Nationwide phylogenomic surveillance of Mycobacterium tuberculosis in Mexico reveals pathogenic and drug resistant signatures of the prevailing L4 sublineage

Background

Tuberculosis disease is a major global health concern. In Mexico, information regarding the genomic variants of Mycobacterium tuberculosis (MTB) prevailing in the country and the existence of specific biogeographical patterns remains extremely scarce.

Objective

This study aimed to identify the genotypic patterns of MTB isolates in Mexico and determine the genes and specific single nucleotide polymorphisms involved in the evolution of these populations.

Methods

Phylogenomic and pan-genomic analyses were performed using publicly available Mexican MTB genomes along with 33 newly sequenced genomes from Jalisco, considering a global context.

Results

The L4 sublineages of MTB, such as L4.1.1 (X), L4.1.2 (H), and L4.3 (LAM), were the most prevalent in Mexico. We found exclusive mutations and gene clusters in a virulent sublineage L4.1.1.3 (X3), which is endemic to Mexico. These genes encoded three PE/PPE family proteins: a multidrug transporter, thioredoxin domain-containing protein, quinone-dependent l-lactate dehydrogenase, DUF1725 domain-containing protein, amidase, poly (A) polymerase, and six hypothetical/uncharacterised proteins. Additionally, the genes encode an ESX-1 secretion-associated protein and a deazaflavin-dependent nitroreductase (ddn).

Conclusion

X3 was distinguished from the rest of the sublineages by containing genes related to pathogenicity and virulence, as well as a gene linked to delamanid, an antibiotic for active multidrug-resistant tuberculosis. These findings provide valuable insight into the circulation and spread of MTB in Mexico.