Pathogenicity and virulence of Listeria monocytogenes: A trip from environmental to medical microbiology

Abstract

Listeria monocytogenes is a saprophytic gram-positive bacterium, and an opportunistic foodborne pathogen that can produce listeriosis in humans and animals. It has evolved an exceptional ability to adapt to stress conditions encountered in different environments, resulting in a ubiquitous distribution. Because some food preservation methods and disinfection protocols in food-processing environments cannot efficiently prevent contaminations, L. monocytogenes constitutes a threat to human health and a challenge to food safety. In the host, Listeria colonizes the gastrointestinal tract, crosses the intestinal barrier, and disseminates through the blood to target organs. In immunocompromised individuals, the elderly, and pregnant women, the pathogen can cross the blood-brain and placental barriers, leading to neurolisteriosis and materno-fetal listeriosis. Molecular and cell biology studies of infection have proven L. monocytogenes to be a versatile pathogen that deploys unique strategies to invade different cell types, survive and move inside the eukaryotic host cell, and spread from cell to cell. Here, we present the multifaceted Listeria life cycle from a comprehensive perspective. We discuss genetic features of pathogenic Listeria species, analyze factors involved in food contamination, and review bacterial strategies to tolerate stresses encountered both during food processing and along the host’s gastrointestinal tract. Then we dissect host–pathogen interactions underlying listerial pathogenesis in mammals from a cell biology and systemic point of view. Finally, we summarize the epidemiology, pathophysiology, and clinical features of listeriosis in humans and animals. This work aims to gather information from different fields crucial for a comprehensive understanding of the pathogenesis of L. monocytogenes.

Landscape of Stress Response and Virulence Genes Among Listeria monocytogenes Strains

“…Furthermore, comparative genomics analysis between hypo-and hypervirulent clones have uncovered the specific virulence clusters such as LIPI-3 (present approximately in 50% of lineage I strains) and LIPI-4. Regardless of these facts, the regulatory authorities consider all strains of L. monocytogenes to be equally pathogenic (Vázquez-Boland et al, 2020;Quereda et al, 2021), whereas the food safety risk attributed to different subgroups differ (Chen et al, 2006). : 0-white; 1-gray; 2-green; 4-dark green; 10-17-blue; 18-black.…”

“…Moreover, it is crucial to identify the interactions between stress response and virulence and to know how this microorganism survives, adapts to adverse conditions, and triggers genes involved in virulence or promoting persistence. This would help to explain the observed inverse correlation between strains with a higher prevalence of genes involved in BC tolerance, as well as other stress-related genes, amongst hypovirulent (i.e., low virulence) lineage II strains ( Quereda et al, 2021 ). All this knowledge may contribute to the development of new intervention strategies for better control of the level of L. monocytogenes in the food chain.…”

Role of IL-10-Producing Natural Killer Cells in the Regulatory Mechanisms of Inflammation during Systemic Infection

“…Although the incidence of severe listeriosis is low, Lm infections are a public health issue, owing to the frequency of outbreaks associated with contaminated food. The factors involved in the increased susceptibility of some individuals to severe infections are poorly understood, but systemic infections are mostly reported in the elderly, pregnant women, and immunocompromised individuals [ 14 , 15 , 16 ]. Most of the knowledge regarding pathogenesis and immune response to Lm has been obtained from the murine model of listeriosis.…”

Heterologous expression of pediocin/papA in Bacillus subtilis

“…Nisin is a class Iα bacteriocin that undergoes posttranslational modification [ 5 ]. Pediocin (PA-1) is a class IIα bacteriocin, heat-stable, ribosomally synthesized, unmodified peptide [ 6 ], with anti- Listeria effects [ 7 ]. Nisin is a broad-spectrum bacteriocin and has shown efficacy in the control of clinically relevant methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate S. aureus (VISA), and vancomycin-resistant Enterococcus (VRE) [ 3 , 8 ].…”