Genetic diversity and drug resistance of <i>Mycobacterium tuberculosis</i> in Ecuador

Background The genetic diversity of Mycobacterium tuberculosis in Quito, Ecuador is not well known. Objective To investigate mutations related to drug resistance and bacterial genotypes in M. tuberculosis strains in Ecuador. Design This was a retrospective study of M. tuberculosis isolates from 104 patients. Isolates were phenotypically resistant to rifampicin (RMP) and/or isoniazid (INH). The genotype was determined using 24-locus mycobacterial interspersed repetitive units-variable-number tandem repeats (MIRU-VNTR). Results Isolates showed mutations in the rpo B and kat G genes, and the inh A promoter. In rpo B, we found 13 genetic alterations at codons 511, 513, 514, 515, 516, 526 and 531. Forty-six (44.2%) RMP-resistant isolates belonged to codon 531. In kat G, there were nine genetic alterations at codons 296, 312, 314, 315, 322, 324 and 351. Fifty-three (51%) INH-resistant isolates belonged to codon 315. Five mutations not previously described were identified in kat G: Thr324Ser, Thr314Ala, Ala312Pro, Trp351Stop and deleted G at 296 codon. The Latin American Mediterranean (LAM) (33.7%) and Ghana (30.8%) lineages presented most of the main mutations observed. Conclusion This is the first report from Ecuador; it describes five new mutations in kat G and indicates that LAM is the most prevalent lineage.