An integrated MDR-TB management programme results in favourable outcomes in northern Taiwan

Primary Bedaquiline Resistance Among Cases of Drug-Resistant Tuberculosis in Taiwan

Bedaquiline (BDQ), which is recommended for the treatment of drug-resistant tuberculosis (DR-TB), was introduced in Taiwan in 2014. Due to the alarming emergence of BDQ resistance, we conducted BDQ resistance analyses to strengthen our DR-TB management program. This retrospective population-based study included initial Mycobacterium tuberculosis isolates from 898 rifampicin-resistant (RR) or multidrug-resistant (MDR) TB cases never exposed to BDQ during 2008-2019. We randomly selected 65 isolates and identified 28 isolates with BDQ MIC<0.25μg/ml and MIC≥0.25μg/ml as the control and study groups, respectively. BDQ drug susceptibility testing (DST) using the MGIT960 system and Sanger sequencing of the atpE, Rv0678, and pepQ genes was conducted. Notably, 18 isolates with BDQ MIC=0.25μg/ml, 38.9% (7/18), and 61.1% (11/18) isolates were MGIT-BDQ resistant and susceptible, respectively. Consequently, we recommended redefining MIC=0.25μg/ml as an intermediate-susceptible category to resolve discordance between different DST methods. Of the 93 isolates, 22 isolates were MGIT-BDQ-resistant and 77.3% (17/22) of MGIT-BDQ-resistant isolates harbored Rv0678 mutations. After excluding 2 MGIT-BDQ-resistant isolates with borderline resistance (GU400growth control-GU100BDQ≤1day), 100% (15/15) harbored Rv0678 gene mutations, including seven novel mutations [g-14a, Ile80Ser (N=2), Phe100Tyr, Ala102Val, Ins g 181-182 frameshift mutation (N=2), Del 11-63 frameshift mutation, and whole gene deletion (N=2)]. Since the other 22.7% (5/22) MGIT-BDQ-resistant isolates with borderline resistance (GU400growth control-GU100BDQ≤1day) had no mutation in three analyzed genes. For isolates with phenotypic MGIT-BDQ borderline resistance, checking for GU differences or conducting genotypic analyses are suggested for ruling out BDQ resistance. In addition, we observed favorable outcomes among patients with BDQ-resistant isolates who received BDQ-containing regimens regardless of Rv0678 mutations. We concluded that based on MIC≥0.25μg/ml, 3.1% (28/898) of drug-resistant TB cases without BDQ exposure showed BDQ resistance, Rv0678 was not a robust marker of BDQ resistance, and its mutations were not associated with treatment outcomes.

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

Background

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

Methods

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

Results

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

Conclusions

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

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

Background

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

Methods

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

Results

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

Conclusions

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

Interventions to improve retention-in-care and treatment adherence among patients with drug-resistant tuberculosis: a systematic review

The global loss to follow-up (LTFU) rate among drug-resistant tuberculosis (DR-TB) patients remains high at 15%. We conducted a systematic review to explore interventions to reduce LTFU during DR-TB treatment.We searched for studies published between January 2000 and December 2017 that provided any form of psychosocial or material support for patients with DR-TB. We estimated point estimates and 95% confidence intervals of the proportion LTFU. We performed subgroup analyses and pooled estimates using an exact binomial likelihood approach.We included 35 DR-TB cohorts from 25 studies, with a pooled proportion LTFU of 17 (12-23)%. Cohorts that received any form of psychosocial or material support had lower LTFU rates than those that received standard care. Psychosocial support throughout treatment, via counselling sessions or home visits, was associated with lower LTFU rates compared to when support was provided through a limited number of visits or not at all.Our review suggests that psychosocial support should be provided throughout DR-TB treatment in order to reduce treatment LTFU. Future studies should explore the potential of providing self-administered therapy complemented with psychosocial support during the continuation phase.

Performance of an Xpert-based diagnostic algorithm for the rapid detection of drug-resistant tuberculosis among high-risk populations in a low-incidence setting

Timely diagnosis of drug-resistant tuberculosis (DR-TB) is beneficial for case treatment and management. We implemented an algorithm to improve molecular diagnostic utilization to intensify DR-TB case findings. The GeneXpert MTB/RIF (Xpert) test was used for initial diagnosis. Samples with Mycobacterium tuberculosis complex (MTBC)-positive and rifampicin resistance (RR) results were subsequently and simultaneously tested using the GenoType MTBDRplus (DRplus) and MTBDRsl (DRsl) tests. This prospective cohort study enrolled 2957 high-risk DR-TB cases. We tested sputum specimens using conventional mycobacteriological and molecular tests. Gene sequencing was performed to resolve discordant results. According to the Xpert test, 33.6% of specimens were MTBC-positive and 5.1% were RR. RR specimens were further analyzed in the DRplus and DRsl tests. We identified 1 extensively drug-resistant (XDR), 8 pre-XDR, 18 simple multidrug-resistant (MDR), 22 mono-RR, and 2 RR cases with concurrent second-line injection DR-TB. Of these, 25 (49%) were relapses, 13 (25.5%) were treatment failures, 10 (19.6%) were from MDR-TB high-incidence areas/countries, 1 was from MDR-TB contact and 2 were unknown. Among culture-positive TB cases, the sensitivities, specificities, and positive predictive values (PPVs) of the Xpert test and RR cases were 73.6% and 100.0%, 85.7% and 98.6%, and 73.5% and 80.0%, respectively. Gene sequencing of discordant results revealed 7 disputed rpoB mutations and 2 silent mutations for RIF, 1 ahpC mutation for isoniazid and 1 gyrA mutation for fluoroquinolone. The algorithm effectively identified approximately 23% of annual MDR-/XDR-TB and 37.5% of RR-TB cases that were enrolled in our DR-TB treatment and management program within 3 days.

Molecular screening of multidrug-resistance tuberculosis by a designated public health laboratory in Taiwan

This manuscript describes our experience in early identifying MDR-TB cases in high-risk populations by setting up a single-referral molecular diagnosis laboratory in Taiwan. Taiwan Centers for Disease Control designated a single-referral laboratory to provide the GenoType MTBDRplus test for screening high-risk MDR-TB populations nationwide in 2012-2015. A total of 5,838 sputum specimens from 3,308 patients were tested within 3 days turnaround time. Compared with the conventional culture and drug susceptibility testing, the overall performance of the GenoType MTBDRplus test for detecting TB infection showed accuracy of 70.7%, sensitivity of 85.9%, specificity of 65.7%, positive predictive value of 45.5%, and negative predictive value of 93.3%. And the accuracy of detecting rifampin (RIF) resistance, isoniazid (INH) resistance, and MDR-TB (resistant to at least RIF and INH) were 96.5%, 95.2%, and 97.7%, respectively. MDR-TB contacts presented a higher rate of mutated codons 513-519, GenoType MTBDRplus banding pattern: rpoB WT3(-), and rpoB WT4(-) than the treatment failure group. The MDR-TB contact group also had a higher rate of inhA C15T mutation, banding pattern: inhA WT1(-), and inhA MUT1(+) than the recurrent group. Resistance profiles of MDR-TB isolates also varied geographically. The referral molecular diagnosis system contributed to rapid detection and initiation of appropriate therapy.

Population-Based Drug Resistance Surveillance of Multidrug-Resistant Tuberculosis in Taiwan, 2007-2014

Objective

To determine the extent of drug resistance in multidrug-resistant tuberculosis (MDR-TB) cases, we conducted a retrospective, population-based analysis using drug susceptibility testing (DST) results of MDR Mycobacterium tuberculosis complex isolates obtained from 2007–2014 in Taiwan.

Methods

M. tuberculosis isolates collected from 1,331 MDR-TB cases were included in this survey. Treatment histories, age, sex, chest radiograph and bacteriological results of patients were analyzed. Standard DST was performed to assess resistance to the following drugs: isoniazid (INH), rifampicin (RIF), streptomycin (SM), ethambutol (EMB), amikacin (AM), kanamycin (KM), capreomycin (CAP), ofloxacin (OFX), moxifloxacin (MOX), levofloxacin (LVX), gatifloxacin (GAT), para-aminosalicylate (PAS), ethionamide (EA), and pyrazinamide (PZA). The Cochran-Armitage trend test was used for statistical analysis.

Results

We observed a significant increasing trend in portion of new MDR-TB cases, from 59.5% to 80.2% (p < 0.0001), and significant decreasing trend of portion in the 15-44-year-old age group (p < 0.05). Of the MDR M. tuberculosis isolates tested, 6.2% were resistant to AM, 8.6% were resistant to KM, 4.6% were resistant to CAP, 19.5% were resistant to OFX, 17.1% were resistant to MOX, 16.0% were resistant to LVX, 5.8% were resistant to GAT, 9.5% were resistant to PAS, 28.5% were resistant to EA and 33.3% were resistant to PZA. Fifty (3.8%) extensively drug-resistant TB cases were identified. No significant differences were found in drug resistance frequencies between new and previously treated MDR cases. However, we observed significant decreases in the rates of AM resistance (p < 0.05), OFX resistance (p < 0.00001), PAS resistance (p < 0.00001), EA resistance (p < 0.05) and PZA resistance (p < 0.05). Moreover, younger age groups had higher rates of resistance to fluoroquinolones.

Conclusion

A policy implemented in 2007 to restrict the prescription of fluoroquinolones was shown to be effective. Our survey revealed a decreasing trend of resistance to PZA, OFX and AM, which suggests the feasibility of adopting a short-course regimen and demonstrates the effectiveness of our management program for MDR-TB.