Second-line Injectable Agents Research Articles

Long-term treatment outcomes in patients with multidrug-resistant tuberculosis

ObjectivesTo describe long-term treatment outcomes in patients with multi-drug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) and validate established outcome definitions for MDR/RR-TB treatment. MethodsAmong patients with MDR/RR-TB admitted to a German MDR/RR-TB referral centre from 1 September 2002 to 29 February 2020, we compared long-term treatment outcomes derived from individual patient follow-up with treatment outcomes defined by WHO-2013, WHO-2021 and the Tuberculosis Network European Trials Group-2016. ResultsIn a total of 163 patients (mean age, 35 years; standard deviation, 13 years; 14/163 [8.6%] living with HIV; 109/163 [66.9%] men, 149/163 [91.4%] migrating to Germany within 5 years), the treatment of culture-confirmed MDR/RR-TB was initiated. Additional drug resistance to a fluoroquinolone or a second-line injectable agent was present in 15 of the 163 (9.2%) Mycobacterium tuberculosis strains; resistance against both the drug classes was present in 29 of the 163 (17.8%) strains. The median duration of MDR/RR-TB treatment was 20 months (interquartile range, 19.3–21.6 months), with a medium of five active drugs included. The median follow-up time was 4 years (47.7 months; interquartile range, 21.7–65.8 months). Among the 163 patients, cure was achieved in 25 (15.3%), 82 (50.3%) and 95 (58.3%) patients according to the outcome definitions of WHO-2013, WHO-2021, and the Tuberculosis Network European Trials Group-2016, respectively. The lost to follow-up rate was 17 of 163 (10.4%). Death was more likely in patients living with HIV (hazard ratio, 4.28; 95% confidence interval, 1.26–12.86) and older patients (hazard ratio, 1.08; 95% confidence interval, 1.05–1.12; increment of 1 year). Overall, 101/163 (62.0%) patients experienced long-term, relapse-free cure; of those, 101/122 (82.8%) patients with a known status (not lost to-follow-up or transferred out) at follow-up. ConclusionUnder optimal management conditions leveraging individualized treatment regimens, long-term, relapse-free cure from MDR/RR-TB is substantially higher than cure rates defined by current treatment outcome definitions.

Emerging threat of drug-resistant tuberculosis and trends in the era of COVID-19: A descriptive study from northwestern Nigeria

BackgroundMycobacterium tuberculosis with resistance to first line and second line anti tuberculous drugs is a serious setback in the treatment of tuberculosis (TB). The COVID-19 pandemic constitutes a serious threat that could unwind the recent gains made thus far in the control of tuberculosis. This study aims to explore the pattern of drug resistant tuberculosis (DRTB) in our institution. We also aimed to explore the changing trends of TB in the era of the COVID-19 pandemic. MethodsThis descriptive study included all DRTB patients admitted and managed in the hospital between January 2018 and December 2020. We compare TB case detection in the facility before and after COVID-19 pandemic. Drug susceptibility testing were expressed as frequencies and percentages. ResultsThe study found that there was 66.03%, 45.09% and 77.78% drop in case detection of drug-sensitive TB (DSTB), DRTB and Fluoroquinolone (FQ) resistant TB respectively in the year 2020 compared to 2019. The drop in cases was similar when the year 2020 was compared to 2018. Among the 132 patients in the cohort, resistance to isoniazid, fluoroquinolones and second-line injectable agents were reported as 23.48%, 12.88%, and 31.06% respectively. ConclusionWe question the potential reason why a drop in tuberculosis cases was observed in the year 2020 and we alert the Nigerian authorities that COVID-19 control efforts going hand-in-hand with intensified TB case finding and surveillance efforts and initiating proper TB treatment for persons with active TB are urgently needed.

Lesion Penetration and Activity Limit the Utility of Second-Line Injectable Agents in Pulmonary Tuberculosis.

ABSTRACTAmikacin and kanamycin are second-line injectables used in the treatment of multidrug-resistant tuberculosis (MDR-TB) based on the clinical utility of streptomycin, another aminoglycoside and first-line anti-TB drug. While streptomycin was tested as a single agent in the first controlled TB clinical trial, introduction of amikacin and kanamycin into MDR-TB regimens was not preceded by randomized controlled trials. A recent large retrospective meta-analysis revealed that compared with regimens without any injectable drug, amikacin provided modest benefits, and kanamycin was associated with worse outcomes. Although their long-term use can cause irreversible ototoxicity, they remain part of MDR-TB regimens because they have a role in preventing emergence of resistance to other drugs. To quantify the contribution of amikacin and kanamycin to second-line regimens, we applied two-dimensional matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging in large lung lesions, quantified drug exposure in lung and in lesions of rabbits with active TB, and measured the concentrations required to kill or inhibit growth of the resident bacterial populations. Using these metrics, we applied site-of-action pharmacokinetic and pharmacodynamic (PK-PD) concepts and simulated drug coverage in patients’ lung lesions. The results provide a pharmacological explanation for the limited clinical utility of both agents and reveal better PK-PD lesion coverage for amikacin than kanamycin, consistent with retrospective data of contribution to treatment success. Together with recent mechanistic studies dissecting antibacterial activity from aminoglycoside ototoxicity, the limited but rapid penetration of streptomycin, amikacin, and kanamycin to the sites of TB disease supports the development of analogs with improved efficacy and tolerability.

Cost comparison of nine-month treatment regimens with 20-month standardized care for the treatment of rifampicin-resistant/multi-drug resistant tuberculosis in Nigeria.

BackgroundGlobally, drug resistant tuberculosis (DR-TB) continues to be a public health threat. Nigeria, which accounts for a significant proportion of the global burden of rifampicin/multi-drug resistant-TB (RR/MDR-TB) had a funding gap of $168 million dollars for TB treatment in 2018. Since 2010, Nigeria has utilized five different models of care for RR/MDR-TB (Models A-E); Models A, B and C based on a standardized WHO-approved treatment regimen of 20–24 months, were phased out between 2015 and 2019 and replaced by Models D and E. Model D is a fully ambulatory model of 9–12 months during which a shorter treatment regimen including a second-line injectable agent is utilized. Model E is identical to Model D but has patients hospitalized for the first four months of care while Model F which is to be introduced in 2020, is a fully ambulatory, oral bedaquiline-containing shorter treatment regimen of 9–12 months. Treatment models for RR/MDR-TB of 20–24 months duration have had treatment success rates of 52–66% while shorter treatment regimens have reported success rates of 85% and above. In addition, replacing the second-line injectable agent in a shorter treatment regimen with bedaquiline has been found to further improve treatment success in patients with fluoroquinolone-susceptible RR/MDR-TB.Reliable cost data for RR/MDR-TB care are limited, specifically costs of models that utilize shorter treatment regimens and which are vital to guide Nigeria through the provision of RR/MDR-TB care at scale. We therefore conducted a cost analysis of shorter treatment regimens in use and to be used in Nigeria (Models D, E and F) and compared them to three models of longer duration utilized previously in Nigeria (Models A, B and C) to identify any changes in cost from transitioning from Models A-C to Models D-F and opportunities for cost savings.MethodsWe obtained costs for TB diagnostic and monitoring tests, in-patient and out-patient care from a previous study, inflated these costs to 2019 NGN and then converted to 2020 USD. We obtained other costs from the average of six health facilities and drug costs from the global drug facility. We modeled treatment on strict adherence to two Nigerian National guidelines for programmatic and clinical management of drug-resistant tuberculosis.ResultsWe estimated that the total costs of care from the health sector perspective for Models D, E and F were $4,334, $7,705 and $3,420 respectively. This is significantly lower than the costs of Models A, B and C which were $14,781, $12, 113, $7,572 respectively.ConclusionReplacing Models A–C with Models D and E reduced the costs of RR/MDR-TB care in Nigeria by approximately $5,470 (48%) per patient treated and transitioning from Models D and E to Model F would result in further cost savings of $914 to $4,285 (21 to 56%) for every patient placed on Model F. If the improved outcomes of patients managed using bedaquiline-containing shorter treatment regimens in other countries can be attained in Nigeria, Model F would be the recommended model for the scale up of RR/MDR-TB care in Nigeria.

Outcomes with a shorter multidrug-resistant tuberculosis regimen from Karakalpakstan, Uzbekistan.

BackgroundIn 2016, World Health Organization guidelines conditionally recommended standardised shorter 9–12-month regimens for multidrug-resistant (MDR) tuberculosis (TB) treatment. We conducted a prospective study of a shorter standardised MDR-TB regimen in Karakalpakstan, Uzbekistan.MethodsConsecutive adults and children with confirmed rifampicin-resistant pulmonary TB were enrolled between September 1, 2013 and March 31, 2015; exclusions included prior treatment with second-line anti-TB drugs, and documented resistance to ofloxacin or to two second-line injectable agents. The primary outcome was recurrence-free cure at 1 year following treatment completion.ResultsOf 146 enrolled patients, 128 were included: 67 female (52.3%), median age 30.1 (interquartile range 23.8–44.4) years. At the end of treatment, 71.9% (92 out of 128) of patients achieved treatment success, with 68% (87 out of 128) achieving recurrence-free cure at 1 year following completion. Unsuccessful outcomes during treatment included 22 (17.2%) treatment failures with fluoroquinolone-resistance amplification in 8 patients (8 out of 22, 36.4%); 12 (9.4%) lost to follow-up; and 2 (1.5%) deaths. Recurrence occurred in one patient. Fourteen patients (10.9%) experienced serious adverse events. Baseline resistance to both pyrazinamide and ethambutol (adjusted OR 6.13, 95% CI 2.01; 18.63) and adherence <95% (adjusted OR 5.33, 95% CI 1.73; 16.36) were associated with unsuccessful outcome in multivariable logistic regression.ConclusionsOverall success with a standardised shorter MDR-TB regimen was moderate with considerable treatment failure and amplification of fluoroquinolone resistance. When introducing standardised shorter regimens, baseline drug susceptibility testing and minimising missed doses are critical. High rates globally of pyrazinamide, ethambutol and ethionamide resistance raise questions of continued inclusion of these drugs in shorter regimens in the absence of drug susceptibility testing-confirmed susceptibility.

Treatment of Drug-Resistant Tuberculosis: Current Status

Drug-resistant tuberculosis (DR-TB) has been an area of growing concern and posing threat to human health worldwide. The treatment has been defined for all types of DR-TB with or without newer anti-TB drugs. multi-DR-TB (MDR-TB) patients have now choice of two types of regimen, shorter and longer regimens. Shorter regimen for treatment of subset of MDR-TB patients who have not been previously treated with second line drugs and in whom resistance to fluoroquinolones and second-line injectable agents has been excluded is given for 9 to 11 months. A longer regimen of at least five effective anti-TB drugs (ATDs) during the intensive phase is recommended, including pyrazinamide and four core second-line ATDs. Intensive phase, including injectables, should be given for at least 8 months. The total duration of treatment is at least 20 months, which can be prolonged up to 24 months depending on the response of the patient. World Health Organization (WHO) has recently revised the grouping of ATD for use in DR-TB patients in 2018 into three groups based on individual patient data meta-analysis depending on their individual efficacy, risk of relapse, treatment failure, and death. Recently, an all oral longer regimen comprising bedaquiline, pretomanid, and linezolid (BPal regime) for 6 to 9 months for extensive-DR-TB (XDR-TB) patients and those MDR-TB patients who cannot tolerate or do not respond to conventional MDR-TB regimen. These new developments will be a step forward toward establishing universal regimen to treat all types of DR-TB. This article has summarized the current evidence from literature search to date, including prevalence of DR-TB, types of regimen used and the advancement in the regimens for effective treatment of DR-TB patients.

Risk factors for unfavourable treatment outcomes among rifampicin-resistant tuberculosis patients in Tajikistan.

Tajikistan is among the 30 countries with the highest multidrug-resistant tuberculosis (MDR-TB) burden. To investigate the risk factors for unfavourable treatment outcomes among rifampicin-resistant (RR)/MDR-TB patients. Retrospective medical chart review of RR/MDR-TB patients enrolled for treatment in 2012-2013. Of 601 RR/MDR-TB patients, 58 (9.7%) had pre-extensively drug-resistant TB (pre-XDR-TB; i.e., MDR-TB with additional resistance to a fluoroquinolone or second-line injectable agent) and 45 (8%) had XDR-TB (MDR-TB with additional resistance to both). Treatment failure and death were reported in respectively 40 (7%) and 89 (15%) cases; 60 (10%) patients were lost to follow-up (LTFU). In multivariable analysis, treatment failure was associated with pre-XDR-TB (adjusted odds ratio [aOR] 3.67, 95%CI 1.47-9.18) or XDR-TB (aOR 8.61, 95%CI 3.48-21.34). Death was associated with age >45 years vs. <25 years (aOR 3.47, 95%CI 1.68-7.19) and no record of any adverse event during treatment (aOR 2.55, 95%CI 1.48-4.39). Changing place of residence during treatment was an independent predictor of LTFU (aOR 4.61, 95%CI 2.41-8.8). Our findings highlight the need for 1) the use of regimens with new anti-tuberculosis drugs; 2) good handover of TB patients and 3) effective tracing mechanisms if patients change a place of residence to prevent LTFU.

Low prevalence of MDR-TB in Lao PDR: results from the first national anti-tuberculosis drug resistance survey.

To present results of the first national anti-tuberculosis (TB) drug resistance survey conducted in Lao PDR between May 2016 and August 2017 to determine the prevalence of resistance to first-line anti-TB drugs among new and previously treated pulmonary TB cases in the country. Patients with sputum smear-positive pulmonary TB were enrolled from 42 TB laboratories distributed in 40 clusters throughout the country. Survey sites were selected using probability-proportional-to-size sampling among all diagnostic centres in the country. In addition to smear microscopy, all patients underwent Xpert MTB/RIF testing and those found positive to Mycobacterium tuberculosis underwent sputum culture and drug susceptibility testing using the proportion method on solid Löwenstein-Jensen medium. Among 1006 eligible patients, 946 sputum smear-positive and Xpert MTB/RIF positive (Mycobacterium tuberculosis detected) patients were included in the survey, comprising 897 new and 49 previously treated TB cases. The prevalence of rifampicin-resistant TB was 1.2% (95% CI: 0.5-2.0%, n=11/897) among new cases and 4.1% (95% CI: 0-9.6%, n=2/49) among previously treated cases. Among the 946 TB cases confirmed by Xpert MTB/RIF, phenotypic drug sensitivity testing was available for 820 (776 new and 44 previously treated). The prevalence of multidrug-resistant TB (MDR-TB) was 0.5% (95% CI: 0-1.0%, n=4/776) among new cases and 2.3% (95% CI: 0-6.7%, n=1/44) among previously treated cases. No resistance to second-line injectable agents nor to fluoroquinolones was detected among MDR-TB patients. The first national anti-TB drug resistance survey in Lao PDR demonstrated an encouragingly low prevalence of MDR-TB. The results appear lower than previous WHO estimates, and in line with the routine surveillance based on Xpert MTB/RIF testing (conducted among 50% of presumptive TB patients in 2017). The country should continue to expand its Xpert MTB/RIF network and strive to achieve universal drug susceptibility testing.

Improved Treatment Outcomes With Bedaquiline When Substituted for Second-line Injectable Agents in Multidrug-resistant Tuberculosis: A Retrospective Cohort Study.

Bedaquiline is used as a substitute for second-line injectable (SLI) intolerance in the treatment of multidrug-resistant (MDR) tuberculosis, but the efficacy and safety of this strategy is unknown. In this retrospective cohort study adults receiving bedaquiline substitution for MDR tuberculosis therapy, plus a matched control group who did not receive bedaquiline, were identified from the electronic tuberculosis register in the Western Cape Province, South Africa. The primary outcome measure was the proportion of patients with death, loss to follow-up, or failure to achieve sustained culture conversion at 12 months of treatment. Data from 162 patients who received bedaquiline substitution and 168 controls were analyzed; 70.6% were infected with human immunodeficiency virus. Unfavorable outcomes occurred in 35 of 146 (23.9%) patients in the bedaquiline group versus 51 of 141 (36.2%) in the control group (relative risk, 0.66; 95% confidence interval, .46 -.95). The number of patients with culture reversion was lower in those receiving bedaquiline (1 patient; 0.8%) than in controls (12 patients; 10.3%; P = .001). Delayed initiation of bedaquiline was independently associated with failure to achieve sustained culture conversion (adjusted odds ratio for every 30-day delay, 1.5; 95% confidence interval, 1.1-1.9). Mortality rates were similar at 12 months (11 deaths in each group; P = .97). Substituting bedaquiline for SLIs in MDR tuberculosis treatment resulted in improved outcomes at 12 months compared with patients who continued taking SLIs, supporting the use of bedaquiline for MDR tuberculosis treatment in programmatic settings.

Treatment and outcomes in children with multidrug-resistant tuberculosis: A systematic review and individual patient data meta-analysis.

BackgroundAn estimated 32,000 children develop multidrug-resistant tuberculosis (MDR-TB; Mycobacterium tuberculosis resistant to isoniazid and rifampin) each year. Little is known about the optimal treatment for these children.Methods and findingsTo inform the pediatric aspects of the revised World Health Organization (WHO) MDR-TB treatment guidelines, we performed a systematic review and individual patient data (IPD) meta-analysis, describing treatment outcomes in children treated for MDR-TB. To identify eligible reports we searched PubMed, LILACS, Embase, The Cochrane Library, PsychINFO, and BioMedCentral databases through 1 October 2014. To identify unpublished data, we reviewed conference abstracts, contacted experts in the field, and requested data through other routes, including at national and international conferences and through organizations working in pediatric MDR-TB. A cohort was eligible for inclusion if it included a minimum of three children (aged <15 years) who were treated for bacteriologically confirmed or clinically diagnosed MDR-TB, and if treatment outcomes were reported. The search yielded 2,772 reports; after review, 33 studies were eligible for inclusion, with IPD provided for 28 of these. All data were from published or unpublished observational cohorts. We analyzed demographic, clinical, and treatment factors as predictors of treatment outcome. In order to obtain adjusted estimates, we used a random-effects multivariable logistic regression (random intercept and random slope, unless specified otherwise) adjusted for the following covariates: age, sex, HIV infection, malnutrition, severe extrapulmonary disease, or the presence of severe disease on chest radiograph. We analyzed data from 975 children from 18 countries; 731 (75%) had bacteriologically confirmed and 244 (25%) had clinically diagnosed MDR-TB. The median age was 7.1 years. Of 910 (93%) children with documented HIV status, 359 (39%) were infected with HIV. When compared to clinically diagnosed patients, children with confirmed MDR-TB were more likely to be older, to be infected with HIV, to be malnourished, and to have severe tuberculosis (TB) on chest radiograph (p < 0.001 for all characteristics). Overall, 764 of 975 (78%) had a successful treatment outcome at the conclusion of therapy: 548/731 (75%) of confirmed and 216/244 (89%) of clinically diagnosed children (absolute difference 14%, 95% confidence interval [CI] 8%–19%, p < 0.001). Treatment was successful in only 56% of children with bacteriologically confirmed TB who were infected with HIV who did not receive any antiretroviral treatment (ART) during MDR-TB therapy, compared to 82% in children infected with HIV who received ART during MDR-TB therapy (absolute difference 26%, 95% CI 5%–48%, p = 0.006). In children with confirmed MDR-TB, the use of second-line injectable agents and high-dose isoniazid (15–20 mg/kg/day) were associated with treatment success (adjusted odds ratio [aOR] 2.9, 95% CI 1.0–8.3, p = 0.041 and aOR 5.9, 95% CI 1.7–20.5, p = 0.007, respectively). These findings for high-dose isoniazid may have been affected by site effect, as the majority of patients came from Cape Town. Limitations of this study include the difficulty of estimating the treatment effects of individual drugs within multidrug regimens, only observational cohort studies were available for inclusion, and treatment decisions were based on the clinician’s perception of illness, with resulting potential for bias.ConclusionsThis study suggests that children respond favorably to MDR-TB treatment. The low success rate in children infected with HIV who did not receive ART during their MDR-TB treatment highlights the need for ART in these children. Our findings of individual drug effects on treatment outcome should be further evaluated.

Multidrug-resistant tuberculosis in Australia, 1998-2012.

To describe the epidemiology and outcomes of multidrug-resistant tuberculosis (MDR-TB) diagnosed in Australia between 1998 and 2012. A retrospective review was undertaken involving all patients with laboratory-confirmed MDR-TB notified in Australia between 1998 and 2012 inclusive. Demographic, clinical and laboratory features are described. Clinical outcomes were defined according to World Health Organization definitions of treatment success (cure and treatment completion), treatment failure, death, loss to follow-up (including transfer out), or not evaluated at treatment completion. A total of 244 cases of MDR-TB were diagnosed in Australia during the study period, representing 1.4% of all TB cases notified. The majority were born outside Australia, including one third in Papua New Guinea. Of those with treatment outcome data available, treatment success was demonstrated in 81%. Treatment success was positively associated with use of a second-line injectable agent. Those born in Papua New Guinea were less likely to achieve treatment success. MDR-TB is uncommon in Australia. The large number of cases born in Papua New Guinea, and the poorer outcomes in this cohort, represent challenges with cross-border management of MDR-TB in the Torres Strait. Australia has an ongoing role in the prevention and management of MDR-TB locally and in the region.

Alarming levels of multidrug-resistant tuberculosis in Ukraine: results from the first national survey.

The true prevalence of multidrug-resistant tuberculosis (MDR-TB) in Ukraine is not known. Available data are a decade old and limited to only one province. To determine the prevalence of MDR-TB among new and previously treated TB cases in Ukraine and explore the risk factors associated with drug resistance. A total of 1550 sputum smear-positive pulmonary TB patients were recruited from 40 clusters throughout Ukraine. Sputum specimens were examined using culture, drug susceptibility testing and pncA gene sequencing. The proportion of MDR-TB among new and previously treated TB cases was respectively 24.1% (95%CI 20.7-27.6) and 58.1% (95%CI 52.1-64.1). More than one third (38.0%) of MDR-TB or rifampicin (RMP) resistant cases showed resistance to either a fluoroquinolone (FQ) or a second-line injectable agent or both. Resistance to pyrazinamide and FQs was low in patients with RMP-susceptible TB. Among new TB cases, the odds of MDR-TB were higher among patients who were younger, female and living in south-eastern provinces, as well as among human immunodeficiency virus-positive patients who belonged to a low socio-economic group. Our study showed that the burden of MDR-TB in Ukraine was much greater than previously assumed. Urgent actions are needed to prevent further spread of drug-resistant TB in Ukraine.

Multidrug-resistant tuberculosis in Queensland, Australia: an ongoing cross-border challenge.

To examine the epidemiology, clinical features and outcomes of MDR-TB in Queensland, with a comparison between cross-border PNG and non-cross-border patients. Retrospective case series of all MDR-TB patients in Queensland between 1 January 2000 and 31 December 2014. Ninety-six patients were diagnosed with MDR-TB in Queensland between 2000 and 2014. The majority were cross-border PNG nationals diagnosed within the Torres Straight Protected Zone (n = 73, 76%). Cross-border patients were younger (27.4 vs. 36.3 years, P = 0.02), had spent less time in Australia before diagnosis (<1 vs. 19 months, P < 0.01), had higher rates of smear positivity (67.1% vs. 40%, P = 0.04) and were less likely to have received a second-line injectable agent (45.8% vs. 71.4%, P = 0.05). Cross-border patients had significantly lower rates of treatment success than non-cross-border patients (47.9% vs. 85.7%; P < 0.01). MDR-TB cases in Queensland are largely a result of cross-border PNG nationals, with poorer outcomes seen in this cohort. Continued strengthening of the region's TB programmes, with a focus on cross-border patients, is required.

Extensively drug-resistant tuberculosis in Myanmar: burden and mutations causing second-line drug resistance.

Two tuberculosis (TB) reference laboratories in Myanmar. To determine the proportion of extensively drug-resistant TB (XDR-TB) cases among multidrug-resistant TB (MDR-TB) cases and the mutations that cause resistance to second-line drugs in Myanmar. This was a cross-sectional, retrospective study. Multidrug-resistant Mycobacterium tuberculosis isolates were collected during 2015-2016. Phenotypic drug susceptibility testing (DST) was performed and drug-resistant mutations identified by sequencing. Genotypes were determined to explain relationships between drug resistance patterns and genotypes. Of 89 MDR-TB isolates, 12 were XDR-TB and 24 were pre-XDR-TB, with 21 resistant to fluoroquinolones (FQs) and 3 to second-line injectable agents (SLIDs). High rates of cross-resistance among second-line drugs were observed. Correlations between phenotypic and molecular DST against FQs and SLIDs were 91% in both cases. The most frequent mutation in FQ-resistant isolates was D94G (8/21) in gyrA and A1401G (11/15) in rrs in those resistant to SLIDs. The dominant genotype was the Beijing type (76/89). There were high proportions of XDR-TB and pre-XDR-TB among MDR-TB cases; cross-resistance among second-line drugs was high, with various types of genetic mutations. These data suggest that resistance to second-line anti-tuberculosis drugs should be monitored intensively, and molecular DST should be employed.

Culture and Next-generation sequencing-based drug susceptibility testing unveil high levels of drug-resistant-TB in Djibouti: results from the first national survey

Djibouti is a small country in the Horn of Africa with a high TB incidence (378/100,000 in 2015). Multidrug-resistant TB (MDR-TB) and resistance to second-line agents have been previously identified in the country but the extent of the problem has yet to be quantified. A national survey was conducted to estimate the proportion of MDR-TB among a representative sample of TB patients. Sputum was tested using XpertMTB/RIF and samples positive for MTB and resistant to rifampicin underwent first line phenotypic susceptibility testing. The TB supranational reference laboratory in Milan, Italy, undertook external quality assurance, genotypic testing based on whole genome and targeted-deep sequencing and phylogenetic studies. 301 new and 66 previously treated TB cases were enrolled. MDR-TB was detected in 34 patients: 4.7% of new and 31% of previously treated cases. Resistance to pyrazinamide, aminoglycosides and capreomycin was detected in 68%, 18% and 29% of MDR-TB strains respectively, while resistance to fluoroquinolones was not detected. Cluster analysis identified transmission of MDR-TB as a critical factor fostering drug resistance in the country. Levels of MDR-TB in Djibouti are among the highest on the African continent. High prevalence of resistance to pyrazinamide and second-line injectable agents have important implications for treatment regimens.

The devil we know: is the use of injectable agents for the treatment of MDR-TB justified?

For decades, second-line injectable agents (IAs) have been the cornerstone of treatment for multidrug-resistant tuberculosis (MDR-TB). Although evidence on the efficacy of IAs is limited, there is an expanding body of evidence on the serious adverse events caused by these drugs. Here, we present the results of a structured literature review of the safety and efficacy of IAs. We review the continued widespread use of these agents in the context of therapeutic alternatives-most notably the newer TB drugs, bedaquiline and delamanid-and from the context of human rights, ethics and patient-centered care. We conclude that there is limited evidence of the efficacy of IAs, clear evidence of the risks of these drugs, and that persons living with MDR-TB should be informed about these risks and provided with access to alternative therapeutic options.

World Health Organization treatment guidelines for drug-resistant tuberculosis, 2016 update.

Antimicrobial resistance is a major global concern. Tuberculosis (TB) strains resistant to rifampicin and other TB medicines challenge patient survival and public health. The World Health Organization (WHO) has published treatment guidelines for drug-resistant TB since 1997 and last updated them in 2016 based on reviews of aggregated and individual patient data from published and unpublished studies. An international expert panel formulated recommendations following the GRADE approach. The new WHO guidelines recommend a standardised 9–12 months shorter treatment regimen as first choice in patients with multidrug- or rifampicin-resistant TB (MDR/RR-TB) strains not resistant to fluoroquinolones or second-line injectable agents; resistance to these two classes of core second-line medicines is rapidly detectable with molecular diagnostics also approved by WHO in 2016. The composition of longer regimens for patients ineligible for the shorter regimen was modified. A first-ever meta-analysis of individual paediatric patient data allowed treatment recommendations for childhood MDR/RR-TB to be made. Delamanid is now also recommended in patients aged 6–17 years. Partial lung resection is a recommended option in MDR/RR-TB care. The 2016 revision highlighted the continued shortage of high-quality evidence and implementation research, and reiterated the need for clinical trials and best-practice studies to improve MDR/RR-TB patient treatment outcomes and strengthen policy.

Drug-resistant tuberculosis in the WHO Western Pacific Region.

To review the latest information about tuberculosis (TB) drug resistance and programmatic management of drug-resistant TB in the Western Pacific Region of the World Health Organization (WHO). We analysed routine data reported by countries to WHO from 2007 to 2013, focusing on data from the following: surveillance and surveys of drug resistance, management of drug-resistant TB and financing related to multidrug-resistant TB (MDR-TB) management. In the Western Pacific Region, 4% (95% confidence interval [CI]: 3-6) of new and 22% (95% CI: 18-26) of previously treated TB cases were estimated to have MDR-TB; this means that in 2013, there were an estimated 71,000 (95% CI: 47,000-94,000) MDR-TB cases among notified pulmonary TB cases in this Region. The coverage of drug susceptibility testing (DST) among new and previously treated TB cases was 3% and 20%, respectively. In 2013, 11,153 cases were notified--16% of the estimated MDR-TB cases. Among the notified cases, 6926 or 62% were enrolled in treatment. Among all enrolled MDR-TB cases, 34% had second-line DST and of these, 13% were resistant to fluoroquinolones (FQ) and/or second-line injectable agents. The 2011 cohort of MDR-TB showed a 52% treatment success. Over the last five years, case notification and enrolment have increased more than five times, but the gap between notification and enrolment widened. The increasing trend in detection and enrolment of MDR-TB cases demonstrates readiness to scale up programmatic management of drug-resistant TB at the country level. However, considerable challenges remain.

Drug-resistant tuberculosis in Eastern Europe: challenges and ways forward.

Encouragingly, global rates of new tuberculosis (TB) cases have been falling since 2005, in line with the Millennium Development Goal targets; however, cases of multidrug-resistant (MDR-) and extensively drug-resistant TB (XDR-TB) have been increasing. Fifteen of the world's 27 high MDR- and XDR-TB burden countries are in the World Health Organization (WHO) European Region, of which 10 are in Eastern Europe (including Baltic and Caucasus countries). To address the MDR- and XDR-TB situation in the WHO European Region, a Consolidated Action Plan to Prevent and Combat M/XDR-TB (2011-2015) was developed for all 53 Member States and implemented in 2011. Since the implementation of the Action Plan, the proportion of MDR-TB appears largely to have levelled off among bacteriologically confirmed TB cases in high-burden countries with universal or near universal (>95%) first-line drug susceptibility testing (DST). The treatment success rate, however, continues to decrease. A contributing factor is the substantial proportion of MDR-TB cases that are additionally resistant to either a fluoroquinolone, a second-line injectable agent or both (XDR-TB); high-burden country proportions range from 12.6% to 80.4%. Proportions of XDR-TB range from 5% to 24.8%. Despite much progress in Eastern Europe, critical challenges remain as regards access to appropriate treatment regimens; patient hospitalisation; scale-up of laboratory capacity, including the use of rapid diagnostics and second-line DST; vulnerable populations; human resources; and financing. Solutions to these challenges are aligned with the Post-2015 Global TB strategy. As a first step, the global strategy should be adapted at regional and country levels to serve as a framework for immediate actions as well as longer-term ways forward.

Triplex real-time PCR melting curve analysis for detecting Mycobacterium tuberculosis mutations associated with resistance to second-line drugs in a single reaction

Resistance to anti-tuberculosis (TB) drugs has been a great challenge for global TB control. Limited tools have been developed to detect resistance to second-line drugs that are associated with extensively drug-resistant (XDR) TB. In this study we aimed to develop a simple and widely applicable assay for detecting mutations associated with second-line drug resistance in Mycobacterium tuberculosis. Three dually labelled probes targeting gyrA, rrs and the promoter of eis were designed to detect resistance to fluoroquinolones and second-line injectable agents (capreomycin, amikacin and kanamycin). A triplex reaction with all three probes and corresponding primers was first tested against 13 isolates with different mutations in the targeted regions. Then, the triplex assay was applied to 109 second-line drug-resistant isolates in a blind manner and the results were compared with the sequencing data. All mutations in the targeted regions of 13 representative isolates could be detected through significant Tm reductions of the corresponding probe compared with the wild-type control. The detection results with 109 isolates were 100% concordant with sequencing data. Twelve ofloxacin-resistant isolates were detected as heteroresistant, indicating the coexistence of mutant and wild-type strains or the existence of different gyrA mutations. We have developed a simple and widely applicable assay to detect second-line drug resistance of M. tuberculosis. This method, combined with assays for detecting first-line drug resistance, provides an efficient and reliable tool to diagnose multidrug-resistant TB and XDR-TB.