Tuberculosis (TB), a persistent global health threat (1), caused an estimated 1.25 million deaths in 2023, surpassing COVID-19 as the leading infectious disease killer (1, 2). While global TB incidence rates declined by 2% annually from 2010 to 2020, recent years have seen a resurgence, with 10.8 million new cases projected for 2023—a 4.6% increase from 2020 levels (3). Drug-resistant TB (DR-TB), particularly multidrug-resistant TB (MDR-TB), compounds this crisis. In 2023, 400,000 new MDR/rifampicin-resistant TB (RR-TB) cases emerged globally, yet only 44% were diagnosed and treated, with treatment success rates stagnating below 70% (3). MDR-TB’s prolonged treatment duration, high costs, and socioeconomic burden underscore the urgent need for targeted interventions (4, 5).

In recent years, Wenzhou City has implemented several measures to control MDR-TB, including expanding phenotypic drug sensitivity testing (pDST) to most bacteriologically positive patients, equipping all designated TB hospitals with the GeneXpert MTB/RIF system for rapid rifampicin resistance detection, incorporating MDR pulmonary TB into medical insurance with subsidies up to 30,000 yuan per patient, and increasing financial support for designated TB hospitals. These efforts have improved local MDR-TB control, but challenges remain in providing TB services to vulnerable populations, such as migrants (6).

In the context of rapid social and economic development in China, population movements have become increasingly frequent (7). As an economically developed coastal city, Wenzhou has attracted a significant number of migrants. The living conditions of this migrant population are often complex, characterized by overcrowding and inadequate sanitation facilities, which facilitate the spread of MDR-TB (8). Additionally, previous studies (9, 10) have indicated that the frequent relocation of migrants can lead to challenges in accessing medical care across different regions, resulting in interrupted treatment and irregular medication adherence. This situation increases the likelihood of developing MDR-TB among the migrant population. Understanding the epidemiological characteristics and trends of MDR-TB within this group is therefore essential for the timely detection and management of mobile patients and for effective epidemic control. To date, such evidence has been lacking for Wenzhou. This study aims to analyze the epidemiological features and temporal trends of MDR-TB among notified TB cases in Wenzhou from 2014 to 2023 and to compare patterns between migrant and local populations, so as to inform the development of targeted prevention and control strategies.

The results of this study indicate that the overall proportion of MDR among notified TB cases in Wenzhou City from 2014 to 2023 was 6.68%, which decreased to 5.06% in 2023. A study conducted by Yao et al. (12) in Anhui Province from 2015 to 2016 reported a MDR rate of 7.63%. Another study by Wang et al. (13) in Hainan Province from 2019 to 2021 found the MDR rate to be 19.19%. Similarly, research conducted by Wang et al. (14) in Luoyang City from 2019 to 2022 revealed a MDR rate of 11.3%. Furthermore, a study by Li et al. (15) in Hangzhou City from 2012 to 2022 reported a MDR rate of 5.3%. A study by Sambas et al. (16) in Mecca, Saudi Arabia, from 2009 to 2019 showed a MDR rate of 5.0%. A systematic review and meta-analysis of the prevalence of MDR-TB in Iran from 1981 to 2023 indicated a multidrug resistance rate of 12.31% (17). Additionally, Tengan et al. (18) systematic review and meta-analysis on the prevalence of MDR-TB in Latin America and the Caribbean reported a rate of 13.0%. A prospective cohort study by Aznar et al. (19) on the prevalence and risk factors of MDR-TB in Cubal, Angola, found a MDR rate of 25%. By comparing the results of these previous studies, we conclude that the MDR rate among TB patients in Wenzhou City is relatively low both within China and in the context of the global epidemic.

This study found that the proportion of MDR among notified patients with a history of TB treatment was higher than in new patients, which aligns with the findings of Du et al. (20) in Dalian, China, and Molla et al. (21) in East Africa. Numerous studies have identified previous treatment history as a risk factor for the development of acquired MDR (22–24). However, a study by Nsofor et al. (25) in Shanghai, China, revealed that over half of patients with a history of TB treatment developed drug resistance due to primary drug resistance rather than acquired drug resistance. Consequently, drug resistance screening should be conducted during the diagnosis and treatment of cases to facilitate the timely detection of primary multidrug resistance. Additionally, comprehensive management of the treatment of new patients should be reinforced to mitigate the risk of their progression to retreatment cases. This approach aims to reduce the spread of MDR-TB through early detection and proactive management.

From 2014 to 2023, the proportion of MDR-TB among notified cases in Wenzhou City demonstrated a significant downward trend. Concurrently, the proportions of RR-TB, HR-TB, and PDR-TB among notified cases exhibited slight decreases. These trends indicate an overall reduction in the proportion of drug-resistant TB in Wenzhou City. This positive outcome can be attributed to a series of prevention and control measures implemented over the years, including the comprehensive execution of the DOTS-Plus strategy, the expansion of pDST qualifications, and the provision of government subsidies to patients with DR-TB. Furthermore, collaborative projects, such as the prospective study on the treatment of RR-TB in partnership with the infection department team at Huashan Hospital, affiliated with Fudan University, have contributed to enhancing the success rate of MDR-TB treatment, curbing the spread of MDR-TB, and consequently reducing the drug resistance rate.

The proportion of migrant MDR-TB cases among all notified MDR-TB cases in Wenzhou City constitutes 47.96% of the total MDR-TB cases. This figure is relatively high compared to findings from other regions. For instance, a study conducted in Hangzhou indicated that migrant MDR-TB accounted for 46% of the total cases (15), while a report from Shanghai revealed that this proportion was 53% (26). Additionally, research by AI Mahrouqi et al. (27) in the Sultanate of Oman reported that migrant MDR-TB cases represented 35.6% of the total, and a study by Oliveira et al. (28) in Portugal found that the figure was 32.9%. The proportion of MDR-TB among notified migrant TB cases in this study was higher than that among notified local TB cases, aligning with results from previous studies (29, 30). The significant proportion and incidence of MDR-TB in the migrant population, corroborated by various studies indicating that migration is a risk factor for the development of MDR-TB (31, 32), underscore the necessity and importance of implementing effective prevention and control strategies specifically targeted at this demographic. Notably, the proportion of migrant MDR-TB in Wenzhou City has shown a year-on-year increase from 2014 to 2019, but declined significantly after 2020. This downward trend is consistent with our recent study in an older adult cohort [citing PMID: 40671759] (33), which employed time-series analysis to demonstrate that strict mobility-restriction policies during the COVID-19 pandemic (e.g., transportation limitations and community lockdowns) led to a transient decline in reported TB incidence during 2020–2021 (APC = −10.1, 95% CI: −15.3 to −4.7). Although the present study did not directly collect data on these control policies, the indirect evidence from the older adult-cohort study supports this inference. As we transition into the post-pandemic era, it remains imperative that prevention and control of MDR-TB among the migrant population continue to receive high priority.

The results of this study indicate that 64.21% of migrant MDR-TB patients originate from the migrant population in Zhejiang Province, while the remaining cases primarily come from areas outside Zhejiang, including Guizhou Province, Jiangxi Province, and Sichuan Province. The majority of migrant MDR-TB patients reside in Wenzhou. Our analysis identifies several contributing factors: First, Wenzhou’s economy is relatively developed, and its industrial structure is diversified (34), encompassing sectors such as manufacturing and commerce, which provide numerous employment opportunities and relatively higher income levels. This economic environment attracts labor from various levels, making it easier for the migrant population in Zhejiang Province to secure economic benefits by working and living in Wenzhou. Additionally, individuals from economically underdeveloped regions, such as Guizhou, Jiangxi, and Sichuan provinces, are drawn to Wenzhou’s economic vitality in hopes of improving their financial circumstances. Second, Zhejiang Province experiences frequent population movements, with Wenzhou, as a prominent economic hub, attracting many people from within the province. Furthermore, provinces like Guizhou, Jiangxi, and Sichuan have large population bases, contributing to significant migrant worker movements, and Wenzhou has emerged as a preferred destination for these individuals. Third, social networks formed by relatives and friends from the same village who are already residing and working in Wenzhou facilitate the migration process. Newcomers often follow these established connections, leading to a clustering effect that may result in an influx of patients into Wenzhou. These findings underscore the strong association between the migrant population and MDR-TB, highlighting the necessity for public health prevention and control strategies to account for regional economic disparities and the characteristics of the migrant population. Wenzhou has a developed economy and experiences a significant influx of population. It is advisable to enhance health screening at critical points, such as employment centers and entry points for migrant populations, to detect potential cases of MDR-TB early and prevent its spread. Additionally, it is important to increase awareness of MDR-TB in enterprises, communities, and other gathering places, thereby enhancing public understanding of prevention measures and promoting the adoption of healthy habits. Utilizing the network of local residents to train health promoters can facilitate the efficient dissemination of TB prevention and control information, establish a multi-level protection network, and ultimately reduce the risk and impact of MDR-TB transmission in Wenzhou and beyond.

Among the 339 migrant MDR-TB patients residing in Wenzhou, the primary areas of residence include Yueqing City, Yongjia County, and Ouhai District. Patients from Zhejiang Province predominantly migrate to Yueqing City, Yongjia County, and Ouhai District, while those from Guizhou Province primarily move to Rui’an City, Lucheng District, and Longwan District. Additionally, cases from Jiangxi Province mainly flow into Yueqing City and Lucheng District. Notably, migrant MDR-TB cases in Longwan District represent the highest proportion of all MDR-TB cases, accounting for 67.24%. Furthermore, Dongtou District, Ouhai District, Taishun County, Yueqing City, Yongjia County, and Lucheng District exhibit a higher prevalence of migrant MDR-TB cases, all exceeding 50%. These findings underscore the necessity of developing MDR-TB prevention and control strategies tailored for all districts and counties in Wenzhou City, providing a valuable reference for formulating effective interventions.

To translate our findings into immediate action, we propose three practical measures: Set up rapid on-site screening booths at Wenzhou South Railway Station, Shuangyu Coach Terminal, and major industrial parks; sputum smear and GeneXpert results are delivered the same day. Create a 24-h WeChat referral group linking Wenzhou with Guizhou, Jiangxi, and Sichuan to share patient information instantly and cut treatment interruption. Establish a “Migrant MDR-TB Rapid Response Team” led by Wenzhou Central Hospital together with county-level facilities to ensure referral and treatment initiation within 48 h of notification.

This study has several limitations. First, we did not assess whether these cases developed MDR-TB before or after arriving in Wenzhou, which may influence the interpretation of our results. Second, the economic structure of Wenzhou, and indeed China as a whole, is undergoing changes that could alter the composition of the migrant population in the future (35), thereby impacting the applicability of our research conclusions. Third, drug resistance was defined exclusively by phenotypic DST; the absence of genotypic data (Whole Genome Sequencing or line-probe assays) prevents us from distinguishing imported infections from local reactivation or transmission and limits insight into resistance mechanisms. Future work will integrate molecular surveillance and prospective genotypic–phenotypic linkage to refine MDR-TB control strategies.

Between 2014 and 2023, the proportion of MDR among notified TB cases in Wenzhou declined overall. Migrants contributed nearly half of all notified MDR-TB cases. Sustained, migrant-focused and district-specific interventions are required to further curb the spread of MDR-TB in Wenzhou.