoted activity and >12 years of MDR tuberculosis-specific activity, has the country response to the drug-resistant tuberculosis epidemic been so ineffectual? The current dilemmas, unanswered questions, operational issues, challenges, and priority needs for global drug resistance screening and surveillance, improved treatment regimens, and management of outcomes and prevention of DR tuberculosis are discussed.

Tuberculosis diagnostics and biomarkers: needs, challenges, recent advances, and opportunities.

Tuberculosis is unique among the major infectious diseases in that it lacks accurate rapid point-of-care diagnostic tests. Failure to control the spread of tuberculosis is largely due to our inability to detect and treat all infectious cases of pulmonary tuberculosis in a timely fashion, allowing continued Mycobacterium tuberculosis transmission within communities. Currently recommended gold-standard diagnostic tests for tuberculosis are laboratory based, and multiple investigations may be necessary over a period of weeks or months before a diagnosis is made. Several new diagnostic tests have recently become available for detecting active tuberculosis disease, screening for latent M. tuberculosis infection, and identifying drug-resistant strains of M. tuberculosis. However, progress toward a robust point-of-care test has been limited, and novel biomarker discovery remains challenging. In the absence of effective prevention strategies, high rates of early case detection and subsequent cure are required for global tuberculosis control. Early case detection is dependent on test accuracy, accessibility, cost, and complexity, but also depends on the political will and funder investment to deliver optimal, sustainable care to those worst affected by the tuberculosis and human immunodeficiency virus epidemics. This review highlights unanswered questions, challenges, recent advances, unresolved operational and technical issues, needs, and opportunities related to tuberculosis diagnostics.

Fosfomycin for Non-Urinary Tract Infections: a systematic review.

Introduction: Although fosfomycin is currently approved for treating urinary tract infections, it is increasingly being used as salvage therapy for various infectious syndromes outside the urinary tract. This systematic review evaluates clinical and microbiological cure rates in patients with bacterial infections not restricted to the urinary tract where fosfomycin was used off-label. Materials and Methods: Articles from two databases (Pubmed and Scopus) were reviewed. The dosage, route, and duration of fosfomycin therapy along with the details of adjunctive antimicrobial agents were noted. The final outcomes captured were clinical or microbiological cures. Results: A total of 649 articles, not including duplicates, were selected for the title and abstract screening. After title and abstract screening, 102 articles were kept for full-text screening. Of the 102 articles, 23 studies (n=1227 patients) were kept in the final analysis. Of the 1227 patients, 301 (25%) received fosfomycin as monotherapy, and the remaining 926 75%) received fosfomycin in combination with at least one other antimicrobial agent. Most of the patients received intravenous fosfomycin (n=1046, 85%). Staphylococcus spp and Enterobacteriaceae were the most common organisms. The pooled clinical and microbiological cure rates were 75% and 84%, respectively. Conclusion: Fosfomycin has moderate clinical success in patients with non-urinary tract infections, especially when used with other antimicrobials. Due to the paucity of randomized controlled trials, fosfomycin's use should be limited to situations where no alternatives are supported by better clinical evidence.

Diagnostic capacities and treatment practices on implantation mycoses: Results from the 2022 WHO global online survey.

Between January and March 2022, WHO conducted a global online survey to collect data on diagnostic capacities and treatment practices in different settings for four implantation mycoses: eumycetoma, actinomycetoma, cutaneous sporotrichosis and chromoblastomycosis. The survey investigated the type of diagnostic methods available in countries at various health system levels (tertiary, secondary, primary level) and the medicines used to treat implantation mycoses, with a view to understanding the level of drug repurposing for treatment of these diseases. 142 respondents from 47 countries, including all continents, contributed data: 60% were from middle-income countries, with 59% working at the tertiary level of the health system and 30% at the secondary level. The results presented in this article provide information on the current diagnostic capacity and treatment trends for both pharmacological and non-pharmacological interventions. In addition, the survey provides insight on refractory case rates, as well as other challenges, such as availability and affordability of medicines, especially in middle-income countries. Although the study has limitations, the survey-collected data confirms that drug repurposing is occurring for all four surveyed implantation mycoses. The implementation of an openly accessible global and/or a national treatment registry for implantation mycoses could contribute to address the gaps in epidemiological information and collect valuable observational data to inform treatment guidelines and clinical research.