RESEARCH ARTICLE Tuberculous Lymphadenitis in Ethiopia Predominantly Caused by Strains Belonging to the Delhi/CAS Lineage and Newly Identified Ethiopian Clades of the Mycobacterium tuberculosis Complex

Background Recently, newly defined clades ofMycobacterium tuberculosis complex (MTBC) strains, namely Ethiopia 1–3 and Ethiopia H37Rv-like strains, and other clades associated with pul-monary TB (PTB) were identified in Ethiopia. In this study, we investigated whether these new strain types exhibit an increased ability to cause TB lymphadenitis (TBLN) and raised the question, if particular MTBC strains derived from TBLN patients in northern Ethiopia are genetically adapted to their local hosts and/or to the TBLN. Methods Genotyping of 196 MTBC strains isolated from TBLN patients was performed by spoligotyp-ing and 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats (MIRU-VNTR) typing. A statistical analysis was carried out to see possible associa-tions between patient characteristics and phylogenetic MTBC strain classification