Highly successful treatment outcome of multidrug-resistant tuberculosis in the Netherlands, 2000-2009

Development and Validation of a Nomogram for the Prediction of Unfavorable Treatment Outcome Among Multi-Drug Resistant Tuberculosis Patients in North West Ethiopia: An Application of Prediction Modelling

Background

Multidrug-resistant tuberculosis (MDR-TB) is a global problem and a health security threat, which makes “Ending the global TB epidemic in 2035” unachievable. Globally, the unfavourable treatment outcome remains unacceptably high. Therefore, this study aimed to develop a risk prediction model for unfavorable treatment outcomes in MDR-TB patients, which can be used by clinicians as a simple clinical tool in their decision-making.

Objective

The objective of this study was to develop and validate a risk prediction model for the prediction of unfavorable treatment outcomes among MDR-TB patients in North-West Ethiopia.

Methods

We used MDR-TB data collected from the University of Gondar and Debre Markos referral hospitals. A retrospective follow-up study was conducted and a total of 517 patients were included in the study. STATA version 16 statistical software and R version 4.0.5 were used for the analysis. Descriptive statistics were carried out. A multivariable model was fitted using all potent predictors selected by the lasso regression method. A simplified risk prediction model (nomogram) was developed based on the binomial logit-based model, and its performance was described by assessing its discriminatory power and calibration. Finally, decision curve analysis (DCA) was done to evaluate the clinical and public health impact of the developed model.

Results

The developed nomogram comprised six predictors: baseline anemia, major adverse event, comorbidity, age, marital status, and treatment supporter. The model has a discriminatory power of 0.753 (95% CI: 0.708, 0.798) and calibration test of (P-value = 0.695). It was internally validated by bootstrapping method, and it has a relatively corrected discrimination performance (AUC = 0.744, 95CI: 0.699, 0.788). The optimism coefficient was found to be 0.009. The decision curve analysis showed the net benefit of the model as threshold probabilities varied.

Conclusion

The developed nomogram can be used for individualized prediction of unfavorable treatment outcomes in MDR-TB patients for it has a satisfactory level of accuracy and good calibration. The model is clinically interpretable and was found to have added benefits in clinical practice.

Treatment outcomes of patients with MDR-TB in Nepal on a current programmatic standardised regimen: retrospective single-centre study

Objectives

The objectives of this study were to evaluate treatment in patients on current programmatic multidrug-resistant tuberculosis (MDR-TB) regimen and verify eligibility for the 9-month regimen and therapeutic drug monitoring (TDM).

Methods

We performed a retrospective chart review of patients with MDR-TB receiving standardised regimen at the German Nepal TB Project Clinic, Nepal, between 2014 and 2016. Eligibility for the 9-month regimen and indications for TDM were evaluated.

Results

Out of 107 available patients’ medical records, 98 were included. In this centre, the MDR-TB treatment success rates were 69.0% in 2015, 86.6% in 2016 and 86.5% in 2017. The median time to sputum smear conversion was 60 days (60–90 IQR) and culture conversion was 60 days (60–90 IQR). Observed side effects did not impact treatment outcomes. No difference in treatment success rates was observed between patients with predisposing risk factors and those without. Only 49% (36/74) of patients were eligible for the 9-month regimen and 23 patients for TDM according to American Thoracic Society guideline criteria.

Conclusions

Nepalese patients with MDR-TB on ambulatory care had good treatment outcome after programmatic treatment. Implementation of the new WHO oral MDR-TB treatment regimen may further improve treatment results. The 9-month regimen and TDM should be considered as part of programmatic care.

Time to sputum culture conversion and its predictors among patients with multidrug-resistant tuberculosis in Hangzhou, China: A retrospective cohort study

The objective is to investigate the time to initial sputum culture conversion (SCC) and its predictors among multidrug-resistant tuberculosis (MDR-TB) patients in Hangzhou, China.A retrospective cohort study was conducted among patients who initiated MDR-TB treatment from 2011 to 2015 in Hangzhou, China. Successful achievement of initial SCC was defined as 2 consecutive negative cultures taken at least 30 days apart after initiation of treatment of MDR-TB. Successful treatment outcomes included being cured and completing treatment, while poor treatment outcomes included treatment failure, loss to follow-up, and death. Time to initial SCC was analyzed using the Kaplan-Meier method, and Cox proportional hazards regression was used to identify predictors of SCC.Among 384 patients enrolled with MDR-TB, 359 (93.5%) successfully achieved initial SCC after a median of 85 days (interquartile range, 40-112 days). A higher rate of SCC was observed in participants with successful treatment outcomes than those with poor treatment outcomes (P<.01). Multivariate analysis showed that age 25 to 64 years (compared with age<25; adjusted odds ratio [AOR], 0.7; 95% confidence interval [CI], 0.5-0.9; P < .01), age ≥65 years (compared with age < 25; AOR, 0.5; 95% CI, 0.3-0.8; P < .01), and household registration in Hangzhou (compared with non-Hangzhou registration; AOR, 1.3; 95% CI, 1.0-1.5; P < .05) were found to be associated with SCC.Although high SCC and treatment success rates were observed among MDR-TB patients in Hangzhou, the prolonged duration to initial SCC underscores the importance of emphasizing measures for infection control. A new policy of shifting outpatient treatment to inpatient treatment in China may reduce the risk of transmission from patients in the time window prior to SCC.

Development and validation of a simple LC-MS/MS method for simultaneous determination of moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol in human plasma

Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging due to high treatment failure rate and adverse drug events. This study aimed to develop and validate a simple LC-MS/MS method for simultaneous measurement of five TB drugs in human plasma and to facilitate therapeutic drug monitoring (TDM) in MDR-TB treatment to increase efficacy and reduce toxicity. Moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol were prepared in blank plasma from healthy volunteers and extracted using protein precipitation reagent containing trichloroacetic acid. Separation was achieved on an Atlantis T3 column with gradient of 0.1% formic acid in water and acetonitrile. Drug concentrations were determined by dynamic multiple reaction monitoring in positive ion mode on a LC-MS/MS system. The method was validated according to the United States' Food and Drug Administration (FDA) guideline for bioanalytical method validation. The calibration curves for moxifloxacin, levofloxacin, prothionamide, pyrazinamide and ethambutol were linear, with the correlation coefficient values above 0.993, over a range of 0.1-5, 0.4-40, 0.2-10, 2-100 and 0.2-10 mg/L, respectively. Validation showed the method to be accurate and precise with bias from 6.5% to 18.3% for lower limit of quantification and -5.8% to 14.6% for LOW, medium (MED) and HIGH drug levels, and with coefficient of variations within 11.4% for all levels. Regarding dilution integrity, the bias was within 7.2% and the coefficient of variation was within 14.9%. Matrix effect (95.7%-112.5%) and recovery (91.4%-109.7%) for all drugs could be well compensated by their isotope-labelled internal standards. A benchtop stability test showed that the degradation of prothionamide was over 15% after placement at room temperature for 72 h. Clinical samples (n = 224) from a cohort study were analyzed and all concentrations were within the analytical range. The signal of prothionamide was suppressed in samples with hemolysis which was solved by sample dilution. As the method is robust and sample preparation is simple, it can easily be implemented to facilitate TDM in programmatic MDR-TB treatment.

Treatment outcomes of multidrug-resistant tuberculosis in Hangzhou, China, 2011 to 2015

Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging. More research is needed to understand treatment outcomes and associated factors.A retrospective cohort study was conducted to assess trends and predictors of treatment success among 398 MDR-TB and extensively drug resistant TB patients who started treatment in 2011 to 2015 in Hangzhou, China. Sociodemographic and clinical characteristic data were obtained from the national reporting database. Chi-square test for trend was used to evaluate changes in treatment success rates over the study years, and Cox regression analysis was used to identify predictors for poor treatment outcomes.The treatment success rate was 76% (301/398) for all participants, 77% (298/387) for MDR-TB cases and 27% (3/11) for extensively drug-resistant tuberculosis -TB cases. Treatment success increased significantly from 66% among patients who started treatment in 2011 to 85% in 2015 (P < .01). Of the 97 (24.4%) patients with unsuccessful treatment outcomes, 10 (2.5%) died, 64 (16.1%) failed treatment, and 23 (5.8%) were lost to follow-up. Patients who started treatment in 2013 to 2015 were less likely to have unsuccessful outcomes than those who started in 2011-2012 (adjusted odds ratio [AOR] 0.4, 95% confidence interval [CI] 0.3-0.6), patients ≥25 years were more likely to have unsuccessful outcomes than younger patients (AOR 1.6, 95% CI 1.3-2.1), and cases with kanamycin resistance was associated with three times the odds of having unsuccessful outcomes than kanamycin-susceptible cases (AOR 3.0, 95% CI 1.5-5.8).With proper case management of MDR-TB, patients can achieve a high treatment success rate. Hangzhou's program offers clinical evidence that can be used to inform MDR-TB programs elsewhere in China and abroad.

Prospective evaluation of improving fluoroquinolone exposure using centralised therapeutic drug monitoring (TDM) in patients with tuberculosis (PERFECT): a study protocol of a prospective multicentre cohort study

INTRODUCTION

Global multidrug-resistant tuberculosis (MDR-TB) treatment success rates remain suboptimal. Highly active WHO group A drugs moxifloxacin and levofloxacin show intraindividual and interindividual pharmacokinetic variability which can cause low drug exposure. Therefore, therapeutic drug monitoring (TDM) of fluoroquinolones is recommended to personalise the drug dosage, aiming to prevent the development of drug resistance and optimise treatment. However, TDM is considered laborious and expensive, and the clinical benefit in MDR-TB has not been extensively studied. This observational multicentre study aims to determine the feasibility of centralised TDM and to investigate the impact of fluoroquinolone TDM on sputum conversion rates in patients with MDR-TB compared with historical controls.

METHODS AND ANALYSIS

Patients aged 18 years or older with sputum smear and culture-positive pulmonary MDR-TB will be eligible for inclusion. Patients receiving TDM using a limited sampling strategy (t=0 and t=5 hours) will be matched to historical controls without TDM in a 1:2 ratio. Sample analysis and dosing advice will be performed in a centralised laboratory. Centralised TDM will be considered feasible if >80% of the dosing recommendations are returned within 7 days after sampling and 100% within 14 days. The number of patients who are sputum smear and culture-negative after 2 months of treatment will be determined in the prospective TDM group and will be compared with the control group without TDM to determine the impact of TDM.

ETHICS AND DISSEMINATION

Ethical clearance was obtained by the ethical review committees of the 10 participating hospitals according to local procedures or is pending (online supplementary file 1). Patients will be included after obtaining written informed consent. We aim to publish the study results in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Registry (NCT03409315).

Drug-associated adverse events in the treatment of multidrug-resistant tuberculosis: an individual patient data meta-analysis

BACKGROUND

Treatment of multidrug-resistant tuberculosis requires long-term therapy with a combination of multiple second-line drugs. These drugs are associated with numerous adverse events that can cause severe morbidity, such as deafness, and in some instances can lead to death. Our aim was to estimate the absolute and relative frequency of adverse events associated with different tuberculosis drugs to provide useful information for clinicians and tuberculosis programmes in selecting optimal treatment regimens.

METHODS

We did a meta-analysis using individual-level patient data that were obtained from studies that reported adverse events that resulted in permanent discontinuation of anti-tuberculosis medications. We used a database created for our previous meta-analysis of multidrug-resistant tuberculosis treatment and outcomes, for which we did a systematic review of literature published between Jan 1, 2009, and Aug 31, 2015 (updated April 15, 2016), and requested individual patient-level information from authors. We also considered for this analysis studies contributing patient-level data in response to a public call made by WHO in 2018. Meta-analysis for proportions and arm-based network meta-analysis were done to estimate the incidence of adverse events for each tuberculosis drug.

FINDINGS

58 studies were identified, including 50 studies from the updated individual patient data meta-analysis for multidrug-resistant tuberculosis treatment. 35 of these studies, with 9178 patients, were included in our analysis. Using meta-analysis of proportions, drugs with low risks of adverse event occurrence leading to permanent discontinuation included levofloxacin (1·3% [95% CI 0·3-5·0]), moxifloxacin (2·9% [1·6-5·0]), bedaquiline (1·7% [0·7-4·2]), and clofazimine (1·6% [0·5-5·3]). Relatively high incidence of adverse events leading to permanent discontinuation was seen with three second-line injectable drugs (amikacin: 10·2% [6·3-16·0]; kanamycin: 7·5% [4·6-11·9]; capreomycin: 8·2% [6·3-10·7]), aminosalicylic acid (11·6% [7·1-18·3]), and linezolid (14·1% [9·9-19·6]). Risk of bias in selection of studies was judged to be low because there were no important differences between included and excluded studies. Variability between studies was significant for most outcomes analysed.

INTERPRETATION

Fluoroquinolones, clofazimine, and bedaquiline had the lowest incidence of adverse events leading to permanent drug discontinuation, whereas second-line injectable drugs, aminosalicylic acid, and linezolid had the highest incidence. These results suggest that close monitoring of adverse events is important for patients being treated for multidrug-resistant tuberculosis. Our results also underscore the urgent need for safer and better-tolerated drugs to reduce morbidity from treatment itself for patients with multidrug-resistant tuberculosis.

FUNDING

Canadian Institutes of Health Research, Centers for Disease Control and Prevention (USA), American Thoracic Society, European Respiratory Society, and Infectious Diseases Society of America.

Standardised shorter regimens versus individualised longer regimens for rifampin- or multidrug-resistant tuberculosis

We sought to compare the effectiveness of two World Health Organization (WHO)-recommended regimens for the treatment of rifampin- or multidrug-resistant (RR/MDR) tuberculosis (TB): a standardised regimen of 9-12 months (the "shorter regimen") and individualised regimens of ≥20 months ("longer regimens").We collected individual patient data from observational studies identified through systematic reviews and a public call for data. We included patients meeting WHO eligibility criteria for the shorter regimen: not previously treated with second-line drugs, and with fluoroquinolone- and second-line injectable agent-susceptible RR/MDR-TB. We used propensity score matched, mixed effects meta-regression to calculate adjusted odds ratios and adjusted risk differences (aRDs) for failure or relapse, death within 12 months of treatment initiation and loss to follow-up.We included 2625 out of 3378 (77.7%) individuals from nine studies of shorter regimens and 2717 out of 13 104 (20.7%) individuals from 53 studies of longer regimens. Treatment success was higher with the shorter regimen than with longer regimens (pooled proportions 80.0% versus 75.3%), due to less loss to follow-up with the former (aRD -0.15, 95% CI -0.17- -0.12). The risk difference for failure or relapse was slightly higher with the shorter regimen overall (aRD 0.02, 95% CI 0-0.05) and greater in magnitude with baseline resistance to pyrazinamide (aRD 0.12, 95% CI 0.07-0.16), prothionamide/ethionamide (aRD 0.07, 95% CI -0.01-0.16) or ethambutol (aRD 0.09, 95% CI 0.04-0.13).In patients meeting WHO criteria for its use, the standardised shorter regimen was associated with substantially less loss to follow-up during treatment compared with individualised longer regimens and with more failure or relapse in the presence of resistance to component medications. Our findings support the need to improve access to reliable drug susceptibility testing.

Risk factors for poor treatment outcomes of 2266 multidrug-resistant tuberculosis cases in Ho Chi Minh City: a retrospective study

BACKGROUND

Multidrug resistant tuberculosis (MDR-TB) remains a serious public health problem with poor treatment outcomes. Predictors of poor outcomes vary in different regions. Vietnam is among the top 30 high burden of MDR-TB countries. We describe demographic characteristics and identify risk factors for poor outcome among patients with MDR-TB in Ho Chi Minh City (HCMC), the most populous city in Vietnam.

METHODS

This retrospective study included 2266 patients who initiated MDR-TB treatment between 2011 and 2015 in HCMC. Treatment outcomes were available for 2240 patients. Data was collected from standardized paper-based treatment cards and electronic records. A Kruskal Wallis test was used to assess changes in median age and body mass index (BMI) over time, and a Wilcoxon test was used to compare the median BMI of patients with and without diabetes mellitus. Chi squared test was used to compare categorical variables. Multivariate logistic regression with multiple imputation for missing data was used to identify risk factors for poor outcomes. Statistical analysis was performed using R program.

RESULTS

Among 2266 eligible cases, 60.2% had failed on a category I or II treatment regimen, 57.7% were underweight, 30.2% had diabetes mellitus and 9.6% were HIV positive. The notification rate increased 24.7% from 2011 to 2015. The treatment success rate was 73.3%. Risk factors for poor treatment outcome included HIV co-infection (adjusted odds ratio (aOR): 2.94), advanced age (aOR: 1.45 for every increase of 5 years for patients 60 years or older), having history of MDR-TB treatment (aOR: 5.53), sputum smear grade scanty or 1+ (aOR: 1.47), smear grade 2+ or 3+ (aOR: 2.06), low BMI (aOR: 0.83 for every increase of 1 kg/m2 of BMI for patients with BMI < 21).

CONCLUSION

The number of patients diagnosed with MDR-TB in HCMC increased by almost a quarter between 2011 and 2015. Patients with HIV, high smear grade, malnutrition or a history of previous MDR-TB treatment are at greatest risk of poor treatment outcome.

Reduced susceptibility and resistance to bedaquiline in clinical M. tuberculosis isolates

OBJECTIVES

Bedaquiline is an effective drug used to treat MDR and XDR tuberculosis, providing high cure rates in complex therapy. Mutations in the mmpR (rv0678) and atpE genes are associated with reduced susceptibility to bedaquiline and have been identified in both in vitro selected strains and clinical isolates. However, the phenotypic criteria used to detect bedaquiline resistance have yet to be established due to the collection of few clinical isolates from patients receiving bedaquiline-containing treatment regimens.

METHODS

One hundred eighty-two clinical isolates from 74 patients receiving bedaquiline and 163 isolates from 107 patients not exposed to bedaquiline were analysed. The bedaquiline MICs were tested using serial dilutions on 7H11 agar plates and the Bactec MGIT 960 system. The mmpR and atpE genes were sequenced by Sanger sequencing.

RESULTS

The 7H11 agar method allowed for rapid discrimination between mutated and wild-type isolates and between exposed and non-exposed isolates. Seventy-three percent of bedaquiline-exposed isolates, as well as 91% of isolates with mutations, had an elevated bedaquiline MIC (≥ 0.12 mg/L on 7H11 media) compared to the reference isolates (89% had an MIC ≤ 0.03 mg/L). Previously reported in vitro-selected mutants (E61D and A63P) and novel AtpE substitutions (G25S and D28G) were observed in the clinical isolates. Substitutions in codon 63 of AtpE were likely associated with a higher bedaquiline MIC. Five new cases of pre-existing reduced susceptibility to bedaquiline, accompanied by mmpR mutations in most isolates, without a history of bedaquiline treatment were identified.

CONCLUSIONS

Bedaquiline treatment leads to an elevated bedaquiline MIC and the acquisition of mmpR and atpE gene mutations in tuberculosis strains. The standardisation of bedaquiline phenotypic susceptibility testing is urgently needed based on observed discrepancies between our study and previous studies and differences in solid and liquid media MIC determinations.

Factors predictive of the success of tuberculosis treatment: A systematic review with meta-analysis

OBJECTIVE

To produce pooled estimates of the global results of tuberculosis (TB) treatment and analyze the predictive factors of successful TB treatment.

METHODS

Studies published between 2014 and 2019 that reported the results of the treatment of pulmonary TB and the factors that influenced these results. The quality of the studies was evaluated according to the Newcastle-Ottawa quality assessment scale. A random effects model was used to calculate the pooled odds ratio (OR) and 95% confidence interval (CI). This review was registered in the International Prospective Register of Systematic Reviews (PROSPERO) in February 2019 under number CRD42019121512.

RESULTS

A total of 151 studies met the criteria for inclusion in this review. The success rate for the treatment of drug-sensitive TB in adults was 80.1% (95% CI: 78.4-81.7). America had the lowest treatment success rate, 75.9% (95% CI: 73.8-77.9), and Oceania had the highest, 83.9% (95% CI: 75.2-91.0). In children, the success rate was 84.8% (95% CI: 77.7-90.7); in patients coinfected with HIV, it was 71.0% (95% CI: 63.7-77.8), in patients with multidrug-resistant TB, it was 58.4% (95% CI: 51.4-64.6), in patients with and extensively drug-resistant TB it was 27.1% (12.7-44.5). Patients with negative sputum smears two months after treatment were almost three times more likely to be successfully treated (OR 2.7; 1.5-4.8), whereas patients younger than 65 years (OR 2.0; 1.7-2.4), nondrinkers (OR 2.0; 1.6-2.4) and HIV-negative patients (OR 1.9; 1.6-2.5 3) were two times more likely to be successfully treated.

CONCLUSION

The success of TB treatment at the global level was good, but was still below the defined threshold of 85%. Factors such as age, sex, alcohol consumption, smoking, lack of sputum conversion at two months of treatment and HIV affected the success of TB treatment.

Whole genome sequencing for drug-resistant tuberculosis management in South Africa: What gaps would this address and what are the challenges to implementation?

Global control of tuberculosis (TB) has been seriously impacted by the emergence and transmission of its drug-resistant forms. Delayed detection and incomplete characterisation of drug-resistant tuberculosis (DR-TB) contributes to morbidity and mortality, and to ongoing transmission of drug-resistant strains. Current culture-based and molecular diagnostic tools for TB present numerous disadvantages that could potentially lead to misdiagnosis, inappropriate treatment initiation and the amplification of drug resistance. The detection of drug-resistant tuberculosis (DR-TB) in South Africa relies on molecular diagnostic assays such as the Xpert MTB/RIF and line probe assays (MTBDRplus and MTBDRsl). However, these molecular assays are limited to detecting resistance to only a few first-line and second-line drugs. It is for this reason that next-generation sequencing (NGS) and bioinformatics pipelines have been developed for rapid detection of M. tuberculosis drug resistance, with the added advantage that sequence data could also have public health applications through understanding transmission patterns. This review highlights some of the challenges that are currently hampering the diagnosis and control of DR-TB in a high burden setting of the KwaZulu-Natal (KZN) province in South Africa. Shortfalls of current diagnostic techniques for DR-TB are discussed in detail and we also propose how these might be overcome with an accurate and rapid NGS system.

Treatment Outcomes of Multidrug-Resistant Tuberculosis in Taiwan: Tackling Loss to Follow-up

Background

The proportion of treatment success among patients with multidrug-resistant tuberculosis (MDR-TB) enrolled between 1992 and 1996 was 51.2%, and that among patients enrolled between 2000 and April 2007 was 61%. To address the challenge of MDR-TB, the Taiwan MDR-TB Consortium (TMTC) was established in May 2007. To assess the performance of the TMTC, we analyzed the data of patients enrolled in its first 5 years.

Methods

Comprehensive care was provided at no cost to patients, who were usually hospitalized for 1 month initially. Treatment regimens consisted of 4–5 drugs and the duration of treatment was 18–24 months. A case manager and a directly observed therapy provider were assigned to each patient. Psychosocial support was provided to address emotional stress and stigma. Financial support was offered to avoid the financial hardship faced by patients and their families. We assessed treatment outcomes at 30 months using internationally recommended outcome definitions.

Results

Of the 692 MDR-TB patients, 570 (82.4%) were successfully treated, 84 (12.1%) died, 18 (2.6%) had treatment failure, and 20 (2.9%) were lost to follow-up. Age ≥65 years (adjusted odds ratio [aOR], 6.78 [95% confidence interval {CI}, 3.14–14.63]), cancer (aOR, 11.82 [95% CI, 5.55–25.18]), and chronic kidney disease (aOR, 3.62 [95% CI, 1.70–7.71]) were significantly associated with death. Resistance to fluoroquinolone (aOR, 10.89 [95% CI, 3.97–29.88]) was significantly associated with treatment failure.

Conclusions

The TMTC, which operates under a strong collaboration between the public health authority and clinical teams, has been a highly effective model of care in the management of MDR-TB.

Clinical Management of Multidrug-Resistant Tuberculosis in 16 European Countries

RATIONALE

Multidrug-resistant tuberculosis (MDR-TB) is a major burden to public health in Europe. Reported treatment success rates are around 50% or less, and cure rates are even lower.

OBJECTIVES

To document the management and treatment outcome in patients with MDR-TB in Europe.

METHODS

We performed a prospective cohort study, analyzing management and treatment outcomes stratified by incidence of patients with MDR-TB in Europe. Treatment outcomes were compared by World Health Organization and alternative simplified definitions by the Tuberculosis Network European Trialsgroup (TBNET).

MEASUREMENTS AND MAIN RESULTS

A total of 380 patients with MDR-TB were recruited and followed up between 2010 and 2014 in 16 European countries. Patients in high-incidence countries compared with low-incidence countries were treated more frequently with standardized regimen (83.2% vs. 9.9%), had delayed treatment initiation (median, 111 vs. 28 d), developed more additional drug resistance (23% vs. 5.8%), and had increased mortality (9.4% vs. 1.9%). Only 20.1% of patients using pyrazinamide had proven susceptibility to the drug. Applying World Health Organization outcome definitions, frequency of cure (38.7% vs. 9.7%) was higher in high-incidence countries. Simplified outcome definitions that include 1 year of follow-up after the end of treatment showed similar frequency of relapse-free cure in low- (58.3%), intermediate- (55.8%), and high-incidence (57.1%) countries, but highest frequency of failure in high-incidence countries (24.1% vs. 14.6%).

CONCLUSIONS

Conventional standard MDR-TB treatment regimens resulted in a higher frequency of failure compared with individualized treatments. Overall, cure from MDR-TB is substantially more frequent than previously anticipated, and poorly reflected by World Health Organization outcome definitions.

Treatment outcomes of drug-resistant tuberculosis in the Netherlands, 2005-2015

Background

Since in low incidence TB countries population migration and complex treatment of drug-resistant tuberculosis (DR-TB) patients are major issues, we aimed to analyse patient risk factors associated with the incidence of poor outcome of TB treatment among DR-TB patients in the Netherlands.

Methods

This retrospective cohort study included adult patients with confirmed DR-TB treated from 2005 to 2015. We obtained data from a nationwide exhaustive registry of tuberculosis patients in the Netherlands. Predictors for unsuccessful TB treatment (defaulted and failed treatment) and TB-associated mortality were analysed using multivariate logistic regression.

Results

Among 10,303 registered TB patients, 545 patients with DR-TB were analysed. Six types of DR-TB were identified from the included patients, i.e. isoniazid mono- or poly-resistance (68%); rifampicin mono- or poly-resistance (3.1%); pyrazinamide mono-resistance (8.3%); ethambutol mono-resistance (0.1%); multidrug-resistance (18.9%); and extensively drug-resistance (0.7%). The majority of patients were foreign-born (86%) and newly diagnosed TB (89%) patients. The cumulative incidence of unsuccessful treatment and mortality were 5 and 1%, respectively. Among all DR-TB cases, patients with Multi Drug-Resistant Tuberculosis (MDR-TB) (OR 4.43; 95%CI 1.70-11.60) were more likely to have unsuccessful treatment, while miliary and central nervous system TB (OR 15.60; 95%CI 2.18-111.52) may also be predictors for TB mortality. Additionally, patients with substance abuse and homelessness tend to have unsuccessful treatment.

Conclusions

In recent years, we identified a low incidence of DR-TB as well as the poor outcome of DR-TB treatment. The majority of cases were primary drug-resistant and foreign-born. To further improve treatment outcome, special attention should be given to the high-risk DR-TB patients.

Evaluation of Saliva as a Potential Alternative Sampling Matrix for Therapeutic Drug Monitoring of Levofloxacin in Patients with Multidrug-Resistant Tuberculosis

Saliva may be a useful alternative matrix for monitoring levofloxacin concentrations in multidrug-resistant tuberculosis (MDR-TB) patients. The objectives of this study were (i) to evaluate the correlation between plasma and salivary levofloxacin (Lfx) concentrations in MDR-TB patients and (ii) to gauge the possibility of using saliva as an alternative sampling matrix for therapeutic drug monitoring of Lfx in areas where TB is endemic. This was a prospective pharmacokinetic study that enrolled MDR-TB patients receiving levofloxacin (750- to 1,000-mg once-daily dosing) under standardized treatment regimen in Nepal. Paired blood and saliva samples were collected at steady state. Lfx concentrations were quantified using liquid chromatography-tandem mass spectrometry. Pharmacokinetic parameters were calculated using noncompartmental kinetics. Lfx drug exposures were evaluated in 23 MDR-TB patients. During the first month, the median (interquartile range [IQR]) areas under the concentration-time curve from 0 to 24 h (AUC_0-24) were 67.09 (53.93 to 98.37) mg ⋅ h/liter in saliva and 99.91 (76.80 to 129.70) mg ⋅ h/liter in plasma, and the saliva plasma (S/P) ratio was 0.69 (0.53 to 0.99). Similarly, during the second month, the median (IQR) AUC_0-24 were 75.63 (61.45 to 125.5) mg ⋅ h/liter in saliva and 102.7 (84.46 to 131.9) mg ⋅ h/liter in plasma, with an S/P ratio of 0.73 (0.66 to 1.18). Furthermore, large inter- and intraindividual variabilities in Lfx concentrations were observed. This study could not demonstrate a strong correlation between plasma and saliva Lfx levels. Despite a good Lfx penetration in saliva, the variability in individual saliva-to-plasma ratios limits the use of saliva as a valid substitute for plasma. Nevertheless, saliva could be useful in semiquantitatively predicting Lfx plasma levels. (This study has been registered at ClinicalTrials.gov under identifier NCT03000517.).

Linezolid for drug-resistant pulmonary tuberculosis

BACKGROUND

Linezolid was recently re-classified as a Group A drug by the World Health Organization (WHO) for treatment of multi-drug resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), suggesting that it should be included in the regimen for all patients unless contraindicated. Linezolid use carries a considerable risk of toxicity, with the optimal dose and duration remaining unclear. Current guidelines are mainly based on evidence from observational non-comparative studies.

OBJECTIVES

To assess the efficacy of linezolid when used as part of a second-line regimen for treating people with MDR and XDR pulmonary tuberculosis, and to assess the prevalence and severity of adverse events associated with linezolid use in this patient group.

SEARCH METHODS

We searched the following databases: the Cochrane Infectious Diseases Specialized Register; CENTRAL; MEDLINE; Embase; and LILACS up to 13 July 2018. We also checked article reference lists and contacted researchers in the field.

SELECTION CRITERIA

We included studies in which some participants received linezolid, and others did not. We included randomized controlled trials (RCTs) of linezolid for MDR and XDR pulmonary tuberculosis to evaluate efficacy outcomes. We added non-randomized cohort studies to evaluate adverse events.Primary outcomes were all-cause and tuberculosis-associated death, treatment failure, and cure. Secondary outcomes were treatment interrupted, treatment completed, and time to sputum culture conversion. We recorded frequency of all and serious adverse events, adverse events leading to drug discontinuation or dose reduction, and adverse events attributed to linezolid, particularly neuropathy, anaemia, and thrombocytopenia.

DATA COLLECTION AND ANALYSIS

Two review authors (BS and DC) independently assessed the search results for eligibility and extracted data from included studies. All review authors assessed risk of bias using the Cochrane 'Risk of bias' tool for RCTs and the ROBINS-I tool for non-randomized studies. We contacted study authors for clarification and additional data when necessary.We were unable to perform a meta-analysis as one of the RCTs adopted a study design where participants in the study group received linezolid immediately and participants in the control group received linezolid after two months, and therefore there were no comparable data from this trial. We deemed meta-analysis of non-randomized study data inappropriate.

MAIN RESULTS

We identified three RCTs for inclusion. One of these studies had serious problems with allocation of the study drug and placebo, so we could not analyse data for intervention effect from it. The remaining two RCTs recruited 104 participants. One randomized 65 participants to receive linezolid or not, in addition to a background regimen; the other randomized 39 participants to addition of linezolid to a background regimen immediately, or after a delay of two months. We included 14 non-randomized cohort studies (two prospective, 12 retrospective), with a total of 1678 participants.Settings varied in terms of income and tuberculosis burden. One RCT and 7 out of 14 non-randomized studies commenced recruitment in or after 2009. All RCT participants and 38.7% of non-randomized participants were reported to have XDR-TB.Dosing and duration of linezolid in studies were variable and reported inconsistently. Daily doses ranged from 300 mg to 1200 mg; some studies had planned dose reduction for all participants after a set time, others had incompletely reported dose reductions for some participants, and most did not report numbers of participants receiving each dose. Mean or median duration of linezolid therapy was longer than 90 days in eight of the 14 non-randomized cohorts that reported this information.Duration of participant follow-up varied between RCTs. Only five out of 14 non-randomized studies reported follow-up duration.Both RCTs were at low risk of reporting bias and unclear risk of selection bias. One RCT was at high risk of performance and detection bias, and low risk for attrition bias, for all outcomes. The other RCT was at low risk of detection and attrition bias for the primary outcome, with unclear risk of detection and attrition bias for non-primary outcomes, and unclear risk of performance bias for all outcomes. Overall risk of bias for the non-randomized studies was critical for three studies, and serious for the remaining 11.One RCT reported higher cure (risk ratio (RR) 2.36, 95% confidence interval (CI) 1.13 to 4.90, very low-certainty evidence), lower failure (RR 0.26, 95% CI 0.10 to 0.70, very low-certainty evidence), and higher sputum culture conversion at 24 months (RR 2.10, 95% CI 1.30 to 3.40, very low-certainty evidence), amongst the linezolid-treated group than controls, with no differences in other primary and secondary outcomes. This study also found more anaemia (17/33 versus 2/32), nausea and vomiting, and neuropathy (14/33 versus 1/32) events amongst linezolid-receiving participants. Linezolid was discontinued early and permanently in two of 33 (6.1%) participants who received it.The other RCT reported higher sputum culture conversion four months after randomization (RR 2.26, 95% CI 1.19 to 4.28), amongst the group who received linezolid immediately compared to the group who had linezolid initiation delayed by two months. Linezolid was discontinued early and permanently in seven of 39 (17.9%) participants who received it.Linezolid discontinuation occurred in 22.6% (141/624; 11 studies), of participants in the non-randomized studies. Total, serious, and linezolid-attributed adverse events could not be summarized quantitatively or comparatively, due to incompleteness of data on duration of follow-up and numbers of participants experiencing events.

AUTHORS' CONCLUSIONS

We found some evidence of efficacy of linezolid for drug-resistant pulmonary tuberculosis from RCTs in participants with XDR-TB but adverse events and discontinuation of linezolid were common. Overall, there is a lack of comparative data on efficacy and safety. Serious risk of bias and heterogeneity in conducting and reporting non-randomized studies makes the existing, mostly retrospective, data difficult to interpret. Further prospective cohort studies or RCTs in high tuberculosis burden low-income and lower-middle-income countries would be useful to inform policymakers and clinicians of the efficacy and safety of linezolid as a component of drug-resistant TB treatment regimens.

Treatment efficacy of drug-resistant tuberculosis in Bashkortostan, Russia: A retrospective cohort study

BACKGROUND

Russia, together with other former Soviet Union countries, is characterized by one of the highest burdens of drug-resistant tuberculosis. Published data on the drug-resistant tuberculosis for these countries are limited, and it is not clear whether current treatment regimens remain effective against constantly evolving drug-resistant strains.

OBJECTIVES

The aim of the study was to evaluate treatment efficacy of patients with multidrug-resistant (MDR), extensively drug-resistant (XDR) and drug-susceptible (DSTB) tuberculosis in the most populous region of Russia (Bashkortostan) that borders with Central Asia.

METHODS

A retrospective cohort study was performed on 436 patients with pulmonary tuberculosis who were enrolled between January 1, 2016, and February 28, 2018, and received treatment according to WHO recommendations. Altogether, 369 patients completed the full course of chemotherapy. Clinical characteristics and treatment outcomes of DSTB, MDR, and XDR-TB patients were analyzed.

RESULTS

Of 436 patients, 169 (39%) had XDR-TB, 94 (22%) had MDR-TB and 173 (40%) had DSTB. Half of the MDR-TB patients (44%) and 82% of XDR-TB patients failed treatment. Patients with DSTB had unexpectedly poor treatment efficacy: only 67% had treatment success. We found that most of the MDR isolates from our patients were resistant to all first-line drugs, and a majority of the XDR isolates were resistant to more than 6-7 anti-TB drugs. While this can explain poor treatment efficacy in drug-resistant cases, causes of poor treatment efficacy in DSTB patients remain unclear. Finally, a considerable fraction (46%) of newly diagnosed patients had MDR-TB (27%) and XDR-TB (19%), suggesting that drug-resistant Mtb is being transmitted in the general population. To our best knowledge, this study is the first one to report XDR-TB prevalence in Russia in recent years (2016-2018).

CONCLUSIONS

MDR and XDR-TB became more common in recent years and treatment efficacy is declining at the face of more extensive drug resistance. There is evidence for the transmission of resistant strains in the general population, which calls for urgent changes not only in clinical practice but also in measures to prevent spread in the general population.

High treatment success rate among multidrug-resistant tuberculosis patients in Myanmar, 2012-2014: a retrospective cohort study

Background

Since 2011, Myanmar has adopted domiciliary care for multidrug-resistant tuberculosis (MDR-TB) patients and implemented several patient-support measures such as community-based directly observed treatment, nutritional support and financial incentives for patients and providers. We assessed treatment outcomes among MDR-TB patients registered for treatment in the Yangon and Mandalay Regions of Myanmar during 2012-2014 and factors associated with unfavourable treatment outcomes.

Methods

We performed a retrospective cohort study involving secondary analysis of routine programmatic data extracted from the electronic MDR-TB treatment registries. We calculated the adjusted risk ratio (aRR) and 95% confidence interval (CI).

Results

Of 2185 MDR-TB patients (75% HIV tested, 14% HIV positive with 70% of them receiving antiretroviral therapy), 1746 (80%) were successfully treated (cured and treatment completed) and 20% had unfavourable outcomes (14% died, 3% lost to follow-up, 2% failure and 1% not evaluated). Compared with young patients (<25 y), patients 25-54 y of age (aRR 2.0 [95% CI 1.3 to 2.9]) and >55 y (aRR 3.2 [95% CI 2.1 to 4.8]) were more likely to have unfavourable outcomes. HIV-positive patients (especially not receiving ART; aRR 2.2 [95% CI 1.4 to 3.6]) and patients with 'unknown HIV status' (aRR 1.9 [95% CI 1.5-2.4]) had a higher risk of unfavourable outcomes compared with HIV-negative patients.

Conclusions

Treatment success was high and deaths accounted for three-fourths of unfavourable outcomes. Joint care and management of MDR-TB and HIV co-infected patients should be strengthened.

Recent developments in the diagnosis of drug-resistant tuberculosis

Urgent steps are required to control the drug-resistant tuberculosis (TB) epidemic worldwide. Individualised treatment, using detailed drug-susceptibility test results to guide choice of antibiotics, improves patient outcomes and minimises adverse effects. Recent years have seen substantial advances in our ability to provide rapid, detailed drug-resistance profiles using genotypic methods for detection of mutations conferring drug-resistance. Rapid testing using real-time PCR to target the most important drug-resistance mutations allows the diagnosis of drug resistance to be made with the first diagnostic test, even in low resource settings. The use of whole genome sequencing to infer resistance to a range of different drugs facilitates earlier tailoring of therapy and detection of resistant subpopulations in mixed infections. Low burden countries, such as Australia are well positioned to lead the development and refinement of these new methods, to accelerate the incorporation of these new tools into TB control programs in high burden countries.

Patient support for tuberculosis patients in low-incidence countries: A systematic review

Background

Patient support during tuberculosis treatment is expected to be more often available and more customized in low tuberculosis incidence, high-resource settings than in lower-resource settings. The aim of this systematic review is to provide an overview of tuberculosis patient support interventions implemented in low-incidence countries and an evaluation of their effects on treatment-related outcomes as well as their acceptability by patients and providers.

Methods

PubMed, Social Science Citation Index and Cumulative Index to Nursing and Allied Health and Literature were searched for the period 01.2006–05.2016 on publications describing tuberculosis patient support interventions in low-incidence countries (<20 patients per 100,000 population).

Results

Through our search strategy, 1875 unique publications were identified. Forty publications were included: 17 evaluated patient support quantitatively, 9 qualitatively and 14 only described the patient support. Nineteen publications assessed treatment supervision options only, 21 assessed (combinations of) treatment supervision, socio-economic, psycho-emotional, health-educational and other support. Of eight studies quantitatively evaluating the effects of support with a control group, four showed positive effects: two out of three that used combinations of patient support and two out of five that compared treatment supervision options. Heterogeneity of interventions precluded pooling of results. Qualitative and descriptive studies showed that patients appreciated individualized support including treatment supervision, psycho-emotional and socio-economic support; and digital health interventions.

Conclusion

Our review shows that a variety of patient support interventions is implemented in low-incidence countries. Although only a few interventions were evaluated quantitatively, we identified potential best practices. The scarcity of evidence on effectiveness, however, indicates the need for further research to evaluate potential best practices.

Treatment correlates of successful outcomes in pulmonary multidrug-resistant tuberculosis: an individual patient data meta-analysis

BACKGROUND

Treatment outcomes for multidrug-resistant tuberculosis remain poor. We aimed to estimate the association of treatment success and death with the use of individual drugs, and the optimal number and duration of treatment with those drugs in patients with multidrug-resistant tuberculosis.

METHODS

In this individual patient data meta-analysis, we searched MEDLINE, Embase, and the Cochrane Library to identify potentially eligible observational and experimental studies published between Jan 1, 2009, and April 30, 2016. We also searched reference lists from all systematic reviews of treatment of multidrug-resistant tuberculosis published since 2009. To be eligible, studies had to report original results, with end of treatment outcomes (treatment completion [success], failure, or relapse) in cohorts of at least 25 adults (aged >18 years). We used anonymised individual patient data from eligible studies, provided by study investigators, regarding clinical characteristics, treatment, and outcomes. Using propensity score-matched generalised mixed effects logistic, or linear regression, we calculated adjusted odds ratios and adjusted risk differences for success or death during treatment, for specific drugs currently used to treat multidrug-resistant tuberculosis, as well as the number of drugs used and treatment duration.

FINDINGS

Of 12 030 patients from 25 countries in 50 studies, 7346 (61%) had treatment success, 1017 (8%) had failure or relapse, and 1729 (14%) died. Compared with failure or relapse, treatment success was positively associated with the use of linezolid (adjusted risk difference 0·15, 95% CI 0·11 to 0·18), levofloxacin (0·15, 0·13 to 0·18), carbapenems (0·14, 0·06 to 0·21), moxifloxacin (0·11, 0·08 to 0·14), bedaquiline (0·10, 0·05 to 0·14), and clofazimine (0·06, 0·01 to 0·10). There was a significant association between reduced mortality and use of linezolid (-0·20, -0·23 to -0·16), levofloxacin (-0·06, -0·09 to -0·04), moxifloxacin (-0·07, -0·10 to -0·04), or bedaquiline (-0·14, -0·19 to -0·10). Compared with regimens without any injectable drug, amikacin provided modest benefits, but kanamycin and capreomycin were associated with worse outcomes. The remaining drugs were associated with slight or no improvements in outcomes. Treatment outcomes were significantly worse for most drugs if they were used despite in-vitro resistance. The optimal number of effective drugs seemed to be five in the initial phase, and four in the continuation phase. In these adjusted analyses, heterogeneity, based on a simulated I² method, was high for approximately half the estimates for specific drugs, although relatively low for number of drugs and durations analyses.

INTERPRETATION

Although inferences are limited by the observational nature of these data, treatment outcomes were significantly better with use of linezolid, later generation fluoroquinolones, bedaquiline, clofazimine, and carbapenems for treatment of multidrug-resistant tuberculosis. These findings emphasise the need for trials to ascertain the optimal combination and duration of these drugs for treatment of this condition.

FUNDING

American Thoracic Society, Canadian Institutes of Health Research, US Centers for Disease Control and Prevention, European Respiratory Society, Infectious Diseases Society of America.

Drug-resistant tuberculosis: An update on disease burden, diagnosis and treatment

The emergence of antimicrobial resistance against Mycobacterium tuberculosis, the leading cause of mortality due to a single microbial pathogen worldwide, represents a growing threat to public health and economic growth. The global burden of multidrug-resistant tuberculosis (MDR-TB) has recently increased by an annual rate of more than 20%. According to the World Health Organization approximately only half of all patients treated for MDR-TB achieved a successful outcome. For many years, patients with drug-resistant tuberculosis (TB) have received standardized treatment regimens, thereby accelerating the development of MDR-TB through drug-specific resistance amplification. Comprehensive drug susceptibility testing (phenotypic and/or genotypic) is necessary to inform physicians about the best drugs to treat individual patients with tailor-made treatment regimens. Phenotypic drug resistance can now often, but with variable sensitivity, be predicted by molecular drug susceptibility testing based on whole genome sequencing, which in the future could become an affordable method for the guidance of treatment decisions, especially in high-burden/resource-limited settings. More recently, MDR-TB treatment outcomes have dramatically improved with the use of bedaquiline-based regimens. Ongoing clinical trials with novel and repurposed drugs will potentially further improve cure-rates, and may substantially decrease the duration of MDR-TB treatment necessary to achieve relapse-free cure.

Cross border, highly individualised treatment of a patient with challenging extensively drug-resistant tuberculosis

Extensively drug-resistant (XDR) tuberculosis (TB) is defined by resistance to isoniazid, rifampicin, any fluoroquinolone and at least one of the three second line injectable drugs, such as amikacin. Drug toxicity and duration impair adherence to treatment and outcome is rather poor [1]. We report on a particularly challenging XDR-TB patient with persistent non-adherence to treatment and an exceptionally complex drug susceptibility pattern.

Crossing borders by treating a patient with difficult to treat XDR-TB; highly individualised but holistic approachhttp://ow.ly/JyjK30ielsD

Comorbidities and treatment outcomes in multidrug resistant tuberculosis: a systematic review and meta-analysis

Little is known about the impact of comorbidities on multidrug resistant (MDR) and extensively drug resistant (XDR) tuberculosis (TB) treatment outcomes. We aimed to examine the effect of human immunodeficiency virus (HIV), diabetes, chronic kidney disease (CKD), alcohol misuse, and smoking on MDR/XDRTB treatment outcomes. We searched MEDLINE, EMBASE, Cochrane Central Registrar and Cochrane Database of Systematic Reviews as per PRISMA guidelines. Eligible studies were identified and treatment outcome data were extracted. We performed a meta-analysis to generate a pooled relative risk (RR) for unsuccessful outcome in MDR/XDRTB treatment by co-morbidity. From 2457 studies identified, 48 reported on 18,257 participants, which were included in the final analysis. Median study population was 235 (range 60-1768). Pooled RR of unsuccessful outcome was higher in people living with HIV (RR = 1.41 [95%CI: 1.15-1.73]) and in people with alcohol misuse (RR = 1.45 [95%CI: 1.21-1.74]). Outcomes were similar in people with diabetes or in people that smoked. Data was insufficient to examine outcomes in exclusive XDRTB or CKD cohorts. In this systematic review and meta-analysis, alcohol misuse and HIV were associated with higher pooled OR of an unsuccessful outcome in MDR/XDRTB treatment. Further research is required to understand the role of comorbidities in driving unsuccessful treatment outcomes.

The California Multidrug-Resistant Tuberculosis Consult Service: a partnership of state and local programs

Background: The US Centers for Disease Control and Prevention recommend expert consultation for multi-drug-resistant tuberculosis (MDR-TB) cases. In 2002, the California MDR-TB Service was created to provide expert MDR-TB consultations. We describe the characteristics, treatment outcomes and management of patients referred to the Service. Methods: Surveillance data were used for descriptive analysis of cases, with consultation during July 2002-December 2012. Clinical consultation data and modified World Health Organization indicators were used to assess the care and management of cases, with consultation from January 2009 to December 2012. Results: Of 339 MDR-TB patients, 140 received a consultation. The proportion of patients receiving a consultation increased from 12% in 2002 to 63% in 2012. There were 24 pre-extensively drug-resistant TB and 5 patients with extensively drug-resistant TB. The majority (n = 123, 88%) completed treatment, 5 (4%) died, 7 (5%) moved before treatment completion, 4 (3%) stopped treatment due to an adverse event and 1 (1%) had an unknown outcome. Indicator data showed that 86% underwent rapid molecular drug susceptibility testing, 98% received at least four drugs to which they had known or presumed susceptibility, and 93% culture converted within 6 months. Conclusions: Consultations with the MDR-TB Service increased over time. Results highlight successful treatment and indicator outcomes.

Precision medicine for drug-resistant tuberculosis in high-burden countries: is individualised treatment desirable and feasible?

Treatment for drug-resistant tuberculosis is largely delivered through standardised, empirical combination regimens in low-resource, high-burden settings. However, individualised treatment, guided by detailed drug susceptibility testing, probably results in improved individual outcomes and is the standard of care in well-resourced settings. Driven by the urgent need to scale up treatment provision, new tuberculosis drugs, incorporated into standardised regimens, are being tested. Although standardised regimens are expected to improve access to treatment in high-burden settings, they are also likely to contribute to the emergence of resistance, even with good clinical management. We argue that a balance is required between the need to improve treatment access and the imperative to minimise resistance amplification and provide the highest standard of care, through a precision medicine approach. In tuberculosis, as in other diseases, we should aim to reduce the entrenched inequalities that manifest as different standards of care in different settings.

Case Report: Carbapenemase-Producing Enterobacteriaceae in an Asylum Seeker with Multidrug-Resistant Tuberculosis

A Syrian asylum seeker with multidrug-resistant tuberculosis (TB) developed a bronchopleural fistula after pneumonectomy. Although screening tests were negative on admission, carbapenemase-producing Enterobacteriaceae were cultured after a few months of TB treatment. Prevalence of multidrug-resistant organisms is reported to be increased in asylum seekers compared with the general Dutch population. Arduous conditions during transit and interrupted health care delivery in our patient led to multiple-resistant microorganisms that complicated treatment.

High Rates of Treatment Success in Pulmonary Multidrug-Resistant Tuberculosis by Individually Tailored Treatment Regimens

RATIONALE

We evaluated whether treatment outcomes for patients with multidrug-resistant and extensively drug-resistant tuberculosis can be substantially improved when sufficient resources for personalizing medical care are available.

OBJECTIVES

To describe the characteristics and outcomes of patients with pulmonary multidrug-resistant tuberculosis at the Otto Wagner Hospital in Vienna, Austria.

METHODS

We conducted a retrospective single-center study of patients initiated on treatment for multi-drug resistant tuberculosis between January 2003 and December 2012 at the Otto Wagner Hospital, Vienna, Austria. The records of patients with multidrug-resistant tuberculosis were reviewed for epidemiological, clinical, laboratory, treatment, and outcome data.

MEASUREMENTS AND MAIN RESULTS

Ninety patients with pulmonary multidrug-resistant tuberculosis were identified. The median age was 30 years (interquartile range, 26-37). All patients were of non-Austrian origin, and 70 (78%) came from former states of the Soviet Union. Thirty-nine (43%) patients had multidrug-resistant tuberculosis; 28 (31%) had additional bacillary resistance to at least one second-line injectable drug and 9 (10%) to a fluoroquinolone. Fourteen (16%) patients had extensively drug-resistant tuberculosis. Eighty-eight different drug combinations were used for the treatment of the 90 patients. Surgery was performed on 10 (11.1%) of the patients. Sixty-five (72.2%) patients had a successful treatment outcome, 8 (8.9%) defaulted, 3 (3.3%) died, 8 (8.9%) continued treatment in another country and their outcome was unknown, and 6 (6.7%) were still on therapy. None of the patients experienced treatment failure. Treatment outcomes for patients with extensively drug-resistant tuberculosis were similar to those of patients with multidrug-resistant tuberculosis.

CONCLUSIONS

High rates of treatment success can be achieved in patients with multidrug-resistant and extensively drug-resistant tuberculosis when individually tailored treatment regimens can be provided in a high-resource setting.

Adverse Effects and Choice between the Injectable Agents Amikacin and Capreomycin in Multidrug-Resistant Tuberculosis

The prolonged use of injectable agents in a regimen for the treatment of multidrug-resistant tuberculosis (MDR-TB) is recommended by the World Health Organization, despite its association with ototoxicity and nephrotoxicity. We undertook this study to look at the relative adverse effects of capreomycin and amikacin. We reviewed the case notes of 100 consecutive patients treated at four MDR-TB treatment centers in the United Kingdom. The median total duration of treatment with an injectable agent was 178 days (interquartile range [IQR], 109 to 192 days; n = 73) for those with MDR-TB, 179 days (IQR, 104 to 192 days; n = 12) for those with MDR-TB plus fluoroquinolone resistance, and 558 days (IQR, 324 to 735 days; n = 8) for those with extensively drug-resistant tuberculosis (XDR-TB). Injectable use was longer for those started with capreomycin (183 days; IQR, 123 to 197 days) than those started with amikacin (119 days; IQR, 83 to 177 days) (P = 0.002). Excluding patients with XDR-TB, 51 of 85 (60%) patients were treated with an injectable for over 6 months and 12 of 85 (14%) were treated with an injectable for over 8 months. Forty percent of all patients discontinued the injectable due to hearing loss. Fifty-five percent of patients experienced ototoxicity, which was 5 times (hazard ratio [HR], 5.2; 95% confidence interval [CI], 1.2 to 22.6; P = 0.03) more likely to occur in those started on amikacin than in those treated with capreomycin only. Amikacin was associated with less hypokalemia than capreomycin (odds ratio, 0.28; 95% CI, 0.11 to 0.72), with 5 of 37 (14%) patients stopping capreomycin due to recurrent electrolyte loss. There was no difference in the number of patients experiencing a rise in the creatinine level of >1.5 times the baseline level. Hearing loss is frequent in this cohort, though its incidence is significantly lower in those starting capreomycin, which should be given greater consideration as a first-line agent.

The importance of clinical pharmacokinetic-pharmacodynamic studies in unraveling the determinants of early and late tuberculosis outcomes

Tuberculosis remains a major infectious cause of morbidity and mortality worldwide. Current antibiotic regimens, constructed prior to the development of modern pharmacokinetic-pharmacodynamic (PK–PD) tools, are based on incomplete understanding of exposure–response relationships in drug susceptible and multidrug resistant tuberculosis. Preclinical and population PK data suggest that clinical PK–PD studies may enable therapeutic drug monitoring for some agents and revised dosing for others. Future clinical PK–PD challenges include: incorporation of PK methods to assay free concentrations for all active metabolites; selection of appropriate early outcome measures which reflect therapeutic response; elucidation of genetic contributors to interindividual PK variability; conduct of targeted studies on special populations (including children); and measurement of PK–PD parameters at the site of disease.

Sharing the spotlight in Durban: A report from IAS TB2016 at AIDS2016

Tuberculosis (TB) is now recognized as the number one cause of death worldwide due to a single infectious pathogen and is the cause of death in one-third of people living with HIV worldwide. An inaugural pre-conference focused on TB (TB2016) was held at the International AIDS Society Conference AIDS2016. This report focuses on key messages from the TB2016 conference that are important for the medical, public health, activist, and scientific communities.

Long-term outcome and safety of prolonged bedaquiline treatment for multidrug-resistant tuberculosis

Bedaquiline, a recently approved drug for the treatment of multidrug-resistant tuberculosis (MDR-TB), is recommended for a duration of 24 weeks. There are scarce data on patients treated with this drug outside clinical trials.

All MDR-TB patients who started treatment from January 1, 2011 to December 31, 2013 and received ≥30 days of bedaquiline were included in a multicentre observational cohort.

Among 45 MDR-TB patients, 53% harboured isolates resistant to both fluoroquinolones and second-line injectables, and 38% harboured isolates resistant to one of these drug classes. Median bedaquiline treatment duration was 361 days and 33 patients (73%) received prolonged (>190 days) bedaquiline treatment. Overall, 36 patients (80%) had favourable outcome, five were lost to follow-up, three died, and one failed and acquired bedaquiline resistance. No cases of recurrence were reported. Severe and serious adverse events were recorded in 60% and 18% of patients, respectively. Values of Fridericia-corrected QT interval (QTcF) >500 ms were recorded in 11% of patients, but neither arrhythmias nor symptomatic cardiac side-effects occurred. Bedaquiline was discontinued in three patients following QTcF prolongation. No significant differences in outcomes or adverse events rates were observed between patients receiving standard and prolonged bedaquiline treatment.

Bedaquiline-containing regimens achieved favourable outcomes in a large proportion of patients. Prolonged bedaquiline treatment was overall well tolerated in this cohort.

Drug resistant TB: UK multicentre study (DRUMS): Treatment, management and outcomes in London and West Midlands 2008-2014

OBJECTIVES

Detailed information regarding treatment practices and outcomes of MDR-TB treatment in the UK is required as a baseline for care improvements.

METHODS

100 consecutive cases between 2008 and 2014 were reviewed retrospectively at 4 MDR-TB treatment centres in England to obtain information on drug treatment choices, hospital admission duration and outcomes for MDR-TB.

RESULTS

Initial hospital admission was long, median 62.5 (IQR 20-106, n = 92) days, and 13% (12/92) of patients lost their home during this period. Prolonged admission was associated with pulmonary cases, cavities on chest radiograph, a public health policy of waiting for sputum culture conversion (CC) and loss of the patient's home. Sputum CC occurred at a median of 33.5 (IQR 16-55, n = 46) days. Treatment success was high (74%, 74/100) and mortality low (1%, 1/100). A significant proportion of the cohort had "neutral" results due to deportation and transfer overseas (12%, (12/100)). 14% (14/100) had negative outcomes for which poor adherence was the main reason (62%, 9/14).

CONCLUSIONS

Successful outcome is common in recognised centres and limited by adherence rather than microbiological failure. Duration of hospital admission is influenced by lack of suitable housing and some variation in public health practice. Wider access to long-term assisted living facilities could improve completion rates.

Individualizing management of extensively drug-resistant tuberculosis: diagnostics, treatment, and biomarkers

INTRODUCTION

Success rates for treatment of extensively drug resistant tuberculosis (XDR-TB) are low due to limited treatment options, delayed diagnosis and inadequate health care infrastructure. Areas covered: This review analyses existing programmes of prevention, diagnosis and treatment of XDR-TB. Improved diagnostic procedures and rapid molecular tests help to select appropriate drugs and dosages. Drugs dosages can be further tailored to the specific conditions of the patient based on quantitative susceptibility testing of the M. tuberculosis isolate and use of therapeutic drug monitoring. Pharmacovigilance is important for preserving activity of the novel drugs bedaquiline and delamanid. Furthermore, biomarkers of treatment response must be developed and validated to guide therapeutic decisions. Expert commentary: Given the currently poor treatment outcomes and the association of XDR-TB with HIV in endemic regions, a more patient oriented approach regarding diagnostics, drug selection and tailoring and treatment evaluation will improve treatment outcome. The different areas of expertise should be covered by a multidisciplinary team and may involve the transition of patients from hospitalized to home or community-based treatment.

Mechanisms of action and therapeutic efficacies of the lipophilic antimycobacterial agents clofazimine and bedaquiline

Drug-resistant (DR)-TB is the major challenge confronting the global TB control programme, necessitating treatment with second-line anti-TB drugs, often with limited therapeutic efficacy. This scenario has resulted in the inclusion of Group 5 antibiotics in various therapeutic regimens, two of which promise to impact significantly on the outcome of the therapy of DR-TB. These are the 're-purposed' riminophenazine, clofazimine, and the recently approved diarylquinoline, bedaquiline. Although they differ structurally, both of these lipophilic agents possess cationic amphiphilic properties that enable them to target and inactivate essential ion transporters in the outer membrane of Mycobacterium tuberculosis. In the case of bedaquiline, the primary target is the key respiratory chain enzyme F₁/F₀-ATPase, whereas clofazimine is less selective, apparently inhibiting several targets, which may underpin the extremely low level of resistance to this agent. This review is focused on similarities and differences between clofazimine and bedaquiline, specifically in respect of molecular mechanisms of antimycobacterial action, targeting of quiescent and metabolically active organisms, therapeutic efficacy in the clinical setting of DR-TB, resistance mechanisms, pharmacodynamics, pharmacokinetics and adverse events.

Immunoassay Analysis of Kanamycin in Serum Using the Tobramycin Kit

Kanamycin is one of the aminoglycosides used in the treatment of multidrug-resistant tuberculosis. Blood concentrations of kanamycin are predictive for the treatment efficacy and the occurrence of side effects, and dose adjustments can be needed to optimize therapy. However, an immunoassay method for the quantification of kanamycin is not commercially available. We modified the existing tobramycin immunoassay to analyze kanamycin. This modified method was tested in a concentration range of 0.3 to 80.0 mg/liter for inaccuracy and imprecision. In addition, the analytical results of the immunoassay method were compared to those obtained by a liquid chromatography-tandem mass spectrometry (LC-MS/MS) analytical method using Passing and Bablok regression. Within-day imprecision varied from 2.3 to 13.3%, and between-day imprecision ranged from 0.0 to 11.3%. The inaccuracy ranged from -5.2 to 7.6%. No significant cross-reactivity with other antimicrobials and antiviral agents was observed. The results of the modified immunoassay method were comparable with the LC-MS/MS analytical outcome. This new immunoassay method enables laboratories to perform therapeutic drug monitoring of kanamycin without the need for complex and expensive LC-MS/MS equipment.

PET/CT imaging of Mycobacterium tuberculosis infection

Tuberculosis has a high morbidity and mortality worldwide. Mycobacterium tuberculosis (Mtb) has a complex pathophysiology; it is an aerobic bacillus capable of surviving in anaerobic conditions in a latent state for a very long time before reactivation to active disease. In the latent tuberculosis infection, the individual has no clinical evidence of active disease, but exhibits a hypersensitive response to proteins of Mtb. Only some 5–10 % of latently infected individuals appear to have reactivation of tuberculosis at any one time point after infection, and neither imaging nor immune tests have been shown to predict tuberculosis reactivation reliably. The complex pathology of the organism provides multiple molecular targets for imaging the infection and targeting therapy. Positron emission tomography (PET) integrated with computer tomography (CT) provides a unique opportunity to noninvasively image the whole body for diagnosing, staging and assessing therapy response in many infectious and inflammatory diseases. PET/CT is a powerful noninvasive tool that can rapidly provide three-dimensional views of disease deep within the body and conduct longitudinal assessment over time in one particular patient. Some PET tracers, such as ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG), have been found to be useful in various infectious diseases for detection, assessing disease activity, staging and monitoring response to therapy. This tracer has also been used for imaging tuberculosis. ¹⁸F-FDG PET relies on the glucose uptake of inflammatory cells as a result of the respiratory burst that occurs with infection. Other PET tracers have also been used to image different aspects of the pathology or microbiology of Mtb. The synthesis of the complex cell membrane of the bacilli for example can be imaged with ¹¹C-choline or ¹⁸F-fluoroethylcholine PET/CT while the uptake of amino acids during cell growth can be imaged by 3′-deoxy-3′-[¹⁸F]fluoro-l-thymidine. PET/CT provides a noninvasive and sensitive method of assessing histopathological information on different aspects of tuberculosis and is already playing a role in the management of tuberculosis. As our understanding of the pathophysiology of tuberculosis increases, the role of PET/CT in the management of this disease would become more important. In this review, we highlight the various tracers that have been used in tuberculosis and explain the underlying mechanisms for their use.

Association between Directly Observed Therapy and Treatment Outcomes in Multidrug-Resistant Tuberculosis: A Systematic Review and Meta-Analysis

Background

Multidrug-resistant tuberculosis (MDR-TB) represents a major obstacle towards successful TB control. Directly observed therapy (DOT) was recommended by WHO to improve adherence and treatment outcomes of MDR-TB patients, however, the effectiveness of DOT on treatment outcomes of MDR-TB patients was mixed in previous studies. We conducted this systematic review and meta-analysis to assess the association between DOT and treatment outcomes and to examine the impact of different DOT providers and DOT locations on successful treatment outcomes in MDR-TB patients.

Methods

We searched studies published in English between January 1970 and December 2015 in major electronic databases. Two reviewers independently screened articles and extracted information of DOT, treatment success rate and other characteristics of studies. Random effects model was used to calculate the pooled treatment success rate and 95% confidence interval (CI). Sub-group analyses were conducted to access factors associated with successful treatment outcomes.

Results

A total of 31 articles 7,466 participants were included. Studies reporting full DOT (67.4%, 95% CI: 61.4–72.8%) had significantly higher pooled treatment success rates than those reporting self-administration therapy (46.9%, 95% CI: 41.4–52.4%). No statistically difference was found among DOT provided by healthcare providers (65.8%, 95% CI: 55.7–74.7%), family members (72.0%, 95% CI: 31.5–93.5%) and private DOT providers (69.5%, 95% CI: 57.0–79.7%); and neither did we find significantly difference on pooled treatment success rates between patients having health facility based DOT (70.5%, 95% CI: 61.5–78.1%) and home-based DOT (68.4%, 95% CI: 51.5–81.5%).

Conclusion

Providing DOT for a full course of treatment associated with a higher treatment success rate in MDR-TB patients.

[Drug-resistant tuberculosis. Epidemiology, diagnostics and therapy]

Drug-resistant tuberculosis (DR-TB) is one of the serious problems in the fight against tuberculosis on a global scale. This review article describes in brief the global epidemiology, diagnostics and treatment of DR-TB. The situation in Germany, Switzerland and Austria is addressed in detail. The article concludes with a presentation of current research topics in the field of resistant TB.