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virulence factors of listeria monocytogenes. 19957786508
iacta of listeria ivanovii, although distantly related to listeria monocytogenes acta, restores actin tail formation in an l. monocytogenes acta mutant.a gene homologous to the acta gene of listeria monocytogenes was cloned from listeria ivanovii (strain clip257) by chromosome walking starting from the ilo gene that encodes the pore-forming toxin ivanolysin. the nucleotide sequence revealed that this gene, named iacta, encodes a protein of 1,044 amino acids (iacta) comprising a central region with seven highly conserved tandem proline-rich repeats of 47 amino acids. although iacta and acta share an overall similar structure, these two proteins ...19957790091
role of interleukin-6 in t-cell activation during primary and secondary infection with listeria monocytogenes.injection of recombinant interleukin-6 (il-6) into mice enhances recovery from infection with listeria monocytogenes. in this study, the role of il-6 during primary and secondary listeria infection was further tested. neutralization of il-6 by polyclonal antibody exacerbated primary infection and significantly delayed gamma interferon production by cultured spleen cells. in contrast, administration of anti-il-6 antibody at the time of secondary infection did not affect the recovery of mice from ...19957790102
neutrophils are essential for resolution of primary and secondary infection with listeria monocytogenes.the role for neutrophils in the resolution of primary and secondary infection with listeria monocytogenes was studied. the results show that although control mice started to clear listeria from their spleens and livers between days 2 and 4 of sublethal primary infection and eradicated bacteria in 2 weeks, mice given a specific granulocyte-depleting antibody (rb6-8c5) on days 4 or 6 of infection developed lethal listeriosis. likewise, treatment of immunized mice with rb6-8c5 monoclonal antibody a ...19957790763
listeria monocytogenes infection in a patient treated with methotrexate for rheumatoid arthritis.we describe a patient with rheumatoid arthritis who developed bacteremia from listeria monocytogenes after treatment with low dose oral pulse methotrexate. we discuss possible immunologic mechanisms for susceptibility to listeria infections. as the elderly population increases with more frequent use of immunosuppressive medications, clinical suspicion must be maintained to correctly diagnose and treat infections such as listeria.19957791185
listeriosis from consumption of raw-milk cheese. 19957791474
the role of defeathering in the contamination of turkey skin by salmonella species and listeria monocytogenes.this study was undertaken to determine whether the incidence of either salmonella spp. or listeria monocytogenes on turkeys at three commercial processors could be related to the type of defeathering system: 1) conventional, 58 c common bath scald; 2) kosher, 7 c common bath scald; or 3) steam-spray, 62 c nonimmersion scald. flocks were sampled before defeathering, after defeathering, and after chill at each facility. the incidence of salmonella-positive turkeys significantly increased subsequen ...19957792245
isolation and characterization of acidocin a and cloning of the bacteriocin gene from lactobacillus acidophilus.acidocin a, a bacteriocin produced by lactobacillus acidophilus tk9201, is active against closely related lactic acid bacteria and food-borne pathogens including listeria monocytogenes. the bacteriocin was purified to homogeneity by ammonium sulfate precipitation and sequential ion-exchange and reversed-phase chromatographies. the molecular mass was determined by high-performance liquid chromatography gel filtration to be 6,500 da. the sequence of the first 16 amino acids of the n terminus was d ...19957793908
suppression of listeria monocytogenes colonization following adsorption of nisin onto silica surfaces.nisin is an antimicrobial peptide proven to be an effective inhibitor of gram-positive bacteria. it is known that nisin can adsorb to various surfaces and still retain much of its original activity (m. a. daeschel, j. mcguire, and h. al-makhlafi, j. food prot. 55:731-735, 1992). in this study, nisin films were allowed to form on silanized silica surfaces and then exposed to medium containing listeria monocytogenes. representative areas were selected from each surface, and images of resident list ...19957793927
characterization of listeria monocytogenes isolated from poultry products and from the poultry-processing environment by random amplification of polymorphic dna and multilocus enzyme electrophoresis.a total of 289 listeria monocytogenes strains isolated from a poultry-processing environment and poultry products over a 6-month period were characterized by random amplification of polymorphic dna, (rapd) to pinpoint sources of contamination within the plant and gain some measure of the persistence of individual genotypes within this environment. eighteen rapd profiles (a through r) were identified within this group, with 64% (184 of 289) of all strains displaying a single rapd profile, rapd ty ...19957793936
investigations related to the epidemic strain involved in the french listeriosis outbreak in 1992.two hundred seventy-nine cases of human listeriosis (92 pregnancy-related cases and 187 non-pregnancy-related cases) caused by a serovar 4b and phagovar 2389:2425:3274:2671:47:108:340 strain were identified in france between march and december 1992. epidemiological investigations included a case-control study (not described here) and microbiological analyses of foods. results of the case-control study and characterization of food isolates identified pork tongue in jelly, a ready-to-eat meat prod ...19957793944
prosthetic hip-joint infection due to listeria monocytogenes. 19957795065
targeting of listeria monocytogenes acta protein to the plasma membrane as a tool to dissect both actin-based cell morphogenesis and acta function.actin assembly on the surface of listeria monocytogenes in the cytoplasm of infected cells provides a model to study actin-based motility and changes in cell shape. we have shown previously that the acta protein, exposed on the bacterial surface, is required for polarized nucleation of actin filaments. to investigate whether plasma membrane-associated acta can control the organization of microfilaments and cell shape, variants of acta, in which the bacterial membrane signal had been replaced by ...19957796802
incidence of antibiotic resistance in listeria species.to define the prevalence of antibiotic resistance in listeria species pathogenic for humans and animals, 1100 isolates (60 from cases of listeriosis and 1040 from food and environment) collected worldwide were screened. of the 61 tetracycline- and minocycline-resistant strains (37 listeria monocytogenes), 57 harbored tet(m); 4 non-l. monocytogenes isolates contained tet(s). one listeria innocua isolate was also resistant to streptomycin and contained the tet(m) and aad6 genes. an l. monocytogene ...19957797931
inhibition of listeria locomotion by mosquito oostatic factor, a natural oligoproline peptide uncoupler of profilin action.mosquito oostatic factor, a naturally occurring decapeptide (ydpapppppp), strikingly resembles the primary structure of oligoproline-rich regions within the protein acta, a bacterial surface protein required for listeria motility in host cells. when microinjected into listeria-infected ptk2 cells, the insect oostatic factor rapidly blocks listeria-induced actin rocket tail assembly as well as intracellular locomotion of this pathogen. at intracellular concentrations of about 90 nm, transient inh ...19957806356
listeria monocytogenes peritonitis. 19957821123
differential induction of macrophage-derived cytokines by live and dead intracellular bacteria in vitro.marked differences in the abilities of living and heat-killed brucella abortus and listeria monocytogenes organisms to induce production of tumor necrosis factor alpha by in vitro-cultured macrophages were observed. interleukin-1 and interleukin-6 appeared to be under different control. the results are discussed in relation to the induction of gamma interferon-producing th1 cells and acquired cellular resistance to infection by living vaccines but not killed vaccines.19957822049
a distinct array of proinflammatory cytokines is expressed in human colon epithelial cells in response to bacterial invasion.pathogenic bacteria that penetrate the intestinal epithelial barrier stimulate an inflammatory response in the adjacent intestinal mucosa. the present studies asked whether colon epithelial cells can provide signals that are important for the initiation and amplification of an acute mucosal inflammatory response. infection of monolayers of human colon epithelial cell lines (t84, ht29, caco-2) with invasive strains of bacteria (salmonella dublin, shigella dysenteriae, yersinia enterocolitica, lis ...19957814646
differential production of interferon-gamma and interleukin-4 in response to th1- and th2-stimulating pathogens by gamma delta t cells in vivo.exposure to various pathogens can stimulate at least two patterns of cytokine production by cd4-positive t cells. responses that result in secretion of interferon-gamma (ifn-gamma), lymphotoxin and interleukin-2 (il-2) are classified as t-helper-1 (th1); cd4+ t-cell production of il-4, il-5, il-9, il-10 and il-13 is called a t-helper-2 response (th2). differentiation of cd4+ t cells into either th1 or th2 cells is influenced by the cytokine milieu in which the initial antigen priming occurs. her ...19957816142
monoclonal antibodies specific for murine p55 and p75 tumor necrosis factor receptors: identification of a novel in vivo role for p75.monoclonal antibodies (mabs) specific for the murine p55 and p75 tumor necrosis factor (tnf) receptors were produced after immunization of armenian hamsters with the purified soluble extracellular domains of each receptor protein. four p55- (55r) and five p75 (tr75)-reactive mabs immunoprecipitated the appropriate receptor from the surface of l929 cells. none of the mabs cross-reacted with the other tnf receptor form. the mabs were functionally characterized by their ability to inhibit ligand bi ...19957836916
bactericidal properties of murine intestinal phospholipase a2.we purified a molecule from the murine small intestine that killed both escherichia coli and listeria monocytogenes, and identified it as intestinal phospholipase a2 (ipla2) by nh2-terminal sequencing and enzymatic measurements. the ability of ipla2 to kill. l. monocytogenes was greatly enhanced by 5 mm calcium, inhibited by egta and abolished after reduction and alkylation, suggesting that enzymatic activity was required for ipla2-mediated bactericidal activity. a mouse-avirulent phop mutant, s ...19957860744
targeted disruption of the p50 subunit of nf-kappa b leads to multifocal defects in immune responses.nf-kappa b, a heterodimeric transcription factor composed of p50 and p65 subunits, can be activated in many cell types and is thought to regulate a wide variety of genes involved in immune function and development. mice lacking the p50 subunit of nf-kappa b show no developmental abnormalities, but exhibit multifocal defects in immune responses involving b lymphocytes and nonspecific responses to infection. b cells do not proliferate in response to bacterial lipopolysaccharide and are defective i ...19957834752
unique order of the lymphocyte subset induction in the liver and intestine of mice during listeria monocytogenes infection.we investigated how nk cells, extrathymic t cells, and thymus-derived t cells are activated in mice during infection with an intracellular pathogen, listeria (l.) monocytogenes. although macrophages and granulocytes are known to be involved in the elimination of this pathogen in an early phase of infection, it was still controversial what type of lymphocytes are induced as effectors in subsequent phases. when mice were ip injected with 1 x 10(3) l. monocytogenes (a sublethal dose), a prominent i ...19957867076
hepatocytes can serve as accessory cells in the response of immune t lymphocytes to heat-killed listeria monocytogenes.previous findings in our laboratory indicated that the bulk of listeria monocytogenes injected intravenously into mice and recovered in the liver is taken up and replicates within hepatocytes. other investigators have shown that hepatocytes can display costimulatory adhesion molecules, express major histocompatibility complex class i and ii molecules, and secrete a number of cytokines, including interleukin-1 (il-1), il-6, and il-8. these data suggest that hepatocytes may serve as accessory cell ...19957868265
spontaneous bacterial peritonitis due to listeria monocytogenes. 19957872309
[spontaneous bacterial peritonitis due to listeria monocytogenes]. 19957877386
comparative study of the growth of listeria monocytogenes in defined media and demonstration of growth in continuous culture.a basic requirement for physiological studies with listeria monocytogenes is a chemically defined medium that supports growth of the bacterium in batch and continuous culture. a number of such media have been devised but comparative studies of their efficiency are few and none has been used in continuous culture. six of the media were compared for their ability to sustain sequential growth of l. monocytogenes in static and aerated batch culture with glucose as sole carbon source. the most suitab ...19957883647
bacteremia is required for invasion of the murine central nervous system by listeria monocytogenes.the ability of the facultative intracellular pathogen listeria monocytogenes to penetrate the central nervous system (cns) was studied by following the kinetics of brain invasion and histological lesions during an acute intravenous (i.v.) infection in the mouse. cns invasion occurred during the early phase of infection and produced severe meningoencephalitis characterized by multiple granulomatous foci predominantly located in the brainstem and associated with diffuse meningitis and an intense i ...19957476097
non-dystrophic 129 rej mice are susceptible to i.p. infection with listeria monocytogenes despite an ability to recruit inflammatory neutrophils to the peritoneal cavity.in this study we compared the host response to listeria monocytogenes in 129 rej mice with listeria-resistant (c57bl/6j) and susceptible (balb/c) mouse strains. in all experiments mice were inoculated by the i.p. route. 129 rej mice and balb/c mice were sensitive to listeriosis whilst c57bl/6j mice were relatively resistant to i.p. infection. relatively large numbers of viable bacteria could be detected in the spleens of 129 rej mice as early as 6 h following i.p. inoculation suggesting that dis ...19957476100
plant bacterial spores, active systemically as a separate entity, play a significant role in human illnesses such as cancer, granulomas, aids, and milky white abdominal ascites that currently defies recognition.there is currently an unrecognized chapter in medical illnesses, occurring in living human beings, that defies recognition in explaining the diseases' origin and growth, and failing accurately to account for the pathophysiology involved. it is pertinent, therefore, to alert medical science, based upon facts as uncovered by my research studies (1-5), that plant bacterial spores can exist as a separate entity systemically. being totally devoid of the presence of their adult origin, they can surviv ...19957476596
hydroxyquinoline overcomes pcr inhibition by uv-damaged mineral oil. 19957479051
the efficacy of a live listeria monocytogenes combined serotype 1/2a and serotype 4b vaccine.in each of two experiments, sheep and lambs were vaccinated by a subcutaneous injection of a test vaccine (consisting of a combined serotype 1/2a and serotype 4b live listeria monocytogenes culture) and challenged 16 days later with a mixture of the homologous wild strains. after challenge, the mortality rate of vaccinated sheep was 28.1% and that of controls 71.9%; that of lambs was 25.0%, although these had been inoculated with the ld70 dose. furthermore, in each of two field trials in listeri ...19957483765
studies of the detection of listeria monocytogenes by culture and pcr in cerebrospinal fluid samples from ruminants with listeric encephalitis.a total of 14 cerebrospinal fluid (csf) samples from ruminants clinically suspected of suffering from listeric encephalitis were examined by polymerase chain reaction (pcr) for the detection of listeria monocytogenes (l. m.). of these samples, 11 were examined bacteriologically. although the clinical diagnosis was confirmed in eight of 11 ruminants by histological and/or bacteriological examination of the brains, l. m. was only detected in one of the csf samples using pcr, and in none by culture ...19957483908
use of a fluorogenic probe in a pcr-based assay for the detection of listeria monocytogenes.a pcr-based assay for listeria monocytogenes that uses the hydrolysis of an internal fluorogenic probe to monitor the amplification of the target has been formatted. the fluorogenic 5' nuclease pcr assay takes advantage of the endogenous 5' --> 3' nuclease activity of taq dna polymerase to digest a probe which is labelled with two fluorescent dyes and hybridizes to the amplicon during pcr. when the probe is intact, the two fluorophores interact such that the emission of the reporter dye is quenc ...19957487008
a new method for direct detection of listeria monocytogenes from foods by pcr.the preparation of dna by alcohol precipitation in the presence of na1 was used to enable the direct detection of listeria monocytogenes in the amount of 10(3) cfu/0.5 g of sample. this procedure produces pcr-quality dna directly from foods, such as soft cheese and minced meat.19957487010
use of pulsed-field gel electrophoresis to link sporadic cases of invasive listeriosis with recalled chocolate milk.pulsed-field gel electrophoresis established the linkage between recalled chocolate milk and a multistate invasive listeriosis outbreak during a four-product recall period. listeria monocytogenes isolates from four hospitalized patients and an environmental dairy sample displayed asci restriction endonuclease digestion profiles identical to that of the chocolate milk isolate.19957487050
the induction of renal autoantigen-specific t cells by a local listeria monocytogenes infection.in order to examine the possibility that a local chronic infection can induce organ-specific autoimmune disease, we inoculated unilateral kidneys with viable listeria monocytogenes (intrarenal infection). the delayed footpad reaction against syngeneic kidney homogenate (kh) became positive from 1 week after initiating the intrarenal infection. a proliferative response of the spleen t cells from the infected mice was also observed against kh from 1 week after initiating the intrarenal infection, ...19957490117
a protective role of gamma delta t cells in primary infection with listeria monocytogenes in autoimmune non-obese diabetic mice.we investigated the host defense mechanism in primary infection with listeria monocytogenes in non-obese diabetic (nod) mice at pre-diabetic stage showing an impaired responsiveness of the alpha beta t cells to t-cell receptor (tcr) triggering. the nod mice showed a deteriorated resistance at the late stage after an intraperitoneal infection with l. monocytogenes compared with balb/c and c57bl/6 mice as assessed by bacterial growth in organs. consistent with our previous findings, a prominent in ...19957490118
tumour necrosis factor, but not interferon-gamma, is essential for acquired resistance to listeria monocytogenes during a secondary infection in mice.mice with a secondary listeria monocytogenes infection eliminate the bacteria much faster and more efficiently from their organs than mice with a primary infection. during the course of a secondary infection, serum concentrations of interferon-gamma (ifn-gamma) and tumour necrosis factor-alpha (tnf) are higher than during a primary infection. the aim of the present study was to determine whether these cytokines are involved in the acquired resistance to l. monocytogenes during a secondary infect ...19957490127
purification of a 92 kda human immunostimulating glycoprotein obtained from the tamm-horsfall glycoprotein.a purification method for a human urinary glycoprotein (hgp92) dissociated from tamm horsfall protein (thp) is described. tamm-horsfall protein, obtained by salt precipitations, was again precipitated in presence of monovalent ions. in these conditions, tamm-horsfall protein displayed a tendency to form a gel. after ultracentrifugation, hgp92, which was trapped in the gel, was dissociated from tamm-horsfall protein and found in the supernatant. the final step of purification of hgp92 was chromat ...19957490460
listeria monocytogenes exists in at least three evolutionary lines: evidence from flagellin, invasive associated protein and listeriolysin o genes.regions of the genes encoding flagellin (flaa), the invasive associated protein (iap), listeriolysin o (hly) and 23s rrna were sequenced for a range of listeria monocytogenes isolates of different origin and serotypes. several nucleotide sequence variations were found in the flaa, iap and hly genes. no differences were found for the rrna genes, but our approach does not exclude the existence of differences between single copies of these genes. based on the sequence differences, the l. monocytoge ...19957496516
hot water extracts of chlorella vulgaris reduce opportunistic infection with listeria monocytogenes in c57bl/6 mice infected with lp-bm5 murine leukemia viruses.the bacterial elimination after infection with listeria monocytogenes was impaired in mice with murine acquired immunodeficiency syndrome (maids) by infection with lp-bm5 murine leukemia virus. oral administration of hot water extracts of chlorella vulgaris (cve) restored the capacity of maids mice to eliminate l. monocytogenes in association with improvement of the deteriorated immune response to l. monocytogenes. dth response to listeria in cve-treated maids mice was significantly higher than ...19957499027
identification of a cd4+ t cell-stimulating antigen of pathogenic bacteria by expression cloning.identifying the immunogenic proteins that elicit pathogen-specific t cell responses is key to rational vaccine design. while several approaches have succeeded in identifying major histocompatibility complex (mhc) class i bound peptides that stimulate cd8+ t cells, these approaches have been difficult to extend to peptides presented by mhc class ii molecules that stimulate cd4+ t cells. we describe here a novel strategy for identifying cd4+ t cell-stimulating antigen genes. using listeria monocyt ...19957500019
a new procedure for efficient recovery of dna, rna, and proteins from listeria cells by rapid lysis with a recombinant bacteriophage endolysin.a method for the rapid lysis of listeria cells, employing a recombinant listeria bacteriophage a118 lytic enzyme (ply118), is described. the procedure can be used with all listerial species. it enables fast, efficient, and gentle recovery of dna, rna, or native cellular proteins from small-scale (2- to 5-ml) cultures. moreover, this approach should be very useful in analytical detection and differentiation of listeria strains when the release of native nucleic acids or proteins is required.19957540820
evaluation of laboratory tests for confirming the diagnosis of encephalitic listeriosis in ruminants.retrospective analysis of 93 bovine, ovine, and caprine cases diagnosed as listerial encephalitis revealed positive bacterial isolations in only 63% of 59 cases in which bacterial culture was attempted. only 42% of 41 attempted bovine brain cultures were successful, compared with 67% from 6 sheep brains and 92% from 12 goat brains. gram stains and listeria-specific immunohistochemistry were evaluated as tools for verifying the presence of bacteria or listerial antigens in 38 animals. sixteen of ...19957542480
restricted replication of listeria monocytogenes in a gamma interferon-activated murine hepatocyte line.the intracellular pathogen listeria monocytogenes replicates mainly in resting macrophages and hepatocytes residing in infected tissues. both innate and acquired resistance strongly depend on activation of listericidal capacities of macrophages by gamma interferon (ifn-gamma) produced by natural killer cells and t lymphocytes. in contrast to macrophages, hepatocytes have been considered to serve purely as a cellular habitat, prolonging survival of the pathogen in the host. by using an immortaliz ...19957542640
[effectiveness of modified atmospheres against psychrotrophic pathogenic microorganisms in proteinaceous food].modified atmosphere packaging (map) of proteinaceous raw foods (meat, poultry and fish) extends their shelf-lives. it is well established that modified atmospheres (ma) inhibit the psychotropic aerobic gram-negative bacteria, the main spoilage microflora of proteinaceous raw foods stored under refrigeration. several researchers have warned about the possible growth of food poisoning microorganisms on them. considering the minimal growth temperatures of pathogens, this review only deals with aero ...19957546447
listeria monocytogenes: a live vector able to deliver heterologous protein within the cytosol and to drive a cd8 dependent t cell response.after an introduction on the entry and lifestyle of listeria monocytogenes within mammalian eucaryotic cells, this chapter gives a brief overview of murine experimental listeriosis. among the main characteristics of this murine model of infectious/pathogenic processes initiated by a facultative intracellular bacteria, we point out two main recent advances. one relates to listeria monocytogenes-induced production of cytokines as local, and transient signals able to direct the immune responses alo ...19957546656
lactic acid inhibition of the growth of spoilage bacteria and cold tolerant pathogens on pork.the antibacterial effects of a 3% solution of lactic acid at 55 degrees c were assessed, by examining aerobic bacterial growth on artificially-inoculated pork fat and lean tissue. discs of fat or lean tissues, each of 10 cm2 surface area, were aseptically excised from pork longissimus dorsi muscle and inoculated with the cold tolerant pathogens listeria monocytogenes 4b scott a no. 3, yersinia enterocolitica 0:4,32 or aeromonas hydrophila atcc 7966, or with the wild type spoilage bacteria pseudo ...19957547145
a method and medium for the electrical detection of listeria spp. from food.the development of a liquid medium for the detection of listeria spp. by capacitance monitoring of food samples previously enriched in uvm 1 broth is described. rapid growth of listeria monocytogenes was shown to occur in liquid media with selectivity based on antibiotics found in oxford agar. the final capacitance medium contained higher concentrations of the oxford selective agents than oxford agar and did not require the esculin/ferric ammonium citrate reaction to be observed. the medium reli ...19957547148
antilisterial activity of thermophilin 347, a bacteriocin produced by streptococcus thermophilus.streptococcus thermophilus 347 isolated from yogurt produces a bacteriocin referred as thermophilin 347. the bacteriocin was evidenced in the neutralized, filtered and catalase treated culture supernatant fluid of the producer strain. after partial purification, thermophilin 347 exhibited a bactericidal effect against listeria monocytogenes and several closely related lactic acid bacteria. the activity of thermophilin 347 was lost after protease treatment but was maintained after heating at 100 ...19957547149
attenuated listeria monocytogenes as a live vector for induction of cd8+ t cells in vivo: a study with the nucleoprotein of the lymphocytic choriomeningitis virus.listeria monocytogenes spends most of its intracellular life cycle in the cytosol of the infected eucaryotic cells. within this cellular compartment originates the endogenous pathway of antigen processing and presentation. we thus assumed that recombinant l. monocytogenes expressing an heterologous protein, the nucleoprotein of the lymphocytic choriomeningitis virus (lcmv), should be able to induce antigen-specific cd8+ t cells in vivo. the lcmv nucleoprotein gene was inserted in phase with the ...19957547706
joint infections due to listeria monocytogenes: case report and review.joint infections of bone are unusual manifestations of listerial infection. fourteen cases of septic arthritis due to listeria monocytogenes have been previously described in adults. we report the 15th case of septic arthritis due to listeria in which bilateral prosthetic hips in a renal transplant patient were involved. in addition, we review the literature on listerial joint infections.19957548508
polymerase chain reaction for the detection of listeria species and listeria monocytogenes. 19957550712
genetic analysis of acidocin b, a novel bacteriocin produced by lactobacillus acidophilus.the genes encoding the production of acidocin b, a bacteriocin produced by lactobacillus acidophilus strain m46 which is active against listeria monocytogenes, clostridium sporogenes, brochothrix thermosphacta, lactobacillus fermentum and lactobacillus delbrueckii subsp. bulgaricus, but inactive against most other lactobacillus species, were previously localized on a 4 kb xbai-hindiii fragment of plasmid pcv461. in the present work, dna sequence analysis revealed the presence of three consecutiv ...19957551031
mesentericin y105 gene clusters in leuconostoc mesenteroides y105.because of their potential usefulness as natural food preservatives, increased interest has focused on bacteriocins from lactic acid bacteria. mesentericin y105 is a small non-lantibiotic bacteriocin (class ii) encoded within a 35 kb plasmid from leuconostoc mesenteroides y105 and it is active against listeria monocytogenes. using reverse genetic methodologies, an 8 kb draii fragment has been cloned that contains the mesentericin y105 structural gene, mesy, which encodes a precursor of the bacte ...19957551032
reduction of exogenous ferric iron by a surface-associated ferric reductase of listeria spp.the reduction of exogenous ferric iron by listeria monocytogenes, a gram-positive food-borne pathogen, was investigated. using an assay incorporating the ferrous iron chelator ferrozine, we showed that intact cells of l. monocytogenes, when exposed to ferric iron, were able to rapidly reduce and solubilize the iron to the ferrous form. reduction occurred only after direct contact between the bacteria and the iron source. a number of different ferric iron chelates, including transferrin and lacto ...19957551061
interferon-gamma detection in cultures of newborn cells exposed to listeria monocytogenes.clearance of listeria monocytogenes in experimental models of infection has underscored the importance of interferon-gamma (ifn-gamma) in host resistance to intracellular pathogens. because l. monocytogenes infections are more severe in newborns than adults, we compared ifn-gamma accumulation in the supernatants of mononuclear cells infected in vitro from newborns with those from adults. supernatants were assayed for ifn-gamma using an enzyme-linked immunosorbent assay. uninfected newborn and ad ...19957553234
granzyme a-deficient mice retain potent cell-mediated cytotoxicity.granzyme a, a granule-associated serine proteinase of activated cytotoxic t cells and natural killer cells, has been reported to play a critical role in dna fragmentation of target cells. to address the question of the biological role of granzyme a, we have now generated a granzyme a-deficient mouse mutant by homologous recombination. western blot analysis, enzyme assays and reverse transcription-pcr confirmed the absence of granzyme a in activated t cells. in addition, deletion of granzyme a do ...19957556064
characterization of superoxide dismutase genes from gram-positive bacteria by polymerase chain reaction using degenerate primers.an internal fragment representing approximately 85% of sod genes from seven gram-positive bacteria was amplified by using degenerate primers in a polymerase chain reaction assay. the dna sequences of sod polymerase chain reaction products from clostridium perfringens, enterococcus faecalis, enterococcus faecium, lactococcus lactis, staphylococcus aureus, streptococcus agalactiae, streptococcus pneumoniae, and streptococcus pyogenes were determined. comparisons of their deduced amino acid sequenc ...19957557308
utilization of the leucocin a export system in leuconostoc gelidum for production of a lactobacillus bacteriocin.the lactacin f complex, composed of lafa and lafx peptides, is produced by lactobacillus johnsonii vpi 11088 (atcc 11506) and is active against various lactobacilli and enterococcus faecalis. the genetic determinants encoding the lactacin f peptides, lafa and lafx, are organized in a chromosomal operon comprised of genes lafa, lafx, and orfz. the lactacin f operon was introduced into leuconostoc (lc.) gelidum ual187-22 which produces leucocin a. leucocin a, a plasmid-encoded bacteriocin, inhibit ...19957557315
interaction of interleukin-6, tumour necrosis factor and interleukin-1 during listeria infection.injected recombinant interleukin-6 (il-6), tumour necrosis factor (tnf) and il-1 all protect mice against experimental infection with listeria monocytogenes. we have therefore investigated the interaction of these cytokines during infection. treatment with recombinant (r)il-6 enhanced tnf production by spleen cells during the first 2 days of infection. anti-tnf antibody could totally abolish the protective effect of ril-6, while the optimal protective function of tnf could not be achieved when i ...19957558150
expression of the listeria monocytogenes egd inla and inlb genes, whose products mediate bacterial entry into tissue culture cell lines, by prfa-dependent and -independent mechanisms.internalization of listeria monocytogenes into nonphagocytic cell lines in vitro requires the products of the inlab locus (j.-l. gaillard, p. berche, c. frehel, e. gouin, and p. cossart, cell 65:1127-1141, 1991). by generating isogenic mutants with a chromosomal in-frame deletion in either inla or inlb, we have identified inla and inlb as surface-bound proteins of l. monocytogenes with molecular weights of 88,000 and 65,000, respectively. these results were obtained with monoclonal antibodies ra ...19957558297
salmonella strain secreting active listeriolysin changes its intracellular localization.we describe the construction of an attenuated salmonella dublin aroa strain which secretes via the escherichia coli hemolysin secretion machinery an active hybrid cytolysin consisting of listeriolysin from listeria monocytogenes and the c-terminal secretion signal of e. coli hemolysin. this hemolytic s. dublin strain is partially released into the cytoplasm of the host cell following uptake by j774 macrophage cells, whereas the nonhemolytic control s. dublin aroa strain remains in the phagosome.19957558345
myosin is involved in postmitotic cell spreading.we have investigated a role for myosin in postmitotic potoroo tridactylis kidney (ptk2) cell spreading by inhibitor studies, time-lapse video microscopy, and immunofluorescence. we have also determined the spatial organization and polarity of actin filaments in postmitotic spreading cells. we show that butanedione monoxime (bdm), a known inhibitor of muscle myosin ii, inhibits nonmuscle myosin ii and myosin v adenosine triphosphatases. bdm reversibly inhibits ptk2 postmitotic cell spreading. lis ...19957559774
secondary response to listeria infection requires ifn-gamma but is partially independent of il-12.during a secondary immune response to listeria monocytogenes (lm), the production of ifn-gamma was still required for resistance, but it was considerably less dependent on il-12 production. when il-12 was neutralized in vivo using specific hamster antimurine il-12 mabs, there was a dramatically increased susceptibility to infection during primary listeriosis but much less during a secondary infection. however, neutralization of ifn-gamma in vivo resulted in a similar increased susceptibility dur ...19957561037
erythromycin is ineffective against listeria monocytogenes in multidrug resistant cells.multidrug resistance of tumor cells is a well-known phenomenon in oncology. among the substances excluded from the cells are not only antineoplastic drugs but also certain antibiotics, e.g. erythromycin. to prove the hypothesis that this might render infections with intracellular bacteria untreatable with these antibiotics we used erythromycin to treat intracellular infection of multidrug resistant (mdr) cells with listeria monocytogenes. erythromycin was unable to restrict the growth of l. mono ...19957562011
entry of listeria monocytogenes into hepatocytes requires expression of inib, a surface protein of the internalin multigene family.the intracellular bacterium listeria monocytogenes can invade several types of normally non-phagocytic cells. entry into cultured epithelial cells requires the expression of inia, the first gene of an operon, comprising two genes: inia, which encodes internalin, an 800-amino-acid protein, and inib, which encodes a 630-amino-acid protein. several genes homologous to inia are detected in the genome of l. monocytogenes; inib is one of them. we have assessed the role of inib in invasiveness of l. mo ...19957565087
correlation between the presence of virulence-associated genes as determined by pcr and actual virulence to mice in various strains of listeria spp.five chromosomal genes, prfa, plca, hlya, mpl and plcb, are implicated in the virulence of listeria monocytogenes and some of these genes have been used for the identification of bacteria by polymerase chain reaction (pcr). using 6 strains of l. monocytogenes and 3 l. innocua strains, the relationship was examined between the presence of five virulence-associated genes and actual virulence to mice in terms of 50% lethal dose (ld50), bacterial viability in the organ of infected mice and the intra ...19957565175
the sulphydryl-activated cytolysin and a sphingomyelinase c are the major membrane-damaging factors involved in cooperative (camp-like) haemolysis of listeria spp.the negative mutant approach was used in this study to identify listerial cytolytic factors involved in cooperative haemolysis (camp-like phenomenon) with staphylococcus aureus and rhodococcus equi. a listeria monocytogenes non-haemolytic mutant specifically impaired in listeriolysin o (llo) production gave no camp reaction with s. aureus, and was virtually camp-negative with r. equi, indicating that the listerial sulphydryl-activated toxin played a major role in cooperative haemolysis. this was ...19957569324
direct detection of listeria monocytogenes in 25 milliliters of raw milk by a two-step pcr with nested primers.a method for direct detection of listeria monocytogenes in 25 ml of raw milk is presented. the detection limit can be situated between 10 and 5 cfu. the detection method is based on chemical extraction of the milk components and pcr amplification with two nested pairs of primers specific for listeria monocytogenes.19957574620
efficacy of ozonated water against various food-related microorganisms.the antimicrobial effects of ozonated water in a recirculating concurrent reactor were evaluated against four gram-positive and four gram-negative bacteria, two yeasts, and spores of aspergillus niger. more than 5 log units each of salmonella typhimurium and escherichia coli cells were killed instantaneously in ozonated water with or without addition of 20 ppm of soluble starch (ss). in ozonated water, death rates among the gram-negative bacteria--s. typhimurium, e. coli, pseudomonas aeruginosa, ...19957574656
microbiology of fresh and restructured lamb meat: a review.microbiology of meats has been a subject of great concern in food science and public health in recent years. although many articles have been devoted to the microbiology of beef, pork, and poultry meats, much less has been written about microbiology of lamb meat and even less on restructured lamb meat. this article presents data on microbiology and shelf-life of fresh lamb meat; restructured meat products, restructured lamb meat products, bacteriology of restructured meat products, and important ...19957576150
enrichment in fraser broth supplemented with catalase or oxyrase, combined with the microcolony immunoblot technique, for detecting heat-injured listeria monocytogenes in foods.the microcolony immunoblot technique using monoclonal antibodies to listeria monocytogenes was evaluated for its suitability to detect heat-injured cells. pasteurized milk and filtrates of homogenized raw ground beef slurry and cabbage were inoculated with l. monocytogenes scott a, heated, diluted, inoculated into fraser broth (fb) supplemented with 400 micrograms of catalase ml-1 or 0.01 unit of oxyrase ml-1, and incubated at 30 degrees c for 6 h. three inoculum populations (high, medium, and l ...19957577355
factors affecting results obtained with european community tests for pasteurized milk sampled at the heat treatment establishment.a total of 3000 samples of pasteurized milk taken at the heat treatment establishment over a 1-year period were examined for the presence of phosphatase and by a plate count at 30 degrees c, a coliform count at 30 degrees c, and a plate count at 21 degrees c after pre-incubation of the sample for 5 days at 6 degrees c, performed as prescribed in ec directive 85/397/eec. samples were also examined for presence of listeria species. of 2690 samples (1713 from small dairies and 977 from large commer ...19957577356
occurrence of listeria monocytogenes in soft and semi-soft cheeses in retail outlets in sweden.samples of 333 retail cheeses produced in or imported into sweden were examined for the presence of listeria monocytogenes. listeria monocytogenes was isolated from 6% of the cheese samples. cheeses made from raw milk were more frequently contaminated with l. monocytogenes (42%) than cheeses made from heat-treated milk (2%). the incidence of the organism in whole cheeses and pre-cut wedges was similar (6%). l. monocytogenes was only found in imported cheeses (18 from france, and one from germany ...19957577361
cleaning and disinfection practice in the meat industries of europe.the application and efficacy of cleaning and disinfection methods are reviewed, together with the relevant european and french legislation. european commission hygiene directive 93/43/eec of 14 june 1993 proposes the adoption of hazard analysis and critical control points (haccp) for the meat industry, and this includes cleaning and disinfection. it is necessary to organise a team for washing, cleaning, rinsing, disinfection and final rinsing; three different types of organisation are compared. ...19957579634
influence of staphylococcal enterotoxin b (seb) on the course of murine listeriosis.confrontation of the immune system with bacterial superantigens leads to an initial activation of the immune system followed by a state of profound immunosuppression. to investigate the role of a superantigen in an acute infection with a facultatively intracellular bacterium, we have studied the effect of staphylococcal enterotoxin b on the course of murine listeriosis. intraperitoneal injection of seb led to a statistically significant growth restriction of listeria monocytogenes in the organs ...19957581273
development and characterization of monoclonal antibodies specific for the genus listeria.monoclonal antibodies were obtained by the classic hybridoma technique with lymphocytes of balb/c mice immunized with formalin killed listeria monocytogenes cells. among 1000 hybridomas issued from the fusion, four monoclonal antibodies (mabs a6 a e4, c10 a f7, g4 a d6, g7 a d5) gave interesting results. by western-blot analysis with various soluble extracts of different listeria species, the four mabs reacted with two major antigens of 38 and 41 kda, with all listeria species tested. the mab a6 ...19957581274
the bacterial actin nucleator protein acta of listeria monocytogenes contains multiple binding sites for host microfilament proteins.several intracellular pathogens, including listeria monocytogenes, use components of the host actin-based cytoskeleton for intracellular movement and for cell-to-cell spread. these bacterial systems provide relatively simple model systems with which to study actin-based motility. genetic analysis of l. monocytogenes led to the identification of the 90 kd surface-bound acta polypeptide as the sole bacterial factor required for the initiation of recruitment of host actin filaments. numerous host a ...19957583101
a recombinant listeria monocytogenes vaccine expressing a model tumour antigen protects mice against lethal tumour cell challenge and causes regression of established tumours.listeria monocytogenes is an intracellular organism that has the unusual ability to live in the cytoplasm of the cell. it is thus a good vector for targeting protein antigens to the cellular arm of the immune response. here we use a model system, consisting of colon and renal carcinomas that express the influenza virus nucleoprotein and a recombinant l. monocytogenes that secrets this antigen, to test the potential of this organism as a cancer immunotherapeutic agent. we show that this recombina ...19957585097
characterization of diacetin b, a bacteriocin from lactococcus lactis subsp. lactis bv. diacetylactis ul720.fourteen lactococcus lactis strains showing inhibitory activity against listeria innocua sicc 4202 were isolated from different french raw milks and raw milk cheeses and screened for bacteriocin production by the triple layer method under conditions that eliminate the effects of lactic acid and hydrogen peroxide. three bacteriocinogenic strains (two lactococcus lactis subsp. lactis bv. diacetylactis ul719 and ul720 and one lactococcus lactis subsp. lactis ul730) were selected for their high capa ...19957585360
regression of established tumors in mice mediated by the oral administration of a recombinant listeria monocytogenes vaccine.we have shown previously that listeria monocytogenes, a gram-positive, facultative intracellular bacterium, is a potent vector for targeting tumor-specific antigens to the immune system. after parenteral administration, we observed protection against both renal and colorectal mouse tumors and regression of established renal tumors. in the present study, we have exploited the fact that the normal route of infection of this organism is through the gut. we show that an l. monocytogenes recombinant ...19957585503
cefotaxime for treatment of neonatal sepsis and meningitis.neonatal sepsis is a clinical syndrome characterized by systemic signs and symptoms, and bacteremia during the first month of life. the incidence is relatively low (one to eight cases/1000 live births), yet the risk of mortality is approximately 25%. meningitis in the neonate is usually a sequela of bacteremia; however, it is discussed with neonatal sepsis, because they commonly share etiology and pathogenesis. the incidence of meningitis is usually a fraction of the number of infants with sepsi ...19957587023
antimicrobial activity of cefotaxime tested against infrequently isolated pathogenic species (unusual pathogens).the cefotaxime sodium spectrum of activity is very broad and includes many common species and a variety of less frequently isolated pathogens. we have reviewed the clinical microbiology literature (44 references) and the data base of the university of iowa hospitals and clinics (iowa city, ia) to collect data on the activity of cefotaxime against the less common species. cefotaxime was consistently active against actinobacillus actinomycetemcomitans, capnocytophaga spp., eikenella corrodens, ery ...19957587049
listeriolysin generates a route for the presentation of exogenous antigens by major histocompatibility complex class i.we have exploited the pore forming activity of listeriolysin, the hemolysin of listeria monocytogenes, to activate cd8+ t cells with soluble proteins in vivo and in vitro. immunization with soluble, hemolytically active listeriolysin induces both cytotoxic cd8+ t cells and cd4+ t cells, and the cd8+ t cells can be propagated with soluble listeriolysin in vitro. moreover, conventional antigens like ovalbumin mixed together with listeriolysin are also efficiently introduced into the mhc class i pa ...19957589099
the actin-polymerization protein from listeria ivanovii is a large repeat protein which shows only limited amino acid sequence homology to acta from listeria monocytogenes. 19957590161
combined autoimmune cytopenias.autoimmune neutropenia (ain) can occur in association with autoimmune hemolytic anemia (aiha) and/or immune thrombocytopenic purpura (itp), although these associations have not been studied in detail.19957590498
prevention of mortality by in vivo depletion of alpha beta t cells in murine lethal listeriosis and involvement of gamma delta t cells in bacterial elimination.we previously demonstrated that in murine lethal listeriosis, death is mainly due to massive liver necrosis. in the present study we found that in vivo depletion of alpha beta t cells by administration of anti-tcr beta mab (h57-597) protected recipient mice from acute mortality and converted lethal listeriosis to sublethal infection. furthermore, our findings suggested that gamma delta t cells were not involved in the liver necrosis in this condition. after depletion of alpha beta t cells, the n ...19957590864
listeria monocytogenes infection increases neutrophil adhesion and damage to a murine hepatocyte cell line in vitro.several studies have reported that listeria monocytogenes multiples within hepatocytes and that inflammatory neutrophils inhibit this intracellular growth in vivo. in the present study, we used a murine embryonic hepatocyte cell line (atcc tib73) as an in vitro model to investigate neutrophil-hepatocyte interactions. murine peritoneal exudate neutrophils adhered more readily to l. monocytogenes-infected hepatocyte monolayers than to uninfected monolayers or monolayers infected with acta- and hly ...19957590905
the two distinct phospholipases c of listeria monocytogenes have overlapping roles in escape from a vacuole and cell-to-cell spread.listeria monocytogenes secretes two distinct phospholipases c, a phosphatidylinositol-specific phospholipase c (pi-plc) and a broad-range phospholipase c (pc-plc). in this study, single in-frame deletion mutants with mutations in each plc and a double mutant lacking both plcs were characterized with regard to virulence in mice, escape from a primary vacuole, and cell-to-cell spread in cell culture. the mutant lacking pi-plc, previously shown to be twofold less virulent than the wild type in mice ...19957591052
listeria monocytogenes infects human endothelial cells by two distinct mechanisms.infection of endothelial cells by bacteria may be an important component of the bacteria's ability to escape host defenses and cause disease. listeria monocytogenes cause sepsis and central nervous system infection in domesticated animals and immunocompromised humans, suggesting that this bacterium interacts with endothelial cells in a significant fashion. the experiments presented here tested the hypothesis that l. monocytogenes can invade and replicate within human endothelial cells. we found ...19957591057
a species-specific nucleotide sequence of mycobacterium tuberculosis encodes a protein that exhibits hemolytic activity when expressed in escherichia coli.species-specific proteins may be implicated in the unique pathogenic mechanisms characteristic of mycobacterium tuberculosis. in previous studies, a 3.0-kb species-specific dna fragment of m. tuberculosis was identified (c. a. parra, l. p. londoño, p. del portillo, and m. e. patarroyo, immun. 59:3411-3417, 1991). the nucleotide sequence of this 3.0-kb fragment has been obtained. this sequence was shown to contain two open reading frames (orfs) whose putative gene products share 68.9% identity be ...19957591062
the broad-range phospholipase c and a metalloprotease mediate listeriolysin o-independent escape of listeria monocytogenes from a primary vacuole in human epithelial cells.intracellular growth of listeria monocytogenes begins after lysis of the primary vacuole formed upon bacterial entry into a host cell. listeriolysin o (llo), a pore-forming hemolysin encoded by hly, is essential for vacuolar lysis in most cell types. however, in human epithelial cells, llo- mutants are capable of growth, suggesting that gene products other than llo are capable of mediating escape from a vacuole. in this study, we investigated the role of other bacterial gene products in lysis of ...19957591098
listeria monocytogenes can grow in macrophages without the aid of proteins induced by environmental stresses.listeria monocytogenes is a facultative intracellular pathogen which is able to survive and grow within phagocytic cells. some facultative intracellular bacteria have been shown to respond to the hostile environment within phagocytic cells by producing a set of stress proteins. since l. monocytogenes has a mechanism for intracellular survival that is distinct from those of other bacteria, we studied the phenotypic response of the bacterium to phagocytosis by macrophages. after phagocytosis of l. ...19957591111
listeria monocytogenes septicemia in a foal.listeria monocytogenes is rarely reported as a cause of septicemia in foals. in this case, the foal had diarrhea 2 weeks prior to the onset of signs of lethargy, high rectal temperature, and leukopenia with a left shift. listeria monocytogenes was isolated from the blood culture. the most commonly isolated organism causing septicemia in foals is escherichia coli. without the blood cultures, a definitive diagnosis would not have been possible.19957591928
the relationship between ecophysiology, indigenous microflora and growth of listeria monocytogenes in grass silage.the combined effect of the physical and chemical parameters (oxygen tension, ph and dry matter) influencing listeria monocytogenes growth and survival in silage were simultaneously studied in a model in vitro system. ensiled grass was exposed to a range of low oxygen concentrations, 0-5% v/v, and their effect was recorded with respect to acidification and microbial population dynamics of the epiphytic microflora, i.e. lactic acid bacteria, enterobacteria, yeasts, moulds and l. monocytogenes in g ...19957592109
differential activation of virulence gene expression by prfa, the listeria monocytogenes virulence regulator.prfa is a pleiotropic activator of virulence gene expression in the pathogenic bacterium listeria monocytogenes. several lines of evidence have suggested that a hierarchy of virulence gene activation by prfa exists. this hypothesis was investigated by assessing the ability of prfa to activate the expression of virulence gene fusions to lacz in bacillus subtilis. expression of prfa in this heterologous host was sufficient for activation of transcription at the hly, plca, mpl, and acta promoters. ...19957592422
organization and transcriptional analysis of the listeria phage a511 late gene region comprising the major capsid and tail sheath protein genes cps and tsh.a511 is a broad-host-range, virulent myovirus for listeria monocytogenes. the genes encoding major structural proteins of the capsid (cps) and tail sheath (tsh) were mapped to a 10.15-kb late gene fragment. we have determined the complete nucleotide sequence of this region and confirmed the identities of cps (48.7 kda) and tsh (61.3 kda) by n-terminal amino acid sequencing of both proteins. in addition, nine other open reading frames were identified. on the basis of amino acid sequence homologie ...19957592439
induction of cell-mediated immune responses to human immunodeficiency virus type 1 gag protein by using listeria monocytogenes as a live vaccine vector.cytolytic t cells, acting through cytokines or by direct lysis of infected target cells, have been shown to play a significant role in the control of viral infections and may be responsible for the prolonged asymptomatic phase following infection by hiv. accordingly, methods that can generate strong cell-mediated immune responses may be useful in the development of prophylactic and therapeutic vaccines against hiv. listeria monocytogenes is a gram-positive intracellular microorganism that elicit ...19957594479
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