Listeria monocytogenes, a ubiquitous foodborne pathogen, was recognized over 70 years ago. It is the source of the human disease listeriosis. The majority of Listeria monocytogenes that have been isolated from food product or human cases are of the serotypes ½ a, ½ b and 4b. Due to the recent outbreaks, recalls and deaths associated with Listeria monocytogenes in ready-to-eat meat products, the United States Department of Agriculture (USDA), Food Safety and Inspection Service (FSIS) on October 2, 2003 issued a directive for the control of Listeria monocytogenes on ready-to-eat products. The ready-to-eat food industry must impose a post-lethality treatment and/or growth inhibitor for Listeria monocytogenes on ready-to-eat products. The purpose of this study was to assess the use of different antimicrobial treatments for the inhibition of Listeria monocytogenes on the surface of food products. The utilization of natural ingredients such as cranberries as well as chemicals such as acidified sodium
The intracellular bacterial pathogen Listeria monocytogenes is shown to exploit efferocytosis-the process by which dead or dying cells are removed by phagocytosis-to promote cell-to-cell spread during infection. This study of the intracellular bacterial pathogen Listeria monocytogenes, a significant cause of foodborne illness, shows that it exploits the hosts efferocytosis system to promote cell-to-cell spread during infection. Efferocytosis is the process by which dead or dying cells are removed by phagocytosis and it relies in part on the receptors that bind to exofacial phosphatidylserine on the surface of cells or cellular debris following the loss of plasma membrane asymmetry. Listerial actin-based motility leads to the formation of protrusions at the cell surface of infected cells, eventually leading to uptake of bacteria by adjacent cells. These findings identify phosphatidylserine as a possible drug target in infections by L. monocytogenes and other bacteria using similar strategies of cell-to
Listeria Monocytogenes Listeria Spp Food Microbiology Fapas Proficiency Tests Biofront Technologies. LISTERIA MONOCYTOGENES/LISTERIA SPP. IN MILK POWDER Distribution Date: 07/03/2017 LISTERIA MONOCYTOGENES/LISTERIA SPP. IN CHICKEN Distribution Date: 11/27/2017 LISTERIA MONOCYTOGENES/LISTERIA SPP. IN BEEF Distribution Date: 01/29/2018 LISTERIA MONOCYTOGENES/LISTERIA SPP. IN SPONGE SWAB Distribution Date: 02/08/2018
The goal of Health Canadas Policy on Listeria monocytogenes, in Ready-to-Eat Foods (the Policy) is to protect the health of Canadian consumers, to provide guidance to industry and regulatory authorities regarding the verification and control of Listeria monocytogenes in Ready-to-Eat foods.
Listeria monocytogenes can adhere to different types of food contact surfaces within a food processing environment. Therefore, environmental sampling devices should be capable of detecting unacceptable contamination. In this study, a sponge-stick, foam spatula and an environmental swab were evaluated on their ability to detect low concentrations of L. monocytogenes on different types of food contact surfaces. A cocktail of four L. monocytogenes serotypes was inoculated with a concentration of 100 CFU/250 cm2 onto stainless steel (SS), high density polyethylene (HDPE) and rubber surfaces in a 250 cm2 area. Immediately after inoculation and after 1 h exposure, the surfaces were swabbed with the different swabbing devices. The results of the study show only minor differences in the ability of the swabbing devices to detect L. monocytogenes. All devices were capable to detect the contamination immediately after inoculation. However, when the surfaces were allowed to air-dry for 1 h, L. monocytogenes was
Human E-cadherin promotes entry of the bacterial pathogen Listeria monocytogenes into mammalian cells by interacting with internalin (InlA), a bacterial surface protein. Here we show that mouse E-cadherin, although very similar to human E-cadherin (85% identity), is not a receptor for internalin. By a series of domain-swapping and mutagenesis experiments, we identify Pro16 of E-cadherin as a residue critical for specificity: a Pro--|Glu substitution in human E-cadherin totally abrogates interaction, whereas a Glu--|Pro substitution in mouse E-cadherin results in a complete gain of function. A correlation between cell permissivity and the nature of residue 16 in E-cadherins from several species is established. The location of this key specificity residue in a region of E-cadherin not involved in cell-cell adhesion and the stringency of the interaction demonstrated here have important consequences not only for the understanding of internalin function but also for the choice of the animal model to be used
Although infection with the intracellular bacterium Listeria monocytogenes can result in severe illnesses such as sepsis and meningitis in immunocompromised people, a much more common outcome is control and clearance of the organism without serious malady. L. monocytogenes is able to infect common laboratory animals such as the mouse, immunologists have been able to dissect this host-pathogen interplay and elucidate the immune functions required to contain and eliminate L. monocytogenes infection. Importantly, the mouse model of L. monocytogenes infection has yielded discoveries that are not only specific to this host-pathogen interaction but also help define fundamental concepts of innate and adaptive immunity. The natural route of L. monocytogenes infection in humans is via the gut after consumption of contaminated food products. However, infection of mice in this manner requires an extremely large inoculum and often results in asynchronous systemic infections, which complicate experimental design.
TY - JOUR. T1 - Listeria monocytogenes isolates carrying virulence-attenuating mutations in internalin A are commonly isolated from ready-to-eat food processing plant and retail environments. AU - Van Stelten, A.. AU - Roberts, A. R.. AU - Manuel, C. S.. AU - Nightingale, K. K.. PY - 2016/10. Y1 - 2016/10. N2 - Listeria monocytogenes is a human foodborne pathogen that may cause an invasive disease known as listeriosis in susceptible individuals. Internalin A (InlA; encoded by inlA) is a virulence factor that facilitates crossing of host cell barriers by L. monocytogenes. At least 19 single nucleotide polymorphisms (SNPs) in inlA that result in a premature stop codon (PMSC) have been described worldwide. SNPs leading to a PMSC in inlA have been shown to be causally associated with attenuated virulence. L. monocytogenes pathogens carrying virulence-attenuating (VA) mutations in inlA have been commonly isolated from ready-to-eat (RTE) foods but rarely have been associated with human disease. This ...
Listeria monocytogenes is a bacterium that can cause illness when consumers eat refrigerated, ready-to-eat foods contaminated with this micro-organism. Eating foods contaminated with L. monocytogenes normally causes flu-like symptoms in healthy adults. This disease is more serious for elderly adults and adults with compromised immune systems and can cause menin-gitis. In pregnant women, the disease may cause spontaneous abortions or stillborn babies.. From July 1998 to January 1999, four U.S. companies recalled ready-to-eat meats after L. monocytogenes was found in their products. Two major recalls involved 30 million pounds each. According to the Centers for Disease Control, tainted meat traced to a Michigan plant was responsible for 16 deaths, six miscarriages and 100 illnesses. As a result of this outbreak, the U.S. Department of Agricultures Food Safety and Inspection Service (FSIS) addressed the problem of L. monocytogenes contamination in a directive published in the Federal Register in ...
TY - JOUR. T1 - An outbreak of an unusual strain of Listeria monocytogenes infection in North-East Scotland. AU - Okpo, Emmanuel. AU - Leith, Jayne. AU - Smith-Palmer, Alison. AU - Bell, John. AU - Parks, Duncan. AU - Browning, Fiona. AU - Byers, Lynn. AU - Corrigan, Helen. AU - Webster, Diana. AU - Karcher, Anne M. AU - Murray, Andrew. AU - Storey, Tom. N1 - Acknowledgements The authors would like to thank Kerry Parrott and Pauline Fuchs from the Aberdeen Scientific Services Laboratory (ASSL) for the analysis and testing of food and environmental samples. We also thank Corinne Amar, Craig Swift and Adedoyin Awofisayo from PHE Foodborne Pathogens Reference Services, London, for providing expert advice and molecular typing results in a timely manner. Funding No funding sources.. PY - 2015/11. Y1 - 2015/11. N2 - Listeria monocytogenes infection is an important cause of illness and hospitalization in vulnerable individuals. In the present study, we describe a community outbreak of Listeria ...
Listeriolysin O (LLO, hly-encoded) is a major virulence factor secreted by the pathogen Listeria monocytogenes. The amino acid sequence of LLO shows a high degree of similarity with that of ivanolysin O (ILO), the cytolysin secreted by the ruminant pathogen Listeria ivanovii. Here, it was tested whether ILO could functionally replace LLO by expressing the gene encoding ILO under the control of the hly promoter, in an hly-deleted strain of L. monocytogenes. It is shown that ILO allows efficient phagosomal escape of L. monocytogenes in both macrophages and hepatocytes. Moreover, expression of ILO is not cytotoxic and promotes normal intracellular multiplication. In vivo, the ILO-expressing strain can multiply and persist for several days in the liver of infected mice but is unable to survive in the spleen. This work underscores the key role played by the cytolysin in the virulence of pathogenic Listeria.
This book provides readers with the latest developments in Listeria Monocytogenes research. Topics covered include its growth in biofilms in the food industry; molecular mechanisms involved in the food-related subsistence of Listeria Monocytogenes; an epidemiological update and the control possibilities for outbreaks of L. Monocytogenes; how to control L. Monocytogenes biofilms on food contact surfaces; methods for killing activities of macrophages against L. Monocytogenes infection; and a review of some of the most exciting developments in the analysis of the interaction between L. Monocytogenes and the host GI tract ...
Listeria monocytogenes serotype 4a 30S ribosomal protein S19 (rpsS) datasheet and description hight quality product and Backed by our Guarantee
1. Maertens de Noordhout C, Devleesschauwer B, Angulo FJ, Verbeke G, Haagsma J, Kirk M, et al. The global burden of listeriosis: a systematic review and meta-analysis. Lancet Infect Dis. 2014;14(11):1073-82. doi: 10.1016/S1473-3099(14)70870-9 25241232. 2. Charlier C, Perrodeau É, Leclercq A, Cazenave B, Pilmis B, Henry B, et al. Clinical features and prognostic factors of listeriosis: the MONALISA national prospective cohort study. Lancet Infect Dis. 2017;17(5):510-9. doi: 10.1016/S1473-3099(16)30521-7 28139432. 3. Orsi RH, Bakker HC de., Wiedmann M. Listeria monocytogenes lineages: Genomics, evolution, ecology, and phenotypic characteristics. Int J Med Microbiol. 2011;301(2):79-96. doi: 10.1016/j.ijmm.2010.05.002 20708964. 4. Kamisango K, Saiki I, Tanio Y, Okumura H, Araki Y, Sekikawa I, et al. Structures and biological activities of peptidoglycans of Listeria monocytogenes and Propionibacterium acnes. J Biochem. 1982;92(1):23-33. doi: 10.1093/oxfordjournals.jbchem.a133918 6811573. 5. Brown S, ...
The Gram-positive human pathogen Listeria monocytogenes uses a wide range of virulence factors for its pathogenesis. The majority of its virulence genes are encoded on a 9-kb pathogenicity island and are controlled by the transcriptional activator PrfA. Expression of these genes is maximal at 37°C and minimal at 30°C in a mechanism involving an RNA thermosensor. This thesis brings up different aspects of RNA-mediated regulation, including regulatory RNA structures within coding mRNA controlling expression to 5-untranslated RNA (5´-UTR) that controls downstream genes (cis-acting) as well as small non-coding RNAs (ncRNAs) that bind other target RNA (trans-acting).. We investigated the importance of the coding region of the prfA-mRNA for its expression. Various lengths of prfA-mRNA were fused with reporter genes. Our finding suggested that the first 20 codons of prfA-mRNA were essential for efficient translation in Listeria monocytogenes. Translation of the shorter constructs was shown to be ...
Lien vers Pubmed [PMID] - 23737746. PLoS Pathog. 2013;9(5):e1003381. Listeria monocytogenes (Lm) is an invasive foodborne pathogen that leads to severe central nervous system and maternal-fetal infections. Lm ability to actively cross the intestinal barrier is one of its key pathogenic properties. Lm crosses the intestinal epithelium upon the interaction of its surface protein internalin (InlA) with its host receptor E-cadherin (Ecad). InlA-Ecad interaction is species-specific, does not occur in wild-type mice, but does in transgenic mice expressing human Ecad and knock-in mice expressing humanized mouse Ecad. To study listeriosis in wild-type mice, InlA has been "murinized" to interact with mouse Ecad. Here, we demonstrate that, unexpectedly, murinized InlA (InlA(m)) mediates not only Ecad-dependent internalization, but also N-cadherin-dependent internalization. Consequently, InlA(m)-expressing Lm targets not only goblet cells expressing luminally-accessible Ecad, as does Lm in humanized mice, ...
Listeria Monocytogenes: Its discovery and naming. Eben van Tonder 16 December 2017 Cape Town Introduction The discovery and naming of the Listeria monocytogenes are instructive with a very interesting South African connection and a controversy associated with it in that there is disagreement in terms of who is being honoured in the name. Monocytogenes The…
Listeria monocytogenes is the causative agent of listeriosis, an infection that gives rise to bacteremia and meningitis that can be propagated to humans via food contamination. The chicken-meat and derivatives processing industries are common sites of this pathogen, and the great challenge is in controlling this hazard to avoid economic and public health losses. A literature review on L. monocytogenes and implications to the chicken supply chain, poultry slaughterhouses, and public health was conducted. The review was compiled with the main papers published around the world in the last 15 years containing the key words Listeria monocytogenes, poultry, meat, chicken, broilers, and listeriosis, using the main publishers of online journals. The collected information was discussed and it was concluded that poultry can be asymptomatic carriers of L. monocytogenes and introduce contamination in slaughterhouses, which can become a persistent problem in poultry slaughterhouses due to its capacity to form
Listeria monocytogenes ATCC ® BAA-679D-5™ Designation: Genomic DNA from Listeria monocytogenes Strain EGDe TypeStrain=False Application: Enteric Research
In contrast to obligate intracellular pathogens that can remain in relatively stable host-associated environments, the soil-living bacterial pathogen Listeria monocytogenes has to sense and respond to physical and chemical cues in a variety of quite different niches. In particular, the bacterium has to survive the dramatic transition from its saprophytic existence to life within the host where nutritional stress, increased temperature, acidity, osmotic stress and the host defences present a new and challenging landscape. This review focuses on the sB and PrfA regulatory systems used by L. monocytogenes to sense the changing environment and implement survival mechanisms that help to overcome the disparate conditions within the host, but also to switch from a harmless saprophyte to an impressively effective pathogen.. ...
Of at least 400 Listeria phages, only a few have been characterized as having wide host range among listeriae and no phages have been isolated from the environment of food processing plants, where contamination of highly processed, ready to eat foods is likely to occur. To understand the ecology of listeriaphage and Listeria monocytogenes in processing plant environments, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey-processing plants in the United States. Nine of twelve isolated phages showed wide host range and the majority of L. monocytogenes of the serotype 4b complex (serotypes 4b, 4d, 4e) could be readily infected by these wide host range phages, but many isolates of other serotypes (1/2a or 3a, and 1/2b or 3b), which represented the majority of L. monocytogenes isolated from the environmental samples, were resistant to infection. L. monocytogenes epidemic clone II (ECII) has been responsible for two multistate outbreaks in the United ...
Oxaran, V.; Dittmann, K.Kiesbye.; Lee, S.H.I.; Chaul, Líza.Toubas.; Fernandes de Oliveira, C.Augusto.; Corassin, C.Humberto.; Alves, Vínia.Farias.; De Martinis, E.Cristina.Pereira.; Gram, L., 2018: Behavior of Foodborne Pathogens Listeria monocytogenes and Staphylococcus aureus in Mixed-Species Biofilms Exposed to Biocides
Listeria monocytogenes ATCC ® 19115D-5™ Designation: Genomic DNA from Listeria monocytogenes strain Li 2 TypeStrain=False Application:
Examination of food chain-derived Listeria monocytogenes strains of different serotypes reveals considerable diversity in inlA genotypes, mutability, and adaptation to cold temperatures.
Cold shock proteins (Csps) are multifunctional nucleic acid binding proteins used to regulate a wide range of gene expression responses in bacteria. We report here that Csps regulate the production of the pore-forming cytolysin listeriolysin (LLO) and hemolysis phenotypes in Listeria monocytogenes. A triple csp gene deletion mutant incapable of producing any Csps, as well as double csp gene deletion mutants only producing either CspA or CspD, caused less hemolysis and produced lower LLO concentration. On the other hand, another double csp gene deletion mutant that produces CspB retained hemolysis and LLO production levels that are similar to the parental wild-type strain. Transcription analysis showed that in absence of all three csp genes or cspB alone, L. monocytogenes cells have decreased levels of hly gene transcripts, which code for the synthesis of LLO proteins. A comparative examination of mRNA stability showed that hly transcripts were more rapidly degraded in L. monocytogenes triple csp ...
It is the investigators intention to investigate whether a specially designed vaccine, based on a genetically modified strain of the bacterium Listeria monocytogenes and called ADXS11-001 is safe to use and is able to boost the immune system of patients presenting with Human Papilloma Virus (HPV) associated oropharyngeal cancer (OPSCC). It is hoped that the vaccine will boost the immune system so that immune cells with cell killing properties are able to attack any cancer cells remaining after the patients have been treated. However, the vaccine is so novel the investigators are not sure whether it is able to do this and before they can answer that question in a larger group of patients they need to make sure that the vaccine is safe to use and has some effect on the immune system in the patients for whom they intend its ultimate use. In a previous study, patients with incurable cervix cancer which is caused by the same virus, were vaccinated with ADXS11-001. Although all patients vaccinated ...
Listeria Monocytogenes: Factory Cleaning, Thermal Inactivation and Acid Tolerance Response By Eben van Tonder 6 January 2018 (Update: 2/2018) Summary In light of the unprecedented listeria outbreak in South Africa, we examine processes and procedures at the cutting plant, factory cleaning, thermal inactivation and acid tolerance response of Listeria monocytogenes. We question everything we do…
This study shows that neutrophils are critical for combating experimental systemic infections of mice by the bacterial pathogens Listeria monocytogenes, Salmonella typhimurium, and Yersinia enterocolitica. It shows that mice rendered neutropenic by treatment with the granulocyte-depleting monoclonal antibody RB6-8C5 are far more susceptible than immunocompetent mice to infection with each of these three pathogens. Compared to immunocompetent mice, neutropenic mice exhibit several defects in their antibacterial capabilities. Firstly, the immediate inactivation of Listeria, Salmonella, or Yersinia that initially implants in the livers and spleens that occurs in immunocompetent mice is abolished in these organs in neutropenic mice. Secondly, unlike immunocompetent mice, neutropenic mice neither control the subsequent proliferation of the inoculated bacteria in the livers and spleens nor prevent dissemination of infection to other organs. Thirdly, mice rendered neutropenic develop a generalized ...
1. Murray, E.G.D., R.A. Webb, and M.B.R. Swann. 1926. A disease of rabbits characterized by large mononuclear leucocytosis caused by a hitherto undescribed bacillus Bacterium monocytogenes. J. Path. Bact.; 29:407-0439.. 2. Monk, J.D., R.S. Clavero, L.R. Beuchat, M.P. Doyle and R.E. Brackett. 1994. Irradiation inactivation of Listeria monocytogenes and Staphylococcus aureus in low- and high-fat, frozen and refrigerated ground beef. J. Food Prot.; 57:969-974.. 3. Wehr, H.M. 1987. Listeria monocytogenes - a current dilemma special report. J. Assoc. Off. Anal. Chem.; 70:769-772.. 4. Bremer, P.J., and C.M. Osborne. 1995. Thermal-death times of Listeria monocytogenes in green shell mussels (Perna canaliculus) prepared for hot smoking. J. Food Prot.; 58:604-608.. 5. Grau, F.H., and P.B. Vanderlinde. 1992. Occurrence, numbers, and growth of Listeria monocytogenes on some vacuum-packaged processed meats. J. Food Prot.; 55:4-7.. 6. Patel, J.R., C.A. Hwang, L.R. Beuchat, M.P. Doyle, and R.E. Brackett. ...
The aim of this study was to determine the presence of Listeria spp. Immunoassay method in samples of fresh cow cheese, and from the obtained positive samples with Horizontal method for the detection and enumeration of cells and biochemical prove the presence of species Listeria monocytogenes. Also is need to compare the results obtained by Immunoassay method and by Horizontal method. It research involve a total of 30 randomly selected samples of fresh cow cheese that are available in Zagreb on markets. The results obtained are compared with the criteria set forth in the applicable legislation of the Republic of Croatian. In one of the 30 samples is showed presence of Listeria monocytogenes, and in three samples was determined by the presence of Listeria innocua ...
Cholesterol-dependent cytolysins (CDCs) are protein toxins that originate from Gram-positive bacteria and contribute substantially to their pathogenicity. CDCs bind membrane cholesterol and build prepores and lytic pores. Some effects of the toxins are observed in non-lytic concentrations. Two pathogens, Streptococcus pneumoniae and Listeria monocytogenes, cause fatal bacterial meningitis, and both produce toxins of the CDC family-pneumolysin and listeriolysin O, respectively. It has been demonstrated that pneumolysin produces dendritic varicosities (dendrite swellings) and dendritic spine collapse in the mouse neocortex, followed by synaptic loss and astrocyte cell shape remodeling without elevated cell death. We utilized primary glial cultures and acute mouse brain slices to examine the neuropathological effects of listeriolysin O and to compare it to pneumolysin with identical hemolytic activity. In cultures, listeriolysin O permeabilized cells slower than pneumolysin did but still initiated non
Five grams of seafood products were inoculated with one to 500 viable or 10(9) heat-killed cells of Listeria monocytogenes. The presence of the pathogen was detected by the polymerase chain reaction (PCR) with primers specific for fragments of the listeriolysin O (hly) gene (two sets) and for the invasion-associated protein (iap) gene (one set). For DNA preparation, boiling, either alone or in combination with lysozyme and proteinase K treatment, was not always sufficient to lyse L. monocytogenes, while treatment with Triton X-100 produced consistently good DNA suitable for amplification. To avoid false-negative and false-positive results, 48 h incubations were necessary and a subculturing step after an initial 24 h incubation greatly improved the results. The primers that amplified regions of the listeriolysin O gene gave clearer and stronger products than primers for the invasion-associated protein gene. Using this method we were able to detect one to five L. monocytogenes cells in 5 g of ...
Five grams of seafood products were inoculated with one to 500 viable or 10(9) heat-killed cells of Listeria monocytogenes. The presence of the pathogen was detected by the polymerase chain reaction (PCR) with primers specific for fragments of the listeriolysin O (hly) gene (two sets) and for the invasion-associated protein (iap) gene (one set). For DNA preparation, boiling, either alone or in combination with lysozyme and proteinase K treatment, was not always sufficient to lyse L. monocytogenes, while treatment with Triton X-100 produced consistently good DNA suitable for amplification. To avoid false-negative and false-positive results, 48 h incubations were necessary and a subculturing step after an initial 24 h incubation greatly improved the results. The primers that amplified regions of the listeriolysin O gene gave clearer and stronger products than primers for the invasion-associated protein gene. Using this method we were able to detect one to five L. monocytogenes cells in 5 g of ...
A total of 486 Listeria monocytogenes isolates originating from 17 Finnish food processing plants (representing meat, poultry, fish, and dairy production) were collected and typed by automated ribotyping using EcoRI as the restriction enzyme. The isolates were divided into 16 different ribotypes (RTs). Some of these isolates (121), representing all EcoRI types and 16 food plants, were subjected to ribotyping with the PvuII enzyme, to pulsed-field gel electrophoresis (PFGE) typing with AscI and SmaI restriction enzymes, and to serotyping with O-antigen antisera. Nineteen ribotypes were generated with PvuII, 42 macrorestriction patterns were generated with AscI and 24 with SmaI, and three serotypes were generated with antisera. When the results were combined, the overall number of RTs was 23, and that of the PFGE types was 46. Thus, the overall discrimination power of PFGE was higher (discrimination index [DI] 0.966) than that of ribotyping (DI 0.906). The most common serotype (90.1% of the isolates) was
Listeria monocytogenes causes foodborne disease in humans that ranges in severity from mild, self‐limiting gastroenteritis to life‐threatening systemic infections of the blood, brain, or placenta
Listeriolysin O (LLO) is a major virulence factor secreted by the pathogenic Listeria monocytogenes and acts as pore-forming cytolysin. Based on sequence similarities between LLO and perfringolysin (PFO), the cytolysin from Clostridium perfringens of known crystallographic structure, two truncated LLO proteins were produced: LLO-d123, comprising the first three predicted domains, and LLO-d4, the last C-terminal domain. The two proteins were efficiently secreted into the culture supernatant of L. monocytogenes and were able to bind to cell membranes. Strikingly, when expressed simultaneously, the two secreted domains LLO-d123 and LLO-d4 reassembled into a haemolytically active form. Two in-frame linker insertions were generated in the hinge region between the d123 and d4 domains. In both cases, the insertion created a major cleavage site for proteolytic degradation and abolished cytolytic activity, which might suggest that the region connecting d123 and d4 participates in the interaction between the two
Listeria monocytogenes is a foodborne pathogen and is the causative agent of listeriosis among humans and animals. The draft genome sequence of L. monocytogenes DPC6895, a serotype 1/2b strain isolated from the raw milk of a cow with subclinical bovine mastitis, is reported.
Foster Farms, a Farmerville, La., establishment, is recalling approximately 39,747 pounds of frozen pre-cooked chicken products due to possible contamination with Listeria monocytogenes.
Bacterial pathogens dramatically affect host cell transcription programs for their own profit, however the underlying mechanism in most cases remain elusive. While investigating the effects of listeria monocytogenes on histone modifications, we discovered a new transcription regulatory machanism by which the expression of genes is repressed, during infection. Upon infection by L. monocytogenes, the secret virulence factor, InlB, binds the c-Met receptor and activates signaling through PI3K/Akt. This signaling platform is necessary for causing the relocalization of the histone deacetylase, SIRT2, to the nucleus and associating to chromatin.In characterizing the mechanism governing SIRT2 nuclear relocazing during infection, our results have demonstrated that SIRT2 undergoes a post-translational modification. SIRT2 undergoes dephosphorylation at a novel N-terminal phospho-site. SIRT2 is recruiter to the transcription star sites of genes repressed during inection leading to H3K18 deacetylation and
Although rates of listeriosis are low in comparison to other foodborne pathogenic illnesses, listeriosis poses a significant risk to human health as the invasive form can have a mortality rate as high as 30%. Food processors, especially those who produce ready-to-eat products, need to be vigilant against Listeria monocytogenes, the causative pathogen of listeriosis, and as such, the occurrence of L. monocytogenes in food and in the food processing environment needs to be carefully monitored. To examine the prevalence and patterns of contamination in food processing facilities in Ireland, 48 food processors submitted 8 samples every 2 months from March 2013 to March 2014 to be analyzed for L. monocytogenes. No positive samples were detected for 38% of the processing facilities tested. Isolates found at the remaining 62% of facilities were characterized by serotyping and Pulsed Field Gel Electrophoresis (PFGE). A general L. monocytogenes prevalence of 4.6% was seen in all samples analyzed with similar
Listeria monocytogenes is an important foodborne pathogen that can cause serious illness in immunocompromised individuals, pregnant women, the elderly, and newborns. The aim of this study was to: (i) evaluate the prevalence and contamination level [most probable number (MPN)] of L. monocytogenes in 567 retail raw foods (fishery products, n = 154; raw/fresh meat, n = 123; frozen foods, n = 110; edible fungi, n = 108; vegetables, n = 72) collected from South China and (ii) to gain further knowledge on the phenotype and genotype distributions of this important foodborne pathogen. Approximately 22% of the samples were positive for L. monocytogenes. The contamination levels were between 0.3 and 10 MPN/g in 75.0%, between 10 and 100 MPN/g in 11.0% and less than 100 MPN/g in 14.0% of the countable samples. Five serogroups were identified among the 177 foodborne L. monocytogenes isolates, with 1/2a-3a (42.4%) and 1/2b-3b (26.0%) serogroups being the most dominant. Serogroups I.1 and II.2 were only found in the
The inflammasome pathway functions to regulate caspase-1 activation in response to a broad range of stimuli. Caspase-1 activation is required for the maturation of the pivotal pro-inflammatory cytokines of the pro-IL-1beta family. In addition, caspase-1 activation leads to a certain type of cell death known as pyroptosis. Activation of the inflammasome has been shown to play a critical role in the recognition and containment of various microbial pathogens, including the intracellularly replicating Listeria monocytogenes; however, the inflammasome pathways activated during L. monocytogenes infection are only poorly defined. Here, we demonstrate that L. monocytogenes activates both the NLRP3 and the AIM2 inflammasome, with a predominant involvement of the AIM2 inflammasome. In addition, L. monocytogenes-triggered cell death was diminished in the absence of both AIM2 and NLRP3, and is concomitant with increased intracellular replication of L. monocytogenes. Altogether, these data establish a role for DNA
Background and Objective: Listeria monocytogenes is an important food-borne intracellular pathogen which can transmit to human through contaminated foods and causing meningitis, meningoencephalitis and abortion. This study was done to determine the frequency, antimicrobial susceptibility and serotyping of Listeria monocytogenes isolated from food samples in Tehran, Iran. Methods: This descriptive ...
Rabbit polyclonal antibody raised against Listeria monocytogenes. Native from Listeria monocytogenes (ATCC #43251). (PAB14003) - Products - Abnova
Listeria monocytogenes continues to be a major foodborne pathogen that causes food poisoning and sometimes death in immunosuppressed people and abortion in pregnant women. Nanoparticles have recently drawn attentions for use in immunomagnetic separation techniques due to their greater surface area/volume ratio and better stability against sedimentation in the absence of a magnetic field. Interdigitated microelectrodes and microfluidics make material transfer more efficient and biological/chemical interaction between the surface and solution phase much quicker. Magnetic nanoparticles (Fe3O4) with a 30 nm diameter were functionalized with rabbit anti-L. monocytogenes antibodies via biotin-streptavidin bonds and then amalgamated with target bacterial cells to capture them during a 2 h immunoreaction. A magnetic field was applied to capture the nanoparticle-L. monocytogenes complexes and the supernatant was removed. After a washing step, L. monocytogenes was separated from a food sample and could be ready
Listeriolysin O (LLO) is a hemolysin produced by the bacterium Listeria monocytogenes, the pathogen responsible for causing listeriosis. The toxin may be considered a virulence factor, since it is crucial for the virulence of L. monocytogenes. Listeriolysin O is a non-enzymatic, cytolytic, thiol-activated, cholesterol-dependent, pore-forming toxin protein; hence, it is activated by reducing agents and inhibited by oxidizing agents. However, LLO differs from other thiol-activated toxins, since its cytolytic activity is maximized at a pH of 5.5. By maximizing activity at a pH of 5.5, LLO is selectively activated within the acidic phagosomes (average pH ~ 5.9) of cells that have phagocytosed L. monocytogenes. After LLO lyses the phagosome, the bacterium escapes into the cytosol, where it can grow intracellularly. Upon release from the phagosome, the toxin has reduced activity in the more basic cytosol. Hence, LLO permits L. monocytogenes to escape from phagosomes into the cytosol without damaging ...
The acquisition of pathogen-derived antigen by dendritic cells (DCs) is a key event in the generation of cytotoxic CD8(+) T cell responses. In mice, the intracellular bacterium Listeria monocytogenes is directed from the blood to splenic CD8α(+) DCs. We report that L. monocytogenes rapidly associated with platelets in the bloodstream in a manner dependent on GPIb and complement C3. Platelet association targeted a small but immunologically important portion of L. monocytogenes to splenic CD8α(+) DCs, diverting bacteria from swift clearance by other, less immunogenic phagocytes. Thus, an effective balance is established between maintaining sterility of the circulation and induction of antibacterial immunity by DCs. Other gram-positive bacteria also were rapidly tagged by platelets, revealing a broadly active shuttling mechanism for systemic bacteria. ...
by Vetscite. Scientists at Umeå Centre for Microbial Research (UCMR) have discovered chemical compounds which are able to attenuate the virulence of the bacterial human pathogen Listeria monocytogenes. Their findings are published today in the high impact journal Cell Chemical Biology.. The dramatic increase of antibiotic resistance makes new antimicrobial strategies necessary. The researchers at Umeå University in Sweden are studying an alternative approach, to inhibit the disease capacity (virulence) of bacteria but not their viability. Compared with traditional antibiotics, which often kill the bacteria, the risk of resistance development in disarmed bacteria is lower, since their survival does not depend on resistance against the new drug.. A Listeria infection can be very severe, particularly among patients such as elderly, infants, immunocompromised or pregnant women. Although disease occurrence is relatively low, Listerias severe and sometimes fatal health consequences make it among ...
The main aim of this study was to see if the antilisterial action of lyophilized cell-adsorbed bacteriocin from Lactobacillus curvatus CWBI-B28 might be reinforced by sim..
In several low-GC-content gram-positive bacteria, σB has been recognized as a general stress-responsive sigma factor. This alternative sigma factor contributes to the ability of organisms such as Listeria monocytogenes, Bacillus subtilis, and Staphylococcus aureus to survive under environmental and energy stress conditions (4, 10, 18, 19, 65).σ B also contributes to biofilm formation in S. aureus and Staphylococcus epidermidis (37, 55). Biofilm formation may further enhance the survival of these organisms under conditions of environmental stress.. In L. monocytogenes, a food-borne pathogen capable of causing mild to severe infections in humans,σ B confers stress resistance (e.g., under acid stress and osmotic stress) and contributes to pathogenesis. To illustrate, an L. monocytogenes σB null mutant survives less well than the wild-type parent at low pH (pH 2.5) and in a murine infection model (45, 67).σ B has been demonstrated to contribute to transcription of prfA, which encodes the ...