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microbial changes and growth of listeria monocytogenes during chilled storage of brined shrimp (pandalus borealis).thirteen storage trials and ten challenge tests were carried out to examine microbial changes, spoilage and the potential growth of listeria monocytogenes in brined shrimp (pandalus borealis). shrimp in brine as well as brined and drained shrimp in modified atmosphere packaging (map) were produced and studied. different recipes were used to study the effect of preserving parameters (organic acids, ph and nacl) on growth of microorganisms and shelf life at 7-8 degrees c or 12 degrees c. particula ...200818456355
evaluation of an enumeration method for listeria monocytogenes at low contamination levels in cold-smoked salmon.for the enumeration of listeria monocytogenes in cold-smoked salmon, a sensitive enumeration method, based on membrane filtration followed by transfer of the filter on a selective medium has been recently developed (gnanou besse et al., 2004, a contribution to the improvement of l. monocytogenes enumeration in cold-smoked salmon. international journal of food microbiology, 91, 119-127). the aim of the study was to assess the performance of this enumeration method through an inter-laboratory stud ...200818456358
the two-component system cesrk controls the transcriptional induction of cell envelope-related genes in listeria monocytogenes in response to cell wall-acting antibiotics.the two-component system cesrk of listeria monocytogenes responds to cell wall-acting antibiotics. we show here that cesrk controls the transcription of several cell envelope-related genes. the cesrk-dependent induction of these genes may be viewed as an attempt by l. monocytogenes to protect itself against the damaging effects of cell wall-acting antibiotics.200818456805
development of a multilocus variable-number of tandem repeat typing method for listeria monocytogenes serotype 4b strains.listeria monocytogenes serotype 4b strains have been identified as the causative agent in many human listeriosis epidemics as well as in a considerable number of sporadic cases. due to the genetic homogeneity of serotype 4b isolates, development of rapid subtyping methods with high discriminatory power for serotype 4b isolates is required to allow for improved outbreak detection and source tracking. in this study, multilocus variable-number tandem repeat analysis (mlva) was developed and used to ...200818457891
identification of listeria innocua surrogates for listeria monocytogenes in hamburger patties.listeria innocua m1 has been used by many researchers as a nonpathogenic thermal processing surrogate for listeria monocytogenes. however, l. innocua m1 has been criticized because its thermal survivability characteristics are not as closely parallel to l. monocytogenes as some would like in a variety of foods and processing conditions. the present study was conducted to compare multiple l. innocua and l. monocytogenes strains to validate l. innocua m1 as the ideal surrogate under high-temperatu ...200818460133
characterization of bacteriocin-coated antimicrobial polyethylene films by atomic force microscopy.antimicrobial agents can be used to give antimicrobial properties to polymeric materials used to envelope foods for packaging purposes. in this study, we exploited an atomic force microscopy (afm) analysis for the characterization of plastic films activated with antimicrobial agents. the aim was to acquire information on the distribution of the antimicrobials on plastic materials with the ultimate scope of understanding the mechanisms of interaction between antimicrobials and materials to be use ...200818460145
survival of bacterial pathogens during the thermophilic anaerobic digestion of biowaste: laboratory experiments and in situ validation.anaerobic digestion is continually gaining importance for the processing of the organic fraction of municipal solid wastes. although methods for studying the survival of pathogen exist, these methods often need adaptations, are expensive, time consuming or generally not well suited for the harsh conditions within an anaerobic digestion system. in the present study we investigated the applicability of commercially available, mechanically stable and inexpensive pathogen carriers to validate in sit ...200818460419
cd14 works with toll-like receptor 2 to contribute to recognition and control of listeria monocytogenes infection.toll-like receptor 2 (tlr2) signaling has been shown to contribute to resistance to listeria monocytogenes infection, as tlr2-deficient mice have a heightened susceptibility to infection with this organism. because cd14 may associate with tlr2, we investigated the role of cd14 in listeria responses. in both cd14-deficient and tlr2-deficient macrophages, nuclear factor kappab translocation; cd40 and cd86; and the production of interleukin (il)-12, il-6, tumor necrosis factor, and nitric oxide are ...200818462086
listeria monocytogenes: epidemiology, human disease, and mechanisms of brain invasion.listeria monocytogenes is a facultative intracellular bacterium that has predilection for causing central nervous systemic infections in humans and domesticated animals. this pathogen can be found worldwide in the food supply and most l. monocytogenes infections are acquired through ingestion of contaminated food. the main clinical syndromes caused by l. monocytogenes include febrile gastroenteritis, perinatal infection, and systemic infections marked by central nervous system infections with or ...200818462388
antimicrobial activity of some new thioureides derived from 2-(4-chlorophenoxymethyl)benzoic acid.we report here the characterisation of eight newly synthesized thioureides of 2-(4-chlorophenoxymethyl)-benzoic acid and the evaluation of the in vitro antimicrobial activity of the new compounds against gram-positive [listeria monocytogenes,staphylococcus aureus, bacillus subtilis], gram-negative [psedomonas aeruginosa,escherichia coli, salmonella enteritidis], as well as candida spp., using both reference and clinical multidrug resistant strains to establish the minimal inhibitory concentratio ...200818463566
effect of ethylenediaminetetraacetate and lysozyme on the antimicrobial activity of ovotransferrin against listeria monocytogenes.this study evaluated the effect of edta and lysozyme on the antibacterial activities of activated ovotransferrin against 5 strains of listeria monocytogenes. first, a disc test was performed to screen the concentrations of edta or lysozyme that showed antibacterial activities in ovotransferrin (o) or ovotransferrin in 100 mm nahco3 (os) solution. turbidity and viability tests were conducted using o or os solution combined with either lysozyme (ol and osl) or edta (oe and ose). also, os combined ...200818648062
stable integration vector for nutrient broth-based selection of attenuated listeria monocytogenes strains with recombinant antigen expression.recombinant listeria monocytogenes strains induce strong cellular immune responses and may prove useful for antigen delivery for the vaccination of humans. however, the genetic systems currently available for the stable expression of recombinant antigens by l. monocytogenes rely on the use of antibiotic resistance genes. we report on a derivative, ppl2dalglna, of the listeria monocytogenes ppl2 integration vector that completely lacks drug resistance genes. the selectable markers in ppl2dalglna ...200818650400
pathogenesis of listeria-infected drosophila wntd mutants is associated with elevated levels of the novel immunity gene edin.drosophila melanogaster mount an effective innate immune response against invading microorganisms, but can eventually succumb to persistent pathogenic infections. understanding of this pathogenesis is limited, but it appears that host factors, induced by microbes, can have a direct cost to the host organism. mutations in wntd cause susceptibility to listeria monocytogenes infection, apparently through the derepression of toll-dorsal target genes, some of which are deleterious to survival. here, ...200818654628
in vitro inhibitory effect of cranberry (vaccinium macrocarpom ait.) juice on pathogenic microorganisms.the purpose of this study was to determine the inhibitory effects of cranberry juice on pathogenic microorganisms. the microorganisms analyzed were escherichia coli from patients with urinary infections, salmonella spp., listeria monocytogenes, pseudomonas aeruginosa, and staphylococcus aureus. the disc method was used to determine the sensitivity of bacteria to cranberry juice (cj, both concentrated and diluted). a lawn of 10(6) cfu/ml was grown on agar surfaces in petri dishes and on whatman d ...200818663959
nisin inducible production of listeriolysin o in lactococcus lactis nz9000.abstract:200818664263
the degu orphan response regulator of listeria monocytogenes autorepresses its own synthesis and is required for bacterial motility, virulence and biofilm formation.the gram-positive intracellular pathogen listeria monocytogenes is endowed with 17 sets of genes encoding two-component systems. l. monocytogenes is closely related to the gram-positive model bacterium bacillus subtilis, in which we have shown previously that the degs/degu system plays a central role in controlling stationary phase adaptive responses, including degradative enzyme synthesis and competence. although an orthologue of the degu response regulator is present in l. monocytogenes, the g ...200818667558
inactivation of listeria monocytogenes in brine and saline by alternating high-voltage pulsed current.the inactivating efficiency of alternating high-voltage pulsed (ahvp) current was investigated in brine (20 w/v% nacl) and saline (0.9 w/v% nacl) inoculated with 1x 10(7) cells/ml of listeria monocytogenes. ahvp current at 12 v with 1 pulse completely inactivated l. monocytogenes in brine within 3 ms, while the bacteria in saline were fully inactivated by 10-pulsed electric treatment at 12 v within the same time. electron microscopic observation demonstrated substantial structural damage of elec ...200818667856
listeria monocytogenes multidrug resistance transporters activate a cytosolic surveillance pathway of innate immunity.to gain insight into the interaction of intracellular pathogens with host innate immune pathways, we performed an unbiased genetic screen of listeria monocytogenes mutants that induced an enhanced or diminished host innate immune response. here, we show that the major facilitator superfamily of bacterial multidrug resistance transporters (mdrs) controlled the magnitude of a host cytosolic surveillance pathway, leading to the production of several cytokines, including type i ifn. mutations mappin ...200818632558
regional variations in paneth cell antimicrobial peptide expression along the mouse intestinal tract.enteric antimicrobial peptides secreted from paneth cells, including alpha-defensins (in mice named cryptdins), are key effector molecules of innate immunity in the small intestine. the importance of paneth cells alpha-defensins emerged from studies of enteric bacterial infection in genetically modified mice, as well as from recent studies linking reduced levels of these alpha-defensins to crohn's disease localized to the ileum. however, analysis of expression of paneth cell alpha-defensins is i ...200818637162
ifn-gamma induces the erosion of preexisting cd8 t cell memory during infection with a heterologous intracellular bacterium.memory t cells are critical for the control of intracellular pathogens and require few signals for maintenance; however, erosion of established preexisting memory cd8(+) t cells has been shown to occur during infection with heterologous viral infections. we evaluated whether this also occurs during infection with various intracellular bacteria and what mechanisms may be involved. we demonstrate that erosion of established memory is also induced during infection of mice with various intracellular ...200818641306
lipoproteins of listeria monocytogenes are critical for virulence and tlr2-mediated immune activation.numerous cell surface components of listeria influence and regulate innate immune recognition and virulence. here, we demonstrate that lipidation of prelipoproteins in listeria monocytogenes is required to promote nf-kappab activation via tlr2. in hela cells transiently expressing tlr2, l. monocytogenes and listeria innocua mutants lacking the prolipoprotein diacylglyceryl transferase (lgt) gene are unable to induce tlr2-dependent activation of nf-kappab, a property intrinsic to their isogenic p ...200818641340
adhesion of the probiotic strains enterococcus mundtii st4sa and lactobacillus plantarum 423 to caco-2 cells under conditions simulating the intestinal tract, and in the presence of antibiotics and anti-inflammatory medicaments.adhesion of enterococcus mundtii st4sa and lactobacillus plantarum 423 to caco-2 (human carcinoma epithelial) cells was visualized by fluorescent staining. both strains showed good adhesion compared to l. casei mb1, l. casei shirota, l. johnsonii la1 and l. rhamnosus gg. no correlation was found between hydrophobicity, aggregation and adhesion to caco-2 cells. presence of antibiotics and anti-inflammatory medicaments reduced adhesion of bacterial strains to caco-2 cells. proteins sensitive to pe ...200818641972
the anti-inflammatory drug diclofenac retains anti-listerial activity in vivo.the interactions between nonsteroidal anti-inflammatory drugs (nsaid) and listeria monocytogenes have not been sufficiently documented to date. the aim of this study was to investigate the possible effects of diclofenac (dc) in a murine listerial infection model.200818643914
a 'fly-by' killing with a primordial cellular weapon. 200818645586
transcriptome analysis of organisms with food safety relevance.transcriptome analysis using microarrays has become a powerful tool to better understand the process of disease and other complex biological processes such as food spoilage and biofilm formation. this review is divided into two basic sections: 1) a short history and description of microarrays and 2) a discussion of studies involving bacterial food safety pathogens that focused on whole genome transcript analysis. not included are the many studies using microarrays to identify, diagnose, or genet ...200818673071
[cryptococcosis].cryptococcus neoformans infection is an opportunistic infection affecting mainly patients lacking cell mediated immunity whose incidence has dramatically risen with the advent of hiv infection. this infection has rarely been reported in patients with humoral immunity deficiencies. we report two patients with cryptococcus neoformans infection with a fatal outcome: a man with disseminated criptococcosis leading to the diagnosis of aids; and a woman with stage iii- b k light chains multiple myeloma ...200818674423
liver invariant nkt cells and listeriosis.the invariant (i) nkt cells represent unique t lymphocytes expressing tcrvalpha14. although inkt cells have been regarded as t lymphocytes expressing nk1.1, they do not consistently express this marker. nk1.1 allows recognition of "missing-self" and thus controls inhibition/activation of inkt cells. it is thus tempting to assume that inkt cells participate in the regulation of host immune responses during microbial infection by controlling nk1.1 expression. these findings shed light on the uniqu ...200818674633
a novel prfa mutation that promotes listeria monocytogenes cytosol entry but reduces bacterial spread and cytotoxicity.listeria monocytogenes is an environmental bacterium that becomes a pathogen following ingestion by a mammalian host. the transition from environmental organism to pathogen requires significant changes in gene expression, including the increased expression of gene products that contribute to bacterial growth within host cells. prfa is an l. monocytogenes transcriptional regulator that becomes activated upon bacterial entry into mammalian cells and induces the expression of gene products required ...200818675335
towards on-site pathogen detection using antibody-based sensors.in this paper, the recent progress within biosensors for plant pathogen detection will be reviewed. bio-recognition layers on sensors can be designed in various ways, however the most popular approach is to immobilise antibodies for specific capture of analytes. focus will be put on antibody surface-immobilisation strategies as well as the use of antibodies in the widely used sensors, quartz crystal microbalance, surface plasmon resonance and cantilevers. we will describe the available data on a ...200818675543
the detection of food soils and cells on stainless steel using industrial methods: uv illumination and atp bioluminescence.open food contact surfaces were subjected to organic soiling to provide a source for transfer of microbial cells. rapid industrial methods used for the detection of residual cells and soil e.g. atp (adenosine triphosphate) bioluminescence and an ultraviolet (uv) light detection method were assessed for their ability to detect organic soils, or organic soil-cell mix on surfaces. a range of soils (complex [meat extract, fish extract, cottage cheese extract]; oils [cholesterol, fish oil, mixed fatt ...200818678428
enumeration of cytotoxic cd8 t cells ex vivo during the response to listeria monocytogenes infection.cytotoxicity is a key effector function of cd8 t cells. however, what proportion of antigen-specific cd8 t cells in vivo exert cytotoxic activity during a functional cd8 t-cell response to infection still remains unknown. we used the lysispot assay to directly enumerate cytotoxic cd8 t cells from the spleen ex vivo during the immune response to infection with the intracellular bacterium listeria monocytogenes. we demonstrate that not all antigen-responsive gamma interferon (ifn-gamma)-secreting ...200818678661
neonatal meningoencephalitis caused by bacillus cereus.the classic organisms associated with central nervous system infection in the neonate are herpes simplex, listeria monocytogenes, escherichia coli, and streptococcus agalactiae; we describe an unusual case of neonatal meningoencephalitis caused by bacillus cereus.200818679155
decontamination of knives used in the meat industry: effect of different water temperature and treatment time combinations on the reduction of bacterial numbers on knife surfaces.previous regulations in australia and internationally required that knives used during the slaughter and dressing of carcasses be sanitized by brief submersion in water at 82 degrees c. many current international regulations allow science-based equivalent alternative procedures to be used. however, limited time-temperature data are available on the response of bacteria to hot-water treatment on knives. the present study was undertaken to determine the effect of combinations of time and temperatu ...200818680930
metabiotic effects of fusarium spp. on escherichia coli o157:h7 and listeria monocytogenes on raw portioned tomatoes.the metabiotic effects of fusarium proliferatum, f. avenaceum, and f. oxysporum on escherichia coli o157:h7 and listeria monocytogenes in fresh tomatoes were investigated. tomatoes were preinoculated with the molds and incubated at 15 degrees c for 7 days; then they were inoculated separately with the pathogens, packaged in air and modified atmosphere (5% o2, 30% co2, and 65% n2), and stored at 4, 8, and 12 degrees c for 9 days. the cell loads of pathogens and lactic acid bacteria and the ph wer ...200818680934
adhesion to and viability of listeria monocytogenes on food contact surfaces.listeria monocytogenes is an important pathogen responsible for major outbreaks associated with food products. adhesion to surfaces leads to significant modifications in cell physiology. the aim of this work was to determine the adhesion ability of 10 isolates of l. monocytogenes to eight materials commonly used in kitchens and to evaluate the viability of the adhered cells. the materials assayed were stainless steel 304, marble, granite, glass, polypropylene from a bowl and from a cutting board ...200818680936
inhibition of listeria monocytogenes growth in cured ready-to-eat meat products by use of sodium benzoate and sodium diacetate.the effect of sodium benzoate (0.08 to 0.25%) in combination with different concentrations of sodium diacetate (0.05 to 0.15%) and nacli (0.8 to 2%) and different finished product moisture (55 to 75%) on the growth of listeria monocytogenes in ready-to-eat meat products was evaluated using a central composite design over 18 weeks of storage at 4 degrees c. the effects of these factors on time to growth were analyzed using a time-to-failure regression method. all main effects were significant exc ...200818680937
antibacterial effects of long-chain polyphosphates on selected spoilage and pathogenic bacteria.the antimicrobial activities of four long-chain food-grade polyphosphates were studied at concentrations allowed in the food industry (<5,000 ppm) in defined basal media by determining the inhibition of growth of three gram-negative and four gram-positive spoilage and pathogenic bacteria. both generation time and lag phase of escherichia coli k-12, e. coli o157: h7, and salmonella typhimurium were increased with all of the polyphosphates tested. bacillus subtilis and staphylococcus aureus were m ...200818680939
role of sigma b factor in the alkaline tolerance response of listeria monocytogenes 10403s and cross-protection against subsequent ethanol and osmotic stress.many of the considerable abilities of listeria monocytogenes to persist and grow in a wide range of adverse environmental conditions are thought to be at least partly under the control of the alternative sigma factor (sigmab), encoded by the sigb gene. however, little is known about the role of this master regulon in the impressive ability of listeria to persist and grow under conditions of alkaline ph. in this study, northern blot analysis of parent listeria mrna revealed that alkali adaptation ...200818680951
funcat functional inference with belief propagation and feature integration.pairwise comparison of sequence data is intensively used for automated functional protein annotation, while graphical models emerge as promising candidates for an integration of various heterogeneous features. we designed a model, termed hrmn that integrates different genomic features and implemented a variant of belief propagation for functional annotation transfer. hrmn allows the assignment of multiple functional categories while avoiding common problems in annotation transfer from heterogene ...200818684672
probiotics protect mice against experimental infections.our group has concerned itself with the study of the effect of probiotics on the resistance to infections using experimental models. here, we will focus on evidence that the ufv-h2b20 strain of lactobacillus delbrueckii var. bulgaricus may be considered a probiotic and has protective effects on mice against a variety of bacterial infections.200818685501
effectiveness of chitosan-coated plastic films incorporating antimicrobials in inhibition of listeria monocytogenes on cold-smoked salmon.the objective of this study was to evaluate the efficacy of chitosan-coated plastic films incorporating five generally recognized as safe (gras) antimicrobials (nisin, sodium lactate (sl), sodium diacetate (sd), potassium sorbate (ps) and sodium benzoate (sb)) against listeria monocytogenes on cold-smoked salmon. salmon samples were surface-inoculated with a five-strain cocktail of l. monocytogenes and packaged in chitosan-coated plastic films containing 500 iu/cm(2) of nisin, 9 mg/cm(2) of sl, ...200818707789
the profilin:actin complex localizes to sites of dynamic actin polymerization at the leading edge of migrating cells and pathogen-induced actin tails.a unique set of affinity-purified anti-profilin and anti-actin antibodies generated against a covalently coupled version of the profilin:actin complex was used to assess the distribution of profilin and non-filamentous actin in mouse melanoma cells. in agreement with the profilin:actin complex being the principal source of actin for filament formation, we observed extensive co-distribution of both antibody preparations with vasodilator-stimulated phosphoprotein (vasp) and the p34 subunit of the ...200818707793
functional whole-colony screening method to identify antimicrobial peptides.a high throughput method for screening cdna libraries has been developed to identify putative antimicrobial peptides (amps). it is based on a rapid dye inclusion assay for assessing antagonism of bacterial viability. colonies are grown on a membrane on a permissive medium until full colony size is reached. the membrane, supporting the array of colonies, is transferred onto an inductive medium containing a vital dye. upon expression of any antagonizing peptides, the cell membrane becomes compromi ...200818708097
listeria monocytogenes infection in pregnant guinea pigs is associated with maternal liver necrosis, a decrease in maternal serum tnf-alpha concentrations, and an increase in placental apoptosis.stillbirths and spontaneous abortions can result when pregnant women are exposed to the food borne pathogen, listeria monocytogenes. fetuses and neonates account for one-third of the 2500 cases annually. the objectives were to determine the dose dependent trends of immunological and pathological effects in pregnant guinea pigs after infection with l. monocytogenes. timed pregnant guinea pigs were treated on gestation day (gd) 35 with doses of 10(4) to 10(8) colony forming units (cfus) and sacrif ...200818708136
colorimetric assay for biofilms in wet processing conditions.controlling bacterial biofilms is necessary for food safety and industrial processing in clean room environments. our goal was to develop a method to quantitatively measure biofilm produced by pathogens under wet poultry production and processing conditions. stainless steel and glass coupons were incubated in aqueous media containing reduced nutrients and exposed to listeria monocytogenes under static temperature and humidity conditions. samples were measured separately by biofilm assay and viab ...200818712536
differential regulation of listeria monocytogenes internalin and internalin-like genes by sigmab and prfa as revealed by subgenomic microarray analyses.the listeria monocytogenes genome contains more than 20 genes that encode cell surface-associated internalins. to determine the contributions of the alternative sigma factor sigma(b) and the virulence gene regulator prfa to internalin gene expression, a subgenomic microarray was designed to contain two probes for each of 24 internalin-like genes identified in the l. monocytogenes 10403s genome. competitive microarray hybridization was performed on rna extracted from (i) the 10403s parent strain ...200818713061
impact of compounding error on strategies for subtyping pathogenic bacteria.comparative-omics will identify a multitude of markers that can be used for intraspecific discrimination between strains of bacteria. it seems intuitive that with this plethora of markers we can construct higher resolution subtyping assays using discrete markers to define strain "barcodes." unfortunately, with each new marker added to an assay, overall assay robustness declines because errors are compounded exponentially. for example, the difference in accuracy of strain classification for an as ...200818713065
the growth limits of a large number of listeria monocytogenes strains at combinations of stresses show serotype--and niche-specific traits.the aim of this study was to associate the growth limits of listeria monocytogenes during exposure to combined stresses with specific serotypes or origins of isolation, and identify potential genetic markers.200818713284
il-17a produced by gammadelta t cells plays a critical role in innate immunity against listeria monocytogenes infection in the liver.il-17a is originally identified as a proinflammatory cytokine that induces neutrophils. although il-17a production by cd4(+) th17 t cells is well documented, it is not clear whether il-17a is produced and participates in the innate immune response against infections. in the present report, we demonstrate that il-17a is expressed in the liver of mice infected with listeria monocytogenes from an early stage of infection. il-17a is important in protective immunity at an early stage of listerial inf ...200818714018
tio2 nanowire bundle microelectrode based impedance immunosensor for rapid and sensitive detection of listeria monocytogenes.a novel tio 2 nanowire bundle microelectrode based immunosensor was demonstrated as a more sensitive, specific, and rapid technology for detection of listeria monocytogenes. tio 2 nanowire bundle was prepared through a hydrothermal reaction of alkali with tio 2 powder and connected to gold microelectrodes with mask welding. monoclonal antibodies were immobilized on the surface of a tio 2 nanowire bundle to specifically capture l. monocytogenes. impedance change caused by the nanowire-antibody-ba ...200818715043
inhibition of vancomycin and high-level aminoglycoside-resistant enterococci strains and listeria monocytogenes by bacteriocin-like substance produced by enterococcus faecium e86.three hundred and thirty nine lactic bacteria strains isolated from food samples were screened for antimicrobial activity. only one strain isolated from meat pie and identified as enterococcus faecium produced a bacteriocin-like inhibitory substance (blis) showing activity against enterococcus, leuconostoc, lactobacillus, listeria, corynebacterium and staphylococcus aureus. the blis produced was resistant to acid and alkali treatment and 121 masculinec for 15 min. the addition of blis in bhi con ...200818716832
assessment of the stability of cell-surface components of microorganisms by maldi-tof-ms following preservation on lenticule discs.strains representing the species campylobacter coli, escherichia coli, listeria monocytogenes, pseudomonas aeruginosa, salmonella enterica, and staphylococcus aureus were randomly selected to assess the consistency of cells preserved on lenticule discs to those archived in traditional freeze-dried ampoules. each matched pair was cultured using identical conditions and analysed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (ms) to profile the surface-associated m ...200818717884
[the regulation of sigmab activity and its role in some gram-positive food-borne pathogens--a review].the alternative sigma factor sigmab modulates the stress response of several gram-positive bacteria. not only does sigmab play a prominent role in sporulation in the gram-positive model organism bacillus subtilis, but it also contributes both directly and indirectly to bacterial virulence in the food-borne human pathogens bacillus cereus, listeria monocytogenes and staphylococcus aureus. as sigmab has been shown to regulate expression of both virulence and virulence-associated genes, it indicate ...200818720853
inactivation kinetics of inoculated escherichia coli o157:h7, listeria monocytogenes and salmonella poona on whole cantaloupe by chlorine dioxide gas.the objectives of this study were to examine inactivation kinetics of inoculated escherichia coli o157:h7, listeria monocytogenes and salmonella poona inoculated onto whole cantaloupe and treated with clo(2) gas at different concentrations (0.5, 1.0, 1.5, 3.0 and 5.0 mg l(-1)) for different times (0, 2.0, 4.0, 6.0, 8.0 and 10.0 min). the effect of clo(2) gas on the quality and shelf life of whole cantaloupe was also evaluated during storage at 22 degrees c for 12 days. a 100 microl inoculation o ...200818721673
effect of combining nisin and/or lysozyme with in-package pasteurization for control of listeria monocytogenes in ready-to-eat turkey bologna during refrigerated storage.this study investigated the efficacy of in-package pasteurization combined with pre-surface application of nisin and/or lysozyme to reduce and prevent the subsequent recovery and growth of listeria monocytogenes during refrigerated storage on the surface of low-fat turkey bologna. sterile bologna samples were treated with solutions of nisin (2 mg/ml=5000 au/ml), lysozyme (10 mg/ml=80 au/ml) and a mixture of nisin and lysozyme (2 mg nisin+10mg lysozyme/ml) before in-package pasteurization at 65 d ...200818721674
effect of poultry decontaminants concentration on growth kinetics for pathogenic and spoilage bacteria.various chemical compounds are currently under review for final approval as poultry decontaminants in the european union (eu). concentration is among the factors considered by the eu authorities in the evaluation of these treatments. the aim of this research was to compare the growth parameters for pathogenic and spoilage bacteria in presence of high and low concentrations of poultry decontaminants to assess whether such treatments could involve a potential sanitary risk for consumers. growth cu ...200818721678
listeria monocytogenes sclerokeratitis: a case report and literature review.to report a case of listeria monocytogenes sclerokeratitis and to review the literature.200818724160
microbial quality of raw aquacultured fish fillets procured from internet and local retail markets.the microbial quality of raw fillets of aquacultured catfish, salmon, tilapia, and trout was evaluated. a total of 272 fillets from nine local and nine internet retail markets were tested. mean values were 5.7 log cfu/g for total aerobic mesophiles, 6.3 log cfu/g for psychrotrophs, and 1.9 log most probable number (mpn) per gram for coliforms. differences in these microbial levels between the two kinds of markets and among the four types of fish were not significant (p > 0.05), except that inter ...200818724746
survival of listeria monocytogenes strains in a dry sausage model.the survival of five inoculated listeria monocytogenes strains (dcs 31, dcs 184, at3e, ht4e, and hr5e) was studied in dry fermented sausages prepared using two different starter cultures (starter a and b) with or without a protective lactobacillus plantarum dden 2205 strain. l. monocytogenes was detected throughout ripening in every sausage sample in which the l. plantarum dden 2205 strain had not been used. the use of either starter a, with a high concentration of protective culture, or starter ...200818724747
comparison of the stress response of listeria monocytogenes strains with sprout colonization.twenty-nine strains of the foodborne pathogen listeria monocytogenes were tested for their ability to colonize alfalfa, radish, and broccoli sprouts and their capacity to withstand acid and oxidative stress, two stresses common to the sprouting environment. wide variation in the ability of different strains to colonize alfalfa sprouts were confirmed, but the variations among radish and broccoli sprouts were not as large. with a few exceptions, strains that were poor colonizers of alfalfa tended ...200818724748
60-day aging requirement does not ensure safety of surface-mold-ripened soft cheeses manufactured from raw or pasteurized milk when listeria monocytogenes is introduced as a postprocessing contaminant.because of renewed interest in specialty cheeses, artisan and farmstead producers are manufacturing surface-mold-ripened soft cheeses from raw milk, using the 60-day holding standard (21 cfr 133.182) to achieve safety. this study compared the growth potential of listeria monocytogenes on cheeses manufactured from raw or pasteurized milk and held for > 60 days at 4 degrees c. final cheeses were within federal standards of identity for soft ripened cheese, with low moisture targets to facilitate t ...200818724749
low incidence of foodborne pathogens of concern in raw milk utilized for farmstead cheese production.overall milk quality and prevalence of four target pathogens in raw milk destined for farmstead cheesemaking was examined. raw milk samples were collected weekly from june to september 2006 from 11 farmstead cheese operations manufacturing raw milk cheese from cow's, goat's, and sheep's milk. samples were screened for listeria monocytogenes, staphylococcus aureus, salmonella, and escherichia coli o157:h7 both quantitatively (direct plating) and qualitatively (pcr). overall, 96.8% of samples had ...200818724751
effects of high pressure, subzero temperature, and ph on survival of listeria monocytogenes in buffer and smoked salmon.high pressure processing is a novel food preservation technology, applied for over 15 years in the food industry to inactivate spoilage and pathogenic microorganisms. many studies have shown the differential resistance of bacterial cells to high pressure. listeria monocytogenes is a bacterium able to grow at refrigerated temperature and to survive for a long time in minimally processed foods such as raw smoked fish. the freezing process does not cause significant decline of l. monocytogenes. the ...200818724755
cold atmospheric plasma disinfection of cut fruit surfaces contaminated with migrating microorganisms.the efficacy of cold atmospheric gas plasmas against escherichia coli type 1, saccharomyces cerevisiae, gluconobacter liquefaciens, and listeria monocytogenes scott a was examined on inoculated membrane filters and inoculated fruit surfaces. inoculated samples were exposed to a cold atmospheric plasma plume generated by an ac voltage of 8 kv at 30 khz. the cold atmospheric plasma used in this study was very efficient in reducing the microbial load on the surfaces of filter membranes. however, it ...200818724756
antimicrobial activity of extracts of edible wild and cultivated mushrooms against foodborne bacterial strains.the antimicrobial activity of aqueous, methanol, hexane, and ethyl acetate extracts from edible wild and cultivated mushrooms against nine foodborne pathogenic bacterial strains (escherichia coli o157:h7, salmonella enteritidis, shigella sonnei, vibrio parahaemolyticus, yersinia enterocolitica, bacillus cereus, clostridium perfringens, listeria monocytogenes, and staphylococcus aureus) was screened with a disk diffusion assay. twenty-nine of the 48 species tested had antimicrobial activity. meth ...200818724768
listeria monocytogenes--which of your patients is not at risk?listeria monocytogenes is an environmental bacterium that is capable of causing infection (known as listeriosis) in vulnerable people who generally acquire the organism following the ingestion of contaminated foods. pregnant women are a particular risk group, as listeriosis in pregnancy is associated with an increased risk of spontaneous abortion, stillbirth, neonatal septicaemia and meningitis. the immunocompromised, and people over the age of 65 to 70 are also at increased risk of listeriosis. ...200818727264
genetic dissection of host resistance to mycobacterium tuberculosis: the sst1 locus and the ipr1 gene.genetic variation of the host significantly contributes to dramatic differences in the outcomes of natural infection with virulent mycobacterium tuberculosis (mtb) in humans, as well as in experimental animal models. host resistance to tuberculosis is a complex multifactorial genetic trait in which many genetic polymorphisms contribute to the phenotype, while their individual contributions are influenced by gene-gene and gene-environment interactions. the most epidemiologically significant form ...200818727490
mage-b vaccine delivered by recombinant listeria monocytogenes is highly effective against breast cancer metastases.new therapies are needed that target breast cancer metastases. in previous studies, we have shown that vaccination with pcdna3.1-mage-b dna vaccine is effective against breast cancer metastases. in the study presented here, we have further enhanced the efficacy of mage-b vaccination through the improved delivery of the vaccine using recombinant listeria monocytogenes (lm). three overlapping fragments of mage-b as well as the complete protein-encoding region of mage-b have been expressed as a fus ...200818728665
horizontal gene transfers link a human mrsa pathogen to contagious bovine mastitis bacteria.acquisition of virulence factors and antibiotic resistance by many clinically important bacteria can be traced to horizontal gene transfer (hgt) between related or evolutionarily distant microflora. comparative genomic analysis has become an important tool for identifying hgt dna in emerging pathogens. we have adapted the multi-genome alignment tool evoprinter to facilitate discovery of hgt dna sequences within bacterial genomes and within their mobile genetic elements.200818728754
animal models of listeria infection.listeria monocytogenes is an intracellular foodborne pathogen that causes listeriosis, an infection characterized by gastroenteritis, meningitis, encephalitis, and maternofetal infections in humans. l. monocytogenes enters the host via contaminated foods, invades the small intestine, translocates to mesenteric lymph nodes, and spreads to the liver, spleen, brain and, in pregnant women, the fetoplacental unit. many pathogenicity tests for studying l. monocytogenes have been developed, including t ...200818729060
persistent fever, mediastinal mass in a 5-year-old boy. 200818751568
bacterial meningitis and sigmoid diverticulitis caused by listeria monocytogenes. 200818751639
decreasing listeriosis mortality in the united states, 1990-2005.listeria monocytogenes is among the most virulent foodborne pathogens, with 20% of clinical infections resulting in death. to explore listeriosis-associated mortality in the united states and to evaluate prevention efforts, we reviewed vital records over a 16-year period to assess demographic, temporal, and seasonal trends.200818752441
different contamination patterns of lineage i and ii strains of listeria monocytogenes in a spanish broiler abattoir.the purpose of this study was to determine whether genetically similar or diverse strains of listeria monocytogenes colonize the environment and carcasses in a single spanish broiler abattoir over time. the study was composed of 5 surveys over a 1.5-yr period and included the monitoring of cleaning and disinfection procedures. overall, a total of 212 samples were tested for the presence of l. monocytogenes, and 31% of the samples were found to be positive. listeria monocytogenes was isolated fro ...200818753457
non-classical use of clathrin during bacterial infections.how invasive bacteria exploit mammalian host cell components to induce their entry into cells has received a lot of attention in the last two decades. model organisms have emerged and helped understanding the various mechanisms that are used. among those, listeria monocytogenes is one of the most documented organisms. it enters into cells via two bacterial proteins, internalin (also called inla) and inlb, which interact with cell surface receptors, e-cadherin and the hepatocyte growth factor rec ...200818755008
impact of bacterial stress and biofilm-forming ability on transfer of surface-dried listeria monocytogenes during slicing of delicatessen meats.listeria monocytogenes contamination of delicatessen slicer blades can lead to cross-contamination of luncheon meats. a cocktail of 3 strong or 3 weak biofilm-forming strains of l. monocytogenes suspended in turkey slurry was used to inoculate stainless steel delicatessen slicer blades at a level of 6 log cfu/blade. the cocktails were used with or without injury (cold-shocked at 4 degrees c for 2 h, or chlorine-injured at 100 ppm for 1 min). inoculated blades were held at 22 degrees c/78+/-2% re ...200818755520
effects of pulsed electric fields on pathogenic microorganisms of major concern in fluid foods: a review.pathogenic microorganisms such as escherichia coli o157:h7, salmonella spp., listeria monocytogenes, bacillus cereus, staphylococcus aureus, yersinia enterocolitica, and campylobacter jejuni have been implicated in foodborne diseases and outbreaks worldwide. these bacteria have been associated with the consumption of fresh fruit juices, milk, and dairy products, which are foodstuff, highly demanded by consumers in retails and supermarkets. nowadays, consumers require high quality, fresh-like, an ...200818756397
characterization of linear forms of the circular enterocin as-48 obtained by limited proteolysis.as-48 is a 70-residue circular peptide from enterococcus faecalis with a broad antibacterial activity. here, we produced by limited proteolysis a protein species carrying a single nicking and fragments of 55 and 38 residues. nicked as-48 showed a lower helicity by far-ultraviolet circular dichroism and a reduced stability to thermal denaturation, but it was active against the sensitive bacteria assayed. the fragments also partly retained the biological activity of the intact protein. these resul ...200818760277
bacterial entry to the splenic white pulp initiates antigen presentation to cd8+ t cells.the spleen plays an important role in host-protective responses to bacteria. however, the cellular dynamics that lead to pathogen-specific immunity remain poorly understood. here we examined listeria monocytogenes (lm) infection in the mouse spleen via in situ fluorescence microscopy. we found that the redistribution of lm from the marginal zone (mz) to the periarteriolar lymphoid sheath (pals) was inhibited by pertussis toxin and required the presence of cd11c(+) cells. as early as 9 hr after i ...200818760639
update and actual trends on bacterial infections following liver transplantation.recent advances in effective antimicrobial prophylactic strategies have led to a decline in the incidence of opportunistic infections in liver transplant recipients. however, morbidity and mortality due to infectious diseases remain as major problems. bacterial infections occurring early after transplant are mainly related to the technical aspects of the procedure. by contrast, after the first postoperative days and beyond, the nature and variety of infectious complications change. opportunistic ...200818763277
central nervous system infection with listeria monocytogenes.the foodborne pathogen listeria monocytogenes has a particular tropism for the central nervous system and can produce infection in the meninges and brain substance. well-recognized clinical syndromes include meningitis, brain abscess, rhombencephalitis, and spinal cord abscess; simultaneous infection of the meninges and brain is common. although it is an uncommon cause of infection in the population at large, l. monocytogenes is an important cause of central nervous system infection in those wit ...200818765103
analysis of the isoprenoid biosynthesis pathways in listeria monocytogenes reveals a role for the alternative 2-c-methyl-d-erythritol 4-phosphate pathway in murine infection.most bacteria synthesize isoprenoids through one of two essential pathways which provide the basic building block, isopentyl diphosphate (ipp): either the classical mevalonate pathway or the alternative non-mevalonate 2-c-methyl-d-erythritol 4-phosphate (mep) pathway. however, postgenomic analyses of the listeria monocytogenes genome revealed that this pathogen possesses the genetic capacity to produce the complete set of enzymes involved in both pathways. the nonpathogenic species listeria inno ...200818765739
gammadeltat cell-mediated regulation of chemokine producing macrophages during listeria monocytogenes infection-induced inflammation.infection of gammadeltat cell-deficient (tcrdelta-/-) mice with the intracellular bacterium listeria monocytogenes (lm) results in an exacerbated inflammatory response characterized by the accumulation of activated macrophages and necrotic liver lesions. here we investigated whether changes in chemokine production by lm-elicited macrophages contribute to this abnormal inflammatory response. in response to lm infection, activated macrophages accumulate in the primary sites of infection in tcrdelt ...200818767021
promises and challenges for the development of listeria monocytogenes-based immunotherapies.active immunotherapy has shown great promise in preclinical models for the treatment of infectious and malignant disease. yet, these promising results have not translated into approved therapies. one of the major deficits of active immunotherapies tested to date in advanced clinical studies has been their inability to stimulate both arms of the immune system appropriately. the interest in using recombinant bacteria as vaccine vectors for active immunotherapy derives in part from their ability to ...200818767955
the protein tyrosine phosphatase ptpn4/ptp-meg1, an enzyme capable of dephosphorylating the tcr itams and regulating nf-kappab, is dispensable for t cell development and/or t cell effector functions.t cell receptor signaling processes are controlled by the integrated actions of families of protein tyrosine kinases (ptks) and protein tyrosine phosphatases (ptpases). several distinct cytosolic protein tyrosine phosphatases have been described that are able to negatively regulate tcr signaling pathways, including shp-1, shp-2, ptph1, and pep. using ptpase substrate-trapping mutants and wild type enzymes, we determined that ptpn4/ptp-meg1, a ptph1-family member, could complex and dephosphorylat ...200818614237
genetic variation of listeria monocytogenes isolates from domestic and imported foods in japan.phylogenetic analyses were carried out on a total of 118 listeria monocytogenes isolates from foods or food processing environments, and 7 isolates from listeriosis patients in japan to evaluate the genetic variation in the pathogen in this country. isolates of serotypes 1/2a, 1/2b and 4b were mainly examined to assess the risk of exposure of humans to l. monocytogenes from foods in japan. the nucleotide sequences of the part of the iap gene that contains the region encoding the threonine-aspara ...200818614253
children with bacterial meningitis presenting to the emergency department during the pneumococcal conjugate vaccine era.the epidemiology of bacterial meningitis in children in the era of widespread heptavalent conjugate pneumococcal vaccination (pcv7) is unknown.200818616437
echinacea-induced macrophage activation.public interest in echinacea is growing rapidly. unfortunately, there is little scientific evidence to support claims of efficacy of this widely used botanical, and little information about potential mechanism of action. this study examines the ability of echinacea to upregulate macrophage function and begins to elucidate the mechanism of echinacea-induced macrophage activation. murine peritoneal macrophages were cultured with e. purpurea extracts enriched for plant polysaccharide (ep). elisa wa ...200818618312
listeria monocytogenes septicaemia and concurrent clostridial infection in an adult alpaca (lama pacos).a 10-year-old alpaca with a history of anorexia, weight loss and diarrhoea was humanely destroyed and shown to have a multifocal necrotizing hepatitis, splenitis and colitis, as well as an ulcerative to diphtheroid ileitis. immunohistochemical examination revealed listeria monocytogenes antigen in the liver and ileum. in addition, l. monocytogenes and listeria sp.-specific gene fragments were detected by the polymerase chain reaction. l. monocytogenes was isolated from liver and small intestine ...200818619608
modulation of stress and virulence in listeria monocytogenes.listeria monocytogenes can respond rapidly to changing environmental conditions, as illustrated by its ability to transition from a saprophyte to an orally transmitted facultative intracellular pathogen. differential associations between various alternative sigma factors and a core rna polymerase provide a transcriptional mechanism for regulating bacterial gene expression that is crucial for survival in rapidly changing conditions. alternative sigma factors are key components of complex l. monoc ...200818619843
bacteriocin-producing lactobacillus strains isolated from poto poto, a congolese fermented maize product, and genetic fingerprinting of their plantaricin operons.thirty one bacteriocin-producing lactobacillus isolates were identified among 135 lactobacilli isolated from the congolese fermented maize product poto poto, during the preparation and from the finished product. using species-specific pcr and 16s rrna gene sequencing, 28 and 3 isolates were identified as l. plantarum and l. fermentum, respectively. cluster analysis of rapd-pcr fingerprints revealed two main groups (g1 and g2) plus the l. fermentum isolate c4-13. group g1 contained 23 isolates wi ...200818620772
viability of multi-strain mixtures of listeria monocytogenes, salmonella typhimurium, or escherichia coli o157:h7 inoculated into the batter or onto the surface of a soudjouk-style fermented semi-dry sausage.the fate of listeria monocytogenes, salmonella typhimurium, or escherichia coli o157:h7 were separately monitored both in and on soudjouk. fermentation and drying alone reduced numbers of l. monocytogenes by 0.07 and 0.74 log(10)cfu/g for sausages fermented to ph 5.3 and 4.8, respectively, whereas numbers of s. typhimurium and e. coli o157:h7 were reduced by 1.52 and 3.51 log(10)cfu/g and 0.03 and 1.11 log(10)cfu/g, respectively. when sausages fermented to ph 5.3 or 4.8 were stored at 4, 10, or ...200818620971
the response of hek293 cells transfected with bovine tlr2 to established pathogen-associated molecular patterns and to bacteria causing mastitis in cattle.toll-like receptors (tlrs) are key sensors of pathogen-associated molecular patterns (pamps). their role in immunity is difficult to examine in species of veterinary interest, due to restricted access to the knockout technology and tlr-specific antibodies. an alternative approach is to generate cell lines transfected with various tlrs and to examine the recognition of pamps or relevant bacteria. in this report, we examined whether recognition of various pamps and mastitis-causing bacteria is ach ...200818621422
identification of a sigma b-dependent small noncoding rna in listeria monocytogenes.in listeria monocytogenes, the alternative sigma factor sigma(b) plays important roles in stress tolerance and virulence. here, we present the identification of sbra, a novel small noncoding rna that is produced in a sigma(b)-dependent manner. this finding adds the sigma(b) regulon to the growing list of stress-induced regulatory circuits that include small noncoding rnas.200818621897
successive post-translational modifications of e-cadherin are required for inla-mediated internalization of listeria monocytogenes.listeria monocytogenes surface proteins internalin (inl)a and inlb interact with the junctional protein e-cadherin and the hepatocyte growth factor (hgf) receptor met, respectively, on the surface of epithelial cells to mediate bacterial entry. here we show that inla triggers two successive e-cadherin post-translational modifications, i.e. the src-mediated tyrosine phosphorylation of e-cadherin followed by its ubiquitination by the ubiquitin-ligase hakai. e-cadherin ubiquitination induces the re ...200818624796
bioprotective leuconostoc strains against listeria monocytogenes in fresh fruits and vegetables.ten leuconostoc mesenteroides and one ln. citreum strains isolated from fresh fruit and vegetables were tested for their antagonistic capacity against listeria monocytogenes. genetic differences among strains were analyzed by random amplified polymorphic dna (rapd). all the isolates clustered together and differed from the type strain ln. mesenteroides atcc 8293 as well as from ln. fallax and ln. citreum. organic acids, hydrogen peroxide and bacteriocins were detected as main inhibition mechanis ...200818625532
carbon metabolism of listeria monocytogenes growing inside macrophages.the intracellular metabolism of listeria monocytogenes was studied by (13)c-isotopologue profiling using murine j774a.1 macrophages as host cells. six hours after infection, bacteria were separated from the macrophages and hydrolyzed. amino acids were converted into tert-butyl-dimethylsilyl derivatives and subjected to gas chromatography/mass spectrometry. when the macrophages were supplied with [u-(13)c(6)]glucose prior to infection, but not during infection, label was detected only in ala, asp ...200818627458
circumvention of regulatory cd4(+) t cell activity during cross-priming strongly enhances t cell-mediated immunity.immunization with purified antigens is a safe and practical vaccination strategy but is generally unable to induce sustained cd8(+) t cell-mediated protection against intracellular pathogens. most efforts to improve the cd8(+) t cell immunogenicity of these vaccines have focused on co-administration of adjuvant to support cross-presentation and dendritic cell maturation. in addition, it has been shown that cd4(+) t cell help during the priming phase contributes to the generation of protective cd ...200818465771
control of listeria monocytogenes on vacuum-packaged frankfurters sprayed with lactic acid alone or in combination with sodium lauryl sulfate.u.s. regulations require that processors employ lethal or inhibitory antimicrobial alternatives in production of ready-to-eat meat and poultry products that support growth of listeria monocytogenes and may be exposed to the processing environment after a lethality treatment. in this study, lactic acid (la; 5%, vol/vol) and sodium lauryl sulfate (sls; 0.5%, wt/vol) were evaluated individually or as a mixture (lasls) for control of l. monocytogenes on frankfurters. frankfurters were inoculated wit ...200818468026
monitoring hygiene on- and at-line is critical for controlling listeria monocytogenes during produce processing.the prevalence of listeria monocytogenes in different types of produce and on processing plant environments was investigated over a 4-year period in a large produce processing plant in poland. prevalence of l. monocytogenes was 46% in frozen vegetables and 41.3% in swab samples taken from the plant environment. survival studies using artificial inocula demonstrated that the number of listeria in frozen produce stored for 100 days did not significantly decrease in relation to the initial contamin ...200818468027
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