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cloning and genetic organization of the bacteriocin 31 determinant encoded on the enterococcus faecalis pheromone-responsive conjugative plasmid pyi17.the conjugative plasmid pyi17 (57.5 kb) isolated from enterococcus faecalis yi717 confers a pheromone response on the host and encodes the bacteriocin 31 gene. bacteriocin 31 is active against e. hirae 9790, e. faecium, and listeria monocytogenes. pyi17 was mapped physically by restriction enzyme analysis and the relational clone method. deletion mutant and sequence analyses of the ecori fragment b cloned from pyl17 revealed that a 1.0-kb fragment contained the bacteriocin gene (baca) and an imm ...19968655558
multilocus enzyme electrophoresis typing of new zealand listeria monocytogenes isolates.eighty-five strains of listeria monocytogenes, comprising 74 strains isolated from the environment, humans, animals and foods in new zealand; 10 strains from similar sources in denmark, and one reference strain, were studied using multilocus enzyme electrophoresis (mee). fifty-five electrophoretic types (ets) were identified among the 85 strains, most (71%) of which were represented by only one isolate. the 74 new zealand isolates produced 45 ets, most (67%) of which were represented by only one ...19968652343
automated rna probe assay for the identification of listeria monocytogenes.recent epidemics of human listeriosis have shown the importance of listeria monocytogenes as a food-borne risk. we have developed an automated identification assay for l. monocytogenes using the specificity of the 16s rdna probe described by wang et al. (1991). bacterial cultures were lysed quickly by a chemical step releasing the target nucleic acids. extracts were loaded into the vidas automate (biomérieux) which performed a non-radio-active hybridisation reaction for 2 h. this assay recognise ...19968652341
peripheral blood gamma delta t cells in human listeriosis.a phenotypical analysis carried out by direct immunofluorescence and two-colour cytofluorometry showed that the number of lymphocytes bearing the gamma delta t-cell receptor heterodimer was increased in the blood of eight children with listeria monocytogenes infection, mainly due to an expansion of cells identified by monoclonal antibodies which recognize v delta 2 gene products. these findings are further evidence that gamma delta t cells are in some way involved in the immune response directed ...19958645966
superior efficacy of secreted over somatic antigen display in recombinant salmonella vaccine induced protection against listeriosis.vaccination provides the most potent measure against infectious disease, and recombinant (r) viable vaccines expressing defined pathogen-derived antigens represent powerful candidates for future vaccination strategies. in a new approach we constructed r-aroa- salmonella typhimurium displaying p60 or listeriolysin (hly) antigen of listeria monocytogenes in secreted or somatic form in the host cell. vaccination of mice with r-aroa- s. typhimurium induced protection against the intracellular pathog ...19968643654
effect of pre- and post-heat shock temperature on the persistence of thermotolerance and heat shock-induced proteins in listeria monocytogenes.the effect of incubation temperature, before and after a heat shock, on thermotolerance of listeria monocytogenes at 58 degrees c was investigated. exposing cells grown at 10 degrees c and 30 degrees c to a heat shock resulted in similar rises in thermotolerance while the increase was significantly higher when cells were grown at 4 degrees c prior to the heat shock. cells held at 4 degrees c and 10 degrees c after heat shock maintained heat shock-induced thermotolerance for longer than cells hel ...19968642016
epidemiologic evaluation of encephalitic listeriosis in goats.to evaluate host and environmental factors associated with the development of encephalitic listeriosis in goats.19968641953
identification and purification of novel internalin-related proteins in listeria monocytogenes and listeria ivanovii.monoclonal antibodies were generated against a 30-kda protein fraction derived from culture supernatants of a listeria monocytogenes strain complemented with additional copies of the prfa regulator gene. several of the antibodies reacted specifically with a hitherto unidentified, secreted 30-kda polypeptide. by immunoblot analysis, the expression of this 30kda polypeptide was found to be dependent on the presence of the prfa regulator protein. microsequencing of peptides derived from the partial ...19968641748
in vitro conjugative transfer of vana vancomycin resistance between enterococci and listeriae of different species.in a study designed to gain data on the in vitro transferability of vancomycin resistance from enterococci of the vana phenotype to listeriae of different species, three clinical enterococcus isolates-enterococcus faecium ls10, enterococcus faecalis ls4, and enterococcus faecalis a3208, all harboring a plasmid that strongly hybridized with a vana probe-were used as donors in transfer experiments. strains of five listeria species were used as recipients. from enterococcus faecium ls10, glycopepti ...19968641304
the effects of inhibitors of vacuolar acidification on the release of listeria monocytogenes from phagosomes of caco-2 cells.to evaluate the role of the acidic ph of phagosomes on the invasive ability and fate of listeria monocytogenes within host cells, entry and replication of this gram-positive bacterium in a human enterocyte-like cell line (caco-2) were investigated by a combination of biochemical and ultrastructural approaches. the effects of inhibitors of vacuolar acidification--the lipophilic weak base ammonium chloride, the carboxylic ionophore monensin and the vacuolar proton atpase inhibitor bafilomycin a1-- ...19968636958
recovery of different listeria ribotypes from naturally contaminated, raw refrigerated meat and poultry products with two primary enrichment media.isolation rates for listeria monocytogenes and the other listeria spp. typically improve when samples are enriched in more than one primary enrichment medium. this study evaluated the abilities of two primary enrichment media, university of vermont-modified listeria enrichment broth (uvm) and listeria repair broth (lrb), to recover different ribotypes of listeria spp. from raw meat and poultry samples. forty-five paired 25-g retail samples of ground beef, pork sausage, ground turkey, and chicken ...19968633878
adaptive acid tolerance response in listeria monocytogenes: isolation of an acid-tolerant mutant which demonstrates increased virulence.the ability of listeria monocytogenes to tolerate low-ph environments is of particular importance because the pathogen encounters such environments in vivo, both during passage through the stomach and within the macrophage phagosome. in our study, l. monocytogenes was shown to exhibit a significant adaptive acid tolerance response following a 1-h exposure to mild acid (ph 5.5), which is capable of protecting cells from severe acid stress (ph 3.5). susceptibility to ph 3.5 acid is growth phase de ...19968633868
delivery of macromolecules into cytosol using liposomes containing hemolysin from listeria monocytogenes.the cytosolic space of cells is an important but relatively inaccessible target for the delivery of therapeutic macromolecules. here we describe the efficient delivery of macromolecules into the cytosolic space of macrophages from liposomes that contain listeriolysin o (llo), the hemolytic protein of listeria monocytogenes that normally mediates bacterial passage from phagosomes into cytosol. llo was purified and encapsulated inside ph-sensitive liposomes, along with other molecules to be delive ...19968631734
effects of ultraviolet-b exposure on the resistance to listeria monocytogenes in the rat.a rat infection model using the bacterial pathogen listeria monocytogenes was employed to analyze the immunosuppressive activity of uvb radiation. rats were exposed to suberythemal doses of uvb radiation for 5 or 7 consecutive days, using kromayer or fs40 lamps respectively. subsequently, the rats were infected subcutaneously or intravenously with listeria. exposure to uvb resulted in an increased number of bacteria in the spleen 4 days after infection. listeria-specific lymphocyte proliferation ...19968628759
antiviral cytotoxic t-cell memory by vaccination with recombinant listeria monocytogenes.listeria monocytogenes is a facultative intracellular bacterium that is able to escape phagocytic vesicles and replicate in the cytoplasm of infected cells. as with viral vectors, this intracytoplasmic life cycle provides a means for introducing foreign proteins into the major histocompatibility complex class i pathway of antigen presentation. using recombinant l. monocytogenes (rlm) strains expressing the full-length nucleoprotein (np) or a single cytotoxic t-lymphocyte (ctl) epitope from lymph ...19968627765
listeria monocytogenes meningoencephalitis: murine models vs. the naturally occurring disease in ruminants. 19968627350
the inlab locus mediates the entry of listeria monocytogenes into hepatocytes in vivo.the intracellular parasite listeria monocytogenes is able to induce its internalization by cultured mammalian cells that are not normally phagocytic. this process requires the expression of the chromosomal locus inlab. we studied the virulence of an inlab mutant and of its parent in murine listeriosis. irrespective of the route of inoculation, the inlab mutant was severely attenuated for growth in the liver. the livers of mice inoculated with the inlab mutant displayed much smaller infectious fo ...19968627149
safety evaluation of a polymerized hemoglobin solution in a murine infection model.several investigators have observed that free hemoglobin may increase the mortality rate in experimental escherichia coli peritonitis in animals. this effect is probably mediated by the heme moiety of hemoglobin, but the mechanism remains controversial. free hemoglobin might impair neutrophil function, and it might serve as a source of iron, which is necessary for bacterial replication. several modified hemoglobin solutions, developed as blood substitutes, are currently being tested in clinical ...19968621979
effects of amiodarone-induced phospholipidosis on pulmonary host defense functions in rats.the effect of the induction of pulmonary phospholipidosis by amiodarone on selected pulmonary host defense functions was studied in male fischer-344 rats. one week of daily amiodarone treatment resulted in a 4.5-fold increase in total phospholipid in alveolar macrophages recovered from the lungs by bronchoalveolar lavage. the presence of the phospholipidosis had no effect on the phagocytosis of heat-killed yeast cells, the induction of luminol-dependent chemiluminescence, or the spontaneous rele ...19968618940
stimulation of protective cd8+ t lymphocytes by vaccination with nonliving bacteria.infectious diseases caused by intracellular microbes are responsible for major health problems, and satisfactory control will ultimately depend on efficient vaccination strategies. the general assumption is that activation of protective immune responses against intracellular microbes dominated by cd8+ t cells are achieved only by live vaccines. in contrast, we here demonstrate stimulation of protective immunity in mice against the intracellular pathogen listeria monocytogenes by vaccination with ...19958618907
[listeria meningitis in adults]. 19968618625
salmonella typhimurium aroa- infection in gene-targeted immunodeficient mice: major role of cd4+ tcr-alpha beta cells and ifn-gamma in bacterial clearance independent of intracellular location.due to the dependency on aromatic precursors, the growth of salmonella typhimurium aroa- is limited in immunocompetent mice. here we show that h-21-a beta-/- mice (lacking mhc class ii molecules and thus devoid of mature cd4+ tcr-alpha beta cells), tcr-beta-/- mice (devoid of tcr-alpha beta cells), and ifn-gamma r-/- mice (unresponsive to ifn-gamma) are highly susceptible to s. typhimurium aroa- infection compared with heterozygous controls. in contrast, beta 2m-deficient mice (lacking surface m ...19968617956
administration of interleukin-10 abolishes innate resistance to listeria monocytogenes.we have used severe-combined immunodeficient (scid) mice to examine the immunoregulatory effects of interleukin (il)-10 on innate resistance to infection with listeria monocytogenes. addition of heat killed listeria to spleen cells from naive scid mice resulted in secretion of interferon (ifn)-gamma from natural killer cells in vitro. this response was enhanced up to 15-fold in the presence of exogenous il-2, but was completely ablated by addition of il-10 with ic50 of less than 0.5 u/ml. infect ...19968617304
peptide epitopes from noncytosolic listeria monocytogenes can be presented by major histocompatibility complex class i molecules.listeria monocytogenes is an intracellular pathogen which escapes the phagosome and resides in the cytosol of the host cell. using listeria innocua and a mutant strain of l. monocytogenes (listeriolysin o negative), which do not enter the cytosol of the host cell, we demonstrate class i presentation of an epitope of p60, a protein secreted by l. monocytogenes, to a class i-restricted cd8+ cytotoxic t lymphocyte clone.19968613407
control of natural killer cell-mediated innate resistance against the intracellular pathogen listeria monocytogenes by gamma/delta t lymphocytes.listeria monocytogenes is an intracellular bacterium which causes an acute infectious disease in mice. initial host resistance depends on innate immunity mediated primarily by natural killer (nk) cells followed by specific alpha/beta t cells, which are central to acquired specific immunity. gamma/delta t lymphocytes seem to provide a link between the innate and the specific immune response. all these lymphocyte populations produce gamma interferon (ifn-gamma), which, because of its macrophage-ac ...19968613386
a recombinant minigene vaccine containing a nonameric cytotoxic-t-lymphocyte epitope confers limited protection against listeria monocytogenes infection.we have previously shown that vaccines expressing virus-derived cytotoxic-t-lymphocyte (ctl) epitopes as short minigenes can confer effective protection against virus challenges, and here we extend these studies to the bacterium listeria monocytogenes. host defense against this important human pathogen appears largely t cell mediated, and a nonamer ctl epitope from the listeriolysin o (llo) protein has been identified in balb/c mice. we have synthesized this nonamer as a minigene, expressed it i ...19968613379
bacteroides fragilis enterotoxin modulates epithelial permeability and bacterial internalization by ht-29 enterocytes.enterotoxigenic bacteroides fragilis has been associated with diarrheal disease, and the enterotoxin has a cytopathic effect on cultured ht-29 enterocytes. experiments were designed to determine the effect of b. fragilis enterotoxin on bacteria-enterocyte interactions.19968613048
complement receptor type 3 mediates phagocytosis and killing of listeria monocytogenes by a tnf-alpha- and ifn-gamma-stimulated macrophage precursor hybrid.previous work demonstrated that engagement of complement receptor type 3 (cr3) was required for inflammatory peritoneal macrophages to phagocytose and kill the facultative intracellular bacterium listeria monocytogenes. the experiments described here tested the role of cr3 in phagocytosis and killing of listeria by a clonal population of tnf-alpha/ifn-gamma-stimulated macrophage precursor hybrids. stimulation with tnf-alpha and ifn-gamma increased cr3 expression 20-fold and induced a big increas ...19968612281
listeria monocytogenes arthritis of several joints.a patient with rheumatoid arthritis (ra) developed an infection caused by listeria monocytogenes in her left knee and both shoulder joints. the clinical presentation of the disease was rather indolent with relatively moderate joint symptoms. moreover, the synovial fluid sample was only slightly turbid with a white blood cell count of 23.5 x 10(9)/1. as compared to the earlier reported cases of l. monocytogenes septic arthritis, our patient is unique because she had infection in several joints. t ...19958610227
differential effects of viable and killed bacteria on il-12 expression of macrophages.listeria monocytogenes-specific, ifn-gamma-producing cd4+ t cells are induced in 5-day in vitro cultures of naive spleen cells with viable l. monocytogenes (vlm) but are not induced in cultures with heat killed l. monocytogenes (hklm). anti-il-12 abs abrogated the induction of the ifn-gamma-producing cd4+ t cells by vlm, suggesting an importance of il-12 in the induction of ifn-gamma-producing cd4+ t cells. accordingly, il-12p40 was expressed by macrophages (m phi) from the cultures of whole spl ...19968609419
early pathogenesis of listeria monocytogenes infection in the mouse spleen.histological observations suggested that in the spleen, blood-borne listeria monocytogenes bacteria were preferentially ingested by two morphologically distinct mononuclear phagocyte populations present in the marginal zone of the white pulp. the morphologies of these phagocytes corresponded to those of marginal zone macrophages or marginal zone dendritic cells. moreover, during the first day of infection, the same phagocytes containing listeria apparently translocated from the marginal zone int ...19968606358
effect of cell polarization and differentiation on entry of listeria monocytogenes into the enterocyte-like caco-2 cell line.the entry of listeria monocytogenes into the enterocyte-like caco-2 cell line was studied as a function of cell polarization and differentiation. l. monocytogenes entered through the entire surface of nonpolarized cells and, predominantly, through the basolateral surface of polarized cells based on the following observations: (i) sites of l. monocytogenes invasion paralleled the distribution of the transferrin receptor, a well-known basolateral marker of polarization; (ii) numbers of internalize ...19968606093
endogenous interleukin-4, but not interleukin-10, is involved in suppression of host resistance against listeria monocytogenes infection in interferon-depleted mice.the production and roles of endogenous interleukin-4 (il-4) and il-10 in a sublethal infection with listeria monocytogenes were studies in normal mice and anti-gamma interferon (ifn-gamma) monoclonal antibody (mab)-pretreated mice. in normal mice, the expression of mrnas for il-4 and il-10, which was amplified by reverse transcription-pcr, was induced in the spleens and livers either early or late in infection, although the serum il-4 and il-10 were not detectable by enzyme-linked immunosorbent ...19968606087
acquired resistance against a secondary infection with listeria monocytogenes in mice is not dependent on reactive nitrogen intermediates.during an infection, inflammatory mediators can induce the production of nitric oxide, a reactive nitrogen intermediate (rni) which plays a role in antimicrobial activity against a wide variety of pathogens. in vitro experiments have shown that release of rni by macrophages is mediated by tumor necrosis factor alpha (tnf). since tnf is essential for acquired resistance during a secondary listeria monocytogenes infection in mice, the aim of the present study was to determine whether rni are also ...19968606078
intramolecular inhibition of human defensin hnp-1 by its propiece.we examined mechanisms that protect host defense cells from their cytotoxic effector molecules. human neutrophil peptides (hnp) 1-3 are microbicidal and cytotoxic defensins, initially synthesized as 94-amino acid preprohnp(1-94), cotranslationally proteolyzed to prohnp(20-94), then converted by removal of the anionic propiece to mature hnp(65-94)(hnp-1 and -3) and hnp(66-94) (hnp-2). we hypothesized that during synthesis and subcellular sorting the anionic propiece inhibits the cytotoxicity of t ...19968601627
recognition of two classes of oligoproline sequences in profilin-mediated acceleration of actin-based shigella motility.the gram negative rod shigella flexneri uses it surface protein icsa to induce host cell actin assembly and to achieve intracellular motility. yet, the icsa protein lacks the oligoproline sequences found in acta, the surface protein required for locomotion of the gram positive rod listeria monocytogenes. microinjection of a peptide matching the second acta oligoproline repeat (fefpppptde) stops listeria locomotion (southwick, f.s., and d.l. purich. 1994a. proc. natl. acad. sci. usa. 91:5168-5172 ...19968601612
bacterial complications of transplantation: diagnosis and treatment.bacterial complications develop mainly after transplantation during the period before engraftment takes place. wound infections, urinary tract infection and pneumonia are the commonest complications of solid organ transplantation and generally involve gram-negative bacilli and staphylococcus aureus. however, gram-positive cocci will predominate when selective oral antimicrobial prophylaxis is given as is frequently the case in bone marrow transplant recipients. oromucositis, induced by total bod ...19958601544
e-cadherin is the receptor for internalin, a surface protein required for entry of l. monocytogenes into epithelial cells.we report the first identification of a cellular receptor mediating entry of a gram-positive bacterium into nonphagocytotic cells. by an affinity chromatography approach, we identified e-cadherin as the ligand for internalin, an l. monocytogenes protein essential for entry into epithelial cells. expression of the chicken homolog of e-cadherin (l-cam) in transfected fibroblasts dramatically increases entry of l. monocytogenes and promotes that of a recombinant l. innocua strain expressing interna ...19968601315
listeria rhombencephalitis: report of two cases with early diagnosis and favourable outcome.we present 2 cases of listeria monocytogenes rhombencephalitis (l-re), both affecting previously healthy adult men. each of them developed a diphasic syndrome first characterized by fever, nausea and headache, followed, in a second phase, by severe brain stem dysfunction at the level of the pons, with meningism, multiple cranial nerve palsies, ataxia, and, in one case, seizures. the early examination of the cerebrospinal fluid (csf) demonstrated the presence of gram-positive bacilli whose typica ...19958599906
enter listeria, unruffled. 19968596949
asymmetric distribution of the listeria monocytogenes acta protein is required and sufficient to direct actin-based motility.listeria monocytogenes is a gram-positive facultative intracytoplasmic bacterial pathogen that exhibits rapid actin-based motility in eukaryotic cells and in cell-free cytoplasmic extracts. the protein product of the acta gene is required for bacterial movement and is normally expressed in a polarized fashion on the bacterial surface. here we demonstrate that the acta protein is sufficient to direct motility in the absence of other l. monocytogenes gene products, and that polarized localization ...19958596443
use of molecular typing methods to trace the dissemination of listeria monocytogenes in a shrimp processing plant.molecular typing of bacteria has been widely used in epidemiological studies but not as extensively for tracing the transmission of pathogenic bacteria in food plants. this study was conducted to examine the potential use of two molecular typing methods, random amplified polymorphic dna (rapd) analysis and pulsed-field gel electrophoresis (pfge), to trace listeria monocytogenes contamination in a shrimp processing plant. ribotyping and phase typing were also performed on a select number of strai ...19968593073
physiochemical characterization of the nisin-membrane interaction with liposomes derived from listeria monocytogenes.mechanistic information about the bacteriocin nisin was obtained by examining the efflux of 5(6)-carboxy-fluorescein from listeria monocytogenes-derived liposomes. the initial leakage rate (percentage of efflux per minute) of the entrapped dye was dependent on both nisin and lipid concentrations. at all nisin concentrations tested, 5(6)-carboxyfluorescein efflux plateaued before all of the 5(6)-carboxyfluorescein was released (suggesting that pore formation was transient), but efflux resumed whe ...19968593036
intracellular pathogenesis of listeriosis. 19968592552
phenotypic characterization of the cells of the inflammatory response in ovine encephalitic listeriosis.the brainstem (pons cerebri and medulla oblongata) of 22 sheep aged between 6 months and 3 years which had developed clinical signs of central nervous system dysfunction were examined. histopathological changes characterized by microabscesses, focal gliosis and perivascular cuffing compatible with natural infection with listeria monocytogenes were present. the brains were examined by lectin histochemistry and immunohistochemistry with markers for t lymphocytes (cd4+ and cd8+ subsets), b lymphocy ...19958592052
hyperexpression of listeriolysin in the nonpathogenic species listeria innocua and high yield purification.listeriolysin, the hemolysin of the pathogenic species listeria monocytogenes, was expressed in the non-pathogenic species listeria innocua. coexpression of the positive regulatory factor prfa in the plasmid vector in conjunction with the structural gene hly increased the expression over 500-fold. purification from supernatant fluids was achieved by two steps of ion exchange chromatography. the procedure resulted in over 60% yield of a hemolytically active, homogeneous 58 kda protein which was u ...19958590646
modulation of the antilisterial activity of human blood-derived macrophages by activating and deactivating cytokines.a concept of macrophage deactivation by hormones and cytokines that opposes activation was recently proposed. deactivation of the antilisterial activity of macrophages by il-4, il-10, and tgf-beta, as well as by dexamethasone, was studied here. il-4, il-10, and dexamethasone, but not tgf-beta, caused a complete loss of the competence of human blood-derived macrophages infected with listeria monocytogenes to control or eliminate ingested bacteria. il-10 and, to a lesser degree, dexamethasone less ...19958590313
listeria monocytogenes infection in pregnant mice: abnormalities in the function of non-adherent accessory light density dendritic cells.pregnant a/j mice were found to be more susceptible to the lethal effect of listeria monocytogenes bacteria than virgin females. however, during the first four days of post-infection there was no difference in the elimination of listeria from the spleens of pregnant and virgin mice. this suggests that the increase in the susceptibility of pregnant mice to pathogenic activity of l. monocytogenes was related to the diminution in listeria-specific cellular reactions. indeed, we found that non-adher ...19958589664
listeriosis in bone marrow transplant recipients: incidence, clinical features, and treatment.cultures of blood and/or cerebrospinal fluid from four of 1,013 bone marrow transplant recipients treated at our center between january 1972 and april 1994 were positive for listeria monocytogenes. the overall occurrence of listeriosis was 0.39 case per 100 transplantations. allograft recipients had received prior treatment with parenteral methylprednisolone, thus supporting an association between listeriosis and corticosteroids. treatment with parenteral ampicillin (200 mg/[kg.d]) and gentamici ...19958589157
vector plasmid for insertional mutagenesis and directional cloning in listeria spp. 19958588903
a comparison between starch and polyacrylamide gels for the analysis of listeria monocytogenes using multilocus enzyme electrophoresis.forty-seven listeria monocytogenes isolates were analysed using multilocus enzyme electrophoresis in two laboratories. both assayed for the same six enzymes, but one used a starch gel method and the other polyacrylamide gels. the starch gel method distinguished six electrophoretic types whereas the polyacrylamide gel method produced 17 different electrophoretic types. the polyacrylamide gel method was more discriminatory than the starch gel method.19968588884
effects of benzylpenicillin on glucose utilization, macromolecule synthesis and cell wall proteins of listeria monocytogenes.when growing cells were incubated in the presence of 100 ppm benzylpenicillin (bp) for 30 min and then harvested for metabolic studies, the initial rate of glucose utilization by resting cells was reduced by 19.6% compared to control cells, whereas the rates of protein, dna and rna synthesis were reduced by 40.7%, 55.0% and 87.5% respectively. growth in the presence of 100 ppm bp for 2 h was found to result in a marked depletion of cell wall proteins.19968588883
effect of benzylpenicillin on the viability and osmotic sensitivity of listeria monocytogenes.growth in the presence of 100 ppm benzylpenicillin (bp) for 2 h failed to result in a detectable reduction in cfu. cells grown and incubated for 24 h in 0, 1, 10 and 100 ppm bp underwent reductions in cfu of 0%, 0%, 90% and 99% respectively of maximum cfu values.19968588882
rapid diagnosis of bacterial meningitis by a seminested pcr strategy.a polymerase chain reaction (pcr) based diagnostic assay has been developed for the simultaneous detection in cerebrospinal fluid (csf) of neisseria meningitidis, haemophilus influenzae, streptococcus pneumoniae, streptococcus agalactiae, listeria monocytogenes and bacteria in general. in the present communication we describe the design of primers for s. pneumoniae, s. agalactiae, and l. monocytogenes, and a general pcr protocol for the assay. the diagnostic outcome is presented for a small coll ...19958588152
[a new case of arterial listeria infection].listeria monocytogenes arterial infections are uncommon and usually occur on aneurysms of previously operated arteries, classically in very young and very old or immunodepressed subjects. peroperative samples for bacteriology should always be taken as antibiotics generally used in vascular surgery are ineffective against listeria. we report a case of a patient who underwent emergency surgery. bacteriologic analysis of the thrombus revealed listeria inoculation which was eradicated by adapted ant ...19958586958
frozen stored murine hybridoma cells can be used to determine the virulence of listeria monocytogenes.murine hybridoma cells, designated ped-2e9, when stored up to 60 days at -196 degrees c or up to 48 days at -80 degrees c, gave results equivalent to those for freshly grown murine hybridoma cells in an in vitro pathogenicity assay of listeria species. thus, laboratories do not need to have their own tissue culture facilities to maintain the hybridoma cells for the assay described.19958586737
the inla gene required for cell invasion is conserved and specific to listeria monocytogenes.the gram-positive bacterium listeria monocytogenes can actively induce its own uptake by epithelial cells and fibroblasts through a surface-exposed 80 kda protein, internalin (inia), encoded by inia. we studied the distribution and the dna polymorphism of inia sequences in a wide variety of wild strains of l. monocytogenes as compared to other listeria species. this was done by pcr-amplifying inia sequences encoding the fifteen repeats a and the three repeats b of inia. inia-repeated sequences w ...19968581163
typing of listeria monocytogenes by random amplified polymorphic dna (rapd) analysis.the aim of the study was to determine the effectiveness of random amplified polymorphic dna analysis in typing listeria monocytogenes from human infections. twenty-five l. monocytogenes serogroup 1/2 and 70 serogroup 4 including 14 serovar 4b(x) were typed by rapd-pcr analysis. six primers were used to type each l. monocytogenes isolate and the dna amplification performed with supertaq dna polymerase in a hybaid thermal reactor. each bacterial strain was analysed separately with all primers and ...19958579993
genomic subtraction in combination with pcr for enrichment of listeria monocytogenes-specific sequences.genomic dna from listeria innocua and listeria ivanovii was used in subtractive hybridization with dna from listeria monocytogenes involving two amplification strategies. subtraction was accomplished by labelling the subtracting dna with biotin and removal after liquid hybridization with tester dna (l. monocytogenes) by reaction with streptavidin and phenol extraction. in one strategy, l. monocytogenes dna was poly(a)-tailed with terminal transferase and amplified asymmetrically after subtractio ...19958579987
combined effect of gamma radiation and heating on the destruction of listeria monocytogenes and salmonella typhimurium in cook-chill roast beef and gravy.the effect of heating alone (60, 65 or 70 degrees c), heating after irradiation (0.8 kgy) and heating after irradiation and storage for 14 days at 2-3 degrees c on the destruction of listeria monocytogenes and salmonella typhimurium in artifically inoculated minced cook-chill roast beef and gravy was investigated. inoculated minced roast beef samples (5 g) were heated in stomacher bags completely immersed in a water bath at each of the test temperatures. survivors were enumerated and d and z val ...19958579983
the application of the wlf equation to predict lag time as a function of temperature for three psychrotrophic bacteria.many mathematical models for microbial growth rates or lag times have been proposed. most of these models either predict well, but are empirical and offer no insight into mechanism or they reflect mechanism but are too complex or do not fit the data adequately. the williams-landel-ferry (wlf) equation (used by polymer chemists) is empirical, but shows some relation to first principles, and hence may offer some insight into mechanism. this model also has only three parameters and therefore a fair ...19958579982
sequestration of inhaled particulate antigens by lung phagocytes. a mechanism for the effective inhibition of pulmonary cell-mediated immunity.dendritic cells (dcs) have emerged as the dominant antigen-presenting cells (apcs) of the lung, playing a vital role in the induction of cell-mediated immunity to inhaled antigens. we have previously demonstrated that an airway challenge with the soluble antigen hen egg lysozyme yields rapid acquisition of specific antigen-presenting cell activity by purified pulmonary dcs and a cell-mediated immune response in the lung upon secondary challenge. to examine how a particulate antigen leads to a ce ...19968579128
heterogeneous endolysins in listeria monocytogenes bacteriophages: a new class of enzymes and evidence for conserved holin genes within the siphoviral lysis cassettes.listeria monocytogenes bacteriophages a118, a500 and a511 are members of three distinct phage groups with characteristic host ranges. their endolysin (ply) genes were cloned and expressed in escherichia coli as demonstrated by the conferred lytic phenotype when colonies of recombinant cells were overlaid with a lawn of listeria cells. the nucleotide sequences of the cloned dna fragments were determined and the individual enzymes (ply118, 30.8 kda; ply500, 33.4 kda; ply511, 36.5 kda) were shown t ...19958577256
exposure of the lateral enterocyte membrane by dissociation of calcium-dependent junctional complex augments endocytosis of enteric bacteria.intestinal bacterial translocation is facilitated in a variety of clinical conditions involving increased intestinal permeability, such as shock and trauma. because there is both in vivo and in vitro evidence that enteric bacteria can be internalized by intestinal epithelial cells, experiments were designed to test the effect of increased intestinal permeability on enterocyte endocytosis of enteric bacteria. mature, confluent cultures of ht-29 enterocytes were placed in a calcium-free solution f ...19958574756
aerobic and anaerobic metabolism of listeria monocytogenes in defined glucose medium.a defined medium with glucose as the carbon source was used to quantitatively determine the metabolic end products produced by listeria monocytogenes under aerobic and anaerobic conditions. of 10 strains tested, all produced acetoin under aerobic conditions but not anaerobic conditions. percent carbon recoveries of end products, typified by strain f5069, were as follows: lactate, 28%; acetate, 23%; and acetoin, 26% for aerobic growth and lactate, 79%; acetate, 2%; formate, 5.4%; ethanol, 7.8%; a ...19968572709
transferable erythromycin resistance in listeria spp. isolated from food.an erythromycin-resistant (emr) listeria innocua and an emr listeria monocytogenes isolate both carried ermc genes, which code for rrna methylases. the ermc genes were transferable by conjugation to recipient l. monocytogenes, listeria ivanovii, and enterococcus faecalis but did not appear to be associated with conjugative plasmids.19968572704
ctl epitope generation is tightly linked to cellular proteolysis of a listeria monocytogenes antigen.listeria monocytogenes is a pathogenic intracellular bacterium that secretes proteins into the cytosol of host cells. a major secreted protein, p60, is processed by the host cell into the nonamer peptides p60 217-225 and p60 449-457, which are presented to ctl by h-2kd mhc class i molecules. herein, we use two membrane permeable peptide aldehyde protease inhibitors, llnl and z-llf, to inhibit cytosolic proteolysis in l. monocytogenes-infected cells. these inhibitors, which have been shown to inh ...19968568253
an iron-dependent mutant of listeria monocytogenes of attenuated virulence.a bank of tn917-insertional mutants from the facultative intracellular pathogen listeria monocytogenes was screened by an original method based on bacterial growth on synthetic medium under iron-limiting conditions. one mutant, whose in vitro growth in synthetic medium was specifically dependent upon the availability of iron in its environment, was isolated and characterized. the insertional event occurred in a non-coding region, upstream of a rrn operon and located within a 1100-kb noti fragmen ...19958566716
interleukin-4-producing cd4+ nk1.1+ tcr alpha/beta intermediate liver lymphocytes are down-regulated by listeria monocytogenes.experimental infection of mice with the intracellular bacterium, listeria monocytogenes, provides a paragon model for immune defence dominated by t helper type 1 (th1) responses. potent production of interleukin (il)-12 by infected macrophages is considered the determining factor in th1 cell development. in contrast, it is assumed that il-4 producers remain virtually unstimulated in listeriosis. in the liver, the major target organ of listeriosis, an unusual t lymphocyte population exists with t ...19958566018
the adjuvancy of silicones: dependency on compartmentalization.studies have been conducted in mice (b6c3f1) and rats (sprague dawley, fischer 344) to investigate the adjuvancy potential of silicone mammary gel and the low molecular weight silicone fluid, octamethylcyclotetrasiloxane (d4). dependent on the experimental conditions employed, a divergent data profile emerges. if the antigen (bovine serum albumin, bsa) is emulsified with either the gel or the d4 prior to intramuscular immunization, an amplified anti-bsa igg antibody response, as measured by mult ...19968565549
[spontaneous bacterial peritonitis caused by listeria monocytogenes].listeria monocytogenes is a gram-positive coccobacillus that produces infections in both the normal and the compromised host. symptomatic bacteremia and pulmonary infection or meningitis are the most common clinical presentations in adults. according to a current review of the literature, listeria is a rare bacteria that may produce spontaneous bacterial peritonitis (23 cases reported). listeria peritonitis occurs in more than two-thirds of the cases in patients with chronic liver disease, but m ...19958562197
intracerebral targets and immunomodulation of murine listeria monocytogenes meningoencephalitis.in humans, infection with listeria monocytogenes (l. monocytogenes) can severely affect the central nervous system (cns). in the present study we have employed a murine model of cns listeriosis to characterize the intracerebral distribution of l. monocytogenes. following intracerebral application of a low dose of l. monocytogenes (serovar 1/2a, egd strain) a severe fatal leptomeningitis, ventriculitis, and encephalitis developed. listeria were detectable both intracellularly in different cell ty ...19968558168
macrophages have cell surface il-10 that regulates macrophage bactericidal activity.il-10, which is secreted by multiple cell types, has regulatory effects on macrophages, including decreasing their ability to kill some microorganisms. the experiments presented here test the hypothesis that endogenous il-10 inhibits the ability of macrophages to kill the facultative intracellular bacterium, listeria monocytogenes. we show that the nonbactericidal macrophage hybrid, h36.12j (12j), can kill listeria after incubation for 3 days with anti-il-10 mab. il-10 was not detected in 12j ma ...19968557991
detection and characterization by differential pcr of host eukaryotic cell genes differentially transcribed following uptake of intracellular bacteria.host eukaryotic cell genes that are differentially transcribed after phagocytosis of various pathogenic and nonpathogenic bacterial cells were identified by a differential pcr (dpcr) system. this dpcr procedure favors detection and isolation of host genes affected at the transcriptional level by selecting for poly(a) tails but differs substantially from reverse transcription-pcr. several unidentified macrophage gene fragments from genes that were either transcriptionally activated or downregulat ...19968557379
occurrence of listeria species in ready to eat foods.over 8000 ready to eat foods were examined for the presence of listeria species. overall, 5% of foods were found to contain these organisms. higher occurrence was found in some foods such as chicken (11%) and fish (14%). most of the listeria species isolated were l. monocytogenes (49%) and l. innocua (36%) with lower numbers of other species. no seasonal pattern in the recovery of l. monocytogenes was found. unsatisfactory or potentially hazardous levels of l. monocytogenes were found in 14 prod ...19958557084
influence of steric stabilization of liposome-encapsulated hemoglobin on listeria monocytogenes host defense.liposome-encapsulated hemoglobin (leh) products are being investigated as potential blood substitutes. to determine if changes in leh composition can modify the immune response, red blood cell substitutes based on conventional lipids containing phosphatidylinositol (leh1) and sterically stabilized lipid vesicles containing polyethylene glycol phosphatidylethanolamine (leh2) were tested for effects on host resistance. on day 0, groups of 18 to 20 female cd-1 mice were given an intravenous (i.v.) ...19958556140
[wallenberg syndrome as a sign of rhombencephalitis-meningitis due to listeria monocytogenes].we report a case of rhombencephalitis with meningitis in a 36-years-old previously healthy man; neurological signs and symptoms were initially consistent with a diagnosis of wallenberg syndrome. analysis of cerebrospinal fluid showed predominantly lymphocytic pleocytosis and elevated protein levels. a ct brain scan was normal. mri of the brain showed a hypertensive type lesion in t2, in the right pontomedullary region that suggested inflammation. a blood culture grew listeria monocytogenes. the ...19958554785
vaccination of mice with attenuated mutants of listeria monocytogenes: requirement for induction of macrophage la expression.isogenic mutant strains of listeria monocytogenes demonstrating graded attenuation in mice were used to analyse the correlation between bacterial virulence, ability to induce class ii mhc (la) molecules in antigen presenting cells and ability to vaccinate against secondary infection. the mutants used differed only in the amino acid sequence of the thiol-activated hemolysin, listeriolysin o (llo). the results indicate that l. monocytogenes mutants of reduced virulence have the potential to act as ...19958551944
listeriolysin is a potent inducer of the phosphatidylinositol response and lipid mediator generation in human endothelial cells.the impact of listeria monocytogenes listeriolysin o (llo) secretion on phosphoinositide metabolism and mediator (platelet-activating factor and prostaglandin i2) generation was investigated in human umbilical vein endothelial cells. wild-type l. monocytogenes, purified llo, and an l. innocua strain engineered to secrete llo all elicited a strong response, whereas mutant strains defective in llo production were ineffective. thus, human umbilical vein endothelial cell stimulation by listeriae is ...19968550226
influence of beta 2-microglobulin expression on gamma interferon secretion and target cell lysis by intraepithelial lymphocytes during intestinal listeria monocytogenes infection.numerous microbial pathogens, including listeria monocytogenes, enter the host through the intestine. although relatively little is known about the biological functions of intestinal intraepithelial lymphocytes (i-iel), they are generally considered a first line of defense against intestinal infections. in the mouse, the vast majority of i-iel express the cd8 coreceptor either as a cd8 alpha/alpha homodimer or as a cd8 alpha/beta heterodimer. the cd8 receptor of t-cell receptor tcr gamma/delta i ...19968550209
[role of macrolides in the treatment of respiratory tract infections in children].macrolides are antibiotics with high intracellular concentrations. they have a bacteriostatic activity but are also bactericides for concentrations five times greater than the minimal inhibitory concentration, concentrations in which they reach in the respiratory tract. they are usually active on streptococcus, neisseria, moraxella catarrhalis, listeria monocytogenes, bordetella pertussis, pasteurella multocida, chlamydia, mycoplasma pneumoniae, legionella pneumophila and helicobacter pylori. th ...19958548000
two listeria monocytogenes ctl epitopes are processed from the same antigen with different efficiencies.listeria monocytogenes is an intracellular bacterium that elicits mhc class i-restricted ctl in infected mice. a major ctl specificity is the nonamer peptide p60 217-225, which is derived from the bacterial murein hydrolase p60 and presented by the h-2kd mhc class i molecule. in this report, we identify a second h-2kd presented peptide, encompassing residues 449-457 of p60, that is detected by l. monocytogenes-specific ctl. both p60-derived ctl epitopes are good competitors for h-2kd binding and ...19968543821
listeria monocytogenes induces apoptosis of infected hepatocytes.infection with blood-borne listeria monocytogenes results in their early uptake by the liver. foci of hepatocytes become heavily infected and develop into microabscesses. infection results in apoptosis of the hepatocytes. this is particularly evident in the edge of the microabscess, where hepatocytes are not yet destroyed by the neutrophil. it is also apparent when neutrophils are depleted from the circulation. infection of hepatocytes in culture induces their death by apoptosis with the release ...19968543820
il-15 is a novel growth factor for murine gamma delta t cells induced by salmonella infection.we have previously shown evidence for the early recruitment of gamma delta t cells during the disease course of primary infections with listeria monocytogenes or salmonella choleraesuis in mice. since gamma delta t cells at this stage of the disease do not produce il-2, the growth factor for the gamma delta t cells remains unknown. il-15 is a novel cytokine that uses beta- and gamma-chain of il-2r for signal transduction, and is produced by activated monocytes/macrophages. in this study, we inve ...19968543818
efficacy of meropenem in experimental meningitis.meropenem and comparator antibiotics, including ceftriaxone, ceftazidime, benzyl penicillin and a combination of ampicillin plus gentamicin, were evaluated in a model of bacterial meningitis in the guinea-pig. the model is an acute infection in which challenge with each organism, if untreated, causes an increase in numbers of white blood cells, elevation of protein concentrations and 6-8 log10 cfu/ml of bacteria in the csf. infections caused by haemophilus influenzae, neisseria meningitidis, thr ...19958543501
a monoclonal antibody against t-cell receptor alpha beta induces endogenous cytokines and prevents mice from a lethal infection with listeria monocytogenes.in vivo induction of cytokines by a monoclonal antibody (mab) against t-cell receptor (tcr) alpha beta and the protective effect induced by the mab on a lethal infection with listeria monocytogenes were studied. injection of anti-tcr alpha beta mab induced rapid production of endogenous tumour necrosis factor in the spleens, and gamma interferon and interleukin-6 in the blood streams and spleens of mice. administration of anti-cd4 mab, anti-cd8 mab, or anti-thy1.2 mab resulted in suppression of ...19958541810
[azithromycin, pharmacodynamic evaluation in animal models].several experimental models have been used in order to evaluate the in vivo efficacy of azithromycin against numerous human pathogenic bacteria and parasites, including comparison between azithromycin and other antibiotics belonging or not to the macrolide family. using the experimental models, three major objectives can be distinguished: the comparative studies of the efficacy dose 50 (ed50) of azithromycin compared to other orally given antibiotics, the azithromycin efficacy in animal infected ...19958539074
differentiation of epidemic-associated strains of listeria monocytogenes by restriction fragment length polymorphism in a gene region essential for growth at low temperatures (4 degrees c).the growth of listeria monocytogenes in food stored in the cold has often been implicated in outbreaks of listeriosis. many subtyping schemes have suggested that epidemic-associated strains belong to a unique genetic group. it has not yet been possible, however, to identify molecular or bacteriologic markers unique to epidemic-associated strains. recently we cloned three genes of l. monocytogenes, ltra, ltrb, and ltrc, which are essential for growth at low temperatures (4 degrees c). the use of ...19958534098
[nonspecific host defense mechanism by macrophages--analysis by nf-il6 deficient mice]. 19958532864
efficacy of a lactic acid/sodium benzoate wash solution in reducing bacterial contamination of raw chicken.raw chicken wings inoculated with salmonella, campylobacter jejuni, listeria monocytogenes, staphylococcus aureus, or escherichia coli o157:h7 were washed in water (control) or a solution of a 0.5% lactic acid/0.05% sodium benzoate (lb) (ph 2.64) for 30 min. viable cells of pathogenic bacteria and naturally occurring psychrotrophic bacteria on wings were enumerated after 0, 2, 4, 6, and 8 days of storage at 4 degrees c. lower populations of pathogenic and psychrotrophic bacteria were detected on ...19958527331
development of nasba, a nucleic acid amplification system, for identification of listeria monocytogenes and comparison to elisa and a modified fda method.nasba, an isothermal nucleic acid amplification system was used for identification of listeria monocytogenes. a primer set and a species-specific probe were selected from the 16s rrna sequence. the probe was shown to hybridize specifically to the amplified single-stranded rna of l. monocytogenes. no hybridization occurred with amplification product of l. seeligeri, l. innocua, l. ivanovii, and l. welshimeri. detection sensitivity for the nasba assay was determined at 10(6) cfu/ml. the possibilit ...19958527330
division of listeria monocytogenes serovar 4b strains into two groups by pcr and restriction enzyme analysis.altogether, 133 strains of listeria monocytogenes serovar 4b were investigated. a segment of 2,916 bp containing parts of the two genes inla and inlb in l. monocytogenes was amplified by the pcr technique. the pcr product obtained was cleaved with the restriction enzyme alui, and the fragments generated were separated by gel electrophoresis, leading to two distinct groups: pcr-restriction enzyme analysis groups i and ii, containing 37 and 96 strains, respectively. the pcr-restriction enzyme anal ...19958526498
cryptdins: endogenous antibiotic peptides of small intestinal paneth cells.we purified three peptides ("cryptdins") from the small intestines of mice, established their primary amino acid sequences and examined their antimicrobial activity. their primary sequences revealed approximately 50% identity to a group of antimicrobial defensins that we had previously isolated from the granules of rat neutrophils. in addition to their ability to kill gram-positive (l. monocytogenes) and gram-negative bacteria (e. coli and s. typhimurium) in vitro, the peptides were much more ac ...19958525919
[phosphatidylinositol specific phospholipase c (pi-plc) in differentiation of listeria monocytogenes and listeria innocua].listeria strains were investigated as regard: the production of pi-plc and lecytinase, haemolytic and camp activity survival in mouse tissues. although all the examined l. monocytogenes strains produced pi-plc, they showed a very different activity of this enzyme. it was surprising that one of the four l. innocua strains demonstrated a weak activity of pi-plc. l. monocytogenes bacteria with strong pi-plc activity survived in mouse spleens for a much longer period of time than l. monocytogenes mi ...19958523967
[acute hydrocephalus in listeria monocytogenes meningitis]. 19958523935
influences on the antimicrobial activity of surface-adsorbed nisin.the efficacy of the antimicrobial peptide nisin was examined after adsorption to silica surfaces. three protocols were used to evaluate nisin's activity against adhered cells of listeria monocytogenes: bioassay using pediococcus pentosaceous fbb 61-2 as the sensitive indicator strain; visualization and enumeration of cells by microscopic image analysis; and viability of adhered cells as determined by lodonitrotetrazolium violet uptake and crystallization. the activity of adsorbed nisin was highl ...19958519481
the contamination of paté by listeria monocytogenes in england and wales in 1989 and 1990.in july 1989, 1834 samples of paté (of which 1698 were from retail displays) were examined by the phls for the presence of listeria monocytogenes. the survey was repeated in july 1990, when 626 paté samples on retail sale were examined. between the two surveys there was a marked reduction in the proportions of patés contaminated (10% in 1989 and 4% in 1990) and in the numbers of samples from which > 10(3) l. monocytogenes/g were recovered. the higher rate of contamination detected in 1989 was la ...19938519319
a method for typing listeria monocytogenes strains by classification of listeriocins and phage receptors.a method for typing listeria monocytogenes (l.m.) strains was developed which is based on two different approaches. first, strains were classified according to the phage receptors specific to their mitomycin-induced prophages. the frequency of lysogenic strains ranged between 63 and 80%, depending on the serotype. for non-lysogenic strains, a reversed phage-receptor analysis was applied based on the susceptibility of the strains to be typed against bacteriophages from selected, inducible indicat ...19938518513
comparative activities of macrolide derivatives on murine listeriosis.the new macrolide derivatives such as clarithromycin, roxithromycin and azithromycin have only slightly stronger in vitro antibacterial activity on listeria monocytogenes than the older derivatives such as erythromycin and spiramycin. in vivo, however, the new macrolides exert a much better therapeutic action on murine listeriosis. among the new derivatives, clarithromycin is the most active. azithromycin has one characteristic advantage: it is still active several days after cessation of therap ...19938518506
detection of listeria monocytogenes in cheese with the magnetic immuno-polymerase chain reaction assay.a new detection system, the magnetic immuno-polymerase chain reaction (pcr) assay (mipa) has been developed to detect listeria monocytogenes in food. this method separates listeria cells from pcr-inhibitory factors present in enrichment broths containing food samples by using magnetic beads coated with specific monoclonal antibodies (mabs). the separated bacteria were lysed, and the supernatant containing the bacterial dna was subjected to the pcr. detection of l. monocytogenes in three naturall ...19938517730
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