Rifampin-resistant Tuberculosis Research Articles

Economic implications of novel regimens for tuberculosis treatment in three high-burden countries: a modelling analysis.

With numerous trials investigating novel drug combinations to treat tuberculosis, we aimed to evaluate the extent to which future improvements in tuberculosis treatment regimens could offset potential increases in drug costs. In this modelling analysis, we used an ingredients-based approach to estimate prices at which novel regimens for rifampin-susceptible and rifampin-resistant tuberculosis treatment would be cost-neutral or cost-effective compared with standards of care in India, the Philippines, and South Africa. We modelled regimens meeting targets set in the WHO's 2023 Target Regimen Profiles (TRPs). Our decision-analytical model tracked cohorts of adults initiating rifampin-susceptible or rifampin-resistant tuberculosis treatment, simulating their health outcomes and costs accumulated during and following treatment under standard-of-care and novel regimen scenarios. Price thresholds included short-term cost-neutrality (considering only savings accrued during treatment), medium-term cost-neutrality (additionally considering savings from averted retreatments and secondary cases), and cost-effectiveness (incorporating willingness-to-pay for improved health outcomes). Total medium-term costs per person treated using standard-of-care regimens were estimated at US$450 (95% uncertainty interval 310-630) in India, $560 (350-860) in the Philippines, and $730 (530-1090) in South Africa for rifampin-susceptible tuberculosis (current drug costs $46) and $2100 (1590-2810) in India, $2610 (2090-3280) in the Philippines, and $3790 (3090-4630) in South Africa for rifampin-resistant tuberculosis (current drug costs $432). A rifampin-susceptible tuberculosis regimen meeting the optimal targets defined in the TRPs could be cost-neutral in the short term at drug costs of $140 (90-210) per full course in India, $230 (130-380) in the Philippines, and $280 (180-460) in South Africa. For rifampin-resistant tuberculosis, short-term cost-neutral thresholds were higher with $930 (720-1230) in India, $1180 (980-1430) in the Philippines, and $1480 (1230-1780) in South Africa. Medium-term cost-neutral prices were approximately $50-100 higher than short-term cost-neutral prices for rifampin-susceptible tuberculosis and $250-550 higher for rifampin-resistant tuberculosis. Health system cost-neutral prices that excluded patient-borne costs were 45-70% lower (rifampin-susceptible regimens) and 15-50% lower (rifampin-resistant regimens) than the cost-neutral prices that included patient costs. Cost-effective prices were substantially higher. Shorter duration was the most important driver of medium-term savings with novel regimens, followed by ease of adherence. Improved tuberculosis regimens, particularly shorter regimens or those that facilitate better adherence, could reduce overall costs, potentially offsetting higher prices. WHO.

Retrospective analysis of diagnosis and treatment of tuberculosis in designated medical institutions in China from 2017 to 2022

Objective: To understand the status of tuberculosis diagnosis and treatment capacity and the development and changes of tuberculosis diagnosis and treatment in provincial and municipal designated medical institutions in China from 2017 to 2022, so as to provide a basis for the formulation of relevant policies for the improvement and development of designated medical institutions for tuberculosis and the tuberculosis prevention and treatment service system, and to provide reasonable support for further strengthening the capacity of designated medical institutions for tuberculosis. Methods: This study was initiated and carried out by Beijing Chest Hospital affiliated to Capital Medical University/Clinical Center for Tuberculosis Prevention and Control of China CDC (hereinafter referred to as "Clinical Center") by means of questionnaire survey, and the investigation was carried out from March to November 2023. During this period, the clinical center distributed questionnaires to the hospital member units of "Beijing Tuberculosis Diagnosis and Treatment Technology Innovation Alliance", retrospectively collected their tuberculosis-related diagnosis and treatment data from 2017 to 2022, and used descriptive statistical methods to analyze the number of tuberculosis beds, outpatients and hospitalizations in medical institutions. The results were expressed in absolute numbers (percentages), and three-line tables, bar charts and line charts were drawn to describe the analysis results and changing trends. Results: The 54 medical institutions surveyed in this survey included 21 provincial-level designated medical institutions and 33 prefecture-level designated medical institutions. Most medical institutions have set up clinical departments, auxiliary departments and functional departments to undertake public health tasks of infectious diseases. The tuberculosis laboratory in the hospital has a comprehensive ability and has the detection technology needed for most tuberculosis diagnosis; The number of tuberculosis beds, children's tuberculosis beds and ICU beds all showed an increasing trend from 2017 to 2022. The proportion of tuberculosis beds in the hospital decreased slightly, from 39.31% in 2017 to 34.76% in 2022, showing a slight downward trend. Compared with the hospital surveyed, the number of tuberculosis outpatients in 2019 was 562 029, and the number of outpatients in 2020-2022 was 462 328, 519 630 and 424 069 respectively, which was significantly lower than that in 2019. The number of tuberculosis outpatients in medical institutions decreased significantly from 2020 to 2022. By analyzing the proportion of patients with different types of tuberculosis, the proportion of sensitive tuberculosis outpatients in 2017-2022 decreased from 84.49% in 2017 to 78.05% in 2022, showing a downward trend year by year. The proportion of patients with multidrug-resistant/ rifampin-resistant tuberculosis increased from 2.03% in 2017 to 7.18% in 2022. From 2017 to 2019, the total number of inpatients with tuberculosis showed an upward trend. Compared with 2019, the number of inpatients in 2020, 2021 and 2022 showed a downward trend, and the decline in 2020 was large (down 14.94% compared with 2019). Among the inpatients, the absolute number and proportion of patients with sensitive pulmonary tuberculosis remained relatively stable, and the number and proportion of inpatients with multidrug-resistant/rifampin-resistant pulmonary tuberculosis increased year by year. Conclusions: Most medical institutions have the capacity to carry out routine diagnosis and treatment of tuberculosis, but the public health function needs to be strengthened. The transformation of medical institutions requires proper guidance and adequate support. During 2019-2022, most medical institutions were affected by the COVID-19 epidemic, and their tuberculosis diagnosis and treatment work also changed to varying degrees. During this period, hospitals took various measures to overcome difficulties and tried their best to maintain the normal development of tuberculosis diagnosis and treatment, and the tuberculosis diagnosis and treatment work of various institutions gradually resumed in 2022.

Bedaquiline Resistance after Effective Treatment of Multidrug-Resistant Tuberculosis, Namibia.

Bedaquiline is currently a key drug for treating multidrug-resistant or rifampin-resistant tuberculosis. We report and discuss the unusual development of resistance to bedaquiline in a teenager in Namibia, despite an optimal background regimen and adherence. The report highlights the risk for bedaquiline resistance development and the need for rapid drug-resistance testing.

(Invited) Lab-in-a-Tube Design Enables a Rapid Diagnosis of Infectious Disease

Disease diagnosis increasingly relies on molecular tests that are often limited by infrastructure constraints. For example, tuberculosis (TB) remains a leading cause of death from infectious disease, but an estimated 4.2 million (39.6%) new TB cases were not diagnosed in 2021 and only 57% were confirmed by gold-standard sputum culture or PCR-based tests, partially due to limited accessibility. New point-of-care tests are thus urgently needed to address coverage disparities for chronic, malignant, and infectious diseases.We have developed two smartphone-based assays that can address two diagnostic shortfalls: an on-chip interferon-gamma release assay (IGRA) that detects a T-cell activation response induced by pathogen antigens in fingerstick blood samples, and a lab-in-tube assay that employs CRISPR to sensitively detect pathogen DNA in sputum. Both approaches translate current diagnostic approaches to point-of-care devices that require minimal equipment, user expertise, and time.Results from our on-chip IGRA also correlated with clinical IGRA results when we employed two proteins associated with TNF-alpha receptor signaling (4-1BB and OX-40) to analyze T-cell activation, indicating this approach could detect infections in individuals with compromised interferon-gamma responses; as observed in HIV patients, who are at increased risk for TB. On-chip IGRA results from a SARS-CoV-2-specific assay also corresponded with both infection and vaccination history, suggesting this data could be employed as a high-throughput, high-capacity test to evaluate the effect of vaccination or previous infection to confer a protective immune response, evaluate its change over time, and predict the response to new variant strains to guide healthcare decisions. Mitogen-induced results could also guide immunotherapy decisions, as reduced IGRA values in patients receiving immune checkpoint inhibitors predict poor treatment response, reduced progression-free survival, and increased risk for interstitial pneumonia, while their change after adoptive T-cell therapy can be an independent predictor for overall survival. Results from our lab-in-tube TB DNA assay also had robust diagnostic performance when compared to gold-standard clinical assays but lacked their more extensive personnel, workflow, and infrastructure requirements and were performed in a closed-tube system that protected user from exposure to infectious material. This lab-in-tube approach also permits parallel multiplex analyses to be performed in a single tube, and thus can be employed to detect mutations associated with drug-resistance to guide treatment decisions. For example, we found that an assay with an optimized guide RNA accurately detected a single-nucleotide polymorphism (rpoB S450L) responsible for the majority of rifampin-resistant TB cases.Both these self-contained handheld devices can employ lyophilized reagents to limit cold-chain concerns, can be readily adapted to diagnose other disease conditions by substituting other disease-specific antibodies or guide RNAs, use rechargeable batteries to avoid infrastructure limitations, and can directly transmit results to central sites to improve disease control efforts.

Association of indicators of extensive disease and rifampin-resistant tuberculosis treatment outcomes: an individual participant data meta-analysis

BackgroundIndicators of extensive disease—acid fast bacilli (AFB) smear positivity and lung cavitation—have been inconsistently associated with clinical rifampin-resistant/multidrug-resistant tuberculosis (RR/MDR-TB) outcomes. We evaluated the association of these indicators with end-of-treatment...

Comparative evaluation of critical concentrations for detecting borderline rifampin resistance in Mycobacterium tuberculosis

Background: Rifampin plays an important role in tuberculosis treatment. In recent years, the introduction of molecular testing techniques has enabled the rapid detection of rifampin resistance, leading to discrepancies with conventional methods. The World Health Organization (WHO) has analyzed mutations in the rpoB gene that induce rifampin resistance and identified certain mutations causing borderline resistance, which are often undetected using conventional tests. Consequently, the WHO has lowered the rifampin resistance criterion concentration from 1.0 to 0.5 μg/mL in 7H10 and MGIT 960. The present study aimed to evaluate the impact of this change in critical concentration on the detection of borderline rifampin resistance in Mycobacterium tuberculosis. Methods: Tuberculosis strains submitted for antituberculosis drug susceptibility testing from May 2021–2022 were analyzed. Three institutions participated; the Seoul Clinical Laboratories used the agar proportion method, whereas the Samsung Medical Center and Seoul National University Bundang Hospital utilized the MGIT 960 system to test both the original and revised concentrations. Mutations were confirmed through rpoB gene sequencing for strains showing discrepancies. Results: A total of 1,596 valid susceptibility tests were conducted during the study period. Rifampin resistance was detected in 35 cases (2.19%) at 1.0 μg/mL and in 38 cases (2.38%) at 0.5 μg/mL, whereas isoniazid resistance was observed in 158 cases (9.90%). Among the three rifampin discrepancy strains, one harbored an H445L mutation, whereas the remaining two exhibited an L452P mutation. These mutations were classified as borderline resistant. Conclusion: Applying the new rifampin critical concentration resulted in a 0.19% increase in resistance rate and an 8.57% increase in detection cases. Additionally, despite testing with large number of rifampin-susceptible strains, no false resistance results were obtained. Therefore, the application of the new critical concentration is considered beneficial for the management of rifampin-resistant tuberculosis.

The Impact of Preventive Treatment for Multidrug- and Rifampin-Resistant Tuberculosis Exceeds Trial-Based Estimates.

Several clinical trials of tuberculosis preventive treatment (TPT) for household contacts of patients with multidrug- or rifampin-resistant tuberculosis (MDR/RR-TB) are nearing completion. The potential benefits of delivering TPT to MDR/RR-TB contacts extend beyond the outcomes that clinical trials can measure. We developed an agent-based, household-structured TB and MDR/RR-TB transmission model, calibrated to an illustrative setting in India. We simulated contact investigation in households of patients with MDR/RR-TB, comparing an MDR/RR-TPT regimen (assuming 6-month duration, 70% efficacy) and associated active case finding against alternatives of contact investigation without TPT or no household intervention. We simulated the TB and MDR/RR-TB incidence averted relative to placebo over 2 years, as measurable by a typical trial, as well as the incidence averted over a longer time horizon, in the broader population, and relative to no contact investigation. Observing TPT and placebo recipients for 2 years as in a typical trial, MDR/RR-TPT was measured to prevent 72% (interquartile range, 45%-100%) of incident MDR/RR-TB among recipients; the median number needed to treat (NNT) to prevent 1 MDR/RR-TB case was 73, compared to placebo. This NNT decreased to 54 with 13-18 years of observation, to 27 when downstream transmission effects were also considered, and to 12 when the effects of active TB screening were included by comparing to a no-household-contact-intervention scenario. If forthcoming trial results demonstrate efficacy, the long-term population impact of TPT for MDR/RR-TB-including the large effect of increased active TB detection among MDR/RR-TB contacts-could be much greater than suggested by trial outcomes alone.

Shorter Oral Regimen for Multidrug Resistant Tuberculosis in South Korea

The treatment of multidrug- and rifampin-resistant tuberculosis (MDR/RR-TB) poses significant challenges, including frequent adverse drug reactions associated with complex treatment regimens involving multiple drugs administered over prolonged periods. However, recent clinical trials, such as Nix-TB, ZeNix, NExT, MDR-END, TB-PRACTECAL, and BEAT-India, have demonstrated that shorter oral regimens yield superior outcomes compared with conventional approaches. Furthermore, the World Health Organization guidelines for MDR/RR-TB treatment recommend a 6-month all-oral regimen that includes bedaquiline, pretomanid, linezolid, and moxifloxacin. However, the implementation of these shorter oral regimens in South Korea requires careful consideration. Health insurance coverage policies must be reviewed to include new TB drugs, such as pretomanid. The optimal dosage and treatment duration of linezolid should be determined to minimize side effects and prevent drug resistance; moreover, alternative regimens should be identified for patients who discontinue linezolid because of adverse drug reactions.

Multi-drug resistant and rifampin-resistant tuberculosis in transplant recipients.

Management of multidrug-resistant (MDR) and rifampin-resistant (RR) tuberculosis is challenging. Data on transplant recipients is limited. We reviewed published literature to examine treatment choices, outcomes, and adverse effects from MDR-TB/RR-TB treatment in transplant recipients. Multiple databases from inception to 12/2022 were reviewed using the keywords "drug-resistant TB" or "drug-resistant tuberculosis" or "multidrug-resistant TB" or "multidrug-resistant tuberculosis". MDR-TB was defined as resistance to isoniazid (H) and rifampin (R), and RR if resistant to rifampin alone. Cases without patient-level data and reports which did not describe treatment and/or outcomes for MDR-TB were excluded. A total of 12 patients (10 solid organ transplants and two hematopoietic cell transplants) were included. Of these, 11 were MDR-TB and one was RR-TB. Seven recipients were male. The median age was 41.5 (range 16-60) years. Pre-transplant evaluation for the majority (8/12, 66.7%) did not reveal a prior history of TB or TB treatment, but 9/12 were from TB intermediate or high-burden countries. Seven patients were initially treated with the quadruple first-line anti-TB regimen. Those who had early RR confirmation (5/12) via Xpert MTB/RIF assay were initiated on alternative therapies. Final regimens were individualized based on susceptibility profiles and tolerability. Adverse events were reported in seven recipients, including acute kidney injury (n = 3), cytopenias (n = 3), and jaundice (n = 2). Four recipients died, with two deaths attributable to TB. The remaining eight patients who survived had functioning allografts at the last follow-up. MDR-TB treatment in transplant recipients is associated with many complications. Xpert MTB/RIF detected RR early and guided early empiric therapy.

Implementation of Bedaquiline, Pretomanid, and Linezolid in the United States: Experience Using a Novel All-Oral Treatment Regimen for Treatment of Rifampin-Resistant or Rifampin-Intolerant Tuberculosis Disease.

Rifampin-resistant tuberculosis is a leading cause of morbidity worldwide; only one-third of persons start treatment, and outcomes are often inadequate. Several trials demonstrate 90% efficacy using an all-oral, 6-month regimen of bedaquiline, pretomanid, and linezolid (BPaL), but significant toxicity occurred using 1200-mg linezolid. After US Food and Drug Administration approval in 2019, some US clinicians rapidly implemented BPaL using an initial 600-mg linezolid dose adjusted by serum drug concentrations and clinical monitoring. Data from US patients treated with BPaL between 14 October 2019 and 30 April 2022 were compiled and analyzed by the BPaL Implementation Group (BIG), including baseline examination and laboratory, electrocardiographic, and clinical monitoring throughout treatment and follow-up. Linezolid dosing and clinical management was provider driven, and most patients had linezolid adjusted by therapeutic drug monitoring. Of 70 patients starting BPaL, 2 changed to rifampin-based therapy, 68 (97.1%) completed BPaL, and 2 of the 68 (2.9%) experienced relapse after completion. Using an initial 600-mg linezolid dose daily adjusted by therapeutic drug monitoring and careful clinical and laboratory monitoring for adverse effects, supportive care, and expert consultation throughout BPaL treatment, 3 patients (4.4%) with hematologic toxicity and 4 (5.9%) with neurotoxicity required a change in linezolid dose or frequency. The median BPaL duration was 6 months. BPaL has transformed treatment for rifampin-resistant or intolerant tuberculosis. In this cohort, effective treatment required less than half the duration recommended in 2019 US guidelines for drug-resistant tuberculosis. Use of individualized linezolid dosing and monitoring likely enhanced safety and treatment completion. The BIG cohort demonstrates that early implementation of new tuberculosis treatments in the United States is feasible.

Tuberculosis in migrants: epidemiology, resistance and outcome in Milan, Italy

Background Human migration and the ever-changing geopolitical scenarios are redefining the epidemiology and the management of tuberculosis (TB), especially in low-TB burden countries welcoming high rates of people from high-TB burden countries. Methods We conducted an observational retrospective mono-centric study in a Northern-Italy TB reference centre from 1 January 1990 to 31 December 2019, focusing on the differences in epidemiology, resistance patterns and treatment outcomes between Italians and migrants with active TB. Data were collected from medical records. Results A total of 10555 patients were included, 4614 Italians and 5941 migrants. Among migrants, higher rates of rifampin-resistant (RR) or multidrug-resistant (MDR) TB were reported, as well as higher rates of loss to follow-up. Among Italians, higher mortality rates and a higher number of extrapulmonary TB cases were found. Conclusion Our study describes one of the largest cohorts of patients with active TB in Italy, highlighting the need for tailored approaches in native and migrant populations.

Ability of the MeltPro MTB/PZA Assay to Detect Susceptibility to Pyrazinamide in Rifampin-Resistant Tuberculosis Patients.

Prediction of susceptibility to pyrazinamide (PZA) directly from sputum has been challenging. The MeltPro MTB/PZA assay, based on melting curve analysis, can simultaneously detect Mycobacterium tuberculosis and the resistance to PZA from sputum. We aimed to evaluate the MeltPro MTB/PZA assay to predict PZA resistance among rifampin-resistant tuberculosis (RR-TB) patients. We prospectively enrolled RR-TB patients in the registered trials, and their baseline sputum samples were obtained to perform the assay and culture. DNA sequencing of culture isolates was analyzed and used as the reference standard. Sanger sequencing was performed for samples with discrepant results between next-generation sequencing (NGS) and the investigational assay. The main analysis was conducted in the population of patients with interpretable results by both NGS and the assay. A total of 239 patients with RR-TB were screened, and 220 underwent the MeltPro MTB/PZA assay. The assay provided no information for 25 of 220 patients (11.4%). Among the remaining 195 patients, 13 had negative culture or insufficient raw NGS sequencing data, and 15 had indeterminate assay results. A total of 167 patients were included in the main analysis. Against DNA sequencing, the sensitivity, specificity, and negative predictive value of the assay for detecting resistance to PZA were 91.4% (95% confidence interval [CI], 87.1% to 95.6%), 89.9% (95% CI, 85.3% to 94.5%), and 95.2% (95% CI, 91.9% to 98.4%), respectively. In conclusion, the MeltPro MTB/PZA assay is a fast semiautomatic molecular platform to rapidly predict resistance to PZA from sputum and holds promise as a screening tool with satisfactory sensitivity. IMPORTANCE This study evaluated the accuracy of the MeltPro MTB/PZA assay at detecting the presence of PZA resistance through registered clinical trials. Compared to DNA sequencing, the assay had high sensitivity and negative predictive value, suggesting its potential utility as a screening tool in clinical practice. The assay could serve as an ideal primary screening tool in low PZA-resistant M. tuberculosis prevalence settings and could be used as an additional test to identify PZA resistance rapidly and initially in the RR-TB population.

Infectious Diseases: What You May Have Missed in 2022.

In 2022, COVID-19 remained the infectious disease at the top of most internal medicine physicians' minds. However, it was not the only infectious disease that was the topic of clinically relevant research that year. This article highlights some important infectious disease evidence unrelated to COVID-19 that was published in 2022. The literature was screened for sound new evidence relevant to internal medicine specialists and subspecialists whose focus of practice is not infectious diseases. The publications highlighted relate to various organisms in different patient populations. One article provides insight into the role of Helicobacter pylori eradication in the treatment of functional dyspepsia. The descriptive epidemiology of bacterial (Staphylococcus aureus) and viral (mpox) infections are the focus of 2 other articles. Several articles address the management of resistant and difficult-to-treat infections: multidrug-resistant gram-negative infections, resistant HIV-1, rifampin-resistant tuberculosis, cryptococcal meningitis, and invasive fungal infection in the setting of neutropenia. Another article provides data on effective HIV preexposure prophylaxis in women, an understudied population. Finally, given the urgent need to reduce inappropriate use of antibiotics, an article on antibiotic stewardship for hospitalized patients with presumed sepsis in a non-intensive care unit setting is also included.

Factors associated with prevalent Mycobacterium tuberculosis infection and disease among adolescents and adults exposed to rifampin-resistant tuberculosis in the household.

Understanding factors associated with prevalent Mycobacterium tuberculosis infection and prevalent TB disease in household contacts of patients with drug-resistant tuberculosis (TB) may be useful for TB program staff conducting contact investigations. Using data from a cross-sectional study that enrolled index participants with rifampin-resistant pulmonary TB and their household contacts (HHCs), we evaluated HHCs age ≥15 years for factors associated with two outcomes: Mycobacterium tuberculosis infection and TB disease. Among HHCs who were not already diagnosed with current active TB disease by the TB program, Mycobacterium tuberculosis infection was determined by interferon-gamma release assay (IGRA). TB disease was adjudicated centrally. We fitted logistic regression models using generalized estimating equations. Seven hundred twelve HHCs age ≥15 years enrolled from 279 households in eight high-TB burden countries were a median age of 34 years, 63% female, 22% current smokers and 8% previous smokers, 8% HIV-positive, and 11% previously treated for TB. Of 686 with determinate IGRA results, 471 tested IGRA positive (prevalence 68.8% (95% Confidence Interval: 64.6%, 72.8%)). Multivariable modeling showed IGRA positivity was more common in HHCs aged 25-49 years; reporting prior TB treatment; reporting incarceration, substance use, and/or a period of daily alcohol use in the past 12 months; sharing a sleeping room or more evenings spent with the index participant; living with smokers; or living in a home of materials typical of low socioeconomic status. Forty-six (6.5% (95% Confidence Interval: 4.6%, 9.0%)) HHCs age ≥15 years had prevalent TB disease. Multivariable modeling showed higher prevalence of TB disease among HHCs aged ≥50 years; reporting current or previous smoking; reporting a period of daily alcohol use in the past 12 months; and reporting prior TB treatment. We identified overlapping and distinct characteristics associated with Mycobacterium tuberculosis infection and TB disease that may be useful for those conducting household TB investigations.

A 24-Week, All-Oral Regimen for Rifampin-Resistant Tuberculosis

BackgroundIn patients with rifampin-resistant tuberculosis, all-oral treatment regimens that are more effective, shorter, and have a more acceptable side-effect profile than current regimens are needed.MethodsWe conducted an open-label, phase 2–3, multicenter, randomized, controlled, noninferiority trial to evaluate the efficacy and safety of three 24-week, all-oral regimens for the treatment of rifampin-resistant tuberculosis. Patients in Belarus, South Africa, and Uzbekistan who were 15 years of age or older and had rifampin-resistant pulmonary tuberculosis were enrolled. In stage 2 of the trial, a 24-week regimen of bedaquiline, pretomanid, linezolid, and moxifloxacin (BPaLM) was compared with a 9-to-20-month standard-care regimen. The primary outcome was an unfavorable status (a composite of death, treatment failure, treatment discontinuation, loss to follow-up, or recurrence of tuberculosis) at 72 weeks after randomization. The noninferiority margin was 12 percentage points.ResultsRecruitment was terminated early. Of 301 patients in stage 2 of the trial, 145, 128, and 90 patients were evaluable in the intention-to-treat, modified intention-to-treat, and per-protocol populations, respectively. In the modified intention-to-treat analysis, 11% of the patients in the BPaLM group and 48% of those in the standard-care group had a primary-outcome event (risk difference, −37 percentage points; 96.6% confidence interval [CI], −53 to −22). In the per-protocol analysis, 4% of the patients in the BPaLM group and 12% of those in the standard-care group had a primary-outcome event (risk difference, −9 percentage points; 96.6% CI, −22 to 4). In the as-treated population, the incidence of adverse events of grade 3 or higher or serious adverse events was lower in the BPaLM group than in the standard-care group (19% vs. 59%).ConclusionsIn patients with rifampin-resistant pulmonary tuberculosis, a 24-week, all-oral regimen was noninferior to the accepted standard-care treatment, and it had a better safety profile. (Funded by Médecins sans Frontières; TB-PRACTECAL ClinicalTrials.gov number, NCT02589782.)

Bedaquiline–Pretomanid–Linezolid Regimens for Drug-Resistant Tuberculosis

BackgroundThe bedaquiline–pretomanid–linezolid regimen has been reported to have 90% efficacy against highly drug-resistant tuberculosis, but the incidence of adverse events with 1200 mg of linezolid daily has been high. The appropriate dose of linezolid and duration of treatment with this agent to minimize toxic effects while maintaining efficacy against highly drug-resistant tuberculosis are unclear.MethodsWe enrolled participants with extensively drug-resistant (XDR) tuberculosis (i.e., resistant to rifampin, a fluoroquinolone, and an aminoglycoside), pre-XDR tuberculosis (i.e., resistant to rifampin and to either a fluoroquinolone or an aminoglycoside), or rifampin-resistant tuberculosis that was not responsive to treatment or for which a second-line regimen had been discontinued because of side effects. We randomly assigned the participants to receive bedaquiline for 26 weeks (200 mg daily for 8 weeks, then 100 mg daily for 18 weeks), pretomanid (200 mg daily for 26 weeks), and daily linezolid at a dose of 1200 mg for 26 weeks or 9 weeks or 600 mg for 26 weeks or 9 weeks. The primary end point in the modified intention-to-treat population was the incidence of an unfavorable outcome, defined as treatment failure or disease relapse (clinical or bacteriologic) at 26 weeks after completion of treatment. Safety was also evaluated.ResultsA total of 181 participants were enrolled, 88% of whom had XDR or pre-XDR tuberculosis. Among participants who received bedaquiline–pretomanid–linezolid with linezolid at a dose of 1200 mg for 26 weeks or 9 weeks or 600 mg for 26 weeks or 9 weeks, 93%, 89%, 91%, and 84%, respectively, had a favorable outcome; peripheral neuropathy occurred in 38%, 24%, 24%, and 13%, respectively; myelosuppression occurred in 22%, 15%, 2%, and 7%, respectively; and the linezolid dose was modified (i.e., interrupted, reduced, or discontinued) in 51%, 30%, 13%, and 13%, respectively. Optic neuropathy developed in 4 participants (9%) who had received linezolid at a dose of 1200 mg for 26 weeks; all the cases resolved. Six of the seven unfavorable microbiologic outcomes through 78 weeks of follow-up occurred in participants assigned to the 9-week linezolid groups.ConclusionsA total of 84 to 93% of the participants across all four bedaquiline–pretomanid–linezolid treatment groups had a favorable outcome. The overall risk–benefit ratio favored the group that received the three-drug regimen with linezolid at a dose of 600 mg for 26 weeks, with a lower incidence of adverse events reported and fewer linezolid dose modifications. (Funded by the TB Alliance and others; ZeNix ClinicalTrials.gov number, NCT03086486.)

Pharmacokinetic-Pharmacodynamic Determinants of Clinical Outcomes for Rifampin-Resistant Tuberculosis: A Multisite Prospective Cohort Study.

Rifampin-resistant and/or multidrug-resistant tuberculosis (RR/MDR-TB) treatment requires multiple drugs, and outcomes remain suboptimal. Some drugs are associated with improved outcome. It is unknown whether particular pharmacokinetic-pharmacodynamic relationships predict outcome. Adults with pulmonary RR/MDR-TB in Tanzania, Bangladesh, and the Russian Federation receiving local regimens were enrolled from June 2016 to July 2018. Serum was collected after 2, 4, and 8 weeks for each drug's area under the concentration-time curve over 24 hours (AUC0-24). Quantitative susceptibility of the M. tuberculosis isolate was measured by minimum inhibitory concentrations (MICs). Individual drug AUC0-24/MIC targets were assessed by adjusted odds ratios (ORs) for favorable treatment outcome, and hazard ratios (HRs) for time to sputum culture conversion. K-means clustering algorithm separated the cohort of the most common multidrug regimen into 4 clusters by AUC0-24/MIC exposures. Among 290 patients, 62 (21%) experienced treatment failure, including 30 deaths. Moxifloxacin AUC0-24/MIC target of 58 was associated with favorable treatment outcome (OR, 3.75; 95% confidence interval, 1.21-11.56; P = .022); levofloxacin AUC0-24/MIC of 118.3, clofazimine AUC0-24/MIC of 50.5, and pyrazinamide AUC0-24 of 379 mg × h/L were associated with faster culture conversion (HR >1.0, P < .05). Other individual drug exposures were not predictive. Clustering by AUC0-24/MIC revealed that those with the lowest multidrug exposures had the slowest culture conversion. Amidst multidrug regimens for RR/MDR-TB, serum pharmacokinetics and M. tuberculosis MICs were variable, yet defined parameters to certain drugs-fluoroquinolones, pyrazinamide, clofazimine-were predictive and should be optimized to improve clinical outcome. NCT03559582.

High Prevalence of Tuberculosis Infection and Disease in Child Household Contacts of Adults With Rifampin-resistant Tuberculosis.

Household contact (HHC) investigation is an important strategy to identify individuals with tuberculosis (TB) exposure, infection and disease, including those who may benefit from tuberculosis preventive therapy (TPT). Data in children exposed to rifampin-resistant TB are limited. In preparation for and to inform the feasibility of an interventional trial, HHC of adults with pulmonary rifampin-resistant TB from high TB-burden countries were evaluated in a cross-sectional study. Using interferon-gamma release assay and study-specific and 2015 international consensus definitions of intrathoracic TB in children, we evaluated the prevalence and predictors of TB infection and disease in child (<15 years) HHCs. Of 303 child HHCs, median age (range) 7 years (0-14), 57% [95% confidence interval (CI): 50%-64%] had a positive interferon-gamma release assay result (TB infected). TB infection was associated with the index case smoking (P = 0.034), being the parent or sleeping in the same room (P = 0.002) and the child HHC being age ≥5 years and having attended school (P = 0.013). Four had study-defined confirmed TB and 9 had probable TB, a prevalence of 4.3% (95% CI: 2.6%-7.1%). Using the international consensus definitions, 4 had confirmed TB and 49 had unconfirmed TB, a prevalence of 17.2% (95% CI: 12.9%-22.4%). Twenty (7%) children had received TPT. The prevalence of TB infection and disease was high in child HHC exposed to rifampin-resistant TB. Few children had routinely received TPT. High-quality evidence is needed to inform strong recommendations for and access to TPT in children exposed to TB resistant to rifampin.

DETECTION OF FLUOROQUINOLONE RESISTANCE IN MYCOBACTERIUM TUBERCULOSIS ISOLATE CAUSED BY MUTATION IN THE GYRA GENE

Drug-resistant tuberculosis is a public health concern. TB that is drug-resistant to rifampin and isoniazid is known as MDR-TB, whereas XDR-TB is MDR-TB that is also resistant to second-line medicines, such as fluoroquinolones (levofloxacin, ofloxacin, and moxifloxacin). rifampin-resistant tuberculosis (RR-TB), of which 78 percent had multidrug-resistant tuberculosis (MDR-TB) (MDR-TB). Fluoroquinolones are a class of broad-spectrum antimicrobials that have become increasingly popular in recent years. Fluoroquinolones have activity against Mycobacterium tuberculosis both in vitro and in vivo. Fluoroquinolones might cause resistance if they are used inappropriately or excessively. According to several investigations, the majority of fluoroquinolone-resistant M. tuberculosis isolates (approximately 50-90 percent) had mutations in the gyrA gene QRDR Quinolone Resistance Determination Region. However, the genetic involvement of various gyrA gene mutations in resistant Mycobacterium TB isolates against fluoroquinolone resistance remains an unknown gyrA gene mutation pattern in resistant Mycobacterium tuberculosis isolates. In the previous investigation, mutations in the gyrA gene were discovered at codons 90 and 94.

Surface-enhanced Raman spectroscopy of polymerase chain reaction (PCR) products of Rifampin resistant and susceptible tuberculosis patients

BackgroundRaman spectroscopy is an effective tool for detecting and discriminating microorganisms that is robust, reliable, and rapid. ObjectivesTo develop a polymerase chain reaction technique (PCR) based on Surface Enhanced Raman Spectroscopy (SERS) technique with principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) were used to assess diagnostic capability of SERS for distinguishing between tuberculosis (TB) positive rifampin resistant and tuberculosis (TB) positive rifampin susceptible samples. MethodsSilver nanoparticles (Ag NPs) were used as SERS substrates and technique was used to distinguish TB positive rifampin (RIF) resistant and TB positive rifampin (RIF) susceptible patients on the basis of characteristic SERS spectral features of their respective PCR products. SERS spectra were acquired from 52 samples of PCR products including 22 samples of TB positive rifampin susceptible, 30 samples of TB positive rifampin resistant and negative control samples. All these samples were collected from individuals of same age. Furthermore, multivariate data analyses techniques such as PCA and PLS-DA were used to assess diagnostic capability of SERS for distinguishing between TB positive rifampin resistant and TB positive rifampin susceptible samples. ResultsPCA is found helpful for successful differentiation among these two groups of spectral data sets. Moreover, PLS-DA provides this classification quantitatively by predicting the class of SERS spectral data set with 73% area under curve, 96% sensitivity, 95.6% specificity and 95% accuracy. ConclusionSERS can be employed for the rapid distinguishing between TB positive rifampin resistant and TB positive rifampin susceptible samples.