Publications

detection and characterization of the novel bacteriocin entomocin 9, and safety evaluation of its producer, bacillus thuringiensis ssp. entomocidus hd9.	to identify and characterize new bacteriocins from a collection of 41 strains belonging to 27 subspecies of bacillus thuringiensis, and to evaluate the safety of the producers.	2003	14633027
production of antibacterial substances by bifidobacterial isolates from infant stool active against listeria monocytogenes.	this study aimed to characterize new isolates of human bifidobacteria, evaluate some of their probiotic potential and to screen these isolates for their effectiveness at inhibiting listeria monocytogenes in vitro.	2003	14633035
inactivation of escherichia coli o157:h7, salmonella enteritidis and listeria monocytogenes on the surface of tomatoes by neutral electrolyzed water.	to determine the efficacy of neutral electrolyzed water (new) in killing escherichia coli o157:h7, salmonella enteritidis and listeria monocytogenes, as well as nonpathogenic e. coli, on the surface of tomatoes, and to evaluate the effect of rinsing with new on the organoleptic characteristics of the tomatoes.	2003	14633103
presence of listeria and salmonella spp. in retail chicken in northern ireland.	retail packs of fresh chicken in northern ireland were sampled to determine the frequency with which they were contaminated with salmonella and listeria spp.	2003	14633115
promiscuity of mhc class ib-restricted t cell responses.	murine infection with the gram-positive intracellular bacterium listeria monocytogenes activates cd8(+) t cells that recognize bacterially derived n-formyl methionine peptides in the context of h2-m3 mhc class ib molecules. three peptides, fmigwii, fmivil, and fmivtlf, are targets of l. monocytogenes-specific cd8(+) t cells. to investigate epitope cross-recognition by h2-m3-restricted cd8(+) t cells, we deleted the sequence encoding fmigwii from a virulent strain of l. monocytogenes. infection w ...	2003	14634106
activation of antigen-specific cd8 t cells results in minimal killing of bystander bacteria.	memory cd8 t cells play a critical role in protective immunity against intracellular pathogens. in addition to their ability to specifically recognize and lyse infected targets, activated cd8 t cells secrete cytokines that induce phagocytic cells to engulf and kill bacterial pathogens. in this study, we asked whether activation of ag-specific cd8 t cells results in nonspecific killing of bystander bacteria during a mixed infection. mice with epitope-specific memory cd8 t cells were coinfected wi ...	2003	14634115
listeria species escape from the phagosomes of interleukin-4-deactivated human macrophages independent of listeriolysin.	listeria monocytogenes is the causative agent of infections like sepsis and meningitis, especially in immunocompromised hosts. human macrophages are able to phagocytose and digest l. monocytogenes but il-4 prevents human macrophages from killing the bacteria, the mechanisms of which are unknown. in the present study, we examined various listeria species and strains including wild-type and deletion mutants in human macrophages pretreated with il-4. to analyse the il-4-mediated deactivation proces ...	2003	14636240
a three-tiered approach to differentiate listeria monocytogenes biofilm-forming abilities.	the purpose of this research was to develop a system for cultivating and evaluating listeria monocytogenes biofilms that produces consistent and reliable results. a three-tiered approach was used to evaluate biofilm-forming abilities of three l. monocytogenes strains that were originally associated with listeriosis outbreaks. a l. monocytogenes 'honeycomb' biofilm structure was described. l. monocytogenes strains scott a and v7 were comparable in developing biofilm network structures and f2365 w ...	2003	14638425
the listeria monocytogenes lema gene product is not required for intracellular infection or to activate fmigwii-specific t cells.	clearance of the intracellular bacterial pathogen listeria monocytogenes requires antigen-specific cd8(+) t cells. recently it was shown that activation of class ib major histocompatibility complex (mhc)-restricted cd8(+) t cells alone is sufficient for immune protection against listeriae. a major component of the class ib mhc-restricted t-cell response is t cells that recognize formylated peptide antigens presented by m3 molecules. although three n-formylated peptides derived from l. monocytoge ...	2003	14638756
listeria monocytogenes mutants that fail to compartmentalize listerolysin o activity are cytotoxic, avirulent, and unable to evade host extracellular defenses.	listeria monocytogenes is a facultative intracellular bacterial pathogen that escapes from a phagosome and grows in the host cell cytosol. escape of the bacterium from the phagosome to the cytosol is mediated by the bacterial pore-forming protein listeriolysin o (llo). llo has multiple mechanisms that optimize activity in the phagosome and minimize activity in the host cytosol. mutants that fail to compartmentalize llo activity are cytotoxic and have reduced virulence. we sought to determine why ...	2003	14638761
characterization of an extracellular virulence factor made by group a streptococcus with homology to the listeria monocytogenes internalin family of proteins.	leucine-rich repeats (lrr) characterize a diverse array of proteins and function to provide a versatile framework for protein-protein interactions. importantly, each of the bacterial lrr proteins that have been well described, including those of listeria monocytogenes, yersinia pestis, and shigella flexneri, have been implicated in virulence. here we describe an 87.4-kda group a streptococcus (gas) protein (designated slr, for streptococcal leucine-rich) containing 10 1/2 sequential units of a 2 ...	2003	14638794
drosophila s2 cells: an alternative infection model for listeria monocytogenes.	listeria monocytogenes is a gram-positive facultative intracellular bacterial pathogen that infects humans and animals. its pathogenic strategy involves the expression of virulence proteins that mediate intracytosolic growth and cell-to-cell spread. a key virulence protein is the cholesterol-dependent cytolysin, listeriolysin o (llo), which is largely responsible for mediating escape from the phagosome into the host cytosol. to study further the host processes exploited during l. monocytogenes i ...	2003	14641173
exploration of host-pathogen interactions using listeria monocytogenes and drosophila melanogaster.	the facultative intracellular bacterial pathogen listeria monocytogenes is capable of replicating within a broad range of host cell types and host species. we report here the establishment of the fruit fly drosophila melanogaster as a new model host for the exploration of l. monocytogenes pathogenesis and host response to infection. listeria monocytogenes was capable of establishing lethal infections in adult fruit flies and larvae with extensive bacterial replication occurring before host death ...	2003	14641175
immunomodulation by yersinia enterocolitica: comparison of live and heat-killed bacteria.	this study compared the immunomodulating properties of viable and killed yersinia enterocolitica o9 in balb/c mice. at 10 days after infection by the intragastric route, ex vivo assays showed a suppression of spleen cell proliferation in response to salmonella lipopolysaccharide, concanavalin a and heat-killed yersiniae. mice infected with y. enterocolitica o9 for 10 days resisted the challenge with a lethal dose of listeria monocytogenes. in contrast, intravenous administration of heat-killed y ...	2003	14642307
immobilized enzyme-linked dna-hybridization assay with electrochemical detection for cryptosporidium parvum hsp70 mrna.	an electrochemical enzyme-linked immobilized dna-hybridization assay for the detection of cryptosporidium parvum in water has been developed. the target molecule was a 121-nucleotide sequence from the c. parvum heat shock protein 70 (hsp70 mrna from u71181 gene). this analyte offers the possibility of distinguishing dead from live oocysts. the assay involves covalent attachment of a primary dna probe via its 5'-amine-terminus to self-assembled monolayers of mercaptoundecanoic acid to a gold surf ...	2003	14572058
antibacterial activities of phenolic benzaldehydes and benzoic acids against campylobacter jejuni, escherichia coli, listeria monocytogenes, and salmonella enterica.	we evaluated the bactericidal activities of 35 benzaldehydes, 34 benzoic acids, and 1 benzoic acid methyl ester against campylobacter jejuni, escherichia coli o157:h7, listeria monocytogenes, and salmonella enterica when these compounds were substituted on the benzene ring with 0, 1, 2, or 3 hydroxy (oh) and/or methoxy (och3) groups in a ph 7.0 buffer. dose-response plots were used to determine the percentage of the sample that induced a 50% decrease in cfu after 60 min (ba50). of the 70 compoun ...	2003	14572218
prevalence of listeria monocytogenes in, and microbiological and sensory quality of, rainbow trout, whitefish, and vendace roes from finnish retail markets.	the prevalence of listeria monocytogenes in retail roe, as well as the microbiological and sensory qualities of the roe, were studied for three fish species under three different storage conditions. a total of 147 finnish rainbow trout (oncorhynchus mykiss), whitefish (coregonus lavaretus), vendace (coregonus albula), and burbot (lota lota) roe samples were bought fresh, frozen, or frozen-thawed from finnish retail markets. the overall prevalence of l. monocytogenes was 5%; however, the prevalen ...	2003	14572220
survival of listeria monocytogenes in a simulated recirculating brine chiller system.	contamination by listeria monocytogenes of processed meats after cooking presents a significant food safety risk. the purpose of this study was to determine the survival of l. monocytogenes in a simulated recirculating brine chiller system using ph values of 5, 6, and 7 with free chlorine concentrations of 0, 3, 5, and 10 ppm in 20% salt brine at -12 degrees c. at ph values of 5, 6, and 7 with chlorine concentrations of 2 and 3 ppm, using 10(8) cfu in a test tube system, an immediate drop of 0.2 ...	2003	14572221
consumer food-handling behaviors associated with prevention of 13 foodborne illnesses.	to be effective in reducing the incidence of foodborne illness, consumers and food safety educators need information about behaviors that will decrease exposure to foodborne pathogens. a four-round delphi technique was used to survey nationally recognized experts in food microbiology, epidemiology, food safety education, and food safety policy with the aim of identifying and ranking food-handling and consumption behaviors associated with 13 major foodborne pathogens. the food safety experts rank ...	2003	14572229
validation of the usda/ars package rinse method for recovery of listeria monocytogenes from naturally contaminated, commercially prepared frankfurters.	the utility of the u.s. department of agriculture/agricultural research service (usda/ars) package rinse method for recovering listeria monocytogenes from the surface of contaminated foods was validated in comparison to the standard usda/food safety and inspection service (fsis) product composite enrichment method and two other methods using frankfurters from a lot with a known package prevalence rate of approximately 16% for this pathogen. one hundred packages from this batch of naturally conta ...	2003	14572233
dna vaccination protects mice against challenge with listeria monocytogenes expressing the hepatitis c virus ns3 protein.	the goal of this study was to develop a new surrogate challenge model for use in evaluating protective cell-mediated immune responses against hepatitis c virus (hcv) antigens. the use of recombinant listeria monocytogenes organisms which express hcv antigens provides novel tools with which to assay such in vivo protection, as expression of immunity against this hepatotropic bacterial pathogen is dependent on antigen-specific cd8(+) t lymphocytes. a plasmid dna vaccine encoding a ubiquitin-ns3 fu ...	2003	14573658
capg(-/-) mice have specific host defense defects that render them more susceptible than capg(+/+) mice to listeria monocytogenes infection but not to salmonella enterica serovar typhimurium infection.	loss of the actin filament capping protein capg has no apparent effect on the phenotype of mice maintained under sterile conditions; however, bone marrow-derived macrophages from capg(-/-) mice exhibited distinct motility defects. we examined the ability of capg(-/-) mice to clear two intracellular bacteria, listeria monocytogenes and salmonella enterica serovar typhimurium. the 50% lethal dose of listeria was 10-fold lower for capg(-/-) mice than for capg(+/+) mice (6 x 10(3) cfu for capg(-/-) ...	2003	14573680
cesrk, a two-component signal transduction system in listeria monocytogenes, responds to the presence of cell wall-acting antibiotics and affects beta-lactam resistance.	listeria monocytogenes is a food-borne pathogen that can cause a variety of illnesses ranging from gastroenteritis to life-threatening septicemia. the beta-lactam antibiotic ampicillin remains the drug of choice for the treatment of listeriosis. we have previously identified a response regulator of a putative two-component signal transduction system that plays a role in the virulence and ethanol tolerance of l. monocytogenes. here we present evidence that the response regulator, cesr, and a hist ...	2003	14576097
characterization and application of a listeria monocytogenes reactive monoclonal antibody c11e9 in a resonant mirror biosensor.	typical detection of listeria monocytogenes involves selective enrichment, isolation and biochemical testing. development of antibodies to listeria species has improved detection; however, most antibodies detect all species of listeria. a previously developed monoclonal antibody (mab)-c11e9 was examined for its reaction to 13 l. innocua and 40 l. monocytogenes strains representing all 13 serotypes by elisa. absorbance values for l. monocytogenes strains were 0.44-3.58 and for l. innocua 0.22-1.4 ...	2003	14580886
inhibition of listeria monocytogenes by bovicin hc5, a bacteriocin produced by streptococcus bovis hc5.	cattle can be infected with listeria monocytogenes by consuming contaminated plant materials, soil or silage, and farmers have sought ways of preventing this contamination. recent work indicated that streptococcus bovis hc5 produced a bacteriocin (bovicin hc5) that could inhibit a variety of gram-positive bacteria, and we examined the ability of bovicin hc5 to inhibit 10 strains of l. monocytogenes that had been isolated from plant materials, soil, silage and infected cattle. growth experiments ...	2003	14580975
antimicrobial resistance of listeria monocytogenes.	listeria monocytogenes is an opportunistic pathogen that causes rare but frequently fatal infections, termed listerioses. in general, strains of l. monocytogenes are susceptible to a wide range of antibiotics, except for the cephalosporins, fluorochinolones and fosfomycin (hof, 1991). the current therapy of choice is a combination of ampicillin and aminoglycoside, usually gentamicin (lorber, 1997). in cases when it is not possible to use a beta-lactam antibiotic, second-choice therapy involves t ...	2003	14594399
ampicillin resistance in listeria monocytogenes acquired as a result of transposon mutagenesis.	we have used plasmid pltv3, which carries transposon tn917, to obtain a series of mutants of listeria monocytogenes egd showing varied degrees of resistance to ampicillin and other beta-lactam antibiotics, including imipenem. in this paper we focus on the characteristics of two strains in which decreased susceptibility to ampicillin is accompanied by changes in the structure of the cell wall murein and cell-wall related changes of phenotype.	2003	14594400
wessex shopping basket survey - a structured approach to local food sampling.	the shopping basket approach to food sampling, in which ready-to-eat food items from a shopping list were sampled at premises chosen at random, was adopted by 15 environmental health departments in the wessex region. a total of 2037 samples were analysed over a 30-month period. the microbiological quality varied considerably between food categories, with gravy and stock samples giving the highest proportion of satisfactory results. sliced meats, cooked rice and sandwiches gave the poorest overal ...	2003	14594701
functionality of enterococci in dairy products.	enterococci have important implications in the dairy industry. they occur as nonstarter lactic acid bacteria (nslab) in a variety of cheeses, especially artisan cheeses produced in southern europe from raw or pasteurised milk, and in natural milk or whey starter cultures. they play an acknowledged role in the development of sensory characteristics during ripening of many cheeses and have been also used as components of cheese starter cultures. the positive influence of enterococci on cheese seem ...	2003	14596993
functionality of enterococci in meat products.	the presence of enterococci in meat fermentation is a constant as reported in the literature. despite the concern about pathogenicity of enterococci, recent studies point out that food and meat enterococci, especially enterococcus faecium have a much lower pathogenicity potential than clinical strains. enterococci possess a competitive advantage over other microbiota in meat fermentations, and many enterococci isolated from sausages have the ability to produce enterocins harbouring antimicrobial ...	2003	14596994
enterococcus faecium rzs c5, an interesting bacteriocin producer to be used as a co-culture in food fermentation.	enterocins, bacteriocins produced by enterococci, are gaining interest because of their industrial potential. due to its bacteriocin production, enterococcus faecium rzs c5, a natural cheese isolate, has a strong activity towards listeria monocytogenes. for this reason, the strain may be applicable as a bacteriocin-producing co-culture in food fermentation in order to reduce the risk on listeria outgrowth. the strain displays remarkable bacteriocin production kinetics. whereas most lactic acid b ...	2003	14596995
mycobacterium marinum escapes from phagosomes and is propelled by actin-based motility.	mycobacteria are responsible for a number of human and animal diseases and are classical intracellular pathogens, living inside macrophages rather than as free-living organisms during infection. numerous intracellular pathogens, including listeria monocytogenes, shigella flexneri, and rickettsia rickettsii, exploit the host cytoskeleton by using actin-based motility for cell to cell spread during infection. here we show that mycobacterium marinum, a natural pathogen of fish and frogs and an occa ...	2003	14597736
incidence of listeria monocytogenes in food and environmental samples in italy between 1990 and 1999: serotype distribution in food, environmental and clinical samples.	we report the findings of the study of 4185 food samples and 958 environmental samples collected in italy in the period 1990-1999 and tested for the presence of listeria monocytogenes. the strains isolated were biochemically and serologically characterised. we found a fairly high percentage of l. monocytogenes contamination in food (12.8%), whereas the level of contamination was lower in the environment (environment and work surfaces in food processing plants) (6.1%). serotyping showed a prevale ...	2003	14598931
sigma(b)-dependent expression patterns of compatible solute transporter genes opuca and lmo1421 and the conjugated bile salt hydrolase gene bsh in listeria monocytogenes.	listeria monocytogenes is a food-borne pathogen that can persist and grow under a wide variety of environmental conditions including low ph and high osmolarity. the alternative sigma factor sigma(b) contributes to l. monocytogenes survival under extreme conditions. the purpose of this study was to identify and confirm specific sigma(b)-dependent genes in l. monocytogenes and to characterize their expression patterns under various stress conditions. opuca, lmo1421 and bsh were identified as putat ...	2003	14600237
the role of dietary vitamin e in experimental listeria monocytogenes infections in turkeys.	the current study was designed to determine if dietary vitamin e influenced either the gut clearance or levels of peripheral blood cd4+ and cd8+ t lymphocytes in adult turkeys experimentally infected with listeria monocytogenes. turkeys were fed vitamin e (0, 100, or 200 iu) from day of hatch to time of necropsy. after 6 wk on the experimental diet, turkeys were orally inoculated with l. monocytogenes (approximately 10(9) cfu). to monitor infection status, cloacal swabs were taken on selected da ...	2003	14601733
rapid identification of listeria species by using restriction fragment length polymorphism of pcr-amplified 23s rrna gene fragments.	a molecular method based on restriction fragment length polymorphism (rflp) of pcr-amplified fragments of the 23s rrna gene was designed to rapidly identify listeria strains to the species level. two fragments (s1, 460 bp, and s2, 890 bp) were amplified from boiled dna. s2 was cut with the restriction enzymes xmni or cfoi and, if needed, s1 was digested by either alui or clai. this method was first optimized with six reference strains and then applied to 182 isolates collected from effluents of ...	2003	14602590
assessment of photodynamic destruction of escherichia coli o157:h7 and listeria monocytogenes by using atp bioluminescence.	antimicrobial photodynamic therapy was shown to be effective against a wide range of bacterial cells, as well as for fungi, yeasts, and viruses. it was shown previously that photodestruction of yeast cells treated with photosensitizers resulted in cell destruction and leakage of atp. three photosensitizers were used in this study: tetra(n-methyl-4-pyridyl)porphine tetratosylate salt (tmpyp), toluidine blue o (tbo), and methylene blue trihydrate (mb). a microdilution method was used to determine ...	2003	14602591
development of a synthetic minimal medium for listeria monocytogenes.	a defined solid and liquid minimal medium, htm, which contained methionine and cysteine as the sole amino acids, was developed for listeria monocytogenes. complex broth-grown l. monocytogenes had to adapt to htm by inducing amino acid biosyntheis. htm is the simplest minimal medium available for growth of l. monocytogenes.	2003	14602660
first documented outbreak of listeria monocytogenes in quebec, 2002.		2003	14603730
isolation of bartonella washoensis from a dog with mitral valve endocarditis.	we report the first documented case of bartonella washoensis bacteremia in a dog with mitral valve endocarditis. b. washoensis was isolated in 1995 from a human patient with cardiac disease. the main reservoir species appears to be ground squirrels (spermophilus beecheyi) in the western united states. based on echocardiographic findings, a diagnosis of infective vegetative valvular mitral endocarditis was made in a spayed 12-year-old female doberman pinscher. a year prior to presentation, the re ...	2003	14605197
identification of foodborne bacteria by infrared spectroscopy using cellular fatty acid methyl esters.	identification of bacterial species by profiling fatty acid methyl esters (fames) has commonly been carried out by using a 20-min capillary gas chromatographic procedure followed by library matching of fame profiles using commercial midi databases and proprietary pattern recognition software. fast gc (5 min) fame procedures and mass spectrometric methodologies that require no lipid separation have also been reported. in this study, bacterial identification based on the rapid (2 min) infrared mea ...	2003	14607413
comparison of a cultural method with listerscreen plus rapid'l.mono or pcr-elisa methods for the enumeration of l. monocytogenes in naturally contaminated sewage sludge.	cultural methods used to count listeria monocytogenes in sewage sludge are laborious and time consuming, and alternative methods are needed to reduce analysis time and improve detection limits. in this study, a survey of l. monocytogenes in sewage sludge is presented with a comparative study between a cultural method and immunomagnetic separation using a listerscreen test followed by identification of l. monocytogenes with rapid'l.mono agar or pcr-elisa. these two alternative methods improved th ...	2003	14607419
localized reactive oxygen and nitrogen intermediates inhibit escape of listeria monocytogenes from vacuoles in activated macrophages.	listeria monocytogenes (lm) evades being killed after phagocytosis by macrophages by escaping from vacuoles into cytoplasm. activated macrophages are listericidal, in part because they can retain lm in vacuoles. this study examined the contribution of reactive oxygen intermediates (roi) and reactive nitrogen intermediates (rni) to the inhibition of lm escape from vacuoles. lm escaped from vacuoles of nonactivated macrophages within 30 min of infection. macrophages activated with ifn-gamma, lps, ...	2003	14607950
increased cd8+ t cell memory to concurrent infection at the expense of increased erosion of pre-existing memory: the paradoxical role of il-15.	the use of cytokines during vaccination, particularly il-15, is being considered due to the unique ability of il-15 to enhance the proliferation of memory cd8(+) t cells. however, as homeostatic mechanisms limit excessive lymphocyte expansion, we addressed the consequences of this enhancement of t cell memory by il-15. infection of mice with either recombinant mycobacterium bovis (bcg) expressing il-15 (bcg-il-15) or bcg and purified il-15 resulted in an increased cd44, il-2rbeta expression and ...	2003	14607951
beta-casein-derived peptides, produced by bacteria, stimulate cancer cell invasion and motility.	in colon cancer, enteric bacteria and dietary factors are major determinants of the microenvironment but their effect on cellular invasion is not known. we therefore incubated human hct-8/e11 colon cancer cells with bacteria or bacterial conditioned medium on top of collagen type i gels. listeria monocytogenes stimulate cellular invasion through the formation of a soluble motility-promoting factor, identified as a 13mer beta-casein-derived peptide (hkempfpkypvep). the peptide is formed through t ...	2003	14609961
delivery of macromolecules into cytosol using liposomes containing hemolysin.		2003	14610821
characterization of virulent and avirulent listeria monocytogenes strains by pcr amplification of putative transcriptional regulator and internalin genes.	listeria monocytogenes is an opportunistic bacterial pathogen that is an important cause of human food-borne illness worldwide. however, l. monocytogenes strains demonstrate considerable variation in pathogenic potential. in this report, virulent and avirulent l. monocytogenes isolates were compared by using a comparative screening strategy. two clones were identified that contained dna that was only present in virulent l. monocytogenes strains. pcr primers were designed for three genes from the ...	2003	14614064
restricted translocation across the cell wall regulates secretion of the broad-range phospholipase c of listeria monocytogenes.	the virulence of listeria monocytogenes is directly related to its ability to spread from cell to cell without leaving the intracellular milieu. during cell-to-cell spread, bacteria become temporarily confined to secondary vacuoles. among the bacterial factors involved in escape from these vacuoles is a secreted broad-range phospholipase c (pc-plc), the activation of which requires processing of an n-terminal prodomain. mpl, a secreted metalloprotease of listeria, is involved in the proteolytic ...	2003	14526005
the infectious origins of stillbirth.	our objective was to determine the relationship between various types of perinatal infections and stillbirths.	2003	14526331
seca2-dependent secretion of autolytic enzymes promotes listeria monocytogenes pathogenesis.	pathogenic bacteria secrete proteins that promote invasion of host tissues and resistance to immune responses. however, secretion mechanisms that contribute to the enormous morbidity and mortality of gram-positive bacteria are largely undefined. an auxiliary protein secretion system (seca2) has recently emerged in listeria monocytogenes and eight other gram-positive pathogens. here, a proteomics approach identified seventeen seca2-dependent secreted and surface proteins of l. monocytogenes, the ...	2003	14527997
[occurrence of listeria monocytogenes in pre-sliced vacuum-packaged].	there is scarce information in brazil and other south american countries about the occurrence of listeria monocytogenes in food, mainly refrigerated ready-to-eat products. the consumption of sliced vacuum-packaged meat products has increased in the last few years. nevertheless, a complete assessment of the risk associated with l. monocytogenes in these products is still necessary. because of the production and storage characteristics of these products, they can be considered potential vehicles f ...	2003	14528609
an snp-based pcr assay to differentiate between listeria monocytogenes lineages derived from phylogenetic analysis of the sigb gene.	the alternative sigma factor sigb gene is involved in the stress response regulation of listeria monocytogenes, and contributes towards growth and survival in adverse conditions. this gene was examined to determine if it could be a useful indicator of lineage differentiation, similar to the established method based on ribotyping. the sigb sequence was resolved in four local l. monocytogenes strains and the phylogenetic relationship among these, and a further 21 sigb gene sequences from strains o ...	2003	14529964
a 6 x 6 drop plate method for simultaneous colony counting and mpn enumeration of campylobacter jejuni, listeria monocytogenes, and escherichia coli.	a protocol was developed using 96-well plates and multichannel pipettes for serial dilutions, followed by drop plating on agar in a 6 x 6 format. this protocol permits simultaneous plating of six dilutions which greatly decreases the number of plates utilized thereby saving incubator space for organisms such as campylobacter which require unique environmental conditions.	2003	14529971
highly biased type 1 immune responses in mice deficient in lfa-1 in listeria monocytogenes infection are caused by elevated il-12 production by granulocytes.	lfa-1 (cd11a/cd18) plays a key role in various inflammatory responses. here we show that the acquired immune response to listeria monocytogenes is highly biased toward type 1 in the absence of lfa-1. at the early stage of listeriosis, numbers of ifn-gamma producers in the liver and spleen of lfa-1(-/-) mice were markedly increased compared with heterozygous littermates and valpha14(+)nkt cell-deficient mice, and nk cells were major ifn-gamma producers. numbers of il-12 producers were also marked ...	2003	14530315
deficient anti-listerial immunity in the absence of perforin can be restored by increasing memory cd8+ t cell numbers.	compared with wild-type (wt) mice, listeria monocytogenes (lm)-vaccinated perforin-deficient (pko) mice have elevated levels of cd8(+) t cell memory, but exhibit reduced levels of protection against virulent lm. in this study, ag-specific cd8(+) t cells from lm-vaccinated wt and pko mice were used in adoptive transfer assays to determine the contribution of perforin-dependent cytolysis in protective immunity to lm. perforin deficiency resulted in an approximately 5-fold reduction in the per-cell ...	2003	14530349
selective depletion of nonspecific t cells during the early stage of immune responses to infection.	transient t cell depletion occurs before the development of an effective immune response to infection. in this study we show that most t cells, regardless of specificity, are induced to express early activation markers soon after infection with listeria monocytogenes or lymphocytic choriomeningitis virus. ag-specific t cells are further activated to display late activation markers and undergo extensive proliferation. as ag-specific t cells begin to expand, nonspecific t cells are depleted en mas ...	2003	14530360
behaviour of listeria monocytogenes in anchovies during marination.		2003	14535420
enhanced immunogenicity of siv gag dna vaccines encoding chimeric proteins containing a c-terminal segment of listeriolysin o.	we investigated the potential of the c-terminal 59-amino acid segment of listeriolysin o (llo) in enhancing immune responses against the siv gag antigen in the context of dna immunization. genes with codons optimized for mammalian expression were synthesized for the sivmac239 gag, a secreted siv gag protein with the tissue plasminogen antigen (tpa) signal fused to its n-terminus (tpa/gag), as well as their corresponding chimeric proteins gag/llo and tpa/gag/llo containing the c-terminal 59 amino ...	2003	14550583
cell biology. how cells step out.		2003	14551414
[rhomboencephalitis caused by listeria monocytogenes infection in the central nervous system].	listeria monocytogenes infections can involve the central nervous system in the form of a rhomboencephalitis. three possible cases of rhomboencephalitis by listeria monocytogenes are reported (2 females, aged 44 and 49 and a man of 36 years old). the three cases were preceded by an unspecific prodrome of headache, vertigo and fever in absence of a meningeal syndrome. the neurological stage was defined by the unilateral involvement of cranial nerves and the cerebellum and a clear inflammatory cer ...	2003	14558248
requirement of the listeria monocytogenes broad-range phospholipase pc-plc during infection of human epithelial cells.	in this study, we investigated the requirement of the listeria monocytogenes broad-range phospholipase c (pc-plc) during infection of human epithelial cells. l. monocytogenes is a facultative intracellular bacterial pathogen of humans and a variety of animal species. after entering a host cell, l. monocytogenes is initially surrounded by a membrane-bound vacuole. bacteria promote their escape from this vacuole, grow within the host cell cytosol, and spread from cell to cell via actin-based motil ...	2003	14563864
listeria intracellular growth and virulence require host-derived lipoic acid.	listeria monocytogenes is a gram-positive intracytosolic pathogen that causes severe disease in pregnant and immunocompromised individuals. we found that l. monocytogenes lacking the lipoate protein ligase lpla1 was defective for growth specifically in the host cytosol and was less virulent in animals by a factor of 300. a major target for lpla1, the e2 subunit of pyruvate dehydrogenase (pdh), lacked a critical lipoyl modification when the deltalpla1 strain was grown intracellularly, which sugge ...	2003	14564012
bactofection of mammalian cells by listeria monocytogenes: improvement and mechanism of dna delivery.	bacteria-mediated transfer of plasmid dna into mammalian cells (bactofection) is a potent approach to express plasmid-encoded heterologous proteins (protein antigens, toxins or enzymes) in a large set of different cell types including phagocytic and nonphagocytic mammalian cells. previously, we have described a listeria monocytogenes-mediated dna delivery system, which releases plasmid dna directly into the cytosol of mammalian cells by partial self-destruction of the carrier bacteria. here we r ...	2003	14566363
development of a protocol for the isolation of listeria monocytogenes from sludge.	given the high level of background flora in sludge, methods for detecting listeria monocytogenes are not well established. in this study, two critical parameters for the detection of l. monocytogenes were evaluated: the concentration of listeria sp. in a modified fraser broth (first stage of the method) and the proportion of l. monocytogenes on palcam agar (second stage of the method). concentrations of listeria sp. estimated in 118 modified fraser enrichment broths inoculated with four types of ...	2003	14568068
effect of asphalt fume inhalation exposure at simulated road paving conditions prior to bacterial infection on lung defense responses in rats.	asphalt fume inhalation has been suspected of affecting immune function in exposed workers. the objective of this study was to evaluate the effect of asphalt exposure on lung immune responses in rats using a bacterial infectivity model. pathogen-free male sprague-dawley rats were exposed by inhalation to asphalt fumes (72.6 +/- 4.95 mg/m3) or filtered air for 6 h/day for 5 days. one day after the final asphalt exposure, rats were intratracheally inoculated with 5 x 10(5) listeria monocytogenes. ...	2003	14569497
ena/vasp proteins: regulators of the actin cytoskeleton and cell migration.	ena/vasp proteins are a conserved family of actin regulatory proteins made up of evh1, evh2 domains, and a proline-rich central region. they have been implicated in actin-based processes such as fibroblast migration, axon guidance, and t cell polarization and are important for the actin-based motility of the intracellular pathogen listeria monocytogenes. mechanistically, these proteins associate with barbed ends of actin filaments and antagonize filament capping by capping protein (capz). in add ...	2003	14570581
development of a rapid 1-h fluorescence-based cytotoxicity assay for listeria species.	listeria monocytogenes is cytotoxic to the lymphocyte-origin hybridoma ped-2e9 cell line. the relative cytotoxicity can be calculated by assaying the release of alkaline phosphatase (alp) from the infected cell line. in this study, a fluorogenic substrate (4-methylumbelliferyl phosphate, mup) was used to quantify the alp activity. the assay is 3.5-fold more sensitive than the colorimetric-based assay and requires only 1 h to differentiate virulent from avirulent strains. in addition to various l ...	2003	14499993
host resistance of cd18 knockout mice against systemic infection with listeria monocytogenes.	mice with targeted mutations of cd18, the common beta2 subunit of cd11/cd18 integrins, have leukocytosis, impaired transendothelial neutrophil emigration, and reduced host defense to streptococcus pneumoniae, a gram-positive extracellular bacterium. previous studies using blocking monoclonal antibodies suggested roles for cd18 and cd11b in hepatic neutrophil recruitment and host innate response to listeria monocytogenes, a gram-positive intracellular bacterium. we induced systemic listeriosis in ...	2003	14500519
genome-scale design of pcr primers and long oligomers for dna microarrays.	during the last years, the demand for custom-made cdna chips/arrays as well as whole genome chips is increasing rapidly. the efficient selection of gene-specific primers/oligomers is of the utmost importance for the successful production of such chips. we developed genomepride, a highly flexible and scalable software for designing primers/oligomers for large-scale projects. the program is able to generate either long oligomers (40-70 bases), or pcr primers for the amplification of gene-specific ...	2003	14500820
real-time closed tube single nucleotide polymorphism (snp) quantification in pooled samples by quencher extension (qext).	quencher extension (qext) is a novel single step closed tube real-time method to quantify snps using reporters and quenchers in combination with primer extension. a probe with a 5'-reporter dye is single base extended with a dideoxy nucleotide containing a quencher dye if the target snp allele is present. the extension is recorded from the quenching (reduced fluorescence) of the reporter dye. this avoids the influence of the unincorporated dye-labeled nucleotides, resulting in high accuracy and ...	2003	14500845
"effectiveness of electrolyzed acidic water in killing escherichia coli o157:h7, salmonella enteritidis, and listeria monocytogenes on the surfaces of tomatoes," a comment on: j. food prot. 66(4):542-548 (2003).		2003	14503702
microbiological quality of open ready-to-eat salad vegetables: effectiveness of food hygiene training of management.	during september and october 2001, a microbiological study of open, ready-to-eat, prepared salad vegetables from catering or retail premises was undertaken to determine their microbiological quality. the study focused on those salad vegetables that were unwrapped and handled either by staff or customers in the premises where the sample was taken. examination of salad vegetables from food service areas and customer self-service bars revealed that most (97%; 2,862 of 2,950) were of satisfactory or ...	2003	14503709
survival of escherichia coli o157:h7, listeria monocytogenes, and salmonella in juice concentrates.	the survival of escherichia coli o157:h7, listeria monocytogenes, and salmonella was studied in apple, orange, pineapple, and white grape juice concentrates and banana puree. pouches of juice concentrate or puree were inoculated with pathogens at a level > or = 10(3) cfu/g and stored at -23 degrees c (-10 degrees f). pathogen survival was monitored at 6 and 24 h, once a week for four consecutive weeks, and biweekly thereafter until 12 weeks. when pathogens were not detectable by direct plating, ...	2003	14503711
thermal inactivation, growth, and survival studies of listeria monocytogenes strains belonging to three distinct genotypic lineages.	twenty-one listeria monocytogenes strains belonging to three different genotypic lineages were evaluated for differences between lineages and between individual strains with respect to thermal inactivation, growth, and survival. three sets of heat inactivation conditions (60 degrees c, ph 6.0, and 0.5 m lactate; 55 degrees c, ph 6.0, and 0.5 m lactate; and 50 degrees c, ph 4.0, and 0.5 m lactate) were used on strains grown in modified brain heart infusion (bhi) broth with and without glucose. tw ...	2003	14503714
thermal inactivation of listeria monocytogenes on ready-to-eat turkey breast meat products during postcook in-package pasteurization with hot water.	the inactivation of listeria monocytogenes during postcook in-package pasteurization was evaluated for fully cooked turkey breast meat products (4-kg packages). the products were surface-inoculated to contain 10(7) cfu of l. monocytogenes per cm2 of product surface. the inoculated products were vacuum-packaged in different thicknesses (0.08 to 0.33 mm) of packaging films and treated with hot water at 96 degrees c. after heat treatment, the products were immediately cooled in an ice water bath at ...	2003	14503715
prepackage surface pasteurization of ready-to-eat meats with a radiant heat oven for reduction of listeria monocytogenes.	in this paper, a thermal process for the surface pasteurization of ready-to-eat (rte) meat products for the reduction of listeria monocytogenes on such products (turkey bologna, roast beef, corned beef, and ham) is described. the process involves the passage of products through a "tunnel" of heated coils on a stainless steel conveyor belt at various treatment times relevant to the manufacture of processed meat for the surface pasteurization of rte meat products. two inoculation procedures, dip a ...	2003	14503716
synergy between nisin and select lactates against listeria monocytogenes is due to the metal cations.	listeria monocytogenes, a major foodborne pathogen, has been responsible for many outbreaks and recalls. organic acids and antimicrobial peptides (bacteriocins) such as nisin are produced by lactic acid bacteria and are commercially used to control pathogens in some foods. this study examined the effects of lactic acid (la) and its salts in combination with a commercial nisin preparation on the growth of l. monocytogenes scott a and its nisin-resistant mutant. because of an increase in its activ ...	2003	14503717
inactivation of escherichia coli o157:h7, listeria monocytogenes, and salmonella in cranberry, lemon, and lime juice concentrates.	the production of thermally concentrated fruit juices uses temperatures high enough to achieve at least a 5-log reduction of pathogenic bacteria that can occur in raw juice. however, the transportation and storage of concentrates at low temperatures prior to final packaging is a common practice in the juice industry and introduces a potential risk for postconcentration contamination with pathogenic bacteria. the present study was undertaken to evaluate the likelihood of escherichia coli o157:h7, ...	2003	14503718
a pcr method based on 16s rrna sequence for simultaneous detection of the genus listeria and the species listeria monocytogenes in food products.	the genus listeria comprises six closely related species, of which only listeria monocytogenes is a human pathogen. the rapid and sensitive detection of l. monocytogenes is important in the food industry as well as in medical diagnosis. in this study, a pcr-based method for the rapid, specific, and sensitive detection of l. monocytogenes in food products was developed. the pcr is based on dna sequences and primer pairs that are found within the 16s subunit of the rrna gene and are specific to th ...	2003	14503721
evaluation of several modifications of an ecometric technique for assessment of media performance.	recovery of listeria monocytogenes 101m, jonesia denitrificans, salmonellae, and pediococcus sp. nrrl b-2354 across nine media was evaluated with three modified versions of an ecometric method. two approaches involved the use of broth cultures (10(8) to 10(9) cfu/ml) of individual strains and either large (10-microl) or small (1-microl) presterilized plastic loops. the third approach involved precultured slants and the inoculation of media with presterilized plastic inoculating needles (10(4) cf ...	2003	14503736
the role of human dendritic cells in meningococcal and listerial meningitis.	few bacteria are capable of causing infections of the central nervous system (cns), one of the most subtly shielded anatomical structures within the human body. neisseria meningitidis is an important cause of bacterial meningitis and commonly affects otherwise healthy infants and adolescents. in contrast, listeria monocytogenes is a cause of septicaemia and meningitis in neonates and immunocompromised adults. dendritic cells (dcs) provide the physical link between the innate and adaptive immune ...	2003	14503789
characterization of a unique sigma54-dependent pts operon of the lactose family in listeria monocytogenes.	the sigma(54) subunit of the rna polymerase directs the expression of specific operons in association with cognate activators. three different activators have been detected in the listeria monocytogenes genome on the basis of the high conservation of a specific domain. among them, the lacr activator, of the levr family, was found just upstream from a newly described sigma(54)-dependent operon, lpo, which presents a classical -24/-12 consensus promoter. the lpo operon encodes proteins similar to ...	2003	14505817
genome and proteome of listeria monocytogenes phage psa: an unusual case for programmed + 1 translational frameshifting in structural protein synthesis.	psa is a temperate phage isolated from listeria monocytogenes strain scott a. we report its complete nucleotide sequence, which consists of a linear 37 618 bp dna featuring invariable, 3'-protruding single stranded (cohesive) ends of 10 nucleotides. the physical characteristics were confirmed by partial denaturation mapping and electron microscopy of dna molecules. fifty-seven open reading frames were identified on the psa genome, which are apparently organized into three major transcriptional u ...	2003	14507382
immunological function in mice exposed to jp-8 jet fuel in utero.	immunological parameters, host resistance, and thyroid hormones were evaluated in f1 mice exposed in utero to jet propulsion fuel-8 (jp-8). c57bl/6 pregnant dams (mated with c3h/hej males) were gavaged daily on gestation days 6-15 with jp-8 in a vehicle of olive oil at 0, 1000, or 2000 mg/kg. at weaning (3 weeks of age), no significant differences were observed in body, liver, spleen, or thymus weight, splenic and thymic cellularity, splenic cd4/cd8 lymphocyte subpopulations, or t-cell prolifera ...	2003	14514957
in vivo role of ifn-gamma produced by antigen-presenting cells in early host defense against intracellular pathogens.	antigen-presenting cells (apc), including dendritic cells and macrophages, produce a large amount of interferon (ifn)-gamma, a crucial cytokine for the control of infectious diseases. to elucidate the role of ifn-gamma from apc in vivo, we employed cytokine receptor common gamma subunit (gamma c) and recombination-activating gene (rag)-2 double-knockout (gamma c(-/-(y))-rag-2(-/-)) mice, which are severely impaired in ifn-gamma production and are extremely susceptible to infection of intracellul ...	2003	14515250
differences in maintenance of cd8+ and cd4+ bacteria-specific effector-memory t cell populations.	our knowledge about the kinetics and dynamics of complex pathogen-specific cd8(+) t cell responses and the in vivo development of cd8(+) memory t cells has increased substantially over the past years; in comparison, relatively little is known about the cd4(+) t cell compartment. we monitored and directly compared the phenotypical changes of pathogen (listeria monocytogenes)-specific cd8(+) and cd4(+) t cell responses under conditions leading to effective and long-lasting protective immunity. we ...	2003	14515271
bacterial pathogenesis: exploiting cellular adherence.	cell adhesion molecules, such as integrins, cadherins, the immunoglobulin superfamily of cell adhesion molecules and selectins, play important structural roles and are involved in various signal transduction processes. as an initial step in the infectious process, many bacterial pathogens adhere to cell adhesion molecules as a means of exploiting the underlying signaling pathways, entering into host cells or establishing extracellular persistence. often, bacteria are able to bind to cell adhesio ...	2003	14519399
[active surveillance on listeria monocytogenes in seven kinds of food in 11 provinces of china in 2001].	to carry out national active surveillance on listeria monocytogenes in foods in china.	2003	14521783
listeria monocytogenes rotates around its long axis during actin-based motility.		2003	14521850
heteroduplex mobility assay for the identification of listeria sp and listeria monocytogenes strains: application to characterisation of strains from sludge and food samples.	one hundred and ten listeria sp. isolates from sewage sludge were identified according to phenotypic and genotypic methods. the listeria sp. strains isolated from five types of sludge from three sewage treatment plants in angers (france) and the surrounding area included l. monocytogenes (55.5%), l. innocua (29.1%), l. seeligeri (13.6%) and l. welshimeri (1.8%). the majority of l. monocytogenes strains belonged to serotypes 4b, 1/2b and 1/2a. moreover, a heteroduplex mobility assay based on the ...	2003	14522461
listeria monocytogenes infection in patients with cancer.	listeriosis (lt) is an important infection in immunocompromised patients, but no large series of lt in cancer patients have been recently described. we reviewed the records of 34 cancer patients with lt at our institution (1990-2001). twenty patients (59%) had an underlying hematologic malignancy. in 11 patients, lt complicated bone marrow transplantation. lymphocytopenia was observed in 62% of the patients. twenty-six patients (76%) received prior corticosteroids. bacteremia was the most common ...	2003	14522512
in vitro antimicrobial activity of moxifloxacin compared to other quinolones against recent clinical bacterial isolates from hospitalized and community-based cancer patients.	the in vitro spectrum of moxifloxacin (a c-8-methoxyquinolone) was compared to that of ciprofloxacin and levofloxacin against 924 recent clinical isolates from cancer patients. moxifloxacin was more active than the comparator agents against gram-positive pathogens, with potent activity against aerococcus spp., listeria monocytogenes, micrococcus spp., rhodococcus equi, and stomatococcus mucilaginous, methicillin-susceptible staphylococcus spp., all beta hemolytic streptococci, viridans streptoco ...	2003	14522520
cd2+ and the n-terminal metal-binding domain protect the putative membranous cpc motif of the cd2+-atpase of listeria monocytogenes.	cada, the cd(2+)-atpase of listeria monocytogenes, contains four cysteine residues: two in the ctnc (cys-thr-asn-cys) sequence in the cytoplasmic metal-binding domain (mbd), and two in the cpc (cys-pro-cys) sequence in the membrane domain. taking advantage of deltambd, a truncated version of cada that lacks the mbd but which still acts as a functional cd(2+)-atpase [bal, mintz, guillain and catty (2001) febs lett. 506, 249-252], we analysed the role of the membrane cysteine residues (studied usi ...	2003	12383056
antibacterial activity of extracts from some edible plants commonly consumed in asia.	extracts of edible plants (26 species) from china, japan, thailand and yemen were screened for their antibacterial activity against bacillus cereus, staphylococcus aureus, listeria monocytogenes, escherichia coli and salmonella infantis. buffered methanol (80% methanol and 20% pbs) and acetone extracted inhibitory substances against tested bacteria from 16 plants, as revealed by the disc assay. the minimum inhibitory concentrations (mics) of extracts determined by the agar dilution method ranged ...	2003	12423924
interactive inhibition of meat spoilage and pathogenic bacteria by lysozyme, nisin and edta in the presence of nitrite and sodium chloride at 24 degrees c.	to develop a nisin- and lysozyme-based antimicrobial treatment for use with processed ham and bologna, in vitro experiments were conducted to determine whether inhibition enhancing interactions occur between the antimicrobials lysozyme, chrisin (a commercial nisin preparation), edta, nacl and nano(2). inhibitory interactions were observed between a number of agents when used against specific pathogenic and spoilage bacteria. the observed interactions included lysozyme with edta (enterococcus fae ...	2003	12423927
estimation of low bacterial concentration: listeria monocytogenes in raw milk.	a time-series bacteriological analysis has been carried out on milk collected on farms from 1997 to 2001 by a plant producing raw milk soft cheese, with the purpose of assessing the time course of the presence/absence of listeria monocytogenes. a standard data collection procedure was used, in which farms were tested on a monthly or biweekly basis and 2-3 days after the detection of milk tanker contamination. this procedure yielded low figures for contamination frequencies. the average value and ...	2003	12430767
effects of cis-nonachlor, trans-nonachlor and chlordane on the immune system of sprague-dawley rats following a 28-day oral (gavage) treatment.	the immunotoxicity of cis- and trans-nonachlor and chlordane were investigated in adult male and female sprague-dawley rats following a 28-day oral (gavage) treatment. rats were randomly assigned to six experimental groups: cis-nonachlor, females; trans-nonachlor, females; technical chlordane females; cis-nonachlor, males; trans-nonachlor, males; technical chlordane, males. the immunologic endpoints included: quantification of the total serum immunoglobulin (ig) levels and subclasses and flow cy ...	2003	12453735
detection of pathogenic listeria spp. in zoo animal faeces: use of immunomagnetic separation and a chromogenic isolation medium.	faecal samples, collected from 200 healthy animals in antwerp zoo, were examined for the presence of pathogenic listeria spp. a two-stage standard isolation (iso) method was combined with immunomagnetic separation (ims). aloa agar, a chromogenic isolation medium, differentiating listeria spp. on the basis of beta-glucosidase and phosphatidylinositol-specific phospholipase c (piplc) activity, was compared with palcam agar. confirmation of the isolates was based on conventional biochemical tests a ...	2003	12458161
estimation of uncertainty and variability in bacterial growth using bayesian inference. application to listeria monocytogenes.	the usefulness of risk assessment is limited by its ability or inability to model and evaluate risk uncertainty and variability separately. a key factor of variability and uncertainty in microbial risk assessment could be growth variability between strains and growth model parameter uncertainty. in this paper, we propose a bayesian procedure for growth parameter estimation which makes it possible to separate these two components by means of hyperparameters. this model incorporates in a single st ...	2003	12457583
the development of an efficient and rapid enzyme linked fluorescent assay method for the detection of listeria spp. from foods.	conventional isolation methods, including the health products and food branch (hpfb), health canada method used for the isolation and identification of listeria species and listeria monocytogenes from foods and environmental samples, can take a week or more to complete and are usually labor-intensive. this has led to the development of various rapid methods which attempt to generate results comparable to standard methods but in a reduced time-frame with less hands-on operation. our previous work ...	2003	12457586