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[differentiantion of listeria monocytogenes strains isolated in the far east and european part of russia on the basis of polymorphism of genes encoding invasion factors].forty listeria monocytogenes isolates obtained in european and far east regions of russia were differentiated on the basis of polymorphism of 5 markergenes. total length of concatemers obtained after sequencing of internal fragments of genes inla, inlb, inlc, inle and prs was 3029 b.p. comparative analysis of concatemers' sequences revealed 237 variable nucleotides. totally, 25 sequence types were revealed, and isolates from european and far east regions belonged to different types. on the dendr ...200819186537
[growth media for isolation, accumulation, and identification of listeria in laboratory diagnostics of mix-infections in women with obstetric-gynecological pathology].isolation of lysteria monocytogenes from clinical specimens in obstetric-gynecological pathology is often difficult owing to the presence of the mixed microbial flora. results of study of new russian growth media for isolation of listeria for microbiological diagnostics of listeriosis in pregnancy are presented. they show diagnostic efficacy of the developed media for laboratory diagnostics of mix-infections in women with obstetric-gynecological pathology.200819186555
antimicrobial activity of organically modified nano-clays.antimicrobial activity of three kinds of commercially available montmorillonite nano-clays including a naturally occurring one (cloisite na+) and two organically modified ones (cloisite 20a and cloisite 30b) against four representative pathogenic bacteria (two gram-positive ones such as staphylococcus aureus and listeria monocytogenes, and two gram-negative ones such as salmonella typhimurium and e. coli o157:h7) was investigated. antimicrobial activity was found to be dependent on the type of n ...200819198311
characterization and partial purification of entomocin 110, a newly identified bacteriocin from bacillus thuringiensis subsp. entomocidus hd110.a new bacteriocin produced by bacillus thuringiensis subsp. entomocidus was identified. the antibacterial activity termed entomocin 110 was produced starting at mid-logarithmic growth phase, reaching its maximum at the early and during stationary phase. the bacteriocin obtained from culture supernatant was inhibitory to several gram-positive bacteria including listeria monocytogenes, paenibacillus larvae and other bacillus species. entomocin 110 was shown to be heat stable and resistant to ph va ...200819216106
multiplex-pcr serotyping of listeria monocytogenes isolated from human clinical specimens.the genus listeria is composed of six species of which listeria monocytogenes is considered the single pathogenic species that causes listeriosis in humans. of the 13 serovars of l. monocytogenes, 1/2a, 1/2b and 4b are responsible for the majority of clinical cases. the aim of this work was to detect l. monocytogenes in the cerebrospinal fluid sample of premature newborns and to characterize this sample using biotyping, serotyping and molecular typing. the results indicated the presence of l. mo ...200819148426
[rapid detection of vibrio parahaemolyticus by taqman-based real-time pcr assay targeting the toxr gene].we designed a pair of specific primers and a taqman fluorescent probe targeting the toxr gene of vibrio parahaemolyticus (vp). after optimizing the conditions, the specialty, sensitivity and reproducibility of the detection method were evaluated. results: (1) the developed real-time pcr assay protocol detected only vp and was not affected by other normal food pathogens such as staphylococcus aureus, salmonela, listeria monocytogenes. (2) the limit of detection was 25 copies of toxr gene in the d ...200819149202
effect of whey protein coating on quality attributes of low-fat, aerobically packaged sausage during refrigerated storage.whey protein-based edible coating was used to reduce oxidative degradation and microbial growth of low-fat sausages (lfss) stored at 4 degrees c for 8 wk, under aerobic package. whey protein coating reduced (p<0.05) thiobarbituric acid-reactive substances (tbars) and peroxide value (pv) formation compared to control sausages. the percent inhibition of tbars and pv for whey protein-coated sausages, compared to the control, was 31.3% and 27.1%, respectively. the ability of the whey protein coating ...200819241536
modeling surface transfer of listeria monocytogenes on salami during slicing.listeria monocytogenes has been implicated in several listeriosis outbreaks linked to the consump tion of presliced ready-to-eat (rte) deli meats, which has drawn considerable attention in regard to possible cross-contamination during slicing operation at retail and food service environments. salami with 15% fat (a moderate l fat content deli item) was used to investigate the transfer of l. monocytogenes between a meat slicer and salami slices and to understand its impact on food safety. a 6-str ...200819241551
effect of electrolyzed water for reduction of foodborne pathogens on lettuce and spinach.the ability of electrolyzed water (ew) to inactivate foodborne pathogens on the surfaces of lettuce and spinach was investigated. lettuce and spinach leaves were inoculated with a cocktail of 3 strains each of escherichia col o157:h7, salmnonella typhimurium, and listeria monocytogenes and treated with acidic electrolyzed water (ac-ew), alkaline electrolyzed water (ak-ew), alkaline electrolyzed water followed by acidic electrolyzed water (sequential treatment, ak-ew + ac-ew), deionized water fol ...200819241556
microbial assessment in school foodservices and recommendations for food safety improvement.this study evaluated microbial food safety in school foodservices. five school foodservices were randomly selected, and samples from water, cooking utensils, tableware, foodservice surroundings, and linen were collected in summer and winter (n=420). tap and drinking water samples were collected, samples of food contact surfaces were collected by swab-kit, and samples for foodservice workers' hands and gloves were prepared by glove juice method. aerobic plate count (apc) and coliform bacterial po ...200819241563
coliforms and prevalence of escherichia coli and foodborne pathogens on minimally processed spinach in two packing plants.minimally processed spinach has been recently associated with outbreaks of foodborne illnesses. this study investigated the effect of commercial minimal processing of spinach on the coliform and escherichia coli counts and the prevalence of e. coli o157:h7, salmonella, shigella spp., and listeria monocytogenes on two types of spinach before and after minimal processing. a total of 1,356 spinach samples (baby spinach, n = 574; savoy spinach, n = 782) were collected daily in two processing plants ...200819244890
inactivation of listeria monocytogenes in raw fruits by enterocin as-48.the purpose of this study was to determine the effect of enterocin as-48 on listeria monocytogenes cect 4032 in fruits and fruit juice. fruits were contaminated with a l. monocytogenes cell suspension, washed with enterocin as-48 (25 microg/ml) or with sterile distilled water as control, and stored at different temperatures (-20, 6, 15, 22 degrees c). washing treatments significantly inhibited or completely inactivated l. monocytogenes in strawberries, raspberries, and blackberries stored at 15 ...200819244899
comparison of antimicrobial resistance in escherichia coli, staphylococcus aureus, and listeria monocytogenes strains isolated from organic and conventional poultry meat.the presence of escherichia coli, staphylococcus aureus, and listeria monocytogenes was determined in 55 samples of organic poultry meat and in 61 samples of conventional poultry meat. a total of 220 e. coli, 192 s. aureus, and 71 l. monocytogenes strains were analyzed by an agar disk diffusion assay for their resistance to ampicillin, cephalothin, chloramphenicol, ciprofloxacin, doxycycline, fosfomycin, gentamicin, nitrofurantoin, streptomycin, and sulfisoxazole (e. coli); chloramphenicol, cipr ...200819244911
analysis of additional virulence genes and virulence gene regions in listeria monocytogenes confirms the epidemiologic relevance of multi-virulence-locus sequence typing.previous molecular subtyping studies have defined four epidemic clones (ecs) of listeria monocytogenes (eci, ecii, eciii, and eciv). partial sequences of eight virulence genes were previously shown to be identical within individual ecs of l. monocytogenes. the present study was conducted to determine if the sequences of other virulence genes and virulence gene regions are also conserved within these ecs. six additional virulence genes--bsh, hly, inlj, ipla1, pgda, and srta--and three additional ...200819244915
assessment of safety, nutritional, and spoilage characteristics of different lagoon grey mullets (liza ramada, liza aurata, and liza saliens).different lagoon grey mullets such as liza ramada (thinlip mullet), liza aurata (golden grey mullet), and liza saliens (leaping grey mullet) were analyzed for their nutritional, microbiological, and safety parameters. the microbiological values never exceeded the lower limits stipulated by the italian higher institute of health. the pathogenic species frequently associated with seafood (salmonella, listeria monocytogenes, vibrio cholerae, vibrio parahaemolyticus, and aeromonas hydrophila) were n ...200819244917
identification and analysis of the osmotolerance associated genes in listeria monocytogenes.listeria monocytogenes, the causative agent of listeriosis, has strong osmotolerance and is able to grow in severe circumstances. many studies of the mechanisms of listerial osmotolerance have been performed. however, there is much which remains unknown. in previous studies we constructed two kinds of mutant in l. monocytogenes egd strain to analyse the mechanisms of osmotolerance in l. monocytogenes by molecular genetic methods. in this paper, we summarized the genetical studies of osmotoleranc ...200819238619
[microbiological contamination and antimicrobial activity of cristalised cane sugar on some medically important microorganisms in costa rica].microbiological contamination and antimicrobial activity of cristalised cane sugar on some medically important microorganisms in costa rica. unrefined cristalised cane sugar, obtained after the filtration and evaporation of sugar cane juice, is a nutritional product of traditional consumption in costa rica and other neotropical countries. it has been used in the topic treatment of infected wounds, with satisfactory results even with some antibiotic-ressistant bacteria. we studied the microbiolog ...200819256417
current trends in follow-up of trophoblastic function in ruminant species.during the pregnancy of ruminants, different hormones and proteins are secreted by placenta or corpus luteum allowing the follow up of gestation. among them, progesterone (p4) and pregnancy-associated glycoproteins (pag) were proposed as laboratory tools to establish or to confirm pregnancy diagnosis. in last years, pag assay also provided useful information for researchers working in programs focused on the follow up of trophoblastic function. concentrations of pag appeared as altered after the ...200819261972
evaluation of enterococcus mundtii st4sa and lactobacillus plantarum 423 as probiotics by using a gastro-intestinal model with infant milk formulations as substrate.enterococcus mundtii st4sa and lactobacillus plantarum 423 produce bacteriocins with activity against a number of gram-positive and gram-negative bacteria. both strains survived intestinal conditions simulated in a gastro-intestinal model (gim) with infant milk formulations as substrate and prevented the growth of listeria monocytogenes scotta. the strains are inhibited by the antibiotics amoxicillin, cefadroxil, roxithromycin and doxycycline, anti-inflammatory medicaments containing meloxicam, ...200818963159
structural bioinformatics study of pnp from listeria monocytogenes.this work describes for the first time a model of purine nucleoside phosphorylase from listeria monocytogenes (lmpnp). we modeled the complexes of lmpnp with ligands in order to determine the structural basis for specificity. comparative analysis of the model of lmpnp allowed identification of structural features responsible for ligand affinities.200818855758
the poloxamer p85 is protective against listeria monocytogenes invasion.listeria monocytogenes remains an important foodborne pathogen, and strategies designed to decrease the susceptibility of selected patient populations to foodborne pathogens are therefore desirable. our objective was to determine if the poloxamer p85 was protective against l. monocytogenes infection. caco-2 cells were treated with 0.1% (w/v) p85 and challenged with 10(7) l. monocytogenes egd for 1 hour. a standard gentamicin protection assay was performed to determine invasion differences betwee ...200818991538
microbial quality control of raw ground beef and fresh sausage in casablanca (morocco).in this study, samples of raw ground beef (n = 150) and fresh sausage (n = 100) were collected randomly from butcheries, supermarkets, and fast-food shops, in casablanca, morocco. two types of meat product samples were considered, one with spices (n = 115) and other without spices (n = 135). all the samples were analyzed for the presence of the following bacteria: escherichia coli, staphylococcus, clostridium perfringens, salmonella, and listeria monocytogenes. e. coli strains were further typed ...200819004395
single pre-exposure to a high dose of zymosan enhances lung defense mechanisms and accelerates the pulmonary clearance of a bacterial pathogen in rats.the present study examines the effects of pre-exposure to zymosan (a 1 --> 3-beta-glucan from baker yeast) on lung defense against bacterial infection. rats received a single dose of zymosan a (0.6, 1.2, or 2.5 mg/kg body weight [bw]) or vehicle control (saline) via intratracheal instillation 3 days prior to intratracheal inoculation with 5 x 10(5) listeria monocytogenes. left lungs were homogenized and cultured to assess bacterial clearance, and bronchoalveolar lavage was performed on the right ...200819005921
coordinating innate immune cells to optimize microbial killing.the mechanisms underlying innate immune cell trafficking and activation during infection remain incompletely defined. in this issue of immunity, kang et al. (2008) begin to reveal the cytokine and chemokine cascades that coordinate cellular responses induced by microbial pathogens.200819006691
regulation of hierarchical clustering and activation of innate immune cells by dendritic cells.an early granulomatous response, characterized by collections of white blood cells at foci surrounding pathogens, occurs after infection by many intracellular organisms, including listeria, but how these clusters become organized and for what purpose remain poorly understood. here, we showed that dendritic cell (dc) activation by listeria nucleated rapid clustering of innate cells, including granulocytes, natural killer (nk) cells, and monocytes, to sites of bacteria propagation where interleuki ...200819006696
[nosocomial infection caused by listeria monocytogenes in a patient with a lung transplant]. 200819007574
digest this! a role for autophagy in controlling pathogens.autophagy provides a mechanism for cells to conserve nutrients, but was recently associated with immunity to intracellular pathogens. here, zhao et al. (2008) present direct in vivo evidence that autophagy is linked to macrophage control of toxoplasma gondii and listeria monocytogenes and highlights that this process intersects with cytokine-mediated antimicrobial responses.200818996340
autophagosome-independent essential function for the autophagy protein atg5 in cellular immunity to intracellular pathogens.the physiologic importance of autophagy proteins for control of mammalian bacterial and parasitic infection in vivo is unknown. using mice with granulocyte- and macrophage-specific deletion of the essential autophagy protein atg5, we show that atg5 is required for in vivo resistance to the intracellular pathogens listeria monocytogenes and toxoplasma gondii. in primary macrophages, atg5 was required for interferongamma (ifn-gamma)/lps-induced damage to the t. gondii parasitophorous vacuole membr ...200818996346
short-term genome evolution of listeria monocytogenes in a non-controlled environment.while increasing data on bacterial evolution in controlled environments are available, our understanding of bacterial genome evolution in natural environments is limited. we thus performed full genome analyses on four listeria monocytogenes, including human and food isolates from both a 1988 case of sporadic listeriosis and a 2000 listeriosis outbreak, which had been linked to contaminated food from a single processing facility. all four isolates had been shown to have identical subtypes, sugges ...200819014550
tnf receptor-associated factor 5 is required for optimal t cell expansion and survival in response to infection.receptors belonging to the tnf-receptor (tnf-r) superfamily include important costimulatory molecules, many of which specifically affect t cell activation. tnf receptor-associated factors (trafs) are recruited to many tnf-r superfamily members and are important modulators of the proximal signaling events that occur at the time of receptor engagement and activation. traf5 has been shown to be a positive regulator of a number of these receptors that are involved in t cell costimulation. however, t ...200819017969
cancer immunotherapy using listeria monocytogenes and listerial virulence factors.our laboratory is interested in how immunogenicity may be modulated in vivo in order to better design more effective immunotherapeutics against cancer. our main approach is to use a facultative intracellular bacterium, listeria monocytogenes, which has the unusual ability to live and grow in the cytoplasm of the cell and is thus an excellent vector for targeting passenger antigens to the major histocompatibility complex (mhc) class i pathway of antigen processing with the generation of authentic ...200819018479
fractional differential equations based modeling of microbial survival and growth curves: model development and experimental validation.a fractional differential equations (fdes)-based theory involving 1- and 2-term equations was developed to predict the nonlinear survival and growth curves of foodborne pathogens. it is interesting to note that the solution of 1-term fde leads to the weibull model. nonlinear regression (gauss-newton method) was performed to calculate the parameters of the 1-term and 2-term fdes. the experimental inactivation data of salmonella cocktail in ground turkey breast, ground turkey thigh, and pork shoul ...200819019113
evaluation of antibacterial activity of whey protein isolate coating incorporated with nisin, grape seed extract, malic acid, and edta on a turkey frankfurter system.the effectiveness of whey protein isolate (wpi) coatings incorporated with grape seed extract (gse), nisin (n), malic acid (ma), and ethylenediamine tetraacetic acid (edta) and their combinations to inhibit the growth of listeria monocytogenes, e. coli o157:h7, and salmonella typhimurium were evaluated in a turkey frankfurter system through surface inoculation (approximately 10(6) cfu/g) of pathogens. the inoculated frankfurters were dipped into wpi film forming solutions both with and without t ...200819019119
antibacterial activity of ozone-depolymerized crawfish chitosan.antimicrobial activities of chitosan samples with different molecular weights (1333, 432, 201, 131, and 104 kda) prepared by ozone treatment were examined against 2 gram-positive bacteria (listeria monocytogenes and staphylococcus aureus) and 2 gram-negative bacteria (escherichia coli and pseudomonas fluorescen) to investigate the effect of chitosan's molecular weight and concentration on the inhibition of bacterial growth. antimicrobial activity of chitosan varied depending on the molecular wei ...200819019121
the pta-acka pathway controlling acetyl phosphate levels and the phosphorylation state of the degu orphan response regulator both play a role in regulating listeria monocytogenes motility and chemotaxis.degu is considered to be an orphan response regulator in listeria monocytogenes since the gene encoding the cognate histidine kinase degs is absent from the genome. we have previously shown that degu is involved in motility, chemotaxis and biofilm formation and contributes to l. monocytogenes virulence. here, we have investigated the role of degu phosphorylation in listeria and shown that degs of bacillus subtilis can phosphorylate degu of l. monocytogenes in vitro. we introduced the b. subtilis ...200819019159
inactivation of escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes on stored iceberg lettuce by aqueous chlorine dioxide treatment.inactivation of escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes in iceberg lettuce by aqueous chlorine dioxide (clo(2)) treatment was evaluated. iceberg lettuce samples were inoculated with approximately 7 log cfu/g of e. coli o157:h7, s. typhimurium, and l. monocytogenes. iceberg lettuce samples were then treated with 0, 5, 10, or 50 ppm clo(2) solution and stored at 4 degrees c. aqueous clo(2) treatment significantly decreased the populations of pathogenic bacteria ...200819021812
image analysis based quantification of bacterial volume change with high hydrostatic pressure.scanning electron microscopy (sem) images of staphylococcus aureus 485 and escherichia coli o157:h7 933 were taken after pressure treatments at 200 to 400 mpa. software developed for this purpose was used to analyze sem images and to calculate the change in view area and volume of cells. significant increase in average cell view area and volume for s. aureus 485 was observed in response to pressure treatment at 400 mpa. cell view area for e. coli o157:h7 933 significantly increased at 325 mpa, t ...200819021813
evaluation of changes in listeria monocytogenes populations on frankfurters at different stages from manufacturing to consumption.this study evaluated the fate of inoculated listeria monocytogenes on frankfurters stored under conditions simulating those that may be encountered between manufacturing and consumption. frankfurters with or without 1.5% potassium lactate and 0.1% sodium diacetate (pl/sd) were inoculated (1.8 +/- 0.1 log cfu/cm(2)) with a 10-strain composite of l. monocytogenes, vacuum-packaged, and stored under conditions simulating predistribution storage (24 h, 4 degrees c), temperature abuse during transport ...200819021814
antilisterial activity of hops beta acids in broth with or without other antimicrobials.hops beta acids (hba) are parts of hops flowers used to preserve wort and provide flavor in beer, and are reported as having antimicrobial properties. this study evaluated the antilisterial activity of hba alone or in combination with other known antimicrobials in a culture broth medium. listeria monocytogenes (10-strain mixture) was inoculated (2.6 to 2.8 log cfu/ml) into tryptic soy broth supplemented with 0.6% yeast extract (tsbye) without (control) or with hba (0.5 to 5.0 microg/ml), potassi ...200819021815
cell biology: a listeria escape trick. 200818972010
inhibition of listeria monocytogenes by oregano, cranberry and sodium lactate combination in broth and cooked ground beef systems and likely mode of action through proline metabolism.listeria monocytogenes is a food safety challenge in various food systems including fresh and frozen meat and poultry. natural antimicrobials from plant sources in combination with salts of organic acids have the potential to control l. monocytogenes. in this research the efficiency of water soluble phenolic extracts of oregano and cranberry in combination with sodium lactate was evaluated for control of l .monocytogenes. in both broth and cooked meat studies, the results indicated that the comb ...200818973962
listeriosis. 200818977860
[listeria monocytogenes: old bug, permanent challenge]. 200818949141
[listeria monocytogenes outbreaks: a review of the routes that favor bacterial presence].listeria monocytogenes is a foodborne pathogen that causes serious invasive illness, mainly in certain well-defined high-risk groups, including immunocompromised patients, pregnant women and neonates. l. monocytogenes primarily causes abortion, septicaemia or infections of the central nervous systems. listeriosis outbreaks have mostly been linked to consumption of raw milk or cheese made of unpasteurized milk. previous outbreaks of listeriosis have been linked to a variety of foods especially pr ...200818949142
[listeria monocytogenes infection in pregnancy: experience of pontificia universidad católica de chile university hospital].listeria monocytogenes is gram-positive facultative intracellular pathogen often foodborne and found elsewhere. it is an uncommon cause of illness in the general population. however, it is an important cause of severe infection in neonates, pregnant women, elderly and immunosuppressed patients. listeriosis has unique preference for pregnant women. maternal listeriosis is a diagnostic challenge, and intrauterine infection can lead to severe complications such as amnionitis, preterm labor, spontan ...200818949143
[listeria monocytogenes: report of a rise in pregnant women and literature review].listeria monocytogenes, rare pathogen in the general population, causes serious infections in patients at the extreme ages of life, pregnant woman, and those with immunosuppression. the clinical manifestations are essential to suspect the disease in patients at risk, allowing an early prescription of antimicrobial therapy, before the results of the cultures are available. clinical course and prognosis depends on how early treatment is started and, in pregnant women, the gestational age. in clíni ...200818949144
[microbiological portrait: listeria monocytogenes]. 200818949145
[historical note: in homage to lister].joseph lister, who disputes with klebs the third place as the father of microbiology, was just about to remain without a bacteria immortalizing his ñame. thanks to seeliger, now listeria is used for identifying the genus that pirie had already named listerella in 1927. through a quick review of the history of listeria monocytogenes, we get to know the principal facts in the lives of pirie and seeliger, investigators with absolutely different characters. we also review a brief history of the life ...200818949146
relationship between sublethal injury and microbial inactivation by the combination of high hydrostatic pressure and citral or tert-butyl hydroquinone.the aim was to investigate (i) the occurrence of sublethal injury in listeria monocytogenes, escherichia coli, and saccharomyces cerevisiae after high hydrostatic pressure (hhp) treatment as a function of the treatment medium ph and composition and (ii) the relationship between the occurrence of sublethal injury and the inactivating effect of a combination of hhp and two antimicrobial compounds, tert-butyl hydroquinone (tbhq) and citral. the three microorganisms showed a high proportion of suble ...200818952869
functional impact of mutational activation on the listeria monocytogenes central virulence regulator prfa.the transcriptional activator prfa is required for the expression of virulence factors necessary for listeria monocytogenes pathogenesis. prfa is believed to become activated following l. monocytogenes entry into the cytosol of infected host cells, resulting in the induction of target genes whose products are required for bacterial intracellular growth and cell-to-cell spread. several mutations have been identified that appear to lock prfa into its highly activated cytosolic form (known as prfa* ...200818957610
unusual infections due to listeria monocytogenes in the southern california desert.during the past 22 years, 14 patients have been hospitalized with infection due to listeria monocytogenes at the eisenhower medical center, a regional 300-bed hospital in the desert southwest of southern california. a large number of patients are retired, elderly, and have underlying and often systemic disease.200818922716
cytoplasmic delivery of antigens, by bacillus subtilis enhances th1 responses.endospores of the gram-positive bacterium, bacillus subtilis, have been used successfully for delivery of antigens where the immunogen is expressed on the spore surface. in this work the spore has been engineered to deliver antigens to the cytoplasm of macrophages by expressing listeriolysin o (llo) or a derivative, llo(l461t), that is stable at neutral ph, from the b. subtilis vegetative cell. following phagocytosis spores were shown to germinate in the phagosome enabling secretion of llo/llo(l ...200818809450
effects of irradiation on survival and growth of listeria monocytogenes and natural microflora in vacuum-packaged turkey hams and breast rolls.the effect of electron beam irradiation on the survival and growth of listeria monocytogenes and natural microflora in oven-roasted turkey breast rolls and turkey hams was evaluated. slices of turkey breast rolls and hams were inoculated with a 5-strain mixture of l. monocytogenes to achieve 10(6) to 10(7) cfu/cm2; vacuum-packaged; irradiated at 0 (control), 1.0, 1.5, 2.0, or 2.5 kgy; and stored at 4 degrees c for up to 28 d. numbers of naturally occurring bacteria on sliced turkey hams and brea ...200818809878
novel functions of type i interferons revealed by infection studies with listeria monocytogenes.infection of cells and mice with listeria monocytogenes stimulates production of type i interferons (ifn). these in turn sensitise the listeria host to lethal sequelae of infection with these bacteria. here, we summarise recent findings on the production and biological effects of type i ifn in the course of l. monocytogenes infection.200818926303
development of a quantitative polymerase chain reaction method using a live bacterium as internal control for the detection of listeria monocytogenes.a novel real-time quantitative polymerase chain reaction (q-pcr) assay was developed for rapid and accurate detection of listeria monocytogenes. in this q-pcr assay, a computational dna random shuffling method was used to design an internal amplification control (iac) sequence, which was the same in length and g + c content to the hly amplicon. this iac sequence was inserted into the genome of l. monocytogenes to create a mutant strain named l. monocytogenes-iac. the lm-iac was used as an intern ...200818930623
random mutagenesis identifies novel genes involved in the secretion of antimicrobial, cell wall-lytic enzymes by lactococcus lactis.lactococcus lactis is a gram-positive bacterium that is widely used in the food industry and is therefore desirable as a candidate for the production and secretion of recombinant proteins. previously, we generated a l. lactis strain that expressed and secreted the antimicrobial cell wall-lytic enzyme lysostaphin. to identify lactococcal gene products that affect the production of lysostaphin, we isolated and characterized mutants generated by random transposon mutagenesis that had altered lysost ...200818931288
multilocus genotyping assays for single nucleotide polymorphism-based subtyping of listeria monocytogenes isolates.listeria monocytogenes is responsible for serious invasive illness associated with consumption of contaminated food and places a significant burden on public health and the agricultural economy. we recently developed a multilocus genotyping (mlgt) assay for high-throughput subtype determination of l. monocytogenes lineage i isolates based on interrogation of single nucleotide polymorphisms (snps) via multiplexed primer extension reactions. here we report the development and validation of two add ...200818931295
pathogenicity of listeria monocytogenes scott a after oral and oculonasal challenges of day-old turkey poults.listeria monocytogenes is a ubiquitous, environmental pathogen that has contaminated poultry ready-to-eat products resulting in large-scale recalls. research is needed to determine the source of product and processing plant contamination with l. monocytogenes. the purpose of this study was to compare the oral and oculonasal routes of infection on the pathogenicity of l. monocytogenes in turkey poults under different housing conditions. one-day-old turkey poults were challenged by either route wi ...200818939633
prevalence of listeria monocytogenes in poultry production in france.this study aimed to update and create a data set from laying hens and broilers regarding contamination by listeria monocytogenes. two hundred laying-hen flocks were sampled, with 88 flocks reared in cages and 112 reared on the floor. one hundred forty-five broiler flocks were sampled, with 85 conventional and 60 free-range flocks. a total of 774 and 725 samples were analyzed from laying hens and broilers, respectively. l. monocytogenes was detected in 31 of 200 flocks, yielding an estimated prev ...200818939743
elimination of listeria monocytogenes from vacuum-packed dry-cured ham by e-beam radiation.the inactivation kinetics for listeria monocytogenes scott a (cip 103575, serotype 4b) and listeria innocua (ntc 11288) after e-beam radiation were studied in vacuum-packed ready-to-eat dry-cured ham to optimize the sanitation treatment of this product. a treatment of 1.12 kgy was calculated to reach the food safety objective according to the u.s. department of agriculture criterion. no irradiation treatment is necessary to meet the european union microbiological criterion for this bacterium. no ...200818939744
inactivation kinetics of three listeria monocytogenes strains under high hydrostatic pressure.high hydrostatic pressure (hhp) inactivation of three listeria monocytogenes strains (egde, lo28, and scott a) subjected to 350 mpa at 20 degrees c in aces buffer resulted in survival curves with significant tailing for all three strains. a biphasic linear model could be fitted to the inactivation data, indicating the presence of an hhp-sensitive and an hhp-resistant fraction, which both showed inactivation according to first-order kinetics. inactivation parameters of these subpopulations of the ...200818939745
survival of listeria monocytogenes in a simulated dynamic gastrointestinal model during storage of inoculated bologna and salami slices in vacuum packages.listeria monocytogenes counts were determined during storage (82 days, 4 degrees c) in vacuum packages of inoculated bologna and salami slices and after exposure to a simulated dynamic model of the stomach and small intestine. variables controlled in the model included gastric emptying and gastrointestinal fluid secretion rates, gradual gastric acidification, and intestinal ph maintenance. l. monocytogenes populations increased on bologna and decreased on salami, reaching 8.7 and 1.4 log cfu/g, ...200818939746
rechargeable antimicrobial surface modification of polyethylene.polyethylene films were surface modified, to incorporate amine and amide functionalities, and subsequently were evaluated for their ability to recharge the antimicrobial n-halamine structures after contact with sodium hypochlorite, a common food-approved sanitizer. surfaces were tested for chlorine retention and release, as well as antimicrobial activity against microorganisms relevant to food quality and food safety, including escherichia coli k-12, pseudomonas fluorescens, bacillus cereus, and ...200818939750
transmission electron microscopy study of listeria monocytogenes treated with nisin in combination with either grape seed or green tea extract.the objective of this study was to use transmission electron microscopy to investigate the morphological changes that occurred in listeria monocytogenes cells treated with grape seed extract (gse), green tea extract (gte), nisin, and combinations of nisin with either gse or gte. the test solutions were prepared with (i) 1% gse, 1% gte, 6,400 iu of nisin, and the combination of these dilutions with nisin or with (ii) the pure major phenolic constituents of gse (0.02% epicatechin plus 0.02% catech ...200818939761
comparison of four commercial dna extraction kits for pcr detection of listeria monocytogenes, salmonella, escherichia coli o157:h7, and staphylococcus aureus in fresh, minimally processed vegetables.four commercial dna extraction methods, prepman ultra (applied biosystems), instagene matrix (biorad), dneasy tissue kit (qiagen), and ultraclean (mobio), were tested for pcr detection of listeria monocytogenes, escherichia coli o157: h7, salmonella, and staphylococcus aureus in fresh, minimally processed vegetables. for comparative purposes, sensitivity assays with specific pcrs were carried out after dna extraction with the four methods in green pepper, broccoli, and onion artificially inocula ...200818939762
ox40 costimulatory signals potentiate the memory commitment of effector cd8+ t cells.a t cell costimulatory molecule, ox40, contributes to t cell expansion, survival, and cytokine production. although several roles for ox40 in cd8(+) t cell responses to tumors and viral infection have been shown, the precise function of these signals in the generation of memory cd8(+) t cells remains to be elucidated. to address this, we examined the generation and maintenance of memory cd8(+) t cells during infection with listeria monocytogenes in the presence and absence of ox40 signaling. we ...200818941188
exploring regulatory mechanisms of cd8+ t cell contraction.a small fraction of the cd8 t cell effector population that responds to an infection progresses through the contraction phase to the memory stage. the factors regulating the extent of contraction are poorly understood. competition for limited resources has been widely postulated to be the cause of cell death during the contraction phase, but our data show that competition does not affect contraction kinetics. we go on to demonstrate that all effector cells present at the peak of the response hav ...200818946035
antimicrobial activity of endemic crataegus tanacetifolia (lam.) pers and observation of the inhibition effect on bacterial cells.up to now an increasing number of antibiotic-resistant bacteria have been reported and thus new natural therapeutic agents are needed in order to eradicate these pathogens. through the discovery of plants such as crataegus tanacetifolia (lam.) pers that have antimicrobial activity, it will be possible to discover new natural drugs serving as chemotherapeutic agents for the treatment of nosocomial pathogens and take these antibiotic-resistant bacteria under control. the objective of the present s ...200818946875
lactococcus lactis-expressing listeriolysin o (llo) provides protection and specific cd8(+) t cells against listeria monocytogenes in the murine infection model.lactococcus lactis has previously been proposed as a vaccine platform for the safe delivery of heterologous antigens. here we utilized l. lactis as a live vector for expression of listeriolysin o (llo), a major listeria monocytogenes antigen and virulence factor. a variety of plasmid constructs were designed to permit either constitutive or nisin-inducible expression of secreted or non-secreted llo in l. lactis. recombinant strains were subsequently tested in a murine model for vaccination effic ...200818691625
enhanced gene delivery using disulfide-crosslinked low molecular weight polyethylenimine with listeriolysin o-polyethylenimine disulfide conjugate.one of the most important requirements for non-viral gene delivery systems is the ability to mediate high levels of gene expression with low toxicity. after the dna/vector complexes are taken up by cells through endocytosis, dna is typically contained within the endocytic compartments and rapidly degraded due to the low ph and hydrolytic enzymes within endosomes and lysosomes, limiting its accessibility to the cytosol and ultimately to the nucleus. in this study, the endosomolytic protein lister ...200818692533
biodiversity of the microbial community in a spanish farmhouse cheese as revealed by culture-dependent and culture-independent methods.the microbial diversity within alberquilla cheese, made from a spontaneously fermented mixture of raw goats' and sheep's milk in the alpujarra mountains (granada, south-east spain), has been studied by the classical culturing method and also by molecular analysis of community dna. a collection of 206 isolates was obtained from the cheese on different selective/differential media, which were then re-grouped to 52 after randomly amplified polymorphic dna (rapd)-pcr analyses. isolates on man-rogosa ...200818692931
the actin propulsive machinery: the proteome of listeria monocytogenes tails.actin-based comet tails produced by listeria monocytogenes are considered as representative models for cellular force-producing machineries crucial for cell migration. we here present a proteomic picture of these tails formed in extracts from brain and platelets. this provides a comprehensive view, revealing high molecular complexity and novel host cell proteins as tail components, and suggests the participation of specific multicomponent regulatory complexes. this work forms a new basis to expa ...200818694727
a high-throughput comparison of recombinant gene expression parameters for e. coli-mediated gene transfer to p388d1 macrophage cells.escherichia coli strain bl21(de3) was tested as a delivery vector for gene transfer to a murine p388d1 macrophage cell line using a 96-well high-throughput assay. five recombinant strains of e. coli were compared to identify the effect recombinant listeriolysin o (llo) and associated gene expression parameters had on final delivery of a luciferase reporter gene. listeriolysin o, native to listeria monocytogenes and used here in an effort to improve final gene delivery, was expressed from plasmid ...200818694790
chronic type a aortic dissection associated with listeria monocytogenes infection.a previously healthy 77-year-old woman with a 4-week history of back pain and fever was admitted to our hospital for chronic type a aortic dissection. the aortic arch was enlarged to 7.5 cm in diameter, and the large dissecting aortic aneurysm involved all three branches of the aortic arch and compressed the trachea. laboratory tests showed an increased c-reactive protein level (10.5 mg/dl). blood cultures performed upon admission were negative. progression of the symptoms suggested the possibil ...200818696209
anti-inflammatory, gastroprotective, free-radical-scavenging, and antimicrobial activities of hawthorn berries ethanol extract.hawthorn [crataegus monogyna jacq. and crataegus oxyacantha l.; sin. crataegus laevigata (poiret) dc., rosaceae] leaves, flowers, and berries are used in traditional medicine in the treatment of chronic heart failure, high blood pressure, arrhythmia, and various digestive ailments, as well as geriatric and antiarteriosclerosis remedies. according to european pharmacopoeia 6.0, hawthorn berries consist of the dried false fruits of these two species or their mixture. the present study was carried ...200818698794
genome-wide analyses reveal lineage specific contributions of positive selection and recombination to the evolution of listeria monocytogenes.the genus listeria includes two closely related pathogenic and non-pathogenic species, l. monocytogenes and l. innocua. l. monocytogenes is an opportunistic human foodborne and animal pathogen that includes two common lineages. while lineage i is more commonly found among human listeriosis cases, lineage ii appears to be overrepresented among isolates from foods and environmental sources. this study used the genome sequences for one l. innocua strain and four l. monocytogenes strains representin ...200818700032
mode of action of antimicrobial peptide p45 on listeria monocytogenes.the mode of action of an antimicrobial peptide produced by bacillus sp. p45 isolated from the intestine of the amazonian basin fish piaractus mesopotamicus was investigated. the antimicrobial peptide was purified from culture supernatants by precipitation with ammonium sulfate and gel filtration chromatography. the peptide has an ec(50) of 300 au (activity units) ml(-1) and kills all viable cells of listeria monocytogenes with a concentration of 800 au ml(-1). a decrease in od was observed when ...200818702075
[study by multiplex pcr of listeria monocytogenes serotypes isolated in argentine].a multiplex pcr assay, recently validated to characterize the serotypes of listeria monocytogenes was evaluated in comparison to conventional serotyping. three hundred forty two l. monocytogenes strains isolated from human, food, animal and environmental sources during the 1992-2005 period were assayed. the concordance between the two methods for serotypes 1/2a, 1/2b and 1/2c was 100%, whereas for serotype 4b it was 98%. serotyping is a useful tool for first line strain differentiation during ep ...200818705488
antimicrobial effects of turkish propolis, pollen, and laurel on spoilage and pathogenic food-related microorganisms.the antimicrobial activities of propolis extract, pollen extract, and essential oil of laurel (laurus nobilis l.) at concentrations from 0.02% to 2.5% (vol/vol) were investigated on bacteria (bacillus cereus, bacillus subtilis, escherichia coli, salmonella typhimurium, staphylococcus aureus, yersinia enterocolitica, enterococcus faecalis, and listeria monocytogenes), yeasts (saccharomyces cerevisiae and candida rugosa), and molds (aspergillus niger and rhizopus oryzae). pollen has no antimicrobi ...200818800911
pillars article: development of th1 cd4+ t cells through il-12 produced by listeria-induced macrophages. 1993. science 260(5107): 547-549. 200818802044
infection of myeloid dendritic cells with listeria monocytogenes leads to the suppression of t cell function by multiple inhibitory mechanisms.myeloid dendritic cells (dc) and macrophages play an important role in pathogen sensing and antimicrobial defense. in this study we provide evidence that myeloid dc respond to infection with listeria monocytogenes with simultaneous induction of multiple stimulatory and inhibitory molecules. however, the overall impact of infected dc during t cell encounter results in suppression of t cell activation, indicating that inhibitory pathways functionally predominate. inhibitory activity of infected dc ...200818802101
antimicrobial efficacy of citron essential oil on spoilage and pathogenic microorganisms in fruit-based salads.the aim of this study was the evaluation of the effects of pure citral and citron essential oil on microbial spoilage and growth and survival of pathogenic microorganisms during storage. they were added in the syrup of industrial ready-to-eat fruit salads stored at 9 degrees c. both citral (25 to 125 ppm) and citron essential oil (300, 600, 900 ppm) were able to prolong the microbial shelf life of the fruit-based salads. the essential oil gave excellent results, avoiding the undesirable effects ...200818803716
resistance of nutrient-deprived listeria monocytogenes 10403s and a deltasigb mutant to chemical stresses in the presence or absence of oxygen.nutrient-deprived listeria monocytogenes have increased resistance to processing control measures. heat-stressed l. monocytogenes cells produce higher counts under anaerobic conditions and sigb reportedly contributes to the survival of environmentally stressed gram-positive bacteria. in this study, a wild type (wt) strain, l. monocytogenes 10403s, and a deltasigb mutant, fsla1-254, were stressed by starvation in phosphate buffered saline coupled with exposure to chemicals with/without oxygen. in ...200818803717
wasp identity theft by a bacterial effector.espf(u), a protein secreted by pathogenic enterohaemorrhagic e. coli (ehec), activates n-wasp/wasp to induce actin pedestal formation in host cells. two recent papers in nature show that espf(u) exploits a wasp activation strategy so extreme that it may effectively sequester wasp, blinding it to both autoinhibition and cellular regulation.200818804428
gene expression profiling of listeria monocytogenes strain f2365 during growth in ultrahigh-temperature-processed skim milk.to study how listeria monocytogenes survives and grows in ultrahigh-temperature-processed (uht) skim milk, microarray technology was used to monitor the gene expression profiles of strain f2365 in uht skim milk. total rna was isolated from strain f2365 in uht skim milk after 24 h of growth at 4 degrees c, labeled with fluorescent dyes, and hybridized to "custom-made" commercial oligonucleotide (35-mers) microarray chips containing the whole genome of l. monocytogenes strain f2365. compared to l. ...200818806004
identification of components of the sigma b regulon in listeria monocytogenes that contribute to acid and salt tolerance.sigma b (sigma(b)) is an alternative sigma factor that controls the transcriptional response to stress in listeria monocytogenes and is also known to play a role in the virulence of this human pathogen. in the present study we investigated the impact of a sigb deletion on the proteome of l. monocytogenes grown in a chemically defined medium both in the presence and in the absence of osmotic stress (0.5 m nacl). two new phenotypes associated with the sigb deletion were identified using this mediu ...200818806006
inflammation and autoimmunity caused by a shp1 mutation depend on il-1, myd88, and a microbial trigger.a recessive phenotype called spin (spontaneous inflammation) was induced by n-ethyl-n-nitrosourea (enu) mutagenesis in c57bl/6j mice. homozygotes display chronic inflammatory lesions affecting the feet, salivary glands and lungs, and antichromatin antibodies. they are immunocompetent and show enhanced resistance to infection by listeria monocytogenes. tlr-induced tnf and il-1 production are normal in macrophages derived from spin mice. the autoinflammatory phenotype of spin mice is fully suppres ...200818806225
conjugated action of two species-specific invasion proteins for fetoplacental listeriosis.the ability to cross host barriers is an essential virulence determinant of invasive microbial pathogens. listeria monocytogenes is a model microorganism that crosses human intestinal and placental barriers, and causes severe maternofetal infections by an unknown mechanism. several studies have helped to characterize the bacterial invasion proteins inla and inlb. however, their respective species specificity has complicated investigations on their in vivo role. here we describe two novel and com ...200818806773
bacterial infection alters the kinetics and function of inkt cell responses.cd1d-restricted valpha14 invariant nkt cells (inkt) are innate-like, immunoregulatory lymphocytes that play critical roles in autoimmunity, tumor surveillance, and infectious disease. although inkt cells are activated during microbial infection, the impacts of infection on the function of inkt cells have not been fully characterized. using a listeria monocytogenes (lm) infection model, we found that inkt cells failed to expand after infection, resulting in prolonged loss in the spleen, in contra ...200818772281
a new perspective on listeria monocytogenes evolution.listeria monocytogenes is a model organism for cellular microbiology and host-pathogen interaction studies and an important food-borne pathogen widespread in the environment, thus representing an attractive model to study the evolution of virulence. the phylogenetic structure of l. monocytogenes was determined by sequencing internal portions of seven housekeeping genes (3,288 nucleotides) in 360 representative isolates. fifty-eight of the 126 disclosed sequence types were grouped into seven well ...200818773117
xbp1 links er stress to intestinal inflammation and confers genetic risk for human inflammatory bowel disease.inflammatory bowel disease (ibd) has been attributed to aberrant mucosal immunity to the intestinal microbiota. the transcription factor xbp1, a key component of the endoplasmic reticulum (er) stress response, is required for development and maintenance of secretory cells and linked to jnk activation. we hypothesized that a stressful environmental milieu in a rapidly proliferating tissue might instigate a proinflammatory response. we report that xbp1 deletion in intestinal epithelial cells (iecs ...200818775308
listeria monocytogenes, a unique model in infection biology: an overview.this review rather than covering the whole field intends to highlight recent findings on the listeria monocytogenes infectious process or some listeria specific traits, place them within the framework of well-established data, and demonstrate how this gram-positive bacterium has, in two decades, emerged as a multifaceted paradigm. indeed, the cell biology of the infectious process has been deciphered in great detail and provided insights in both the way bacterial pathogen manipulate the host and ...200818775788
modelling the competitive growth between listeria monocytogenes and biofilm microflora of smear cheese wooden shelves.the aim of this study was to investigate the mechanism of the observed inhibition of listeria monocytogenes by the natural biofilm microflora (bm) on wooden shelves used in the ripening of a soft and smear cheese. for this, bm was harvested and we conducted a series of experiments in which two strains of l. monocytogenes were co-cultured with bm on glass fiber filters deposited on model cheeses. compared to monoculture, l. monocytogenes growth rate in co-culture was not reduced but the growth of ...200818778863
temperature governs the inactivation rate of vegetative bacteria under growth-preventing conditions.novel studies, in combination with a meta-analysis of available data, were undertaken to explore the kinetics of non-thermal inactivation of escherichia coli with particular attention to inactivation in fermented meats and including analogous broth-based model systems. the analyses were based on rates of inactivation and specifically investigated the influence of temperature, ph and water activity at levels that alone, or in combination, prevented growth. when independently-derived inactivation ...200818778864
[spontaneus abortion caused by listeria monocytogenes--report of three cases].this paper describes three cases of spontaneous abortion caused by listeria monocytogenes which were diagnosed during the outbreak of listeriosis in late 2006. both clinical and morphological features were highly consistent. the abortion between 19 and 20 weeks of gestation was preceded by high maternal fever. the fetal disease was miliary widespread with involvement of adrenals, liver and lungs in particular. there was always present a pustular rash. histological examination of the placentas re ...200818783138
ceramide in bacterial infections and cystic fibrosis.ceramide is formed by the activity of sphingomyelinases, by degradation of complex sphingolipids, reverse ceramidase activity or de novo synthesized. the formation of ceramide within biological membranes results in the formation of large ceramide-enriched membrane domains. these domains serve the spatial and temporal organization of receptors and signaling molecules. the acid sphingomyelinase-ceramide system plays an important role in the infection of mammalian host cells with bacterial pathogen ...200818783339
[molecular typing of listeria monocytogenes isolated from foodstuff in guangdong province by pulsed-field gel electrophoresis].to establish molecular typing of listeria monocytogenes isolates by pulsed-field gel electrophoresis (pfge) for studying the epidemiologic characteristics of listeria monocytogenes isolated from foodstuff in guangdong province and to build up pfge typing database of listeria monocytogenes isolates for identifying the infectious resource of the outbreaks and other epidemiologic investigation.200818785476
cloning, sequencing and analysis of dnak -dnaj gene cluster of bacillus megaterium.the dna fragment of heat shock genes (hrca-grpe-dnak-dnaj) containing complete hrca-grpe-dnak operon and the transcription unit of dnaj was cloned, sequensed and analyzed from bacillus megaterium rf5. the sequence of hrca, grpe and dnaj were first time reported, and their coding products exibit 60%, 63% and 81% of identities to the homologs of b. subtilis. a sigmaa-type promoter of gram-positive bacteria (pa1) and a terminator were located upstream of the hrca and downstream of dnak, and a contr ...200818785662
listeriosis: a primer. 200818787096
listeriolysin s, a novel peptide haemolysin associated with a subset of lineage i listeria monocytogenes.streptolysin s (sls) is a bacteriocin-like haemolytic and cytotoxic virulence factor that plays a key role in the virulence of group a streptococcus (gas), the causative agent of pharyngitis, impetigo, necrotizing fasciitis and streptococcal toxic shock syndrome. although it has long been thought that sls and related peptides are produced by gas and related streptococci only, there is evidence to suggest that a number of the most notorious gram-positive pathogenic bacteria, including listeria mo ...200818787690
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