Tuberculosis transmission and resistance among Ukrainian migrants and its impact on multidrug-resistant tuberculosis dynamics in high-influx host countries

The war in Ukraine triggered unprecedented migration into Central Europe, raising concerns regarding tuberculosis (TB) spread. We conducted a molecular-epidemiological study including all Ukrainian migrants with culture-confirmed TB in Slovakia and the Czech Republic between September 2021 and December 2024 (n = 229), together with all other multidrug-resistant (MDR) TB cases reported in these countries between 2023 and 2024 (n = 28). Whole-genome sequencing (WGS) was performed on cultured Mycobacterium tuberculosis complex (MTBC) isolates, and the resulting data were used for phylogenetic reconstruction, lineage classification, genomic resistance prediction, and cluster analysis. Since the war began in 2022, the share of TB cases from Ukrainian migrants in the Czech Republic rose significantly (P < 0.001), along with an evident increase in total MDR-TB cases. Out of 199 MTBC strains from Ukrainian migrants with good-quality WGS data, 129 (64.8%) were predicted to be susceptible, 25 MDR (12.6%), 8 pre-extensively drug-resistant (pre-XDR; 4%), and 37 (18.6%) had other resistance patterns including bedaquiline/clofazimine monoresistance. Among MDR/pre-XDR strains (n = 59) lineage 2 predominated (63.5%), mainly belonging to the Central Asia clades (45.0%) and the Europe/Russian W148 outbreak clone (52.9%), followed by lineage 4 (28.9%). Cluster analysis (5 allele threshold) identified 10 MDR/pre-XDR TB clusters, each with two isolates. Only one of those clusters included a Ukrainian migrant and non-Ukrainian patient from the host country. Migration increased both, the TB and MDR-TB burden especially in the Czech Republic. Transmission of imported MTBC strains from migrants to host populations appears to be limited, but needs to be closely monitered prospectively.