Inferring Mycobacterium Tuberculosis Drug Resistance and Transmission using Whole-genome Sequencing in a High TB-burden Setting in China.

Objective: China is among the 30 countries with a high burden of tuberculosis (TB) worldwide, and TB remains a public health concern. Kashgar Prefecture in the southern Xinjiang Autonomous Region is considered as one of the highest TB burden regions in China. However, molecular epidemiological studies of Kashgar are lacking. Methods: A population-based retrospective study was conducted using whole-genome sequencing (WGS) to determine the characteristics of drug resistance and the transmission patterns. Results: A total of 1,668 isolates collected in 2020 were classified into lineages 2 (46.0%), 3 (27.5%), and 4 (26.5%). The drug resistance rates revealed by WGS showed that the top three drugs in terms of the resistance rate were isoniazid (7.4%, 124/1,668), streptomycin (6.0%, 100/1,668), and rifampicin (3.3%, 55/1,668). The rate of rifampicin resistance was 1.8% (23/1,290) in the new cases and 9.4% (32/340) in the previously treated cases. Known resistance mutations were detected more frequently in lineage 2 strains than in lineage 3 or 4 strains, respectively: 18.6% vs. 8.7 or 9%, P < 0.001. The estimated proportion of recent transmissions was 25.9% (432/1,668). Multivariate logistic analyses indicated that sex, age, occupation, lineage, and drug resistance were the risk factors for recent transmission. Despite the low rate of drug resistance, drug-resistant strains had a higher risk of recent transmission than the susceptible strains (adjusted odds ratio, 1.414; 95% CI, 1.023-1.954; P = 0.036). Among all patients with drug-resistant tuberculosis (DR-TB), 78.4% (171/218) were attributed to the transmission of DR-TB strains. Conclusion: Our results suggest that drug-resistant strains are more transmissible than susceptible strains and that transmission is the major driving force of the current DR-TB epidemic in Kashgar.

Epidemiological analysis of registered tuberculosis cases in Kashgar District， Xinjiang Uygur Autonomous Region from 2011 to 2020 / 上海预防医学

ObjectiveTo determine the current status and characteristics of tuberculosis （TB） registration and treatment in Kashgar， and to provide scientific evidence for targeted prevention and control measures in future. MethodsKashgar registered TB cases information in 2011 to 2020 was exported from the National Tuberculosis Management Information System. Descriptive epidemiological analysis was conducted using Stata 12.0. ResultsFrom 2011 to 2020， number of Kashgar registered TB patients showed rising trend， followed by a falling one. Average proportion of annual decline in registered TB incidence was 40.48% from 2018 to 2020. From 2011 to 2016， number of registered TB patients in women was always higher than that in men， with a gender ratio （male ： female） of about 0.90. In 2017， the gender ratio was 1.00. From 2018 to 2020， the gender ratios were 1.05， 1.20， and 1.12， respectively. Moreover， number of registered TB cases increased with age （χ2=547.79， P<0.001）. Proportion of registered TB cases was relatively large in Shache County （16.43%‒23.64%）， Yengisar County （9.51%‒13.87%） ， Kashgar City （8.11%‒11.40%）， Yecheng County （6.98%‒13.40%） and Bachu County（4.92%‒16.65%）. Proportion of recurrent TB cases in Kashgar had increased to 27.29%， 20.77% and 28.39% in 2018， 2019 and 2020， respectively. Multivariate analysis showed that age， drug resistance， calendar year and etiological diagnosis were significantly correlated with the proportion of recurrent cases （all P<0.05）. ConclusionSince 2018， TB incidence has decreased significantly due to the increasing efforts for identification and treatment of TB cases. However， Kashgar remains facing a high TB incidence. TB cases that are elderly， drug-resistant and positive for pathogen are susceptible to recurrent treatment. In future， targeted prevention and control measures should be improved for these groups.

The Epidemiological Characteristics of Pulmonary Tuberculosis - Kashgar Prefecture, Xinjiang Uygur Autonomous Region, China, 2011-2020.

Introduction: National Notifiable Disease Reporting System (NNDRS) plays an important role in the early detection and control of tuberculosis (TB) in China. This study analyzed the epidemiological characteristics of pulmonary tuberculosis (PTB) in Kashgar Prefecture, Xinjiang Uygur Autnomous Region, China from 2011 to 2020 to provide a scientific basis for developing TB control strategies and measures in Kashgar.Methods:The data were collected from the NNDRS, which included the geographical distribution, age, sex, occupation, and pathogenic classification of reported PTB cases in 12 counties/cities of Kashgar Prefecture from 2011 to 2020. Descriptive statistics were used to describe the characteristic of PTB epidemic in Kashgar.Results: There were 189,416 PTB cases reported during 2011-2020, with a mean annual PTB case notification rate (CNR) of 451.29/100,000. A rising trend in the rate of reported PTB between 2011 and 2017 (χ 2 trend=26.09, P<0.01) and a declining trend between 2018 and 2020 (χ 2 trend=314.44, P<0.01) were observed. The months with the highest reported number of PTB cases were March to May and November to December. The mean annual rate of reported PTB was 451.88/100,000 for males and 450.67/100,000 for females. In addition, 19.76% of patients were bacteriologically-confirmed (Bac+) cases (37,425/189,416), and the mean annual Bac+ CNR was 89.17/100,000, rising from 64.76/100,000 in 2011 to 139.12/100,000 in 2020 (χ 2 trend=74.44, P<0.01).Conclusions: The CNR of reported PTB in Kashgar showed a significant declining trend in the past three years. Males, elderly population, winter and spring, and farmers as an occupation were the main factors associated with high incidence of tuberculosis in Kashgar. Targeted prevention and treatment of TB should be strengthened in key groups in this region.