Multidrug-resistant Rifampicin-resistant Tuberculosis Research Articles

A Transcriptomic Biomarker Predicting Linezolid-Associated Neuropathy During Treatment of Drug-Resistant Tuberculosis.

Neuropathic adverse events occur frequently in linezolid-containing regimens, some of which remain irreversible after drug discontinuation. We aimed to identify and validate a host RNA-based biomarker that can predict linezolid-associated neuropathy before multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) treatment initiation and to identify genes and pathways that are associated with linezolid-associated neuropathy. Adult patients initiating MDR/RR-TB treatment including linezolid were prospectively enrolled in 3 independent cohorts in Germany. Clinical data and whole blood RNA for transcriptomic analysis were collected. The primary outcome was linezolid-associated optic and/or peripheral neuropathy. A random forest algorithm was used for biomarker identification. The biomarker was validated in an additional fourth cohort of patients with MDR/RR-TB from Romania. A total of 52 patients from the 3 identification cohorts received linezolid treatment. Of those, 24 (46.2%) developed peripheral and/or optic neuropathies during linezolid treatment. The majority (59.3%) of the episodes were of moderate (grade 2) severity. In total, the expression of 1,479 genes differed significantly at baseline of treatment. Suprabasin (SBSN) was identified as a potential biomarker to predict linezolid-associated neuropathy. In the validation cohort, 10 of 42 (23.8%) patients developed grade ≥3 neuropathies. The area under the curve for the biomarker algorithm prediction of grade ≥3 neuropathies was 0.63 (poor; 95% confidence interval: 0.42 - 0.84). We identified and preliminarily validated a potential clinical biomarker to predict linezolid-associated neuropathies before the initiation of MDR/RR-TB therapy. Larger studies of the SBSN biomarker in more diverse populations are warranted.

A pragmatic randomized controlled trial to evaluate the efficacy and safety of an oral short-course regimen including bedaquiline for the treatment of patients with multidrug-resistant tuberculosis in China: study protocol for PROSPECT

IntroductionThe lack of safe, effective, and simple short-course regimens (SCRs) for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) treatment has significantly impeded TB control efforts in China.MethodsThis phase 4, randomized, open-label, controlled, non-inferiority trial aims to assess the efficacy and safety of a 9-month all-oral SCR containing bedaquiline (BDQ) versus an all-oral SCR without BDQ for adult MDR-TB patients (18–65 years) in China. The trial design mainly mirrors that of the “Evaluation of a Standardized Treatment Regimen of Anti-Tuberculosis Drugs for Patients with MDR-TB” (STREAM) stage 2 study, while also incorporating programmatic data from South Africa and the 2019 consensus recommendations of Chinese MDR/RR-TB treatment experts. Experimental arm participants will receive a modified STREAM regimen C that replaces three group C drugs, ethambutol (EMB), pyrazinamide (PZA), and prothionamide (PTO), with two group B drugs, linezolid (LZD) and cycloserine (CS), while omitting high-dose isoniazid (INH) for confirmed INH-resistant cases. BDQ duration will be extended from 6 to 9 months for participants with Mycobacterium tuberculosis-positive sputum cultures at week 16. The control arm will receive a modified STREAM regimen B without high-dose INH and injectable kanamycin (KM) that incorporates experimental arm LZD and CS dosages, treatment durations, and administration methods. LZD (600 mg) will be given daily for ≥ 24 weeks as guided by observed benefits and harm. The primary outcome measures the proportion of participants with favorable treatment outcomes at treatment completion (week 40), while the same measurement taken at 48 weeks post-treatment completion is the secondary outcome. Assuming an α = 0.025 significance level (one-sided test), 80% power, 15% non-inferiority margin, and 10% lost to follow-up rate, each arm requires 106 participants (212 total) to demonstrate non-inferiority.DiscussionPROSPECT aims to assess the safety and efficacy of a BDQ-containing SCR MDR-TB treatment at seventeen sites across China, while also providing high-quality data to guide SCRs administration under the direction of the China National Tuberculosis Program for MDR-TB. Additionally, PROSPECT will explore the potential benefits of extending the administration of the 9-month BDQ-containing SCR for participants without sputum conversion by week 16.Trial registrationClinicalTrials.gov NCT05306223. Prospectively registered on 16 March 2022 at https://clinicaltrials.gov/ct2/show/NCT05306223?term=NCT05306223&draw=1&rank=1 {2}.

Tuberculosis multirresistente en Colombia, 2013-2018: estudio de casos y controles

Multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) is difficult to control, has high morbidity and mortality, and demands priority public health intervention. In Colombia, MDR/RR-TB has been becoming more widespread annually. Before the COVID-19 pandemic, over an 8-year period, the number of cases of multidrug-resistant tuberculosis in Colombia was close to a thousand cases. Timely identification of the different risk factors for MDR/RR-TB will contribute fundamentally to the systematic management. To determine which risk factors were associated with the presentation of MDR in Colombia between 2013 and 2018. A retrospective case-control study was carried out, for which the data from the routine surveillance of MDR/events in the country were used. The cases of multidrug-resistant tuberculosis were mainly in young people, Afrodescendants, and males. Of the clinical conditions, comorbidities such as malnutrition, diabetes, and HIV, presence of at least one factor, such as drug dependence, taking immunosuppressive medications, belonging to the black race, afro, and living in an area of high disease burden were risk factors. In addition to the diagnosis and timely provision of MDR-TB treatment, it is necessary that public health programs at the local level pay special attention to patients with the identified risk factors.

Organisation of care for people receiving drug-resistant tuberculosis treatment in South Africa: a mixed methods study

ObjectivesTreatment for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) is increasingly transitioning from hospital-centred to community-based care. A national policy for decentralised programmatic MDR/RR-TB care was adopted in South Africa in 2011. We explored...

The Safety and Tolerability of Linezolid in Novel Short-Course Regimens Containing Bedaquiline, Pretomanid, and Linezolid to Treat Rifampicin-Resistant Tuberculosis: An Individual Patient Data Meta-analysis.

Effectiveness, safety, tolerability, and adherence are critical considerations in shifting to shorter tuberculosis (TB) regimens. Novel 6-month oral regimens that include bedaquiline (B), pretomanid (Pa), and linezolid (L), with or without a fourth drug, have been shown to be as or more effective than the established longer regimens for the treatment of multidrug-resistant/rifampicin-resistant TB (MDR/RR-TB). We aimed to evaluate the safety and tolerability of linezolid in BPaL-containing regimens for the treatment of MDR/RR-TB among recently completed clinical trials. A review and meta-analysis was undertaken including published and unpublished data from clinical trials, conducted between 2010 and 2021, that evaluated regimens containing BPaL for the treatment of MDR/RR-TB. Individual patient data were obtained. For each BPaL-containing regimen, we evaluated the frequency and severity of treatment-related adverse events. The risk difference of adverse events for each regimen was calculated, in comparison to patients assigned to receiving the lowest cumulative exposure of linezolid. Data from 3 clinical trials investigating 8 unique BPaL-containing regimens were included, comprising a total of 591 participants. Adverse events were more frequent in groups randomized to a higher cumulative linezolid dose. Among patients who were randomized to a daily dose of 1200 mg linezolid, 68 of 195 (35%) experienced a grade 3-4 adverse event versus 89 of 396 (22%) patients receiving BPaL-containing regimens containing 600 mg linezolid. Regimens containing BPaL were relatively well tolerated when they included a daily linezolid dose of 600 mg. These novel regimens promise to improve the tolerability of treatment for MDR/RR-TB.

Pregnancy and Birth Outcomes in Patients With Multidrug-Resistant Tuberculosis Treated With Regimens That Include New and Repurposed Drugs.

Among 43 pregnant women receiving multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) treatment with bedaquiline and/or delamanid, 98% had favorable treatment outcomes. Of 31 continued pregnancies, 81% had live births with no reported malformations, and 68% of neonates had normal birth weights. Effective MDR/RR-TB treatment during pregnancy can improve maternal outcomes without harming neonates.

Effect of Stenotrophomonas maltophilia on Tuberculosis.

Tuberculosis (TB) is an important infectious disease suffered by many countries, including China. In this stage, accurate diagnosis and treatment are key measures for the prevention and control of TB. Stenotrophomonas maltophilia is a global emerging Gram-negative, multidrug-resistant (MDR) organism characterized by its high contribution to the increase in crude mortality rates. By single cell preparation and strain identification, we isolated S. maltophilia from stored cultures of Mycobacterium tuberculosis (Mtb). We found that S. maltophilia could not be removed from sputum by alkali treatment or inhibited by antibiotic mixture added to MGIT 960 indicator tubes. When co-cultured with Mtb on a Löwenstein-Jensen (L-J) slant, it could inhibit the growth of Mtb and liquefy the medium. More seriously, it was resistant to 10 of the 12 anti-TB drugs, including isoniazid and rifampin, and made the mixed samples display multidrug-resistant Mtb (MDR-TB) results in the drug sensitivity test, which might change a treatment regimen and increase disease burden. Following, we conducted a small-scale surveillance which showed that the isolation rate of S. maltophilia in TB patients was 6.74%, but these patients had no special characteristics and the presence of S. maltophilia was hidden. The effect of S. maltophilus on TB and its mechanism are unclear and require more attention. IMPORTANCE China is a high-burden country for tuberculosis (TB), multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB), and HIV-associated TB. Increasing the positive rate of culture and the accuracy of antibiotic susceptibility testing (AST) are important for diagnosis, treatment, and control of TB. In our study, we found that the isolation rate of Stenotrophomonas maltophilia in TB patients was not neglectable and that this bacterium affects the isolation and AST results of TB. Due to a lack of relevant research, the impact of S. maltophilia on the course and outcome of TB is unclear. However, the characteristics of S. maltophilia that increase disease mortality require attention. Therefore, in the clinical testing of TB, in addition to mycobacteria, it is recommended to increase the detection of co-infected bacteria and improve the awareness of TB clinicians of these bacteria.

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.

Linezolid-Associated Black Tongue: A Rare Adverse Drug Reaction

Linezolid is an effective second-line anti-tuberculosis drug. However, the use of linezolid has been associated with rare adverse drug reactions (ADRs), one of which is the linezolid-associated black hairy tongue (BHT). This reaction is characterized by a black or dark brown discoloration of the tongue, which may be accompanied by a metallic or bitter taste. In this case report, we present a 19-year-old male patient who developed linezolid-associated black tongue while receiving linezolid as part of an all-oral, longer-course treatment regime for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). The patient's BHT was only cosmetic and resolved upon discontinuation of linezolid. This case report aims to raise awareness of this rare ADR and the importance of close monitoring and potential withdrawal of linezolid to optimize treatment outcomes.

Epidemiology of tuberculosis in the Pacific island countries and areas, 2000-2020.

Tuberculosis (TB) is one of the most important infectious diseases with an estimated 9.9 million people falling ill globally in 2020. We describe the epidemiology of TB in the Pacific island countries and areas (PICs) to inform potential priority actions to implement the Western Pacific Regional Framework to End TB 2021-2030. A descriptive analysis was conducted using annual TB surveillance data submitted by national TB programmes to the World Health Organization (WHO) and TB burden estimates (incidence rates and number of deaths) generated by WHO for the PICs, for the period 2000-2020. We also analysed TB case numbers, multidrug-resistant/rifampicin-resistant TB (MDR/RR-TB), recent risk factor indicators and treatment outcomes. The estimated TB incidence rate in the PICs increased between 2000 and 2020 from 62 to 69 per 100 000 population, with an 8% reduction observed since 2015. TB cases increased by 29% during 2000-2020, with 1746 cases in 2020 and a high proportion in children (19%). Bacteriological diagnosis was used for 58% of total TB cases, although some countries reported clinical diagnoses in over 60% of cases. From 2015 to 2019, 52 MDR/RR-TB cases were reported and there were 94 TB/HIV coinfected cases in 2015-2020. Treatment success was 74% in 2019 due to 18% of cases being unevaluated. In 2020, the estimated proportion of TB cases attributable to smoking, malnutrition, alcohol abuse and diabetes was 17%, 16%, 11% and 9%, respectively. There was an increasing trend in TB cases, estimated incidence and deaths between 2000 and 2020. Laboratory services were scaled up in some PICs and case-finding activities greatly contributed to the detection of cases. To end the incidence of TB, continued efforts on case finding, contact investigation and scaling up TB preventive treatment should be prioritized. At the same time, collaboration with other sectors for risk factor management and decentralized management need to be considered.

Factors affecting time to treatment initiation after diagnosis for multidrug-resistant/rifampicin-resistant tuberculosis patients: A mixed-methods study in Jakarta, Indonesia.

To investigate the time to treatment initiation (TTI) for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) patients after diagnosis in Indonesia and biological, psychological and social factors associated with the time interval. This study was conducted in Persahabatan Hospital, Jakarta using a mixed-methods approach. Registry data and medical records of MDR/RR-TB patients were collected and matched (hospital dataset), and linked with psychosocial assessment results (linked dataset). Descriptive analysis was conducted to understand patient characteristics and the distribution of TTI after RR-TB diagnosis by GeneXpert. Generalised linear regression was used to analyse factors associated with delay duration, and logistic regression to explore factors associated with the delay longer than the median duration for both datasets (basic vs. extended model). In-depth interviews were conducted with patients and healthcare workers to understand the procedure of treatment initiation and how different factors led to delay. The hospital dataset included 275 patient-matched cases, and 188 were further linked with psychosocial assessment results. The median time interval was 24 days [interquartile range (IQR) 23.5] and 26 days (IQR 21.25), respectively. Regression analysis showed that in the extended model, comorbidities (exp [coefficient]= 1.93), unemployment (exp [coefficient]=1.80) and poor knowledge of MDR/RR-TB (exp (coefficient)=1.67) seemed to have the strongest effects on prolonging the time interval (p< 0.05). Unsuccessful TB treatment history was the only factor that significantly increased the risk of delay longer than the median duration (p< 0.05) in the basic model, while none of the factors were significant in the extended model. The qualitative study identified provider-side factors (centralised service provision and insufficient human resources) and patient-side factors (physical weakness, psychological stress and financial concern) associated with treatment delay. MDR/RR-TB patients in Persahabatan Hospital, Jakarta, Indonesia waited around 25 days for treatment initiation after RR-TB diagnosis. Health system solutions are needed to address challenges facing both MDR/RR-TB patients and healthcare providers to reduce delay in treatment initiation.

The Correlations of Minimal Inhibitory Concentration Values of Anti-TB Drugs with Treatment Outcomes and Clinical Profiles in Patients with Multidrug-Resistant Tuberculosis (MDR-TB) in China

ObjectiveIt is a challenge to obtain satisfactory treatment outcomes for patients with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB); the study aims to correlate the Minimum Inhibitory Concentration (MIC) value of drugs with the outcome of patients with MDR/RR-TB to obtain an understanding for better regimens and optimal outcomes.MethodsThe patients diagnosed with MDR/RR-TB were retrospectively enrolled from January 1, 2018 to December 31, 2019, recorded clinical characteristics, MIC DST (Drug Susceptibility Test) results, and followed the treatment outcome. The data were analyzed on the correlations of MIC DST values with outcomes and clinical characteristics.ResultsA total of 276 patients with MDR/RR-TB were included, containing 98 cases (35.5%) with newly treated patients and 178 cases (64.5%) with re-treated patients. A total of 220 cases recorded treatment success (79.7%) and 49 cases recorded treatment failure or died. MIC values of isoniazid (H), moxifloxacin (Mfx), and ethionamide (Eto) in newly treated patients were lower than those in retreated patients, and resistance levels of Mfx and H were closely associated with the treatment outcome (P < 0.05) while those of other drugs had no close association with treatment outcome.ConclusionsMIC values of some anti-TB drugs, such as fluoroquinolones (FQs) and H, can reflect the treatment outcome for patients with MDR/RR-TB, which can contribute to making regimens for better treatment outcomes.

An All-Oral 6-Month Regimen for Multidrug-Resistant Tuberculosis: A Multicenter, Randomized Controlled Clinical Trial (the NExT Study).

Rationale: Improving treatment outcomes while reducing drug toxicity and shortening the treatment duration to ∼6 months remains an aspirational goal for the treatment of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). Objectives: To conduct a multicenter randomized controlled trial in adults with MDR/RR-TB (i.e., without resistance to fluoroquinolones or aminoglycosides). Methods: Participants were randomly assigned (1:1 ratio) to a ∼6-month all-oral regimen that included levofloxacin, bedaquiline, and linezolid, or the standard-of-care (SOC) ⩾9-month World Health Organization (WHO)-approved injectable-based regimen. The primary endpoint was a favorable WHO-defined treatment outcome (which mandates that prespecified drug substitution is counted as an unfavorable outcome) 24 months after treatment initiation. The trial was stopped prematurely when bedaquiline-based therapy became the standard of care in South Africa. Measurements and Main Results: In total, 93 of 111 randomized participants (44 in the comparator arm and 49 in the interventional arm) were included in the modified intention-to-treat analysis; 51 (55%) were HIV coinfected (median CD4 count, 158 cells/ml). Participants in the intervention arm were 2.2 times more likely to experience a favorable 24-month outcome than participants in the SOC arm (51% [25 of 49] vs. 22.7% [10 of 44]; risk ratio, 2.2 [1.2-4.1]; P = 0.006). Toxicity-related drug substitution occurred more frequently in the SOC arm (65.9% [29 of 44] vs. 34.7% [17 of 49]; P = 0.001)], 82.8% (24 of 29) owing to kanamycin (mainly hearing loss; replaced by bedaquiline) in the SOC arm, and 64.7% (11 of 17) owing to linezolid (mainly anemia) in the interventional arm. Adverse event-related treatment discontinuation in the safety population was more common in the SOC arm (56.4% [31 of 55] vs. 32.1% [17 of 56]; P = 0.007). However, grade 3 adverse events were more common in the interventional arm (55.4% [31 of 56] vs. 32.7 [18 of 55]; P = 0.022). Culture conversion was significantly better in the intervention arm (hazard ratio, 2.6 [1.4-4.9]; P = 0.003) after censoring those with bedaquiline replacement in the SOC arm (and this pattern remained consistent after censoring for drug replacement in both arms; P = 0.01). Conclusions: Compared with traditional injectable-containing regimens, an all-oral 6-month levofloxacin, bedaquiline, and linezolid-containing MDR/RR-TB regimen was associated with a significantly improved 24-month WHO-defined treatment outcome (predominantly owing to toxicity-related drug substitution). However, drug toxicity occurred frequently in both arms. These findings inform strategies to develop future regimens for MDR/RR-TB.Clinical trial registered with www.clinicaltrials.gov (NCT02454205).

Strong Increase in Moxifloxacin Resistance Rate among Multidrug-Resistant Mycobacterium tuberculosis Isolates in China, 2007 to 2013.

ABSTRACTWe designed this study to determine the trend of moxifloxacin resistance among multidrug-resistant tuberculosis (MDR-TB) patients from 2007 to 2013 in China to inform the composition of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) treatment regimens. We assessed moxifloxacin resistance among MDR-TB isolates collected in national drug resistance surveys in 2007 and 2013 that included 3,634 smear-positive and 7,206 culture-positive pulmonary tuberculosis patients, respectively. Moxifloxacin susceptibility was examined by a Mycobacterium growth indicator tube (MGIT) 960 for the 2007 isolates, and by the minimum inhibitory concentration (MIC) method for the 2013 isolates, at both breakpoints 0.5 and 2.0 μg/mL. Risk factors were explored through multivariable log-binominal regression analysis. Mutations in gyrA and gyrB for part of the isolates were also studied through sequencing. Of 401 MDR strains isolated in 2007, moxifiloxacin resistance could be determined for 319 (79.6%): 41 (12.9%) and 10 (3.1%) were resistant at 0.5 and 2.0 μg/mL, respectively. Of 365 MDR strains isolated in 2013, 338 (92.6%) could be analyzed: 140 (41.4%) and 79 (23.4%) were resistant at 0.5 and 2.0 μg/mL. For patients in 2007, no characteristics were significantly associated with moxifloxacin resistance. For patients in 2013, patients aged ≥60 years (adjusted prevalence ratio [aPR], 1.46; 95% confidence interval [CI], 1.10 to 1.93) were more likely to have resistance at 0.5 μg/mL, whereas those residing in eastern China compared to those in central China had an increased risk of resistance at both 0.5 (aPR, 1.85; 95% CI, 1.38 to 2.48) and 2.0 μg/mL (aPR, 2.14; 95% CI, 1.35 to 3.40). Sequencing results were obtained for 245 and 266 MDR-TB isolates in 2007 and 2013, respectively. In total, 34 of 38 (89.5%) and 89 of 104 (85.6%) of 2007 and 2013 moxifloxacin-resistant (0.5 μg/mL) MDR-TB strains had mutations in the gyrA and gyrB gene, respectively. Asp94Gly was the most common mutation among 2007 (11 of 38, 28.9%) and 2013 isolates (24 of 104, 23.1%) and conferred high-level moxifloxacin resistance. Moxifloxacin resistance among MDR-TB patients in China increased from modest to high from 2007 to 2013. Moxifloxacin should be used carefully as a potentially effective drug for composing MDR/RR-TB regimens especially for elderly patients in China. Individual susceptibility testing especially rapid molecular-based assays should be conducted to confirm the susceptibility to moxifloxacin.IMPORTANCE China is one of the high-burden countries for multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). Moxifloxacin is one of the critical antituberculosis drugs for MDR/RR-TB treatment. Susceptibility to moxifloxacin is therefore very important to compose effective regimens and to provide protection against development of resistance of companion drugs such as bedaquiline and linezolid. There are, however, no nationally representative data on moxifloxacin resistance among MDR/RR-TB cases in China. Therefore, we assessed the resistance prevalence for moxifloxacin among MDR-TB strains isolated in national drug resistance surveys in 2007 and 2013 that covered 72 sites around the country. We demonstrate that the prevalence of moxifloxacin resistance in MDR-TB isolates increased from modest to high, which should prompt the national tuberculosis program to use moxifloxacin cautiously in second-line regimens to treat MDR/RR-TB unless susceptibility can be laboratory-confirmed.

Scaling Up Molecular Diagnostic Tests for Drug-Resistant Tuberculosis in Uzbekistan from 2012-2019: Are We on the Right Track?

Uzbekistan has a large burden of drug-resistant tuberculosis (TB). To deal with this public health threat, the National TB Program introduced rapid molecular diagnostic tests such as Xpert MTB/RIF (Xpert) and line probe assays (LPAs) for first-line and second-line drugs. We documented the scale-up of Xpert and LPAs from 2012–2019 and assessed whether this led to an increase in patients with laboratory-confirmed multidrug-resistant/rifampicin-resistant TB (MDR/RR-TB) and extensively drug-resistant TB (XDR-TB). This was a descriptive study using secondary program data. The numbers of GeneXpert instruments cumulatively increased from six to sixty-seven, resulting in annual assays increasing from 5574 to 107,330. A broader use of the technology resulted in a lower proportion of tests detecting Mycobacterium tuberculosis with half of the positive results showing rifampicin resistance. LPA instruments cumulatively increased from two to thirteen; the annual first-line assays for MDR-TB increased from 2582 to 6607 while second-line assays increased from 1435 in 2016 to 6815 in 2019 with about one quarter to one third of diagnosed patients showing second-line drug resistance. Patient numbers with laboratory-confirmed MDR-TB remained stable (from 1728 to 2060) but there was a large increase in patients with laboratory-confirmed XDR-TB (from 31 to 696). Programmatic implications and ways forward are discussed.

Design of Multidrug-Resistant Tuberculosis Treatment Regimens Based on DNA Sequencing.

Comprehensive and reliable drug susceptibility testing (DST) is urgently needed to provide adequate treatment regimens for patients with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). We determined whether next-generation sequencing (NGS) analysis of Mycobacterium tuberculosis complex isolates and genes implicated in drug resistance can guide the design of effective MDR/RR-TB treatment regimens. NGS-based genomic DST predictions of M. tuberculosis complex isolates from MDR/RR-TB patients admitted to a TB reference center in Germany between 1 January 2015 and 30 April 2019 were compared with phenotypic DST results of mycobacteria growth indicator tubes (MGIT). Standardized treatment algorithms were applied to design individualized therapies based on either genomic or phenotypic DST results, and discrepancies were further evaluated by determination of minimal inhibitory drug concentrations (MICs) using Sensititre MYCOTBI and UKMYC microtiter plates. In 70 patients with MDR/RR-TB, agreement among 1048 pairwise comparisons of genomic and phenotypic DST was 86.3%; 76 (7.2%) results were discordant, and 68 (6.5%) could not be evaluated due to the presence of polymorphisms with yet unknown implications for drug resistance. Importantly, 549 of 561 (97.9%) predictions of drug susceptibility were phenotypically confirmed in MGIT, and 27 of 64 (42.2%) false-positive results were linked to previously described mutations mediating a low or moderate MIC increase. Virtually all drugs (99.0%) used in combination therapies that were inferred from genomic DST were confirmed to be susceptible by phenotypic DST. NGS-based genomic DST can reliably guide the design of effective MDR/RR-TB treatment regimens.

Factors associated with time to sputum culture conversion of rifampicin-resistant tuberculosis patients in Klaipeda, Lithuania in 2016-2019: a cohort study.

The global proportion of successful treatment outcomes of Multidrug-Resistant/Rifampicin-Resistant Tuberculosis (MDR/RR-TB) remains unacceptably low. Time to culture conversion is important in making treatment-related decisions and is used as an interim predictor of pulmonary MDR/RR-TB treatment success. No previous studies have been conducted to assess determinants of time to culture conversion for MDR/RR-TB patients in Lithuania. Secondary analysis of data of culture-positive MDR/RR-TB patients, treated in Republican Klaipeda Hospital between 1st July 2016 and 1st July 2019 was performed. Culture conversion was defined as two consecutive negative cultures on solid media submitted at least 30 days apart. Factors associated with culture conversion were estimated by crude and multivariable Cox regression accounting for competing risks.In total, 115 consecutive patients starting treatment were included in the study. Of them, the majority was male (86/115; 74.8%) with a mean age of 48 (standard deviation (SD) ±12) years and Human Immunodeficiency Virus (HIV) negative (105/115; 91.3%). Nearly two-thirds (72/115; 62.6%) had XDR (extensive drug resistance) or MDR/RR-TB with additional resistance to second-line injectables or fluoroquinolones. Of 115 culture-positive patients at baseline, 103 (89.6%) patients achieved culture conversion during 12 months of treatment. The median time to culture conversion was 1.1 months (interquartile range: 0.9-1.8). Patients aged ≥60 years compared with <40 years [adjusted hazard ration (aHR): 0.40, 95% confidence interval (CI): 0.18-0.86], smokers (aHR: 0.39, 95% CI: 0.2-0.73), patients with positive sputum smear microscopy at baseline (aHR: 0.40, 95% CI: 0.25-0.63), cavities on initial chest X-ray (aHR: 0.56, 95% CI: 0.35-0.88) and resistance to at least one fluoroquinolone drug (aHR: 0.52, 95% CI: 0.32-0.84) were slower to culture convert. In conclusion, we recommend providing additional counseling, treatment adherence interventions and scale up the use of new and repurposed TB drugs to patient groups at risk of worse interim treatment outcome: patients aged 60 and above, with resistance to fluoroquinolones, smear-positive, smokers, or with signs of extensive disease evident on initial chest radiography.

Outcome of community-initiated treatment of drug-resistant tuberculosis patients in Lagos, Nigeria.

BackgroundWith the improvement in the capacity to diagnose multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) patients due to the increased number of GeneXpert machines in Nigeria, the number of patients diagnosed surpassed the bed capacity at MDR-TB treatment centres. Community DR-TB treatment is an important option to improve access to care for MDR/RR-TB patients. However, few studies have determined the outcome of community management of MDR-TB patients, which this study aims to address.MethodsWe conducted a retrospective study of MDR/RR-TB patients initiated on treatment in the community in Lagos, Nigeria, between 1 January 2015 and 31 December 2016. Data were retrieved from DR-TB treatment cards/registers. The treatment outcomes of these patients were assessed at the end of treatment and categorized according to national TB guidelines.ResultsA total of 150 DR-TB patients commenced treatment during the study period. Adherence was 64.7%, with the majority of patients experiencing mild (56.5%) adverse drug events. Treatment was successful in 70% of patients. The only predictor of successful treatment was treatment adherence.ConclusionsThe study shows that community initiation of MDR-TB treatment is feasible and results in a high treatment success rate. Adherence counselling before and during treatment is essential for a favourable treatment outcome.

An All-Oral 6-Month Regimen for Multi-Drug Resistant/Rifampicin-Resistant Tuberculosis: A Multi-Centre, Phase 3, Open Label, Randomised Controlled Trial (NeXT Study)

Background: Improving treatment outcomes, reducing drug toxicity, eliminating the need for injectable agents, and shortening the treatment duration to 6-months (the same as rifampicin-susceptible tuberculosis) remains an aspirational goal for the treatment of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB). Methods: We conducted a multicentre randomised controlled trial in adults with MDR/RR-TB (i.e. without resistance to fluoroquinolones or aminoglycosides). Participants were randomly assigned (1:1 ratio) to a 6-month all-oral regimen that included levofloxacin, bedaquiline and linezolid, or the standard-of-care ≥ 9-month WHO-approved injectable-based regimen. The primary endpoint was a favourable WHO-defined treatment outcome 24 months after treatment initiation. Findings: 93 of 111 participants randomised were included in the modified intention-to-treat analysis; 51 (55%) were HIV co-infected (median CD4 count 158 cells/ml). Participants in the intervention arm were 2·2 times more likely to experience a favourable 24-month outcome ( 95% CI) than participants in the standard-of-care arm [RR 2·2 (1·2–4·1); p=0·006]. They were also less likely, over a 24-month period, to experience an unfavourable outcome event than participants in the standard-of-care arm [HR 0·4, (0·2–0·6), p<0·001]. Toxicity-related drug substitution occurred more frequently in the standard-of-care arm [(65·9% (29/44) versus 36·7% (18/49), p= 0·001)]; 79.3% (23/29) due to kanamycin (mainly hearing loss; replaced by bedaquiline) in the standard-of-care arm, and 83·3% (15/18) due to linezolid (mainly anaemia) in the interventional arm. Time to culture conversion was significantly better in the interventional arm [HR 2·6 (1·4–4·9); p= 0·003] after censoring those with bedaquiline replacement in the standard-of-care arm. Interpretation: An all-oral 6-month levofloxacin, bedaquiline and linezolid-containing MDR/RR-TB regimen was associated with significantly improved 24-month treatment outcomes compared with traditional injectable-containing regimens. However, drug toxicity occurred frequently in both arms. These findings inform strategies to develop future regimens for MDR/RR-TB. Trial Registration: The trial was registered on clinicaltrials.gov (NCT02454205). Funding: South African MRC, Pfizer, and the European and Developing Country Clinical Trial Partnership (EDCTP) Declaration of Interest: None to declare. Ethical Approval: An institutional review board or ethics committee at each participating trial site reviewed and approved the protocol and informed consent documents.

Effect of reliance on Xpert MTB/RIF on time to treatment and multidrug-resistant tuberculosis treatment outcomes in Tanzania: a retrospective cohort study.

During 2009-2013, Xpert MTB/RIF testing was decentralized in Tanzania. Standardized treatment of multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB) was centralized at the Kibong'oto Infectious Diseases Hospital. Initially, Xpert MTB/RIF results were confirmed and complemented with phenotypic drug susceptibility testing before MDR-TB treatment was started. Since 2013, the decision to start MDR-TB treatment in patients with RR-TB relied on Xpert MTB/RIF results. A retrospective cohort study of predictors of unsuccessful treatment outcomes (including death, lost to follow-up and treatment failure) was carried out. During the study period, 201 patients started MDR-TB treatment. The number of patients starting MDR-TB treatment increased over time. Out of 201 patients, 48 (23.9%) had an unsuccessful treatment outcome. The median time between sample collection and MDR-TB treatment initiation was reduced from 155 d (IQR 40-228) in the 2009-2012 period to 26 d (IQR 13-64) in 2013. Patients who started MDR-TB treatment in 2013 were more likely (adjusted OR 2.3; 95% CI 1.1-4.7; p=0.02) to have an unsuccessful treatment outcome. Xpert MTB/RIF testing increased enrolment on MDR-TB treatment. Reliance on Xpert MTB/RIF results to start MDR-TB treatment reduced time to treatment. However, treatment outcomes did not improve.