OBJECTIVES: The globally distributed "Beijing" lineage of Mycobacterium tuberculosis has been associated with outbreaks worldwide. Laboratory based studies have suggested that Beijing lineage may have increased fitness; however, it has not been established whether these differences are of epidemiological significance with regards to transmission. Therefore, we undertook a systematic review of epidemiological studies of tuberculosis clustering to compare the transmission dynamics of Beijing lineages versus the non-Beijing lineages. METHODS: We systematically searched Embase and MEDLINE before 31st December 2018, for studies which provided information on the transmission dynamics of the different M. tuberculosis lineages. We included articles that conducted population-based cross-sectional or longitudinal molecular epidemiological studies reporting information about extent of transmission of different lineages. The protocol for this systematic review was prospectively registered with PROSPERO (CDR42018088579). RESULTS: Of 2855 records identified by the search, 46 were included in the review, containing 42,700 patients from 27 countries. Beijing lineage was the most prevalent and highly clustered strain in 72.4% of the studies and had a higher likelihood of transmission than non-Beijing lineages (OR 181 [95% 128-257], I2 = 940%, tau2 = 059, p < 001). CONCLUSIONS: Despite considerable heterogeneity across epidemiological contexts, Beijing lineage appears to be more transmissible than other lineages.
Karmakar, M., Trauer, J. M., Ascher, D. B., & Denholm, J. T. (2019). Hyper transmission of Beijing lineage Mycobacterium tuberculosis: Systematic review and Meta-analysis. Journal of Infection, 79(6), 572-581. https://doi.org/10.1016/j.jinf.2019.09.016