Probing the Evolution of Genes Associated With DNA Methylation inListeria monocytogenes

Abstract

In the last decade, there have been increased reports of atypicalListeriaand the discovery of new species. There are public health concerns that new strains may come with increased pathogenicity. Hence, this study aimed to establish the prevalence, evolutionary lineage and ancestry of aListeria monocytogenescollection that includes isolates that harbour a unique set of methylase genes. The addition of methyl groups to DNA can interfere with transcription. Allelic-specific lineage analysis and ribotyping with southern hybridization were carried out after which further phylogenetic analysis was performedin silico. Results show that all the methylase strains belonged to Lineage I and were serotypes 4b or 4d. All designated ancestral strains also belonged to Lineage 1. AListeria monocytogenesplasmid from a serotype 1/2a (Lineage II) contained sequences homologous to that of Lineage I isolates. The methylase nucleotide sequence in the strains studied appears to be highly conserved inListeria monocytogenesand not yet orthologous among other bacterial genera. It is of epidemiological interest and public benefit if wider or continuous surveillance is carried out to ascertain if these rare strains are linked with increased pathogenesis, food type or geographical region.

Listeria monocytogenes from Food Products and Food Associated Environments: Antimicrobial Resistance, Genetic Clustering and Biofilm Insights

“…This pathogen is responsible for the spread of listeriosis, primarily through the ingestion of contaminated food. The disease can cause serious complications such as meningitis and septicemia [10] and is associated with a high morbidity and mortality [14], especially among populations at risk such as the elderly, pregnant women, newborns, and immunocompromised people [4,7]. Although the incidence of listeriosis is relatively low, mortality rate is high, affecting approximately 20-25% of patients [15,16].…”

“…In recent years, whole-genome sequencing (WGS) has become increasingly important in determining the characteristics and relationships of diverse L. monocytogenes strains isolated in many food productions [1,14] and in linking them to human disease. Bacterial WGS technology is used to accurately identify pathogens and genotypes through techniques such as multiloccus sequence typing (MLST), clonal complex (CC) identification, core genome MLST (cgMLST9, CRISPR-Cas), and serogrouping.…”