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administration of superantigens protects mice from lethal listeria monocytogenes infection by enhancing cytotoxic t cells.superantigens stimulate t-cell-receptor vbeta-selective t-cell proliferation accompanying the release of cytokines, which may eventually protect the host from microbial infections. we investigated here whether superantigens can rescue the host from lethal bacterial infection. mice were pretreated with staphylococcus aureus enterotoxin b (seb) 1 and 2 days before bacterial infection, and the mortality of infected mice was assessed. seb pretreatment protected mice from lethal infection with lister ...200111598032
[listeria monocytogenes aortitis]. 200111599169
effect of sampling method on the representative recovery of microorganisms from the surfaces of aquacultured finfish.the objective of this study was to determine if a gentle rinse procedure was equivalent to the combination of excision and homogenization with a stomacher for the relative removal of various microorganisms from finfish fillets. fillets of hybrid striped bass and rainbow trout were obtained from local markets and sampled using three methods: rinse (r), excision followed by homogenization in a stomacher (s), and homogenization of fillets following a rinse (rs). microorganisms were enumerated on se ...200111601699
comparative evaluation of culture- and bax polymerase chain reaction-based detection methods for listeria spp. and listeria monocytogenes in environmental and raw fish samples.two commercial polymerase chain reaction (pcr)-based listeria detection systems, the bax for screening/listeria monocytogenes and the bax for screening/genus listeria, and a culture-based detection system, the biosynth l. monocytogenes detection system (lmds), were evaluated for their ability to detect l. monocytogenes and listeria spp. in raw ingredients and the processing environment. for detection of l. monocytogenes from raw fish, enrichment was performed in listeria enrichment broth (leb), ...200111601700
efficacy of chitosan, carvacrol, and a hydrogen peroxide-based biocide against foodborne microorganisms in suspension and adhered to stainless steel.the ability of natural compounds to inactivate foodborne organisms adhered to surfaces was investigated with the ultimate aim of replacing synthetic biocides by more environmentally friendly, natural alternatives. the antimicrobial efficacy of 0.5, 1.0, and 2.0% chitosan and spor-klenz rtu (a commercial biocide based on hydrogen peroxide and peroxyacetic acid) and 0.5, 1.25, and 2.0 mm carvacrol was determined at 20 degrees c against listeria monocytogenes, salmonella enterica serovar typhimuriu ...200111601703
efficacy of trisodium phosphate solutions in reducing listeria monocytogenes populations on chicken skin during refrigerated storage.chicken skin inoculated with l0(8) cfu/ml of listeria monocytogenes was dipped for 15 min in sterile water (control) and in 8, 10, or 12% trisodium phosphate (tsp) solutions. skin samples were stored at 2 degrees c for 5 days, with microbial monitoring on days 0, 1, 3, and 5 after treatment. compared to the water dip, all tsp treatments significantly (p < 0.05) reduced l monocytogenes populations on chicken skin. the concentration of the tsp was a significant factor in reducing the populations o ...200111601719
a possible regulatory role for the metal-binding domain of cada, the listeria monocytogenes cd2+-atpase.using the baculovirus/sf9 expression system, we produced cada and deltambd, a metal-binding domain, truncated cada. both proteins had the expected properties of p-type atpases: atp-induced cd2+ accumulation, cd2+-sensitive atp and pi phosphorylation and atpase activity. deltambd displayed lower initial transport velocity as well as lower maximal atpase activity than cada. mbd truncation flattened the cd2+ dependence of the atpase activity and increased apparent cd2+ affinity, suggesting a positi ...200111602255
[emerging new risks of food-borne infections]. 200111602389
inhibitory activity of honey against foodborne pathogens as influenced by the presence of hydrogen peroxide and level of antioxidant power.antimicrobial activity of honey has been attributed to hydrogen peroxide, which is produced by naturally occurring glucose oxidase, and phenolic compounds, although lethality of and inhibition by these and other components against microorganisms vary greatly, depending on the floral source of nectar. this study was undertaken to compare honeys from six floral sources for their inhibitory activity against escherichia coli o157:h7, salmonella typhimurium, shigella sonnei, listeria monocytogenes, s ...200111603859
random amplification of polymorphic dna typing of listeria monocytogenes isolated from meat.to investigate the epidemiological characteristics of listeria monocytogenes isolated from imported or domestic meats, l. monocytogenes was isolated and identified through biochemical and serological tests, and epidemiological analysis of the isolates was carried out through the random amplification of polymorphic dna (rapd) method. fifty-four isolates were identified as l. monocytogenes through biochemical tests, of which 36 (67%) were confirmed as serotype 1, and 18 (33%) were serotype 4, thro ...200111603860
transfer of eukaryotic expression plasmids to mammalian host cells by bacterial carriers.the concept of transkingom transfer of dna from bacteria to other organisms has recently been extended to include eukaryotic host cells. intracellular bacteria have been shown to transfer eukaryotic expression plasmids to mammalian host cells in vitro and in vivo. this can be used to induce immune responses towards protein antigens encoded by the plasmid, to complement genetic defects or even to direct the production of proteins in appropriate organs. the ease of generating such vehicles makes t ...200111604322
effects of vegetable type, package atmosphere and storage temperature on growth and survival of escherichia coli o157:h7 and listeria monocytogenes.the survival and growth of escherichia coli o157:h7 (atcc 43888 and nctc 12900) and listeria monocytogenes (atcc 19114 and nctc 11994) during storage (4 and 8 degrees c) on ready-to-use (rtu) packaged vegetables (lettuce, swedes (rutabaga), dry coleslaw mix, soybean sprouts) were studied. the vegetables were sealed within oriented polypropylene packaging film, and modified atmospheres developed in packs during storage due to produce respiration. survival and growth patterns were dependent on veg ...200111641769
epidural abscess and vertebral osteomyelitis caused by listeria monocytogenes: case report and literature review.a 69-y-old male with an epidural abscess and concomitant vertebral osteomyelitis caused by listeria monocytogenes is presented, together with a brief review of the literature. to our knowledge, no cases of epidural abscess and only 3 cases of osteomyelitis have previously been reported in association with this organism.200111669234
fulminant hepatitis b virus reactivation with concomitant listeriosis after fludarabine and rituximab therapy: case report.chronic hepatitis b infection poses a problem in patients with malignancies undergoing chemotherapy. not uncommonly, hepatitis b virus (hbv) reactivates during or soon after chemotherapy. we report a case of a woman with acute prolymphocytic leukemia who received chemotherapy containing fludarabine and cyclophosphamide, followed by the cd 20 monoclonal antibody, rituximab. she developed fatal reactivation of hepatitis b with fulminant liver failure 3 months after completing treatment. listeria m ...200111669307
virologic and immunologic parameters that predict clinical response of aids-associated kaposi's sarcoma to highly active antiretroviral therapy.the purpose of the work was to assess the predictive value of biologic factors on the efficacy of highly active antiretroviral therapy alone or combined with chemotherapy on aids-associated kaposi's sarcoma. twenty-six aids-kaposi's sarcoma patients who started therapy with protease inhibitors were investigated. no baseline chemotherapy was associated with less severe initial clinical status. median follow-up was 652 d. the main outcome measures were as follows: best kaposi's sarcoma clinical re ...200111676823
in vitro transcription of prfa-dependent and -independent genes of listeria monocytogenes.in vitro transcription starting from the promoters of the listeria monocytogenes genes hly, plca, acta, mpl, prfa and iap has been studied. whereas transcription from phly, pplca and pacta is strictly prfa-dependent, that from piap, pprfa1/2 and, unexpectedly, also from pmpl is independent. initiation of in vitro transcription at all tested promoters except pprfa requires high concentrations of atp but not gtp. the nucleotides required in higher concentrations for efficient in vitro transcriptio ...200111679071
pyrosequencing as a method for grouping of listeria monocytogenes strains on the basis of single-nucleotide polymorphisms in the inlb gene.by using pyrosequencing (i.e., sequencing by synthesis) 106 strains of different serovars of listeria monocytogenes were rapidly grouped into four categories based on nucleotide variations at positions 1575 and 1578 of the inlb gene. strains of serovars 1/2a and 1/2c constituted one group, and strains of serovars 1/2b and 3b constituted another group, whereas serovar 4b strains were separated into two groups.200111679367
comparative genomics of listeria species.listeria monocytogenes is a food-borne pathogen with a high mortality rate that has also emerged as a paradigm for intracellular parasitism. we present and compare the genome sequences of l. monocytogenes (2,944,528 base pairs) and a nonpathogenic species, l. innocua (3,011,209 base pairs). we found a large number of predicted genes encoding surface and secreted proteins, transporters, and transcriptional regulators, consistent with the ability of both species to adapt to diverse environments. t ...200111679669
listeria monocytogenes response regulators important for stress tolerance and pathogenesis.environmental sensing by two-component signal transduction systems is likely to play a role for growth and survival of listeria monocytogenes both during transmission in food products and within a host organism. two-component systems typically consist of a membrane-associated sensor histidine kinase and a gene regulatory protein, the response regulator (rr). we have identified seven putative rr genes in l. monocytogenes lo28 by pcr using degenerate oligonucleotide primers. by insertional inactiv ...200111682188
rapd analysis, serotyping, and esterase typing indicate that the population of listeria monocytogenes strains recovered from cheese and from patients with listeriosis in belgium are different.populations of listeria monocytogenes strains isolated in belgium from cheese and from patients with listeriosis were characterised by randomly amplified polymorphic dna (rapd) analysis using two 10-mers primers (opa-04 and opa-13). high discrimination levels were obtained with each of these primers alone (discrimination indices (di) of 0.899 and 0.935 for opa13 and opa04, respectively) or in combination (di of 0.960). the clustering of strains obtained by rapd was compared with a clustering pre ...200111683471
rapidly growing tumor-like brain lesion.listeria monocytogenes accounts for 8-11% of the cases of bacterial meningitis which is associated with high mortality in patients with serious underlying diseases or those receiving immunosuppressive treatment. brain abscess due to l. monocytogenes is a very rare occurrence. the case reported here concerns a 54-year-old female patient with a rapidly growing tumor-like brain lesion. l. monocytogenes type 4b could be cultured from blood and brain biopsy. despite antimicrobial therapy with ampicil ...200111688907
[spontaneous bacterial peritonitis caused by listeria monocytogenes in a patient with liver cirrhosis]. 200111692785
evaluation of surface contamination and the presence of listeria monocytogenes in fish processing factories.the main objective of this study was to determine the level of surface contamination in fish processing factories and the presence of listeria in the factory environment and products. another objective was evaluation of the different hygiene-monitoring methods. total aerobic heterotrophic and enterobacteria, yeast and mold samples were collected and atp levels measured in 28 factories. the number of well or adequately washed and disinfected factories was small (2 of 28), in terms of total aerobi ...200111347992
enhanced inhibition of listeria monocytogenes and salmonella enteritidis in meat by combinations of sodium lactate and diacetate.the antimicrobial activities of sodium lactate (sl) and sodium acetate (sa) are well documented, but there is limited information on the effect of their combination or of the combination of sl and sodium diacetate (sda) on survival and growth of listeria monocytogenes and salmonellae in meat. effects of sl (1.8 and 2.5%), sda (0.1 and 0.2%), or sa (0.2%) and their combinations on the behavior of l monocytogenes and salmonella enterica serovar enteritidis were investigated in sterile comminuted b ...200111347993
random amplified polymorphic dna typing applied to the study of cross-contamination by listeria monocytogenes in processed food products.the presence of listeria spp. was investigated in 369 samples of cooked meat products and 52 of smoked salmon. incidences of 17.6% for cooked meat and 38.5% for smoked salmon samples were found. all listeria monocytogenes isolates (34 from meat products and 16 from smoked salmon) were typed serologically and by random amplified polymorphic dna (rapd) typing using primers hlwl74 (5'-acgtatctgc-3'), hlwl85 (5'-acaactgctc-3'), and omp-01 (5'-gti'ggtggct-3'). strains from cooked meat products were c ...200111348007
effects of epiphytic enterobacteriaceae and pseudomonads on the growth of listeria monocytogenes in model media.four enterobacteriaceae (enterobacter agglomerans and rhanella aquatilis) and six pseudomonads (pseudomonas fluorescens, pseudomonas chlororaphis, pseudomonas putida) isolated from minimally processed green endive were coinoculated at 10 degrees c with listeria monocytogenes in a minimal medium. pseudomonads did not modify the growth of l. monocytogenes, whereas enterobacteriaceae reduced its maximal population by 2 to 3 log cfu/ml. the same effect was observed in a diluted yeast extract medium ...200111348008
immunization of mice with lipopeptide antigens encapsulated in novel liposomes prepared from the polar lipids of various archaeobacteria elicits rapid and prolonged specific protective immunity against infection with the facultative intracellular pathogen, listeria monocytogenes.protective immunity to intracellular bacterial pathogens usually requires the participation of specific cd8+ t cells. natural exposure of the host to sublethal infection, or vaccination with attenuated live vaccines are the most effective means of eliciting prolonged protective cell-mediated immunity against this class of pathogens. the ability to replace these immunization strategies with defined sub-unit vaccines would represent a major advance for clinical vaccinology. the present study exami ...200111348718
gut colonization of mice with acta-negative mutant of listeria monocytogenes can stimulate a humoral mucosal immune response.we used listeria monocytogenes, a gram-positive, facultative intracellular bacterium, to study the gut mucosal immune responses following oral infection. we employed a germfree (gf) mouse model to try to accentuate the development of a humoral mucosal immune response in the gut, and we used oral colonization with one of the mutants, acta-negative (deltaacta) l. monocytogenes, to restrict infection largely to the gut. the deltaacta mutant was able to colonize the intestinal mucosa of formerly gf ...200111349011
calprotectin expression inhibits bacterial binding to mucosal epithelial cells.squamous mucosal epithelial cells constitutively express calprotectin in the cytoplasm. to study how this antimicrobial protein complex confers epithelial resistance to invading bacteria, an epithelial cell line was stably transfected to express the calprotectin complex. cells expressing calprotectin resist invasion by listeria monocytogenes and salmonella enterica serovar typhimurium. calprotectin expression was accompanied by altered actin organization, increased alpha3 integrin expression, an ...200111349032
characterization of the groesl operon in listeria monocytogenes: utilization of two reporter systems (gfp and hly) for evaluating in vivo expression.the ability of intracellular pathogens to sense and adapt to the hostile environment of the host is an important factor governing virulence. we have sequenced the operon encoding the major heat shock proteins groes and groel in the gram-positive food-borne pathogen listeria monocytogenes. the operon has a conserved orientation in the order groes groel. upstream of groes and in the opposite orientation is a gene encoding a homologue of the bacillus subtilis protein ydil, while downstream of groel ...200111349060
gene fragments distinguishing an epidemic-associated strain from a virulent prototype strain of listeria monocytogenes belong to a distinct functional subset of genes and partially cross-hybridize with other listeria species.most major food-borne outbreaks of listeriosis in europe and in the united states have been caused by genetically closely related listeria monocytogenes strains of serotype 4b. in order to assess whether genomic loci exist that could underlie this increased epidemic potential, we subtracted the genome of the virulent prototype l. monocytogenes strain egd from a prototype epidemic strain. a total of 39 dna fragments corresponding to 20% of an estimated total of 150 to 190 kb of differential genom ...200111349066
nitric oxide is protective in listeric meningoencephalitis of rats.the bacterium listeria monocytogenes causes meningoencephalitis in humans. in rodents, listeriosis is associated with granulomatous lesions in the liver and the spleen, but not with meningoencephalitis. here, infant rats were infected intracisternally to generate experimental listeric meningoencephalitis. dose-dependent effects of intracisternal inoculation with l. monocytogenes on survival and activity were noted; 10(4) l. monocytogenes organisms induced a self-limiting brain infection. bacteri ...200111349080
gp96-peptide vaccination of mice against intracellular bacteria.this work demonstrates that gp96 preparations isolated from cells infected with intracellular bacteria induce cytotoxic t-lymphocyte responses and confer protection. our findings extend previous reports on the immunogenicity of gp96-associated peptides to antigens derived from intracellular bacteria. immunization with gp96 may therefore represent a promising vaccination strategy against bacterial pathogens.200111349093
[genetic mechanisms of listeria monocytogenes virulence].current data on genetic determinants of virulence in listeria monocytogenes and on factors affecting their expression are reviewed. the role of the prfa protein, the only known transcriptional regulator that directly affects virulence gene expression and mechanisms responsible for the activity and/or concentration of this protein in the cell are considered. detailed information of outer signals modulating the level of virulence factor expression is provided. data that favor the involvement of au ...200111357361
listeriolysin--a useful cytolysin. 200111357827
the act operon controls the level and time of c-signal production for myxococcus xanthus development.the c-signal is a morphogen that controls the assembly of fruiting bodies and the differentiation of myxospores. production of this signal, which is encoded by the csga gene, is regulated by the act operon of four genes that are co-transcribed from the same start site. the act a and act b genes regulate the maximum level of the c-signal, which never rises above one-quarter of the maximum wild-type level of csga protein in null mutants of either gene. the act a and act b mutants have the same dev ...200111359579
uva exposure affects uvb and cis-urocanic acid-induced systemic suppression of immune responses in listeria monocytogenes-infected balb/c mice.ultraviolet radiation can inhibit immune responses locally as well as systemically. such effects have been measured in animals and humans exposed to ultraviolet b (wavelength 280-315 nm) (uvb) and ultraviolet a (315-400 nm) (uva). the precise wavelength dependence is important for the identification of possible molecular targets and for assessments of risk of different artificial uv sources and solar uv. in such analyses, it is commonly assumed that radiation energy from each wavelength contribu ...200111332040
evolution and function of the neisserial dam-replacing gene.phase variation through slippage-like mechanisms involving homopolymeric tracts depends in part on the absence of dam-methylase in several pathogenic isolates of neisseria meningitidis. in dam-defective strains drg (dam-replacing gene), flanked by pseudo-transposable small repeated elements (sres), replaced dam. we demonstrate that drg encodes a restriction endonuclease (nmebii) that cleaves 5'-gmeatc-3'. drg is also present in 50% of neisseria lactamica strains, but in most of them it is inacti ...200111334887
stimulation of myelopoiesis in listeria monocytogenes-infected mice by an aggregated polymer isolated from aspergillus oryzae.in this work, we investigated the effects of the proteic aggregated polymer of magnesium ammonium phospholinoleate-palmitoleate anhydride (mapa) isolated from aspergillus oryzae on the growth and differentiation of bone marrow granulocyte-macrophage progenitor cells (cfu-gm) in listeriamonocytogenes-infected mice. a significant reduction in the cfu-gm number was observed in the initial phase of infection with a sublethal dose of listeria. treatment of mice with 0.5, 2.0 and 5.0 mg/kg mapa for 7 ...200111339624
cutting edge: antigen-independent cd8 t cell proliferation.recent analyses of cd8 t cell responses to listeria monocytogenes infection demonstrate that the duration of in vivo t cell proliferation is not determined by the amount or duration of ag presentation. however, the extent to which t lymphocytes are capable of proliferating in the absence of ag is unknown. herein we demonstrate that cd8 t lymphocytes undergo up to eight rounds of proliferation in the absence of ag following transient, 2.5-h in vitro antigenic stimulation. ag-independent expansion ...200111342598
two novel genes find and lind differentially expressed in deactivated and listeria-infected human macrophages.deactivation of macrophage functions plays an important role in human infectious and inflammatory diseases. in this study, differential-display rt-pcr was used to analyze the gene expression of human mononuclear phagocytes deactivated with interleukin (il)-4, il-10, and dexamethasone (dex), in the absence and presence of infection with listeria monocytogenes (listeria). two novel differentially expressed mrna species were discovered: find (il-four induced) was upregulated with il-4 but down-regu ...200111345586
phagocytosis and clearance of apoptotic cells is mediated by mer.apoptosis is fundamental to the development and maintenance of animal tissues and the immune system. rapid clearance of apoptotic cells by macrophages is important to inhibit inflammation and autoimmune responses against intracellular antigens. here we report a new function for mer, a member of the axl/mer/tyro3 receptor tyrosine kinase family. mer(kd) mice with a cytoplasmic truncation of mer had macrophages deficient in the clearance of apoptotic thymocytes. this was corrected in chimaeric mic ...200111346799
from evil to good: a cytolysin in vaccine development.current vaccination strategies mainly target antigens into the phagosomal, major histocompatibility complex class ii antigen-processing pathway and thus lead predominantly to humoral immune responses. the elicitation of cytotoxic t-cell responses instead requires introduction of antigens into the cytosol of professional antigen-presenting cells (apcs). the intracellular bacterium listeria monocytogenes gains access to the host cell cytosol by means of a cytolysin, listeriolysin o. vaccine resear ...200111166239
use of live bacterial vaccine vectors for antigen delivery: potential and limitations.most infectious agents are restricted to the mucosal membranes or their transit through the mucosa constitutes a critical step in the infection process. therefore, the elicitation of an efficient immune response, not only at systemic, but also at mucosal level, after vaccination is highly desirable, representing a significant advantage in order to prevent infection. this goal can be only achieved, when the vaccine formulation is administered by the mucosal route. however, soluble antigens given ...200111166877
the acid-stress response in lactobacillus sanfranciscensis cb1.lactobacillus sanfranciscensis cb1, an important sourdough lactic acid bacterium, can withstand low ph after initial exposure to sublethal acidic conditions. the sensitivity to low ph varied according to the type of acid used. treatment of lb: sanfranciscensis cb1 with chloramphenicol during acid adaptation almost completely eliminated the protective effect, suggesting that induction of protein synthesis was required for the acid-tolerance response. two constitutively acid-tolerant mutants, cb1- ...200111429463
listeria pathogenesis and molecular virulence determinants.the gram-positive bacterium listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individuals. clinical manifestations of invasive listeriosis are usually severe and include abortion, sepsis, and meningoencephalitis. listeriosis can also manifest as a febrile gastroente ...200111432815
microbial genomics. dynamic duos. 200111728863
lifestyles of the intracellular. 200111728864
actin-based motility of intracellular microbial pathogens.a diverse group of intracellular microorganisms, including listeria monocytogenes, shigella spp., rickettsia spp., and vaccinia virus, utilize actin-based motility to move within and spread between mammalian host cells. these organisms have in common a pathogenic life cycle that involves a stage within the cytoplasm of mammalian host cells. within the cytoplasm of host cells, these organisms activate components of the cellular actin assembly machinery to induce the formation of actin tails on th ...200111729265
first report of an outbreak of ovine septicaemic listeriosis in saudi arabia.although a case of human listeriosis has recently been reported in saudi arabia, the disease has not been reported in animals to date. the authors describe an outbreak of septicaemic listeriosis in sheep, which occurred during winter. adult animals and pregnant ewes were principally affected, with a morbidity rate of 7.1% and a mortality rate of 2.4%; no abortions were recorded during the outbreak. clinical signs included inappetence, weakness, fever, respiratory distress, keratoconjunctivitis a ...200111732420
[notification according to the law for protection against infections].since january 1st 2001, the law for protection against infections decrees the duty of notification along two tracks, on the one hand by notification of infectious diseases and on the other hand by reporting the pathogens. however, the names of pathogens change due to scientific progress. furthermore, these names include in some cases not only harmful agents of infectious diseases but also inoffensive organisms, i. e. giardia lamblia. there are also problems in the notification of other pathogens ...200111735068
sample preparation methods for pcr detection of escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes on beef chuck shoulder using a single enrichment medium.to improve the utility of the polymerase chain reaction (pcr) for food samples, methods for preparing template dna were developed to remove pcr inhibitors. beef chuck shoulder medallions, artificially contaminated, individually or in combination, with escherichia coli serotype o157:h7 strain fsis 45753-35, salmonella typhimurium dt104 strain 13hp, or listeria monocytogenes strain scott a at concentrations of 10, 1 and 0.5 cfu/cm(2)were swabbed with a sponge, and the sponges were enriched for 18 ...200111735298
rapid detection of listeria monocytogenes in foods, by a combination of pcr and dna probe.listeria monocytogenes is a frequent contaminant of water and foods. its rapid detection is needed before some foods can be prepared for marketing. in this work l. monocytogenes has been searched for in foods, by a combination of polymerase chain reaction (pcr) and a dna probe. both pcr and the probe were prepared for recognizing a specific region of the internalin gene, which is responsible for the production of one of the most important pathogenic factors of listeria. the combined use of pcr a ...200111735299
bacterial meningitis: current controversies in approaches to treatment.acute bacterial meningitis continues to be a disease with unacceptably high mortality and morbidity rates in both adults and children worldwide, despite advances in antibacterial therapy. death or permanent disability occurs frequently. the causative organism varies with age, immune function and immunisation status. infection with neisseria meningitidis, streptococcus pneumoniae and haemophilus influenzae type b (hib) is associated with the majority of cases, with listeria monocytogenes and stre ...200111735611
a role for acta in epithelial cell invasion by listeria monocytogenes.we assessed the role of the actin-polymerizing protein, acta, in host cell invasion by listeria monocytogenes. an in frame deltaacta mutant was constructed in a hyperinvasive strain of prfa* genotype, in which all genes of the prfa-dependent virulence regulon, including acta, are highly expressed in vitro. loss of acta production in prfa* bacteria reduced entry into caco-2, hela, mdck and vero epithelial cells to basal levels. reintroduction of acta into the deltaacta prfa* mutant fully restored ...200111736996
synergy between the n- and c-terminal domains of inlb for efficient invasion of non-phagocytic cells by listeria monocytogenes.inlb is a listeria monocytogenes protein promoting entry in non-phagocytic cells, and has been shown recently to activate the hepatocyte growth factor receptor (hgfr or met). the n-terminal domain of inlb (lrrs) binds and activates met, whereas the c-terminal domain of inlb (gw modules) mediates loose attachment of inlb to the listerial surface. as hgf activation of met is tightly controlled by glycosaminoglycans (gags), we tested if gags also modulate the met-inlb interactions. we show that inl ...200111737639
endogenous serratia marcescens endophthalmitis with dark hypopyon: case report and review.a case of endogenous serratia marcescens endophthalmitis in a patient with diabetes, end-stage renal disease, and an indwelling venous catheter is reported. the patient presented with a tan hypopyon and elevated intraocular pressure. diagnosis was established by positive blood, vitreous, conjunctival, and catheter tip cultures. after a deteriorating course the eye was enucleated. gross and histopathologic examination revealed the presence of a dark hypopyon with iris necrosis and pigment dispers ...200111738433
immunoproteasomes largely replace constitutive proteasomes during an antiviral and antibacterial immune response in the liver.the proteasome is critically involved in the production of mhc class i-restricted t cell epitopes. proteasome activity and epitope production are altered by ifn-gamma treatment, which leads to a gradual replacement of constitutive proteasomes by immunoproteasomes in vitro. however, a quantitative analysis of changes in the steady state subunit composition of proteasomes during an immune response against viruses or bacteria in vivo has not been reported. here we show that the infection of mice wi ...200111739503
a sigma(54)-dependent pts permease of the mannose family is responsible for sensitivity of listeria monocytogenes to mesentericin y105.sensitivity of listeria monocytogenes to the bacteriocin mesentericin y105 was previously shown to be dependent on the sigma(54) subunit of the rna polymerase. this points towards expression of particular sigma(54)-dependent genes. the present study describes first, manr, a new sigma(54)-associated activator, and second, ell(t)(man), a new sigma(54)-dependent pts permease of the mannose family, both involved in sensitivity to mesentericin y105, since interruption of their corresponding genes led ...200111739758
the effect of inoculum size and sublethal injury on the ability of listeria monocytogenes to initiate growth under suboptimal conditions.to investigate the effect of inoculum size and physiological state on the ability of listeria monocytogenes cells to initiate growth under suboptimal conditions of salt concentration and ph.200111696096
evaluation of a spray-dried lacticin 3147 powder for the control of listeria monocytogenes and bacillus cereus in a range of food systems.the potential of a powdered preparation of the bacteriocin, lacticin 3147, was investigated for the inhibition of listeria monocytogenes and bacillus cereus.200111696102
listeria monocytogenes infection overcomes the requirement for cd40 ligand in exogenous antigen presentation to cd8(+) t cells.in vivo priming of cd8(+) t lymphocytes against exogenously processed model ags requires cd4(+) t cell help, specifically interactions between cd40 ligand (cd40l) expressed by activated cd4(+) t cells and cd40, which is present on professional apc such as dendritic cells (dcs). to address this issue in the context of bacterial infection, we examined cd40l-cd40 interactions in cd8(+) t cell priming against an exogenously processed, nonsecreted bacterial ag. cd40l interactions were blocked by in v ...200111698431
role of cd28 for the generation and expansion of antigen-specific cd8(+) t lymphocytes during infection with listeria monocytogenes.infection of mice with the intracellular bacterium listeria monocytogenes results in a strong cd8(+) t cell response that is critical for efficient control of infection. we used cd28-deficient mice to characterize the function of cd28 during listeria infection, with a main emphasis on listeria-specific cd8(+) t cells. frequencies and effector functions of these t cells were determined using mhc class i tetramers, single cell ifn-gamma production and listeria-specific cytotoxicity. during primary ...200111698433
prevalence of foodborne pathogens in bulk tank milk.bulk tank milk from 131 dairy herds in eastern south dakota and western minnesota was examined for the presence of for foodborne pathogens. campylobacter jejuni, shiga-toxin producing escherichia coli, listeria monocytogenes, salmonella spp., and yersinia enterocolitica were detected in 9.2, 3.8, 4.6, 6.1, and 6.1% of bulk tank milk samples, respectively. thirty-five of 131 (26.7%) bulk tank milk samples contained one or more species of pathogenic bacteria. isolates of salmonella belonged to gro ...200111699446
two consecutive nationwide outbreaks of listeriosis in france, october 1999-february 2000.in france, listeriosis surveillance is based on mandatory notification of all culture-confirmed cases, with systematic typing of isolates and routine collection of the patient's food history. from october 1999 to march 2000, two outbreaks of listeriosis were detected through this enhanced surveillance system. in outbreak 1, analysis of the food histories of cases suggested brand x "rillettes," a pâté-like meat product, as the vehicle of infection, and the outbreak strain of listeria monocytogene ...200111700249
svpa, a novel surface virulence-associated protein required for intracellular survival of listeria monocytogenes.a previously unknown protein, designated svpa (surface virulence-associated protein) and implicated in the virulence of the intracellular pathogen listeria monocytogenes, was identified. this 64 kda protein, encoded by svpa, is both secreted in culture supernatants and surface-exposed, as shown by immunogold labelling of whole bacteria with an anti-svpa antibody. analysis of the peptide sequence revealed that svpa contains a leader peptide, a predicted c-terminal transmembrane region and a posit ...200111700342
intestinal infection of balb/c mice with yersinia enterocolitica o9 causes major modifications in phenotype and functions of spleen cells.yersinia enterocolitica serotype o9 may cause a persistent intestinal infection with few or no symptoms in humans and in balb/c mice. the present study demonstrated profound alterations in the immune status of balb/c mice infected with y. enterocolitica o9. infected mice developed splenomegaly and phenotypic analysis of spleen cells revealed increases in cd3+ total t cells, cd4+ helper t cells, cd8+ cytotoxic t cells and cd11b+ phagocytic cells. spleen cells from infected mice exhibited impaired ...200111700368
exaggerated proinflammatory and th1 responses in the absence of gamma/delta t cells after infection with listeria monocytogenes.while gamma/delta t cells are involved in host defense and immunopathology in a variety of infectious diseases, their precise role is not yet clearly defined. in the absence of gamma/delta t cells, mice die after infection with a dose of listeria monocytogenes that is not lethal in immunologically intact animals. morbidity might result from insufficient levels of cytokines normally produced by gamma/delta t cells or conversely from an excess of cytokines due to a lack of down-regulation of the i ...200111705890
effect of 6-hydroxydopamine on host resistance against listeria monocytogenes infection.recent studies have shown that immunocompetent cells bear receptors of neuropeptides and neurotransmitters and that these ligands play roles in the immune response. in this study, the role of the sympathetic nervous system in host resistance against listeria monocytogenes infection was investigated in mice pretreated with 6-hydroxydopamine (6-ohda), which destroys sympathetic nerve termini. the norepinephrine contents of the plasma and spleens were significantly lower in 6-ohda-treated mice than ...200111705892
tolerance or immunity to a tumor antigen expressed in somatic cells can be determined by systemic proinflammatory signals at the time of first antigen exposure.mice transgenic for the e7 tumor ag of human papillomavirus type 16, driven from a keratin 14 promoter, express e7 in keratinocytes but not dendritic cells. grafted e7-transgenic skin is not rejected by e7-immunized mice that reject e7-transduced transplantable tumors. rejection of recently transplanted e7-transgenic skin grafts, but not of control nontransgenic grafts or of established e7-transgenic grafts, is induced by systemic administration of live or killed listeria monocytogenes or of end ...200111714778
two listeria monocytogenes vaccine vectors that express different molecular forms of human papilloma virus-16 (hpv-16) e7 induce qualitatively different t cell immunity that correlates with their ability to induce regression of established tumors immortalized by hpv-16.two recombinant listeria monocytogenes (rlm) strains were produced that secrete the human papilloma virus-16 (hpv-16) e7 protein expressed in hpv-16-associated cervical cancer cells. one, lm-e7, expresses and secretes e7 protein, whereas a second, lm-llo-e7, secretes e7 as a fusion protein joined to a nonhemolytic listeriolysin o (llo). lm-llo-e7, but not lm-e7, induces the regression of the e7-expressing tumor, tc-1, established in syngeneic c57bl/6 mice. both recombinant e7-expressing rlm vacc ...200111714814
immunization with gp96 from listeria monocytogenes-infected mice is due to n-formylated listerial peptides.n-formylated (n-f-met) peptides derived from proteins of the intracellular bacterium listeria monocytogenes generate a protective, h2-m3-restricted cd8 t cell response in c57bl/6 mice. n-f-met peptide-specific ctl were generated in vitro when mice previously immunized with gp96 isolated from donor mice infected with l. monocytogenes were stimulated with these peptides. no significant peptide-specific ctl activity was observed in mice immunized with gp96 from uninfected animals. masses correspond ...200111714815
prevalence and characterization of listeria monocytogenes in the feces of healthy austrians.the aims of the study were to determine the prevalence of listeria monocytogenes in the feces of healthy austrians and to characterize the isolates by various typing methods. stool specimens from 505 healthy volunteers from the tyrol were tested for the presence of l. monocytogenes using cold enrichment for 6 months and five different detection methods: conventional plating onto palcam and rapid'l.mono agar, immunomagnetic separation (ims) followed by conventional plating, enzyme-linked fluoresc ...200111715752
detection of listeria monocytogenes by polymerase chain reaction oriented to inlb gene.primers were designed for the detection of listeria monocytogenes by the polymerase chain reaction oriented to specific sequences of the inlb gene encoding an internalin. at optimized reaction conditions, 100% sensitivity (on a panel of 33 strains of l. monocytogenes) and 100% specificity (on panels of 15 strains of other listeria spp. and 41 other bacteria), were determined for the inlb-l/r primers. the detection limit of pcr with these primers was 10(4) cfu/ml and was not affected by up to 10( ...200111718370
cloning and characterization of m.lmoa118i, a novel dna:m4c methyltransferase from the listeria monocytogenes phage a118, a close homolog of m.ngomxv.a homolog of m.ngomxv dna:m4c methyltransferase has been identified among the open reading frames deduced from the genomic sequence of listeria monocytogenes phage a118 [loessner et al., 2000]. the gene coding for this putative protein has been cloned in escherichia coli and its enzymatic activity in vivo in this host have been analyzed. remarkably, despite m.ngomxv and m.lmoa118i exhibit high sequence similarity (58% identical and 19% conservatively substituted residues), their target preferenc ...200111720310
uptake and killing of listeria monocytogenes by normal human peripheral blood granulocytes and monocytes as measured by flow cytometry and cell sorting.cellular components of innate immunity (nk cells, monocytes and granulocytes) play an important role in early resistance to listeria monocytogenes in the mouse model. minimally invasive methods of measuring the bacteriocidal capacity of these cells may be useful as a biomarker of susceptibility in humans. a technique was developed whereby the uptake and survival of l. monocytogenes could be measured in human granulocytes and monocytes using small volumes of peripheral blood. this method used flo ...200111720818
effects of intermediate filaments on actin-based motility of listeria monocytogenes.how does subcellular architecture influence the intracellular movements of large organelles and macromolecular assemblies? to investigate the effects of mechanical changes in cytoplasmic structure on intracellular motility, we have characterized the actin-based motility of the intracellular bacterial pathogen listeria monocytogenes in normal mouse fibroblasts and in fibroblasts lacking intermediate filaments. the apparent diffusion coefficient of l. monocytogenes was two-fold greater in vimentin ...200111720985
priming of memory but not effector cd8 t cells by a killed bacterial vaccine.killed or inactivated vaccines targeting intracellular bacterial and protozoal pathogens are notoriously ineffective at generating protective immunity. for example, vaccination with heat-killed listeria monocytogenes (hklm) is not protective, although infection with live l. monocytogenes induces long-lived, cd8 t cell-mediated immunity. we demonstrate that hklm immunization primes memory cd8 t lymphocyte populations that, although substantial in size, are ineffective at providing protection from ...200111721060
an antibody-immobilized capillary column as a bioseparator/bioreactor for detection of escherichia coil o157:h7 with absorbance measurement.a capillary-column-based bioseparator/bioreactor was developed for detection of escherichia coli o157:h7 by chemically immobilizing anti-e. coli o157:h7 antibodies onto the inner wall of the column, forming the "sandwich" immunocomplexes (immobilized antibody-e. coli o157: h7-enzyme-labeled antibody) after the sample and the enzyme-labeled antibody passed through the column and detecting the absorbance of the product in the bioreactor with an optical detector. the effects of the blocking agent, ...200111721916
behaviour of listeria monocytogenes in packaged fresh mushrooms (agaricus bisporus).the aim of this study was to evaluate the potential of listeria monocytogenes to grow in mushrooms packaged in two different types of pvc films when stored at 4 degrees c and 10 degrees c.200111722656
adsorption of biosurfactant on solid surfaces and consequences regarding the bioadhesion of listeria monocytogenes lo28.the influence of biosurfactant compounds produced by a strain of pseudomonas fluorescens on the adhesion of listeria monocytogenes lo28 to polytetrafluoroethylene (ptfe) and aisi 304 stainless steel surfaces was investigated.200111722659
molecular epidemiology of listeria monocytogenes isolates collected from the environment, raw meat and raw products in two poultry- and pork-processing plants.in order to study the transmission of listeria monocytogenes in a poultry and a pork meat plant, we analysed the contamination by this pathogen over several months.200111722667
listeria keratitis in a horse.listeria monocytogenes is ubiquitous in the environment but is rarely reported as a cause of keratitis in animals. in this case, a mare was presented with epiphora and evidence of pain in the right eye. listeria monocytogenes was isolated from a corneal lesion, and bacteria were also seen in the cytologic evaluation. this is the first reported case of ulcerative keratitis associated with l. monocytogenes in a horse.200111722787
molecular typing by pulsed-field gel electrophoresis of spanish animal and human listeria monocytogenes isolates.a total of 153 strains of listeria monocytogenes isolated from different sources (72 from sheep, 12 from cattle, 18 from feedstuffs, and 51 from humans) in spain from 1989 to 2000 were characterized by pulsed-field gel electrophoresis. the strains of l. monocytogenes displayed 55 pulsotypes. the 84 animal, 51 human, and 18 feedstuff strains displayed 31, 29, and 7 different pulsotypes, respectively, indicating a great genetic diversity among the spanish l. monocytogenes isolates studied. l. mono ...200111722943
validation of apple cider pasteurization treatments against escherichia coli o157:h7, salmonella, and listeria monocytogenes.time and temperature pasteurization conditions common in the wisconsin cider industry were validated using a six-strain cocktail of escherichia coli o157:h7 and acid-adapted e. coli o157:h7 in ph- and degrees brix-adjusted apple cider. strains employed were linked to outbreaks (atcc 43894 and 43895, c7927, and usda-fsis-380-94) or strains engineered to contain the gene for green fluorescent protein (pgfp atcc 43894 and pgfp atcc 43889) for differential enumeration. survival of salmonella spp. (c ...200111726144
organic acids and their salts as dipping solutions to control listeria monocytogenes inoculated following processing of sliced pork bologna stored at 4 degrees c in vacuum packages.postprocessing contamination of cured meats with listeria monocytogenes has become a major concern for the meat processing industry and an important food safety issue. this study evaluated aqueous dipping solutions of organic acids (2.5 or 5% lactic or acetic acid) or salts (2.5 or 5% sodium acetate or sodium diacetate, 5 or 10% sodium lactate, 5% potassium sorbate or potassium benzoate) to control l. monocytogenes on sliced, vacuum-packaged bologna stored at 4 degrees c for up to 120 days. orga ...200111726150
reduction of listeria monocytogenes on green peppers (capsicum annuum l.) by gaseous and aqueous chlorine dioxide and water washing and its growth at 7 degrees c.reduction of listeria monocytogenes scott a on uninjured and injured surfaces of green peppers after 0.3- and 3-mg/ liter gaseous and aqueous clo2 treatment and water washing for 10 min at 20 degrees c was studied. growth of the l. monocytogenes untreated or treated with 0.6 mg/liter clo2 gas for 30 min at 20 degrees c on green peppers also was investigated. a membrane-surface-plating method was used for resuscitation and enumeration of l monocytogenes treated with clo2. the bacterial viability ...200111726151
detection of heat injury in listeria monocytogenes scott a.methods of detecting live pathogens in foods that may be growth inhibited following heat treatment are essential to food safety. among the techniques available, reverse transcription polymerase chain reaction (rt-pcr) amplification of messenger rna from heat-injured listeria monocytogenes scott a is preferable to direct pcr in an attempt to avoid false positives from dead cells. the rt-pcr has a detection limit of 3 x 10(6) cfu/g, compared to 3 cfu/g for untreated controls, but may not be suitab ...200111726152
combination of immunomagnetic separation and polymerase chain reaction for the simultaneous detection of listeria monocytogenes and salmonella spp. in food samples.a method that combined the immunomagnetic separation (ims) technique and the multiplex polymerase chain reaction (pcr) method (i.e., the ims-mpcr method) was developed for simultaneous detection of listreria monocytogenes and salmonella spp. in food samples. when only the multiplex pcr method was used, it was found that if cell numbers of each of the two target organisms (l. monocytogenes and salmonella spp.) were above the detection limit, but differed by more than 2 logs-e.g., n x 10(7) to n x ...200111726153
evaluation of universal preenrichment broth for growth of heat-injured pathogens.universal preenrichment broth (upb) was developed to enable enrichment of injured foodborne pathogens of different genera simultaneously in lieu of having to undergo separate simultaneous enrichment cultures for subsequent detection or isolation of each pathogen. enrichment conditions in upb for growth of injured pathogens to populations that will enable pathogen detection by rapid immuno-based or polymerase chain reaction (pcr)-based assays have not been defined. hence, studies were done to det ...200111726154
formulations and processing of yogurt affect the microbial quality of carbonated yogurt.carbonation, flavor, culture type, ph, and storage time were varied to investigate the effects of these variables and their interactions on the growth of both typical and nontypical yogurt cultures and some contaminating bacteria. two types of yogurt cultures (yc-470 and yc-180) were used as the source of typical yogurt bacteria, streptococcus thermophilus and lactobacillus delbrueckii subsp. bulgaricus. in addition, lactobacillus acidophilus (la-k) and bifidobacterium longum atcc 15707 were add ...200111286405
generation and analysis of mice lacking the chemokine fractalkine.fractalkine (cx(3)cl1) is the first described chemokine that can exist either as a soluble protein or as a membrane-bound molecule. both forms of fractalkine can mediate adhesion of cells expressing its receptor, cx(3)cr1. this activity, together with its expression on endothelial cells, suggests that fractalkine might mediate adhesion of leukocytes to the endothelium during inflammation. fractalkine is also highly expressed in neurons, and its receptor, cx(3)cr1, is expressed on glial cells. to ...200111287620
a survey of ethnic foods for microbial quality and aflatoxin content.a range of ethnic foods was examined for their microbiological content in relation to total viable counts (tvc) of aerobic bacteria, counts of presumptive coliforms, yeast and mould counts; presence of salmonella spp., listeria monocytogenes, escherichia coli o157:h7 and campylobacter spp.; total enumeration of clostridium perfringens, staphylococcus aureus and bacillus spp.; identification of moulds and the presence of total aflatoxins. samples, which included cereals, nuts, dried fruits, herbs ...200111288910
control of listeria monocytogenes by bacteriocins and monitoring of bacteriocin-producing lactic acid bacteria by colony hybridization in semi-hard raw milk cheese. 200111289262
cd40 signaling converts a minimally immunogenic antigen into a potent vaccine against the intracellular pathogen listeria monocytogenes.conventional vaccination strategies have failed for numerous pathogens, and the development of novel approaches to vaccine development is a major public health priority. killed or subunit vaccines represent an attractive approach due to their safety, but they suffer from low immunogenicity and generally require adjuvants. in this study, the possibility of harnessing cd40 signaling for enhancing the immunogenicity of killed vaccines was investigated. intravenous immunization of c57bl/6 mice with ...200111290793
ethanol consumption and the susceptibility of mice to listeria monocytogenes infection.it is well known that excessive alcohol consumption correlates with increased infectious disease. however, the molecular microbiological and immunological bases for ethanol-induced alterations in host defense are largely unknown.200111290860
antibodies against listerial protein 60 act as an opsonin for phagocytosis of listeria monocytogenes by human dendritic cells.human-monocyte-derived dendritic cells (modc) are very efficient in the uptake of listeria monocytogenes, a gram-positive bacterium which is an important pathogen in humans and animals causing systemic infections with symptoms such as septicemia and meningitis. in this work, we analyzed the influence of blood plasma on the internalization of l. monocytogenes into human modc and compared the uptake of l. monocytogenes with that of salmonella enterica serovar typhimurium and yersinia enterocolitic ...200111292729
protective cytotoxic t lymphocyte responses induced by dna immunization against immunodominant and subdominant epitopes of listeria monocytogenes are noncompetitive.taking advantage of the fact that plasmid dna encoding a single cytotoxic t lymphocyte (ctl) epitope can induce ctls, we examined the influence of t-cell responses to dominant epitopes on those to a subdominant epitope derived from listeria monocytogenes. our data suggest that interaction between t cells against dominant and subdominant epitopes does not operate in the generation of the hierarchy. furthermore, we found that a single dominant epitope is sufficient for the induction of protective ...200111292768
rapd- and acta gene-typing of listeria monocytogenes isolates of human listeriosis, the intestinal contents of cows and beef.seventy-five l. monocytogenes isolates of human listeriosis, the intestinal contents of cows and beef were divided into 5 major clusters, 17 sub-clusters and 28 minor clusters by typing using random amplification of polymorphic dna (rapd). according to their major rapd category, l. monocytogenes isolates serotyped as 1/2b and 4b were distinguished from l. monocytogenes isolates of serovars 1/2a and 1/2c. moreover serovar 4b was distinguished from serovar 1/2b by a difference in the rapd sub-clus ...200111293478
validation of iso method 11290 part 1--detection of listeria monocytogenes in foods.the european and international standard method for the detection of listeria monocytogenes, described in en iso 11290 part 1: 1997 (international organisation for standardisation, geneva) was validated by order of the european commission (standards, measurement and testing fourth framework programme project smt4-ct96-2098). nineteen laboratories in 14 countries in europe participated in a collaborative trial to determine the performance characteristics of the method, which are intended for publi ...200111294351
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