Listeria monocytogenes: silage, sandwiches and science

Abstract

Listeria monocytogenes is amongst the most intriguing and well studied of the pathogenic bacteria. However, the understanding and perspective one has of L. monocytogenes depends to a large extent on the microbiological issues with which one is faced as a part of your professional duties. The focus of the veterinary clinician or investigator is likely to be foremost on the neurologic (circling disease) and reproductive diseases L. monocytogenes causes. To the food microbiologist, the principal concern is to prevent introduction of L. monocytogenes into food products, or to identify its presence and prevent its multiplication to numbers of organisms that are likely to pose a substantial risk to humans who ingest the product. To the cellular immunologist, listeriosis represents a robust murine model that helped to elucidate many important concepts in innate and adaptive immunity, and L. monocytogenes is a potential vector for delivery of novel vaccines. To the student of molecular pathogenesis, L. monocytogenes is a powerful and well-characterized model organism for studying the cellular microbiology of an intracellular pathogen. In this brief overview, I will attempt to highlight some of the classical observations, and contemporary insights, on L. monocytogenes and listeriosis, and integrate these perspectives into a common framework. By so doing, I hope to provide those with one perspective on listeriosis with an appreciation of the broad array of problems and issues faced by those who focus on some other aspect of L. monocytogenes and its pathogenesis.

An overview of Listeria monocytogenes contamination in ready to eat meat, dairy and fishery foods

“…Animal contamination can occur by consumption of water, pasture or silage and the presence of L. monocytogenes in fecal excretion was not necessarily related to the occurrence of listeriosis (CZUPRYNSKI, 2005;ESTEBAN et al, 2009).…”

“…In addition, failures in compliance with good manufacturing and hygiene practices allow the bacterium to be carried into the industry by shoes, clothing, transport equipment and people. In industrial facilities L. monocytogenes can be reported in drains, mats, coolers, air filters, walls, cleaning utensils and other environments that are wet, cold and difficult to clean, where it can survive for long periods due to its ability to form biofilms and resist to bacterial agents that causes bacterium stresses (CZUPRYNSKI, 2005;GANDHI & CHIKINDAS, 2007;CESAR et al, 2011;LEONG et al, 2014).…”

Contribution of Chitinases to Listeria monocytogenes Pathogenesis

“…Listeria monocytogenes is a Gram-positive bacterium that is found as an inhabitant of soil, water, and decaying vegetation, where the organism is believed to live as a saprophyte (12,13,16). Upon consumption of the bacterium by a susceptible host, L. monocytogenes adopts a pathogenic lifestyle that can lead to serious and sometimes fatal infections (1,3,15,22,32).…”

Genome Sequence of Listeria monocytogenes 07PF0776, a Cardiotropic Serovar 4b Strain

“…isteria monocytogenes is a Gram-positive bacterium that lives as a saprophyte in soil but which is capable of causing invasive disease in both humans and livestock (6,8). Acute listerial gastroenteritis in humans can occur across broad populations, but more invasive forms of the disease are typically restricted to the immunocompromised, such as HIV/AIDS patients, the elderly, and pregnant women (7).…”