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surveillance for listeria monocytogenes and listeriosis, 1995-2004.canadian cases and outbreaks of illness caused by listeria monocytogenes between 1995 and 2004 were assessed. isolates (722 total) were characterized by serotyping, and pulsed-field gel electrophoresis (pfge) was performed to provide a means of detecting case clusters. rates of listeriosis remained fairly consistent during the period of study, and patient characteristics were similar to those seen in studies of other populations. most isolates were obtained from blood and cerebrospinal fluid, al ...201019818199
development of an oligonucleotide-based microarray to detect multiple foodborne pathogens.escherichia coli o157:h7, salmonella enterica, listeria monocytogenes and campylobacter jejuni are considered important pathogens causing the most food-related human illnesses worldwide. current methods for pathogen detection have limitations in the effectiveness of identifying multiple foodborne pathogens. in this study, a pathogen detection microarray was developed using various 70-mer oligonucleotides specifically targeting the above pathogens. to reduce the cost of detection, each microarray ...201019833198
mycobacterium avium subsp. paratuberculosis (map) as a modifying factor in crohn's disease.crohn's disease (cd) is a multifactorial syndrome with genetic and environmental contributions. mycobacterium avium subspecies paratuberculosis (map) has been frequently isolated from mucosal tissues of patients with cd but the cellular immune response to this bacterium has been poorly described. our aim was to examine the influence of map on t-cell proliferation and cytokine responses in patients with inflammatory bowel disease (ibd).201019824071
an enzyme-amplified amperometric dna hybridisation assay using dna immobilised in a carboxymethylated dextran film anchored to a graphite surface.this report describes a simple methodology for preparation of an enzyme-amplified amperometric dna hybridisation assay using solution-phase ferrocenemethanol mediation of glucose oxidase oxidation of glucose. the recognition layer consists of amine-terminated ssdna (designed for binding of the sequence ssra gene of listeria monocytogenes) bound within a carboxymethylated dextran film that is anchored to a graphite electrode. anchoring sites are provided by electrochemical grafting of an arylamin ...201019828307
microbiological quality and safety of raw milk and soft cheese and detection of autochthonous lactic acid bacteria with antagonistic activity against listeria monocytogenes, salmonella spp., and staphylococcus aureus.this study aimed to characterize the microbiological quality and safety of raw milk and soft cheese, verifying possible associations between microbial populations, and the detection of lactic acid bacteria (lab) with antagonistic activity against foodborne pathogens. raw milk (n = 36) and soft cheese (n = 18) samples were collected and submitted for the analysis of mesophilic aerobes, total coliforms, escherichia coli, lab, coagulase-positive staphylococcus (cps), listeria monocytogenes, and sal ...201019839761
in vivo activities of recombinant divercin v41 and its structural variants against listeria monocytogenes.recombinant divercin rv41 (dvnrv41) and its structural variants were used in this study to assess their antilisterial activities in vivo in mice challenged intravenously with listeria monocytogenes egde. treatment with dvnrv41 before and after infection permitted a conclusion as to the capacities of this peptide to retain activity and reduce growth of l. monocytogenes egde. moreover, the use of structural variants for the first time in vivo and the reductions of their activities confirmed the im ...201019841145
pediocin production in milk by pediococcus acidilactici in co-culture with streptococcus thermophilus and lactobacillus delbrueckii subsp. bulgaricus.the production of pediocin in milk by pediococcus acidilactici was evaluated in co-culture with the dairy fermentation cultures streptococcus thermophilus and lactobacillus delbrueckii ssp. bulgaricus. the cultures were tested singly and in different combinations in milk (0 or 2% fat content) during incubation at 40 degrees c for up to 10 h. cell-free milk samples taken every 60 min were tested for bacteriocin activity against listeria monocytogenes. pediocin activity was not detectable when p. ...201019844751
the in vitro antibiofilm activity of selected culinary herbs and medicinal plants against listeria monocytogenes.the antibiofilm activity of extracts obtained from selected herbs, spices, beverages and commercially important medicinal plants was investigated on listeria monocytogenes.201019874481
the use of chromogenic bacteria as coloured substitutes for pathogens: a simple strategy during design and development of a new method for sample pretreatment.in the present study, chromogenic (red) bacteria were used to simulate actual target bacteria during set-up and optimization of an isolation process of bacteria, designed for food samples. isolation of bacteria from food in the context of molecular biological detection of food pathogens is a multistep process. development of such a separation method requires continuous monitoring of the location of the presumable targets in the sample tubes. therefore, red-coloured pigmented bacteria were used a ...201019874486
assessment of survival of listeria monocytogenes, salmonella infantis and enterococcus faecalis artificially inoculated into experimental waste or compost.to evaluate survival of pathogenic strains, listeria monocytogenes and salmonella infantis and a sanitation indicator enterococcus faecalis in composts at different stages of the composting process and during storage.201019878526
influence of sublethal concentrations of common disinfectants on expression of virulence genes in listeria monocytogenes.listeria monocytogenes is a food-borne human pathogen that causes listeriosis, a relatively rare infection with a high fatality rate. the regulation of virulence gene expression is influenced by several environmental factors, and the aim of the present study was to determine how disinfectants used routinely in the food industry affect the expression of different virulence genes in l. monocytogenes when added at sublethal concentrations. an agar-based assay was developed to screen the effect of d ...201019897753
galleria mellonella as a model system for studying listeria pathogenesis.essential aspects of the innate immune response to microbial infection are conserved between insects and mammals. this has generated interest in using insects as model organisms to study host-microbe interactions. we used the greater wax moth galleria mellonella, which can be reared at 37 degrees c, as a model host for examining the virulence potential of listeria spp. here we report that galleria is an excellent surrogate model of listerial septic infection, capable of clearly distinguishing be ...201019897755
survival of listeria monocytogenes in simulated gastrointestinal system and transcriptional profiling of stress- and adhesion-related genes.food ingestion is the major route of exposure to the important human pathogen listeria monocytogenes. an in vitro gastrointestinal model was used to (1) compare the survival rates of l. monocytogenes strains of serotypes 1/2a, 1/2c, and 4b; and (2) examine the transcription of stress- and adhesion-related genes after exposure to the conditions similar to those encountered in the mouth, stomach, and small intestine. none of the l. monocytogenes strains investigated could survive in the gastric ju ...201019899961
wild boars as an important reservoir for foodborne pathogens.one hundred fifty-three wild boars shot in the canton of geneva, switzerland, were studied for the occurrence of foodborne pathogens. tonsils and fecal samples of the animals were examined using real-time polymerase chain reaction, enzyme-linked fluorescent immunoassay, and cultural methods. the detection rate of salmonella spp., yersinia enterocolitica, yersinia pseudotuberculosis, stx-positive escherichia coli, and listeria monocytogenes was 12%, 35%, 20%, 9%, and 17%, respectively, when tonsi ...201019899962
ligand-mediated dimerization of the met receptor tyrosine kinase by the bacterial invasion protein inlb.the listeria monocytogenes surface protein inlb mediates bacterial invasion into host cells by activating the human receptor tyrosine kinase met. so far, it is unknown how inlb or the physiological met ligand hepatocyte growth factor/scatter factor causes met dimerization, which is considered a prerequisite for receptor activation. we determined two new structures of inlb, revealing a recurring, antiparallel, dimeric arrangement, in which the two protomers interact through the convex face of the ...201019900460
tetraspanin cd81 is required for listeria monocytogenes invasion.listeria monocytogenes is an intracellular bacterial pathogen that invades epithelial cells by subverting two cellular receptors, e-cadherin and met. we recently identified type ii phosphatidylinositol 4-kinases alpha and beta (pi4kiialpha and pi4kiibeta) as being required for bacterial entry downstream of met. in this work, we investigated whether tetraspanins cd9, cd63, and cd81, which figure among the few described molecular partners of pi4kiialpha, function as molecular adaptors recruiting p ...201019901060
listeria monocytogenes does not survive ingestion by acanthamoeba polyphaga.listeria monocytogenes is a ubiquitous bacterium capable of infecting humans, particularly pregnant women and immunocompromised individuals. although the intracellular invasion and pathogenesis of listeriosis in mammalian tissues has been well studied, little is known about the ecology of l. monocytogenes , and in particular the environmental reservoir for this bacterium has not been identified. this study used short-term co-culture at 15, 22 and 37 degrees c to examine the interaction of l. mon ...201019892759
the sos response of listeria monocytogenes is involved in stress resistance and mutagenesis.the sos response is a conserved pathway that is activated under certain stress conditions and is regulated by the repressor lexa and the activator reca. the food-borne pathogen listeria monocytogenes contains reca and lexa homologues, but their roles in listeria have not been established. in this study, we identified the sos regulon in l. monocytogenes by comparing the transcription profiles of a wild-type strain and a deltareca mutant strain after exposure to the dna-damaging agent mitomycin c. ...201019892760
oleanolic acid and ursolic acid affect peptidoglycan metabolism in listeria monocytogenes.the plant pentacyclic triterpenoids, oleanolic and ursolic acids, inhibit the growth and survival of many bacteria, particularly gram-positive species, including pathogenic ones. the effect of these compounds on the facultative human pathogen listeria monocytogenes was examined. both acids affected cell morphology and enhanced autolysis of the bacterial cells. autolysis of isolated cell walls was inhibited by oleanolic acid, but the inhibitory activity of ursolic acid was less pronounced. both c ...201019894138
bioactive alginate coatings to control listeria monocytogenes on cold-smoked salmon slices and fillets.the relatively high incidence of listeria monocytogenes in cold smoked salmon (css) is of concern as css is a ready-to-eat product. no post-processing measures are currently available to control this pathogen in css. the objective of this study was to develop an effective antimicrobial edible coating containing organic salts to control the growth of l. monocytogenes in css slices and fillets. an in-house made formulation consisting of sodium lactate (sl, 0-2.4%) and sodium diacetate (sd, 0-0.25% ...201019861230
multilocus sequence typing of outbreak-associated listeria monocytogenes isolates to identify epidemic clones.listeria monocytogenes is a foodborne pathogen found in a wide variety of environments. subtype characterization of l. monocytogenes isolates from listeriosis outbreaks that have occurred over the last three decades has suggested that a number of outbreaks were caused by a small number of l. monocytogenes epidemic clones (ecs). in this study we compared the prevalence, ecology, and phylogenetic position of outbreak-associated isolates and non-outbreak-associated isolates to probe the evolutionar ...201019911921
re-evaluation, optimization, and multilaboratory validation of the pulsenet-standardized pulsed-field gel electrophoresis protocol for listeria monocytogenes.the pulsenet methods development and validation laboratory began a re-evaluation of the standardized pulsed-field gel electrophoresis (pfge) protocols with the goal of optimizing their overall performance and robustness. herein, we describe a stepwise evaluation of the pulsenet-standardized pfge protocol for listeria monocytogenes that led to the modification of several steps which significantly improved the overall appearance and reproducibility of the resulting pfge data. these improvements in ...201019911934
pregnancy does not deter the development of a potent maternal protective cd8+ t-cell acquired immune response against listeria monocytogenes despite preferential placental colonization.listeria monocytogenes (lm) preferentially colonizes the placenta and causes fetal loss and systemic disease during pregnancy. as systemic cd8+ t-cell memory is critical in controlling lm infection, we addressed the issue as to whether it is modulated during pregnancy.201019912156
quantification of listeria monocytogenes in minimally processed leafy vegetables using a combined method based on enrichment and 16s rrna real-time pcr.modern lifestyle markedly changed eating habits worldwide, with an increasing demand for ready-to-eat foods, such as minimally processed fruits and leafy greens. packaging and storage conditions of those products may favor the growth of psychrotrophic bacteria, including the pathogen listeria monocytogenes. in this work, minimally processed leafy vegetables samples (n = 162) from retail market from ribeirão preto, são paulo, brazil, were tested for the presence or absence of listeria spp. by the ...201019913686
inactivation of escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri on spinach leaves by x-ray.several recent foodborne disease outbreaks associated with leafy green vegetables, including spinach, have been reported. x-ray is a non-thermal technology that has shown promise for reducing pathogenic and spoilage bacteria on spinach leaves. inactivation of inoculated escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri on spinach leaves using x-ray at different doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kgy) was studied. the effect of x-ray on col ...201019913687
evaluation of an enterocin as-48 enriched bioactive powder obtained by spray drying.enterocin as-48 is a cationic cyclic bacteriocin produced by enterococcus faecalis with broad bactericidal activity. currently we are assaying the efficacy of as-48 as biopreservative in foods. in this work we have applied the spray drying process to different as-48 liquid samples to obtain active dried preparations. we have also assayed different methods, heat, uv irradiation and filtration, to inactivate/remove the as-48 producer cells from the samples. best results were obtained for the sampl ...201019913693
sodium lactate, sodium diacetate and pediocin: effects and interactions on the thermal inactivation of listeria monocytogenes on bologna.the effects and interactions of temperature (56.3-60 degrees c), sodium lactate (sl; 0-4.8%), sodium diacetate (sd; 0-0.25%) and pediocin (0-10,000 au) on listeria monocytogenes on bologna were studied and a predictive inactivation model was developed. bologna was manufactured with different sl/sd concentrations in the formulation, dipped in pediocin solution and treated at different temperatures using combinations of parameters determined by central composite design. d-values were calculated an ...201019913694
amplified fragment length polymorphism and multi-locus sequence typing for high-resolution genotyping of listeria monocytogenes from foods and the environment.standardized tools for typing listeria monocytogenes isolates are required in epidemiological surveys investigating food-borne disease outbreaks and in the food-processing environment to identify the sources of contamination and routes by which the organisms are spread. in this survey amplified fragment length polymorphism (aflp) and multi-locus sequence typing (mlst) have been used to study 103 l. monocytogenes isolates from food and environmental sources. a total of 62 aflp types and 66 mlst s ...201019913699
effects of x-ray radiation on escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri inoculated on shredded iceberg lettuce.the main goal of this investigation was to study the efficacy of x-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kgy) on inoculated escherichia coli o157: h7, listeria monocytogenes, salmonella enterica and shigella flexneri on shredded iceberg lettuce. the second goal was to study the effect of x-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 degrees c for 30 days. treatment with 1.0 kgy x-ray significantly reduced the population o ...201019913700
fate of listeria monocytogenes during freezing, thawing and home storage of frankfurters.little information is available regarding the fate of listeria monocytogenes during freezing, thawing and home storage of frankfurters even though recent surveys show that consumers regularly store unopened packages in home freezers. this study examined the effects of antimicrobials, refrigerated storage, freezing, thawing method, and post-thawing storage (7 degrees c) on l. monocytogenes on frankfurters. inoculated (2.1 log cfu/cm(2)) frankfurters formulated without (control) or with antimicrob ...201019913705
effect of nanovesicle-encapsulated nisin on growth of listeria monocytogenes in milk.commercial nisin was encapsulated in nanovesicles (mean diameter 140 nm) prepared from partially purified soy lecithin. nisin-loaded liposomes and unencapsulated (free) nisin were initially tested in bhi medium and skim milk inoculated with listeria monocytogenes and incubated for 48 h at 30 degrees c. at such abuse temperature conditions, free nisin showed better inhibitory than the liposomal counterparts. subsequently, the effect of encapsulated or free nisin was evaluated in combination with ...201019913710
polymorphism of acta gene is not related to in vitro virulence of listeria monocytogenes.listeria monocytogenes is a foodborne pathogen which is able to cause serious disease both in humans and in animals. several studies have demonstrated variations in the levels of virulence among l. monocytogenes strains. invasion and growth ability of l. monocytogenes into cultured cells have been used to evaluate its pathogenicity. in particular, invasiveness and growth ability have been typically investigated using hela cell line. this study aimed to provide further insights on the virulence p ...201019913932
microbiological analysis of composts produced on south carolina poultry farms.the purpose of this study was to determine whether the methods used in compost operations of small and medium-sized poultry farms resulted in the production of an amendment free of foodborne pathogens.201019922596
defensin from disk abalone haliotis discus discus: molecular cloning, sequence characterization and immune response against bacterial infection.gene-encoded antimicrobial peptides (amps) serve a major role in host defense systems against pathogens. in this study, cdna of a new mollusk defensin was identified from a normalized cdna library constructed from whole tissues of disk abalone. abalone defensin peptide (pro-defensin) has a 198-bp coding sequence comprised of a putative 66 amino acids with a mature defensin consisting of 48 amino acid residues. the presence of an invertebrate defensin family domain, an arrangement of six cysteine ...201019922800
nisin-induced expression of pediocin in dairy lactic acid bacteria.to test whether a single vector, nisin-controlled expression (nice) system could be used to regulate expression of the pediocin operon in streptococcus thermophilus, lactococcus lactis subsp. lactis and lactobacillus casei.201019929951
comparison of conventional and molecular methods for the routine confirmation of listeria monocytogenes in milk products produced domestically in croatia.conventional methods for the identification of listeria in foodstuffs are generally cumbersome and time consuming. the use of primary enrichment in half strength fraser broth and the use of palcam agar were assessed in comparison with api listeria and polymerase chain reaction (pcr) for their ability to accurately detect and confirm the presence of list. monocytogenes in milk products. the aim of our work was to detect list. monocytogenes in domestic unpasteurised milk, fresh cheese and cream of ...201019930757
quantification of host-microbe interactions by automated fluorescence microscopy.we describe an automated fluorescence microscopy-based assay that quantifies the invasion of mammalian cells by intracellular pathogens. pathogens associated with host cell surfaces, intracellular pathogens and mammalian cells are directly counted based on their specific fluorescent labeling. such approach utilizes automated image acquisition and processing, and is thus ideally suited for high-throughput analyses. this method was validated using listeria monocytogenes as a model intracellular pa ...201019931271
effect of growth and recovery temperatures on pressure resistance of listeria monocytogenes.experimental conditions can affect the outcome of bacterial stress-tolerance assays. growth conditions that optimize microbial recovery should be established to help evaluate the effectiveness of treatment conditions for food safety. the objectives of this study were to determine the effects of growth and recovery temperatures on pressure resistance of early stationary-phase listeria monocytogenes in milk. the tested conditions were the following: (1) l. monocytogenes was grown at various temper ...201019931930
molecular and genetic characterization of a novel bacteriocin locus in enterococcus avium isolates from infants.enterococci are among the most common human intestinal lactic acid bacteria, and they are known to produce bacteriocins. in this study, fecal enterococci were isolated from infants and screened for bacteriocin production. bacteriocin-producing enterococcus avium isolates were obtained, and a new pediocin-like bacteriocin was purified and characterized. this bacteriocin, termed avicin a, was found to be produced by isolates from two healthy infants. it was purified to homogeneity from culture sup ...201019933345
transcriptomic response of listeria monocytogenes to iron limitation and fur mutation.iron is required by almost all bacteria, but concentrations above physiological levels are toxic. in bacteria, intracellular iron is regulated mostly by the ferric uptake regulator, fur, or a similar functional protein. iron limitation results in the regulation of a number of genes, especially those involved in iron uptake. a subset of these genes is the fur regulon under the control of fur. in the present study, we have identified fur- and iron-regulated genes in listeria monocytogenes by dna m ...201019933349
monitoring bacterial indicators and pathogens in cattle feedlot waste by real-time pcr.quantitative microbial health risk assessment requires accurate enumeration of pathogens in hazard-containing matrices as part of the risk characterization process. as part of a risk management-oriented study of cattle feedlot waste contaminants, we investigated the utility of quantitative real-time pcr (qpcr) for surveying the microbial constituents of different faecal wastes. the abundance of escherichia coli and enterococci were first estimated in five cattle feedlot waste types from five loc ...201019939430
dcs in mouse models of intracellular bacterial infection.direct infection of antigen-presenting cells (apcs) with living intracellular bacteria may influence the early innate immune response as well as the following t-cell response. revealing the identity of primarily targeted cells during infection is therefore an important task, which requires sensitive methods for the intracellular detection of bacteria before their extensive replication. determination of colony-forming units (cfu) combines - in contrast to microscopy-based methods - a high sensiti ...201019941122
defining a role for hfq in gram-positive bacteria: evidence for hfq-dependent antisense regulation in listeria monocytogenes.small trans-encoded rnas (srnas) modulate the translation and decay of mrnas in bacteria. in gram-negative species, antisense regulation by trans-encoded srnas relies on the sm-like protein hfq. in contrast to this, hfq is dispensable for srna-mediated riboregulation in the gram-positive species studied thus far. here, we provide evidence for hfq-dependent translational repression in the gram-positive human pathogen listeria monocytogenes, which is known to encode at least 50 srnas. we show that ...201019942685
immobilization of bacteriophages on modified silica particles.bacteriophages are selective anti-bacterial agents, which are receiving increasing acceptance by regulatory agencies for use both in the food industry and in clinical settings for biocontrol. while immobilized phage could be particularly useful to create antimicrobial surfaces, current immobilization strategies require chemical bioconjugation to surfaces or more difficult processes involving modification of their head proteins to express specific binding moieties, for example, biotin or cellulos ...201019945158
the overgrowth of listeria monocytogenes by other listeria spp. in food samples undergoing enrichment cultivation has a nutritional basis.the isolation of listeria monocytogenes from food is carried out using a double enrichment. in cases where multiple listeria species are present within the original sample, l. monocytogenes can be overgrown during enrichment by other species of listeria present in the original sample. from a practical perspective, this can result in a false negative or complicate the ability of public health investigators to match food and clinical isolates. we have further investigated this phenomenon by analys ...201019945759
diverse cadmium resistance determinants in listeria monocytogenes isolates from the turkey processing plant environment.two different cada cadmium resistance determinants (cada1, first identified in tn5422, and cada2, associated with plm80) were detected among cadmium-resistant listeria monocytogenes strains from turkey processing plants. prevalence of cada1 versus cada2 was serotype associated. cadmium-resistant isolates that were also resistant to benzalkonium chloride (bc) were more likely to harbor cada2 alone or together with cada1 than isolates that were cadmium resistant but bc susceptible.201019948870
il-15 regulates both quantitative and qualitative features of the memory cd8 t cell pool.memory t cells are critical for immunity to various intracellular pathogens. recent studies have indicated that cd8 secondary memory cells, induced by prime-boost approaches, show enhanced protective function compared with primary memory cells and exhibit phenotypic and functional characteristics that distinguish them from primary memory cells. however, little is known about the cytokine requirements for generation and maintenance of boosted memory cd8 t cells. we studied the role of il-15 in de ...201019949092
antilisterial activity of a broad-spectrum bacteriocin, enterocin lr/6 from enterococcus faecium lr/6.enterocin lr/6, a purified bacteriocin, exhibited broad inhibitory spectrum both against related as well as some food-borne pathogens such as listeria monocytogenes, yersinia enterocolitica, aeromonas sp., shigella sp., and bacillus licheniformis. in this investigation, we have focused on l. monocytogenes as the target organism, as it is not only an important pathogen but can also survive over a wide range of environmental conditions such as refrigeration temperature, low ph, and high-salt conce ...201019957209
reduction of listeria monocytogenes on the surface of fresh channel catfish fillets by bacteriophage listex p100.bacteriophage listex p100 (phage p100) was approved by the u.s. food and drug administration and u.s. department of agriculture's food safety and inspection service for listeria monocytogenes control on both raw and ready-to-eat food products. in this article, we present the proof of concept on the influence of phage dose, phage contact time, and storage temperature on the listericidal activity of phage p100 in reducing the l. monocytogenes loads on the surface of fresh channel catfish fillet. t ...201019958102
evaluation of a multiplex pcr assay as an alternative method for listeria monocytogenes serotyping.listeria monocytogenes serotyping is commonly used as the first level of characterisation in the epidemiological surveillance of food and clinical isolates and is therefore widely accepted. the aim of this study was to define a scheme for multiplex molecular serotyping of l. monocytogenes based on a previously described pcr assay and then to evaluate and compare this new procedure with conventional serotyping by agglutination. the study included 1204 listeria strains collected from food products ...201019958798
different routes of bacterial infection induce long-lived th1 memory cells and short-lived th17 cells.we used a sensitive method based on tetramers of peptide and major histocompatibility complex ii (pmhcii) to determine whether cd4(+) memory t cells resemble the t helper type 1 (t(h)1) and interleukin 17 (il-17)-producing t helper (t(h)17) subsets described in vitro. intravenous or intranasal infection with listeria monocytogenes induced pmhcii-specific cd4(+) naive t cells to proliferate and produce effector cells, about 10% of which resembled t(h)1 or t(h)17 cells, respectively. t(h)1 cells w ...201019935657
short-term inhibition of p53 combined with keratinocyte growth factor improves thymic epithelial cell recovery and enhances t-cell reconstitution after murine bone marrow transplantation.myeloablative conditioning before bone marrow transplantation (bmt) results in thymic epithelial cell (tec) injury, t-cell immune deficiency, and susceptibility to opportunistic infections. conditioning regimen-induced tec damage directly contributes to slow thymopoietic recovery after bmt. keratinocyte growth factor (kgf) is a tec mitogen that stimulates proliferation and, when given before conditioning, reduces tec injury. some tec subsets are refractory to kgf and functional t-cell responses ...201019965631
cd4+ t cell regulation of cd25 expression controls development of short-lived effector cd8+ t cells in primary and secondary responses.both cd4(+) t cell help and il-2 have been postulated to "program" activated cd8(+) t cells for memory cell development. however, the linkage between these two signals has not been well elucidated. here we have studied effector and memory cd8(+) t cell differentiation following infection with three pathogens (listeria monocytogenes, vesicular stomatitis virus, and vaccinia virus) in the absence of both cd4(+) t cells and il-2 signaling. we found that expression of cd25 on antigen-specific cd8(+) ...201019966302
hydrophobization and antimicrobial activity of chitosan and paper-based packaging material.this study reports the elaboration of water-resistant, antimicrobial, chitosan and paper-based materials as environmentally friendly food packaging materials. two types of papers were coated with chitosan-palmitic acid emulsions or with a blend of chitosan and o,o'-dipalmitoylchitosan (dpct). micromorphology studies showed that inclusion of hydrophobic compounds into the chitosan matrix was enhanced by grafting them onto chitosan and that this led to their penetration of the paper's core. compar ...201019994882
multiple innate signaling pathways cooperate with cd40 to induce potent, cd70-dependent cellular immunity.we have previously shown that toll-like receptor (tlr) agonists cooperate with cd40 to generate cd8 t cell responses exponentially larger than the responses generated with traditional vaccine formulations. we have also shown that combined tlr agonist/anti-cd40 immunization uniquely induces the upregulation of cd70 on antigen bearing dendritic cells (dcs). in contrast, immunization with either a tlr agonist or a cd40 stimulus alone does not significantly increase cd70 expression on dcs. furthermo ...201019995538
combined effects of probiotic fermentation and high-pressure extraction on the antioxidant, antimicrobial, and antimutagenic activities of deodeok (codonopsis lanceolata).this study was designed to evaluate the combined effects of probiotic fermentation and high-pressure extraction (hpe) on the functional properties of codonopsis lanceolata. the ground c. lanceolata samples were anaerobically fermented with lactobacillus acidophilus adh, bifidobacterium longum b6, lactobacillus rhamnosus gg, or lactobacillus paracasei at 37 degrees c for 10 days and subjected to 500 mpa at 50 degrees c for 30 min. the extraction yields of c. lanceolata samples were noticeably inc ...201020000575
the combination of energy-dependent internal adaptation mechanisms and external factors enables listeria monocytogenes to express a strong starvation survival response during multiple-nutrient starvation.the goal of this study was to characterize the starvation survival response (ssr) of a wild-type listeria monocytogenes 10403s and an isogenic deltasigb mutant strain during multiple-nutrient starvation conditions over 28 days. this study examined the effects of inhibitors of protein synthesis, the proton motive force, substrate level phosphorylation, and oxidative phosphorylation on the ssr of l. monocytogenes 10403s and a deltasigb mutant during multiple-nutrient starvation. the effects of sta ...201020001327
listeriosis: a resurgent foodborne infection.listeria monocytogenes is the causative agent of human listeriosis, a potentially fatal foodborne infection. clinical manifestations range from febrile gastroenteritis to more severe invasive forms, including sepsis, meningitis, rhombencephalitis, perinatal infections, and abortions. in recent years, an increasing rate of listeriosis has been reported in several european countries. these increases primarily reflect a higher rate of bacteraemic listeriosis in those > or =65 years of age, and are ...201020002687
exaggerated inflammation, impaired host defense, and neuropathology in progranulin-deficient mice.progranulin (pgrn) is a widely expressed protein involved in diverse biological processes. haploinsufficiency of pgrn in the human causes tau-negative, ubiquitin-positive frontotemporal dementia (ftd). however, the mechanisms are unknown. to explore the role of pgrn in vivo, we generated pgrn-deficient mice. macrophages from these mice released less interleukin-10 and more inflammatory cytokines than wild type (wt) when exposed to bacterial lipopolysaccharide. pgrn-deficient mice failed to clear ...201020026663
naturally occurring altered peptide ligands control salmonella-specific cd4+ t cell proliferation, ifn-gamma production, and protective potency.t cell activation required for host defense against infection is an intricately regulated and precisely controlled process. although in vitro studies indicate that three distinct stimulatory signals are required for t cell activation, the precise contribution of each signal in regulating t cell proliferation and differentiation after in vivo infection is unknown. in this study, altered peptide ligands (apls) derived from the protective salmonella-specific flic ag and cd4+ t cells specific for th ...201020026741
constitutive activation of wnt signaling favors generation of memory cd8 t cells.t cell factor-1 (tcf-1) and lymphoid enhancer-binding factor 1, the effector transcription factors of the canonical wnt pathway, are known to be critical for normal thymocyte development. however, it is largely unknown if it has a role in regulating mature t cell activation and t cell-mediated immune responses. in this study, we demonstrate that, like il-7ralpha and cd62l, tcf-1 and lymphoid enhancer-binding factor 1 exhibit dynamic expression changes during t cell responses, being highly expres ...201020026746
gram-positive and gram-negative bacteria induce different patterns of cytokine production in human mononuclear cells irrespective of taxonomic relatedness.upon bacterial stimulation, tissue macrophages produce a variety of cytokines that orchestrate the immune response that clears the infection. we have shown that gram-positives induce higher levels of interleukin-12 (il-12), interferon-gamma (ifn-gamma), and tumor necrosis factor (tnf) from human peripheral blood mononuclear cells (pbmcs) than do gram-negatives, which instead induce more of il-6, il-8, and il-10. here, we study whether these patterns follows or crosses taxonomic borders. pbmcs fr ...201020028205
evidence for the involvement of acta in maturation of the listeria monocytogenes phagosome. 201020029388
inhibition of listeria monocytogenes infection by neurological drugs.to gain insights into the cellular processes required for intracellular bacterial pathogenesis, we previously developed a generalisable screening approach to identify small molecule compounds that alter listeria monocytogenes infection. in this report, a small molecule library enriched for compounds affecting neurological functions was screened and 68 compounds that disrupted l. monocytogenes infection of macrophages were identified. many of these compounds were known antimicrobial agents, howev ...201020031379
occurrence of listeria monocytogenes in salami manufactured in the marche region (central italy).the aim of the present study was to investigate the occurrence of listeria monocytogenes in salami samples collected from production plants of the marche region, and to assess the end-product acceptability based on the former italian regulations and european commission (ec) regulation no 2073/2005. based on the limits specified in the former italian regulations, the percentage of non-acceptable samples was 34.3%, whereas based on the limits specified in ec regulation n degrees 2073/2005, a lower ...201020035114
effects of rhynchophylline and isorhynchophylline on nitric oxide and endothelin-1 secretion from rimecs induced by listeriolysin o in vitro.to investigate the effects of listeriolysin o (llo) on morphology, nitric oxide (no) and endothelin-1 (et-1) release by rat intestinal microvascular endothelial cells (rimecs). we aimed to elucidate a preliminary therapeutic mechanism of action of rhynchophylline and isorhynchophylline (active components of uncaria rhynchophylla) on listeriosis treatment and how they regulate the llo-induced parasecretion of vasoactive agents in rimecs. a rimecs injury model was established by stimulating the ce ...201020036082
antimicrobial compounds produced by lactobacillus sakei subsp. sakei 2a, a bacteriocinogenic strain isolated from a brazilian meat product.bacteriocins produced by lactic acid bacteria are gaining increased importance due to their activity against undesirable microorganisms in foods. in this study, a concentrated acid extract of a culture of lactobacillus sakei subsp. sakei 2a, a bacteriocinogenic strain isolated from a brazilian pork product, was purified by cation exchange and reversed-phase chromatographic methods. the amino acid sequences of the active antimicrobial compounds determined by edman degradation were compared to kno ...201020037770
listeria monocytogenes-infected human peripheral blood mononuclear cells produce il-1beta, depending on listeriolysin o and nlrp3.different nod-like receptors, including nlrp1, nlrp3, and nlrc4, as well as the recently identified hin-200 protein, aim2, form multiprotein complexes called inflammasomes, which mediate caspase-1-dependent processing of pro-il-1beta. listeria monocytogenes is an intracellular pathogen that is actively phagocytosed by monocytes/macrophages and subsequently escapes from the phagosome into the host cell cytosol, depending on its pore-forming toxin listeriolysin o (llo). in this study, we demonstra ...201020008285
glimpsing the real cd4+ t cell response. 201020016511
cem-101, a novel fluoroketolide: antimicrobial activity against a diverse collection of gram-positive and gram-negative bacteria.cem-101 is a novel fluoroketolide with reported high potency against diverse groups of gram-positive (micrococcus spp., viridans group streptococci, corynebacterium spp. listeria monocytogenes, clostridium spp., etc.) and gram-negative bacteria (neisseria gonorrhoeae, campylobacter jejuni, helicobacter pylori, bacteroides fragilis, shigella spp., etc.), including mycoplasma and ureaplasma, as well as bacteria commonly associated with community-acquired respiratory tract infections and skin and s ...201020022192
effects of chitosan films on the growth of listeria monocytogenes, staphylococcus aureus and salmonella spp. in laboratory media and in fish soup.the objective of this study was to assess the antimicrobial effectiveness of chitosonium acetate films on the growth of listeria monocytogenes, salmonella spp. and staphylococcus aureus. the samples were tested in both laboratory conditions using tryptone soy broth (tsb) and in a real food system using fish soup. the study was carried out at different temperatures (4, 12, and 37 degrees c) in order to discern the influence of such variables. moreover, a sensory evaluation of the final product wa ...201020022649
the increasing prevalence of listeriosis--what are we missing? 201020042433
adiponectin is required for enhancement of ccl2 expression in adipose tissue during listeria monocytogenes infection.obesity is an important background of metabolic syndrome progression. our previous study demonstrated that chemokine ccl2 expression was suppressed in liver of obese mice that were highly susceptible to listeria monocytogenes infection. we investigated the role of adiponectin in ccl2 expression in obese mice after l. monocytogenes infection. when leptin-deficient obese ob/ob mice were infected intraperitoneally with l. monocytogenes, the elimination of bacteria from spleen, liver, mesenteric lym ...201020045352
modeling logistic performance in quantitative microbial risk assessment.in quantitative microbial risk assessment (qmra), food safety in the food chain is modeled and simulated. in general, prevalences, concentrations, and numbers of microorganisms in media are investigated in the different steps from farm to fork. the underlying rates and conditions (such as storage times, temperatures, gas conditions, and their distributions) are determined. however, the logistic chain with its queues (storages, shelves) and mechanisms for ordering products is usually not taken in ...201020055976
contemporary strategies in combating microbial contamination in food chain.the objective of this review has been to disclose collected information on benefits and risks of selected "less-than - sterilizing" processes applied to control microbial hazards in food that was meticulously collected and critically reviewed during five years of eu sixth framework project "pathogen combat". the target organisms of the project, and thus of this review, too, were listeria monocytogenes, escherichia coli o157:h7 and campylobacter jejuni. due to their specific response and high rel ...201020056287
effects of exposure to poultry chemical decontaminants on the membrane fluidity of listeria monocytogenes and salmonella enterica strains.there is a lack of work comparing the influence of various poultry chemical decontaminants on the membrane fluidity of pathogenic bacteria. in order to assess the possible role of physical membrane changes on bacterial adaptation to decontaminants, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (dph) was measured in listeria monocytogenes and salmonella enterica strains before and after growth in the presence of increasing sub-lethal concentrations of decontaminants (trisodium phosphat ...201020056288
the major pep-phosphotransferase systems (ptss) for glucose, mannose and cellobiose of listeria monocytogenes, and their significance for extra- and intracellular growth.in this report we examine the pep-dependent phosphotransferase systems (ptss) of listeria monocytogenes egd-e, especially those involved in glucose and cellobiose transport. this l. monocytogenes strain possesses in total 86 pts genes, encoding 29 complete ptss for the transport of carbohydrates and sugar alcohols, and several single pts components, possibly supporting transport of these compounds. by a systematic deletion analysis we identified the major ptss involved in glucose, mannose and ce ...201020056707
microbiological quality of raw milk used for small-scale artisan cheese production in vermont: effect of farm characteristics and practices.this study 1) evaluated the overall milk quality and prevalence of 4 target pathogens (listeria monocytogenes, staphylococcus aureus, salmonella spp., and escherichia coli o157:h7) in raw milk used for small-scale artisan cheesemaking and 2) examined specific farm characteristics and practices and their effect on bacterial and somatic cell counts (scc). raw milk samples were collected weekly from 21 artisan cheese operations (6 organic) in the state of vermont that manufactured raw-milk cheese f ...201020059912
disk abalone (haliotis discus discus) expresses a novel antistasin-like serine protease inhibitor: molecular cloning and immune response against bacterial infection.a novel antistasin-like cdna homologue named as ab-antistasin was isolated from the disk abalone haliotis discus discus normalized cdna library. the ab-antistasin (1398-bp) consisted of an 1185-bp open reading frame encoding 395 amino acid (aa) residues. the predicted molecular mass and isoelectric point of ab-antistasin was 44 kda and 8.5, respectively, and showed highest identity (23.1%) to hydra magnipapillata antistasin. the most striking feature of ab-antistasin is the 12-fold internal repe ...201020060477
overcoming the hurdles in using mouse genetic models that block tgf-beta signaling.the recent recognition of the importance of transforming growth factor beta (tgf-beta) in mediating many cellular immune functions has popularized the use of mouse models where tgf-beta signaling is blocked in specific cell types. however, there are some caveats affiliated with each model. here we describe and show evidence for some of the limitations of these models and provide insight into ways to improve the utility of these animals for in vivo studies.201020060833
genome organization and characterization of the virulent lactococcal phage 1358 and its similarities to listeria phages.virulent phage 1358 is the reference member of a rare group of phages infecting lactococcus lactis. electron microscopy revealed a typical icosahedral capsid connected to one of the smallest noncontractile tails found in a lactococcal phage of the siphoviridae family. microbiological characterization identified a burst size of 72 virions released per infected host cell and a latent period of 90 min. the host range of phage 1358 was limited to 3 out of the 60 lactococcal strains tested. moreover, ...201020061452
listeriolysin o is necessary and sufficient to induce autophagy during listeria monocytogenes infection.recent studies have suggested that autophagy is utilized by cells as a protective mechanism against listeria monocytogenes infection.201020062534
influence of fatty acid precursors, including food preservatives, on the growth and fatty acid composition of listeria monocytogenes at 37 and 10degreesc.listeria monocytogenes is a food-borne pathogen that grows at refrigeration temperatures and increases its content of anteiso-c(15:0) fatty acid, which is believed to be a homeoviscous adaptation to ensure membrane fluidity, at these temperatures. as a possible novel approach for control of the growth of the organism, the influences of various fatty acid precursors, including branched-chain amino acids and branched- and straight-chain carboxylic acids, some of which are also well-established foo ...201020048057
synergistic effects of sodium chloride, glucose, and temperature on biofilm formation by listeria monocytogenes serotype 1/2a and 4b strains.biofilm formation by listeria monocytogenes is generally associated with its persistence in the food-processing environment. serotype 1/2a strains make up more than 50% of the total isolates recovered from food and the environment, while serotype 4b strains are most often associated with major outbreaks of human listeriosis. using a microplate assay with crystal violet staining, we examined biofilm formation by 18 strains of each serotype in tryptic soy broth with varying concentrations of gluco ...201020048067
bacteriophage significantly reduces listeria monocytogenes on raw salmon fillet tissue.we have demonstrated the antilisterial activity of generally recognized as safe (gras) bacteriophage listex p100 (phage p100) on the surface of raw salmon fillet tissue against listeria monocytogenes serotypes 1/2a and 4b. in a broth model system, phage p100 completely inhibited l. monocytogenes growth at 4 degrees celsius for 12 days, at 10 degrees celsius for 8 days, and at 30 degrees celsius for 4 days, at all three phage concentrations of 10(4), 10(6), and 10(8) pfu/ml. on raw salmon fillet ...201020051201
production, characterization, and antimicrobial activity of a bacteriocin from newly isolated enterococcus faecium ij-31.this work aimed to isolate and characterize enterococcus spp. from indigenous dairy products in islamabad, pakistan. by classical microbiological techniques, one strain from a butter sample was identified to be enterococcus faecium, and we designated it e. faecium ij-31. the precise identity of this strain was then established by determining the sequence of its 16s and 23s rrna genes. the sequence homology searches revealed matches with a number of previously reported strains, such as e. faecium ...201020051203
comparison of invasiveness among surface-adherent variants of listeria monocytogenes in caco-2 cell culture assays.the persistence of listeria monocytogenes in meat processing plants is believed to be partly linked with their adherence properties to abiotic surfaces that may allow contamination of ready-to-eat (rte) foods. isolates of raw meats, rte meats and environmental samples from rte meat processing facilities that demonstrated differences in adherence to abiotic surfaces (glass, plastic, stainless steel, and rubber) were tested for cellular adherence and invasion in the caco-2 human cell line. strains ...201020051303
enhanced antimicrobial activity of starch-based film impregnated with thermally processed tannic acid, a strong antioxidant.starch-based films impregnated with fresh tannic acid (fta/starch film) and thermally processed tannic acid (pta/starch film) were assessed for inhibition of escherichia coli o157:h7 and listeria monocytogenes. disc-diffusion assay revealed that the pta/starch film showed larger clear zone around the film on the bacterial lawn than the fta/starch film at the same tannic acid concentrations (0.45 to 4.5mg per disc). viable cell count assays in tryptic soy broth showed that the pta/starch film als ...201020051308
listeria marthii sp. nov., isolated from the natural environment, finger lakes national forest.four isolates (fsl s4-120(t), fsl s4-696, fsl s4-710, and fsl s4-965) of gram-positive, motile, facultatively anaerobic, non-spore-forming bacilli that were phenotypically similar to species of the genus listeria were isolated from soil, standing water and flowing water samples obtained from the natural environment in the finger lakes national forest, new york, usa. the four isolates were closely related to one another and were determined to be the same species by whole genome dna-dna hybridizat ...201019667380
differences in listeria monocytogenes contamination of rural ohio residences with and without livestock.to determine the contribution of on-site livestock to the environmental contamination of rural households with listeria monocytogenes, a total of 1779 environmental and food samples were collected from 26 ruminant-farm households and 26 rural households in ohio. l. monocytogenes isolates were identified and differentiated using sequence comparisons of the intragenic regions of inlb and inlc. l. monocytogenes was isolated from shoes, 9.6% (20/208); utility gloves, 5.4% (6/111); kitchen sinks, 1.5 ...201019735200
sensitivity to acetic acid, ability to colonize abiotic surfaces and virulence potential of listeria monocytogenes egd-e after incubation on parsley leaves.to investigate how the survival of listeria monocytogenes on parsley leaves may affect its ability to sustain process-related harsh conditions and its virulence.201019778346
survival of clinical and food isolates of listeria monocytogenes through simulated gastrointestinal tract conditions.twenty-seven strains of listeria monocytogenes previously isolated from food (n = 16) and human patients of listeriosis (n = 11) were characterized and compared based on their ability to survive through the simulated gastrointestinal tract conditions. cells were exposed (60 or 120 min) to low ph in the presence of pepsin, to simulate the digestion in the stomach, and subsequently to bile salts to simulate the digestion in the small intestine (60 or 120 min). their survival was shown to be origin ...201019785538
serovar 4b complex predominates among listeria monocytogenes isolates from imported aquatic products in china.listeria monocytogenes, the causative organism of listeriosis, is primarily transmitted to humans through contaminated food. in this study, we examined 1275 batches of aquatic products imported from 29 countries and found that 36 batches from 8 countries were contaminated by listeria (2.8%), with l. monocytogenes accounting for 2.6% (33/1275) and l. innocua for 0.2% (3/1275). of the 23 selected l. monocytogenes isolates (from the 33 identified), 15 (65.2%) were of serovar 4b complex (4b, 4d, or ...201019735205
effects of metal compounds with distinct physicochemical properties on iron homeostasis and antibacterial activity in the lungs: chromium and vanadium.in situ reactions of metal ions or their compounds are important mechanisms by which particles alter lung immune responses. the authors hypothesized that major determinants of the immunomodulatory effect of any metal include its redox behavior/properties, oxidation state, and/or solubility, and that the toxicities arising from differences in physicochemical parameters are manifest, in part, via differential shifts in lung iron (fe) homeostasis. to test the hypotheses, immunomodulatory potentials ...201019757987
growth and reducing capacity of listeria monocytogenes under different initial redox potential.to determine the reducing capacity of listeria monocytogenes and to highlight the effect of redox potential on its growth parameters.201019645768
the risk of listeria monocytogenes infection in beef cattle operations.to determine the prevalence of listeria monocytogenes and associated risk factors among beef operations (cow-calf and feedlot) in central and southern california.201019664067
community-acquired acute bacterial meningitis in the elderly in turkey.this investigation aimed both to delineate the current status of community-acquired acute bacterial meningitis and to produce data on the interrelationships between clinical, laboratory and therapeutic parameters in the elderly. this retrospective cohort study was conducted in 28 turkish institutions in 159 culture-positive patients over the age of 50 years. streptococcus pneumoniae was the most common pathogen (69.2%), followed by listeria monocytogenes (8.8%). for this reason, antilisterial an ...201019732089
antimicrobial mortar surfaces for the improvement of hygienic conditions.to evaluate the effectiveness of various antimicrobial mortar formulations in inhibiting the growth of a selection of pathogens of environmental and hygienic concern.201019583799
efficacy of amoxicillin bearing microsphere formulation in treatment of listeria monocytogenes infection in swiss albino mice.the present study deals with the evaluation of the efficacy of amoxicillin bearing poly-lactic-glycolic acid (plga) microsphere formulation in treatment of experimental listeriosis in swiss albino mice. amoxicillin bearing plga microspheres were prepared by water-in-oil-in-water emulsion technique. plga microwspheres significantly regulated sustained release of encapsulated drug over extended time period. the rate of release increased in temperature dependent manner. amoxicillin bearing plga mic ...201019624287
occurrence of salmonella, campylobacter, yersinia enterocolitica, escherichia coli o157 and listeria monocytogenes in swine.the objective of this study was to investigate the occurrence of major bacterial foodborne pathogens in swine. in total, 359 samples from manure storage tanks (91) and fresh pooled faeces (268) obtained from finisher (110), sows (78) and weanlings (80) were collected and tested. campylobacter, salmonella, yersinia enterocolitica, escherichia coli o157 and listeria monocytogenes were isolated from 36.5%, 31.5%, 5.8%, 3.3% and 3.3% of samples respectively. all e. coli o157 isolates found on 10 far ...201019638163
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