Characterisation of pks15/1 in clinical isolates of Mycobacterium tuberculosis from Mexico

Abstract

Tuberculosis (TB) is an infectocontagious respiratory disease caused by members of the Mycobacterium tuberculosis complex. A 7 base pair (bp) deletion in the locus polyketide synthase (pks)15/1 is described as polymorphic among members of the M. tuberculosis complex, enabling the identification of Euro-American, Indo-Oceanic and Asian lineages. The aim of this study was to characterise this locus in TB isolates from Mexico. One hundred twenty clinical isolates were recovered from the states of Veracruz and Estado de Mexico. We determined the nucleotide sequence of a ± 400 bp fragment of the locus pks15/1, while genotypic characterisation was performed by spoligotyping. One hundred and fifty isolates contained the 7 bp deletion, while five had the wild type locus. Lineages X (22%), LAM (18%) and T (17%) were the most frequent; only three (2%) of the isolates were identified as Beijing and two (1%) EAI-Manila. The wild type pks15/1 locus was observed in all Asian lineage isolates tested. Our results confirm the utility of locus pks15/1 as a molecular marker for identifying Asian lineages of the M. tuberculosis complex. This marker could be of great value in the epidemiological surveillance of TB, especially in countries like Mexico, where the prevalence of such lineages is unknown.

Genetic Diversity and Drug Resistance of Mycobacterium tuberculosis Complex Isolates and Nontuberculous Mycobacteria Identification from Presumptive Tuberculosis Cases in Oaxaca, Mexico

“…The genotypic diversity of clinical isolates in the state of Oaxaca differs from other national reports (Macias Parra et al, 2011;Martinez-Guarneros et al, 2013;Zenteno-Cuevas et al, 2013), specifically those from the northern and central region of the country (Lopez-Alvarez et al, 2010;Molina-Torres et al, 2010), where the genotypes T, LAM and X are the most frequently reported. The T lineage was not detected in the oaxacan population, besides LAM and X which occurred in low frequency, 12% and 10% respectively.…”

Description of the population structure and genetic diversity of tuberculosis in Estado de México, a low prevalence setting from Mexico

“…It is notable that only seven isolates showed an East‐Asian, Indo‐Oceanic or East‐African‐Indian lineage, particularly when we consider the close proximity of Estado de México with the two most important contributors of these lineages in Mexico: Guerrero and San Luis Potosí . These lineages, especially Beijing, are traditionally considered to be highly virulent, with a strong tendency toward drug resistance and dominance in Asian populations; however, distribution in Latin America seems to be discrete and rarely associated with significant outbreaks .The low occurrence of these lineages in the region could have two possible explanations: The first is related to the recent incorporation of these lineages in Estado de México and the second is the containment of their dispersion by the dominant circulating lineages that can rapidly infect the susceptible population. We require more detailed surveillance of these lineages, over a longer time period, in order to obtain a clearer understanding of the dynamics present in this setting.…”