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low prevalence of listeria monocytogenes in human stool.listeria monocytogenes is a foodborne pathogen that is found widely in the environment and in a variety of ready-to-eat foods, yet human invasive infection is relatively rare (five cases per million people annually in the united states). despite wide exposure to this organism, little is known about the prevalence of l. monocytogenes in human stool, and it is not known whether human fecal dispersal contributes to human foodborne transmission. we cultured 827 stool specimens (well formed and loose ...200515690823
fate of pathogens present in livestock wastes spread onto fescue plots.fecal wastes from a variety of farmed livestock were inoculated with livestock isolates of escherichia coli o157, listeria monocytogenes, salmonella, campylobacter jejuni, and cryptosporidium parvum oocysts at levels representative of the levels found in naturally contaminated wastes. the wastes were subsequently spread onto a grass pasture, and the decline of each of the zoonotic agents was monitored over time. there were no significant differences among the decimal reduction times for the bact ...200515691918
bias in the listeria monocytogenes enrichment procedure: lineage 2 strains outcompete lineage 1 strains in university of vermont selective enrichments.listeria monocytogenes can be isolated from a range of food products and may cause food-borne outbreaks or sporadic cases of listeriosis. l. monocytogenes is divided into three genetic lineages and 13 serotypes. strains of three serotypes (1/2a, 1/2b, and 4b) are associated with most human cases of listeriosis. of these, strains of serotypes 1/2b and 4b belong to lineage 1, whereas strains of serotype 1/2a and many other strains isolated from foods belong to lineage 2. l. monocytogenes is isolat ...200515691954
screening for bacillus isolates in the broiler gastrointestinal tract.spores from a number of different bacillus species are currently being used as human and animal probiotics, although their mechanisms of action remain poorly understood. here we describe the isolation of 237 presumptive gut-associated bacillus spp. isolates that were obtained by heat and ethanol treatment of fecal material from organically reared broilers followed by aerobic plating. thirty-one representative isolates were characterized according to their morphological, physiological, and bioche ...200515691955
nod2-dependent regulation of innate and adaptive immunity in the intestinal tract.the gene encoding the nod2 protein is frequently mutated in crohn's disease (cd) patients, although the physiological function of nod2 in the intestine remains elusive. here we show that protective immunity mediated by nod2 recognition of bacterial muramyl dipeptide is abolished in nod2-deficient mice. these animals are susceptible to bacterial infection via the oral route but not through intravenous or peritoneal delivery. nod2 is required for the expression of a subgroup of intestinal anti-mic ...200515692051
the role of peptidoglycan in pathogenesis.bacterial pathogens rely on a variety of virulence factors to establish the colonization of a new niche. although peptidoglycan and its muropeptide derivatives have been known to possess potent biological properties, until recently the molecular bases were poorly understood. with the identification of the cytosolic surveillance mechanism mediated by the nucleotide-binding oligomerization domain (nod)1 and nod2 proteins, which detect unique peptidoglycan-derived muropeptides, these muropeptides s ...200515694856
modelling the effect of ethanol on growth rate of food spoilage moulds.the effect of ethanol (e) on the radial growth rate (mu) of food spoilage moulds (aspergillus candidus, aspergillus flavus, aspergillus niger, cladosporium cladosporioides, eurotium herbariorum, mucor circinelloides, mucor racemosus, paecilomyces variotii, penicillium chrysogenum, penicillium digitatum, rhizopus oryzae and trichoderma harzianum) was assessed in potato dextrose agar (pda) medium at a(w) 0.99, 25 degrees c. in order to model this effect, the monod type equation described previousl ...200515698687
precursor and temperature modulation of fatty acid composition and growth of listeria monocytogenes cold-sensitive mutants with transposon-interrupted branched-chain alpha-keto acid dehydrogenase.branched-chain fatty acids (bcfas) typically constitute more than 90 % of the fatty acids of listeria monocytogenes. the authors have previously described two tn917-induced, cold-sensitive, bcfa-deficient (<40 %) l. monocytogenes mutants (cld-1 and cld-2) with lowered membrane fluidity. sequence analyses revealed that tn917 was inserted into different genes of the branched-chain alpha-keto acid dehydrogenase cluster (bkd) in these two mutants. the cold-sensitivity and bcfa deficiency of cld-1, i ...200515699210
[molecular basis of listeria monocytogenes fetoplacental tropism]. 200515639011
synthesis, surface active and antimicrobial properties of new alkyl 2,6-dideoxy-l-arabino-hexopyranosides.synthesis of alkyl 2,6-dideoxy-l-arabino-hexopyranosides was accomplished by the reaction of 1,5-anhydro-2,6-dideoxy-l-arabino-hex-1-enitol with fatty alcohols in dichloromethane, catalyzed by triphenylphosphine hydrobromide. reaction with octanol and dodecanol gave the corresponding alpha-glycosides in 50% and 42% yield, the beta-glycosides in 20% and 21% yield and the alpha-anomer of the ferrier product in 10% and 9% yield, respectively. deacetylation of the alpha-/beta-glycosides with sodium ...200515639239
phosphoinositide 3-kinase is required for intracellular listeria monocytogenes actin-based motility and filopod formation.motile nonmuscle cells concentrate phosphatidylinositol 3,4,5-trisphosphate (ptdins(3,4,5)p3) and phosphatidylinositol 4,5-bisphosphate (ptdins(4,5)p2) in areas of new actin filament assembly. there is great interest in assessing the in vivo functional significance of these phosphoinositides, and we have used listeria monocytogenes to explore the contribution of ptdins(3,4,5)p3 and ptdins(4,5)p2 to its actin-based motility. in listeria-infected ptk2 cells akt-pleckstrin homology (ph)-green fluor ...200515642729
performance of a new chromogenic plating medium for the isolation of listeria monocytogenes from marine environments.aims: this study investigated the performance of a new chromogenic plating medium for the detection of listeria monocytogenes from naturally contaminated samples obtained from marine environments in morocco in comparison with the conventional plating media palcam and oxford. methods: a total of 479 marine samples (sea water, sediment and mussels) were collected from 16 littoral sites in the region of agadir (western centre of morocco). they were examined for the presence of l. monocytogenes usin ...200515644105
characterization of a mutant listeria monocytogenes strain expressing green fluorescent protein.to construct a recombinant strain of listeria monocytogenes for the expression of heterologous genes, homologous recombination was utilized for insertional mutation, targeting its listeriolysin o gene (hly). the gene encoding green fluorescent protein (gfp) was used as the indicator of heterologous gene expression. the gene gfp was inserted into hly downstream from its promoter and signal sequence by an overlapping extension polymerase chain reaction, and was then cloned into the shuttle plasmid ...200515645077
allergen immunotherapy with heat-killed listeria monocytogenes alleviates peanut and food-induced anaphylaxis in dogs.heat-killed listeria monocytogenes (hkl) potently stimulates interferon (ifn)-gamma production in cd4 t-lymphocytes, and when used as adjuvant for immunotherapy, reduces immunoglobulin (ig)e production and reverses established allergen-induced airway hyperreactivity (ahr) in a murine model of asthma. we asked if such treatment could decrease established peanut-induced anaphylaxis or cow's milk-induced food allergy in highly food-allergic dogs.200515647048
what is needed for effective antitumor immunotherapy? lessons learned using listeria monocytogenes as a live vector for hpv-associated tumors.as a vaccine vector, listeria monocytogenes targets the innate immune system, resulting in a cytokine response that enhances antigen-presenting cell function as well as inducing a th1 profile. it also enhances cell-mediated immunity by targeting antigen delivery in antigen-presenting cells to both the mhc class i pathway of exogenous presentation that activates cd8 t cells and the mhc class ii pathway that processes antigen endogenously and presents it to cd4 t cells. in this review, we describe ...200515650885
listeria monocytogenes-infected bone marrow myeloid cells promote bacterial invasion of the central nervous system.listeria monocytogenes is a facultative intracellular pathogen that is able to invade the central nervous system causing meningoencephalitis and brain abscesses. the mechanisms allowing bacteria to cross the blood-brain barrier are poorly understood. in this work, we used an experimental model of acute listeriosis in the mouse inducing a reproducible invasion of the central nervous system. at the early phase of infection, we find that bacteria invade and rapidly grow in bone marrow cells identif ...200515659061
land application of treated sewage sludge: quantifying pathogen risks from consumption of crops.to predict the number of humans in the uk infected through consumption of root crops grown on agricultural land to which treated sewage sludge has been applied in accordance with the current regulations and guidance (safe sludge matrix).200515659193
the svpa-srtb locus of listeria monocytogenes: fur-mediated iron regulation and effect on virulence.in listeria monocytogenes the promoter region of the svpa-srtb locus contains a well-conserved fur box. we characterized the iron-regulation of this locus: real-time polymerase chain reaction analyses and anti-svpa immunoblots showed that, in response to iron deprivation svpa transcription and svpa production markedly increased (80-fold and 10-fold respectively), when initiated by either the addition of the iron chelator 2,2'-bipyridyl to bhi media, or by growth in iron-restricted minimal media. ...200515661014
the actin slingshot.actin polymerization generates the force that deforms the cell membrane, pulls the cell forward and propels endosomes and bacteria within the cell. the mechanism of force generation has been probed using experimental biomimetic systems where force generation and movement occur by the same actin-polymerization processes observed in cells. the advantage of such systems over living cells is that their physical properties can be changed, such as the size of the load, its composition and its deformab ...200515661520
immune activation of type i ifns by listeria monocytogenes occurs independently of tlr4, tlr2, and receptor interacting protein 2 but involves tnfr-associated nf kappa b kinase-binding kinase 1.type i ifns are well established antiviral cytokines that have also been shown to be induced by bacteria. however, the signaling mechanisms regulating the activation of these cytokines during bacterial infections remain poorly defined. we show that although gram-negative bacteria can activate the type i ifn pathway through tlr4, the intracellular gram-positive bacterium listeria monocytogenes (lm) can do so independently of tlr4 and tlr2. furthermore, experiments using genetic mutants and chemic ...200515661922
contribution of three bile-associated loci, bsh, pva, and btlb, to gastrointestinal persistence and bile tolerance of listeria monocytogenes.listeria monocytogenes must resist the deleterious actions of bile in order to infect and subsequently colonize the human gastrointestinal tract. the molecular mechanisms used by the bacterium to resist bile and the influence of bile on pathogenesis are as yet largely unexplored. this study describes the analysis of three genes--bsh, pva, and btlb--previously annotated as bile-associated loci in the sequenced l. monocytogenes egde genome (lmo2067, lmo0446, and lmo0754, respectively). analysis of ...200515664931
pre-existing immunity to pathogenic listeria monocytogenes does not prevent induction of immune responses to feline immunodeficiency virus by a novel recombinant listeria monocytogenes vaccine.listeria monocytogenes is an attractive biologic vaccine vector against hiv because it induces a strong cell mediated immune response, can be delivered by mucosal routes, can be readily manipulated to express viral antigens, and is easy and inexpensive to produce. proof of concept studies have been performed using hiv gag expressing recombinant l. monocytogenes in the mouse. here we report the development and validation of recombinant l. monocytogenes to be evaluated in the fiv/cat model of hiv. ...200515670884
gelsolin mediates calcium-dependent disassembly of listeria actin tails.the role of intracellular ca2+ in the regulation of actin filament assembly and disassembly has not been clearly defined. we show that reduction of intracellular free ca2+ concentration ([ca2+]i) to <40 nm in listeria monocytogenes-infected, egfp-actin-transfected madin-darby canine kidney cells results in a 3-fold lengthening of actin filament tails. this increase in tail length is the consequence of marked slowing of the actin filament disassembly rate, without a significant change in assembly ...200515671163
[the contribution of system regulation of pathogenicity-determining genes expression to the virulence of facultative intracellular parasites].bacteria which belong to the group of facultative parasites are capable of intensive proliferation both outside the organism and inside eukaryotic cells, thus often causing severe human and animal illness. the necessity of quick adaptation to the alteration of conditions after intrusion into the macro-organism gave rise to the development of complex genetic systems, regulating the activity of various gene groups. the review, written by the example of two pathogen bacteria, the gram-positive list ...200515715156
contamination of chicken carcasses in gauteng, south africa, by salmonella, listeria monocytogenes and campylobacter.the presence of the foodborne pathogens, salmonella spp., listeria monocytogenes and campylobacter spp., on 99 fresh and frozen chicken carcasses sourced from various retailers in gauteng, south africa, was investigated. using culture methods, 60.6% of the carcasses were found to be contaminated with one or more pathogens, with 19.2%, 19.2% and 32.3% of the carcasses being found to harbour salmonella, l. monocytogenes and campylobacter, respectively. the extent of contamination with one or more ...200515718024
interactions of escherichia coli o157:h7, salmonella typhimurium and listeria monocytogenes plants cultivated in a gnotobiotic system.the growth and persistence of escherichia coli o157:h7, salmonella typhimurium and listeria monocytogenes on a diverse range of plant types over extended cultivation periods was studied. when introduced on the seed of carrot, cress, lettuce, radish, spinach and tomato all the pathogens became rapidly established shortly after germination, attaining cell densities of the order of 5.5-6.5 log cfu/g. in general, es. coli o157:h7 and l. monocytogenes became established and persisted at significantly ...200515718025
survival of pathogenic bacteria in pesticide solutions and on treated tomato plants.the ability of salmonella, escherichia coli o157:h7, listeria monocytogenes, and shigella to survive or grow in pesticide solutions (ambush 240ec, benlate t-n-g, bravo 500, botran 75wp, captan 80wdg, parasol, and vendex 50w) used by the horticultural industry was examined. in the laboratory, individual cultures were inoculated at 4 log cfu/ml in pesticides diluted with sterile saline to the lowest recommended spray concentrations. during 21 degrees c incubation for < or =96 h, bacterial survivor ...200515726972
determination of 5-log pathogen reduction times for heat-processed, acidified vegetable brines.recent outbreaks of acid-resistant food pathogens in acid foods, including apple cider and orange juice, have raised concerns about the safety of acidified vegetable products. we determined pasteurization times and temperatures needed to assure a 5-log reduction in the numbers of escherichia coli o157:h7, listeria monocytogenes, and salmonella strains in acidified cucumber pickle brines. cocktails of five strains of each pathogen were (separately) used for heat-inactivation studies between 50 an ...200515726973
alternative sigma factor sigmab is not essential for listeria monocytogenes surface attachment.listeria monocytogenes is a foodborne pathogen frequently isolated from the food processing environment. multiple lines of evidence suggested a possible role for the l. monocytogenes alternative transcription factor sigma b (sigmab) in surface attachment and biofilm formation. therefore, through plate count and microscopic techniques, the l. monocytogenes 10403s strain and an otherwise isogenic deltasigb strain were tested for attachment to stainless steel. analysis of microscopic images reveale ...200515726974
effectiveness of irradiation treatments in inactivating listeria monocytogenes on fresh vegetables at refrigeration temperature.ionizing radiation can be effective in controlling the growth of food spoilage and foodborne pathogenic bacteria. this study reports on an investigation of the effectiveness of irradiation treatment to eliminate listeria monocytogenes on laboratory-inoculated broccoli, cabbage, tomatoes, and mung bean sprouts. irradiation of broccoli and mung bean sprouts at 1.0 kgy resulted in reductions of approximately 4.88 and 4.57 log cfu/g, respectively, of a five-strain cocktail of l. monocytogenes. reduc ...200515726975
survival of listeria monocytogenes in experimental chorizos.chorizos-mexican-style raw-meat sausages-are a concern in california because their production in small ethnic food markets is unregulated. their formulation may cause them to appear cooked to the consumer, who may eat the raw sausage without prior proper cooking. bacterial pathogens in such products may cause illness or even death. survivability of listeria monocytogenes in chorizos was evaluated under different storage conditions selected on the basis of an initial survey of uninspected chorizo ...200515726976
simultaneous detection of listeria monocytogenes in chicken meat enrichments by pcr and reverse-transcription pcr without dna/rna isolation.environmental and food samples can be analyzed using pcr and reverse transcription (rt)-pcr techniques to discriminate between viable and nonviable cells of bacterial pathogens. here, we describe the use of a commercial lysis buffer, initially designed for mammalian cells, that permits the rapid extraction of bacterial dna and rna. the buffer is an rt-pcr-compatible lysis solution in which rna is stable and can be frozen for later use. rt-pcr is carried out directly after dnase i treatment of cr ...200515726988
incidence of listeria monocytogenes in raw seafood products in japanese retail stores.the incidence of listeria monocytogenes in raw fish, shellfish, and fish roe was investigated in seafood products collected from randomly selected retail stores in and around tokyo, japan. of the 10 samples of 208 examined found positive for l. monocytogenes by mini-vidas lmo, seven were fish roe (cod, salmon) and three were minced tuna. three serotypes (1/2a, 1/2b, 3b) were detected among the isolated strains; serotype 1/2a was predominant (8 of 10).200515726989
bacteriophages as biocontrol agents in food.bacteriophages possess attributes that appear to be attractive to those searching for novel ways to control foodborne pathogens and spoilage organisms. these phages have a history of safe use, can be highly host specific, and replicate in the presence of a host. campylobacter, salmonella, and listeria monocytogenes and various spoilage organisms have responded to phage control on some foods. however, the use of phages as biocontrol agents is complicated by factors such as an apparent requirement ...200515726992
cutting edge: microbial products elicit formation of dendritic cell aggresome-like induced structures in macrophages.in response to a maturation stimulus, dendritic cells undergo the formation of ubiquitinated protein aggregates known as dendritic cell aggresome-like induced structures (dalis). dalis are thought to act as ag storage structures, allowing for the prioritized degradation of proteins during infection. in this study, we demonstrate that murine macrophages can also form ubiquitinated protein aggregates that are indistinguishable from dalis. these were formed in a dose- and time-dependent manner, and ...200515728449
molecular analysis of resistance to streptogramin a compounds conferred by the vga proteins of staphylococci.the vga and msr resistance determinants, encoded by mobile genetic elements in various staphylococcal strains, belong to a family of atp-binding cassette (abc) proteins whose functions and structures are ill defined. their amino acid sequences are similar to those of proteins involved in the immunity of streptomycetes to the macrolide-lincosamide-streptogramin antibiotics that they produce. sequence analysis of the genomes of the gram-positive bacteria with low g+c contents revealed that lmo0919 ...200515728891
listeria monocytogenes exploits erm protein functions to efficiently spread from cell to cell.cell-to-cell spread is a fundamental step in the infection cycle of listeria monocytogenes that strictly depends on the formation of bacteria-induced protrusions. since listeria actin tails in the protrusions are tightly associated with the plasma membrane, we hypothesised that membrane-cytoskeleton linkers would be required for initiating and sustaining their formation and the subsequent cell-to-cell spread. we have found that ezrin, a member of the ezrin, radixin and moesin (erm) family that f ...200515729356
comparative activity of quinolones (ciprofloxacin, levofloxacin, moxifloxacin and garenoxacin) against extracellular and intracellular infection by listeria monocytogenes and staphylococcus aureus in j774 macrophages.quinolones accumulate in eukaryotic cells and show activity against a large array of intracellular organisms, but systematic studies aimed at examining their pharmacodynamic profile against intracellular bacteria are scarce. the present work aims at comparing intracellular-to-extracellular activities in this context.200515731197
acid-adaptation does not increase the resistance of listeria monocytogenes to irradiation in a seafood salad.stress adaptation of microbial cells enables the cells to survive better when they are subsequently exposed to other types of stresses. in the food industry, pathogens are commonly stressed during food processing and this is a concern where pathogens such as listeria monocytogenes are involved. research was conducted to determine if acid adaptation of l. monocytogenes provides resistance to ionizing irradiation. three different strains of l. monocytogenes were acid-adapted using three different ...200515734563
treatment of brain abscess caused by listeria monocytogenes in a patient with allergy to penicillin and trimethoprim-sulfamethoxazole. 200515736033
production of bacteriocins by coagulase-negative staphylococci involved in bovine mastitis.in the present study, 188 coagulase-negative staphylococcus (cns) strains were isolated from bovine mastitis cases from 56 different brazilian dairy herds, located in the southeast region of the country, and were tested for antimicrobial substance production. twelve cns strains (6.4%) exhibited antagonistic activity against a corynebacterium fimi indicator strain. most antimicrobial substances were sensitive to proteolytic enzymes suggesting that they might be bacteriocins (bac). amongst the cns ...200515737474
scant activation of cd8 t cells by antigen loaded on heat shock protein.heat shock proteins (hsp) not only function as chaperones for denatured proteins but also for antigenic peptides, thus inducing protective t cell responses. here we show that vaccination with peptide-loaded hsp70 causes initial interferon-gamma production by murine cd8 t cells but no t cell expansion. these cd8 t cells lacked cytotoxic activity in vitro and in vivo, which was not due to apoptosis. restimulation with peptide-pulsed dendritic cells both bypassed the proliferative block and suspend ...200515739167
the synthetic form of a novel chicken beta-defensin identified in silico is predominantly active against intestinal pathogens.antimicrobial peptides are essential components of innate immunity and are generally thought to act by disrupting the membrane integrity of microbes. here we report the discovery of two novel chicken beta-defensins, gallinacin (gal)-11 and gal-12, found by hidden markov model profile searching of the chicken genome. we have sequenced the genes and elucidated the 3'utr of gal-11. differential mrna expression of these novel genes has been shown across a panel of chicken tissues. gal-11 mrna was hi ...200515744537
enhanced survival of salmonella enterica in vesicles released by a soilborne tetrahymena species.nondestructive ingestion by soilborne protozoa may enhance the environmental resiliency of important bacterial pathogens and may model how such bacteria evade destruction in human macrophages. here, the interaction of salmonella enterica serovar thompson with a soilborne tetrahymena sp. isolate was examined using serovar thompson cells labeled with the green fluorescent protein. the bacteria were mixed in solution with cells of tetrahymena at several ratios. during incubation with serovar thomps ...200515746361
a novel role of il-15 in early activation of memory cd8+ ctl after reinfection.a rapid induction of effector functions in memory t cells provides rapid and intensified protection against reinfection. to determine potential roles of il-15 in early expansion and activation of memory cd8+ t cells in secondary immune response, we examined the cell division and cytotoxicity of memory cd8+ t cells expressing ova(257-264)/kb-specific tcr that were transferred into il-15-transgenic (tg) mice, il-15 knockout (ko) mice, or control c57bl/6 mice followed by challenge with recombinant ...200515749896
establishment of a universal size standard strain for use with the pulsenet standardized pulsed-field gel electrophoresis protocols: converting the national databases to the new size standard.the pulsenet national database, established by the centers for disease control and prevention in 1996, consists of pulsed-field gel electrophoresis (pfge) patterns obtained from isolates of food-borne pathogens (currently escherichia coli o157:h7, salmonella, shigella, and listeria) and textual information about the isolates. electronic images and accompanying text are submitted from over 60 u.s. public health and food regulatory agency laboratories. the pfge patterns are generated according to ...200515750058
t cells undergo rapid on/off but not on/off/on cycling of cytokine production in response to antigen.inflammatory cytokines such as ifn-gamma and tnf produced by ag-stimulated cd4(+) and cd8(+) t cells are important in defense against microbial infection. however, production of these cytokines must be tightly regulated to prevent immunopathology. previous studies, conducted with balb/c mice, have suggested that 1) cd8(+) t cells maintain ifn-gamma production but transiently produce tnf in the continued presence of ag and 2) lymphocytic choriomeningitis virus-specific and in vitro-propagated eff ...200515634891
cpg oligodeoxynucleotides enhance neonatal resistance to listeria infection.infection by listeria monocytogenes causes serious morbidity and mortality during the neonatal period. previous studies established that immunostimulatory cpg oligodeoxynucleotides (odn) can increased the resistance of adult mice to many infectious pathogens, including listeria. this work examines the capacity of cpg odn to stimulate a protective immune response in newborns. results indicate that dendritic cells, macrophages, and b cells from 3-day-old mice respond to cpg stimulation by secretin ...200515634898
design, nmr characterization and activity of a 21-residue peptide fragment of bacteriocin as-48 containing its putative membrane interacting region.bacteriocin as-48 is a 70-residue cyclic polypeptide from enterococcus faecalis that shows a broad antimicrobial spectrum against both gram-positive and gram-negative bacteria. the structure of bacteriocin as-48 consists of a globular arrangement of five helices with a high positive electrostatic potential in the region comprising helix 4, the turn linking helix 4 and 5, and the n-terminus of helix 5. this region has been considered to participate in its biological activity and in particular in ...200515635724
mechanistic study of membrane concentration and recovery of listeria monocytogenes.detection of the foodborne pathogen listeria monocytogenes requires that food samples be processed to remove proteins and lipids, concentrate microorganisms to a detectable concentration, and recover the concentrated cells in a small volume compatible with micron-scale biochips. mechanistic considerations addressed in this research include the roles of membrane structure, pore size, and detergents in maximizing recovery of cells from a complex biological fluid. the fluid in this case was a food ...200515614853
antibiotic susceptibility of listeria monocytogenes in denmark 1958-2001.in order to see whether the susceptibility of danish listeria monocytogenes strains has changed over the years we examined a collection of human isolates from the period 1958-2001. we, furthermore, wanted to compare l. monocytogenes susceptibility testing using a disc diffusion assay with mic measurements performed by the e-test. 106 strains isolated predominantly from blood cultures and cerebrospinal fluids were examined together with three reference strains. susceptibility to the following ant ...200515676012
[cerebral abscess in an immunosuppressed patient]. 200515701332
mode of action of piscicocin cs526 produced by carnobacterium piscicola cs526.piscicocin cs526 is a unique class iia bacteriocin produced by carnobacterium piscicola cs526. the mode of action against the sensitive strain listeria monocytogenes iid581 was evaluated.200515836484
characterization of a bacteriocin produced by enterococcus faecium gm-1 isolated from an infant.to partially characterize the bacteriocin produced by the gm-1 strain of enterococcus faecium, isolated from the faeces of a newborn human infant.200515836487
inactivation of escherichia coli, listeria monocytogenes, pseudomonas aeruginosa and staphylococcus aureus on stainless steel and glass surfaces by neutral electrolysed water.to ascertain the efficacy of neutral electrolysed water (new) in reducing escherichia coli, pseudomonas aeruginosa, staphylococcus aureus and listeria monocytogenes on glass and stainless steel surfaces. its effectiveness for that purpose is compared with that of a sodium hypochlorite (naclo) solution with similar ph, oxidation-reduction potential (orp) and active chlorine content.200515836736
specific molecular detection of carnobacterium piscicola sf668 in cold smoked salmon.to establish a rapid and reliable multiplex pcr (mpcr)-based method allowing specific identification of carnobacterium piscicola sf668 during storage of cold smoked salmon (css).200515836740
the listeria monocytogenes prfap2 promoter is regulated by sigma b in a growth phase dependent manner.listeria monocytogenes prfa, encoding positive regulatory factor a, is transcribed from three promoters (prfap1, prfap2, and pplca). the prfap2 promoter was previously proposed to be sigma b (sigma(b))-dependent. this hypothesis was tested by creating prfa promoter-gus transcriptional fusions in both l. monocytogenes wild-type (wt) and deltasigb backgrounds and then measuring (i) beta-glucuronidase (gus) activities; (ii) gus mrna transcript levels; and (iii) the presence or absence of gus in cel ...200515837390
comparative proteome analysis of secretory proteins from pathogenic and nonpathogenic listeria species.extracellular proteins of bacterial pathogens play a crucial role in the infection of the host. here we present the first comprehensive validation of the secretory subproteome of the gram positive pathogen listeria monocytogenes using predictive bioinformatic and experimental proteomic approaches. the previous original signal peptide (sp) prediction (glaser et al., science 2001, 294, 849-852) has been greatly improved by an in-depth analysis using seven different bioinformatic tools. subsequent ...200515838904
bacterial delivery of functional messenger rna to mammalian cells.the limited access to the nuclear compartment may constitute one of the major barriers after bacteria-mediated expression plasmid dna delivery to eukaryotic cells. alternatively, a self-destructing listeria monocytogenes strain was used to release translation-competent mrna directly into the cytosol of epithelial cells, macrophages and human dendritic cells. enhanced green fluorescent protein (egfp)-encoding mrna, adapted for translation in mammalian cells by linking an ires element to the 5'-en ...200515839900
reducing the stimulation of cd8+ t cells during infection with intracellular bacteria promotes differentiation primarily into a central (cd62lhighcd44high) subset.during infection with lymphocytic choriomeningitis virus, cd8(+) t cells differentiate rapidly into effectors (cd62l(low)cd44(high)) that differentiate further into the central memory phenotype (cd62l(high)cd44(high)) gradually. to evaluate whether this cd8(+) t cell differentiation program operates in all infection models, we evaluated cd8(+) t cell differentiation during infection of mice with recombinant intracellular bacteria, listeria monocytogenes (lm) and mycobacterium bovis (bcg), expres ...200515843531
impact of antimicrobial ingredients and irradiation on the survival of listeria monocytogenes and the quality of ready-to-eat turkey ham.irradiation is an effective technology in eliminating listeria monocytogenes, but it induces quality changes in meat products at or above specific radiation doses. to minimize irradiation-induced quality changes, only low irradiation doses are recommended. however, low-dose irradiation provides a chance for some pathogens to survive and proliferate during prolonged storage. to solve this problem, antimicrobial ingredients [2% sodium lactate (sl), 0.1% sodium diacetate (sda), 0.1% potassium benzo ...200515844819
listeria monocytogenes skin infection with cerebritis and haemophagocytosis syndrome in a bone marrow transplant recipient.in this report, we describe unusual and unreported manifestations of listeria monocytogenes infection in a bone marrow transplant recipient, including cutaneous infection with an hamophagocytosis syndrome and cerebritis. l. monocytogenes occurred despite a broad spectrum antibiotherapy. l. monocytogenes was isolated from a skin biopsy. outcome was favorable with amoxicillin and gentamicin therapy. l. monocytogenes infection should be suspected in patients with cerebritis despite large spectrum a ...200515845437
molecular cloning and characterization of three beta-defensins from canine testes.mammalian beta-defensins are small cationic peptides possessing broad antimicrobial and physiological activities. because dogs are particularly resilient to sexually transmitted diseases, it has been proposed that their antimicrobial peptide repertoire might provide insight into novel antimicrobial therapeutics and treatment regimens. to investigate this proposal, we cloned the full-length cdna of three canine beta-defensin isoforms (cbd-1, -2, and -3) from canine testicular tissues. their predi ...200515845463
synthetic toll-like receptor 4 agonists stimulate innate resistance to infectious challenge.a compound family of synthetic lipid a mimetics (termed the aminoalkyl glucosaminide phosphates [agps]) was evaluated in murine infectious disease models of protection against challenge with listeria monocytogenes and influenza virus. for the listeria model, intravenous administration of agps was followed by intravenous bacterial challenge 24 h later. spleens were harvested 2 days postchallenge for the enumeration of cfu. for the influenza virus model, mice were challenged with virus via the int ...200515845512
construction and characterization of listeria monocytogenes mutants with in-frame deletions in the response regulator genes identified in the genome sequence.two-component systems are widely distributed in prokaryotes where they control gene expression in response to diverse stimuli. to study the role of the sixteen putative two-component systems of listeria monocytogenes systematically, in frame deletions were introduced into 15 out of the 16 response regulator genes and the resulting mutants were characterized. with one exception the deletion of the individual response regulator genes has only minor effects on in vitro and in vivo growth of the bac ...200515845524
brain stem encephalitis in listeriosis.serious infection with the bacterium l. monocytogenes mainly manifests as sepsis and/or meningitis. a particular entity is listeria brain stem encephalitis, which is characterized by progressive brain stem deficits. the condition is fatal unless early treated. the purpose of the present study was to assess the incidence of brain stem encephalitis in a population-based listeriosis material. medical records from 212 of the 240 patients with serious listeriosis reported in norway from 1977 to 2000, ...200515849051
differential requirements for the chemokine receptor ccr7 in t cell activation during listeria monocytogenes infection.effective priming of t cell responses depends on cognate interactions between naive t cells and professional antigen-presenting cells (apcs). this contact is the result of highly coordinated migration processes, in which the chemokine receptor ccr7 and its ligands, ccl19 and ccl21, play a central role. we used the murine listeria monocytogenes infection model to characterize the role of the ccr7/ccr7 ligand system in the generation of t cell responses during bacterial infection. we demonstrate t ...200515851484
reduction of listeria monocytogenes populations during exposure to a simulated gastric fluid following storage of inoculated frankfurters formulated and treated with preservatives.the effect of a simulated gastric fluid (adjusted to ph 1.0 with hcl) on listeria monocytogenes, inoculated postprocessing on pork frankfurters formulated with sodium lactate (sl) and sodium diacetate (sd) and not dipped or dipped in solutions of lactic acid or acetic acid, was evaluated during storage of the frankfurters at 10 degrees c for 40 days. pork frankfurters containing 1.8% sl, 0.25% sd, 1.8% sl+0.125% sd, or 1.8% sl+0.25% sd were inoculated with 10(2)-10(3) cfu/cm2 of a 10-strain prep ...200515808365
quantitative detection of listeria monocytogenes in biofilms by real-time pcr.a quantitative method based on a real-time pcr assay to enumerate listeria monocytogenes in biofilms was developed. the specificity for l. monocytogenes of primers targeting the listeriolysin gene was demonstrated using a sybr green i real-time pcr assay. the number of l. monocytogenes detected growing in biofilms was 6 x 10(2) cfu/cm2.200515812058
human dendritic cells process and present listeria antigens for in vitro priming of autologous cd4+ t lymphocytes.the role of human dendritic cells (dc) in the immune response toward intracellularly growing listeria was analyzed under in vitro conditions using several morphological and functional methods. dc incubated with listeria innocua and l. monocytogenes, respectively, readily phagocytosed the bacteria. listeria did not impair viability and immunogenic potential of human dc. listerial antigens were found to be processed within the lysosomal compartment of dc and colocalized with major histocompatibili ...200515812647
translation elongation factor ef-tu is a target for stp, a serine-threonine phosphatase involved in virulence of listeria monocytogenes.listeria monocytogenes is a pathogen that causes listeriosis, a severe food-borne infection. this bacterium, in order to survive and grow in the multiple conditions encountered in the host and the environment, has evolved a large number of regulatory elements, in particular many signal transduction systems based on reversible phosphorylation. the genome sequence has revealed genes for 16 putative two-component systems, four putative tyrosine phosphatases, three putative serine-threonine kinases ...200515813732
the mutation g145s in prfa, a key virulence regulator of listeria monocytogenes, increases dna-binding affinity by stabilizing the hth motif.listeria monocytogenes, a gram-positive, facultative intracellular human pathogen, causes systemic infections with high mortality rate. the majority of the known pathogenicity factors of l. monocytogenes is regulated by a single transcription factor, prfa. hyperhaemolytic laboratory strains of l. monocytogenes express the constitutively active mutant prfa(g145s) inducing virulence gene overexpression independent of environmental conditions. prfa belongs to the crp/fnr family of transcription fac ...200515813735
ipr1 gene mediates innate immunity to tuberculosis.an estimated eight million people are infected each year with the pathogen mycobacterium tuberculosis, and more than two million die annually. yet only about 10% of those infected develop tuberculosis. genetic variation within host populations is known to be significant in humans and animals, but the nature of genetic control of host resistance to tuberculosis remains poorly understood. previously we mapped a new genetic locus on mouse chromosome 1, designated sst1 (for supersusceptibility to tu ...200515815631
engineered e. coli delivers therapeutic genes to the colonic mucosa.taking advantage of the proximity of bowel mucosa to luminal bacteria, we have attempted to deliver a therapeutic gene to the colonic mucosa by oral administration of an invasive and non-pathogenic escherichia coli. e. coli diamenopimelate (dap) auxotroph, harboring plasmid pgb2omegainv-hly, express the inv gene from yersinia pseudotubercolosis that confers the ability to invade nonprofessional phagocytic cells and the hly gene from listeria monocytogenes that allows expression of lystreriolysin ...200515815705
distinct in vivo dendritic cell activation by live versus killed listeria monocytogenes.immunization of mice with live or heat-killed listeria monocytogenes (hklm) efficiently primes pathogen-specific cd8(+) t cells. t lymphocytes primed by hklm, however, undergo attenuated proliferation and do not fully differentiate. thus, only infection with live bacteria induces long-term, cd8(+) t cell-mediated protective immunity. in this study we demonstrate that live and heat-killed bacteria, while both associating with mac-3(+)cd11b(hi) cells, localize to distinct splenic areas following i ...200515816001
identification of the gene encoding a 38-kilodalton immunogenic and protective antigen of streptococcus suis.in our continued effort to search for a streptococcus suis protein(s) that can serve as a vaccine candidate or a diagnostic reagent, we constructed and screened a gene library with a polyclonal antibody raised against the whole-cell protein of s. suis type 2. a clone that reacted with the antibody was identified and characterized. analysis revealed that the gene encoding the protein is localized within a 2.0-kbp ecori dna fragment. the nucleotide sequence contained an open reading frame that enc ...200515817754
murine pulmonary infection with listeria monocytogenes: differential susceptibility of balb/c, c57bl/6 and dba/2 mice.murine listeriosis is a paradigm to understand host pathogen interactions. airway infections with listeria monocytogenes, although representing a serious problem in early onset neonatal listeriosis, has not been investigated in detail in animal models so far. here, the susceptibility of balb/c, dba/2 and c57bl/6 mice towards an intratracheal (i.t.) infection with virulent l. monocytogenes egde and the attenuated variant l. monocytogenes egd hlyw491a(perl3-cmvgfp) is reported. the course of infec ...200515820148
multistate outbreak of listeria monocytogenes infection linked to delicatessen turkey meat.despite a decreasing incidence of listeriosis in the united states, molecular subtyping has increased the number of recognized outbreaks. in september 2000, the new york city department of health identified a cluster of infections caused by listeria monocytogenes isolates with identical molecular subtypes by pulsed-field gel electrophoresis (pfge) and ribotyping.200515824987
gastroenteritis due to listeria monocytogenes.it has been known for a long time that many patients experience diarrhea antecedent to the development of bacteremia or meningoencephalitis due to listeria monocytogenes, but it was only recently that convincing evidence was obtained that this organism can cause acute, self-limited, febrile gastroenteritis in healthy persons. at least 7 outbreaks of foodborne gastroenteritis due to l. monocytogenes have been reported. illness typically occurs 24 h after ingestion of a large inoculum of bacteria ...200515825036
the antimicrobial activity of extracts of the lichen hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent.the antimicrobial activity and the mic values of the diethyl ether, acetone, chloroform, petroleum ether, and ethanol extracts of the lichen hypogymnia tubulosa and its 3-hydroxyphysodic acid constituent have been investigated against some microorganisms. at least one of the extracts or 3-hydroxyphysodic acid showed antimicrobial activity against aeromonas hydrophila, bacillus cereus, bacillus subtilis, escherichia coli, klebsiella pneumoniae, listeria monocytogenes, proteus vulgaris, salmonella ...200515787241
uncertainty distribution associated with estimating a proportion in microbial risk assessment.the uncertainty associated with estimates should be taken into account in quantitative risk assessment. each input's uncertainty can be characterized through a probabilistic distribution for use under monte carlo simulations. in this study, the sampling uncertainty associated with estimating a low proportion on the basis of a small sample size was considered. a common application in microbial risk assessment is the estimation of a prevalence, proportion of contaminated food products, on the basi ...200515787755
meta-analysis of food safety information based on a combination of a relational database and a predictive modeling tool.the management of microbial risk in food products requires the ability to predict growth kinetics of pathogenic microorganisms in the event of contamination and growth initiation. useful data for assessing these issues may be found in the literature or from experimental results. however, the large number and variety of data make further development difficult. statistical techniques, such as meta-analysis, are then useful to realize synthesis of a set of distinct but similar experiences. moreover ...200515787758
elimination of escherichia coli o 157 : h7 and listeria monocytogenes from raw beef sausage by gamma-irradiation.the effectiveness of low gamma-irradiation doses in the destruction of escherichia coli o 157 : h7 and listeria monocytogenes in raw beef sausages was investigated. raw samples of fresh manufactured beef sausage were subjected to gamma-irradiation at doses of 0, 1, 2, and 3 kgy. then samples were cold-stored (4 +/- 1 degrees c) for 12 days and the effects of irradiation and storage on the counts of these harmful bacteria were studied. moreover, the effects of irradiation and storage on the perce ...200515789371
listeria monocytogenes meningitis in a patient receiving etanercept for still's disease. 200515789900
septic arthritis due to listeria monocytogenes in a patient receiving etanercept. 200515751076
acid-tolerant listeria monocytogenes persist in a model food system fermented with nisin-producing bacteria.to investigate the induction of the acid tolerance response (atr) in listeria monocytogenes and to assess the persistence of the pathogen in broth fermented using a nisin-producing starter culture.200515752211
detection of viable and dead listeria monocytogenes on gouda-like cheeses by real-time pcr.surface contamination by listeria monocytogenes of gouda-like cheeses during processing represents a potential public health problem. the aim of this work was to develop novel real-time pcr diagnostics to detect the presence of viable, dead or viable but not culturable (vbnc) cells on gouda-like cheeses.200515752222
the dps-like protein fri of listeria monocytogenes promotes stress tolerance and intracellular multiplication in macrophage-like cells.members of the ferritin-like dps protein family are found in a number of bacterial species, where they demonstrate the potential to bind iron, and have been implicated in tolerance to oxidative stress. in this study of the food-borne pathogen listeria monocytogenes, the fri gene encoding a dps homologue was deleted, and, compared to wild-type cells, it was found that the resulting mutant was less resistant to hydrogen peroxide, and demonstrated reduced survival following long-term (7-11 days) in ...200515758237
a defective th1 response of the spleen in the initial phase may explain why splenectomy helps prevent a listeria infection.listeria monocytogenes (listeria) are known to grow and proliferate in the liver while a splenectomy induces host resistance against a listeria infection despite the fact that a splenectomy inhibits the th1 response. therefore, the mechanism by which a splenectomy helps to prevent the growth of listeria still remains to be elucidated. after an i.v. challenge of listeria (1 x 10(6) cfu) in c57bl/6 mice, listeria rapidly increased in the spleen but not in the liver until 48 h. however, after this ...200515762870
evidence for involvement of peptidoglycan in the triggering of an oxidative burst by listeria monocytogenes in phagocytes.we have shown previously that in listeric encephalitis of cattle and rats, nitrotyrosine was produced in microabscesses, implying that both superoxide anion (o(2) (-)) and nitric oxide (no) are present and react with each other. evidence of local synthesis of no by macrophages was provided, but the source of o(2) (-) remained unknown. here we have examined whether phagocytes exposed to viable and heat-killed listeria monocytogenes (lmdelta) produce o(2) (-) and, if so, whether this results from ...200515762877
[brain abscesses due to listeria monocytogenes].listeria monocytogenes is a gram-positive bacillus which causes sporadic infections in immunocompromised humans, with a special propensity for the central nervous system, in the form of acute, subacute or chronic meningitis, rhombencephalitis or abscesses in the brain or spinal cord. the final diagnosis is established by germ culture in blood or in cerebrospinal fluid (csf). preferred treatment is ampicillin in association with aminoglycosides.200515765316
[sepsis caused by listeria monocytogenes related with the use of infliximab]. 200515766516
inhibition of rab5a exchange activity is a key step for listeria monocytogenes survival.listeria monocytogenes (lm) modifies the phagocytic compartment by targeting rab5a function through an unknown mechanism. inhibition of rab5a exchange by lm can be considered the main virulence mechanism as it favours viability of the parasite within the phagosome as well as the exclusion of putative listericidal lysosomal proteases such as cathepsin-d. the significance of this survival mechanism is evidenced by the overexpression of rab5a mutants in cho cells that promoted gdp exchange on rab5a ...200515702993
molecular and experimental virulence of listeria monocytogenes strains isolated from cases with invasive listeriosis and febrile gastroenteritis.we analyzed 27 listeria monocytogenes strains of serotypes 1/2b and 4b, from invasive and gastroenteric listeriosis, for molecular and experimental virulence. molecular virulence was tested by pcr for the presence of 8 major virulence-associated genes and genetic polymorphisms through restriction enzyme analysis; genomic dna typing using pulsed-field gel electrophoresis was also performed. experimental virulence was evaluated through intra-peritoneal and intra-gastric mouse virulence assays. our ...200515708319
dna prime listeria boost induces a cellular immune response to siv antigens in the rhesus macaque model that is capable of limited suppression of siv239 viral replication.dna vaccines and recombinant listeria monocytogenes that express and secrete siv gag and env antigens were combined in a nonhuman primate prime-boost immunogenicity study followed by a challenge with siv239. we report that recombinant dna vaccine delivered intramuscularly, and recombinant l. monocytogenes delivered orally each individually have the ability to induce cd8+ and cd4+ t cell immune responses in a nonhuman primate. four rhesus monkeys were immunized at weeks 0, 4, 8, and 12 with the p ...200515708595
evolutionary history of the genus listeria and its virulence genes.the genus listeria contains the two pathogenic species listeria monocytogenes and listeria ivanovii and the four apparently apathogenic species listeria innocua, listeria seeligeri, listeria welshimeri, and listeria grayi. pathogenicity of the former two species is enabled by an approximately 9 kb virulence gene cluster which is also present in a modified form in l. seeligeri. for all listeria species, the sequence of the virulence gene cluster locus and its flanking regions was either determine ...200515709360
listeria monocytogenes in the chinese food system: strain characterization through partial acta sequencing and tissue-culture pathogenicity assays.human listeriosis is generally caused by consumption of ready-to-eat (rte) foods that are stored for extended periods of time at refrigeration temperatures and that permit the growth of the causative agent, listeria monocytogenes. food-consumption patterns in china are undergoing rapid changes and more regular consumption of refrigerated-storage rte foods may increase the risk of human listeriosis. in total, 40 l. monocytogenes isolates were obtained from food (n=32) and sewage (n=6) samples and ...200515713604
outbreak of listeriosis among mexican immigrants as a result of consumption of illicitly produced mexican-style cheese.in 2000, an outbreak of listeriosis among hispanic persons was identified in winston-salem, north carolina. the objectives of the present study were to identify the source of, strains associated with, and risk factors for listeria monocytogenes infection for patients affected by the outbreak.200515714412
the role of tcr stimulation and tgf-beta in controlling the expression of cd94/nkg2a receptors on cd8 t cells.following antigen recognition, murine cd8 t cells express cd94/nkg2a receptors. our results show that this up-regulation occurs rapidly in vitro and is accompanied by an approximately 8-fold increase in cd94 and approximately 125-fold increase in nkg2a mrna. in contrast, only a twofold increase in nkg2c mrna is noted. the addition of tgf-beta, but not il-10, il-12 or il-15, leads to a further increase in cell membrane expression of these receptors, as well as a approximately 6-fold increase in m ...200515714583
wasp-related proteins, abi1 and ena/vasp are required for listeria invasion induced by the met receptor.internalisation of the pathogenic bacterium listeria monocytogenes involves interactions between the invasion protein inlb and the hepatocyte growth factor receptor, met. using colocalisation studies, dominant-negative constructs and small interfering rna (sirna), we demonstrate a cell-type-dependent requirement for various wasp-related proteins in listeria entry and inlb-induced membrane ruffling. the wave2 isoform is essential for inlb-induced cytoskeletal rearrangements in vero cells. in hela ...200515769844
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