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.

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.