The genotype of the largest pre-XDR TB cluster was characterized by an inhA promoter mutation at position 17 and the katG AGC315ACC, rpoB GAC516GTC, embB ATG306ATA, rrs A513C, and rrs A1401G nucleotide substitutions as well as an insertion in the pncA gene at position 172G. Here, INHA is linked to tuberculosis.