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brain abscesses in children with cancer.brain abscesses in pediatric patients are rare events, and the causative organism and prognosis vary with the population under study. children with cancer seem to be particularly susceptible to the development of brain abscesses because of the immunological changes induced by cancer and its treatment. we reviewed the records of children who developed a brain abscess during treatment of a malignancy to define the clinical characteristics, prognosis, and management of these patients.19989607425
[listeria monocytogenes meningitis. case reports in patients from the federal district].it has been shown the role of listeria monocytogenes as a etiological agent identified by bacteriological analysis among cases of human meningitis in distrito federal, brazil. laboratorial characteristics and some clinical and epidemiological aspects are reported.19989608235
the focal adhesion phosphoprotein, vasp.vasodilator-stimulated phosphoprotein (vasp) is associated with focal adhesions and areas of dynamic membrane activity, where it is thought to have an important role in actin filament assembly and cell motility. vasp contains a central proline-rich sequence which recruits the g-actin binding protein profilin. localization of vasp to the leading edge of a migrating cell can lead to local accumulation of profilin, which in turn can supply actin monomers to growing filament ends. vasp binds to the ...19989611773
molecular characterization of an autolytic amidase of listeria monocytogenes egd.the gene encoding a 102 kda autolysin has been cloned from an expression library of listeria monocytogenes egd genomic dna, using a direct screening protocol. the encoded protein has two domains, an n-terminal enzymic domain showing a high level of homology to the amidase domain of the major autolysin (atl) of staphylococcus aureus, and a c-terminal, putative cell-wall-binding domain containing four imperfect direct repeats. in order to examine the role of the enzyme, the autolysin-encoding gene ...19989611810
[endocarditis caused by listeria monocytogenes on a prosthetic valve: presentation of a case and review of the bibliography]. 19989611883
[antibacterial activity of lactobacilli].the antagonistic action of lactobacilli is an important factor in the protection of the vagina of fertile women from infection by other microorganisms. in the present study the authors investigated 17 strains of lactobacilli, incl. 11 of vaginal origin. the objective was to investigate in more detail the antibacterial activity of lactobacilli and to attempt to assess substances responsible for inhibition. the investigated lactobacilli inhibited some strains of escherichia coli, serratia marcesce ...19989611889
studying the effect of temperature on microbial growth using multiplicative model.the specific growth rates of brochothrix thermosphacta, listeria monocytogenes, yersinia enterocolitica, bacillus cereus, escherichia coli o157:h7, salmonella spp., staphylococcus aureus and clostridium perfringens at various temperatures were taken from the food micromodel database, and the data sets of specific growth rate versus temperature were fitted using the multiplicative model (r = a td, r = specific growth rate; t = temperature; a, d = regression parameters). the exponential d-value de ...19989615472
docosahexaenoic acid, a constituent of fetal and neonatal serum, inhibits nitric oxide production by murine macrophages stimulated by ifn gamma plus lps, or by ifn gamma plus listeria monocytogenes.murine macrophage activation is deficient in the fetus and the neonate, and in areas of the placenta perfused by the fetal circulation. fetal and neonatal serum concentrations of docosahexaenoic acid (dha) are 150 microm, or approximately 50-fold higher than in the adult. we previously showed that dha inhibits activation of the gene for inducible nitric oxide synthase (inos) in murine macrophages stimulated in vitro with interferon gamma (ifn gamma) plus lipopolysaccharide (lps). we have now pur ...19989616876
effects of great lakes fish consumption on the immune system of sprague-dawley rats investigated during a two-generation reproductive study.the effects of great lakes fish contaminants on several quantitative and functional aspects of the immune system were investigated in the first (f1) and second (f2) generations of sprague-dawley rats. the f0 rats were fed either a control diet or diets containing 5 or 20% lyophilized chinook salmon from the credit river of lake ontario (lo) and owen sound point of lake huron (lh). the f1 and f2 pups were exposed to fish in utero, through the dam's milk to 21 days old, and through the dam's respe ...19989618333
prediction of listeria spp. growth as affected by various levels of chemicals, ph, temperature and storage time in a model broth.the effects of concentration of nacl (0.5 to 12.5%), methyl paraben (0.0 to 0.2%), sodium propionate (0.3%), sodium benzoate (0.1%), potassium sorbate (0.3%), ph (> 5.9) temperature (4 to 30 degrees c), storage time (up to 58 d) and inoculum (> 10(5) to > 10(-2) per ml) on the log10 probability percentage of one cell of listeria spp. to initiate growth in a broth system were evaluated in a factorial design study. at ph 5.96 and temperature ranging from 4 to 30 degrees c the concentrations of sod ...19989620122
antimicrobial spectrum and target site of d-3-phenyllactic acid.geotrichum candidum excretes d-3-phenyllactic acid, which inhibits the growth of listeria monocytogenes. it was found to inhibit a range of gram-positive bacteria found in humans and foodstuffs, such as staphylococcus aureus and enterococcus faecalis, and gram-negative bacteria from humans, such as providencia stuartii and klebsiella oxytoca. scanning electron microscope studies on the effect of d-3-phenyllactic acid on l. monocytogenes showed that it caused changes in bacterial behavior and str ...19989620125
model of the influence of time and mild temperature on listeria monocytogenes nonlinear survival curves.heat treatment has long been regarded as one of the most widely used and most effective means of destroying pathogens in food. up to now the linear relationship between the death rate and the temperature has been used when choosing the best heat treatment to apply. however, the information given by this linear relationship is no longer sufficient when nonlinear survival curves are observed. consequently, the agri-food industry needs a tool to choose the best mild heat treatment to apply in the c ...19989620126
induction of cytokine messenger rna transcripts in mouse macrophages by listeria monocytogenes isolated from channel catfish.to determine whether differences exist in induction and quantity of tumor necrosis factor alpha (tnf-alpha), interleukin (il)1 beta, and il-10 mrna transcripts when mouse j774a.1 macrophages are infected with listeria monocytogenes, including 2 isolates originating from channel catfish, the wild-type virulent (egd) strain, and a nonhemolytic strain (atcc 15313).19989622740
systemic dissemination by intrarectal infection with listeria monocytogenes in mice.orally ingested listeria monocytogenes is known to penetrate into peyer's patches (pp) and translocate to the spleen and liver. herein, extraintestinal dissemination of the bacterium independent of pp was investigated. dissemination of listeriae to the spleen and liver was observed in intrarectally infected mice as well as in intragastrically infected animals in spite that no listeriae were detected in the small intestines of mice infected intrarectally. decreased numbers of intestinal intraepit ...19989623921
survey of food safety awareness among hiv positive individuals.a survey was carried out by personal interview to assess the awareness of basic food hygiene and food safety amongst 77 hiv-positive individuals attending a single hospital. there was some confusion and lack of knowledge about aspects of food storage and despite the fact that 74% of subjects had modified their diet since learning their hiv status (mainly for nutritional reasons) only 25% reported receiving information on food safety. of the subjects interviewed 96%, 66% and 23% were aware of the ...19989625907
suppression of major histocompatibility complex class i and class ii gene expression in listeria monocytogenes-infected murine macrophages.macrophage cells play a central role during infection with listeria monocytogenes by both providing a major habitat for bacterial multiplication and presenting bacterial antigens to the immune system. in this study, we investigated the influence of l. monocytogenes infection on the expression of mhc class i and class ii genes in two murine macrophage cell lines. steady-state levels of i-abeta chain mrna were decreased in both resting j774a.1 and p388d1 macrophages infected with l. monocytogenes ...19989626934
long-lived protective immunity to listeria is conferred by immunization with particulate or soluble listerial antigen preparations coadministered with il-12.the ability of il-12 to promote the development of th1-type immune responses, and thus promote cellular immunity, has been well documented. in a previous report, we showed that coadministration of il-12 with heat-killed listeria monocytogenes elicited intense antigen-specific t cell responses that conferred protective listerial immunity. herein, we have extended those studies by demonstrating that multiple injections of heat-killed l. monocytogenes and il-12 elicit memory responses that confer l ...19989630835
metal ion homeostasis and intracellular parasitism.bacteria possess multiple mechanisms for the transport of metal ions. while many of these systems may have evolved in the first instance to resist the detrimental effects of toxic environmental heavy metals, they have since become adapted to a variety of important homeostatic functions. the 'p'-type atpases play a key role in metal ion transport in bacteria. a cu+-atpase from the intracellular bacterium listeria monocytogenes is implicated in pathogenesis, and similar pumps in mycobacterium tube ...19989632246
purification of the inlb gene product of listeria monocytogenes and demonstration of its biological activity.entry of listeria monocytogenes into nonphagocytic cells requires the inlab gene products. inla and inlb are bacterial cell wall-associated polypeptides that can be released by sodium dodecyl sulfate treatment. by applying more gentle extraction methods, we have purified inlb in its native form. treatment of bacteria with various nondenaturating agents including mutanolysin, thiol reagents, sodium chloride, and detergents like triton x-100 or 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulf ...19989632576
construction and vaccine potential of acapsular mutants of erysipelothrix rhusiopathiae: use of excision of tn916 to inactivate a target gene.we previously showed that acapsular transposon tn916 mutants of erysipelothrix rhusiopathiae are avirulent for mice. in this study, we constructed nonreverting acapsular mutants and examined the vaccine potential of the mutants in mice. a representative acapsular transposon mutant, 33h6, was plated on selective agar containing autoclaved chlortetracycline and quinaldic acid, and two tetracycline-sensitive mutants were obtained. sequence analysis of chromosomal regions of the mutants in which tn9 ...19989632592
the inla gene of listeria monocytogenes lo28 harbors a nonsense mutation resulting in release of internalin.internalin is a surface protein that mediates entry of listeria monocytogenes egd into epithelial cells expressing the cell adhesion molecule human e-cadherin or its chicken homolog, l-cam, which act as receptors for internalin. after observing that entry of l. monocytogenes lo28 into s180 fibroblasts, in contrast to that of egd, did not increase after transfection with l-cam, we examined both the expression and the structure of internalin in strain lo28. we discovered a nonsense mutation in inl ...19989632615
nonspecific early protective immunity in francisella and listeria infections can be dependent on lymphocytes.normal mice, but not lymphocyte-deficient or b-cell-deficient mice, given a sublethal infection of francisella tularensis lvs survive a secondary lethal challenge of more than 10,000 50% lethal doses given 3 days later. in this work, we show that similar early protection that is also strongly lymphocyte dependent operates in listeria monocytogenes infection. since sublethal infection with either lvs or l. monocytogenes protects against heterologous lethal challenge, this early protection is nons ...19989632626
detection and characterization of a bacteriocin produced by lactococcus lactis subsp. cremoris r isolated from radish.bacteria isolated from radish were identified as lactococcus lactis subsp. cremoris r and their bacteriocin was designated lactococcin r. lactococcin r was sensitive to some proteolytic enzymes (proteinase-k, pronase-e, proteases, pepsin, alpha-chymotrypsin) but was resistant to trypsin, papain, catalase, lysozyme and lipase, organic solvents, or heating at 90 degrees c for 15, 30 and 60 min, or 121 degrees c for 15 min. lactococcin r remained active after storage at -20 and -70 degrees c for 3 ...19989633097
mathematical modelling of the heat resistance of listeria monocytogenes.the heat resistance of listeria monocytogenes phagovar 2389/2425/3274/2671/47/108/340 (1992 french outbreak strain) in broth was studied at 55, 60 and 65 degrees c. experiments were carried out on bacterial cultures in three different physiological states: cultures at the end of the log phase, cultures heat-shocked at 42 degrees c for 1 h, and subcultures of cells resistant to prolonged heating. survivor curves were better fitted using a sigmoidal equation than the classical log-linear model. th ...19989633632
qsars for the effect of benzaldehydes on foodborne bacteria and the role of sulfhydryl groups as targets of their antibacterial activity.quantitative structure activity relationships (qsars) were obtained describing the activity of a series of benzaldehydes against three different foodborne bacteria, listeria monocytogenes f6861, serotype 4b, salmonella enteritidis, phage type 4, p167807 and lactobacillus plantarum int.l11. mic values at ph 6.2 and 35 degrees c were obtained for 11 phenolic benzaldehydes to produce multiple linear regression and artificial neural network models. for each organism, the models contained a steric pa ...19989633634
sensitivity of food pathogens to garlic (allium sativum).the inhibitory activity of garlic (allium sativum) against staphylococcus aureus, salmonella typhi, escherichia coli and listeria monocytogenes was measured by the 'turbidity' method. minimum inhibitory concentration (mic) of garlic at 80% inhibition level was calculated for these bacteria. all bacterial pathogenic strains tested were inhibited by garlic; e. coli was most sensitive and listeria monocytogenes was least sensitive. therefore, garlic has potential for the preservation of processed f ...19989633635
heat resistance of listeria monocytogenes in dairy products as affected by the growth medium.listeria monocytogenes strains 1151 and scott a were grown in broth at 30 degrees c and transferred to half cream, double cream and butter stored at 5 degrees c to determine the influence of dairy product composition on heat resistance at 52, 56, 60, 64 and 68 degrees c. strain 1151 showed a higher heat resistance than strain scott a. the heat resistance of both strains was higher in the dairy products than in broth, particularly at lower temperatures. a significant difference was observed betwe ...19989633638
polymorphism of listeria monocytogenes and listeria innocua strains isolated from short-ripened cheeses.thirty isolates of listeria monocytogenes and 18 of l. innocua obtained from different short-ripened cheeses manufactured in asturias (northern spain), were compared with each other and with reference strains using serotype, phage type and pulsed-field restriction endonuclease digestion profiles analysis of the total dna. restriction enzymes apai and smai defined five clusters in l. monocytogenes (m1 to m5) and two main clusters in l. innocua (i1 and i2). cluster i2 was further arranged into thr ...19989633640
radiation inactivation of some food-borne pathogens in fish as influenced by fat levels.the influence of low (0.39-1.1%), medium (4.25%) and high (7.1-32.5%) fat levels in fish on radiation inactivation of four food-borne pathogens was investigated. cells of listeria monocytogenes 036, yersinia enterocolitica f5692, bacillus cereus and salmonella typhimurium at logarithmic phase were inoculated in 10% fish homogenates and subjected to gamma irradiation at ice temperature (0-1 degree c) with doses ranging from 0.05 to 0.8 kgy. the radiation survival curves of l. monocytogenes and b. ...19989633646
sensitivity to commercial disinfectants, and the occurrence of plasmids within various listeria monocytogenes genotypes isolated from poultry products and the poultry processing environment.the european suspension test was used to assess the relative resistance of 19 individual listeria monocytogenes genotypes, isolated from the poultry processing environment, to three commercially used disinfectants employed in the plant at the time of their isolation. to establish the relative resistance between the strains, the concentration of each disinfectant was reduced until inter-strain variation became apparent. for darasan 214 and 7058, variation was detected at 0.1% and 0.5% v/v, respec ...19989633661
evaluation of the extent and type of bacterial contamination at different stages of processing of cooked ham.in an attempt to determine the composition and origin of the spoilage flora of refrigerated vacuum-packed cooked ham, the changes in microbial numbers and types were followed along the processing line. results revealed lactobacillus sake and leuconostoc mesenteroides ssp. mesenteroides as the major causative agents of spoilage of sliced ham stored at 4 degrees c and 12 degrees c, due to recontamination in the cutting room. on the contrary, the progressive deterioration of whole ham under the sam ...19989633662
aberrant expression and potential function for parotid secretory protein (psp) in the nod (non-obese diabetic) mouse. 19989634989
th1 cells specific for a secreted protein of listeria monocytogenes are protective in vivo.in the present study we have investigated the role of the secreted p60 protein from listeria monocytogenes as an ag for cd4 t cells. the p60 protein is an abundant extracellular protein that is highly conserved within the members of the genus listeria. our results show that l. monocytogenes infection induces a potent p60-specific th1 immune response. remarkably, we found that p60-specific th1 clones mediate significant protection against l. monocytogenes infection. for one p60-specific clone, th ...19989637521
il-6 produced by kupffer cells induces stat protein activation in hepatocytes early during the course of systemic listerial infections.kupffer cells were the principal source of il-6 produced in the livers of mice following i.v. inoculation of listeria monocytogenes. il-6 mrna expression and the production of il-6 were reduced drastically within the nonparenchymal liver cell population derived from mice rendered kupffer cell depleted by pretreatment with liposome-encapsulated dichloromethylene diphosphonate. a sharp increase in the appearance of activated stat3 occurred in extracts of purified hepatocytes derived from normal mi ...19989637522
altered intestinal immune system but normal antibacterial resistance in the absence of p-selectin and icam-1.icam-1 and p-selectin are adhesion molecules that regulate leukocyte migration, extravasation to inflammatory sites, and other immune cell interactions. t cell-mediated resistance against acute infection with listeria monocytogenes and chronic infection with mycobacterium bovis calmette-guérin bacillus was investigated in mutant mice lacking p-selectin and/or icam-1. mice deficient in p-selectin (psel-/-), icam-1 (icam-/-), or the combination of both (psel-/- x icam-/-) showed normal bacterial c ...19989637528
[a case of listeria monocytogenes sepsis in an elderly who survived].a 81-year-old man who complained of fever and disturbance of consciousness was admitted to our hospital. listeria monocytogenes type 1/2aa was cultured from only the blood. he was treated with gamma-globrine and sensitive antibiotics (papm/bp, em) immediately after admission, and recovered in spite of multiple organ failure due to septic shock. he was not an immunocompromised host and did not have complication of meningitis, but had rhabdomyolysis and liver dysfunction.19989642946
attenuated listeria monocytogenes carrier strains can deliver an hiv-1 gp120 t helper epitope to mhc class ii-restricted human cd4+ t cells.listeria monocytogenes is a facultative intracellular pathogen which, following uptake by macrophages, escapes from the phagosome and replicates in the cytoplasm. this property has been exploited using recombinant l. monocytogenes as a carrier for the intracytoplasmic expression of antigens when mhc class i-restricted cytotoxic t lymphocyte responses are required. much less is known of the ability of these bacteria to trigger mhc class ii-restricted responses. here, we demonstrate that after ing ...19989645361
[comment on the letter to the editor: "acute hydrocephalus and cerebral abscess in meningitis due to listeria monocytogenes"]. 19989646634
interaction of human arp2/3 complex and the listeria monocytogenes acta protein in actin filament nucleation.actin filament assembly at the cell surface of the pathogenic bacterium listeria monocytogenes requires the bacterial acta surface protein and the host cell arp2/3 complex. purified arp2/3 complex accelerated the nucleation of actin polymerization in vitro, but pure acta had no effect. however, when combined, the arp2/3 complex and acta synergistically stimulated the nucleation of actin filaments. this mechanism of activating the host arp2/3 complex at the l. monocytogenes surface may be similar ...19989651243
evolution of a complex t cell receptor repertoire during primary and recall bacterial infection.the mechanisms underlying the genesis and maintenance of t cell memory remain unclear. in this study, we examined the evolution of a complex, antigen-specific t cell population during the transition from primary effector to memory t cells after listeria monocytogenes infection. t cell populations specific for listeriolysin o (llo)91-99, the immunodominant epitope recognized by h2-kd-restricted t lymphocytes, were directly identified in immune spleens using tetrameric h2-kd-epitope complexes. the ...19989653084
targeted disruption of the interferon-gamma receptor 2 gene results in severe immune defects in mice.to study the role of the interferon- (ifn) gammar2 chain in ifn-gamma signaling and immune function, ifn-gammar2-deficient mice have been generated and characterized. cells derived from ifn-gammar2 -/- mice are unable to activate either jak/stat signaling proteins or gene transcription in response to ifn-gamma. the lack of ifn-gamma responsiveness alters ifn-gamma-induced ig class switching by b cells from these mice. in vitro cultures of t cells demonstrate that the t cells from the ifn-gammar2 ...19989653170
listeria monocytogenes and serratia marcescens infections as models for th1/th2 immunity in laboratory cats.five species of bacteria known to be naturally-occurring pathogens of cats were screened for their ability to grow in feline macrophages in vitro, and to induce antibodies and delayed type hypersensitivity (dth) responses in vivo. two of these organisms, l. monocytogenes and s. marcescens, were selected for further study based on clear-cut differences in their in vitro and in vivo behavior. listeria was macrophage tropic, induced dth, and evoked poor antibody responses post-recovery, whereas ser ...19989656444
general stress transcription factor sigmab and its role in acid tolerance and virulence of listeria monocytogenes.the gene encoding the general stress transcription factor sigmab in the gram-positive bacterium listeria monocytogenes was isolated with degenerate pcr primers followed by inverse pcr amplification. evidence for gene identification includes the following: (i) phylogenetic analyses of reported amino acid sequences for sigmab and the closely related sigmaf proteins grouped l. monocytogenes sigmab in the same cluster with the sigmab proteins from bacillus subtilis and staphylococcus aureus, (ii) th ...19989658010
effect of in vitro monocyte activation by listeria monocytogenes antigens on phagocytosis and production of reactive oxygen and nitrogen radicals in bovines.macrophages by virtue of their phagocytic and antibacterial activities play an important role in the host resistance to intracellular pathogens including listeria monocytogenes. however, the precise killing mechanism adopted by macrophages in the case of l. monocytogenes and the role of macrophage activation in bacterial killing are still unclear. in the present investigation, different antigens of pathogenic l. monocytogenes and three non-specific activators, namely, lipopoly-saccharide (lps), ...19989661264
diagnosis of meningococcal meningitis by broad-range bacterial pcr with cerebrospinal fluid.we used broad-range bacterial pcr combined with dna sequencing to examine prospectively cerebrospinal fluid (csf) samples from patients with suspected meningitis. fifty-six csf samples from 46 patients were studied during the year 1995. genes coding for bacterial 16s and/or 23s rrna genes could be amplified from the csf samples from five patients with a clinical picture consistent with acute bacterial meningitis. for these patients, the sequenced pcr product shared 98.3 to 100% homology with the ...19989665992
interactions of listeria monocytogenes with mammalian cells during entry and actin-based movement: bacterial factors, cellular ligands and signaling.although <50 kb of its 3.3 megabase genome is known, listeria monocytogenes has received much attention and an impressive amount of data has contributed in raising this bacterium among the best understood intracellular pathogens. the mechanisms that listeria uses to enter cells, escape from the phagocytic vacuole and spread from one cell to another using an actin-based motility process have been analysed in detail. several bacterial proteins contributing to these events have been identified, inc ...19989669997
disseminated herpes simplex virus infection in a neonate.the emergency department (ed) evaluation of the neonate with sepsis or symptoms suggesting sepsis usually includes a complete blood count, catheterized urinalysis with culture, blood cultures, cerebrospinal fluid analysis and culture, and possibly a chest radiograph. admission for observation for neonates at high risk for sepsis is universal. depending on the patient's presentation and the preference of the admitting physician, intravenous antibiotics are started. typically, ampicillin and eithe ...19989672455
pathogenicity and immunogenicity of a listeria monocytogenes strain that requires d-alanine for growth.listeria monocytogenes is an intracellular bacterial pathogen that elicits a strong cellular immune response following infection and therefore has potential use as a vaccine vector. however, while infections by l. monocytogenes are fairly rare and can readily be controlled by a number of antibiotics, the organism can nevertheless cause meningitis and death, particularly in immunocompromised or pregnant patients. we therefore have endeavored to isolate a highly attenuated strain of this organism ...19989673233
the role of protegrins and other elastase-activated polypeptides in the bactericidal properties of porcine inflammatory fluids.the mammalian host response to infection includes the production and secretion of antimicrobial peptides from phagocytes and epithelial cells. protegrins, a group of broadly microbicidal peptides isolated originally from porcine neutrophil lysates, were found to be stored as inactive proforms in porcine neutrophil granules but could be activated extracellularly by neutrophil elastase. we assessed the biological role of protegrins and other elastase-activated polypeptides in the microbicidal acti ...19989673240
regulation of hly expression in listeria monocytogenes by carbon sources and ph occurs through separate mechanisms mediated by prfa.expression of the prfa-controlled virulence gene hly (encoding the pore-forming cytolysin listeriolysin) is under negative regulation by readily metabolized carbon sources in listeria monocytogenes. however, the hyperhemolytic strain nctc 7973 exhibits deregulated hly expression in the presence of repressing sugars, raising the possibility that a defect in carbon source regulation is responsible for its anomalous behavior. we show here that the activity of a second glucose-repressed enzyme, alph ...19989673243
listeria monocytogenes stimulates mucus exocytosis in cultured human polarized mucosecreting intestinal cells through action of listeriolysin o.when the intracellular pathogen listeria monocytogenes infects cultured human mucosecreting polarized ht29-mtx cells apically, it induces the stimulation of mucus exocytosis without cell entry. using a set of isogenic mutants and purified listeriolysin o (llo), we identified the l. monocytogenes thiol-activated exotoxin llo as the agonist of mucus secretion. we demonstrated that the llo-induced mucus exocytosis did not result from the llo membrane-damaging activity. we found that llo-induced muc ...19989673248
interactions of the invasive pathogens salmonella typhimurium, listeria monocytogenes, and shigella flexneri with m cells and murine peyer's patches.invasive enteric bacteria must pass through the intestinal epithelium in order to establish infection. it is becoming clear that a common target for intestinal mucosa penetration is the specialized epithelial cell of peyer's patches, the m cell. in order to gain a better understanding of how bacteria interact with m cells, we have compared the interactions of salmonella typhimurium, listeria monocytogenes, and shigella flexneri with m cells by using a murine ligated-loop model. our results indic ...19989673259
gelsolin, a protein that caps the barbed ends and severs actin filaments, enhances the actin-based motility of listeria monocytogenes in host cells.the actin-based motility of listeria monocytogenes requires the addition of actin monomers to the barbed or plus ends of actin filaments. immunofluorescence micrographs have demonstrated that gelsolin, a protein that both caps barbed ends and severs actin filaments, is concentrated directly behind motile bacteria at the junction between the actin filament rocket tail and the bacterium. in contrast, capg, a protein that strictly caps actin filaments, fails to localize near intracellular listeria. ...19989673261
molecular typing of listeria monocytogenes isolated in japan by pulsed-field gel electrophoresis.a total of 40 strains of listeria monocytogenes which have been demonstrated to be serovar 1/2a, 1/2b, and 4b were genotyped by pulsed-field gel electrophoresis (pfge) after separate digestion with apa i, asc i, sma i, and sse 8387 i. twenty-seven unrelated strains including four representative strains showed distinctly different genotypes according to their pfge profiles. then nine strains isolated from shredded cheese of different lots and four strains isolated from the cheese-processing envir ...19989673950
bacteriocin inhibition of two glucose transport systems in listeria monocytogenes.listeria monocytogenes transports glucose by proton motive force-mediated and phosphoenolpyruvate-dependent phosphotransferase systems (pep-dependent pts). inhibition of both systems by nisin, pediocin jd and leuconosin s is reported here for four strains of l. monocytogenes. intracellular and extracellular adenosine triphosphate (atp) and extracellular inorganic phosphate were measured in energized l. monocytogenes scott a cells to determine whether inhibition of the pep-dependent pts might occ ...19989674123
effect of oxygen concentration and redox potential on recovery of sublethally heat-damaged cells of escherichia coli o157:h7, salmonella enteritidis and listeria monocytogenes.the measured heat resistance of cells of escherichia coli o157:h7, salmonella enteritidis and listeria monocytogenes was up to eightfold greater when they were grown, heated and recovered anaerobically rather than aerobically. measured heat resistance was highest when anaerobic gas mixtures were used (time at 59 degrees c for a 6-decimal (6-d) reduction of e. coli o157:h7, 19-24 min); moderate when low concentrations of oxygen (0.5-1%) were included (time for a 6-d reduction, 5-17 min); and lowe ...19989674145
reducing total aerobic counts and listeria monocytogenes on the surface of king salmon (oncorhynchus tshawytscha).a trial industrial-scale fin-fish washing system was assessed for its effectiveness in removing bacteria associated with the skin of gilled and gutted king salmon (oncorhynchus tshawytscha). exposure of the salmon to 200 ppm free chlorine at a turnover rate for the total volume of the wash solution of 2.25 cycles h-1 for 120 min resulted in decreases in the aerobic plate count (apc) recovered from the salmon ranging from 96.6 to 99.2%. in order to optimize the washing regime a laboratory-scale f ...19989678168
heat stability of virulence-associated enzymes from listeria monocytogenes slcc 5764.the enzyme activities of listeriolysin o (llo), phosphatidylinositol-specific phospholipase c (pi-plc), catalase (ca), and superoxide dismutase (sod) from listeria monocytogenes slcc 5764 were examined after heat treatment, growth at elevated temperatures, and anaerobic growth. growth at elevated temperatures may influence virulence as expressed by virulence enzyme activity. the enzymes were heated for 0 and 10 min at temperatures ranging from 40 to 100 degrees c. the production of llo was exami ...19989678177
differential chemokine response of murine macrophages stimulated with cytokines and infected with listeria monocytogenes.during inflammatory processes the infected macrophage is a rich source of chemokines which induce infiltration of leukocytes to the site of infection. we investigated the regulation of chemokine production by murine macrophages in response to infection with the intracellular bacterial pathogen, listeria monocytogenes. as a source of quiescent macrophages, murine bone marrow-derived macrophages (bmm) cultured under serum-free conditions were used. with rt-pcr, we detected induction of rna message ...19989678756
listeriolysin o: cholesterol inhibits cytolysis but not binding to cellular membranes.listeriolysin o (llo) binds to cholesterol-containing membranes in which it oligomerizes to form pores. preincubation of the toxin with cholesterol is known to inhibit haemolysis, whereas the oxidized form of cholesterol has no inhibitory effect. using immunoblot analyses and flow cytometry we demonstrate that preincubation with cholesterol does not influence binding of the listeriolysin-cholesterol complex to red blood cells, eukaryotic cells or artificial membranes. lytic activity of membrane- ...19989680200
specificity of the bax polymerase chain reaction system for detection of the foodborne pathogen listeria monocytogenes.the polymerase chain reaction (pcr) can be used for rapid and specific detection of foodborne pathogens. one commercial kit, the qualicon bax system uses pcr to detect listeria monocytogenes in enrichment cultures derived from food and environmental samples. the specificity and sensitivity of the bax system for detecting l. monocytogenes were characterized by using both pure and mixed cell cultures, and optimal conditions for production of cell lysates were determined. the bax system was highly ...19989680707
control of il-12 and ifn-gamma production in response to live or dead bacteria by tnf and other factors.when mice were infected i.v. with either listeria monocytogenes or brucella abortus, bioactive il-12 was briefly detected in serum and supernatants of spleen homogenates immediately ex vivo. although the time scale was more prolonged for the more slowly growing b. abortus, in both instances il-12 production ceased while bacteria still persisted in high numbers. production of il-12, detected in serum and spleen, was neither increased nor prolonged by injecting abs to il-10 or il-4. in contrast wi ...19989686610
unstable expression and thermal instability of a species-specific cell surface epitope associated with a 66-kilodalton antigen recognized by monoclonal antibody em-7g1 within serotypes of listeria monocytogenes grown in nonselective and selective broths.conditions that resulted in unstable expression and heat instability of a cell surface epitope associated with a 66-kda antigen in listeria monocytogenes serotypes were identified with the probe monoclonal antibody (mab) em-7g1 in an enzyme-linked immunosorbent assay. this epitope appeared to be absent in three serotypes (serotypes 3b, 4a, and 4c), which did not react with mab em-7g1 irrespective of the enrichment broth tested. the remaining 10 serotypes were detected by mab em-7g1 only when cel ...19989687476
[the roles of heat shock proteins in host defense against bacterial infection].heat shock proteins (hsp) are widely distributed in nature, and are highly conserved proteins among prokaryotes and eukaryotes. these proteins are known to be involved in cytoprotection against various stress conditions including bacterial infection, and immune responses to various pathogens such as bacteria. in this study, we showed that hsp70 protected macrophages infected with salmonella choleraesuis against tnf-alpha-induced cell death. furthermore, hsp70-reactive cd4+ t cells appeared durin ...19989691765
perinephric abscess (presenting as abdominal pain) due to listeria monocytogenes.a 5-year-old malnourished child was admitted with a 1-week history of paroxysmal abdominal pain. evaluation finally revealed a left-sided perinephric abscess caused by listeria monocytogenes. the child was successfully treated by drainage of the abscess and antibiotic therapy. renal abscess should be kept in mind in the differential diagnosis of abdominal pain, and listeria, an unusual pathogen, should be considered as a possible aetiology.19989692004
septic arthritis with listeria monocytogenes during low-dose methotrexate.we describe a 22-year-old female with systemic lupus erythematosus and lymphopenia, who developed septic arthritis of the right knee with listeria monocytogenes type 1/2 a, whilst on low-dose methotrexate (mtx). so far, septic arthritis due to this microorganism has been reported in two other patients treated with low-dose mtx, one having rheumatoid arthritis and the other psoriatic arthritis. no reports exist on patients treated with other cytotoxic antirheumatic therapies.19989698030
effects of ph or a(w) stress on growth of listeria monocytogenes.the growth of three strains of listeria monocytogenes at 20 degrees c in a meat broth of different ph or water activity was investigated. at inoculation or at the beginning of the exponential phase, cells were exposed to stress by the addition of naoh or nh4+, acetic acid, nacl or kcl, in order to reach a ph of either 9.0 or 5.6, or an a(w) of 0.950 or 0.965, respectively. the effects of the exposure to stress on the generation and lag times of each strain were analysed by turbidity measurements ...19989706800
inhibition of listeria monocytogenes in a pork product by a lactobacillus sake strain.a lactobacillus sake strain (l. sake 2a), isolated from brazilian sausage ('lingüiça'), possessed antilisterial activity. the inhibitory activity observed in culture media was due to a proteinaceous compound, as demonstrated by the sensitivity to proteolytic enzymes. inhibition due to hydrogen peroxide, organic acids and lytic bacteriophages was ruled out. the inhibition of listeria monocytogenes by l. sake 2a was also demonstrated in laboratory-prepared 'lingüiça'. after four weeks at 8 degrees ...19989706804
prevalence and growth of listeria monocytogenes in naturally contaminated seafood.listeria monocytogenes contamination of seafood varies with product category. the highest prevalence was found in cold-smoked fish (34-60%), while the lowest was found in heat-treated and cured seafood (4-12%). the prevalence of l. monocytogenes differed greatly in cold-smoked salmon between production sites, ranging from < 1.4% (nil out of 70 samples) to 100%. the prevalence at the individual production sites was reproducible at repeated sampling. the results indicate that it is possible to pro ...19989706805
administration of killed bacteria together with listeriolysin o induces protective immunity against listeria monocytogenes in mice.it is known that only listeriolysin o (llo)-producing listeria monocytogenes strains are able to induce protective immunity, but the underlining relationship between llo produced by virulent strains and generation of protective immunity in the infected host remains poorly understood. in the present study, it was found that llo gene expression was only detected in the mice infected with virulent strain which was able to induce protective immunity, while non-virulent strains or killed bacteria wer ...19989708181
bacterial growth in ground beef patties made with meat from animals fed diets without or with supplemental vitamin e.a study was designed to determine populations of aerobic bacteria, coliforms, sorbitol-negative bacteria, and listeria monocytogenes during display at 4 and 12 degrees c of ground beef patties made with meat from animals fed diets supplemented daily (for 100 days) with 0, 1,000, or 2,000 iu of vitamin e. the patties (113.5 g) were either left uninoculated or were inoculated with escherichia coli o157:h7 or l. monocytogenes and were tray-overwrapped and stored (at 4 or 12 degrees c for 8 to 10 or ...19989708250
time and temperature of stretching as critical control points for listeria monocytogenes during production of mozzarella cheese.different heating times and temperatures commonly used during curd stretching were investigated to determine their effects on the viability of listeria monocytogenes in mozzarella cheese. pasteurized whole milk was inoculated with two levels of l. monocytogenes (7 and 3 log cfu/g) and coagulated with citric acid and rennet. the curd was stretched at 55, 66, and 77 degrees c for 1, 3, and 5 min. results indicated that the majority of l. monocytogenes cells remained in the cheese curds at both ino ...19989708265
inactivation of listeria innocua inoculated in liquid whole egg by high hydrostatic pressure.the resistance of listeria innocua, as a model microorganism for listeria monocytogenes, to high hydrostatic pressure in liquid whole egg was studied at several pressures (300, 350, 400, and 450 mpa),temperatures (- 15, 2, and 20 degrees c), and times (5, 10, and 15 min). listeria innocus was added to liquid whole egg at approximately 10(6) cfu/ml. listeria innocua was not totally inactivated in any of the treatments. in general, reduction was better at 2 degrees than at room temperature, but th ...19989708266
inhibition of listeria monocytogenes in a smear-surface soft cheese by lactobacillus plantarum whe 92, a pediocin ach producer.the anti-listeria monocytogenes activity of lactobacillus plantarum whe 92, a pediocin ach producer, was investigated in munster cheese, a smear-surface soft cheese. the appearance of l. monocytogenes in the cheese, which naturally occurs solely in the crust and never before 1 week of ripening, could be prevented by spraying a cell suspension of l. plantarum whe 92 (ca. 10(5) cfu/ml) on the cheese surface at the beginning of the ripening period. l. monocytogenes was sometimes detected at low lev ...19989708279
changes in populations of listeria monocytogenes inoculated on packaged fresh-cut vegetables.a variety of wholesale and retail packaged vegetables and salads were inoculated with a mixture of strains of listeria monocytogenes and incubated at 4 and 10 degrees c. whole rutabagas, butternut squash, and onions, as well as packaged caesar salad, carrots, coleslaw mix, and stir-fry vegetables were purchased from local supermarkets in the ottawa area. l. monocytogenes population levels remained constant on all fresh-cut vegetables stored at 4 degrees c for 9 days, except for carrots and butte ...19989708280
indicative and pathogenic microbiological quality of aquacultured finfish grown in different production systems.the nature and number of indicator and pathogenic microbes in fish reared using recirculating and nonrecirculating water systems were compared. for each system, 20 samples of rainbow trout (oncorhynchus mykiss), tilapia (oreochromis spp.), hybrid striped bass (morone saxatilis x m. chrysops), and pacu (piaractus mesopotamicus) were randomly selected and gutted, and microbial analyses were performed using aoac procedures. five fish were subsampled and analyzed for indicative microbial quality wit ...19989708283
studies on the risk assessment of listeria monocytogenes.humans are frequently exposed to listeria monocytogenes, and high numbers may be ingested during consumption of certain types of food. however, epidemiological investigations show that listeriosis is a rare disease. risk assessment studies using an animal mouse model indicate that almost all l. monocytogenes serovars present in food have clear virulent properties. the intravenous dose causing infection in 50% (iv id50) of mice not previously exposed to l. monocytogenes (nonprotected mice) was 1. ...19989708290
survival of bacterial pathogens in pasteurized process cheese slices stored at 30 degrees c.six lots of commercial pasteurized process cheese slices were evaluated for the ability to support the growth of four foodborne pathogens, listeria monocytogenes, staphylococcus aureus, salmonella serotypes, and escherichia coli o157:h7, during 4 days of storage at 30 degrees c. individual cheese slices were inoculated separately with each pathogen to yield ca. 10(3) cfu/g. slices were packaged in sterile plastic sample bags and stored at 30 degrees c for up to 96 h. population of salmonella ser ...19989708298
fate of bacterial pathogens and indicator organisms in liquid sweeteners.the survival of pathogenic and indicator microorganisms in liquid sweeteners was studied. seven sweeteners--liquid sucrose, 42% high-fructose corn syrup (hfcs), 55% hfcs, 25 de (dextrose equivalent) corn syrup (cs), 36 de cs, 63 de cs, 50% medium invert sucrose, and 65% high-maltose corn syrup (hmcs) were inoculated with salmonella spp., listeria monocytogenes, staphylococcus aureus, escherichia coli, pseudomonas aeruginosa, and coliforms at a level of 10(5) cells per g. the inoculated products ...19989708299
inhibition of listeria monocytogenes and aeromonas hydrophila by plant extracts in refrigerated cooked beef.refrigerated ready-to-eat foods are becoming increasingly popular but are often vulnerable to contamination and subsequent growth by psychrotrophic foodborne pathogens. consequently, there is a need for additional methods to assure the safety of these foods. beef slices prepared from roasted whole sirloin tips were used in the study. nine plant extracts were evaluated for ability to inhibit the growth of two psychrotrophic pathogens (aeromonas hydrophila and listeria monocytogenes) in refrigerat ...19989708301
growth of inoculated psychrotrophic pathogens on refrigerated fillets of aquacultured rainbow trout and channel catfish.aquacultured rainbow trout (oncorhynchus mykiss) and channel catfish (ictalurus punctatus) fillets were inoculated with the psychrotrophic pathogens listeria monocytogenes and aeromonas hydrophila: cell populations were monitored during refrigerated storage at 2 to 4 degrees c. fillets of both species were placed individually in sterile plastic bags and inoculated with cell suspensions (10(4.7) cfu/100 g of fish) of either a. hydrophila or l monocytogenes or of both a. hydrophila and l. monocyto ...19989708302
the incidence of listeria spp., salmonella spp., and clostridium botulinum in smoked fish and shellfish.the frequency of occurrence of listeria spp., salmonella spp., and clostridium botulinum is samples of smoked finfish and smoked shellfish was analyzed over a 5-year period. listeria monocytogenes were isolated from 14% of 1,080 samples. for those samples where the smoke process was known, the incidence of l. monocytogenes was higher in cold-smoked than hot-smoked products (51 of 240 cold-smoked compared to 19 of 215 hot-smoked products). listeria species other than l. monocytogenes were also de ...19989708303
incidence of listeria monocytogenes in cheese produced in rio de janeiro, brazil.the present study evaluated the incidence of listeria spp. in some brazilian cheeses obtained from retail stores in rio de janeiro, of 103 samples of various types of cheese examined as recommended in the listeria isolation protocol of the health protection branch of canada, 11 (10.68%) were contaminated by listeria monocytogenes, 13 (12.62%) by listeria innocua, 6 (5.83%) by listeria grayi, and 1 (0.97%) by listeria welshimeri. a higher incidence of l. monocytogenes as observed mainly in the ho ...19989708310
listeriosis in pediatric oncology patients.adult cancer patients are considered to be at an increased risk for listeria monocytogenes infections, but, to the authors' knowledge, little information regarding this infection in the pediatric oncology population has been published.19989708951
interaction of hydrostatic pressure, time and temperature of pressurization and pediocin ach on inactivation of foodborne bacteria.high hydrostatic pressure, because it can kill microorganisms, is being investigated for potential use as a nonthermal food preservation method. the objective of this study was to determine the hydrostatic pressurization parameters, pressure, time, and temperature, and a bacteriocin that in combination would destroy 7 to 8 log cycles of pathogenic and spoilage bacterial populations. we suspended cells of staphylococcus aureus, listeria monocytogenes, salmonella typhimurium, escherichia coli o157 ...19989709205
microbiological quality of australian beef carcass meat and frozen bulk packed beef.two studies were undertaken to determine the microbiological of beef carcass meat and frozen boneless bulk packed beef produced in australia. samples were collected from 1,063 beef carcasses and from 929 cartons of frozen boneless bulk packed beef over a period of approximately 12 months. samples were collected from works processing beef carcasses for the australian domestic market and from works targeting export markets. on carcasses processed for export markets, where bacterial counts were obt ...19989709207
duplex (thermotroph-psychrotroph) quadrant plates: convenient, error-avoiding tools for monitoring of haccp-contained food lines and for epidemiological investigations under conditions of military or other constraints.a set of two "two-tier" (thermotroph-psychrotroph) single quadrant plates (qps) was developed previously to allow convenient enumeration of numbers of colony-forming units of most pertinent pathogenic bacteria or marker bacteria in foods. these include listeria monocytogenes, staphylococcus aureus, bacillus cereus, thermotrophic and psychrotrophic enterobacteriaceae, clostridium spp., and enterococcus spp. as the qps had given excellent results in monitoring samples of marketed food products pot ...19989709209
an efficient sampling technique used to detect four foodborne pathogens on pork and beef carcasses in nine belgian abattoirs.the method presented in this paper should prove useful in assessing the effectiveness of haccp plans developed in slaughterhouses. samples were collected by swabbing well-defined areas of pork and beef carcasses with sterile gauze. between 160 and 420 half-carcasses were swabbed in each of nine pork or beef slaughterhouses. swabs from five carcasses were placed in the same sterile stomacher bag, constituting a single composite sample. standard or validated analytical methods were used to isolate ...19989709223
growth and survival of listeria monocytogenes in vacuum-packaged ground beef inoculated with lactobacillus alimentarius floracarn l-2.a culture of the psychotrophic strain floracarn l-2 of lactobacillus alimentarius was added to ground beef (ph 5.4) inoculated with two isolates of listeria monocytogenes able to grow in refrigerated ground beef. the ground beef was vacuum-packaged and stored for 9 weeks at 4 degrees c. populations of inoculated l. monocytogenes initially were 6.3 to 6.4 log10 cfu/g and increased to 7.4 log10 cfu/g in ground beef with no added lactobacilli. addition of l. alimentarius l-2 or its antibiotic-resis ...19989709226
recovery of foodborne microorganisms from potentially lethal radiation damage.a two-stage recovery protocol was examined for microorganisms following gamma irradiation in phosphate buffer at 0 degrees c. in the first stage, survivors were recovered on basal yeast extract agar and held at various temperatures suboptimal for their growth for 20 h (resuscitation protocol). in the second stage the survivors were incubated for an additional 24 h, but in this case at their optimum temperature for growth. controls consisted of survivors which were not subjected to the resuscitat ...19989709232
heat resistance and fatty acid composition of listeria monocytogenes: effect of ph, acidulant, and growth temperature.the objective of this study was to determine the influence of ph, acidulant, and growth temperature history on the heat resistance and fatty acid composition of listeria monocytogenes scott a. cells were grown to late exponential phase (od600 = 0.6) at 10, 19, or 37 degrees c in brain heart infusion broth acidified to ph 5.4 or 7 with either acetic or lactic acid. thermal death times at 60 degrees c subsequently were determined by using a submerged-coil heating apparatus. the surviving cell popu ...19989709249
chemical and bacteriological characteristics of pichtogalo chanion cheese and mesophilic starter cultures for its production.sixty-two samples of pichtogalo chanion cheese traditionally produced in crete, a few (3 to 6) days old, were analyzed for some chemical and bacteriological characteristics. the results of physicochemical analyses were as follows: (1) moisture content 61.63% (standard deviation 4.67); (2) fat in dry matter 54.03% (sd 7.73); (3) protein content 14.23% (sd 1.72); (4) salt content 1.02% (sd 0.38); (5) water activity (aw) 0.990 (sd 0.003); and (6) ph 4.36 (sd 0.25). none of the samples yielded salmo ...19989709250
effect of several decontamination procedures on listeria monocytogenes growing in biofilms.listeria monocytogenes is a pathogenic bacterium which has been implicated in several foodborne illnesses. this microorganism grows into biofilms attached to the surfaces in food-processing plants, increasing its resistance to antimicrobial agents. the present work was realized to investigate the attachment of l. monocytogenes isolates to glass surfaces and to find a decontamination procedure to remove these bacteria in biofilms. three-day biofilms were prepared by growing l. monocytogenes isola ...19989709259
human macrophages induced in vitro by macrophage colony-stimulating factor are deficient in il-12 production.il-12 is important for th1 differentiation. myeloid-derived antigen-presenting cells (apc) such as monocytes, macrophages (mphi) and dendritic cells (dc) are believed to be major sources of il-12 in vivo. we have compared il-12 production of fresh monocytes with mphi differentiated in vitro using macrophage colony-stimulating factor (m-csf) or human plasma, and in vitro generated dendritic cells, since these differentiated cell types represent apc at sites of antigen challenge. macrophages stimu ...19989710227
survival of bioluminescent listeria monocytogenes and escherichia coli o157:h7 in soft cheeses.pasteurized and raw milks that had been inoculated at 10(4) cfu/ml with bioluminescent strains of listeria monocytogenes and escherichia coli o157:h7 were used in the manufacture of camembert and feta cheeses with or without nisin-producing starter culture. survival of both organisms was determined during the manufacture and storage of camembert and feta cheeses at 2 +/- 1 degree c for 65 and 75 d, respectively. bacterial bioluminescence was used as an indicator to enumerate the colonies plated ...19989710748
listeria monocytogenes in the colon in a case of fulminant ulcerative colitis.a case of ulcerative colitis in which the presence of listeria monocytogenes was confirmed in the resected colon with polymerase chain reaction and subsequent southern blot analysis and immunohistochemistry using antibody against listeria is presented. the patient developed ulcerative colitis at the age of 59 years. prednisolone, 50 mg/day, was given for severe ulcerative colitis. later the disease became fulminating, indicating colectomy 4 months after the onset. multiple sealed colonic perfora ...19989712246
effect of siderophores, catecholamines, and catechol compounds on listeria spp. growth in iron-complexed medium.almost all bacteria require iron for growth and virulence expression. however, listeria spp. do not produce any siderophore for iron acquisition. representative strains of each of the six species of listeria were examined for their ability to use various compounds as iron suppliers in iron-restricted medium. here we show that l. monocytogenes, l. innocua, l. ivanovii, l. welshimeri, l. seeligeri, and l. grayi were able to use exogenous siderophores and various catechol ligands, including catecho ...19989712730
the contributions of reactive oxygen intermediates and reactive nitrogen intermediates to listericidal mechanisms differ in macrophages activated pre- and postinfection.the contribution of reactive oxygen intermediates (roi) and reactive nitrogen intermediates (rni) to the killing of listeria monocytogenes by macrophages activated by addition of spleen cells from listeria-immune mice plus specific antigen was examined. when macrophages were infected with l. monocytogenes and then spleen cells were added, there was not as big a difference in listericidal activity between macrophages cultured with normal spleen cells and those cultured with immune spleen cells as ...19989712745
fas (cd95)-dependent cell-mediated immunity to listeria monocytogenes.two distinct and complementary pathways, one mediated by perforin and the other dependent upon cd95 (fas), effect cell-mediated cytotoxicity. we examined the relative roles of these pathways in host defenses against the intracellular bacterial pathogen listeria monocytogenes by using murine listeriosis as a model system. mice which lacked both perforin and fas (p0l0) were generated, and their responses to primary and secondary listeriosis were compared to those of wild-type (wt), fas-deficient ( ...19989712760
entry of listeria monocytogenes into neurons occurs by cell-to-cell spread: an in vitro study.listeria monocytogenes is an intracellular pathogen that causes severe central nervous system infection in humans and animals. the ability of this bacterium to penetrate nerve cells was investigated by using rat spinal cell cultures. entry into distinct cell types, i. e., glial cells and neurons, was monitored by a differential immunofluorescence technique with antibodies against cell type-specific markers and the bacterial pathogen. l. monocytogenes was detected predominantly within macrophages ...19989712801
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