Abstract
BackgroundThe Latin American & Mediterranean (LAM) spoligotype family is one of the most successful genotype of Mycobacterium tuberculosis worldwide and particularly prevalent in South-America. Within this family, a sublineage named Region of Difference Rio (RDRio) was reported initially in Brazil and is characterized by a genomic deletion of about 26.3 kb. This lineage seems to show a specific adaptation to the Euro-Latin American population. In this context, we sought to evaluate the LAM family and the presence of the RDRio genotype in samples from three Latin American countries including Paraguay, Venezuela and Argentina. To detect LAM strains reliably we applied a typing scheme using spoligotyping, 12 loci MIRU-VNTR, the Ag85C103 SNP and the regions of difference RDRio and RD174. IS6110-RFLP results were also used when available.ResultsGenotyping of 413 M. tuberculosis isolates from three Latin-American countries detected LAM (46%) and the ill-defined T clade (16%) as the most frequent families. The highest clustering rate was detected in the sample population from the city of Caracas in Venezuela. We observed considerable differences in the presence of the RDRio lineage, with high frequency in Caracas-Venezuela (55%) and low frequency in Buenos Aires-Argentina (11%) and Paraguay (10%). The molecular markers (RD174, Ag85C103, MIRU02-MIRU40 signature) of the RDRio lineage were essentially confirmed. For the LAM family, the most polymorphic loci were MIRU40, MIRU31, MIRU10, MIRU26, MIRU16 and the least polymorphic MIRU24, MIRU20, MIRU04, MIRU23.ConclusionsOur results suggest a differential adaptation of LAM-sublineages in neighboring populations and that RDRio strains spread regionally with different rates of distribution. The Ag85C SNP and RDs (RD174, RDRio) tested in this study can in fact facilitate molecular epidemiological studies of LAM strains in endemic settings and low-income countries.
Highlights
The Latin American & Mediterranean (LAM) spoligotype family is one of the most successful genotype of Mycobacterium tuberculosis worldwide and prevalent in South-America
LAM1 and LAM2 were reported to be exclusively of the Region of Difference Rio (RDRio) genotype, whereas LAM3 was solely represented in the Wild type (WT) genotype, and LAM4, LAM5, LAM6, LAM9 were represented in both the RDRio and WT LAM genotypes [25]
Because of the high frequency and diversity of LAM strains in South America, we performed a cross-sectional study to evaluate the behavior of the LAM and the RDRio genotypes, in samples from Paraguay as well as in samples from nearby Buenos Aires Province (Argentina) and the distant City of Caracas (Venezuela) for comparison
Summary
The Latin American & Mediterranean (LAM) spoligotype family is one of the most successful genotype of Mycobacterium tuberculosis worldwide and prevalent in South-America Within this family, a sublineage named Region of Difference Rio (RDRio) was reported initially in Brazil and is characterized by a genomic deletion of about 26.3 kb. A sublineage named Region of Difference Rio (RDRio) was reported initially in Brazil and is characterized by a genomic deletion of about 26.3 kb This lineage seems to show a specific adaptation to the Euro-Latin American population. Genetic variation has been shown to impact on pathogenicity, virulence, transmissibility or the ability to subvert host immune responses [5,6,7,8,9,10] Available databases such as SITVITWEB [11] and MIRU-VNTRplus [2] allow comparison of TB multimarker-based genotyping data and global epidemiological studies [11, 12]. We sought to assess the usefulness of different genetic markers to detect the LAM family at a regional and country-based level
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