Listeria monocytogenes
Peter M. Lydyard, Michael F. Cole, John Holton, William L. Irving, Nino Porakishvili, Pradhib Venkatesan, Katherine N. Ward in Case Studies in Infectious Disease, 2010
Listeria monocytogenes is the cause of human disease. It is a gram-positive nonsporing motile bacillus (Figure 2). There are six species of Listeria: L. monocytogenes, L. ivanovii, L. welshimeri, L. innocua, L. seeligeri, and L. grayi. The most common cause of human disease is L. monocytogenes, although L. ivanovii can rarely cause disease. Listeria species grow on blood agar (see Figure 1) and L. monocytogenes produces a narrow zone of β-hemolysis often only seen beneath the colonies. The organism grows at 37°C but can also grow slowly at 4°C and this can be used as an enrichment technique when examining foodstuff. The organism shows a characteristic tumbling (end over end) movement at 25°C, which is diagnostic. L. monocytogenes has several serotypes based on cell wall (O) and flagellar (H) antigens. The majority of disease is caused by serotypes 1/2a, 1/2b, and 4b. Several molecular subtyping techniques (multilocus enzyme electrophoresis, pulse field gel electrophoresis, and ribotyping) have been found useful in epidemiological investigations.
How Bacteria Cause Disease
Keith Struthers in Clinical Microbiology, 2017
Bacteria including the β-haemolytic streptococci produce extracellular proteins termed haemolysins. These proteins are able to disrupt host cell membranes by enzymatic or detergent action, resulting in cell death by lysis (Figure 2.23). This haemolytic activity is demonstrated in the laboratory by the lysis (clearing) around colonies of bacteria when they are grown on blood agar. Important to the organism is the ability of the haemolysin to disrupt the cytoplasmic membrane of phagocytes, thus compromising the action of these cells. Listeria monocytogenes is a small gram-positive bacillus that can cause invasive disease. This organism produces a haemolysin, which degrades the membrane of the phagosome. When phagocytosed, Listeria monocytogenes is able to escape into the cytoplasm where it cannot be destroyed (Figure 2.24).
Listeria monocytogenes
Dongyou Liu in Laboratory Models for Foodborne Infections, 2017
Listeria monocytogenes typically causes infection in humans when ready-to-eat food products are contaminated during processing1; the bacteria increase in number during refrigerated storage,2 and then the food is consumed without adequate heating.3 Ingestion of L. monocytogenes leads to a wide spectrum of clinical outcomes, ranging from self-limiting gastroenteritis to life-threatening systemic infections of the blood, brain, and placenta that have a high mortality rate (25%–30%) even in patients receiving antibiotic treatment.4 The true incidence of intestinal infection is not known, as most people do not seek medical treatment for mild gastroenteritis, and L. monocytogenes is not commonly isolated from stool without the use of a specific enrichment broth.5 However, it is thought that the infection rate for heavily contaminated foods is likely to be high.6,7 After a short incubation period that can range from a few days up to several weeks, L. monocytogenes disseminates and then crosses the blood–brain barrier or the placenta in pregnant women. A retrospective analysis of recent outbreaks found that gastrointestinal symptoms were noted within 24 h of ingestion and bacteremia occurred within 2 days.8 However, it took an average of 9 days for central nervous system manifestations to develop, and much longer (17–67 days) for pregnancy-associated cases to be reported.
Effect of paeonol against bacterial growth, biofilm formation and dispersal of Staphylococcus aureus and Listeria monocytogenes in vitro
Published in Biofouling, 2022
Qiao Zeng, Yuting Fu, Min Yang, Ting Wang, Ying Wang, Shenghua Lv, Weidong Qian
Listeria monocytogenes is a Gram-positive, facultative intracellular bacterial pathogen that is involved in severe infections in humans, and can give rise to a spectrum of clinical illnesses in vulnerable populations at higher risk for invasive disease, including newborn children, the elderly, or immunocompromised individuals (Czuprynski 2005). L. monocytogenes is also a common organism which is found widely in natural environments, and survives there for up to several months (Ricci et al. 2018). This bacterium is transmitted predominantly through contaminated food and can be isolated from a wide range of foods, including dairy products, meat products, vegetables, fruits, and seafoods (Jami et al. 2014; Novoslavskij et al. 2016; Ricci et al. 2018). Previous investigations have shown that the top 30 known foodborne pathogens caused ∼ 9.4 million cases each year in the USA, in which L. monocytogenes ranked second (approximately 26%) as the cause of foodborne illnesses (Scallan et al. 2011).
Alfa-1-antitrypsin deficiency: a predisposing factor leading to invasive infections?
Published in Infectious Diseases, 2020
Sanne De Smet, Jan Dierick, Sophia Steyaert, Marie Schurgers, Christophe Van Steenkiste, Sarah Loof
Listeria monocytogenes is the only Listeria species that regularly infects humans. It is a facultative intracellular parasite and its primary habitat is the soil and decaying vegetable matter. Potentiated by its ability to multiply at 4 degrees Celsius, it contaminates fresh and processed poultry and meat, vegetables, raw milk, cheese, smoked salmon… Most Listeria infections in adults are thought to result from oral ingestion and subsequent intestinal mucosal penetration and systemic infection. Immunity to Listeria relies mostly on T cell activation of macrophages, which clear Listeria from the blood. Consecutively, factors that impair macrophage survival or function are associated with increased susceptibility to listerial infection [5,6]. Listeria monocytogenes has a broad clinical spectrum ranging from febrile gastro-enteritis over disseminated disease to meningo-encephalitis [7].
Absence of TNF Leads to Alternative Activation in Peritoneal Macrophages in Experimental Listeria Monocytogenes Infection
Published in Immunological Investigations, 2022
Xinying Li, Chen Chen, Lianjun Zhang, Xiaomin Cheng, Huiwu Geng, Qiang Ji, Chao Li, Huili Chen, Heinrich Körner, Xiaoying Liu
Listeria monocytogenes are Gram-positive bacteria that can cause severe infections in pregnant women, newborn and immunocompromised individuals (Radoshevich and Cossart 2018). The bacteria are rapidly phagocytosed by macrophages but have the ability to escape the phagolysosome by secreting a membranolytic protein. This toxin, listeriolysin O (LLO), is essential for bacterial virulence (Vazquez-Boland et al. 2001). After escape from the phagolysosome, L. monocytogenes replicate in the cytosol of infected macrophages. The pathogens can be eliminated once an antigen-specific CD8+ T cell response has been initiated (Harty and Bevan 1996). However, before an adaptive immunity response can be established, monocytes differentiate in the spleen into tumour necrosis factor-α (TNF) and inducible nitric oxide synthase (iNOS) producing dendritic cells (TipDCs) to control infection (Serbina et al. 2003).
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