Genomic Approach of Listeria monocytogenes Strains Isolated from Deli-Meats in Mexico

Area of Science:

• Food Microbiology
• Genomics
• Public Health

Background:

• Listeria monocytogenes is a significant foodborne pathogen causing listeriosis globally.
• In Mexico, L. monocytogenes is a recognized hazard in deli-meats, yet genomic data on transmission and virulence factors is limited.
• Understanding the genetic makeup of these strains is crucial for risk assessment.

Purpose of the Study:

• To perform high-quality genome sequencing and comparative genomic analysis of L. monocytogenes strains from Mexican deli-meats.
• To identify serotypes, lineages, clonal complexes, and sequence types.
• To explore virulence factors, antimicrobial resistance, and stress survival traits.

Main Methods:

• Whole-genome sequencing of four L. monocytogenes strains.
• In silico analysis for serotyping, lineage, clonal complex (CC), and multilocus sequence typing (ST).
• Comparative genomics to assess pangenome, core genome, mobile elements, and identify virulence and resistance genes.

Main Results:

• Genome drafts revealed strains belonging to lineage I, specifically serotype 4b (CC2, ST1) and 1/2b (CC5, ST5).
• All analyzed strains harbored the Listeria monocytogenes pathogenicity island-1 (LIPI-1) and showed identical in silico multidrug resistance patterns (fosX, norB, mprF, lin).
• Genomic differences were primarily attributed to phage insertions, indicating largely syntenic genomes.

Conclusions:

• These findings enhance the understanding of L. monocytogenes biology in Mexican deli-meats.
• The identified strains belong to epidemic lineages and possess virulence genes associated with human disease, highlighting a potential public health concern.
• Genomic surveillance is essential for monitoring foodborne pathogens and mitigating risks associated with contaminated food products.