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physiology and genetics of listeria monocytogenes survival and growth at cold temperatures.listeria monocytogenes is a foodborne pathogen that can cause serious invasive human illness in susceptible patients, notably immunocompromised, pregnant women, and adults > 65 years old. most human listeriosis cases appear to be caused by consumption of refrigerated ready-to-eat foods that are contaminated with high levels of l. monocytogenes. while initial l. monocytogenes levels in contaminated foods are usually low, the ability of l. monocytogenes to survive and multiply at low temperatures ...200919093268
fate of listeria monocytogenes in ready-to-eat turkey breast rolls formulated with antimicrobials following electron-beam irradiation.the objective of this study was to determine the effect of antimicrobials on the survival and proliferation of listeria monocytogenes in turkey breast rolls following electron-beam irradiation. six antimicrobial additive treatments that include no preservatives (control), 0.1% potassium benzoate (pb), 2% sodium lactate (sl), 0.1% potassium benzoate plus 2% sodium lactate (pb + sl), 2% sodium lactate plus 0.1% sodium diacetate (sl + sda), and 0.1% potassium benzoate, 2% sodium lactate, and 0.1% s ...200919096075
foodborne pathogens and microbiological characteristics of raw milk soft cheese produced and on retail sale in brazil.the consumption of raw milk soft cheeses (rmsc), which are typically manufactured in small dairy farms under unsatisfactory hygiene conditions, is common in brazil. due to these production characteristics, this type of cheese is a potential carrier of pathogenic microorganisms, such as listeria monocytogenes, salmonella, and enterotoxin-producing staphylococcus spp. considering these characteristics, in this work, we aimed to detect the presence of these pathogenic microorganisms in rmc and to e ...200919099356
antibacterial effects of roselle calyx extracts and protocatechuic acid in ground beef and apple juice.the antibacterial effects of roselle calyx aqueous and ethanol extracts and protocatechuic acid against food spoilage bacteria salmonella typhimurium dt104, escherichia coli o157:h7, listeria monocytogenes, staphylococcus aureus, and bacillus cereus were examined. minimal inhibitory concentrations of roselle calyx aqueous and ethanol extracts and protocatechuic acid against these bacteria were in the range of 112-144, 72-96, and 24-44 microg/ml, respectively. protocatechuic acid content in rosel ...200919099360
listeria monocytogenes in rte foods marketed in italy: prevalence and automated ecori ribotyping of the isolates.the aims of the present study were: (a) to investigate the prevalence and the enumeration of listeria monocytogenes in 200 samples of ready to eat (rte) foods of animal and vegetal origin collected from different outlets and processing plants in sardinia; (b) to characterize the isolates by phenotypical and molecular methods; (c) to analyze a subset of 42 l. monocytogenes by automated ecori ribotyping in order to predict the strain's potential virulence for humans. the strains were isolated from ...200919100643
single-chain variable fragment antibodies selected by phage display against the sporozoite surface antigen p23 of cryptosporidium parvum.cryptosporidium parvum, an apicomplexan parasite transmitted via animal fecal wastes, is the causative agent of cryptosporidiosis. clones were selected from 2 synthetic naïve human single-chain variable fragment (scfv) phagemid libraries that bound to the recombinant p23 protein of c. parvum. panning the tomlinson i and j phagemid libraries resulted in 6 distinct clones. two clones had full-length scfv sequences, while the remaining clones were either truncated or missing a section of the heavy ...200918576885
neonatal listeriosis in taiwan, 1990-2007.listeria monocytogenes is an important pathogen in neonates in western countries, with a fatality rate of 20-30%. there is limited information on neonatal listeriosis in eastern countries. the purpose of this study was to delineate the occurrence and clinical picture of neonatal listeriosis in taiwan.200918768340
ers a crp/fnr-like transcriptional regulator of enterococcus faecalis.ers has been identified in a recent study as a protein involved in the pathogenesis and the stress response of the lactic acid bacterium enterococcus faecalis, an opportunistic pathogen. in the e. faecalis sequenced genome, ers is annotated as a transcriptional regulator member of the crp/fnr family. this protein has been shown to be involved in the oxidative stress response as well as in the survival within macrophages. in the present study, we sum up the characteristics of ers and provide furt ...200918672305
a case of listeria meningoencephalitis complicated by hydrocephalus in an immunocompetent infant.we report a very unusual case of meningoencephalitis due to listeria monocytogenes in a 7-month-old immunocompetent boy. cerebrospinal fluid (csf) culture was initially negative, but was positive on the seventh day. the disease was complicated by seizures and hydrocephalus managed with temporary ventriculostomy. the infant was discharged without obvious neurological sequelae after 30 days and developed without neurological or developmental sequelae at two years of age. listeria is difficult to i ...200918463893
listeria monocytogenes meningitis associated with rhabdomyolysis and acute renal failure.numerous systemic infections are capable of inducing myositis and rhabdomyolysis. clinical course of the disease is in the great majority of patients benign and without development of renal dysfunction. however, serious consequences are possible if acute renal failure (arf) occurs, especially in critically ill patients.200918528786
survival of selected pathogens in diluted sludge of a thermophilic waste treatment plant and in nacl-solution under aerobic and anaerobic conditions.decimal reduction times (drt or d-value) of campylobacter jejuni, salmonella enterica (formerly salmonella choleraesuis) serovar senftenberg, escherichia coli, and listeria monocytogenes were determined in two different matrices, diluted fermenter sludge (dfs) and 0.95% nacl-solution (nacl) at 50 degrees c, both under aerobic and anaerobic conditions. depending on aeration, matrix composition, and the respective organism, the d-values varied between 10min and more than 15h. generally the viabili ...200918445518
horizontal gene transfer of virulence determinants in selected bacterial foodborne pathogens.this review describes horizontal gene transfer from a historical point of view, with descriptions of the first instances of the different bacterial transfer mechanisms: conjugation, transduction and transformation, as well as examples of some of the early acknowledged transfer events. gene transfer from four selected foodborne pathogens: escherichia coli, listeria monocytogenes,staphylococcus aureus and salmonella are highlighted.200918420327
the role of horizontal gene transfer in the evolution of selected foodborne bacterial pathogens.bacteria use various ways to transfer genetic information. these methods include: conjugation, which requires cell to cell contact between cells, transduction, which is bacteriophage-facilitated transfer of genetic information, and transformation, which is the uptake of free dna from the environment. usually the genes to be transferred lie on mobile genetic elements, pieces of dna that encode proteins important to facilitate movement of dna within or between genomes. this review highlights the t ...200918420329
an analysis of the factors for microbial contamination risk for pork at slaughterhouses in korea using the logit model.to assess the effect of slaughtering practices on the probability of microbial contamination at slaughterhouses in korea, 840 samples from 8 slaughterhouses were collected and 50 factors observed for 2 yr. target microorganisms were salmonella spp. and listeria monocytogenes and 20 contaminated samples were found. twenty-one out of 50 factors were identified as possible sources of microbial contamination. to narrow down the more critical factors and quantify the effects, simple regression analys ...200920077220
cutaneous listeria infection.this case introduces an unusual cutaneous manifestation of a potentially life-threatening infection. the circumstances of the inoculation are key to explaining both the cutaneous signs and how an individual who does not belong to what would be considered a conventional 'at risk' group developed systemic infection. however, cutaneous infection with listeria monocytogenes could be considered an occupational hazard for those working with livestock.200920081597
characterization of bacteriocin produced by streptococcus bovis j2 40-2 isolated from traditional fermented milk 'dahi'.a bacteriocin-producing strain streptococcus bovis j2 40-2 was isolated from traditional fermented milk 'dahi' in bangladesh. despite its narrow antimicrobial spectrum, it showed strong antimicrobial activity against extremely challenging and problematic organisms in foods, such as listeria monocytogenes. bacteriocin was sensitive to several proteolytic enzymes and showed antimicrobial activity over a wide ph range of 2.0-10.0. it was stable when heated to 110 degrees c for 20 min, but lost 25% ...200920163471
the impact of environmental stress on listeria monocytogenes virulence.listeria monocytogenes, a significant food-borne pathogen, must defy a variety of conditions encountered in the food environment and during the infection process. in reaction to adverse conditions, the bacteria significantly change their metabolism, inducing a stress response which is mediated by a range of alternative sigma factors. the extent of the response to stress was shown to vary in the l. monocytogenes population. according to recent evidence a major l. monocytogenes alternative sigma f ...200920169937
phenolics and anthocyanins in berries of european cranberry and their antimicrobial activity.european cranberry is a berry plant rich in biologically active substances, making it valued by both the phyto-pharmaceutical and food industries. the aim of this study was to examine the accumulation of phenolic compounds and anthocyanins in berries of european cranberry and to assess their antibacterial activity. material and methods: different wild clones of european cranberry were investigated according to berry weight and the amounts of total phenolics and anthocyanins. anthocyanin profiles ...200920173403
[listeria monocytogenes infection in a total knee arthroplasty].acute blood borne prosthetic infections occur in patients with an asymptomatic prosthesis that, after an infection involving bacteremia, produces bacterial implantation in the prosthesis and causes an acute infection. this type of infection is usually caused by gram positive cocci, streptococci and staphylococci. we present the clinical case of a patient without a history of immunodeficiency, who had an acute blood borne knee prosthetic infection caused by listeria monocytogenes.200920336882
dnase i inhibits a late phase of reactive oxygen species production in neutrophils.neutrophils kill bacteria on extracellular complexes of dna fibers and bactericidal proteins known as neutrophil extracellular traps (nets). the net composition and the bactericidal mechanisms they use are not fully understood. here, we show that treatment with deoxyribonuclease (dnase i) impairs a late oxidative response elicited by gram-positive and gram-negative bacteria and also by phorbol ester. isoluminol-dependent chemiluminescence elicited by opsonized listeria monocytogenes-stimulated n ...200920375609
food standards commission targets dangerous bacteria, chemicals. 200920377055
listeria monocytogenes internalin and e-cadherin: from bench to bedside.listeria monocytogenes is a gram-positive bacterium responsible for a severe infection associated with different clinical features (gastroenteritis, meningoencephalitis, and abortion in pregnant women). these pathologies are caused by the unusual capacity of the bacterium to cross three host barriers during infection and to invade nonphagocytic cells. to invade host cells, listeria uses two proteins, inla and inlb, which have specific receptors on the host-cell surface, e-cadherin and met, respe ...200920066101
myd88 and interferon-alpha/beta are differentially required for dendritic cell maturation but dispensable for development of protective memory against listeria.signalling pathways mediated by myd88 are important for sensing toll-like receptor (tlr) ligands and directing an immune response. however, the influence of myd88-derived cytokines and interferon (ifn)-alpha/beta, the latter being made by both myd88-dependent and -independent pathways, in phenotypic and functional dendritic cell (dc) maturation during infection is poorly understood. here we investigate the contribution of myd88-dependent and -independent pathways to dc maturation, cd8 t-cell act ...200920067542
[contribution of sigma b to environmental stress tolerance in listeria monocytogenes--a review].the alternative sigma factor sigma b plays important roles in both virulence and stress tolerance in listeria monocytogenes. it is now clear that there is a strong link between the virulence potential of listeria monocytogenes and its ability to tolerate stress. several studies have identified genes that play important roles in stress tolerance and virulence. for example, genes involved in osmotic stress tolerance, acid and alkaline tolerance, oxidative stress tolerance, extreme temperature tole ...200920069872
[a multi-pathogen selective enrichment broth for simultaneous growth of salmonella enteritidis, staphylococcus aureus, and listeria monocytogenes].a selective enrichment broth (ssl) was formulated to allow simultaneous growth of salmonella enteritidis, staphylococcus aureus, and listeria monocytogens.200920069888
[study on rapid detection techniques of pcr-elisa for listeria monocytogenes].to develop rapid pcr-elisa methods for detecting listeria monocytogenes, and detect food samples artificially contaminated with listeria monocytogenes.200920047217
antibacterial and antioxidant activities of the essential oil of artemisia echegarayi hieron. (asteraceae).artemisia echegarayi hieron. (asteraceae) is commonly known in argentina as "ajenjo". many studies report high efficacy of essential oils against food-borne pathogenic bacteria. the antimicrobial activity and minimal inhibitory concentration of a. echegarayi essential oil were evaluated against seven bacterial species of significant importance in food hygiene, by using the disc diffusion assay and the micro-well dilution method, respectively. volatile components of the extract were analyzed by g ...200920085186
tio2 nanowire bundle microelectrode based impedance immunosensor for rapid and sensitive detection of listeria monocytogenes. 200919995090
systemic listeriosis with adalimumab therapy. 200920009978
in this issue.hsst! histones rock!: pp. 5437-5445histones were a nuisance to molecular biologists in the early days - they were small, very basic, and did not do anything except neutralizing the charge on dna. then nucleosomes were discovered. containing two sets of histones and a discrete chunk of dna, they gave us structure. and now they give us targets. transcriptional accessibility to dna is regulated, in part, through the addition or removal of acetyl groups on histones. the work reported here by naldi e ...200920017151
deep rna sequencing of l. monocytogenes reveals overlapping and extensive stationary phase and sigma b-dependent transcriptomes, including multiple highly transcribed noncoding rnas.identification of specific genes and gene expression patterns important for bacterial survival, transmission and pathogenesis is critically needed to enable development of more effective pathogen control strategies. the stationary phase stress response transcriptome, including many sigmab-dependent genes, was defined for the human bacterial pathogen listeria monocytogenes using rna sequencing (rna-seq) with the illumina genome analyzer. specifically, bacterial transcriptomes were compared betwee ...200920042087
the bacterial pathogen listeria monocytogenes: an emerging model in prokaryotic transcriptomics.a major challenge in bacterial pathogenesis is understanding the molecular basis of the switch from saprophytism to virulence. following a recent whole-genome transcriptomic analysis using tiling arrays, an article published in bmc genomics reports the first use of rna-seq in listeria monocytogenes in order to identify genes controlled by sigma b, a transcriptional regulator with a critical role in virulence.200920053304
co-infection of market-age turkeys with escherichia coli and listeria monocytogenes in two stress models.we have hypothesized that stress-induced subclinical infection of turkeys with listeria monocytogenes may be an overlooked source of processing plant contamination, and we have shown that concurrent escherichia coli challenge can increase l. monocytogenes colonization. the objective of this study was to determine the effects of dexamethasone (dex) immunosuppressive treatment and transport stress on the isolation of l. monocytogenes in an e. coli-l. monocytogenes challenge model. thirteen-week-ol ...200920095148
[risk assessment of listeria monocytogenes in deli meats and vegetable salads].to analysis risk from listeria monocytogenes in deli meats and vegetable salads.200920137560
sting regulates intracellular dna-mediated, type i interferon-dependent innate immunity.the innate immune system is critical for the early detection of invading pathogens and for initiating cellular host defence countermeasures, which include the production of type i interferon (ifn). however, little is known about how the innate immune system is galvanized to respond to dna-based microbes. here we show that sting (stimulator of interferon genes) is critical for the induction of ifn by non-cpg intracellular dna species produced by various dna pathogens after infection. murine embry ...200919776740
prevalence and level of listeria monocytogenes and other listeria species in selected retail ready-to-eat foods in the united kingdom.although listeriosis is a rare cause of human disease in the united kingdom, an increase in the number of cases has been observed since 2001, almost exclusively in persons older than 60 years. this increase prompted this study on the microbiological safety of ready-to-eat (rte) foods, which included those types potentially linked to cases of listeriosis. between may 2006 and april 2007, 6,984 rte foods were sampled (2,168 sliced meats, 1,242 hard cheese, 1,088 sandwiches, 878 butter, 725 spreada ...200919777888
safety-based shelf life model for frankfurters based on time to detect listeria monocytogenes with initial inoculum below detection limit.the growth of listeria monocytogenes inoculated on frankfurters at four inoculum levels (0.1, 0.04, 0.01, and 0.007 cfu/g) was examined at 4, 8, and 12 degrees c until the time l. monocytogenes populations reached a detectable limit of at least 2 cfu/g. a scaled-down assumption was made to simulate a 25-g sample from a 100-lb batch size in a factory setting by using a 0.55-g sample from a 1,000-g batch size in a laboratory. samples of 0.55 g were enriched in pdx-lib selective medium, and presump ...200919777889
effects of mussel processing soils on the adherence of listeria monocytogenes to polypropylene and stainless steel.a comparative study of adhesion kinetics of l. monocytogenes (strains cect 5873, cect 936, cect 911, and cect 4032, representing serotypes 1/2a, 1/2b, 1/2c, and 4b, respectively) to polypropylene (pp) and stainless steel (ss) under two surface contamination conditions in plants processing cooked mussel was carried out. the conditions were either (i) contamination of clean surfaces with mussel cooking juice carrying l. monocytogenes or (ii) contamination with l. monocytogenes after soiling with m ...200919777890
properties of whey protein-based films containing organic acids and nisin to control listeria monocytogenes.whey protein isolate and glycerol were mixed to form a matrix to incorporate antimicrobial agents and produce edible films with antimicrobial activity against listeria monocytogenes strains isolated from cheeses. various organic acids were used to decrease ph down to approximately 3. in a preliminary assay without nisin, the effect of each organic acid was evaluated with respect to the rheological properties of the film solutions and the inhibitory and mechanical properties of the films. lactic, ...200919777891
disinfection of iceberg lettuce by titanium dioxide-uv photocatalytic reaction.securing the physical quality and microbial safety of fresh foods has been a major focus in the food industry. to improve quality and increase the shelf life of fresh produce, disinfection methods have been developed. titanium dioxide (tio2) photocatalytic reactions under uv radiation produce hydroxyl radicals that can be used for disinfection of foodborne pathogenic bacteria. we investigated the effects of tio2-uv photocatalytic disinfection on the shelf life of iceberg lettuce. counts of natur ...200919777894
comparison between the vitek immunodiagnostic assay system and pcr for the detection of pathogenic microorganisms in an experimental dry sausage during its curing process.the comparison between the vitek immunodiagnostic assay system (vidas) and pcr methods for the detection of the pathogenic microorganisms salmonella typhimurium, listeria monocytogenes, escherichia coli o157:h7, clostridium perfringens, and staphylococcus aureus in salchich6n (a type of spanish fermented dry sausage) was studied. the automated mini-vidas method and the pcr method were used to detect the presence of these microorganisms in 90 samples grouped into six batches (one control batch, a ...200919777902
neonatal immunization with listeria monocytogenes induces t cells with an adult-like avidity, sensitivity, and tcr-vbeta repertoire, and does not adversely impact the response to boosting.listeria monocytogenes (lm) holds promise as a neonatal vaccine vehicle. here we show that lm immunized neonatal mice reached maximal ag-specific cd8(+) t cell expansion after only a single immunization, while adults required two doses. ag-specific cd4(+) t cell expansion in both age groups required a boost to reach its peak. neither functional avidity, sensitivity, nor the tcr-vbeta repertoire of the ag-specific t cells differed between mice immunized as neonates or adults. lastly, neonatal imm ...200919796722
superior protective immunity against murine listeriosis by combined vaccination with cpg dna and recombinant salmonella enterica serovar typhimurium.preexisting antivector immunity can severely compromise the ability of salmonella enterica serovar typhimurium live vaccines to induce protective cd8 t-cell frequencies after type iii secretion system-mediated heterologous protein translocation in orally immunized mice. to circumvent this problem, we injected cpg dna admixed to the immunodominant p60(217-225) peptide from listeria monocytogenes subcutaneously into balb/c mice and coadministered a p60-translocating salmonella strain by the orogas ...200919797070
inactivation of listeria monocytogenes on unpackaged and vacuum-packaged chicken frankfurters using pulsed uv-light.the effectiveness of pulsed uv-light on the microbial load and quality of unpackaged and vacuum-packaged chicken frankfurters was investigated. samples were inoculated with listeria monocytogenes scott a on the top surfaces, and then treated with pulsed uv-light for 5, 15, 30, 45, and 60 s at 5, 8, and 13 cm distance from the quartz window in a pulsed uv-light chamber. log reductions (cfu/cm(2)) on unpackaged samples were between 0.3 and 1.9 after 5-s treatment at 13 cm and 60-s treatment at 5 c ...200919799670
edible apple film wraps containing plant antimicrobials inactivate foodborne pathogens on meat and poultry products.apple-based edible films containing plant antimicrobials were evaluated for their activity against pathogenic bacteria on meat and poultry products. salmonella enterica or e. coli o157:h7 (10(7) cfu/g) cultures were surface inoculated on chicken breasts and listeria monocytogenes (10(6) cfu/g) on ham. the inoculated products were then wrapped with edible films containing 3 concentrations (0.5%, 1.5%, and 3%) of cinnamaldehyde or carvacrol. following incubation at either 23 or 4 degrees c for 72 ...200919799671
universal primer-multiplex pcr approach for simultaneous detection of escherichia coli, listeria monocytogenes, and salmonella spp. in food samples.escherichia coli, listeria monocytogenes, and salmonella spp. are 3 kinds of the most important food-borne human pathogens. traditional microbiological analysis is labor-intensive, time-consuming, and easily contaminated, thus producing false positive signals; it also involves much subjectivity judgments. multiplex-pcr could be applied to detect multiple target organisms simultaneously to save time and labor, but there is always disproportionate amplification resulting from the disparity of diff ...200919799672
microwave oven heating for inactivation of listeria monocytogenes on frankfurters before consumption.microwave oven heating was evaluated for inactivation of listeria monocytogenes on inoculated and stored frankfurters. frankfurters formulated without/with 1.5% potassium lactate and 0.1% sodium diacetate were inoculated with l. monocytogenes (1.9 +/- 0.2 log cfu/cm(2)), vacuum-packaged, and stored (4 degrees c) to simulate conditions prior to purchase by consumers. at storage days 18, 36, and 54, packages were opened and placed at 7 degrees c, simulating aerobic storage in a household refrigera ...200919799673
synergistic antibacterial and anti-inflammatory activity of temporin a and modified temporin b in vivo.temporins are antimicrobial peptides secreted by the granular glands of the european red frog (rana temporaria). they are 10-14 amino acid long polypeptides active prevalently against gram positive bacteria. this study shows that a synthetic temporin b analogue (tb-yk), acquires the capacity to act in synergism with temporin a and to exert antimicrobial and anti-inflammatory activity in vivo against gram positive and gram negative bacteria. administration of 3.4 mg/kg of temporin a (ta)+1.6 mg/k ...200919784377
therapeutic cancer vaccines in cervical cancer: phase i study of lovaxin-c.producing effective therapeutic vaccines has proved much more difficult and challenging than developing cancer preventive vaccines. despite huge research in the area of cancer immunology, fda/emea have not approved any type of cancer treatment vaccine so far. more than 99% of cervical cancers have detectable amounts of human papillomavirus (hpv) dna. integration of high-risk hpv into the host cell genome is followed by continual expression of hpv e6 and e7 oncoproteins, making them excellent tar ...200919785060
fan stimulates tnf(alpha)-induced gene expression, leukocyte recruitment, and humoral response.factor associated with neutral sphingomyelinase activation (fan) is an adaptor protein that constitutively binds to tnf-r1. microarray analysis was performed in fibroblasts derived from wild-type or fan knockout mouse embryos to evaluate the role of fan in tnf-induced gene expression. approximately 70% of tnf-induced genes exhibited lower expression levels in fan-deficient than in wild-type fibroblasts. of particular interest, tnf-induced expression of cytokines/chemokines, such as il-6 and cxcl ...200919786552
sodium chloride affects listeria monocytogenes adhesion to polystyrene and stainless steel by regulating flagella expression.to study the adhesion capability of seven strains of listeria monocytogenes to polystyrene and stainless steel surfaces after cultivation at various nacl concentrations.200919793195
cutting edge: importance of il-6 and cooperation between innate and adaptive immune receptors in cellular vaccination with b lymphocytes.b lymphocytes are a potential alternative to dendritic cell immunotherapy, with the advantages of relative abundance in peripheral blood and the ability to function as apcs. although b cells express multiple receptors that induce costimulatory molecules, b cell vaccine studies have focused primarily on cd40 stimulation. to optimize the potential efficacy of b cell vaccines (bvac), we compared the capacity of differentially stimulated b cells to induce ag-specific cd8(+) t cell responses in vivo. ...200919801508
autophagy in immunity against intracellular bacteria.autophagy is an innate immune defense mechanism against various intracellular bacterial pathogens, such as salmonella enterica serovar typhimurium (s. typhimurium), listeria monocytogenes and shigella flexneri. s. typhimurium uses type three secretion systems (t3sss) to invade mammalian cells and replicate in salmonella-containing vacuoles (scvs). a small population of intracellular s. typhimurium is targeted by autophagy shortly after infection. evidence suggests that these bacteria are present ...200919802566
dendritic cell cross-priming is essential for immune responses to listeria monocytogenes.cross-presentation is now recognized as a major mechanism for initiating cd8 t cell responses to virus and tumor antigens in vivo. it provides an elegant mechanism that allows relatively few dendritic cells (dcs) to initiate primary immune responses while avoiding the consumptive nature of pathogenic infection. cd8 t cells play a major role in anti-bacterial immune responses; however, the contribution of cross-presentation for priming cd8 t cell responses to bacteria, in vivo, is not well establ ...200919806187
inactivation of the wall-associated de-n-acetylase (pgda) of listeria monocytogenes results in greater susceptibility of the cells to induced autolysis.several species of gram-positive bacteria have cell wall peptidoglycan (syn. murein) in which not all of the sugar moieties are n-acetylated. this has recently been shown to be a secondary effect, caused by the action of a peptidoglycan n-acetylglucosamine deacetylase. we have found that the opportunistic pathogen listeria monocytogenes is unusual in having three enzymes with such activity, two of which remain in the cytoplasm. here, we examine the enzyme (pgda) that crosses the cytoplasmic memb ...200919809250
pcr experion automated electrophoresis system to detect listeria monocytogenes in foods.listeria monocytogenes is frequently found as a contaminant in raw and ready-to-eat foods. the ability of l. monocytogenes to multiply at refrigeration temperatures and to grow in a wide range of ph values is of particular concern for food safety. according to the european union regulation on microbiological criteria for foodstuffs, l. monocytogenes must be absent in some categories of ready-to-eat foods. the standard microbiological method for l. monocytogenes detection in foods (iso 11290-1: 1 ...200919810054
transcriptional and post-transcriptional regulation of the gmar antirepressor governs temperature-dependent control of flagellar motility in listeria monocytogenes.flagellar motility in listeria monocytogenes (lm) is restricted to temperatures below 37 degrees c due to the opposing activities of the mogr transcriptional repressor and the gmar antirepressor. previous studies have suggested that both the degu response regulator and mogr regulate expression of gmar. in this report, we further define the role of degu for gmar production and flagellar motility. we demonstrate that deletion of the receiver domain of degu has no effect on flagellar motility in lm ...200919796338
listeria as an enteroinvasive gastrointestinal pathogen.the bacterium listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. listeria spp. are isolated from a diversity of environmental sources, including soil, water, effluents, a large variety of foods, and the feces of humans and animals. recent outbreaks demonstrated that l. monocytogenes can cause gastroenteritis in otherwise healthy individuals and more severe invasive disease in immunocompromised patients. common symptoms include fever, w ...200919812983
listeria monocytogenes ctap is a multifunctional cysteine transport-associated protein required for bacterial pathogenesis.the bacterial pathogen listeria monocytogenes survives under a myriad of conditions in the outside environment and within the human host where infections can result in severe disease. bacterial life within the host requires the expression of genes with roles in nutrient acquisition as well as the biosynthesis of bacterial products required to support intracellular growth. a gene product identified as the substrate-binding component of a novel oligopeptide transport system (encoded by lmo0135) wa ...200919818015
effects of bilimbi (averrhoa bilimbi l.) and tamarind (tamarindus indica l.) juice on listeria monocytogenes scott a and salmonella typhimurium atcc 14028 and the sensory properties of raw shrimps.the potential of using juice of bilimbi (averrhoa bilimbi l.) and tamarind (tamarindus indica l.) to reduce listeria monocytogenes scott a and salmonella typhimurium atcc 14028 populations on raw shrimps after washing and during storage (4 degrees c) was investigated. the uninoculated raw shrimps and those inoculated with approximately 9 log cfu/ml of l. monocytogenes scott a and s. typhimurium atcc 14028 were washed (dipped or rubbed) in distilled water (sdw) (control), bilimbi or tamarind juic ...200919818521
mast cell-mediated antigen presentation regulates cd8+ t cell effector functions.the characteristics, importance, and molecular requirements for interactions between mast cells (mcs) and cd8(+) t cells have not been elucidated. here, we demonstrated that mcs induced antigen-specific cd8(+) t cell activation and proliferation. this process required direct cell contact and mhc class i-dependent antigen cross-presentation by mcs and induced the secretion of interleukin-2, interferon-gamma, and macrophage inflammatory protein-1alpha by cd8(+) t cells. mcs regulated antigen-speci ...200919818652
analyzing the power and error of listeria monocytogenes growth challenge studies.domestic and international food safety policy developments have spurred interest in the design and interpretation of experimental growth challenge studies to determine whether ready-to-eat (rte) foods are able to support growth of listeria monocytogenes. existing challenge study protocols and those under development differ markedly in terms of experimental design and the acceptance criteria under which a rte food is determined not to support l. monocytogenes growth. consequently, the protocols d ...200919822374
isolation and 2-d-dige proteomic analysis of intracellular and extracellular forms of listeria monocytogenes.the pathogenicity of listeria monocytogenes is related to its ability of invading and multiplying in eukaryotic cells. its main virulence factors are now well characterized, but limited proteomic data is available concerning its adaptation to the intracellular environment. in this study, l. monocytogenes egd (serotype 1/2a) grown in human thp-1 monocytes (24 h) were successfully separated from host organelles and cytosolic proteins by differential and isopycnic centrifugation. for control, we us ...200919834917
[characterization of a naturally atypical listeria monocytogenes strain lacking inlab].we attempted to gain insights into the phenotypic and genetic characteristics of a naturally atypical listeria monocytogenes strain s10 lacking inlab.200919835164
differential effects of cytokines and corticosteroids on toll-like receptor 2 expression and activity in human airway epithelia.the recognition of microbial molecular patterns via toll-like receptors (tlrs) is critical for mucosal defenses.200919835594
comparison of different application strategies of divergicin m35 for inactivation of listeria monocytogenes in cold-smoked wild salmon.cold-smoked salmon treated with divergicin m35-producing carnobacterium divergens m35, c. divergens atcc 35677 (a non-producer of bacteriocin), purified divergicin m35 or supernatants of c. divergens m35 culture in snow crab hepatopancreas (sch) medium or mrs broth was challenged with listeria monocytogenes (up to 10(3) cfu/g). samples were stored at 4 degrees c for up to four weeks. l. monocytogenes, total bacterial and lactic acid bacterial counts were determined along with changes in total vo ...200919835762
inhibition by lactobacillus sakei of other species in the flora of vacuum packaged raw meats during prolonged storage.the abilities of five lactobacillus sakei strains and one lactococcus lactis strain to retain inhibitory activity against several target organisms in the flora of product during 12 weeks storage of vacuum-packaged lamb and beef was investigated. l. sakei strains were generally found capable of developing dominant populations on both beef and lamb. l. lactis 75 grew poorly on lamb did not inhibit co-inoculated brochothrix thermosphacta. lamb inoculated with the sakacin-a producer l. sakei lb706 h ...200919835775
resistance of listeria monocytogenes, escherichia coli o157:h7 and campylobacter jejuni after exposure to repetitive cycles of mild bactericidal treatments.while maintaining nutritional and sensorial attributes of fresh foods mild processing technologies generally deliver microbiologically perishable food products. currently little information exists on possible increase in the resistance of pathogens after repetitive exposure to mild (sub-lethal) treatments. multiple strain-cocktails of listeria monocytogenes, escherichia coli o157:h7 and campylobacter jejuni were exposed to 20 consecutive cycles of sub-lethal inactivation by three different techn ...200919835777
comparative analysis of acid resistance in listeria monocytogenes and salmonella enterica strains before and after exposure to poultry decontaminants. role of the glutamate decarboxylase (gad) system.data on the ability of chemical poultry decontaminants to induce an acid stress response in pathogenic bacteria are lacking. this study was undertaken in order to compare the survival rates in acid broths of listeria monocytogenes and salmonella enterica strains, both exposed to and not exposed to decontaminants. the contribution of the glutamate decarboxylase (gad) acid resistance system to the survival of bacteria in acid media was also examined. four strains (l. monocytogenes serovar 1/2, l. ...200919835779
occurrence of foodborne pathogens in irish farmhouse cheese.food safety is a critical factor in the production of farmhouse cheese. in ireland the varieties of farmhouse cheese produced reflect a much broader range than those produced commercially and some of these cheese varieties are associated with greater microbiological risk. these include cheese produced from unpasteurised milk and soft ripened cheese such as mould or smear-ripened cheeses which have high ph and relatively short ripening times. the aim of this study was to determine the microbiolog ...200919835780
insertional mutagenesis of listeria monocytogenes 568 reveals genes that contribute to enhanced thermotolerance.the objectives of this study were to identify molecular mechanisms of thermotolerance using transposon mutants of listeria monocytogenes 568, serotype 1/2a, and to compare their thermal death kinetics at 52, 56 and 60 degrees c. sixteen tn917 transposon mutants with enhanced heat resistance were acquired from a library of 4300 mutants following a multi-step screening process. genetic regions with tn917 insertions encompassed a broad range of functionalities including; transport, metabolism, repl ...200919836093
diamide triggers mainly s thiolations in the cytoplasmic proteomes of bacillus subtilis and staphylococcus aureus.glutathione constitutes a key player in the thiol redox buffer in many organisms. however, the gram-positive bacteria bacillus subtilis and staphylococcus aureus lack this low-molecular-weight thiol. recently, we identified s-cysteinylated proteins in b. subtilis after treatment of cells with the disulfide-generating electrophile diamide. s cysteinylation is thought to protect protein thiols against irreversible oxidation to sulfinic and sulfonic acids. here we show that s thiolation occurs also ...200919837798
genetic features of resident biofilms determine attachment of listeria monocytogenes.planktonic listeria monocytogenes cells in food-processing environments tend most frequently to adhere to solid surfaces. under these conditions, they are likely to encounter resident biofilms rather than a raw solid surface. although metabolic interactions between l. monocytogenes and resident microflora have been widely studied, little is known about the biofilm properties that influence the initial fixation of l. monocytogenes to the biofilm interface. to study these properties, we created a ...200919837841
microbial induction of inflammatory bowel disease associated gene tl1a (tnfsf15) in antigen presenting cells.tl1a is a member of the tnf superfamily and its expression is increased in the mucosa of inflammatory bowel disease patients. neutralizing anti-mouse tl1a ab attenuates chronic colitis in two t-cell driven murine models, suggesting that tl1a is a central modulator of gut mucosal inflammation in inflammatory bowel disease. we showed previously that tl1a is induced by immune complexes via the fc gamma r signaling pathway. in this study, we report that multiple bacteria, including gram negative org ...200919839006
[listeriosis, a rare but severe foodborne infection].listeria monocytogenes is a gram-positive bacillus widespread in nature and responsible for human and animal infections. listeriosis is a severe and rare infection transmitted orally and vertically, frequently in the context of an underlying immunosuppression. l. monocytogenes is able to cross several barriers: intestinal mucosa, placenta and blood-brain barrier. listeriosis is associated with a range of clinical presentations: ranging from acute gastroenteritis, septicaemia, central nervous sys ...200919839454
fulminant listerial infection of the central nervous system in an otherwise healthy patient: a case report.the mortality of listerial rhombo-encephalitis exceeds 26% and may involve otherwise healthy patients. a case is presented of a man with fatal listerial infection of the central nervous system that was monitored in an intensive care unit.200919830196
bioactivities of plectranthus ecklonii constituents.plectranthus ecklonii benth. is traditionally used in south africa for treating stomach aches, nausea, vomiting and meningitis. bioassay-guided fractionation of the ethyl acetate extract of the plant led to the isolation of two known compounds, parvifloron d and parvifloron f, neither of which has been previously reported for this species. the compounds exhibited minimum inhibitory concentrations of 15.6 and 31.2 microg/ml, respectively against listeria monocytogenes, whereas the values against ...200919831023
adherence characteristics of listeria strains isolated from three ready-to-eat meat processing plants.over 1,560 non-food contact surface swabs and raw meat ingredient samples were collected from three ready-to-eat meat processing plants (520 from each plant) from 1998 to 1999, resulting in the recovery of 259 isolates of listeria obtained from postprocess areas including drains, floors, garbage bins, cart wheels, walls, equipment surfaces, tables, brooms, pallet jacks, hoses, ladders, and waste chutes. we further examined 246 of the 259 isolates for adherence phenotype and used pcr to identify ...200919833036
development and validation of an extensive growth and growth boundary model for listeria monocytogenes in lightly preserved and ready-to-eat shrimp.an existing cardinal parameter growth and growth boundary model for listeria monocytogenes (o. mejlholm and p. dalgaard, j. food prot. 70:70-84 and 2485-2497, 2007) was expanded with terms for the effects of acetic, benzoic, citric, and sorbic acids to include a total of 12 environmental parameters and their interactive effects. the new model predicted growth rates (micro(max) values) of l. monocytogenes accurately with bias and accuracy factors of 1.0 and 1.5, respectively, for 16 batches of br ...200919833037
dose of uv light required to inactivate listeria monocytogenes in distilled water, fresh brine, and spent brine.the purpose of this research was to establish the dose of uv light (253.7 nm) needed to inactivate listeria monocytogenes in distilled water, fresh brine (9% nacl), spent brine, and diluted (5, 35, and 55%) spent brine, using uridine as a chemical actinometer. strains n1-227 (isolated from hot dog batter), n3-031 (isolated from turkey franks), and r2-499 (isolated from meat) were mixed in equal proportions and suspended in each solution prepared so as to contain 10(-4) m uridine. samples were ir ...200919833038
tnfr2-deficient memory cd8 t cells provide superior protection against tumor cell growth.tnf receptor-2 (tnfr2) plays a critical role in promoting the activation and survival of naive t cells during the primary response. interestingly, anti-cd3 plus il-2 activated tnfr2(-/-) cd8 t cells are highly resistant to activation-induced cell death (aicd), which correlates with high expression levels of prosurvival molecules such as bcl-2, survivin, and cd127 (il-7ralpha). we determined whether the resistance of activated tnfr2(-/-) cd8 t cells to aicd contributes to more effective protectio ...200919841176
fat content increases the lethality of ultra-high-pressure homogenization on listeria monocytogenes in milk.listeria monocytogenes ccug 15526 was inoculated at a concentration of approximately 7.0 log(10) cfu/ml in milk samples with 0.3, 3.6, 10, and 15% fat contents. milk samples with 0.3 and 3.6% fat content were also inoculated with a lower load of approximately 3.0 log(10) cfu/ml. inoculated milk samples were subjected to a single cycle of ultra-high-pressure homogenization (uhph) treatment at 200, 300, and 400 mpa. microbiological analyses were performed 2 h after the uhph treatments and after 5, ...200919841200
preexposure to repeated low doses of zymosan increases the susceptibility to pulmonary infection in rats.chronic exposure to low levels of mold has been reported to increase susceptibility to respiratory infections. in the current study, the authors investigate the lungs' ability to clear an infection after repeated low-dose zymosan exposure. exposure was conducted at a zymosan dose of 0.6 mg/kg body weight (bw) of rat, for a total of 4 doses, via intratracheal instillation during a 2 week period. treated animals were allowed to recover for 1 week before pulmonary inoculation with listeria monocyto ...200919842846
real-time pcr detection of five prevalent bacteria causing acute meningitis. 200919845537
selenium deficiency impairs host innate immune response and induces susceptibility to listeria monocytogenes infection.susceptibility or resistance to infection with listeria monocytogenes correlates with selenium (se) deficiency in response to infection.200919852827
listeria monocytogenes acta is a key player in evading autophagic recognition.autophagy is a pivotal bulk degradation system that eliminates undesirable molecules, damaged organelles, and misfolded protein aggregates in response to diverse stimuli, including infection. autophagy acts to limit intracellular microbial growth but intracellular pathogens have evolved strategies to subvert host autophagic responses for their survival. we found that listeria monocytogenes acta, a surface protein required for actin polymerization and actin-based bacterial motility, plays a pivot ...200919855178
fabh selectivity for anteiso branched-chain fatty acid precursors in low-temperature adaptation in listeria monocytogenes.gram-positive bacteria, including listeria monocytogenes, adjust membrane fluidity by shortening the fatty acid chain length and increasing the proportional production of anteiso fatty acids at lower growth temperatures. the first condensation reaction in fatty acid biosynthesis is carried out by beta-ketoacyl-acyl carrier protein synthase iii (fabh), which determines the type of fatty acid produced in bacteria. here, we measured the initial rates of fabh-catalyzed condensation of malonyl-acyl c ...200919863661
chemical composition and antimicrobial and antioxidant activities of mentha (longifolia l. and viridis) essential oils.the study was aimed to investigate essential oil chemical composition (gas chromatography/flame ionization detection [gc-fid] and gas chromatography/mass spectrometry [gc-ms]) and antioxidant (1,1-diphenyl-2-picrylhydrazyl free radical (dpph) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulphonate [abts] assays) and antimicrobial (gram-positive and gram-negative bacteria, fungi, and yeast) activities of essential oils extracted from leaves of mentha longifolia l. and mentha viridis. gc-ms analysis ...200919895481
effects of allspice, cinnamon, and clove bud essential oils in edible apple films on physical properties and antimicrobial activities.essential oils (eos) derived from plants are rich sources of volatile terpenoids and phenolic compounds. such compounds have the potential to inactivate pathogenic bacteria on contact and in the vapor phase. edible films made from fruits or vegetables containing eos can be used commercially to protect food against contamination by pathogenic bacteria. eos from cinnamon, allspice, and clove bud plants are compatible with the sensory characteristics of apple-based edible films. these films could e ...200919895483
antibacterial effects of allspice, garlic, and oregano essential oils in tomato films determined by overlay and vapor-phase methods.physical properties as well as antimicrobial activities against escherichia coli o157:h7, salmonella enterica, and listeria monocytogenes of allspice, garlic, and oregano essential oils (eos) in tomato puree film-forming solutions (tpffs) formulated into edible films at 0.5% to 3% (w/w) concentrations were investigated in this study. antimicrobial activities were determined by 2 independent methods: overlay of the film on top of the bacteria and vapor-phase diffusion of the antimicrobial from th ...200919895486
safety and functional aspects of preselected enterococci for probiotic use in iberian dry-fermented sausages.the purpose of this study was to investigate enterococci for potential probiotic use in iberian dry-fermented sausages. a total of 15 strains isolated from iberian dry-fermented sausages, human feces, and pig feces were evaluated for their safety and functional characteristics including biogenic amine (ba) production, antibiotic susceptibility, hemolysis, virulence determinants, cell adhesion, and antimicrobial activity against foodborne pathogens. the strain enterococcus faecium se906 was able ...200919895487
gammadelta t lymphocytes producing ifngamma and il-17 in response to candida albicans or mycobacterial antigens: possible implications for acute and chronic inflammation.t lymphocytes bearing the gammadelta t cell receptor are known to play an important role in the first-line defense against viral, bacterial and fungal pathogens. two main subsets of gammadelta t cells are known, showing distinct functional behaviour: vdelta2 t lymphocytes, circulating in the peripheral blood, are involved in the response to mycobacterial infections and certain viruses, including coxsakie virus b3 and herpes simplex virus type 2. vdelta1 t cells are resident in the mucosal-associ ...200919903136
assuring growth inhibition of listerial contamination during processing and storage of traditional greek graviera cheese: compliance with the new european union regulatory criteria for listeria monocytogenes.the current microbiological regulatory criteria in the european union specify a maximum listeria monocytogenes population of 100 cfu/g allowable in ready-to-eat foods provided the product will not exceed this limit throughout its shelf life. the aim of this study was to validate the manufacturing method for traditional greek graviera cheese produced from thermized milk. initial challenge experiments evaluated the fate of inoculated l. monocytogenes (ca. 4 log cfu/ml, three-strain cocktail) in th ...200919903387
efficacy of chlorine dioxide against listeria monocytogenes in brine chilling solutions.chilled brine solutions are used by the food industry to rapidly cool ready-to-eat meat products after cooking and before packaging. chlorine dioxide (clo(2)) was investigated as an antimicrobial additive to eliminate listeria monocytogenes. several experiments were performed using brine solutions made of sodium chloride (nacl) and calcium chloride (cacl(2)) inoculated with l. monocytogenes and/or treated with 3 ppm of clo(2). first, 10 and 20% cacl(2) and nacl solutions (ph 7.0) were inoculated ...200919903388
morphology, release characteristics, and antimicrobial effect of nisin-loaded electrospun gelatin fiber mat.gelatin electrospun (e-spun) fiber mats containing nisin were produced by electrostatic spinning of gelatin-nisin in 70% (vol/vol) acetic acid aqueous solutions. varying nisin loading concentration (0 to 3% [wt/wt]) did not affect the fiber average diameter, whereas increasing gelatin concentration from 20 to 24% (wt/vol) caused an increase in the average diameter. all nisin-loaded gelatin e-spun fiber mats demonstrated inhibition against lactobacillus plantarum tistr 850. however, all fiber mat ...200919903391
prevalence and molecular diversity of listeria monocytogenes in retail establishments.as our understanding of listeria monocytogenes transmission in retail and deli operations is limited, we conducted a cross-sectional study of l. monocytogenes contamination patterns in 121 retail establishments, using testing of food and environmental samples and subtype analysis (ribotyping) of l. monocytogenes isolates. seventy-three (60%) establishments had at least one sample that tested positive for l. monocytogenes; 5 (2.7%) of the 183 food and 151 (13.0%) of the 1,161 environmental sample ...200919903398
pkctheta is required for alloreactivity and gvhd but not for immune responses toward leukemia and infection in mice.when used as therapy for hematopoietic malignancies, allogeneic bm transplantation (bmt) relies on the graft-versus-leukemia (gvl) effect to eradicate residual tumor cells through immunologic mechanisms. however, graft-versus-host disease (gvhd), which is initiated by alloreactive donor t cells that recognize mismatched major and/or minor histocompatibility antigens and cause severe damage to hematopoietic and epithelial tissues, is a potentially lethal complication of allogeneic bmt. to enhance ...200919907075
a listeria monocytogenes strain is still virulent despite nonfunctional major virulence genes.the low-virulence listeria monocytogenes strains have been previously assigned to 4 phenotypic groups. this study aimed to characterize the a23 strain, which exhibits a pulsed-field gel electrophoresis profile specific to low-virulence strains. this strain has the same causal mutations as the group iii strains and a supplementary mutation in the mpl gene, leading to the absence of internalin a expression and the presence of inactive internalin b, phosphatidyl-inositol phospholipase c, and phosph ...200919911993
il-23 is required for protection against systemic infection with listeria monocytogenes.listeria monocytogenes (lm) is a gram-positive, intracellular bacterium that can induce spontaneous abortion, septicemia, and meningitis. although it is known that neutrophils are required for elimination of the bacteria and for survival of the host, the mechanisms governing the recruitment of neutrophils to lm-infected tissues are not fully understood. we demonstrate here that il-23 and the il-17 receptor a (il-17ra), which mediates both il-17a and il-17f signaling, are necessary for resistance ...200919923464
[a case of listeria meningitis showed high levels of adenosine deaminase in cerebrospinal fluid].an 83-year-old woman developed high fever and headache for four days. she had disturbance of consciousness and was admitted to our hospital. a lumbar puncture was performed and cerebrospinal fluid (csf) analysis revealed a white blood cell count of 268/mm3 and culture became positive for listeria monocytogenes. six days after admission, the adenosine deaminase (ada) level in csf markedly elevated (43.3 iu/l) with pleocytosis, but a negative pcr test for tuberculosis in csf, sputum, gastric fluid ...200919928691
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