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evaluation of a recombinant listeria monocytogenes expressing an hiv protein that protects mice against viral challenge.vaccine strategies that utilize cell mediated immunity to control infection will be a necessary component of human immunodeficiency virus (hiv) vaccines. in previous studies we have shown that a listeria monocytogenes recombinant expressing hiv-gag elicits strong cd8+ and cd4+ t cell responses against hiv gag in addition to its own secreted proteins. here, we show that lm-gag can protect mice against a viral challenge with a recombinant vaccinia virus expressing gag, in an antigen specific manne ...200111163666
comparison of control of listeria by nitric oxide redox chemistry from murine macrophages and no donors: insights into listeriocidal activity of oxidative and nitrosative stress.the physiological function of nitric oxide (no) in the defense against pathogens is multifaceted. the exact chemistry by which no combats intracellular pathogens such as listeria monocytogenes is yet unresolved. we examined the effects of no exposure, either delivered by no donors or generated in situ within ana-1 murine macrophages, on l. monocytogenes growth. production of no by the two nonoate compounds papa/no (nh2(c3h6)(n[n(o)no]c3h7) and dea/no (na(c2h5)2n[n(o)no]) resulted in l. monocytog ...200111165873
listeria monocytogenes modulates macrophage cytokine responses through stat serine phosphorylation and the induction of suppressor of cytokine signaling 3.macrophage activation as part of natural resistance to infection is caused by stimulation with ifn-gamma and by the invading microorganisms or microbial products. infection of macrophages with the gram-positive bacterium listeria monocytogenes for short periods before activation with ifn-gamma increased the phosphorylation of transcription factor stat1 at s727 and thereby the expression of ifn-gamma-induced genes. by contrast, persistent infection with viable bacteria or treatment with heat-kill ...200111123325
molecular ecology of tetracycline resistance: development and validation of primers for detection of tetracycline resistance genes encoding ribosomal protection proteins.phylogenetic analysis of tetracycline resistance genes encoding the ribosomal protection proteins (rpps) revealed the monophyletic origin of these genes. the most deeply branching class, exemplified by tet and otra, consisted of genes from the antibiotic-producing organisms streptomyces rimosus and streptomyces lividans. with a high degree of confidence, the corresponding genes of the other seven classes (tet m, tet s, tet o, tet w, tet q, tet t, and tetb p) formed phylogenetically distinct sepa ...200111133424
molecular studies on the ecology of listeria monocytogenes in the smoked fish processing industry.we have applied molecular approaches, including pcr-based detection strategies and dna fingerprinting methods, to study the ecology of listeria monocytogenes in food processing environments. a total of 531 samples, including raw fish, fish during the cold-smoking process, finished product, and environmental samples, were collected from three smoked fish processing facilities during five visits to each facility. a total of 95 (17.9%) of the samples tested positive for l. monocytogenes using a com ...200111133446
detection and quantification of the iap gene of listeria monocytogenes and listeria innocua by a new real-time quantitative pcr assay.a real-time quantitative polymerase chain reaction (pcr) assay for direct detection and enumeration of listeria monocytogenes and listeria innocua was developed and applied to artificially contaminated milk samples. the iap gene present in both species was used as a target for amplification of a 175-bp (l. monocytogenes) and a 309-bp (l. innocua) fragment. to ensure that l. monocytogenes and l. innocua are specifically detectable, tests were carried out using 42 l. monocytogenes strains and 33 l ...200111281324
antimicrobial susceptibility of listeria monocytogenes isolated from meningoencephalitis in sheep.the antimicrobial susceptibility to different antimicrobial agents of 41 listeria monocytogenes strains isolated from sheep with meningoencephalitis and from feedstuff was tested by both microdilution and disk diffusion methods. both sets of isolates of l. monocytogenes were susceptible to penicillin g, amoxicillin, cephalothin, erythromycin, vancomycin, rifampicin, gentamicin, kanamycin, trimethoprim, sulfisoxazole, chloramphenicol and ciprofloxacin, but resistant to tetracycline and doxycyclin ...200111282267
sensitization of listeria monocytogenes to low ph, organic acids, and osmotic stress by ethanol.the killing of listeria monocytogenes following exposure to low ph, organic acids, and osmotic stress was enhanced by the addition of 5% (vol/vol) ethanol. at ph 3, for example, the presence of this agent stimulated killing by more than 3 log units in 40 min of exposure. the rate of cell death at ph 3.0 was dependent on the concentration of ethanol. thus, while the presence 10% (vol/vol) ethanol at ph 3.0 stimulated killing by more than 3 log units in just 5 min, addition of 1.25% (vol/vol) etha ...200111282610
enterocin p selectively dissipates the membrane potential of enterococcus faecium t136.enterocin p is a pediocin-like, broad-spectrum bacteriocin which displays a strong inhibitory activity against listeria monocytogenes. the bacteriocin was purified from the culture supernatant of enterococcus faecium p13, and its molecular mechanism of action against the sensitive strain e. faecium t136 was evaluated. although enterocin p caused significant reduction of the membrane potential (deltapsi) and the intracellular atp pool of the indicator organism, the ph gradient (deltaph) component ...200111282622
characterization of listeria monocytogenes strains involved in invasive and noninvasive listeriosis outbreaks by pcr-based fingerprinting techniques.a total of 32 listeria monocytogenes strains (16 from a recent outbreak of invasive listeriosis and 16 from two outbreaks of noninvasive listeriosis, all three occurring in italy) were characterized by pcr-ribotyping, arbitrarily primed pcr (ap-pcr), and the recently developed infrequent-restriction-site pcr (irs-pcr). the discriminatory ability of the techniques, first evaluated on 29 unrelated l. monocytogenes food isolates using simpson's index of diversity, was 0.714 for pcr-ribotyping, 0.69 ...200111282635
detection of phospholipase c in nontuberculous mycobacteria and its possible role in hemolytic activity.phospholipase c plays a key role in the pathogenesis of several bacterial infections, for example, those caused by clostridium perfringens and listeria monocytogenes. previous studies have reported multiple copies of plc genes homologous to pseudomonas aeruginosa plch and plcn genes encoding the hemolytic and nonhemolytic phospholipase c enzymes in the genomes of mycobacterium tuberculosis, m. marinum, m. bovis, and m. ulcerans. in this study we analyzed the possible relationship between phospho ...200111283062
a critical role of t-cell receptor gamma/delta cells in antibacterial protection in mice early in life.although it is generally assumed that t-cell receptor (tcr) gamma/delta cells participate in protection against intracellular microbial pathogens, their impact remains controversial. in our study, young (14-day-old) mice lacking tcrgamma/delta cells were far more susceptible to listeria monocytogenes than wild-type (wt) mice of the same age. the number of interferon gamma (ifn-gamma) producers responsible for antilisterial resistance was significantly higher among natural killer (nk)1(+) tcrgamm ...200111283853
automated simultaneous detection of low levels of listeriae and salmonellae in foods.salmonella spp. and listeria monocytogenes continue to be major pathogens of concern to food processors. however, routine screening of food samples to detect these pathogens is generally labor intensive and costly. automated optical procedures for the detection of salmonellae and listeriae in foods were developed in our laboratory. in the present study we report their adaptation to a simultaneous recovery and detection procedure. milk, shell eggs, fresh and ready-to-eat (rte) meats or raw chicke ...200111246906
effect of different complex carbon sources on growth and bacteriocin synthesis of enterococcus faecium.different criteria are followed in order to select bacteria to be used in probiotic and symbiotic supplements. a new parameter to choose strains could be fermentation by intestinal bacteria of some complex carbohydrates because they are prebiotics and promote the development of beneficial microorganisms in the intestinal environment. an enterococcus faecium strain, isolated from the crop of a free-range chicken, was assayed in order to determine the utilization of commercial sugars and/or crude ...200111246907
characterization and evaluation of some virulence markers of listeria monocytogenes strains isolated from brazilian cheeses using molecular, biochemical and serotyping techniques.a total of 207 l. monocytogenes strains isolated from different types of cheeses commercialized in the city of rio de janeiro, brazil, were serotyped and evaluated for their ability to produce beta-haemolysin and lecithinase and to adsorb congo red dye. of the 207 strains, 59.9, 27.5 and 12.6% belonged to serotypes 1/2a, 1/2b and 4b, respectively. in addition, 175 strains of l. monocytogenes produced lecithinase while strains of the other species did not. some of the non-l. monocytogenes strains ...200111246911
arp2/3 complex and actin dynamics are required for actin-based mitochondrial motility in yeast.the arp2/3 complex is implicated in actin polymerization-driven movement of listeria monocytogenes. here, we find that arp2p and arc15p, two subunits of this complex, show tight, actin-independent association with isolated yeast mitochondria. arp2p colocalizes with mitochondria. consistent with this result, we detect arp2p-dependent formation of actin clouds around mitochondria in intact yeast. cells bearing mutations in arp2 or arc15 genes show decreased velocities of mitochondrial movement, lo ...200111248049
regulating cellular actin assembly.cellular actin assembly is tightly regulated. the study of pathogen motility has led to the identification of several cellular factors that are critical for controlling this process. pathogens such as listeria require ena/vasp and arp2/3 proteins to translate actin polymerization into movement. recent work has extended these observations and uncovered some similarities and surprising differences in the way cells and pathogens utilize the actin cytoskeleton.200111248549
identification of a pest-like motif in listeriolysin o required for phagosomal escape and for virulence in listeria monocytogenes.the hly-encoded listeriolysin o (llo) is a major virulence factor secreted by the intracellular pathogen listeria monocytogenes, which plays a crucial role in the escape of bacteria from the phagosomal compartment. here, we identify a putative pest sequence close to the n-terminus of llo and focus on the role of this motif in the biological activities of llo. two llo variants were constructed: a deletion mutant protein, lacking the 19 residues comprising this sequence (residues 32-50), and a rec ...200111251831
the autolysin ami contributes to the adhesion of listeria monocytogenes to eukaryotic cells via its cell wall anchor.adherence of pathogenic microorganisms to the cell surface is a key event during infection. we have previously reported the characterization of listeria monocytogenes transposon mutants defective in adhesion to eukaryotic cells. one of these mutants had lost the ability to produce ami, a 102 kda autolytic amidase with an n-terminal catalytic domain and a c-terminal cell wall-anchoring domain made up of repeated modules containing the dipeptide gw ('gw modules'). we generated ami null mutations b ...200111251838
thermal inactivation of stationary-phase and acid-adapted escherichia coli o157:h7, salmonella, and listeria monocytogenes in fruit juices.the heat resistance of stationary-phase and acid-adapted escherichia coli o157:h7, salmonella enterica (serotypes typhimurium, enteritidis, gaminara, rubislaw, and hartford), and listeria monocytogenes was evaluated in single-strength apple. orange, and white grape juices adjusted to ph 3.9. the heat resistance increased significantly (p < 0.05) after acid adaptation. salmonella had an overall lower heat resistance than the other pathogens. acid-adapted e. coli o157:h7 presented the highest heat ...200111252473
heat resistance of an outbreak strain of listeria monocytogenes in hot dog batter.the heat resistance of a strain of listeria monocytogenes responsible for a listeriosis outbreak in hot dogs was not higher than the heat resistance of other l. monocytogenes strains when tested in tryptic soy broth and in laboratory-prepared hot dog batter. for the thermal death time experiments, the cells were grown to stationary phase or were starved in phosphate-buffered saline, ph 7, for 6 h at 30 degrees c. starvation increased the heat resistance of l. monocytogenes in broth but not in ho ...200111252474
heat resistance of listeria monocytogenes in vegetables: evaluation of blanching processes.the heat resistance of a listeria monocytogenes composite (serotypes 1/2a, 1/2b, and 4b) was determined in fresh broccoli florets, sweet green peppers, onions, mushrooms, and peas using an end-point procedure in polyester pouches. the heat resistance of l. monocytogenes was higher in peas (d(60 degrees c) = 1.0 min) and mushrooms (d(60 degrees c) = 0.7 min) than in other vegetables tested (d(60 degrees c) in onions = 0.2 min) and was highest when cells were subjected to starvation before the the ...200111252484
heat resistance of listeria monocytogenes.the heat resistance data on listeria monocytogenes in culture media and foods are summarized. most heat resistance data for foods have been obtained in dairy, meat, poultry, and egg products. limited data have been published on seafood, fruits, and vegetables. the methodologies employed have evolved over time; hence data from earlier experiments are not directly comparable to more recent studies. many factors influence the heat resistance of l. monocytogenes. variation exists among different str ...200111252490
survival of listeria monocytogenes during manufacture, ripening and storage of soft lactic cheese made from raw goat milk.soft lactic cheeses were manufactured with raw goat milk inoculated with listeria monocytogenes. the physico-chemical and microbiological characteristics of curds and cheeses were determined after each processing step as well as during ripening and refrigerated storage. the fate of listeria monocytogenes was evaluated by enumeration on palcam agar and by a qualitative detection after a double selective enrichment procedure. the results showed that the physico-chemical and microbiological charact ...200111252508
prevalence of glycopeptide and aminoglycoside resistance in enterococcus and listeria spp. in low microbial load diets of neutropenic hospital patients.low microbial load diets for patients with haematological malignancy were examined for enterococci and listeria using pre-enrichment, enrichment and selective plating. enterococci were highly prevalent and their ecology diverse; 100/211 samples yielded 132 isolates made up of 67 strains distinguishable by pfge. listeria monocytogenes was not found. screening of enterococci for antibiotic resistance showed low level vancomycin resistance (6-12 microg/ml) in six isolates of e. gallinarum and high ...200111252510
use of pfge typing for tracing contamination with listeria monocytogenes in three cold-smoked salmon processing plants.the sites of listeria monocytogenes contamination in three cold-smoked salmon (salmo salar) processing plants were detected by sampling salmon and the plant's environment and equipment at different production stages. of the 141 samples collected from three processing plants, 59 (42%) were contaminated with l. monocytogenes. the rates of contamination varied as to the plant and the sample source. l. monocytogenes isolates from 17 various contaminated seafood products (fresh, frozen and smoked fis ...200111252511
survival of listeria monocytogenes during the manufacture and ripening of turkish white cheese.listeria monocytogenes was enumerated during the manufacture and ripening of turkish white cheese with particular reference to a) pasteurized milk, b) cheese milk after inoculation with l. monocytogenes (0 h), c) after curd formation (2 h), d) curd after pressing (6 h), e) curd after ph was reduced (17 h), f) curd after salting (32 h), and g) cheeses during ripening. cheeses were also examined periodically for total solids, moisture and salt contents, ph values and aerobic plate count. an increa ...200111253643
identification of new genes involved in the virulence of listeria monocytogenes by signature-tagged transposon mutagenesis.listeria monocytogenes is a gram-positive, facultative intracellular pathogen that can cause severe food-born infections in humans and animals. we have adapted signature-tagged transposon mutagenesis to l. monocytogenes to identify new genes involved in virulence in the murine model of infection. we used transposon tn1545 carried on the integrative vector pat113. forty-eight tagged transposons were constructed and used to generate banks of l. monocytogenes mutants. pools of 48 mutants were assem ...200111254558
lack of expansion of major histocompatibility complex class ib-restricted effector cells following recovery from secondary infection with the intracellular pathogen listeria monocytogenes.sublethal infection of balb/c mice with the intracellular bacterial pathogen listeria monocytogenes leads to the development of antilisterial immunity with concurrent stimulation of major histocompatibility complex (mhc) class ia- and ib-restricted cd8+ effector t cells. secondary l. monocytogenes infection is followed by an accelerated increase in the number of listeria-specific cd8+ cells and rapid clearance of the bacterium from the murine host. recovery from secondary infection is associated ...200111254585
secretion of listeriolysin by brucella suis inhibits its intramacrophagic replication.the introduction into brucella suis 1330 of a plasmid allowing the heterologous expression of a hybrid cytolysin containing listeriolysin from listeria monocytogenes, and its export via the escherichia coli hemolysin secretion pathway, resulted in secretion of active listeriolysin monitored by erythrocyte lysis. in contrast to observations with the nonhemolytic control strain, the phagosomes of infected human monocytes containing the hemolytic b. suis were partially disrupted, and this strain fa ...200111254648
bactericidal activities of milk lipids.the bactericidal capacity of digestion products of bovine milk triglycerides and membrane lipids was tested in vitro using escherichia coli o157:h7, salmonella enteritidis, campylobacter jejuni, listeria monocytogenes, and clostridium perfringens. c10:0 and c12:0 fatty acids and digestion products of sphingolipids appeared to be effective bactericidal agents, whereas digestion products of phosphoglycerides were moderately bactericidal. thus, milk fat sphingolipids and triglycerides, particularly ...200111257052
blocking the receptor for interleukin 10 protects mice from lethal listeriosis.high doses of listeria monocytogenes overcome the ability of a normal mouse to control the infection, due to massive bacterial replication. treatment with an anti-interleukin 10 (il-10) receptor monoclonal antibody prevented the fatal course of infection with high doses of bacteria. this work shows that blocking the receptor for il-10 may have useful therapeutic applications.200111257056
gram-positive and gram-negative bacteria as carrier systems for dna vaccines.vaccination by intradermal or intramuscular injection of eukaryotic antigen expression vectors (so-called dna vaccines) elicits strong cellular and humoral immune responses. a novel approach employs attenuated mutant strains of gram-positive and gram-negative intracellular bacteria as carriers for the delivery of dna vaccines. this strategy allows the administration of the dna vaccines via mucosal surfaces and a direct delivery of the plasmid dna to professional antigen presenting cells (apc), s ...200111257384
recombinant attenuated bacteria for the delivery of subunit vaccines.using attenuated intracellular bacteria as carriers, we have developed two different approaches for the delivery of subunit vaccines encoding heterologous antigens. the first system is based on the direct secretion of the heterologous antigens in gram-negative bacteria via the hemolysin secretion system of escherichia coli into either phagosome or cytosol of infected cells. the second approach is based on the transport of eukaryotic antigen expression vectors by intracellular bacteria like liste ...200111257401
interferon-gamma listericidal action is mediated by novel rab5a functions at the phagosomal environment.control and clearance of listeria monocytogenes infection is an interferon-gamma-dependent process. the listericidal mechanism of action involves activation of nadph oxidase and inducible nitric-oxide synthase to produce reactive oxygen and nitrogen intermediate radicals, respectively. recently, we have described in a nonpathogenic model of l. monocytogenes (hemolysin negative mutant strain) that the interferon-gamma-inducible gtpase rab5a contributed to listeria destruction in resting macrophag ...200111262414
[listeria arthritis in chronic polyarthritis during low dose prednisolone and methotrexate therapy. case report and review of the literature].we report about a patient with polyarticular rheumatoid arthritis taking methotrexat and 5 mg prednisolone who developed in the course of a ra flare a septic arthritis in the right shoulder. listeria monocytogenes could be identified as the causative bacteria. clinically, the listeria-induced septic arthritis could not be differentiated from rheumatoid arthritis; fever was not present. the synovial analysis showed a granulocytic effusion with 19,000 cells/ml; there was no microbiological growth ...200111263013
listing listeria's health risks. 200111263089
preferential localization of effector memory cells in nonlymphoid tissue.many intracellular pathogens infect a broad range of host tissues, but the importance of t cells for immunity in these sites is unclear because most of our understanding of antimicrobial t cell responses comes from analyses of lymphoid tissue. here, we show that in response to viral or bacterial infection, antigen-specific cd8 t cells migrated to nonlymphoid tissues and were present as long-lived memory cells. strikingly, cd8 memory t cells isolated from nonlymphoid tissues exhibited effector le ...200111264538
[interaction between membrane-damaging toxin of listeria monocytogenes and host immune system]. 200111268660
dietitians can prevent listeriosis. 200111269602
dietary supplementation with conjugated linoleic acid does not alter the resistance of mice to listeria monocytogenes infection.conjugated linoleic acid (cla) has been used experimentally as a dietary supplement to increase lean body weight and to modulate inflammation in a variety of animal species. in addition, human use of dietary cla as a supplement to regulate body fat has received both scientific and public attention. no reports have been published regarding the effects of dietary cla on antimicrobial resistance. in this study, we provide evidence that feeding cla for up to 4 wk does not alter host defense against ...200111269693
extent of microbial contamination in united states pork retail products.to determine the extent of microbiological contamination of u.s. pork, 384 samples of retail pork were collected from 24 stores in six cities, including (i) whole-muscle, store-packaged pork; (ii) fresh, store-packaged ground pork and/or pork sausage; (iii) prepackaged ground pork and/or pork sausage; and (iv) whole-muscle, enhanced (injected or marinated; 60% store-packaged, 40% prepackaged) pork. additional samples (n = 120) of freshly ground pork and/or pork sausage were collected from two ho ...200111271763
comparison of different enrichment broths and background flora for detection of heat-injured listeria monocytogenes in whole milk.various primary enrichment broths, including university of vermont medium (uvm), listeria enrichment broth (leb), modified leb, and aerobic and anaerobic l-palcamy, were compared with aerobic and anaerobic pennsylvania state university (psu) broths for the detection of severely heat-injured (62.8 degrees c for 5, 10, or 15 min; no colony appearance after heat injury on aerobic trypticase soy agar containing 0.6% yeast extract and modified oxford medium) listeria monocytogenes scott a. anaerobic ...200111198438
strain-related differences of nonspecific respiratory defense mechanisms in rats using a pulmonary infectivity model.a number of animal studies have assessed pulmonary host defense mechanisms by inoculating the lungs with the bacterial agent, listeria monocytogenes. most studies use only a single strain of the animal to be tested; however, strain-related differences in responsiveness to pulmonary toxicants have been well documented. it was the goal of this current investigation to measure the pulmonary defense responses of two different strains of rats in a lung infectivity model. fischer 344 (f344) and spragu ...200111153062
the use of host cell machinery in the pathogenesis of listeria monocytogenes.the bacterial pathogen, listeria monocytogenes, exploits the host cell's machinery, enabling the pathogen to enter into cells and spread from cell to cell. three bacterial surface proteins are crucial for these processes: internalin and inlb, which mediate entry into cells, and acta, which induces actin polymerisation at one pole of the bacterium and promotes intracellular and intercellular motility. recent studies have identified several of the cellular factors involved in the entry process and ...200111154924
bystander activation of cd8+ t cells contributes to the rapid production of ifn-gamma in response to bacterial pathogens.the bacterium burkholderia pseudomallei causes a life-threatening disease called melioidosis. in vivo experiments in mice have identified that a rapid ifn-gamma response is essential for host survival. to identify the cellular sources of ifn-gamma, spleen cells from uninfected mice were stimulated with b. pseudomallei in vitro and assayed by elisa and flow cytometry. costaining for intracellular ifn-gamma vs cell surface markers demonstrated that nk cells and, more surprisingly, cd8(+) t cells w ...200111145690
variable immunodominance hierarchies for h2-m3-restricted n-formyl peptides following bacterial infection.h2-m3-restricted presentation of n-formyl methionine (f-met) peptides to cd8(+) t cells provides a mechanism for selective recognition of bacterial infection. in this report we demonstrate that listeria monocytogenes infection induces distinct cd8(+) t cell populations specific for each of the known listeria-derived formyl methionine peptides presented by m3. the sum h2-m3-restricted, listeria-specific t cell response constitutes a major fraction of the total cd8(+) t cell response to primary in ...200111145694
factors influencing resuscitation and growth of heat injured listeria monocytogenes 13-249 in sous vide cooked beef.the growth of listeria monocytogenes 13-249 in vacuum-packed, minced beef was investigated as a function of degree of heat injury (including no injury i.e. uncooked beef), growth phase (logarithmic and late stationary phase), ph (5.6 and 6.2), and storage temperature (3, 10 and 20 degrees c) during a storage period of 30 days. late logarithmic and late stationary phase cultures of l. monocytogenes 13-249 showed similar growth in refrigerated, vacuum-packed, raw minced beef with a high ph (6.2). ...200111205945
high incidence of listeria monocytogenes in european red smear cheese.the incidence of listeria and listeria monocytogenes in european red smear cheese was determined in order to assess whether the lack of recent outbreaks of listeriosis associated with cheese is due to improved hygenic conditions in the dairies. out of european red-smear cheese samples of various types, 15.8% contained organisms of the genus listeria, 6.4% of the samples were contaminated with l. monocytogenes, 10.6% with l. innocua, and 1.2% with l. seeligeri. six cheese samples contained two or ...200111205958
organ-specific regulation of the cd8 t cell response to listeria monocytogenes infection.the intestinal mucosal cd8 t cell response to infection with listeria monocytogenes was measured using mhc class i tetramers and was compared with the response in peripheral blood, secondary lymphoid tissue, and liver. to assess the vaccination potential of listeria and to analyze responses in c57bl/6 mouse strains, a recombinant listeria expressing ova (rlm-ova) was generated. the response peaked at 9 days postinfection with a much larger fraction of the intestinal mucosa and liver cd8 t cell p ...200111207297
pregnant women get no bologna--or shark or brie. 200111211338
ozone-induced modulation of cell-mediated immune responses in the lungs.most pulmonary immunotoxicology studies of ambient pollutants have been broadly designed to discern if overall humoral or cell-mediated immunity (cmi) was altered; few have assessed effects on particular aspects of immune function. we hypothesized that effects from ozone (o3) exposure on pulmonary cmi are linked in part to changes in local immune cell capacities to form and/or to interact with immunoregulatory cytokines. rats exposed to 0.1 or 0.3 ppm o3 4 h/day 5 days/week, for 1 or 3 weeks wer ...200111222083
systemic immunity and mucosal immunity are induced against human immunodeficiency virus gag protein in mice by a new hyperattenuated strain of listeria monocytogenes.vaccines designed to control chronic infections by intracellular agents such as human immunodeficiency virus type 1 (hiv-1) require the induction of cell-mediated immune responses to rid the host of pathogen-infected cells. listeria monocytogenes has characteristics that make it an attractive vaccine vector for use against such infections. here we show that parenteral immunization with a new highly attenuated strain of this organism provided complete protection against systemic and mucosal chall ...200111222702
elicitation of predictable immune responses by using live bacterial vectors.there is an increasing need for novel vaccines able to stimulate efficient and long-lasting responses, which have also low production costs. to confer protective immunity following vaccination, the adequate type of response should be elicited. vaccines based on attenuated bacterial carriers have contained production and delivery costs, and are able to stimulate more potent immune responses than non-replicating formulations. the improved knowledge on carrier physiology and host response, the avai ...200111222981
microbiological quality of fresh leafy vegetables, salad components and ready-to-eat salads: an evidence of inhibition of listeria monocytogenes in tomatoes.a total of 116 samples of 11 different fresh vegetables from a local market generally consumed in raw form as well as 12 samples of ready-to-eat green salads procured from three grade 1 and 2 restaurants in mumbai, india were examined for overall microbial quality in terms of bacterial, mold and coliform levels and incidence of pathogens such as listeria and yersinia. standard procedures and media were used for isolation and identification studies. thoroughly washed samples of 26 leafy vegetable ...200111225173
diversity in phagocytic signalling. 200111228148
ultrastructural localization of succinate dehydrogenase in some bacteria, after treatment with lubrol w1.the localization of succinate dehydrogenase in some gram-negative and gram-positive bacteria (salmonella typhimurium, pseudomonas pseudomallei, pseudomonas aeruginosa and listeria monocytogenes) treated with the surface membrane active agent, lubrol w1, was studied by a cytochemical method combined with electron microscopy.200111229657
from the centers for disease control and prevention. multistate outbreak of listeriosis--united states, 2000. 200111236753
flt3 ligand pretreatment promotes protective immunity to listeria monocytogenes.flt3 ligand (flt3l) plays a critical role in the proliferation, differentiation and survival of haematopoietic progenitor cells. its potential use in a clinical setting has been suggested. here, we report that mice administered flt3l displayed a nine-fold increase in size of their hepatic non-parenchymal cell population and an approximate 365-fold increase in number of mature dendritic cells within their livers. such mice exhibited an elevated resistance to secondary infections with listeria mon ...200111237427
the tumor recall response of antitumor immunity primed by a live, recombinant listeria monocytogenes vaccine comprises multiple effector mechanisms.listeria monocytogenes, a facultative intracellular bacterium, can induce a potent antitumor immune response if engineered to express a model tumor antigen also expressed by the tumor cells. the effectiveness of this approach is dependent on l. monocytogenes-induced tumor-specific cd4(+) and cd8(+) t-cells. cd8(+) t-cells may mediate tumor eradication largely through direct ctl activity, but the role of cd4(+) t-cells and other cells of the immune system is less clear. here we investigate their ...200111237558
bactericidal properties of group iia and group v phospholipases a2.group v phospholipase a(2) (pla(2)) is a recently characterized 14-kda secretory pla(2) of mammalian heart and macrophage-derived cells. group iia pla(2), which is structurally close to group v pla(2), has been shown to kill gram-positive bacteria in vitro and to prevent symptoms of gram-positive infection in vivo. we studied the antibacterial properties of fully active recombinant rat group iia and v pla(2)s. both group iia and v pla(2)s were highly bactericidal against gram-positive bacteria, ...200111238650
intestinal and splenic t cell responses to enteric listeria monocytogenes infection: distinct repertoires of responding cd8 t lymphocytes.listeria monocytogenes is an intracellular bacterium that causes systemic infections after traversing the intestinal mucosa. clearance of infection and long term protective immunity are mediated by l. monocytogenes-specific cd8 t lymphocytes. in this report, we characterize the murine cd8 t cell response in the lamina propria and intestinal epithelium after enteric l. monocytogenes infection. we find that the frequency of mhc class ia-restricted, l. monocytogenes-specific t cells is approximatel ...200111238655
met, the hgf-sf receptor: another receptor for listeria monocytogenes.the bacterium listeria monocytogenes invades a variety of cells in vitro and in vivo. two proteins are crucial in this process: internalin, which interacts with e-cadherin, and inlb. the first identified ligand for inlb was gc1qr, which has no cytoplasmic domain. the newly discovered inlb receptor, met, fits with the known inlb-induced signals.200111239771
chemical sympathectomy increases the innate immune response and decreases the specific immune response in the spleen to infection with listeria monocytogenes.many investigators have shown that ablation of the sympathetic nervous system (sns) with 6-hydroxydopamine (6-ohda) can alter cell-mediated and humoral immune responses to antigenic challenge. fewer studies have examined 6-ohda-induced changes in natural immunity. in this study, we have examined the effect of chemical sympathectomy on the nonspecific and specific phases of the response to infection with listeria monocytogenes. sympathectomy decreased splenic bacterial loads 3 and 5 days post-inf ...200111240011
memory phenotype cd8(+) t cells in il-15 transgenic mice are involved in early protection against a primary infection with listeria monocytogenes.we recently constructed il-15 transgenic (tg) mice using cdna encoding a secretable isoform of the il-15 precursor protein under the control of an mhc class i promoter. the il-15 tg mice exhibited resistance against a primary infection with listeria monocytogenes. the numbers of memory cd8(+) t cells were markedly increased in the il-15 tg mice following listeria infection accompanied by sustained il-15 production. the increased cd44(+)cd8(+) t cells in the infected il-15 tg mice were not specia ...200111241280
multigenic control of listeria monocytogenes susceptibility in mice.we have used a novel quantitative trait locus model to study the genetics of survival of f2 progeny of susceptible balb/cbyj and resistant c57bl/6byj mice that have been infected with listeria monocytogenes. this allowed us to map modifiers of l. monocytogenes susceptibility to chromosomes 5 and 13.200111242105
[finding the cause of death in intrauterine death--which examination should be done?].the incidence of antepartum fetal death after 22 weeks of gestation is about 0.4% in oslo, norway. screening routines will decide how many cases will remain unexplained. one quarter are diagnosed as sudden intrauterine unexplained death (siud). precise knowledge of the cause of death is needed as a basis for counselling, prevention and treatment.200111242876
bacterial carriers and virus-like-particles as antigen delivery devices: role of dendritic cells in antigen presentation.replicating attenuated strains of intracellular bacteria like salmonella typhimurium, listeria monocytogenes or mycobacterium bovis bacille calmette guérin (bcg), and non-replicating virus-like-particles (vlp) consisting, for instance, of the vp1-surface component of polyoma virus offer great potential as heterologous carriers delivering foreign protein antigens for immune recognition. moreover, attenuated s. typhimurium and l. monocytogenes strains hold also great promise as delivery vehicles f ...200112455402
[a case of untreated systemic lupus erythematosus presenting with listerial meningitis].a fourty-year-old woman suffered from meningitis and sepsis of listeria monocytogenes, after presenting with several early symptoms from systemic lupus erythematosus (sle). listeriosis often causes central nervous system infection with relatively high mortality rate. this infection commonly affects patients with predisposing factor, such as immunosuppression. according to the previous reports, all of the previous reports, all of listeriosis with sle received immunosuppressive therapy. to the bes ...200111968742
[listeria monocytogenes induces thymocyte apoptosis in mice].the murine thymocyte apoptosis induced by listeria monocytogenes(lm) was detected with morphology, fcm, and dna electrophoresis. the results were that lm elicited typical morphological changes of thymocyte apoptosis; the typical apoptosis peak was displayed with fcm, and typical "ladder pattern" with agarose gel electrophoresis. the apoptotic cells were found at 8 h after the mice had infected lm and reached climax at 48 h. the thymus weight significantly reduced at 16 h, and reached the lowest ...200112536719
evaluation of immunotoxicity induced by single or concurrent exposure to n,n-diethyl-m-toluamide (deet), pyridostigmine bromide (pyr), and jp-8 jet fuel.approximately 5,000 to 80,000 of the us service personnel involved in the persian gulf war have complained of a variety of nonspecific symptoms since their return in 1991. these symptoms have been collectively labeled gulf war illness and include muscle fatigue, general malaise, myalgia, impaired cognition, ataxia, headaches, fever, joint pain, skin rash, gastrointestinal disturbances, sleep disturbances, and respiratory difficulties. exposures of military and service personnel were diverse and ...200112539864
involvement of listeria monocytogenes in the abortive disease.listeria monocytogenes, an intracellular facultative germ that causes the invasion, sometimes fatal, in susceptible hosts is a food borne pathogen with ubiquitary spread that has generated a public health problem for such risk groups as: pregnant women, foetuses, new borns. 504 women with abortive disease were serologically investigated in 1999 for serotype 1a circulating in romania. the most affected age group proved to be that in the range of 20-30 yrs: 378 (75%) cases. 107 (21.23%) female pat ...200112561675
occurrence of listeria spp. in captive antelope herds and their environment.two juvenile scimitar-horned oryx (oryx dammah) at the wild animal park planckendael died from acute septicemia caused by listeria monocytogenes serovar 4b. subsequently, listeria spp. were isolated from the feces, food, and environment of seven antelope species and examined using a two-stage enrichment procedure in fraser broth, followed by isolation on palcam agar. a total of 40/170 samples (23.5%) was positive for listeria spp. no organisms were cultured in 83/170 samples (48.8%), and 47 samp ...200112785709
[hematometra & listeria monocytogenes].the hematometra is a nosological entity that may not always be attributed to an embryonic defect of the paramesonefros; cervical-vaginal infections such as etiological possibilities due to listeria monocytogenes (lm), cervix malignant neoplasias, iatrogenias due to endometrial ablation with lasser, traumatic bloody uterine curetage and because of cervical cryocoagulation or electrocoagulation are also mentioned. the case to be reported is from a woman in reproductive stage, who is 32 years old, ...200115326808
characterization of bacteriocin n15 produced by enterococcus faecium n15 and cloning of the related genes.enterococcus faecium n15 was isolated from nuka (japanese rice-bran paste), which is utilized as starter in the fermenting of vegetables, and was found to produce a bacteriocin that exhibited a broad spectrum of activity, including activity against listeria monocytogenes and bacillus circulans jcm2504. the bacteriocin was sensitive to proteases (alpha-chymotrypsin, proteinase k, trypsin, and pepsin) and alpha-amylase, but it was resistant to lipase. the bacteriocin was resistant to heat treatmen ...200116233010
is listeria monocytogenes an important pathogen for prosthetic joints?listeria monocytogenes usually causes meningitis or bacteremia, often in immunocompromised adults, pregnant women, or infants. we report a case of septic arthritis caused by l. monocytogenes in a patient with seronegative rheumatoid arthritis (ra) whose hip replacement was infected. she subsequently died, probably secondary to an adult respiratory distress syndrome, a rare complication of listerial infection. we also reviewed all 18 previously reported cases of septic arthritis caused by l. mono ...200117039086
antagonistic effect on listeria monocytogenes and l. innocua of a bacteriocin-like metabolite produced by lactic acid bacteria isolated from sucuk.two lactobacilli and four pediococci strains producing bacteriocin-like metabolities isolated from sucuk were tested with agar spot tests and well diffusion assays for their inhibitory activity against 16 listeria strains, also isolated from sucuk. the production of organic acids and hydrogen peroxide limited, l. sake lb 706 (used as a bacteriocin producer strain) and the isolated lactic acid bacteria (lab) showed inhibitory activity against all of the listeria strains, while l. sake lb 706-a (u ...200122062969
occurrence of escherichia coli o157:h7, listeria monocytogenes, salmonella and campylobacter spp. on beef carcasses in northern ireland.a survey of beef carcasses was conducted in all 10 european community approved abattoirs in northern ireland to determine the incidence of escherichia coli o157:h7. analyses were based on excised samples of neck meat taken less than 48 h post-kill. overall, 780 carcasses were sampled and all were negative for e. coli o157:h7. a sub-set of samples was analysed for the presence of listeria monocytogenes (n=200), salmonella (n=200) and campylobacter spp.(n=100). l. monocytogenes was not detected bu ...200122062423
a promoter probe plasmid based on green fluorescent protein : a strategy for studying meningococcal gene expression.many bacterial genes are regulated in an environment-responsive fashion, and from the perspective of a pathogen, the host represents just another environment. many genes that contribute to virulence are differentially expressed in response to host environments that they encounter during colonization and invasion (1). recognition of this has led to the development of selection or reporter systems that utilize the increased activity of promoters during growth in vivo to identify genes that are sel ...200121337172
production of mortadella: behavior of listeria monocytogenes during processing and storage conditions.the presence of listeria monocytogenes in ready-to-eat meat products is cause of concern to the food industry as well as to health authorities. studies were conducted to evaluate the presence of l. monocytogenes in mortadellas acquired at retail stores and to evaluate the fate of two levels of a l. monocytogenes pool spiked in two different formulations of the product, cooked under commercial conditions and stored at refrigeration (7°c) and room temperature (25°c). among the samples collected at ...200122061161
recombinant single chain antibodies in bioelectrochemical sensors.recombinant antibodies provide an emerging strategy in the development of new immunosensors. in particular, single chain antibodies (scfvs) can be isolated and expressed in bacterial systems that also allow their in vitro manipulation at the gene level. in this work, we present for the first time results of single-chain phage displayed antibodies combined with amperometric detection and its application as an immunosensor. the scfv is immobilized on a carbon electrode and used to capture and quan ...200118968440
choosing and preparing antigen-presenting cells.the first issue in many antigen-processing experiments is to choose and obtain appropriate antigen-presenting cells (apcs). macrophages have characteristics that dictate their use in certain antigen-processing experiments, so this unit describes preparation of activated macrophages, which involves eliciting peritoneal macrophages from mice by infection with listeria monocytogenes. this method is often preferred because the resulting macrophages are more consistently activated to a high degree, b ...200118432740
animal model for infection with listeria monocytogenes.this unit describes methods for infecting mice with l. monocytogenes. optimal media for growth and methods to maintain bacterial virulence by passage through mice are included. methods for determining the severity of splenic and hepatic infection are detailed, with strategies for distinguishing innate from specific immune responses following l. monocytogenes infection. this infection induces mhc class i-restricted cd8(+) cytolytic t lymphocytes that clear infection and provide long-term immunity ...200118432760
plasmid-mediated streptomycin resistance of listeria monocytogenes.a strain of streptomycin-resistant listeria monocytogenes lm35 isolated from imported frozen beef was examined in this study. in conjugation studies, the l. monocytogenes lm35 strain harbouring two plasmids of 54, 3.0, 2.8 and 2.7 kilobase was used as the donor and streptomycin-sensitive and plasmidless l. monocytogenes lm65 and lm100 strains as the recipients. streptomycin resistance was transferred to l. monocytogenes lm65 and lm100 strains at frequencies of 3.3 × 10(-8) and 1.2 × 10(-9) per i ...200122973158
[inflammatory bowel disease--do microorganisms play a role?].this review focuses on the potential pathogenic role of microorganisms in relation to inflammatory bowel diseases, i.e. crohn's disease and ulcerative colitis. pathogenic microorganism such as mycobacterium paratuberculosis, measles and mumps viruses, epstein-barr virus, and listeria monocytogenes are discussed, as well as involvement of the normal intestinal flora. furthermore, the influence of microorganisms in experimental animal colitis models is discussed. the available results are inconclu ...200212553118
adult community acquired bacterial meningitis in a singaporean teaching hospital. a seven-year overview (1993-2000).the objective of this study is to describe the bacteriological, clinical and laboratory features of community acquired bacterial meningitis in adults admitted to a singapore tertiary-care hospital.200212693768
[isolation and identification of listeria monocytogenes and listeria spp. in dry sausages obtained in markets in the city of la plata, argentina].a total of 60 samples of dry sausages were analyzed (50 of "salami" and 10 of "chorizo" "candelario" type) obtained at random in markets authorized for their commercialization, for the purpose of evidencing the presence of bacteria of the genus listeria (listeria monocytogenes and listeria spp.). the results obtained in salami were the following: 10 (20%) isolates of listeria spp., were characterized: 1 (2%) strain as l. monocytogenes type 1, 7 (14%) strains as l. innocua, 2 (4%) strains as l. w ...200212600006
[studies on the effect of combined treatment of irradiation with vacuum packaging on ready-to-eat meat products contaminated with listeria monocytogenes and spoilage bacteria].altogether one hundred and fifty samples of beijing roast duck, roast chicken and cooked meat products inoculated with approximately 1.5 x 10(3)-2.3 x 10(3) cfu/g l. monocytogenes are packed under vacuum and are irradiated with 60co radiation at doses of 1.0, 2.0, 2.5 and 3 kgy. the results showed that l. monocytogenes in samples can be eliminated by a dose of 2.5 kgy. the resistance of the model strain 54004 to irradiation is stranger than three isolates (x20, g4 and g2). in addition, the spoil ...200212600048
[an elderly case with listeria monocytogenes sepsis and pulmonary non-tuberculous mycobacterial infection].a 88-year-old woman, who had lived in a nursing home, was admitted to our hospital because of the suspicion of pulmonary tuberculosis. she had a cough, fever and diarrhea on admission. she suffered from sepsis because listeria monocytogenes was isolated from only the blood culture twice. we immediately administered imipenem/cilastatin to her on admission. she simultaneously had pulmonary non-tuberculous mycobacterial infection because the chest roentgenogram showed a cavity in the right upper lu ...200212607349
effects of gamma ray and electron-beam irradiations on survival of anaerobic and facultatively anaerobic bacteria.an extension of the approval for food irradiation is desired due to the increase in the incidence of food poisoning in the world. one anaerobic (clostridium perfringens) and four facultatively anaerobic (bacillus cereus, escherichia coli o157:h7, listeria monocytogenes, and salmonella enteritidis) bacteria irradiated with gamma ray or electron beam (e-beam) were tested in terms of survival on agar under packaging atmosphere. using pouch pack, effects of two irradiations on survival of anaerobic ...200212638185
intra-abdominal abscess caused by listeria monocytogenes in a patient with acquired hemolytic anemia and thrombocytopenia.we report a case of an intra-abdominal abscess caused by listeria monocytogenes in a postoperative patient with evans syndrome (acquired hemolytic anemia and thrombocytopenia). focal infections with l. monocytogenes are uncommon but have been reported in immunocompromised patients. a few cases of liver abscess in diabetic patients have also been reported. the present case is significant because of the paucity of previously described focal intra-abdominal infections caused by l. monocytogenes, pa ...200212540008
fda and fsis issue listeria health advisory. 200212523285
cpg-odn-induced inflammation is sufficient to cause t-cell-mediated autoaggression against hepatocytes.autoimmune diseases are often associated with microbial infections. molecular mimicry between microbial antigens and self-epitopes has been suggested as a mechanism for breaking self-tolerance and induction of autoimmunity. since infections also cause inflammatory responses we explored the role of local inflammation in organ-specific autoimmunity. for this purpose, transgenic mice were used expressing the mhc class i molecule kb exclusively on hepatocytes. these mice exhibit kb-specific toleranc ...200212516551
structure of internalin, a major invasion protein of listeria monocytogenes, in complex with its human receptor e-cadherin.listeria monocytogenes, a food-borne bacterial pathogen, enters mammalian cells by inducing its own phagocytosis. the listerial protein internalin (inla) mediates bacterial adhesion and invasion of epithelial cells in the human intestine through specific interaction with its host cell receptor e-cadherin. we present the crystal structures of the functional domain of inla alone and in a complex with the extracellular, n-terminal domain of human e-cadherin (hec1). the leucine rich repeat (lrr) dom ...200212526809
effect of reuterin produced by lactobacillus reuteri on the surface of sausages to inhibit the growth of listeria monocytogenes and salmonella spp.reuterin is a bacteriocin produced by some strains of lactobacillus reuteri. the strain used in this study was isolated from raw milk from a dairy farm nearby ankara. beef sausage is a long years produced bratwurst style meat product in turkey, as well as in some other countries in the mediterranean region. sausages are produced by raw meat; sometimes lactic starter cultures are added or spontaneous fermentation is employed. the production and storage conditions of the product promotes the growt ...200212577589
inhibition of listeria monocytogenes lmg10470 by plantaricin ug1 in vitro and in beef meat.the inhibition of listeria monocytogenes lmg 10470 occurred due to plantaricin ug1, but not to lactic acid produced by lactobacillus plantarum ug1 or its negatie variant (bac). partially purified plantaricin ug1 had a higher antilisterial activity in vitro and in meat than lactobacillus plantarum ug1 culture. plantaricin ug1 activity was higher in brain heart infusion (bhi) broth than in minced meat. the inhibitory effect of plantaricin ug1 against l. monocytogenes lmg10470 was dependent on its ...200212577590
bacterial contamination of cucumber fruit through adhesion.in this study, the adhesion of bacteria to fresh cucumber surfaces in aqueous suspension was shown to be dependent on time of incubation, inoculum species and concentration, and temperature. the adhesion of bacteria to the fruit in wash water was less extensive at lower temperatures and shorter exposure times. various species of bacteria were adsorbed to cucumber surfaces in the following relative order: salmonella typhimurium > staphylococcus aureus > lactobacillus plantarum > listeria monocyto ...200212495005
incidence and susceptibility to antimicrobial agents of listeria spp. and listeria monocytogenes isolated from poultry carcasses in porto, portugal.the occurrence of listeria spp. and listeria monocytogenes in 63 samples of portuguese poultry carcasses obtained from two local butcher shops and one canteen in the city of porto, portugal, and the susceptibility of these bacteria to antimicrobial agents allowed for use in human or animal therapeutics were evaluated. all poultry samples were contaminated with listeria spp., and l. monocytogenes was isolated from 41% (26 of 63) of the samples. other listeria species, including l. innocua, l. wel ...200212495006
microbial antagonists of foodborne pathogens on fresh, minimally processed vegetables.on many types of raw or minimally processed foods, the bacterial microbiota is often composed of mixed species. the activities of one bacterial species may influence the growth and activities of others that are present. the objective of this project was to evaluate the microbial composition of fresh and minimally processed vegetables to determine if naturally occurring bacteria on produce are competitive with or antagonistic to potentially encountered pathogens. naturally occurring bacteria were ...200212495009
death of salmonella, escherichia coli o157:h7, and listeria monocytogenes in garlic butter as affected by storage temperature.garlic is known to have antimicrobial activity against several spoilage and pathogenic bacteria. however, the fate of salmonella, escherichia coli o157:h7, and listeria monocytogenes in garlic butter has not been reported. this study was undertaken to determine the viability of these organisms in garlic butter as affected by the type of raw minced garlic added to the butter, storage temperature, and storage time. unsalted butter at 40 degrees c was combined with raw minced jumbo, elephant, or sm ...200212495019
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