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Pathogenicity and Virulence
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
Phagocytized L. monocytogenes releases a cytolytic exotoxin, listeriolysin O, that disrupts the phagosomal membrane following its activation at pH 5.5. Other microbial enzymes, including two types of phospholipase C and a lecithinase, are believed to have subsidiary roles in membrane lysis. Within the cytoplasm Listeria replicate rapidly for two to three hours and then become surrounded by actin filaments that are organized at one end to form a polar tail. Continued deposition of actin at the polar tail pushes the bacterium through the cytoplasm at a remarkably rapid rate. At the cell periphery pseudopod formation is induced, and the pseudopod, with Listeria inside, is ingested by a neighboring cell. The double layer of cell membranes is then disrupted by bacterial cytolysins, releasing Listeria into the cytoplasm to repeat the cycle. A bacterial surface protein, Act A, induces polymerization of actin but another, as yet unidentified bacterial factor, is required to control the formation of the polar tail and thereby enable directional movement through the cytoplasm. Salmonella flexneri uses very similar modes of phagosome disruption, actin-dependent movement, and cell to cell spread. As previously noted, the invasin IpaB lyses the phagosome. The Shigella protein IcsA mediates both actin deposition and formation of the polar tail.
Garcinia indica (Kokum) and Ilex aquifolium (European Holly)
Published in Azamal Husen, Herbs, Shrubs, and Trees of Potential Medicinal Benefits, 2022
Dicson Sheeja Malar, Mani Iyer Prasanth, Tewin Tencomnao, James Michael Brimson, Anchalee Prasansuklab
The leaf extracts of I. aquifolium were reported to exhibit antibacterial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Enterobacter aerogenes, Proteus vulgaris, Salmonella typhimurium, and anti-fungal activity against Candida albicans (Erdemoglu et al., 2009; do Nascimento et al., 2014). I. aquifolium extract also showed inhibition against Mycobacterium tuberculosis which might be due to the potential inhibition of the survival protein, the heat shock protein16.3 by the active compound UA (Erdemoglu et al., 2009; Jee et al., 2018). UA inhibits ATP production by interfering with the regulatory enzymes of glycolysis pathway, peptidoglycan synthesis pathways and exhibits antimicrobial activity against S. mutans UA159 (Park et al., 2018; Park et al., 2015). In methicillin-resistant Staphylococcus aureus UA treatment induced membrane disruption, interfered with protein translation, metabolic pathways of glycolysis, and elicited oxidative stress to exhibit antibacterial effect (Wang et al., 2016a). UA showed antibiofilm activity by affecting the virulence factors of L. monocytogenes and inhibited listeriolysin O activity (Kurek et al., 2014). Further, UA inhibits HIV-1 protease activity to attenuate the retroviral process of HIV (Quéré et al., 1996).
Bacteria Causing Gastrointestinal Infections
Published in K. Balamurugan, U. Prithika, Pocket Guide to Bacterial Infections, 2019
B. Vinoth, M. Krishna Raja, B. Agieshkumar
Fever is the prominent characteristic clinical feature, and diarrhea is usually watery. Only a few people develop bloody diarrhea. Other symptoms include headache, myalgia, nausea, and vomiting. Most are self-limited and resolve spontaneously, but few can develop dissemination and lead to more invasive illness. Diagnosing Listeria gastroenteritis is challenging because they require a highly selective culture medium. Hence, the laboratories should be intimated if Listeria is suspected. Serological method for detection of listeriolysin O antigen is available for retrospective diagnosis, and recently DNA-based methods are also available but are not routinely used. Antibiotics are not routinely recommended for uncomplicated illness; however, they are given to patients at high risk (e.g., those who are pregnant, immunocompromised, and older) during outbreaks and in cases with dissemination. The preferred antibiotics in uncomplicated cases are septran, ampicillin, or amoxicillin and in complicated cases, are aminoglycoside in combination with ampicillin or amoxicillin. These infections are best prevented by following strict food-safety measures.
Pyrrole-2-carboxylic acid inhibits biofilm formation and suppresses the virulence of Listeria monocytogenes
Published in Biofouling, 2023
Yuxi Yue, Kai Zhong, Yanping Wu, Hong Gao
In addition to biofilm, listeriolysin O (LLO), an important virulence factor of L. monocytogenes, contributes to pathogenicity and is considered to be a promising target to control L. monocytogenes. LLO, also known as a pore-forming toxin, is a Listeria-specific hemolysin (Osborne and Brumell 2017). The inhibitory influence of PCA on the hemolytic activity of L. monocytogenes was evaluated. As shown in Figure 4B, PCA treatment caused a decrement in hemolytic activity (p < 0.05). The bacterial culture supernatant without PCA addition displayed a high hemolysis rate of 93.95%. When exposed to PCA at 0.188, 0.375 and 0.750 mg ml−1, the hemolysis rate decreased to 78.74%, 70.05% and 57.12%, respectively. Even recently, similar findings that phenyllactic acid inactivated the hemolytic activity of L. monocytogenes have been reported (Jiang et al. 2022). LLO can bind to the cholesterol in the cell surface, causing membrane perforation and K+ fluxes (Vadia and Seveau 2014). LLO production allows L. monocytogenes to escape rapidly from the phagolysosome and facilitates the spread and replication of bacteria (Matereke and Okoh 2020). These results indicated that PCA presumably reduced the virulence of L. monocytogenes by disturbing production and secretion of LLO.
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).
Clinical management of women with listeriosis risk during pregnancy: a review of national guidelines
Published in Expert Review of Anti-infective Therapy, 2018
Lisa Pucci, Mario Massacesi, Giuseppina Liuzzi
For this reason, a serodiagnostic assay based on the detection of serum antibodies directed against listeriolysin O (LLO) has been repeatedly proposed [1,25,67]. LLO is a virulence factor of L. monocytogenes, is not found in other Listeria species [68], and has a pivotal role in the mechanism of infection of the pathogen. Moreover, LLO is also a target of the antilisterial immune response [69,70]. It has been consistently demonstrated that anti-LLO antibodies are reliable indicators of listeric infections both in humans and in animals [67,71–75].