Transmission of drug-resistant Mycobacterium tuberculosis isolates between Finnish- and foreign-born cases, 2014–2021: A molecular epidemiological study

• Published in: Tuberculosis (Edinburgh, Scotland) Scotland), 2024-05, Vol.146, p.102492-102492, Article 102492
• Main Authors: Zhu, Jiahui, Haanpera, Marjo, Mentula, Silja, Vapalahti, Olli, Soini, Hanna, Sironen, Tarja, Kant, Ravi, Zakham, Fathiah
• Format: Article
• Language: English
• Subjects: Drug resistance; Genetic cluster; Mutation; Mycobacterium tuberculosis; Whole genome sequencing
• ISSN: 1472-9792; 1873-281X
• DOI: 10.1016/j.tube.2024.102492

Data on the molecular epidemiology and transmission of drug-resistant Mycobacterium tuberculosis (MTB) in low-incidence settings with immigration from high-incidence settings is limited. We included 115 drug-resistant (DR) MTB isolates with whole-genome sequencing data isolated in Finland between 2014 and 2021. Potential transmission clusters were identified using a threshold of 12 single-nucleotide polymorphisms (SNPs). Highly related clusters were identified using a threshold of 5 SNPs. Of the 115 DR MTB isolates, 31 (27.0%) isolates were from Finnish-born cases and 84 (73.0%) were from foreign-born cases. The proportion of multidrug-resistant (MDR) MTB isolates (30/84, 35.7%) from foreign-born cases was higher than that of MDR MTB isolates from Finnish-born cases (8/31, 25.8%). Lineage 2 (40/115, 34.8%) and lineage 4 (40/115, 34.8%) were the most prevalent lineages. A total of 25 (21.7%) isolates were classified into eight potential transmission clusters (≤12 SNPs). Furthermore, five highly related clusters (≤5 SNPs) were identified, including three DR MTB isolates from Finnish-born cases and 14 DR isolates from foreign-born cases. The risk of DR MTB transmission between Finnish- and foreign-born persons is not negligible. Further research on clustering analysis in drug-susceptible MTB is worth to inform tuberculosis management and control in low-incidence settings with increasing immigration. •MDR-TB is more prevalent among foreign-born DR-TB than Finnish-born DR-TB.•Lineage 4 and lineage 2 were prevalent lineages in DR-TB cases in Finland.•Transmission of DR MTB between Finnish- and foreign-born cases is uncommon.