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BackgroundMexico is one of the most important contributors of drug and multidrug-resistant tuberculosis in Latin America; however, knowledge of the genetic diversity of drug-resistant tuberculosis isolates is limited.MethodsIn this study, the genetic structure of 112 Mycobacterium tuberculosis strains from the southeastern Mexico was determined by spoligotyping and 24-loci MIRU-VNTRs.FindingsThe results show eight major lineages, the most of which was T1 (24%), followed by LAM (16%) and H (15%). A total of 29 (25%) isolates were identified as orphan. The most abundant SITs were SIT53/T1 and SIT42/LAM9 with 10 isolates each and SIT50/H3 with eight isolates. Fifty-two spoligotype patterns, twenty-seven clusters and ten clonal complexes were observed, demonstrating an important genetic diversity of drug and multidrug-resistant tuberculosis isolates in circulation and transmission level of these aggravated forms of tuberculosis. Being defined as orphan or as part of an orphan cluster, was a risk factor for multidrug resistant-tuberculosis (OR 2.5, IC 1.05–5.86 and OR 3.3, IC 1–11.03, respectively). Multiple correspondence analyses showed association of some clusters and SITs with specific geographical locations.ConclusionsOur study provides one of the most detailed description of the genetic structure of drug and multidrug-resistant tuberculosis strains in southeast Mexico, establishing for the first time a baseline of the genotypes observed in resistant isolates circulating, however further studies are required to better elucidate the genetic structure of tuberculosis in region and the factors that could be participating in their dispersion.

Background Mexico is on the top five countries with the highest number of TB cases in America continent, nevertheless, information about genotypes circulating is practically unknown. Considering the above this study aims to characterize the genetic diversity of TB in the city of Veracruz, México. Methods A cross-sectional study was conducted among positive smear samples from patients living in Veracruz City, samples were cultured, and first-line drug profiles determined. Genotyping was made by spoligotyping and MIRU-VNTR 24 loci. Associations of lineages, clusters, and variables were also analyzed. Results Among the 202 isolates analyzed resistance to at least one drug was observed in 60 (30%) isolates and 41(20%) were multidrug-resistant. Three major lineages were identified: L4/Euro-American (88%), L1/Indo-Oceanic (9%), and L2/East Asian (3%). The Euro-American lineage included more than six sublineages, the most abundant were: H (32%), T (23%), LAM (18%), and X (12%). 140 isolates (70%) were placed in 42 SITs patterns. Conclusions These results provide the first baseline data on the genetic structure of TB in the city of Veracruz. Sublineages H, X and LAM were predominant; however, it was founded an important diversity of genotypes that could contribute to the dispersion of TB and explain the high prevalence. This information might be useful for the development of further interventions to reduce impact of TB.

An important diversity of lineages and unknown genotypes was identified; however, more studies are necessary in order to understand the characteristics of the genotypes displayed in the region. There is no doubt regarding the need for a molecular epidemiological surveillance system that can help to evaluate the dynamics of genotypes circulating in the country and support strategies for the prevention and management of populations affected by TB.