Evaluating newly approved drugs in combination regimens for multidrug-resistant tuberculosis with fluoroquinolone resistance (endTB-Q): study protocol for a multi-country randomized controlled trial.

BACKGROUND: Treatment for fluoroquinolone-resistant multidrug-resistant/rifampicin-resistant tuberculosis (pre-XDR TB) often lasts longer than treatment for less resistant strains, yields worse efficacy results, and causes substantial toxicity. The newer anti-tuberculosis drugs, bedaquiline and delamanid, and repurposed drugs clofazimine and linezolid, show great promise for combination in shorter, less-toxic, and effective regimens. To date, there has been no randomized, internally and concurrently controlled trial of a shorter, all-oral regimen comprising these newer and repurposed drugs sufficiently powered to produce results for pre-XDR TB patients. METHODS: endTB-Q is a phase III, multi-country, randomized, controlled, parallel, open-label clinical trial evaluating the efficacy and safety of a treatment strategy for patients with pre-XDR TB. Study participants are randomized 2:1 to experimental or control arms, respectively. The experimental arm contains bedaquiline, linezolid, clofazimine, and delamanid. The control comprises the contemporaneous WHO standard of care for pre-XDR TB. Experimental arm duration is determined by a composite of smear microscopy and chest radiographic imaging at baseline and re-evaluated at 6 months using sputum culture results: participants with less extensive disease receive 6 months and participants with more extensive disease receive 9 months of treatment. Randomization is stratified by country and by participant extent-of-TB-disease phenotype defined according to screening/baseline characteristics. Study participation lasts up to 104 weeks post randomization. The primary objective is to assess whether the efficacy of experimental regimens at 73 weeks is non-inferior to that of the control. A sample size of 324 participants across 2 arms affords at least 80% power to show the non-inferiority, with a one-sided alpha of 0.025 and a non-inferiority margin of 12%, against the control in both modified intention-to-treat and per-protocol populations. DISCUSSION: This internally controlled study of shortened treatment for pre-XDR TB will provide urgently needed data and evidence for clinical and policy decision-making around the treatment of pre-XDR TB with a four-drug, all-oral, shortened regimen. TRIAL REGISTRATION: ClinicalTrials.Gov NCT03896685. Registered on 1 April 2018; the record was last updated for study protocol version 4.3 on 17 March 2023.

Outcomes of WHO-conforming, longer, all-oral multidrug-resistant TB regimens and analysis implications.

BACKGROUND: Evidence of the effectiveness of the WHO-recommended design of longer individualized regimens for multidrug- or rifampicin-resistant TB (MDR/RR-TB) is limited.OBJECTIVES: To report end-of-treatment outcomes for MDR/RR-TB patients from a 2015-2018 multi-country cohort that received a regimen consistent with current 2022 WHO updated recommendations and describe the complexities of comparing regimens.METHODS: We analyzed a subset of participants from the endTB Observational Study who initiated a longer MDR/RR-TB regimen that was consistent with subsequent 2022 WHO guidance on regimen design for longer treatments. We excluded individuals who received an injectable agent or who received fewer than four likely effective drugs.RESULTS: Of the 759 participants analyzed, 607 (80.0%, 95% CI 77.0-82.7) experienced successful end-of-treatment outcomes. The frequency of success was high across groups, whether stratified on number of Group A drugs or fluoroquinolone resistance, and ranged from 72.1% to 90.0%. Regimens were highly variable regarding composition and the duration of individual drugs.CONCLUSIONS: Longer, all-oral, individualized regimens that were consistent with 2022 WHO guidance on regimen design had high frequencies of treatment success. Heterogeneous regimen compositions and drug durations precluded meaningful comparisons. Future research should examine which combinations of drugs maximize safety/tolerability and effectiveness.

Concordance of three approaches for operationalizing outcome definitions for multidrug-resistant TB.

BACKGROUND: The WHO provides standardized outcome definitions for rifampicin-resistant (RR) and multidrug-resistant (MDR) TB. However, operationalizing these definitions can be challenging in some clinical settings, and incorrect classification may generate bias in reporting and research. Outcomes calculated by algorithms can increase standardization and be adapted to suit the research question. We evaluated concordance between clinician-assigned treatment outcomes and outcomes calculated based on one of two standardized algorithms, one which identified failure at its earliest possible recurrence (i.e., failure-dominant algorithm), and one which calculated the outcome based on culture results at the end of treatment, regardless of early occurrence of failure (i.e., success-dominant algorithm).METHODS: Among 2,525 patients enrolled in the multi-country endTB observational study, we calculated the frequencies of concordance using cross-tabulations of clinician-assigned and algorithm-assigned outcomes. We summarized the common discrepancies.RESULTS: Treatment success calculated by algorithms had high concordance with treatment success assigned by clinicians (95.8 and 97.7% for failure-dominant and success-dominant algorithms, respectively). The frequency and pattern of the most common discrepancies varied by country.CONCLUSION: High concordance was found between clinician-assigned and algorithm-assigned outcomes. Heterogeneity in discrepancies across settings suggests that using algorithms to calculate outcomes may minimize bias.

Evaluating newly approved drugs for multidrug-resistant tuberculosis (endTB): study protocol for an adaptive, multi-country randomized controlled trial.

BACKGROUND: Treatment of multidrug- and rifampin-resistant tuberculosis (MDR/RR-TB) is expensive, labour-intensive, and associated with substantial adverse events and poor outcomes. While most MDR/RR-TB patients do not receive treatment, many who do are treated for 18 months or more. A shorter all-oral regimen is currently recommended for only a sub-set of MDR/RR-TB. Its use is only conditionally recommended because of very low-quality evidence underpinning the recommendation. Novel combinations of newer and repurposed drugs bring hope in the fight against MDR/RR-TB, but their use has not been optimized in all-oral, shorter regimens. This has greatly limited their impact on the burden of disease. There is, therefore, dire need for high-quality evidence on the performance of new, shortened, injectable-sparing regimens for MDR-TB which can be adapted to individual patients and different settings. METHODS: endTB is a phase III, pragmatic, multi-country, adaptive, randomized, controlled, parallel, open-label clinical trial evaluating the efficacy and safety of shorter treatment regimens containing new drugs for patients with fluoroquinolone-susceptible, rifampin-resistant tuberculosis. Study participants are randomized to either the control arm, based on the current standard of care for MDR/RR-TB, or to one of five 39-week multi-drug regimens containing newly approved and repurposed drugs. Study participation in all arms lasts at least 73 and up to 104 weeks post-randomization. Randomization is response-adapted using interim Bayesian analysis of efficacy endpoints. The primary objective is to assess whether the efficacy of experimental regimens at 73 weeks is non-inferior to that of the control. A sample size of 750 patients across 6 arms affords at least 80% power to detect the non-inferiority of at least 1 (and up to 3) experimental regimens, with a one-sided alpha of 0.025 and a non-inferiority margin of 12%, against the control in both modified intention-to-treat and per protocol populations. DISCUSSION: The lack of a safe and effective regimen that can be used in all patients is a major obstacle to delivering appropriate treatment to all patients with active MDR/RR-TB. Identifying multiple shorter, safe, and effective regimens has the potential to greatly reduce the burden of this deadly disease worldwide. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02754765. Registered on 28 April 2016; the record was last updated for study protocol version 3.3, on 27 August 2019.

Thin-Layer-Agar-Based Direct Phenotypic Drug Susceptibility Testing on Sputum in Eswatini Rapidly Detects Mycobacterium tuberculosis Growth and Rifampicin Resistance Otherwise Missed by WHO-Endorsed Diagnostic Tests.

Xpert MTB/RIF rapidly detects resistance to rifampicin (RR); however, this test misses I491F-RR conferring rpoB mutation, common in southern Africa. In addition, Xpert MTB/RIF does not distinguish between viable and dead Mycobacterium tuberculosis (MTB). We aimed to investigate the ability of thin-layer agar (TLA) direct drug-susceptibility testing (DST) to detect MTB and its drug-resistance profiles in field conditions in Eswatini. Consecutive samples were tested in parallel with Xpert MTB/RIF and TLA for rifampicin (1.0 µg/ml) and ofloxacin (2.0 µg/ml). TLA results were compared at the Reference Laboratory in Antwerp with indirect-DST on Löwenstein-Jensen or 7H11 solid media and additional phenotypic and genotypic testing to resolve discordance. TLA showed a positivity rate for MTB detection of 7.1% versus 10.0% for Xpert MTB/RIF. Of a total of 4,547 samples included in the study, 200 isolates were available for comparison to the composite reference. Within a median of 18.4 days, TLA detected RR with 93.0% sensitivity (95% confidence interval [CI], 77.4 to 98.0) and 99.4% specificity (95% CI, 96.7 to 99.9) versus 62.5% (95% CI, 42.7 to 78.8) and 99.3% (95% CI, 96.2 to 99.9) for Xpert MTB/RIF. Eight isolates, 28.6% of all RR-confirmed isolates, carried the I491F mutation, all detected by TLA. TLA also correctly identified 183 of the 184 ofloxacin-susceptible isolates (99.5% specificity; 95% CI, 97.0 to 99.9). In field conditions, TLA rapidly detects RR, and in this specific setting, it contributed to detection of additional RR patients over Xpert MTB/RIF, mainly but not exclusively due to I491F. TLA also accurately excluded fluoroquinolone resistance.

Introducing new and repurposed TB drugs: the endTB experience.

In 2015, the initiative Expand New Drug Markets for TB (endTB) began, with the objective of reducing barriers to access to the new and repurposed TB drugs. Here we describe the major implementation challenges encountered in 17 endTB countries. We provide insights on how national TB programmes and other stakeholders can scale-up the programmatic use of new and repurposed TB drugs, while building scientific evidence about their safety and efficacy. For any new drug or diagnostic, multiple market barriers can slow the pace of scale-up. During 2015-2019, endTB was successful in increasing the number of patients receiving new and repurposed TB drugs in 17 countries. The endTB experience has many lessons, which are relevant to country level introduction of new TB drugs, as well as non-TB drugs and diagnostics. For example: the importation of TB drugs is possible even in the absence of registration; emphasis on good clinical monitoring is more important than pharmacovigilance reporting; national guidelines and expert committees can both facilitate and hinder innovative practice; clinicians use new and repurposed TB drugs when they are available; data collection to generate scientific evidence requires financial and human resources; pilot projects can drive national scale-up.

Setting up pharmacovigilance based on available endTB Project data for bedaquiline.

SETTING: Active pharmacovigilance (PV) is recommended for TB programmes, notably for multidrug-resistant TB (MDR-TB) patients treated with new drugs. Launched with the support of UNITAID in April 2015, endTB (Expand New Drug markets for TB) facilitated treatment with bedaquiline (BDQ) and/or delamanid of >2600 patients in 17 countries, and contributed to the creation of a central PV unit (PVU).OBJECTIVE: To explain the endTB PVU process by describing the serious adverse events (SAEs) experienced by patients who received BDQ-containing regimens.DESIGN: The overall PV strategy was in line with the 'advanced´ WHO active TB drug safety monitoring and management (aDSM) system. All adverse events (AEs) of clinical significance were followed up; the PVU focused on signal detection from SAEs.RESULTS and CONCLUSION: Between 1 April 2015 and 31 March 2019, the PVU received and assessed 626 SAEs experienced by 417 BDQ patients. A board of MDR-TB/PV experts reviewed unexpected and possibly drug-related SAEs to detect safety signals. The experts communicated on clusters of risks factors, notably polypharmacy and off-label drug use, encouraging a patient-centred approach of care. Organising advanced PV in routine care is possible but demanding. It is reasonable to expect local/national programmes to focus on clinical management, and to limit reporting to aDSM systems to key data, such as the SAEs.

What is the best culture conversion prognostic marker for patients treated for multidrug-resistant tuberculosis?

INTRODUCTION: Identification of good prognostic marker for tuberculosis (TB) treatment response is a necessary step on the path towards a surrogate marker to reduce TB trial duration.METHODS: We performed a retrospective analysis on routinely collected data in 6 drug-resistant TB (DRTB) programs. Culture conversion, defined as two consecutive negative cultures, was assessed, and performance of culture conversion at Month 2 and Month 6 to predict treatment success were explored. To explore factors associated with positive predicted value (PPV) and the specificity of culture conversion, a multinomial logistic regression was fitted.RESULTS: This study included 634 patients: 68.5% were males; the median age was 35 years, 75.2% were previously treated for TB, 59.4% were resistant only to isoniazid and rifampicin and 18.1% resistant to fluoroquinolones. Culture conversion at Month 2 and 6 showed similar PPV while specificity was much higher for culture conversion at Month 2: 91.3% (95%CI 86.1-95.1). PPV of culture conversion at Month 2 did not vary strongly according to patients' characteristics, while specificity was slightly higher among patients with fluoroquinolone-resistant strains.CONCLUSION: Culture conversion at Month 2 is an acceptable prognostic marker for MDR-TB treatment. Considering the advantage of using an earlier marker, further evaluation as a surrogate marker is warranted to shorten TB trials.

What will it take to eliminate drug-resistant tuberculosis?

Drug-resistant tuberculosis (DR-TB) is challenging to diagnose, treat, and prevent, but this situation is slowly changing. If the world is to drastically reduce the incidence of DR-TB, we must stop creating new DR-TB as an essential first step. The DR-TB epidemic that is ongoing should also be directly addressed. First-line drug resistance must be rapidly detected using universal molecular testing for resistance to at least rifampin and, preferably, other key drugs at initial TB diagnosis. DR-TB treatment outcomes must also improve dramatically. Effective use of currently available, new, and repurposed drugs, combined with patient-centered treatment that aids adherence and reduces catastrophic costs, are essential. Innovations within sight, such as short, highly effective, broadly indicated regimens, paired with point-of-care drug susceptibility testing, could accelerate progress in treatment outcomes. Preventing or containing resistance to second-line and novel drugs is also critical and will require high-quality systems for diagnosis, regimen selection, and treatment monitoring. Finally, earlier detection and/or prevention of DR-TB is necessary, with particular attention to airborne infection control, case finding, and preventive therapy for contacts of patients with DR-TB. Implementing these strategies can overcome the barrier that DR-TB represents for global TB elimination efforts, and could ultimately make global elimination of DR-TB (fewer than one annual case per million population worldwide) attainable. There is a strong cost-effectiveness case to support pursuing DR-TB elimination; however, achieving this goal will require substantial global investment plus political and societal commitment at national and local levels.

Barriers and facilitators to early access of bedaquiline and delamanid for MDR-TB: a mixed-methods study.

SETTING: Phase II trials for bedaquiline (BDQ) and delamanid (DLM) were completed by 2011 and the drugs were approved by stringent regulatory authorities for the treatment of multidrug-resistant tuberculosis (MDR-TB) between 2012 and 2014. Manufacturers established 'early access' mechanisms to provide drugs before local registration. OBJECTIVE: To inform improvements in early access, we explored experiences of providers and advocates in accessing BDQ and DLM before the end of 2015 using a mixed-methods design. DESIGN: We examined barriers and facilitators to early access through an electronic survey. Barriers and facilitators were classified as occurring at the manufacturer- or country-level. We identified themes using inductive content analysis and illustrated themes through case studies. RESULTS: We analysed 41 survey responses from 36 respondents reporting on 22 countries; early access was attempted in 30 (73%) survey responses. Eligibility restrictions (11/30, 37%) and complicated and slow processes (8/30, 27%) were manufacturer-level barriers; access to companion drugs (10, 33%) and importation difficulties (4, 13%) were country-level barriers. Previous experience with manufacturer (3/30, 10%) and country processes (2/30, 7%) facilitated access. Eight case studies show the human impact of barriers and facilitators. CONCLUSION: Manufacturers and countries should develop transparent processes to permit early access, particularly for diseases that largely affect the poor, such as MDR-TB. Developers should plan for this need and rapidly register drugs with proven benefit, prioritizing high-burden settings.

Is 6 months of bedaquiline enough? Results from the compassionate use of bedaquiline in Armenia and Georgia.

BACKGROUND AND SETTING: Bedaquiline (BDQ) was initially only available through compassionate use programmes. OBJECTIVE: To assess the effectiveness and safety of multidrug-resistant tuberculosis (MDR-TB) treatment containing BDQ. METHOD: Retrospective analysis of data from patients receiving BDQ through compassionate use in Armenia and Georgia from April 2013 to April 2015. Logistic regression was used to assess the risk factors associated with unsuccessful treatment outcomes. RESULTS: Of 82 patients included, 84.2% (69/82) had fluoroquinolone-resistant MDR-TB and 43.4% (23/53) were seropositive for the hepatitis C virus (HCV). The culture conversion rate was 84.4% (54/64), and 18.5% (10/54) reverted back to positive. In total, 79.3% (65/82) of the patients reported at least one adverse event. Serious adverse events were reported in 14 patients, with 10/14 patients experiencing fatal outcomes-6/10 related to advanced TB and 2/10 assessed as possibly related to BDQ. Treatment outcomes were as follows: 58.5% treatment success, 12.2% deaths, 7.3% failures and 21.9% lost to follow-up. HCV coinfection was associated with unsuccessful outcomes (adjusted OR 4.45, 95%CI 1.23-16.13). CONCLUSION: BDQ through compassionate use showed relatively good success rates and safety profiles in a cohort with difficult-to-treat MDR-TB. High rates of reversion may indicate that >24 weeks of BDQ is necessary in some cases. HCV coinfection should be diagnosed and treatment considered in MDR-TB patients.

Outcomes from the first multidrug-resistant tuberculosis programme in Kenya.

SETTING: In March 2006, the first multidrug-resistant tuberculosis (MDR-TB) treatment programme was implemented in Kenya. OBJECTIVE: To describe patients' treatment outcomes and adverse events. DESIGN: A retrospective case note review of patients started on MDR-TB treatment at two Médecins Sans Frontières-supported sites and the national referral hospital of Kenya was undertaken. Sites operated an ambulatory model of care. Patients were treated for a minimum of 24 months with at least 4-5 drugs for the intensive phase of treatment, including an injectable agent. RESULTS: Of 169 patients, 25.6% were human immunodeficiency virus (HIV) positive and 89.3% were culture-positive at baseline. Adverse events occurred in 67.4% of patients: 45.9% had nausea/vomiting, 43.9% electrolyte disturbance, 41.8% dyspepsia and 31.6% hypothyroidism. The median time to culture conversion was 2 months. Treatment outcomes were as follows: 76.6% success, 14.5% deaths, 8.3% lost to follow-up and 0.7% treatment failure. HIV-positive individuals (adjusted odds ratio [aOR] 3.51, 95% confidence interval [CI] 1.12-11.03) and women (aOR 2.73, 95%CI 1.01-7.39) had a higher risk of unfavourable outcomes, while the risk was lower in those with culture conversion at 6 months (aOR 0.11, 95%CI 0.04-0.32). CONCLUSION: In Kenya, where an ambulatory model of care is used for MDR-TB treatment, treatment success was high, despite high rates of HIV. Almost half of the patients experienced electrolyte disturbance and one third had hypothyroidism; this supports the view that systematic regular biochemical monitoring is needed in Kenya.

Identification of patients who could benefit from bedaquiline or delamanid: a multisite MDR-TB cohort study.

BACKGROUND: The World Health Organization recommends adding bedaquiline or delamanid to multidrug-resistant tuberculosis (MDR-TB) regimens for which four effective drugs are not available, and delamanid for patients at high risk of poor outcome. OBJECTIVE: To identify patients at risk of unfavourable outcomes who may benefit from the new drugs. METHODS: Retrospective cohort study of treatment outcomes involving four to five effective drugs for 15-24 months in programmes in Uzbekistan, Georgia, Armenia, Swaziland and Kenya between 2001 and 2011. RESULTS: Of 1433 patients, 48.5% had body mass index (BMI) <18.5 kg/m(2), 72.9% had a high bacillary load, 16.7% were resistant to two injectables, 2.9% were resistant to ofloxacin (OFX) and 3.0% had extensively drug-resistant TB (XDR-TB). Treatment success ranged from 59.7% (no second-line resistance) to 27.0% (XDR-TB). XDR-TB (aOR 8.16, 95%CI 3.22-20.64), resistance to two injectables (aOR 1.90, 95%CI 1.00-3.62) or OFX (aOR 5.56, 95%CI 2.15-14.37), past incarceration (aOR 1.88, 95%CI 1.11-3.2), history of second-line treatment (aOR 3.24, 95%CI 1.53-6.85), low BMI (aOR 2.22, 95%CI 1.56-3.12) and high bacillary load (aOR 2.32, 95%CI 1.15-4.67) were associated with unfavourable outcomes. Patients started on capreomycin rather than kanamycin were more likely to have an unfavourable outcome (aOR 1.54, 95%CI 1.04-2.28). CONCLUSION: In our cohort, patients who may benefit from bedaquiline and delamanid represented up to two thirds of all MDR-TB patients.

(Re)moving the needle: prospects for all-oral treatment for multidrug-resistant tuberculosis.

BACKGROUND: Currently recommended regimens for multidrug-resistant tuberculosis (MDR-TB) contain painful daily injections and are unsuccessful in approximately half of patients. Removal of the injectable agent to fashion all-oral regimens could transform MDR-TB treatment and access to care. OBJECTIVE: To explore evidence for all-oral treatment regimens. DESIGN: We review evidence on drugs that could be included in injection-free MDR-TB regimens. The oral drugs considered have an indication for or are recommended for off-label use for TB or MDR-TB, and have demonstrated bactericidal activity. Drugs with weak bactericidal activity should have limited prior population exposure and evidence of effectiveness in MDR-TB regimens. RESULTS: Bedaquiline, delamanid, and linezolid all display strong bactericidal activity, while clofazimine has weak bactericidal activity. They all have limited prior population exposure and demonstrated effectiveness in MDR-TB regimens. Despite widespread exposure to pyrazinamide and late-generation fluoroquinolones in the population, all are bactericidal and have shown great value when included in treatment regimens for MDR-TB. CONCLUSION: The evidence supports the use of all-oral regimens comprising new and existing drugs for MDR-TB treatment. Existing evidence of bactericidal activity and efficacy for these drugs provides a convincing argument for transitioning MDR-TB treatment towards all-oral regimens. These new regimens could mitigate the delivery, cost, and adherence challenges inherent to the current standard.

The thin-layer agar method for direct phenotypic detection of multi- and extensively drug-resistant tuberculosis.

BACKGROUND: Molecular techniques rapidly detect resistance to rifampicin (RMP) and isoniazid (INH), but do not eliminate the need for culture-based drug susceptibility testing (DST) against other drugs. The thin-layer agar (TLA) test, a non-commercial direct DST method, has demonstrated good performance for INH and RMP; however, evidence is still limited, and its applicability for DST of ofloxacin (OFX) and kanamycin (KM) is unknown. DESIGN: We compared 279 TLA DST results with those of MGIT for INH and RMP, and 280 results for OFX and KM with those of the 7H11 agar proportion method, obtained from 320 smear-positive samples from 165 Georgian TB patients. Discrepancies were solved by comparison with a composite reference standard. The prevalence of multidrug-resistant tuberculosis (TB) was 30 of 164 patients (18.3%), 2 (6.7%) of whom had extensively drug-resistant TB. RESULTS: TLA showed 94.7%, 98.2%, 100% and 78.9% sensitivity, respectively, for INH, RMP, OFX and KM, with 100% specificity. Average time to results was 7 days in TLA, 23 in MGIT and 49 for 7H11 agar. CONCLUSIONS: In low-resource settings, TLA can be applied for the rapid detection of resistance to INH, RMP and fluoroquinolones. Further studies are necessary to improve sensitivity to KM and further assess its performance for OFX and other drugs and its applicability in field conditions.

Routine use of Xpert® MTB/RIF in areas with different prevalences of HIV and drug-resistant tuberculosis.

SETTING: Despite the widespread introduction of Xpert(®) MTB/RIF in developing countries, reports of its use and value in routine conditions remain limited. OBJECTIVE: To describe Xpert results in relation to microscopy, treatment initiation, cost and workload under routine conditions at four sites in Cambodia, Georgia, Kenya and Swaziland. DESIGN: Laboratory and clinical information on presumed TB patients were obtained from routine registers over a period of at least 6 months between March and November 2012. RESULTS: Among the 6086 presumed TB patients included in the analysis, Xpert testing increased the number of biologically confirmed cases by 15% to 67% compared to microscopy. Up to 12% of the initial Xpert results were inconclusive. Between 56% and 83% of patients were started on treatment based on microscopy and/or Xpert results, with median delays of 1-16 days. Rifampicin resistance was detected in 3-19% of Xpert-positive patients. CONCLUSION: Despite the additional numbers of cases detected by Xpert compared to microscopy, large proportions of patients are still started on treatment empirically in routine practice. Patient and specimen flow should be optimised to reduce delays in treatment initiation. Simple, non-sputum-based point-of-care tests with high sensitivity are needed to improve TB diagnosis and management.

Decontamination methods for samples preserved in cetylpyridinium chloride and cultured on thin-layer agar.

SETTING: Long transportation times of samples to culture laboratories can lead to higher contamination rates and significant loss of viability, resulting in lower culture positivity rates. Thin-layer agar (TLA) is a sensitive culture method for the isolation of Mycobacterium tuberculosis that has been optimised with N-acetyl-L-cysteine-sodium hydroxide (NALC-NaOH) decontaminated samples. The combination of the TLA culture method and other decontamination procedures has not been extensively validated. DESIGN: Among 390 smear-positive samples, we compared the culture positivity of samples decontaminated using the Petroff method vs. NALC-NaOH neutralised with phosphate buffer (PBS), applied to samples preserved with cetylpyridinium chloride (CPC) or CPC-free, and then of CPC-preserved samples decontaminated with NALC-NaOH neutralised using Difco neutralising buffer. The sediments were inoculated on TLA, and then on MGIT 960 or Löwenstein-Jensen (LJ) as gold standards. RESULTS: Decontamination with NALC-NaOH yielded higher culture positivity in TLA than in the Petroff method, which was further enhanced by neutralising CPC with the Difco buffer. Surprisingly, culture positivity on LJ also increased after using Difco buffer, suggesting that CPC may not be completely neutralised in egg-based medium. CONCLUSIONS: After transportation in CPC, decontamination using NALC-NaOH followed by neutralisation using Difco buffer resulted in the best recovery rates for samples inoculated on TLA and on LJ.

Is introducing rapid culture into the diagnostic algorithm of smear-negative tuberculosis cost-effective?

SETTING: In 2007, the World Health Organization recommended introducing rapid Mycobacterium tuberculosis culture into the diagnostic algorithm of smear-negative pulmonary tuberculosis (TB). OBJECTIVE: To assess the cost-effectiveness of introducing a rapid non-commercial culture method (thin-layer agar), together with Löwenstein-Jensen culture to diagnose smear-negative TB at a district hospital in Kenya. DESIGN: Outcomes (number of true TB cases treated) were obtained from a prospective study evaluating the effectiveness of a clinical and radiological algorithm (conventional) against the alternative algorithm (conventional plus M. tuberculosis culture) in 380 smear-negative TB suspects. The costs of implementing each algorithm were calculated using a 'micro-costing' or 'ingredient-based' method. We then compared the cost and effectiveness of conventional vs. culture-based algorithms and estimated the incremental cost-effectiveness ratio. RESULTS: The costs of conventional and culture-based algorithms per smear-negative TB suspect were respectively €39.5 and €144. The costs per confirmed and treated TB case were respectively €452 and €913. The culture-based algorithm led to diagnosis and treatment of 27 more cases for an additional cost of €1477 per case. CONCLUSION: Despite the increase in patients started on treatment thanks to culture, the relatively high cost of a culture-based algorithm will make it difficult for resource-limited countries to afford.

Reasons for defaulting from drug-resistant tuberculosis treatment in Armenia: a quantitative and qualitative study.

SETTING: Armenia, a country with a high prevalence of drug-resistant tuberculosis (DR-TB). OBJECTIVE: To identify factors related to default from DR-TB treatment in Yerevan. DESIGN: Using a retrospective cohort design, we compared defaulters with patients who were cured, completed or failed treatment. Patients who initiated DR-TB treatment from 2005 to 2011 were included in the study. A qualitative survey was conducted including semi-structured interviews with defaulters and focus group discussions with care providers. RESULTS: Of 381 patients, 193 had achieved treatment success, 24 had died, 51 had failed treatment and 97 had defaulted. The number of drugs to which the patient was resistant at admission (aRR 1.16, 95%CI 1.05-1.27), the rate of treatment interruption based on patient's decision (aRR 1.03, 95%CI 1.02-1.05), the rate of side effects (aRR 1.18, 95%CI 1.09-1.27), and absence of culture conversion during the intensive phase (aRR 0.47, 95%CI 0.31-0.71) were independently associated with default from treatment. In the qualitative study, poor treatment tolerance, a perception that treatment was inefficient, lack of information, incorrect perception of being cured, working factors and behavioural problems were factors related to treatment default. CONCLUSION: In addition to economic reasons, poor tolerance of and poor response to treatment were the main factors associated with treatment default.