Genotypes of Mycobacterium tuberculosis isolated in Manaus, Amazonas, Brasil.

Brazil, like the most low-middle income countries, presents a concern situation regarding Tuberculosis (TB), a global health problem caused by pathogen Mycobacterium tuberculosis. Only in 2020, 66,819 new cases were diagnosed in national territory, with an annual incidence rate of 31.6/100,000 inhabitants. The Manaus city leads among the Brazilian capitals, reaching incidence rate of 90.1/100,000 inhabitants. Among the tools for TB control, there is molecular epidemiology that involves techniques for explanation about phylogeny, population genetics, geographic tracking of strains, frequency of reactivation and reinfection and properties related to virulence. Thus, the aim of this study was to genotype the strains of M. tuberculosis isolated from patients with pulmonary Tuberculosis, in Manaus, Amazonas. For this, it was used the MIRU-VNTR (‘Mycobacterial Interspersed Repetitive Units-Variable Numbers of Tandem Repeats’) technique. This technique is reproducible, simple and analyzes 12 loci (MIRU02, MIRU04, MIRU10, MIRU16, MIRU20, MIRU23, MIRU24, MIRU26, MIRU27, MIRU31, MIRU39 and MIRU40) present in M. tuberculosis chromosome, enabling the comparison and geographic lineages of individual strains. For this, 28 strains were selected from the Collection of Microorganisms of Medical Interest, at Laboratory of Mycobacteriology, Instituto Nacional de Pesquisas da Amazônia - INPA, and carried out the genotyping of 12 MIRU-VNTR loci. It was possible to identify 6 lineages, in which Haarlem and LAM were the most frequent, 32.14% and 28.57%, respectively. The other genotypes were EAI (14.28%), Cameroon (3.57%), Beijing (3.57%) and X (3.57%). The 45/18 “A” and 45/18 “B” isolates, collected from the same patient on different dates, presented the same genetic profile. This permit to conclude that there was persistence of same population of M. tuberculosis during the TB treatment or TB recurrence. In 140/18 isolate, double alleles were found for MIRU24, alleles 6 and 7 (465 bp and 518 bp), suggesting the probable presence of a clonal sub-population of M. tuberculosis. Among the MIRU-VNTR loci, those with the greatest allelic diversity were MIRU40 (0.76), MIRU10 (0.68) and MIRU23 (0.68). We did not expect, but the Haarlem lineage was more frequent among the genotypes found. Despite the small number of M. tuberculosis strains, this study was essential to know the genotypic diversity of M. tuberculosis. This could be partly responsible for the high incidence of Tuberculosis in Manaus, Amazonas.