Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
[listeriosis]. 199910088413
functional deficiencies of peritoneal cells from gene-targeted mice lacking g-csf or gm-csf.gene-targeted mice lacking the hemopoietic growth factors, granulocyte colony-stimulating factor (g-csf) or granulocyte-macrophage (gm)-csf, show increased susceptibility to infection with the facultative intracellular bacterium, listeria monocytogenes. the resident peritoneal cell populations from g-csf(-/-) and gm-csf(-/-) mice showed reduced production of the bactericidal molecule nitric oxide. macrophage-mediated tumoricidal activity and phagocytosis of listeria were reduced in g-csf(-/-), b ...199910088609
lps down-regulates the expression of chemokine receptor ccr2 in mice and abolishes macrophage infiltration in acute inflammation.interactions between chemokines and their specific receptors are important for leukocyte trafficking. the cc-chemokine monocyte chemoattractant protein-1 (mcp-1) and its specific receptor ccr2 are essential in monocytic infiltration and have been associated with several inflammatory diseases. it has been reported that several endotoxin and proinflammatory cytokines inhibit ccr2 expression in vitro in human monocytes. we report here that lipopolysaccharides (lps) down-regulated ccr2 expression bo ...199910088610
isolation and detection of listeria monocytogenes using fluorogenic and chromogenic substrates for phosphatidylinositol-specific phospholipase c.the bcm listeria monocytogenes detection system (lmds) consists of a selective preenrichment broth (lmpeb), selective enrichment broth (lmseb), selective/differential plating medium (lmpm), and identification on a confirmatory plating medium (lmcm). the efficacy of the bcm lmds was determined using pure cultures and naturally and artificially contaminated environmental sponges. the bcm lmpeb allowed the growth of listeria and resuscitation of heat-injured l. monocytogenes. the bcm lmseb, which c ...199910090243
application of reuterin produced by lactobacillus reuteri 12002 for meat decontamination and preservation.lactobacillus reuteri strain 12002 was used for reuterin production in the two-step fermentation process. a batch culture fermentation was used to produce a maximum biomass of l. reuteri. then cells were harvested, resuspended in a glycerol-water solution, and anaerobically incubated to produce reuterin. the lyophilized supernatants (approximately 4000 activity units (au) of reuterin per ml) were diluted in distilled water for decontamination and preservation trials. the mic values of reuterin f ...199910090245
the mycobacterium tuberculosis reca intein can be used in an orftrap to select for open reading frames.the dna repair protein reca of mycobacterium tuberculosis contains an intein, a self-splicing protein element. we have employed this mtu reca intein to create a selection system for successful intein splicing by inserting it into a kanamycin-resistance gene so that functional antibiotic resistance can only be restored upon protein splicing. we then proceeded to develop an orftrap, i.e., a selection system for the cloning of open reading frames (orfs). the orftrap exploits the self-splicing prope ...199910091667
spectrum and antimicrobial activity of alexomycin (pnu-82, 127), a peptide compound projected for use in animal health.alexomycin (pnu-82, 127) is a thiopeptide antimicrobial complex intended for veterinary practice that belongs to a series of cyclic peptides produced by streptomyces arginensis. mics against selected routine and fastidious clinical isolates of animal and human origin were determined by broth microdilution or agar dilution reference methods. alexomycin was active against gram-positive pathogens such as oxacillin-susceptible and -resistant staphylococcus aureus and coagulase-negative staphylococci ...199910092967
detection of listeria monocytogenes in milk by the polymerase chain reaction.a on the polymerase chain reaction (pcr) method based was developed for detection of listeria monocytogenes in milk samples after enrichment culture. it consists of culturing samples in listeria enrichment broth, followed by dna extraction and detection of the organism using pcr. dilutions of l. monocytogenes in milk were subjected to pcr amplification after enrichment culture. when determining the sensitivity of the method, it was found to be possible to detect 37 cfu (colony forming unit gl/ml ...199910096164
characterization of listeria monocytogenes from an ice cream plant by serotyping and pulsed-field gel electrophoresis.one dominating strain of serotype 1/2b was found when serotyping and pulsed-field gel electrophoresis (pfge) patterns were used for the characterization of 41 listeria monocytogenes isolates originating from an ice cream plant. samples were taken from the production environment, equipment and ice cream during the years 1990-1997. serotyping divided the isolates into two serovars, 1/2b and 4b. three rare-cutting enzymes (apai, asci and smai) were used in the creation of pfge patterns. asci result ...199910100898
a model describing the relationship between regrowth lag time and mild temperature increase for listeria monocytogenes.in order to comply with the consumer demand for ready-to-eat and look 'fresh' products, mild heat treatment will be used more and more in the agrofood industry. nonetheless there is no tool to define the most appropriate mild heat treatment. in order to build this tool, it is necessary to study and describe the response of a bacterial population to a mild increase in temperature, from the dynamic point of view. the response to a mild increase in temperature, defined by stress duration and temper ...199910100905
comparative survival of salmonella typhimurium dt 104, listeria monocytogenes, and escherichia coli o157:h7 in preservative-free apple cider and simulated gastric fluid.this study compared the survival of three-strain mixtures (ca. 10(7) cfu ml(-1) each) of salmonella typhimurium dt104, listeria monocytogenes, and escherichia coli o157:h7 in pasteurized and unpasteurized preservative-free apple cider (ph 3.3-3.5) during storage at 4 and 10 degrees c for up to 21 days. s. typhimurium dt104 populations decreased by <4.5 log10 cfu ml(-1) during 14 days storage at 4 and 10 degrees c in pasteurized cider, and by > or =5.5 log10 cfu ml(-1) during 14 days in unpasteur ...199910100906
differential expression of listeria monocytogenes virulence genes in mammalian host cells.we have used rt-pcr and gfp-mediated fluorescence to analyse the regulation of prfa-dependent virulence genes of listeria monocytogenes during proliferation in mammalian host cells. our data show that most of the prfa-regulated virulence genes are more efficiently expressed, as measured by transcript levels, when l. monocytogenes is grown in macrophages and macrophage-like cells rather than in epithelial cells, hepatocytes or endothelial cells. the promoters for hly and plca are predominantly ac ...199910102368
effector cells of both nonhemopoietic and hemopoietic origin are required for interferon (ifn)-gamma- and tumor necrosis factor (tnf)-alpha-dependent host resistance to the intracellular pathogen, toxoplasma gondii.although interferon (ifn)-gamma-activated, mononuclear phagocytes are considered to be the major effectors of resistance to intracellular pathogens, it is unclear how they control the growth of microorganisms that reside in nonhemopoietic cells. pathogens within such cells may be killed by metabolites secreted by activated macrophages or, alternatively, directly controlled by cytokine-induced microbicidal mechanisms triggered within infected nonphagocytic cells. to distinguish between these two ...199910190899
cpg-containing oligonucleotides are efficient adjuvants for induction of protective antiviral immune responses with t-cell peptide vaccines.synthetic nonmethylated oligonucleotides containing cpg dinucleotides (cpg-odns) have been shown to exhibit immunostimulatory activity. cpg-odns have the capacity to directly activate b cells, macrophages, and dendritic cells, and we show here that this is reflected by cell surface binding of oligonucleotides to these cell subsets. however, t cells are not directly activated by cpg-odns, which correlates with the failure to bind to the t-cell surface. efficient competition for cpg-induced b-cell ...199910196308
effect of elevated oxygen and carbon dioxide on the surface growth of vegetable-associated micro-organisms.the impact of a novel type of modified atmosphere (ma), referred to as high o2-ma, on micro-organisms associated with the spoilage of minimally-processed vegetables was studied. pure cultures of pseudomonas fluorescens, enterobacter agglomerans, aureobacterium strain 27, candida guilliermondii, c. sake, salmonella typhimurium, salm. enteritidis, escherichia coli, listeria monocytogenes, leuconostoc mesenteroides var. mesenteroides, lactobacillus plantarum and lactococcus lactis were cultured on ...199910196748
effect of osmotic, alkaline, acid or thermal stresses on the growth and inhibition of listeria monocytogenes.five strains of listeria monocytogenes (a, b, c, d and e) isolated from industrial plants have been subjected to different osmotic, alkaline, acid or thermal stresses. the effects of these treatments on lag-phase (l) and growth rate (mu) of cells in mid-log phase have been followed using an automated optical density monitoring system. increasing the osmotic pressure by the addition of different amounts of nacl increased the lag phase and decreased the growth rate. the same phenomena were observe ...199910196752
response to high-pressure, low-temperature treatment in vegetables: determination of survival rates of microbial populations using flow cytometry and detection of peroxidase activity using confocal microscopy.application of high hydrostatic pressure (200, 300, 350 and 400 mpa) at 5 degrees c for 30 min to different micro-organisms, including gram-positive and gram-negative bacteria, moulds and yeasts, proved to be more effective in inactivating these organisms than treatments at 20 degrees c for 10 min and at 10 degrees c for 20 min. moulds, yeasts, gram-negative bacteria and listeria monocytogenes were most sensitive, and their populations were completely inactivated at pressures between 300 and 350 ...199910196760
behaviour of listeria monocytogenes under combined chilling processes.the behaviour of listeria monocytogenes under chilling processes was investigated. growth kinetics were measured at 7 degrees c in tsbye culture medium as a function of ph (7.2 and 6.2), pre-incubation temperatures (4 or 7 degrees c), cooling (0.05 or 0.1 degree c min-1) and freezing (0 and -5 degrees c) treatments. growth curves generated were fitted by gompertz and baranyi functions. the baranyi function gave better parameter estimation values than the gompertz equation which over-estimated th ...199910196772
biopreservation in modified atmosphere stored mungbean sprouts: the use of vegetable-associated bacteriocinogenic lactic acid bacteria to control the growth of listeria monocytogenes.two bacteriocinogenic strains of pediococcus parvulus and one bacteriocinogenic enterococcus mundtii strain were evaluated for their potential to control the growth of listeria monocytogenes on refrigerated, modified atmosphere (ma) stored mungbean sprouts. these three strains, which were isolated from minimally-processed vegetables, were shown to grow in culture broth at 4, 8, 15 and 30 degrees c. however, only ent. mundtii was capable of bacteriocin production at 4-8 degrees c. examination of ...199910196774
the origin and function of soluble cd14 in experimental bacterial meningitis.murine experimental meningitis models induced by either escherichia coli lps, live streptococcus pneumoniae, or listeria monocytogenes were used to study the origin and potential function of soluble cd14 (scd14) in the brain during bacterial meningitis. whereas intracerebral infection caused only a minor and/or transient increase of scd14 levels in the serum, dramatically elevated concentrations of scd14 were detected in the cerebrospinal fluid. reverse-transcriptase pcr and facs analysis of the ...199910202018
enhancement of the listeria monocytogenes p60-specific cd4 and cd8 t cell memory by nonpathogenic listeria innocua.the contact of t cells to cross-reactive antigenic determinants expressed by nonpathogenic environmental micro-organisms may contribute to the induction or maintenance of t cell memory. this hypothesis was evaluated in the model of murine listeria monocytogenes infection. the influence of nonpathogenic l. innocua on the l. monocytogenes p60-specific t cell response was analyzed. we show that some cd4 t cell clones raised against purified p60 from l. monocytogenes cross-react with p60 purified fr ...199910202020
increased expression of rab5a correlates directly with accelerated maturation of listeria monocytogenes phagosomes.previous studies have shown that listeria monocytogenes (lm) modulates phagocytic membrane traffic. here we explore whether rab5a, a gtpase associated with phagosome-endosome fusion, is related to phagosome maturation and to the intracellular survival of lm. stable transfection of rab5a cdna into macrophages accelerates intracellular degradation of lm. morphological studies confirmed that phagosome maturation and phagosome-lysosome fusion is enhanced by overexpression of rab5a. down-regulation e ...199910206948
rapid detection of listeria monocytogenes by a pcr assay specific for an aminopeptidase.specific and rapid detection of listeria monocytogenes is very important with regard to food safety since all other species of listeria appear to be non-pathogenic to humans. conventional microbiological detection methods are very time consuming. the polymerase chain reaction (pcr) is one of the most promising techniques for rapid detection of micro-organisms in food products. we have developed a pcr assay, specific for l. monocytogenes, based on the gene encoding an aminopeptidase, which previo ...199910208803
delivery of protein to the cytosol of macrophages using escherichia coli k-12.listeriolysin o (llo) is an essential determinant of pathogenicity whose natural biological role is to mediate lysis of listeria monocytogenes containing phagosomes. in this study, we report that escherichia coli expressing cytoplasmic recombinant llo can efficiently deliver co-expressed proteins to the cytosol of macrophages. we propose a model in which subsequent or concomitant to phagocytosis the e. coli are killed and degraded within phagosomes causing the release of llo and target proteins ...199910209738
listeriolysin o-dependent activation of endothelial cells during infection with listeria monocytogenes: activation of nf-kappa b and upregulation of adhesion molecules and chemokines.the facultative intracellular bacterium listeria monocytogenes is an invasive pathogen that crosses the vascular endothelium and disseminates to the placenta and the central nervous system. its interaction with endothelial cells is crucial for the pathogenesis of listeriosis. by infecting in vitro human umbilical vein endothelial cells (huvec) with l. monocytogenes, we found that wild-type bacteria induced the expression of the adhesion molecules (icam-1 and e-selectin), chemokine secretion (il- ...199910209744
in vitro efficacy of n-duopropenide, a recently developed disinfectant containing quaternary ammonium compounds, against selected gram-positive and gram-negative organisms.to study the efficacy of n-duopropenide against various gram-positive and gram-negative organisms.199910211693
adherence of listeria monocytogenes strains to stainless steel coupons.an assay was developed to measure the number of listeria monocytogenes cells adhering to stainless steel, and was used to investigate the adherence of 111 strains of the organism, which included representatives with respect to serotype, carriage of plasmids, source and persistence in the food processing environment. growth and adherence curves of four l. monocytogenes strains over 48 h were obtained. while the growth curves of all four micro-organisms were seen to reach similar levels at station ...199910212403
response surface methodology, an approach to predict the effects of a lactoperoxidase system, nisin, alone or in combination, on listeria monocytogenes in skim milk.experimental designs using response surface methodology (rsm) were used to determine effects and interactions of nisin (0-200 i.u. ml-1), ph values (5.4-6.6), incubation time (0-36 h or 0-144 h) and the lactoperoxidase-thiocyanate-hydrogen peroxide system (lps) on listeria monocytogenes cip 82110 in skim milk, at 25 degrees c. the lps varied from level 0-2; lps at level 1 consisted of lactoperoxidase (35 mg l-1), thiocyanate (25 mg l-1) and h2o2, which was supplied exogenously by glucose-oxidase ...199910212409
development and evaluation of a 24 well microtitre plate method for isolation of listeria spp. or listeria monocytogenes from foods.a rapid and simple method (24m) using 24 well microtitre plates was developed to determine the presence of listeria monocytogenes or listeria spp. in food samples. the 24m was composed of two 24 well microtitre plates connected with a yellow tip. the 24m was evaluated with pathogen cocktails and ground beef samples and compared with the conventional method for presumptive identification of listeria spp. only food-borne pathogen cocktails and ground beef samples containing l. monocytogenes or lis ...199910212440
high pressure response of fruit jams contaminated with listeria monocytogenes.high pressure is an alternative to thermal processing and is used to preserve food. listeria monocytogenes is a bacterium which grows at low temperature, is able to multiply under vacuum, and is responsible for food poisoning. pressures of 100, 200, 300 and 400 mpa were used for 5, 10 and 15 min at 20 degrees c on pure culture, and on apple and plum jam baby food artificially contaminated with listeria. pure culture was also to test pressures of 200, 300, 350 and 400 mpa at 5 degrees c for 30 mi ...199910212445
antiorthostatic suspension stimulates profiles of macrophage activation in mice.the antiorthostatic suspension model simulates certain physiological effects of spaceflight. we have previously reported bdf1 mice suspended by the tail in the antiorthostatic orientation for 4 days express high levels of resistance to virulent listeria monocytogenesinfection. in the present study, we examined whether the increased resistance to this organism correlates with profiles of macrophage activation, given the role of the macrophage in killing this pathogen in vivo. we infected bdf1 mic ...199910213913
typing of listeria monocytogenes strains by repetitive element sequence-based pcr.listeria monocytogenes strains possess short repetitive extragenic palindromic (rep) elements and enterobacterial repetitive intergenic consensus (eric) sequences. we used repetitive element sequence-based pcr (rep-pcr) to evaluate the potential of rep and eric elements for typing l. monocytogenes strains isolated from humans, animals, and foods. on the basis of rep-pcr fingerprints, l. monocytogenes strains were divided into four major clusters matching origin of isolation. rep-pcr fingerprints ...19999854072
sources of listeria monocytogenes contamination in a cold-smoked rainbow trout processing plant detected by pulsed-field gel electrophoresis typing.sites of listeria monocytogenes contamination in a cold-smoked rainbow trout (oncorhynchus mykiss) processing plant were detected by sampling the production line, environment, and fish at different production stages. two lots were monitored. the frequency of raw fish samples containing l. monocytogenes was low. during processing, the frequency of fish contaminated with l. monocytogenes clearly rose after brining, and the most contaminated sites of the processing plant were the brining and postbr ...19999872773
bacterial resistance to ultrasonic waves under pressure at nonlethal (manosonication) and lethal (manothermosonication) temperatures.the decimal reduction times of streptococcus faecium, listeria monocytogenes, salmonella enteritidis, and aeromonas hydrophila corresponding to heat treatment at 62 degrees c were 7.1, 0.34, 0.024, and 0.0096 min, and those corresponding to manosonication treatment (40 degrees c, 200 kpa, 117 microm) were 4.0, 1.5, 0.86, and 0.90 min, respectively. the manosonication decimal reduction times of the four species investigated decreased sixfold when the amplitude was increased from 62 to 150 microm ...19999872795
growth of listeria monocytogenes and yersinia enterocolitica on cooked modified-atmosphere-packaged poultry in the presence and absence of a naturally occurring microbiota.cooked poultry cuts were inoculated with five-strain composite mixtures of either listeria monocytogenes or yersinia enterocolitica (1,000 cfu/150-g piece), packaged in 44:56 co2-n2, and stored at 3.5, 6.5, or 10 degrees c for up to 5 weeks. both l. monocytogenes and y. enterocolitica grew under all test conditions. the presence of a naturally occurring microbiota did not influence the growth of either pathogen. addition of lactate with the shelf life extender alta 2341 lengthened the lag phases ...19999872806
nosocomial listeria gastroenteritis in a newborn, confirmed by random amplification of polymorphic dna. 200011284931
[listeriosis: an infrequent infection in patients with hiv].although resistance to listeria monocytogenes infection requires intact t-cell mediated immunity, listeriosis is an infrequent problem in patients with hiv infection and only about 50 patients have been reported to date. only two patients with hiv and l. monocytogenes have been attended in our hospital since the beginning of aids epidemic in 1981. case 1: a man with hiv and 364 cd4+ cells/mm3 presented fever and occipital headache. the cerebral scan was normal and l. monocytogenes grew in licuor ...200011213581
[autoregulation of expression of secreted proteins in listeria monocytogenes].the spectrum of proteins secreted by l. monocytogenes greatly depends on the composition of the cultivation medium. the introduction of activated charcoal (ac) into brain heart infusion (bhi) leads to the secretion of a number of additional proteins with mol.wt. ranging between 20 and 100 kd, whose production is not observed in pure bhi. the effect depends on the absorption capacity of ac: when adsorption capacity is reduced due to a decrease in the concentration of ac or its preliminary saturat ...200011220960
[immunity in listeriosis].in this review modern concepts on the formation of specific immunity to listeriosis are presented. numerous data indicate that in listeria monocytogenes virulence and the capacity for inducing specific protection is ensured by the protein listeriolysin o. the importance of gamma-interferon, tumor necrosis factor alpha, interleukin 12 and other mediators in ensuring the differentiation of (cd4(+) t-cells into th1-helpers and cytotoxic t-lymphocytes in animals infected with l. monocytogenes is des ...200011220980
fresh ideas for food safety. 200011221672
laxp180, a mammalian acta-binding protein, identified with the yeast two-hybrid system, co-localizes with intracellular listeria monocytogenes.the listeria monocytogenes surface protein acta is an important virulence factor required for listerial intracellular movement by inducing actin polymerization. the only host cell protein known that directly interacts with acta is the phosphoprotein vasp, which binds to the central proline-rich repeat region of acta. to identify additional acta-binding proteins, we applied the yeast two-hybrid system to search for mouse proteins that interact with acta. a mouse cdna library was screened for acta ...200011207567
a novel function of inib from listeria monocytogenes: activation of nf-kappab in j774 macrophages.listeria monocytogenes causes a pro-inflammatory response on adhesion to macrophages. upregulation of inflammation genes involves the transcription factor nf-kappab. several components of l. monocytogenes, including lipoteichoic acid (lta), phospholipases and listeriolysin o (llo), have since been shown to mediate nf-kappab activation. here, we report that purified recombinant inlb, but not internalin (inla), is a potent activator of nf-kappab in the mouse macrophage-like cell line j774. express ...200011207569
the invasion protein inib from listeria monocytogenes activates plc-gamma1 downstream from pi 3-kinase.entry of the bacterial pathogen listeria monocytogenes into non-phagocytic mammalian cells is mainly mediated by the inlb protein. here we show that in the human epithelial cell line hep-2, the invasion protein inlb activates sequentially a p85beta-p110 class i(a) pi 3-kinase and the phospholipase c-gamma1 (plc-gamma1) without detectable tyrosine phosphorylation of plc-gamma1. purified inlb stimulates association of plc-gamma1 with one or more tyrosine-phosphorylated proteins, followed by a tran ...200011207601
listeriolysin o-induced stimulation of mucin exocytosis in polarized intestinal mucin-secreting cells: evidence for toxin recognition of membrane-associated lipids and subsequent toxin internalization through caveolae.lysteriolysin o (llo) induces a microtubule-dependent activation of mucin exocytosis in the human mucin-secreting ht29-mtx. cholesterol inhibits the llo-induced mucin exocytosis, whereas the oxidized form of cholesterol had no inhibitory effect. llo-induced mucin exocytosis inhibited by cholesterol can be restored by enzymatic treatment with cholesterol oxidase. inhibition of cholesterol synthesis in ht29-mtx cells results in a decrease in the llo-induced mucin exocytosis. other lipids such as g ...200011207603
[effect of cultivation temperature on nucleic acid level in bacteria listeria monocytogenes and yersinia pseudotuberculosis].the relationship between the multiplication of bacteria, the content of nucleic acid and the specific rate of their growth during their batch cultivation in nutrient broth and mineral medium at temperatures of 37 degrees c and 4-6 degrees c was studied in the causative agents of saprozoonotic infections with l. monocytogenes and y. pseudotuberculosis used as typical representatives of such bacteria. the content of dna was shown to remain practically unchanged after the alteration of cultivation ...200011210627
plasma cytokine response in mice with bacterial infection.exposure to microorganisms elicts the production of cytokines. these soluble factors enhance several innate immune functions and regulate the ensuing specific immune response aimed at limiting the spread of infection.200011200363
characterization by molecular cloning and sequencing of the gene encoding an aminopeptidase from listeria monocytogenes.the pepc gene of listeria monocytogenes encodes aminopeptidase c that is predicted to share 72% amino acid sequence similarity and 53% sequence identity with the cysteine aminopeptidase pepc from lactococcus lactis. the gene product also shows strong similarity to aminopeptidase c from streptococcus thermophilus and lactobacillus helveticus, and to a cysteine proteinase/bleomycin hydrolase from saccharomyces cerevisiae. the enzyme from l. monocytogenes displayed broad n-terminal hydrolytic activ ...200011204766
[infectious and metabolic nervous system complications of systemic cancer].to review the incidence and causes of the infections and metabolic diseases of the nervous system in patients with systemic neoplasias.200011205570
in vitro activities of 22 antimicrobial agents against listeria monocytogenes strains isolated in barcelona, spain. the collaborative study group of listeriosis of barcelona.the in vitro activity of 22 antimicrobial agents against 82 human listeria monocytogenes strains isolated in barcelona from 1994 to 1998 was determined. ampicillin and gentamicin showed good in vitro activity against all strains (mic90: 1 and < or = 0.25 microg/ml, respectively). no resistance to rifampin or co-trimoxazole was detected and only one strain was resistant to tetracycline. of the nine fluoroquinolones tested, clinafloxacin and gemifloxacin were the most active compounds (mic90: 0.12 ...200011146253
secretion of different listeriolysin cognates by recombinant attenuated salmonella typhimurium: superior efficacy of haemolytic over non-haemolytic constructs after oral vaccination.viable antigen (ag) delivery systems expressing defined pathogen-derived proteins represent powerful candidates for future vaccination strategies. here, recombinant (r)salmonella typhimurium aroa strains secreting listeriolysin (hly) of listeria monocytogenes in haemolytic or non-haemolytic form were constructed to direct these carriers into cytosolic or phagosomal host cell compartments, respectively. oral and intravenous (i.v.) vaccination of mice with either construct induced 'transporter ass ...200011165923
[quantitative risk assessment related to microbial food contamination].the four keystones of quantitative risk assessment are hazard identification, exposure assessment, dose-response assessment and risk characterization. this paper considers the different steps of risk assessment and their application to food microbiology. traditionally, quantitative risk assessment has been viewed simply as a method to estimate risk. however, when we conduct a complete risk assessment including different factors from "farm to fork" it can serve to understand the risk process. qua ...200011183481
microbiology. listeria enlists host in its attack. 200011184728
multistate outbreak of listeriosis--united states, 2000.since may 2000, 29 illnesses caused by a strain of listeria monocytogenes (lm) have been identified in 10 states: new york (15 cases); georgia (three); connecticut, ohio, and michigan (two each); and california, pennsylvania, tennessee, utah, and wisconsin (one each). dates of lm isolation ranged from may 17 through november 26 with 26 (90%) infections occurring since july 15. when subtyped, the lm isolates from these cases were indistinguishable by pulsed-field gel electrophoresis (pulsenet pat ...200011190115
control of foodborne pathogens during sufu fermentation and aging.control of the foodborne pathogens escherichia coli o157:h7, salmonella typhimurium, staphylococcus aureus, and listeria monocytogenes during sufu fermentation was evaluated. before fermentation, pathogens were inoculated onto tofu (substrate for sufu) at 5 log cfu/g or 3 log cfu/g, and starter culture (actinomucor elegans) was inoculated at 3 log cfu/g. after 2 days of fermentation at 30 degrees c, the four pathogens reached 7 to 9 log cfu/g, and the mold count reached 6 to 7 log cfu/g. after f ...200011192025
[use of poly-beta-oxybutyric acid by yersinia pseudotuberculosis and listeria monocytegenes bacteria at various temperatures].a comparative investigation of the intracellular content of poly-beta-hydroxybutyric acid showed that yersinia pseudotuberculosis strains accumulated, on the average, lower amounts of this reserve substance than listeria monocytogenes strains. the intracellular pool of poly-beta-hydroxybutyric acid was responsible for the growth of the bacteria at low temperatures (4-6 degrees c) in the absence of any exogenous carbon and energy source.200011195574
secrets of actin-based motility revealed by a bacterial pathogen.actin-based cell motility is a complex process involving a dynamic, self-organizing cellular system. experimental problems initially limited our understanding of this type of motility, but the use of a model system derived from a bacterial pathogen has led to a breakthrough. now, all the molecular components necessary for dynamic actin self-organization and motility have been identified, setting the stage for future mechanistic studies.200011253363
[urinary retention as the first sign of rhombencephalitis due to listeria monocytogenes]. 200011244698
use of the molecular typing methods to evaluate the control of listeria monocytogenes contamination in a raw milk and dairy products.nineteen serogroup 1/2a listeria monocytogenes strains isolated from raw milk, dairy products and salt water in one dairy were analyzed. pulsed field gel electrophoresis (pfge) and ribotyping were used to determine whether these strains isolated over a 8-month period are epidemiologically related. the samples of raw milk were contaminated by different l. monocytogenes clones. the clones isolated from dairy products (with the exception of one sample) and salt water were identical. comparative gen ...200011271825
post-transplant epididymitis and orchitis following listeria monocytogenes septicaemia.we report the occurrence of epididymitis and orchitis 1 week after the onset of listeriosis in an 11-month-old boy receiving an orthotopic liver transplantation for biliary atresia. immunologic implications of listeria monocytogenes-induced testicular inflammation are discussed, and the potential role of immunosuppression with tacrolimus is also discussed.200011272610
the main cold shock protein of listeria monocytogenes belongs to the family of ferritin-like proteins.the transfer of the food-borne pathogen listeria monocytogenes from 30 to 5 degrees c was characterized by the sharp induction of a low molecular mass protein. this major cold shock protein has an isoelectric point at ph 5.1 and a molecular mass of about 18 kda, as observed on two-dimensional gel electrophoresis (2-de) pattern. its n-terminal sequence, obtained from the 2-de spot, shared a complete sequence identity with a listeria innocua non-heme iron-binding ferritin. the purification of thes ...200010981685
persistent listeria monocytogenes strains show enhanced adherence to food contact surface after short contact times.adherence of 3 persistent and 14 nonpersistent listeria monocytogenes strains to stainless steel surfaces after short and long contact times was investigated. l. monocytogenes strains were obtained from poultry plants and an ice cream plant throughout several years. adherence tests were performed in tryptic soy broth at 25 degrees c for 1, 2, and 72 h. test surfaces were rinsed after the contact time, and attached cells were stained with acridine orange and enumerated with an epifluorescence mic ...200010983793
incidence and seasonal variation of listeria species in bulk tank goat's milk.four hundred and fifty raw goat's milk samples obtained from the bulk tanks of 39 goat farms were analyzed for listeria spp. over a 1-year period. modified versions of the u.s. department of agriculture food safety and inspection service (usda-fsis) and food and drug administration (fda) protocols were used for recovery of listeria. overall, 35 (7.8%) samples yielded listeria spp. with listeria monocytogenes identified in 17 of the 35 (3.8%) listeria-positive samples. listeria innocua was detect ...200010983794
use of oleic acid to reduce the population of the bacterial flora of poultry skin.the effect of oleic acid on native bacterial flora of poultry skin was examined. skin from commercial broiler carcasses was washed once or twice in solutions of 0, 2, 4, 6, 8, or 10% (wt/vol) oleic acid and rinsed in peptone water. aerobic bacteria, enterobacteriaceae, campylobacter, and enterococci in the rinsates were enumerated. significantly fewer aerobic bacteria, enterobacteriaceae, campylobacter, and enterococci were recovered from rinsates of skin washed in oleic acid than from control s ...200010983807
myosin light chain kinase plays an essential role in s. flexneri dissemination.shigella flexneri, the causitive agent of bacillary dysentery, has been shown to disseminate in colonic epithelial cells via protrusions that extend from infected cells and are endocytosed by adjacent cells. this phenomenon occurs in the region of the eukaryotic cell's adherens junctions and is inhibited by pharmacological reagents or host cell mutations that completely disrupt the junctional complex. in this study, inhibitors of the myosin light chain kinase (mlck) were shown to dramatically de ...200010984429
[epidemiology of human listeria infections in france].human listeriosis is a relatively rare but serious disease with case fatality rates between 20 and 30%. the majority of patients who have listeriosis present with meningitis or septicaemia. listeriosis during pregnancy can lead to a congenital infection, neonatal sepsis and meningitis or foetal death. the main mode of transmission is through contaminated foods. the infection usually occurs sporadically but small outbreaks and even large epidemics have occurred in a large number of industrialised ...200010989536
[prevention of listeria infections].listeriosis is a rare but very serious foodborne disease. the non-contamination of food products is the best prevention of listeriosis. in spite of notable efforts to improve the microbiologic quality of food products through surveillance and control of food contaminations, the prevention has still to be based upon the information of consumers. this information can take different forms. when a food product is found to be contaminated with listeria monocytogenes, if the withdrawal of this product ...200010989539
dual epitope recognition by the vasp evh1 domain modulates polyproline ligand specificity and binding affinity.the ena-vasp family of proteins act as molecular adaptors linking the cytoskeletal system to signal transduction pathways. their n-terminal evh1 domains use groups of exposed aromatic residues to specifically recognize 'fpppp' motifs found in the mammalian zyxin and vinculin proteins, and acta protein of the intracellular bacterium listeria monocytogenes. here, evidence is provided that the affinities of these evh1-peptide interactions are strongly dependent on the recognition of residues flanki ...200010990454
activation of host phospholipases c and d in macrophages after infection with listeria monocytogenes.infection of the j774 murine macrophage-derived cell line with listeria monocytogenes results in several elevations of intracellular calcium during the first 15 min of infection. these appear to result from the actions of secreted bacterial proteins, including phosphatidylinositol-specific phospholipase c (pi-plc), a broad-range phospholipase c, and listeriolysin o (llo) (s. j. wadsworth and h. goldfine, infect. immun. 67:1770-1778, 1999). we have measured hydrolysis of host pi and the activatio ...200010992479
presence of bacterial 16s ribosomal rna gene segments in human intestinal lymph follicles.there is currently no information regarding microbial agents inside the intestinal lymph follicles.200010994621
vidas enzyme-linked immunoflourescent assay for detection of listeria in foods: collaborative study.the vidas lis method and the traditional culture methods for detection of listeria species in food were evaluated in a multilaboratory comparative study. the 6 foods tested were either naturally contaminated or inoculated with 3 different concentrations of listeria. results for each food and each contamination level with the vidas lis method were as good as or better than those obtained with the traditional culture method. of 1558 samples tested, 935 were positive: 839 by the vidas method and 80 ...200010995115
insertional knock-out of protein translocation systems common for yersinia enterocolitica and listeria monocytogenes.to carry out efficient insertional mutagenesis in listeria monocytogenes and to facilitate the characterisation of disrupted genes, a novel derivative of plasmid pacyc 184 was constructed, pliv vira3, carrying a fragment from the vira region of the of y. enterocolitica plasmid pyve 0:9. after transformation of this plasmid into l. monocytogenes it was possible to select for its integration into the host dna at 42 degrees c. insertional mutants of l. monocytogenes obtained by using pliv vector co ...200010997489
comparative genomics of the late gene cluster from lactobacillus phages.three prophage sequences were identified in the lactobacillus johnsoni strain ncc533. prophage lj965 predicted a gene map very similar to those of pac-site streptococcus thermophilus phages over its dna packaging and head and tail morphogenesis modules. sequence similarity linked the putative dna packaging and head morphogenesis genes at the protein level. prophage lj965/s. thermophilus phage sfi11/lactococcus lactis phage tp901-1 on one hand and lactobacillus delbrueckii phage ll-h/lactobacillu ...200010998330
delivery of protein antigens and dna by virulence-attenuated strains of salmonella typhimurium and listeria monocytogenes.two different plasmid-vector systems were developed which allow the efficient production and presentation of protein antigens in antigen-presenting cells (apc) by means of virulence-attenuated bacteria. the first antigen-delivery system is based on the secretion machinery of the escherichia coli hemolysin (hlya-type i secretion system), which transports proteins, possessing the specific hlya secretion signal (hlya(s)) at the c-terminus, across both membranes of gram-negative bacteria. this syste ...200011000455
cloning, sequence analysis, and expression of lactobacillus casei phage pl-1 lysis genes.the genes encoding the host cell wall-lytic proteins were searched in the genome dna of phage pl-1 active against lactobacillus casei atcc 27092 by comparing the amino acid sequences with those of others using a computer software of the ddbj data base. the gene regions found were cloned into e. coli by inserting pcr-amplified dna fragments into the ecori site of puc 19, and the nucleotide sequences were determined. one of the orfs (hol) consisted of 270 bp encoding 90 amino acids. the hol produc ...200011003466
identification in listeria monocytogenes of meca, a homologue of the bacillus subtilis competence regulatory protein.we identified in listeria monocytogenes a gene encoding a protein homologous to meca, a regulatory protein acting with clpc and comk in the competence pathway of bacillus subtilis. in l. monocytogenes, meca is involved, along with clpc and clpp, in the downregulation of a 64-kda secreted protein. in b. subtilis, the meca protein of l. monocytogenes behaves as a regulatory protein, controlling the transcription of comk and comg. complete or disrupted comk homologues were also found in l. monocyto ...200011004200
bacterial penetration across the blood-brain barrier during the development of neonatal meningitis.bacterial pathogens may breach the blood-brain barrier (bbb) and invade the central nervous system through paracellular and/or transcellular mechanisms. transcellular penetration, e.g., transcytosis across the bbb has been demonstrated for escherichia coli k1, group b streptococcus, listeria monocytogenes, citrobacter freundii and streptococcus pneumonia strains. genes contributing to invasion of brain microvascular endothelial cells include e. coli k1 genes ompa, ibea, ibeb, and yijp. understan ...200011008113
interleukin-18 (il-18) and infectious diseases, with special emphasis on diseases induced by intracellular pathogens.interleukin-18 (il-18) is a novel cytokine mainly produced by activated macrophages. il-18 was originally called interferon-gamma inducing factor, due to its action in inducing ifn-gamma secretion from th1 cells, nk cells and nkt cells. it has been reported that il-18 may play important roles in various diseases including cancer and infectious diseases. this review deals with the roles of il-18 in infectious diseases, with special emphasis on il-18 in infectious diseases caused by intracellular ...200011008115
application of 5'-nuclease pcr for quantitative detection of listeria monocytogenes in pure cultures, water, skim milk, and unpasteurized whole milk.pcr techniques have significantly improved the detection and identification of bacterial pathogens. countless adaptations and applications have been described, including quantitative pcr and the latest innovation, real-time pcr. in real-time pcr, e.g., the 5'-nuclease chemistry renders the automated and direct detection and quantification of pcr products possible (p. m. holland et al., proc. natl. acad. sci. usa 88:7276-7280, 1991). we present an assay for the quantitative detection of listeria ...200011010869
use of two-dimensional electrophoresis to study differential protein expression in divercin v41-resistant and wild-type strains of listeria monocytogenes.the use of bacteriocins from food-grade lactic acid bacteria to fight against the food-borne pathogen listeria monocytogenes has been gaining interest. however, the emergence of resistant cells is frequently reported when listeria is exposed to such antibacterials. a two-dimensional electrophoresis study of whole-cell protein expression of listeria monocytogenes variants sensitive or resistant to the action of a bacteriocin produced by carnobacterium divergens v41, divercin v41, is reported in t ...200011010876
cold shock induction of thermal sensitivity in listeria monocytogenes.cold shock at 0 to 15 degrees c for 1 to 3 h increased the thermal sensitivity of listeria monocytogenes. in a model broth system, thermal death time at 60 degrees c was reduced by up to 45% after l. monocytogenes scott a was cold shocked for 3 h. the duration of the cold shock affected thermal tolerance more than did the magnitude of the temperature downshift. the z values were 8.8 degrees c for controls and 7.7 degrees c for cold-shocked cells. the d values of cold-shocked cells did not return ...200011010880
cold shock and its effect on ribosomes and thermal tolerance in listeria monocytogenes.differential scanning calorimetry (dsc) and fatty acid analysis were used to determine how cold shocking reduces the thermal stability of listeria monocytogenes. additionally, antibiotics that can elicit production of cold or heat shock proteins were used to determine the effect of translation blockage on ribosome thermal stability. fatty acid profiles showed no significant variations as a result of cold shock, indicating that changes in membrane fatty acids were not responsible for the cold sho ...200011010881
improved template preparation for pcr-based assays for detection of food-borne bacterial pathogens.shigella flexneri, salmonella enterica serotype typhimurium, and listeria monocytogenes were applied to fta filters, and the filters were used directly as templates to demonstrate their sensitivity and applicability in pcr-based detection assays. with pure cultures, the sensitivities of detection by fta filter-based pcr were 30 to 50 and 200 cfu for the gram-negative enterics and listeria, respectively. different numbers of s. flexneri cells were used in controlled contamination experiments with ...200011010913
the contribution of both oxygen and nitrogen intermediates to the intracellular killing mechanisms of c1q-opsonized listeria monocytogenes by the macrophage-like ic-21 cell line.listeria monocytogenes is a facultative intracellular pathogen which is internalized by host mammalian cells upon binding to their surface. further listerial growth occurs in the cytosol after escape from the phagosomal-endosomal compartment. we have previously reported that c1q is able to potentiate l. monocytogenes phagocytosis upon bacterial opsonization by ingestion through c1q-binding structures. in this report, we analysed the post-phagocytic events upon internalization of c1q-opsonized l. ...200011012757
interactions of high hydrostatic pressure, pressurization temperature and ph on death and injury of pressure-resistant and pressure-sensitive strains of foodborne pathogens.the objective of this study is to determine the interactions between high hydrostatic pressure, pressurization temperature, time and ph during pressurization on death and injury of pressure-resistant and pressure-sensitive strains of four foodborne pathogens: staphylococcus aureus 485 and 765, listeria ,monocytogenes ca and oh2, escherichia coli o157:h7 933 and 931, salmonella enteritidis fda and salmonella typhimurium e21274. among these strains s. aureus 485, l. monocytogenes ca, e. coli o157: ...200011014520
subchronic silica exposure enhances respiratory defense mechanisms and the pulmonary clearance of listeria monocytogenes in rats.both listeria monocytogenes infection and silica exposure have been shown to significantly alter immune responses. in this study, we evaluated the effect of preexposure to silica on lung defense mechanisms using a rat pulmonary l. monocytogenes infection model. male sprague-dawley rats were instilled intratracheally with saline (vehicle control) or silica using either an acute treatment regimen (5 mg/kg; 3 days) or a subchronic treatment protocol (80 mg/kg; 35 days). at 3 or 35 days after silica ...200011015141
absence of serotype-specific surface antigen and altered teichoic acid glycosylation among epidemic-associated strains of listeria monocytogenes.outbreaks of food-borne listeriosis have often involved strains of serotype 4b. examination of multiple isolates from three different outbreaks revealed that ca. 11 to 29% of each epidemic population consisted of strains which were negative with the serotype-specific monoclonal antibody c74.22, lacked galactose from the teichoic acid of the cell wall, and were resistant to the serotype 4b-specific phage 2671.200011015420
interferon gamma signaling alters the function of t helper type 1 cells.one mechanism regulating the ability of different subsets of t helper (th) cells to respond to cytokines is the differential expression of cytokine receptors. for example, th2 cells express both chains of the interferon gamma receptor (ifn-gammar), whereas th1 cells do not express the second chain of the ifn-gammar (ifn-gammar2) and are therefore unresponsive to ifn-gamma. to determine whether the regulation of ifn-gammar2 expression, and therefore ifn-gamma responsiveness, is important for the ...200011015439
analysis of the role of the listeria monocytogenes f0f1 -atpase operon in the acid tolerance response.as little is known about the genes involved in the induction of an acid tolerance response in listeria monocytogenes, the role of the f0f1-atpase was analyzed as a consequence of its role in the acid tolerance of a number of other bacteria and its conserved nature. it was found that acid adapted cells treated with n,n'-dicyclohexylcarbodiimide (dccd) exhibited greatly enhanced sensitivity to low ph stress. degenerate primers were designed to amplify and sequence a portion of the atpd gene. subse ...200011016603
new developments in chromogenic and fluorogenic culture media.this review describes some recent developments in chromogenic and fluorogenic culture media in microbiological diagnostic. the detection of beta-d-glucuronidase (gud) activity for enumeration of escherichia coli is well known. e. coli o157:h7 strains are usually gud-negative and do not ferment sorbitol. these characteristics are used in selective media for these organisms and new chromogenic media are available. some of the new chromogenic media make the salmonella diagnostic easier and faster. ...200011016610
analysis of the role of betl in contributing to the growth and survival of listeria monocytogenes lo28.survival of the food-borne pathogen listeria monocytogenes in environments of elevated osmolarity and reduced temperature is attributed, at least in part, to the accumulation of the trimethylammonium compound glycine betaine. previously we identified betl, a gene encoding the secondary glycine betaine transporter betl, which we linked to the salt tolerance of listeria. in this report, we demonstrate that betl, preceded by a consensus sigmab-dependent promoter, is regulated by osmotic up-shock, a ...200011016615
foodborne listeriosis.listeria monocytogenes emerged as an important foodborne pathogen in the latter part of the 20th century. clinical syndromes caused by this microorganism include sepsis in the immunocompromised patient, meningoencephalitis in infants and adults, and febrile gastroenteritis. focal infections at other sites are less frequent. listeria species are commonly found in raw and unprocessed food products. major outbreaks of listeriosis, with high morbidity and mortality, have been caused by a variety of ...200011017828
polymerase chain reaction for the laboratory diagnosis of aseptic meningitis and encephalitis.a protocol for testing cerebrospinal fluid specimens using a range of pcr assays for the diagnosis of central nervous system infection was developed and used to test prospectively 383 specimens. pcr assays were used for the detection of adenovirus, borrelia burgdorferi, enteroviruses, epstein barr virus, cytomegalovirus, herpes simplex virus, human herpes virus type 6, jc virus, leptospira interrogans, listeria monocytogenes, lymphocytic choriomeningitis virus, measles virus, mumps virus, mycoba ...200011018820
predictions of growth for listeria monocytogenes and salmonella during fluctuating temperature.we studied the predictive performance of a dynamic modelling approach, combined with predictions from the food micromodel software, applied to the growth of listeria monocytogenes and salmonella in pasteurised milk, chicken liver pâté and minced chicken, under constant as well as fluctuating temperatures. we found that, in general, the accuracy of a prediction under fluctuation temperature was similar to that under constant temperature. generally, there was a good agreement between predictions a ...200011020037
structural model requirements to describe microbial inactivation during a mild heat treatment.the classical concept of d and z values, established for sterilisation processes, is unable to deal with the typical non-loglinear behaviour of survivor curves occurring during the mild heat treatment of sous vide or cook-chill food products. structural model requirements are formulated, eliminating immediately some candidate model types. promising modelling approaches are thoroughly analysed and, if applicable, adapted to the specific needs: two models developed by casolari (1988), the inactiva ...200011020040
comparison between the growth of yersinia enterocolitica, listeria monocytogenes, escherichia coli o157:h7 and salmonella spp. in ground beef packed by three commercially used packaging techniques.growth of the pathogens yersinia enterocolitica, listeria monocytogenes, escherichia coli o157:h7 and strains of salmonella were compared in ground beef packed in modified atmospheres of 60% co2/40% n2/0.4% co (high co2/low co mixture), 70% o2/30% co2 (high o2 mixture) and in chub packs (stuffed in plastic casings). the ground beef was inoculated with rifampicin-resistant or nalidixic acid/streptomycin-resistant strains of the pathogens (final concentration 10(2) - 10(3) bacteria/g) and stored a ...200011020041
cloning, sequencing and characterisation of a listeria monocytogenes gene encoding a fibronectin-binding protein.listeria monocytogenes is a gram-positive, non-sporulating food-borne pathogen of man and animals that is able to invade many eukaryotic cells. l. monocytogenes possesses several proteins that bind fibronectin. in this study, an l. monocytogenes dna library in puc19 was screened with fibronectin and a gene encoding a 24.6-kda fibronectin-binding protein (fbp) was isolated and sequenced. transcripts of the fbp gene were found in wild-type, in deltaprfa, and prfa-s183a strains, despite the presenc ...200011023185
induction of human immunodeficiency virus (hiv)-specific cd8 t-cell responses by listeria monocytogenes and a hyperattenuated listeria strain engineered to express hiv antigens.induction of cell-mediated immunity may be essential for an effective aids vaccine. listeria monocytogenes is an attractive bacterial vector to elicit t-cell immunity to human immunodeficiency virus (hiv) because it specifically infects monocytes, key antigen-presenting cells, and because natural infection originates at the mucosa. immunization with recombinant l. monocytogenes has been shown to protect mice from lymphocytic choriomeningitis virus, influenza virus, and tumor inoculation. l. mono ...200011024127
neurolisteriosis presenting as recurrent transient ischemic attacks.an elderly man experienced recurrent transient episodes of right arm weakness and expressive aphasia. he was initially treated with aspirin and then with coumadin. thirteen days after initial presentation, he became febrile and had signs of meningitis. the illness progressed relentlessly to death 9 weeks after admission to the hospital. necropsy showed prominent meningitis with vasculitis extending into the left frontal lobe. polymerase chain reaction identified the organism as listeria monocyto ...200011026451
application of polynomial models to predict growth of mixed cultures of pseudomonas spp. and listeria in meat.three models for one rapid and one slow growing strain of pseudomonas fragi and one slow growing strain of p. fluorescens were developed in a meat broth; they were designed to take account of variations in growth and to provide a growth response interval. these models, and another for listeria monocytogenes (lm14 model), were used to predict the growth of spoilage pseudomonas spp. and pathogenic listeria in meat products. the pseudomonas and listeria models provided satisfactory predictions conc ...200011028957
maillard reaction causes suppression of virulence gene expression in listeria monocytogenes.many environmental signals affect the expression of virulence genes of the food borne pathogen listeria monocytogenes. in addition media composition has been shown to suppress levels of haemolytic activity. using a pr(plca)::luxab reporter gene fusion it was observed that the heat processing of media also reduces the level of virulence gene expression in l. monocytogenes without affecting its growth. physicochemical factors that are considered to enhance the maillard reaction were also found to ...200011028958
Refresh
firstprev
...61626364656667686970...
nextlast
Displaying items 6101 - 6200 of 16792