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

Study of fluoroquinolones resistance in rifampicin-resistant tuberculosis patients in Beijing: Characteristics, trends, and treatment outcomes

BACKGROUND

China is a high-burden country for multidrug-resistant tuberculosis/rifampin-resistant tuberculosis (MDR/RR-TB). Fluoroquinolones (FQs) are key drugs for the treatment of patients with MDR/RR-TB. However, research on the resistance of FQs in Beijing is limited.

METHODS

We collected clinical isolates from all patients with pulmonary TB in Beijing from January 2016 to December 2021, conducted drug-sensitivity tests and sequencing for levofloxacin (LFX) and moxifloxacin (MFX), and collected the treatment plans and outcomes of the patients.

RESULTS

A total of 8512 clinical isolates were collected from patients with pulmonary TB, and 261 RR-TB strains were screened. The proportions of drug-sensitive and drug-resistant strains significantly differed by age group and treatment history. The rates of LFX and MFX resistance were 27.6% (72/261) and 36.4% (95/261), respectively. The detection rates of MDR-TB and pre-extensively drug-resistant TB (pre-XDR-TB) were 73.2% (191/261) and 36.4% (95/261), respectively, and the trends were significant (χ2 trend = 9.995, p = 0.002; χ2 trend = 12.744, p = 0.026). Among the 261 RR-TB strains, 14.9% (24/261) were sensitive to LFX but resistant to MFX. Among the four patients with LFX-resistant TB who received LFX treatment failed in three patients(Fisher's exact test, p = 0.009). The common mutation sites were 94 and 90 in gyrA. A novel mutation Ala90Ser was discovered.

CONCLUSIONS

FQs resistance trends in RR-TB patients in Beijing are striking. Strains showed incomplete cross-resistance to LFX and MFX. Testing for FQs resistance and developing a reasonable treatment plan are recommended. Attention should be given to the changing trends in MDR-TB and pre-XDR-TB.

Multidrug-resistant tuberculosis clusters and transmission in Taiwan: a population-based cohort study

Introduction

Multidrug-resistant tuberculosis (MDR-TB) remains a challenge in the TB program of Taiwan, where 0.5% of new cases and 2.1% of previously treated cases were resistant to at least rifampin (RIF) and isoniazid (INH). Since >80% of our MDR-TB are new cases, genotyping of MDR Mycobacterium tuberculosis is implemented to facilitate contact investigation, cluster identification, and outbreak delineation.

Methods

This is a population-based retrospective cohort study analyzing MDR-TB cases from 2019 to 2022. Whole genome sequencing (WGS) was performed using the Illumina MiSeq and analyzed using the TB Profiler. A single nucleotide polymorphism (SNP) threshold of ≤ 12 and phylogenetic methods were used to identify putative transmission clusters. An outbreak was confirmed using genomic data and epidemiologic links.

Results

Of the 297 MDR-TB cases, 246 (82.8%), 45 (15.2%), and 6 (2.0%) were simple MDR, extensively drug-resistant tuberculosis (pre-XDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), respectively. The sublineage 2.2 modern Beijing was the predominant (48.8%) MDR-TB strain in Taiwan. Phylogenetic analysis identified 25.3% isolates in 20 clusters, with cluster sizes ranging from 2 to 13 isolates. Nevertheless, only 2 clusters, one household and one community, were confirmed as outbreaks. In this study, we found that males had a higher risk of MDR-TB transmission compared to females, and those infected with the sublineage 2.1-proto-Beijing genotype isolates were at a higher risk of transmission. Furthermore, 161 (54.2%) isolates harbored compensatory mutations in the rpoC and non-rifampicin resistant determinant region (non-RRDR) of the rpoB gene. MDR-TB strains containing rpoB S450L and other compensatory mutations concurrently were significantly associated with clusters, especially the proto-Beijing genotype strains with the compensatory mutation rpoC E750D or the modern Beijing genotype strains with rpoC D485Y/rpoC E1140D.

Discussion

Routine and continuous surveillance using WGS-based analysis is recommended to warn of risks and delineate transmission clusters of MDR-TB. We proposed the use of compensatory mutations as epidemiological markers of M. tuberculosis to interrupt putative MDR-TB transmission.

Mitigating treatment failure of pulmonary pre-extensively drug-resistant tuberculosis: The role of new and repurposed drugs

BACKGROUND

Pre-extensively drug-resistant tuberculosis (pre-XDR-TB), defined as multidrug-resistant TB (MDR-TB) with additional resistance to any fluoroquinolone (FQ) is difficult to treat. We assessed whether the use of new or repurposed drugs (bedaquiline, delamanid, linezolid, carbapenem, clofazimine, pretomanid) mitigated treatment failure of pre-XDR-TB.

METHODS

MDR-TB patients managed in the Taiwan MDR-TB consortium between July 2009-December 2019 were eligible. Treatment outcomes at 30 months were assessed. Logistic regression models were constructed to investigate factors associated with treatment outcomes.

RESULTS

109 patients with FQ-resistant MDR-TB and 218 patients with FQ-susceptible MDR-TB were included. 60 (55.1%) patients with FQ-resistant MDR-TB and 63 (28.9%) patients with FQ-susceptible MDR-TB have been treated with new or repurposed drugs (p < 0.01). Of the 218 patients with FQ-susceptible MDR-TB, 187 (85.8%) had treatment success, 30 (13.8%) died, no treatment failure, and 1 (0.5%) was loss-to-follow-up; of the 109 patients with FQ-resistant MDR-TB, 78 (71.6%) had treatment success, 21 (19.3%) died, 9 (8.3%) had treatment failure, and 1 (0.9%) was loss-to-follow-up (p < 0.01). The use of new or repurposed drugs was not associated with treatment outcomes among patients with FQ-susceptible MDR-TB. No patients with FQ-resistant MDR-TB treated with ≥2 new or repurposed drugs within 6 months of treatment initiation had treatment failure (p = 0.03). Patients with FQ-resistant MDR-TB treated with 1 new or repurposed drugs was more likely to have treatment failure as compared with patients not treated with new or repurposed drugs (adjOR 7.06, 95% CI 1.72-29.06).

CONCLUSIONS

Proper use of new or repurposed anti-TB drugs can mitigate treatment failure in FQ-resistant MDR-TB.

Global status of phenotypic pyrazinamide resistance in Mycobacterium tuberculosis clinical isolates: an updated systematic review and meta-analysis

Pyrazinamide (PZA) is an essential first-line tuberculosis drug for its unique mechanism of action active against multidrug-resistant-TB (MDR-TB). Thus, the aim of updated meta-analysis was to estimate the PZA weighted pooled resistance (WPR) rate in M. tuberculosis isolates based on publication date and WHO regions. We systematically searched the related reports in PubMed, Scopus, and Embase (from January 2015 to July 2022). Statistical analyses were performed using STATA software. The 115 final reports in the analysis investigated phenotypic PZA resistance data. The WPR of PZA was 57% (95% CI 48-65%) in MDR-TB cases. According to the WHO regions, the higher WPRs of PZA were reported in the Western Pacific (32%; 95% CI 18-46%), South East Asian region (37%; 95% CI 31-43%), and the Eastern Mediterranean (78%; 95% CI 54-95%) among any-TB patients, high risk of MDR-TB patients, and MDR-TB patients, respectively. A negligible increase in the rate of PZA resistance were showed in MDR-TB cases (55% to 58%). The rate of PZA resistance has been rising in recent years among MDR-TB cases, underlines the essential for both standard and novel drug regimens development.

Surveillance of multidrug-resistant tuberculosis in Taiwan, 2008-2019

BACKGROUND

Drug-resistant tuberculosis (DR-TB) is a major contributor to global cases of antimicrobial resistance and remains a public health challenge. To understand the extent and trend of DR-TB under an enhanced multidrug-resistant TB (MDR-TB) management program, we conducted a population-based retrospective study of 1511 Taiwanese MDR-TB cases reported from 2008 to 2019.

METHODS

We obtained patient demographics and clinical and bacteriological information from the National TB Registry and the Infectious Disease Notification System.

RESULTS

Of the 1511 MDR-TB patients, 941 were new cases, 485 were previously treated, and 85 had an unknown history of treatment. The male to female ratio was 2.75, and the median age of the patients was 57 years (IQR: 45-72). We observed a significant decline in MDR-TB cases, with annual percentage change (APC) of -4.17%. However, new and previously treated MDR-TB cases had APCs of -1.41% and -9.18%, respectively. The rates of MDR-TB resistance to ethambutol, streptomycin and pyrazinamide were 47.2%, 42.4% and 28.9%, respectively, whereas the rates of resistance to fluoroquinolones and second-line injectable drugs (SLIDs) were 4.1-7.1%, 9.0-14.1%; and the rate of extensively drug-resistant TB was 1.9%, respectively. Furthermore, we observed a decreasing trend of resistance to SLIDs (APCs -7.0% to -8.2%) in new cases and a significant decreasing trend of resistance to moxifloxacin (-24.6%) and levofloxacin (-23.3%) in previously treated cases.

CONCLUSION

The decreasing trend of MDR-TB and resistance to second-line drugs suggested that our programmatic management of TB was effective and that the impact on TB control was profound.

Regional distribution of Mycobacterium tuberculosis infection and resistance to rifampicin and isoniazid as determined by high-resolution melt analysis

Background

Identifying the transmission mode and resistance mechanism of Mycobacterium tuberculosis (MTB) is key to prevent disease transmission. However, there is a lack of regional data. Therefore, the aim of this study was to identify risk factors associated with the transmission of MTB and regional patterns of resistance to isoniazid (INH) and rifampicin (RFP), as well as the prevalence of multidrug-resistant tuberculosis (MDR-TB).

Methods

High-resolution melt (HRM) analysis was conducted using sputum, alveolar lavage fluid, and pleural fluid samples collected from 17,515 patients with suspected or confirmed MTB infection in the downtown area and nine counties of Luoyang City from 2019 to 2021.

Results

Of the 17,515 patients, 82.6% resided in rural areas, and 96.0% appeared for an initial screening. The HRM positivity rate was 16.8%, with a higher rate in males than females (18.0% vs. 14.1%, p < 0.001). As expected, a positive sputum smear was correlated with a positive result for HRM analysis. By age, the highest rates of MTB infection occurred in males (22.9%) aged 26–30 years and females (28.1%) aged 21–25. The rates of resistance to RFP and INH and the incidence of MDR were higher in males than females (20.5% vs. 16.1%, p < 0.001, 15.9% vs. 12.0%, p < 0.001 and 12.9% vs. 10.2%, p < 0.001, respectively). The HRM positivity rate was much higher in previously treated patients than those newly diagnosed for MTB infection. Notably, males at the initial screening had significantly higher rates of HRM positive, INH resistance, RFP resistance, and MDR-TB than females (all, p < 0.05), but not those previously treated for MTB infection. The HRM positivity and drug resistance rates were much higher in the urban vs. rural population. By multivariate analyses, previous treatment, age < 51 years, residing in an urban area, and male sex were significantly and positively associated with drug resistance after adjusting for smear results and year of testing.

Conclusion

Males were at higher risks for MTB infection and drug resistance, while a younger age was associated with MTB infection, resistance to INH and RFP, and MDR-TB. Further comprehensive monitoring of resistance patterns is needed to control the spread of MTB infection and manage drug resistance locally.

Epidemiological and laboratory characteristics of multidrug-resistant tuberculosis patients in Bhutan, 2015-2019

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Multidrug-resistant tuberculosis (MDR-TB) reported in high numbers of new TB cases

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Majority of MDR-TB patients in the economically productive age group

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No major variations in mutation pattern for Line Probe Assay results across 5 years

Background

Bhutan is no exception to the rising global threat of drug resistance tuberculosis (TB), particularly multidrug-resistant (MDR) TB. Although drug resistance surveillance has been carried out in Bhutan since 2010, limited analysis reports are available. Therefore, we looked at data from 2015−2019 to understand patient characteristics.

Method

To obtain data for MDR-TB from the past 5 years, we looked at manual registers and laboratory worksheets for all samples received at National TB Reference Laboratory. Epidemiological factors and laboratory variables were analyzed using descriptive statistics.

Result

Among 304 patients with MDR-TB, 85.20% (n=259) are new cases with no previous history of treatment. Those aged 16−25 years from both genders are affected more (46.05%, n=140) than other age groups. The majority (94.62%, n=264) of rifampicin resistance was found in the MUT 3 rpoB gene. For Isoniazid, 97.13% (n=271) resistance was seen in the MUT1 band of the katG gene.

Conclusion

A high number of MDR-TB cases among new patients and little variation in the resistance band pattern over 5 years could indicate uncontrolled ongoing transmission. Whole-genome sequencing for the samples is required to further understand the epidemiology of the resistance pattern.

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

We 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.

Primary Drug-Resistance Pattern and Trend in Elderly Tuberculosis Patients in Shandong, China, from 2004 to 2019

BACKGROUND

With an aging population, China is facing a huge burden of elderly patients with drug resistant tuberculosis (DR-TB), which has become a significant obstacle for the global TB control. There is still little study on DR-TB in the elderly in China so far. Thus, more research on the epidemiological characteristics and trend of primary DR-TB among the elderly will be necessary.

METHODS

A retrospective study was conducted in Shandong, China from 2004 to 2019. We collected 12,661 primary TB cases, of which 4368 elderly (≥60 years) primary TB cases were involved. Clinical characteristics including age, sex, cavity, smoking, drinking, comorbidity and drug susceptibility data were collected from 36 TB prevention and control institutions of Shandong Province. Sputum samples were collected by each surveillance site, and examined in the TB Reference Laboratory of SPCH. Descriptive statistical analysis, chi-square and linear regression were used for analyzing.

RESULTS

Among 4368 elderly patients with primary TB, the DR-TB and multi-resistant tuberculosis (MDR-TB) accounted for 17.19% and 2.29%, respectively. During 2004-2019, the proportions of MDR-TB, polydrug resistant tuberculosis (PDR-TB), rifampin (RFP)-resistance increased by 160.00%, 18.18%, 231.82%, respectively and the rate of DR-TB among elderly patients with primary cavitary TB increased by 255%. Among the elderly with primary DR-TB during 2004-2019, the proportion of male (from 85.19 to 89.06), cavity (from 7.41 to 46.88), RFP-resistance (from 3.70 to 21.88), and streptomycin (SM)-resistance (from 37.04 to 62.5) increased significantly (P<0.05). And the proportion of female (from 14.81 to 10.94), non-cavity (from 92.59 to 32.81), INH-resistance (from 66.67 to 57.81) decreased significantly (P<0.05).

CONCLUSION

Among the elderly, the proportions of MDR-TB, PDR-TB, RFP-resistance and cavitary DR-TB increased significantly. The pattern of DR-TB changed from female, non-cavity and INH-resistant groups to male, cavity, RFP or SM-resistant groups. For a better control on the elderly DR-TB in the future, we should pay more attention to male, smoking, drinking, chronic obstructive pulmonary disease (COPD) and diabetes subgroups and take targeted measures to control these subgroups.

Genomic Analysis of Mycobacterium tuberculosis Isolates and Construction of a Beijing Lineage Reference Genome

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis, kills over 1 million people worldwide annually. Development of drug resistance (DR) in the pathogen is a major challenge for TB control. We conducted whole-genome analysis of seven Taiwan M. tuberculosis isolates: One drug susceptible (DS) and five DR Beijing lineage isolates and one DR Euro-American lineage isolate. Developing a new method for DR mutation identification and applying it to the next-generation sequencing (NGS) data from the 6 Beijing lineage isolates, we identified 13 known and 6 candidate DR mutations and provided experimental support for 4 of them. We assembled the genomes of one DS and two DR Beijing lineage isolates and the Euro-American lineage isolate using NGS data. Moreover, using both PacBio and NGS sequencing data, we obtained a high-quality assembly of an extensive DR Beijing lineage isolate. Comparative analysis of these five newly assembled genomes and two published complete genomes revealed a large number of genetic changes, including gene gains and losses, indels and translocations, suggesting rapid evolution of M. tuberculosis. We found the MazEF toxin-antitoxin system in all the seven isolates studied and several interesting mutations in MazEF proteins. Finally, we used the four assembled Beijing lineage genomes to construct a high-quality Beijing lineage reference genome that is DS and contains all the genes in the four genomes. It contains 212 genes not found in the standard reference H37Rv, which is Euro-American. It is therefore a better reference than H37Rv for the Beijing lineage, the predominant lineage in Asia.

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.

Development of a high sensitivity TaqMan-based PCR assay for the specific detection of Mycobacterium tuberculosis complex in both pulmonary and extrapulmonary specimens

Tuberculosis (TB) causes a heavy health burden worldwide, especially in developing countries. The need for the rapid and accurate diagnosis of TB has not been satisfied, especially for extra-pulmonary specimens or specimens with acid fast stain (AFS)-negative condition. Development and validation of a novel, sensitive and specific assay for diagnosing TB is essential. We developed IS4 primer/probe based on insertion sequence 6110 (IS6110). A qPCR assay was designed for detecting a specific region in IS6110 by BLAST. The IS4 primer/probe concentration, qPCR efficiency and various of PCR additives were evaluated and optimized. Thirty-four species of commonly isolated microorganisms were used for evaluating the analytical specificity. Moreover, 130 clinical specimens were collected for evaluating the performance versus Cobas TaqMan MTB (CTM) assay kit and culture. The amplification efficiencies of IS4 were 99.61% and 102.61% without and with internal control DNA (Bacteriophage Lambda), respectively. Dimethyl sulfoxide outperformed glycerol or BSA for eliciting the most effective amplification and the lowest limit of detection. In evaluating the clinical performance, various specimen types were collected. IS4 demonstrated a high degree of agreement (kappa = 0.71) with CTM. The clinical sensitivity and specificity of IS4 and CTM were 92.11% (35/38), 82.61% (76/92), 84.21% (32/38) and 95.65% (88/92), respectively. The clinical sensitivity and specificity of IS4 were similar for both pulmonary [92.00% (23/25) and 76.92% (30/39), respectively] and extrapulmonary [92.31% (12/13) and 86.79% (46/53), respectively] specimens. Among AFS-negative cases, the clinical sensitivity and specificity remained 90.48% (19/21) and 83.91% (73/87), respectively, with culture as the gold standard. We concluded that IS4, a new primer/probe pair for TaqMan based qPCR assay, was developed, optimized, and validated for the sensitive and specific detection of TB among various specimen types. The performance was not compromised under AFS-negative conditions.

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.