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identification and characterization of a novel prfa-regulated gene in listeria monocytogenes whose product, irpa, is highly homologous to internalin proteins, which contain leucine-rich repeats.the expression of all virulence factors in listeria monocytogenes characterized to date is controlled by the virulence regulator protein, prfa. to identify further prfa-regulated proteins, we examined supernatants of l. monocytogenes egd harboring additional copies of the prfa regulator for the presence of novel proteins. this led to the identification and biochemical purification of a hitherto uncharacterized prfa-dependent 30-kda protein (a. lingnau, t. chakraborty, k. niebuhr, e. domann, and ...19978975898
[obstructive renal insufficiency caused by amoxicillin crystalluria].a 76-year-old woman was admitted to the icu for a meningitis with rhombencephalitis due to listeria monocytogenes. the treatment included amoxicillin (250 mg.kg-1.day-1) and gentamicin (3 mg.kg-1.day-1 over 6 days). neurological outcome was favourable. however at the 14th day, an acute renal failure occurred, following macroscopic haematuria and milkiness urine. ct scan and sonography confirmed the diagnosis of obstructive renal failure with bilateral ureteral obstruction. crystalluria caused by ...19979750621
report of 24 cases of listeria monocytogenes infection at the university of miami medical center.to examine the epidemiological spectrum of human listeriosis at a large municipal hospital in miami, we reviewed the cases of listeria monocytogenes infection seen at the university of miami medical center over a nine-year period (1986-94). twenty-four patients (13 adults, 11 neonates) with bacteriologically proven listeria monocytogenes infections were identified. the annual rate of listeriosis for the entire period 1986-1994 was 0.042 cases/1,000 hospital admissions. the rates of listeriosis d ...19979707990
nonhemolytic strains of listeria monocytogenes detected in milk products using vidas immunoassay kit.in december 1995 detection of listeria monocytogenes sv 1/2a in milk products that were routinely sampled for investigation at the austrian federal food inspection laboratory (vienna) led the food manufacturer in question to withdraw his product from the market. while one of seven listeria strains isolated from this food product using "vidas l. monocytogenes kit" was undoubtedly l. monocyotogenes, six strains were nonhemolytic. in classical bacteriology haemolysin is used as an important phenoty ...19979636989
evidence that the same gamma delta t cells respond during infection-induced and autoimmune inflammation.inflammatory responses are induced in both testes of a mouse following injection of listeria monocytogenes into one testis. although the uninjected testis contains no detectable bacteria, it undergoes an autoimmune attack. normally, the testis lacks lymphocytes, but in the infected and autoimmune state, both gamma delta and alpha beta t cells are found as infiltrates. here, we have examined the repertoire of the infiltrating gamma delta t cells, using two different methods, and found a high freq ...19979550374
a model describing the relationship between lag time and mild temperature increase duration.when a bacterial population undergoes an unfavourable increase in temperature for a given duration, called stress duration, a death phase followed by a lag and a growth phase are observed. the lag phase is actually of great interest in regard to foodstuff safety in choosing a suitable protocol for the detection of microorganisms which have undergone a mild heat treatment. the extension of lag time with the severity of the increase in temperature has been highlighted by previous papers. our exper ...19979506281
inhibition of listeria monocytogenes on cold-smoked salmon by nisin and carbon dioxide atmosphere.the bacteriostatic and bacteriocidal effect of nisin in combination with carbon dioxide, nacl and low temperature on the survival of listeria monocytogenes was investigated in in vitro model studies and in trials with cold-smoked salmon. addition of nisin caused various degrees of inhibition and sometimes death of l. monocytogenes in model experiments performed at 10 degrees c. the antilisterial effect of nisin was improved in the presence of 100% co2 and increasing nacl concentrations (0.5 to 5 ...19979506287
the role of actin binding proteins in epithelial morphogenesis: models based upon listeria movement.we summarize recent findings on the organization of the protein actin in eucaryotic cells. in particular we focus on how actin can be used to generate a vectorial force that is required for cell movement. these forces arise from protein molecules that recruit actin to the plasma membrane in such a manner that actin filaments extend outward from the cell body. this type of actin dependent force generation has been described in a nucleation-release model, which is one of several models currently b ...19979468611
the occurrence of listeria spp. and salmonella spp. in surface waters.listeria ssp., mainly listeria monocytogenes as well as salmonella spp. are recognized as significant human pathogens. the purpose of this study was to examine the occurrence of listeria spp. and salmonella spp. in surface waters of northern greece and to investigate the correlation of these pathogens with the standard indicator bacteria. a total number of 128 water samples from four rivers and one lake were examined for the presence of listeria, salmonella, total coliforms, faecal coliforms and ...19979468661
mutagenesis study of the glycosylphosphatidylinositol phospholipase c of trypanosoma brucei.the glycosylphosphatidylinositol phospholipase c (gpi-plc) from trypanosoma brucei is particularly effective in hydrolysing the gpi-anchors of some proteins. the enzyme is inhibited by zn2+ and p-chloromercurylphenylsulphonic acid, both of which can act as sulphydryl reagents, suggesting that a cysteine residue may be important in catalysis. single cysteine to serine mutants have been produced for all eight cysteines in gpi-plc; all the mutants were fully active in vitro and were still susceptib ...19979476790
activation of natural immune functions by pneumocystis carinii. 19979465880
immune privilege in the anterior chamber of the eye is not extended to intraocular listeria monocytogenes.resistance to many pathogens, such as listeria monocytogenes, is correlated with the host's capacity to generate a thi cell-mediated immune response in which delayed-type hypersensitivity (dth) is activated. a wide variety of antigens induce down-regulation of dth when introduced into the anterior chamber of the eye. this immunoregulatory phenomenon has been termed anterior chamber-associated immune deviation (acaid) and is believed to be a primary mechanism for the immune privilege of the anter ...19979455741
[the effect of listeria monocytogenes on the blood system].the influence of l. monocytogenes on the hemopoietic system was studied in mouse experiments. all elements of hemopoiesis were damaged. the most pronounced changes developed in erythropoiesis. this was testified by a decrease in erythrocyte count and hemoglobin content in peripheral blood, by the hypoplasia of the hemopoietic erythroid germ in the marrow, as well as by the decrease of yield in culture cfu-e. these changes in the hemopoietic tissue supposedly caused by the direct action of l. mon ...19979460871
addition of 2.5% lactate and 0.25% acetate controls growth of listeria monocytogenes in vacuum-packed, sensory-acceptable servelat sausage and cooked ham stored at 4 degrees c.a study of the inhibitory effects of propylparaben and of a combination of lactate and acetate against growth of listeria monocytogenes in inoculated liquid medium, sliced servelat sausage and cooked ham, were performed using rifampicin resistant listeria strains in inoculation experiments. a consumer acceptance test of products produced with and without the compounds was also performed. propylparaben was found to be effective in a model liquid non-fat medium, but was without effect in the actua ...19979498139
a pcr-microplate capture hybridization method to detect listeria monocytogenes in blood.in order to improve the diagnosis of listeria monocytogenes infection, we have developed a polymerase chain reaction (pcr)-based assay combined with microplate capture hybridization technique. the system is based on selective amplification of l. monocytogenes with two specific primers based on the iap gene. the amplicon produced, with digoxigenin 11-dutp incorporated during pcr, is hybridized in streptavidin-coated microtitre plates prepared with biotinylated specific dna probe. the method invol ...19979500808
single-strand conformation polymorphism (sscp) analysis of listeria monocytogenes iap gene as tool to detect different serogroups.pcr-single-strand conformation polymorphism (pcr-sscp) analysis is a convenient technique for the detection of mutations. as the mobility of single-stranded dna is sequence-dependent it could therefore be used to determine serotype-related sequence variations in listeria monocytogenes. sero-specific patterns were observed in different l. monocytogenes serogroups.19979500812
intensive (pasture) beef cattle operations: the perspective of new zealand.beef production in new zealand has characteristics typical of a temperate climate and pasture-based animal husbandry. the specific pathogens which may contaminate fresh beef and which are empirically considered to be of public health importance are similar to those in other countries with temperate climates, i.e. salmonella, campylobacter, escherichia coli o157:h7, listeria monocytogenes and toxoplasma gondii. with the exception of t. gondii, it is likely that almost all transmission of these ha ...19979501351
meat from dairy cows: possible microbiological hazards and risks.the authors provide an overview of the circumstances associated with culling of dairy cattle in the united states of america (usa) and focus on the possible significant microbiological hazards associated with meat from cull dairy cows. cull dairy cows are an important source of food in the usa, accounting for at least approximately 17% of ground beef. the potential microbiological hazards for foodborne illness from cull dairy cows discussed here include salmonella (with special attention to s. t ...19979501354
milk pasteurisation and safety: a brief history and update.a brief history of the development of milk pasteurisation is presented and updated. concerns about the margin of safety provided by current pasteurisation standards in terms of milk-borne pathogens such as mycobacteria (in particular mycobacterium paratuberculosis) and other emerging pathogens such as listeria monocytogenes and escherichia coli o157:h7 are discussed. with the exception of the endospores of bacillus cereus, current standards appear to be adequate for public health assurance of mi ...19979501358
[pathogenic organisms in milk and milk products: the situation in france and in europe].milk and dairy products harbour a natural microbial flora and/or other micro-organisms, which vary within the wide range of products available on the french market. the origin of contamination by pathogenic bacteria varies with the type of product and the mode of production and processing. contamination of milk and dairy products by pathogenic micro-organisms can be of endogenous origin, following excretion from the udder of an infected animal. contamination may also be of exogenous origin, thro ...19979501359
risks and prevention of contamination of dairy products.consumers and regulatory officials are becoming increasingly aware of the human health risk of the presence of micro-organisms or chemicals in the agricultural environment. providing 'on-farm food safety' programmes which address the daily management of the production unit with regard to animal health and well-being, public health and environmental health must be a top priority for agriculturalists and veterinarians. developing critical control point management (ccpm) procedures for animal and h ...19979501360
public health and pork and pork products: regional perspectives of denmark.an ambitious programme to eliminate pork as an important source of human salmonellosis was initiated in denmark in 1993 by the ministry of food, agriculture and fisheries. the programme comprises control of feedmills, breeding and multiplying herds, slaughter herds and slaughter plants, as well as the final product, fresh pork. as a consequence, the level of occurrence of salmonella spp. in fresh pork produced in denmark is approximately 1%. yersinia enterocolitica 0:3 infections are common in s ...19979501365
prolonged persistence of listeria monocytogenes after intragastric infection in corticosteroid-treated mice.in an attempt to obtain a model more closely resembling natural listeriosis, we studied the course of infection in mice inoculated by the intragastric route with listeria monocytogenes. corticosteroid-treated, and untreated mice both developed subclinical infection without mortality, but faecal shedding and persistence of bacteria in the liver and spleen of corticosteroid-treated mice were significantly more protracted than in untreated mice. untreated mice cleared the bacteria from their livers ...19979451464
comparative activities of new fluoroquinolones, alone or in combination with amoxicillin, trimethoprim-sulfamethoxazole, or rifampin, against intracellular listeria monocytogenes.we studied the activities of the new fluoroquinolones clinafloxacin, levofloxacin, ofloxacin, and sparfloxacin alone or in combination on the intracellular growth of listeria monocytogenes. against intracellular growth of the four strains tested, a similar reduction of the bacterial count was obtained with clinafloxacin at the dose of 10 x mic (delta log10 cfu/ml = -2.19 +/- 0.24), with levofloxacin at 8 x mic (delta log10 cfu/ml = -2.28 +/- 0.25), and with sparfloxacin at 4 x mic (delta log10 c ...19978980755
in vitro extracellular and intracellular activity of two newer and two earlier fluoroquinolones against listeria monocytogenes.two new fluoroquinolones (trovafloxacin and sparfloxacin) with enhanced activity against gram-positive pathogens and two earlier compounds (ciprofloxacin and ofloxacin) were tested for their in vitro inhibitory and bactericidal activity against 80 strains of listeria monocytogenes. all strains were uniformly highly susceptible to trovafloxacin, the mic90 being 0.25 mg/l. resistance to sparfloxacin was not detected, however the mic90 of sparfloxacin was eight times that of trovafloxacin. a few st ...19979447905
inhibition of listeria monocytogenes by enterocin 4 during the manufacture and ripening of manchego cheese.the inhibitory effect of enterocin 4, a bacteriocin produced by enterococcus faecalis inia 4, on listeria monocytogenes strains ohio and scott a during the manufacture and ripening of manchego cheese was investigated. raw ewe's milk was inoculated with ca 10(5) cfu ml-1 of l. monocytogenes and with 1% of a commercial lactic starter, 1% of an ent. faecalis inia 4 culture, or 1% of each culture. manchego cheeses were manufactured according to usual procedures. listeria monocytogenes ohio counts de ...19979449804
a universal protocol for pcr detection of 13 species of foodborne pathogens in foods.a universal protocol for pcr detection of 13 species of foodborne pathogens in foods was developed. the protocol used a universal culture medium and the same pcr conditions with 13 sets of specific primers. the 13 species of foodborne pathogens examined were escherichia coli, e. coli-etec, e. coli-o157:h7, shigella spp., salmonella spp., yersinia enterocolitica, y. pseudotuberculosis, vibrio cholerae, v. parahaemolyticus, v. vulnificus, listeria monocytogenes, staphylococcus aureus and bacillus ...19979449811
effects of gamma irradiation on the survival of listeria monocytogenes and on its growth at refrigeration temperature in poultry and red meat.gamma irradiation sensitivity of a strain of listeria monocytogenes was determined in trypticase soy broth supplemented with yeast extract (tsb-ye), in a slurry of chicken breast meat and in raw ground beef. d10 values in these different media were 0.364, 0.599, and 0.699 kgy, respectively. this organism appeared most sensitive in tsb-ye, more resistant in minced fresh chicken breast meat, and most resistant in fresh minced beef. it was found that irradiation at 2.5 kgy prior to refrigeration is ...19979438279
interleukin-12 promotes enhanced resistance to listeria monocytogenes infection of lead-exposed mice.the heavy metal lead (pb) has been shown to downregulate various parameters of cell-mediated immune (cmi) responses. this inhibition of cmi responses by pb is exemplified by a higher mortality rate upon infections with sublethal doses of a variety of pathogens. unlike pb, which lowers host resistance, interleukin-12 (il-12) exerts a substantial stimulatory influence on the host response to intracellular bacteria such as listeria monocytogenes. to explore the influence of il-12 in mice rendered s ...19979439714
host-pathogen interactions during entry and actin-based movement of listeria monocytogenes.listeria monocytogenes is a pathogenic bacterium that induces its own uptake into mammalian cells, and spreads from one cell to another by an actin-based motility process. entry into host cells involves the bacterial surface proteins inla (internalin) and inlb. the receptor for inla is the cell adhesion molecule e-cadherin. inlb-mediated entry requires activation of the host protein phosphoinositide (pi) 3-kinase, probably in response to engagement of a receptor. actin-based movement of l. monoc ...19979442892
the host response to listeria monocytogenes mutants defective in genes encoding phospholipases c (plca, plcb) and actin assembly (acta).several genes involved in the determination of listeria monocytogenes pathogenesis have been identified. among them, plca gene encodes phosphatidylinositol-specific phospholipase c (pi-plc), plcb gene encodes a broad-range phospholipase c (pc-plc), and acta encodes a protein contributing to actin assembly in infected cells. the interaction of l. monocytogenes wild type (lo 28) strain and two derivative mutants, plca- (bug 206) and acta-/plcb- (lut 12), with macrophages and t lymphocytes was inve ...19979444325
[the computed tomographic and magnetic resonance aspects in meningoencephalitis due to listeria monocytogenes. a case report]. 19979446135
[acute hydrocephalus and brain abscess in listeria monocytogenes meningitis]. 19979432203
[the gas trophicity of pathogenic bacteria].yersinia pseudotuberculosis and listeria have been shown to be capable of assimilating carbon dioxide from the air and using its carbon for the synthesis of biopolymers of the bacterial cell. these microorganisms, the causative agents of saprozoonotic infections, have also been found to be capable of assimilating molecular nitrogen from the air in small amounts. the data on the influence of the growth conditions of the cultures (hydrogen concentration, the presence of carbon dioxide and oxygen, ...19979432851
[the ecological aspects of listeriosis in the maritime territory].in the process of batch cultivation the strains under study are capable of prolonged growth at low temperature in rich and poor nutrient media (with the term of observation equal to 4 months), while at a temperature of 37 degrees c microbial populations quickly die (in 8-35 days). in the absence of compounds containing carbon, hydrogen and nitrogen in the nutrient medium, listeria can proliferate under such conditions. as established with the use of gas chromatography and the radioisotopic metho ...19979432856
discrimination of listeria monocytogenes strains of serotype 4b by restriction enzyme analysis of chromosomal dna.epidemiologically related cheese and environmental strains and epidemiologically unrelated strains of listeria monocytogenes serotype 4b were examined by restriction enzyme analysis of chromosomal dna with a total of 10 restriction enzymes. the dna fingerprint patterns generated from each restriction enzyme digest of total dna of all strains were classified. the restriction enzyme patterns of seven strains recovered from cheese and environmental samples in the same plant were identical to each o ...19979559441
a broad-host-range mobilizable shuttle vector for the construction of transcriptional fusions to beta-galactosidase in gram-positive bacteria.a low-copy-number vector designated ptcv-lac has been constructed to provide a convenient system to analyze regulatory elements in gram-positive bacteria. the main components of this vector are: (i) the origins of replication of pacyc184 and of the broad-host-range enterococcal plasmid pam beta 1, (ii) erythromycin- and kanamycin-resistance-encoding genes for selection in gram-negative and gram-positive bacteria, (iii) the transfer origin of the incp plasmid rk2, and (iv) a promoterless beta-gal ...19979513264
[presence of listeria monocytogenes and listeria sp. in fresh and cured sausages. use of different conditions of time and temperature for incubation].two different temperatures for enrichment of listeria monocytogenes and related species have been studied (1) cold enrichment at 4 degrees c (2) enrichment at 30 degrees c (fda method). also, two selective media for isolation were tested: acriflavine-ceftazidime agar (a.c.) and palcam agar. we have studied 72 samples of dry-cured sausage (called 'longaniza') at different stages of maturation: fresh, semi-cured and cured samples. the most efficient method was cold enrichment at 4 degrees c during ...19979467304
effects of avgard treatment on the microbiological flora of poultry carcases.1. the efficiency of the avgard (or assur-rince in the usa) trisodium phosphate poultry carcase decontamination process was evaluated during both manual and industrial trials against total aerobic mesophilic count (tamc), thermotolerant coliforms, pseudomonas, enterobacteriaceae, campylobacter, listeria monocytogenes and salmonella. 2. the tsp treatment proved to have significant effects on the bacterial decontamination of poultry neck skin, lowering the contamination by a factor of about 10 for ...19979510992
minimal inhibitory concentrations and minimal bactericidal concentrations of quinupristin/dalfopristin against clinical isolates of corynebacterium jeikeium and listeria monocytogenes.thirty clinical isolates of listeria monocytogenes and 30 clinical isolates of corynebacterium jeikeium were tested against quinupristin/dalfopristin by the nccls broth macrodilution technique for determination of mics. mbc testing was also performed on the 60 isolates. quinupristin/dalfopristin mic90 values against l. monocytogenes and c. jeikeium were 1.6 mg/l and 0.2 mg/l, respectively. quinupristin/dalfopristin was bacteriostatic against these organisms.19979511066
cell proliferation enhances entry of listeria monocytogenes into intestinal epithelial cells by two proliferation-dependent entry pathways.bacterial entry into intestinal host cells is the result of a fairly sophisticated manipulation of host cell machinery by the pathogens. to study further the potential cell target of listeria spp., the in-vitro entry of l. monocytogenes strains into intestinal cells was examined in relation to the metabolism, proliferation and differentiation of the cells by the alamarblue assay, [3h] thymidine incorporation, and brush border-associated enzyme activities, respectively. the study showed that cell ...19979511817
effect of saline concentration, ph and growth temperature on the invasive capacity of listeria monocytogenes.the invasive ability of listeria monocytogenes was monitored after treatment at different ph, temperature and salt concentrations. we found a complete loss of invasive ability in bacteria grown at ph < or = 4.5 independently of the incubation temperature (4, 22 and 30 degrees c). increasing salt concentrations at 22 and 30 degrees c had no effect at ph 7, while drastically affecting invasive ability at ph 5. the expression of two proteins of 30 and 88 kda, extracted from the culture supernatant ...19979765809
a nested pcr method to detect listeria monocytogenes in artificially contaminated blood specimens.a nested pcr-based test was developed for the detection of listeria monocytogenes in blood specimens from patients with listeriosis. two pairs of oligonucleotide primers were designed to amplify a 1395-bp and a 453-bp fragment of the iap gene of l. monocytogenes. amplified products were analysed with gel electrophoresis and stained with ethidium bromide. the pcr method described could be routinely used to diagnose listeriosis.19979765826
evidence for a bacteriocin-like substance produced by a new strain of streptococcus sp., inhibitory to gram-positive food-borne pathogens.a new strain of streptococcus sp. (cncm i-841) isolated from a commercial probiotic product was shown to be antagonistic towards several food-borne pathogens including clostridium sp. and listeria monocytogenes. this strain produced and excreted an antibacterial substance in mrs broth. the inhibitory substance was different from hydrogen peroxide, since it was unaffected by catalase. it was sensitive to proteolytic enzymes, indicating that the active moiety of the inhibitor was proteinaceous in ...19979765859
inhibition of listeria monocytogenes and salmonella enteriditis by combinations of plant oils and derivatives of benzoic acid: the development of synergistic antimicrobial combinations.this study describes inhibitory properties of combinations of oil of fennel, oil of anise or oil of basil with either benzoic acid or methyl-paraben against listeria monocytogenes and salmonella enteriditis. micro-organisms were cultured at 37 degrees c in broth and viable counts measured over a 48-h period. s. enteriditis was particularly sensitive to inhibition by a combination of oil of anise, fennel or basil with methyl-paraben where there was < 10 cfu/ml after 1 h. l. monocytogenes was less ...19979552716
new and emerging pathogens, part 3. threats from the food we eat. 199610156107
monolaurin and acetic acid inactivation of listeria monocytogenes attached to stainless steel.individual and combined antimicrobial effects of monolaurin and acetic acid on listeria monocytogenes planktonic cells or stainless-steel-adherent cells were determined in order to evaluate cell viability during a 25-min exposure period at 25 degrees c. a 10(7)-colony-forming units (cfu)/ml population of planktonic cells was completely inactivated by the synergistic combination of 1% acetic acid with 50 or 100 microg/ml of monolaurin within 25 or 20 min, respectively. either compound alone cause ...199610463441
combined effects of packaging atmosphere and lactic acid on growth and survival of listeria monocytogenes in crayfish tail meat 4 degrees c.the effect of lactic acid on growth and survival of listeria monocytogenes in crayfish tail meat stored under refrigeration and various gas environments was investigated. frozen crayfish tail meat was thawed overnight, autoclaved, cooled, and inoculated with approximately 4 log colony-forming units (cfu) of a mixed-strain (scott a and f5027) l. monocytogenes culture per gram of meat. inoculated samples were blended with 0, 0.5, 1.0, 1.5, or 2.0% lactic acid and packaged under air, vacuum, or mod ...199610463442
effect of antibacterial antibody on bactericidal activities of superoxide and lysosomal enzyme from alveolar macrophages in rabbits.alveolar macrophages (am) have many fc receptors for igg, but are less reactive to lymphokines. they have a well-developed oxidative metabolism and contain large amounts of lysosomal enzyme. this suggests that the antibacterial antibody plays an important role in early resistance by am to intracellular bacterial infection and that a bactericidal agent, dependent on oxygen and lysosomal enzyme, participates in the effects of the antibacterial antibody on bactericidal activities of superoxide (o2- ...19969434328
hemolytic activity reevaluation of putative nonpathogenic listeria monocytogenes strains.identification of 12 strains originally characterized as nonpathogenic listeria monocytogenes was reassured following the evaluation of their hemolytic capability with a newly developed horse blood agar plate. seven of the strains were observed consistently to be hemolytic and confirmed as l. monocytogenes with the use of two commercial systems: the gene-trak l. monocytogenes-specific colorimetric dna hybridization assay and the api listeria system. except for one strain that formed typical smoo ...19968984907
[erythromycin-induced hearing loss in a patient with listeria monocytogenes meningo-ventriculitis].we report a 43-year-old woman who suffered from listeria monocytogenes meningitis. she was admitted to our hospital because of headache, nausea, vomiting, and fever. on admission she had no abnormal neurological signs except for severe nuchal stiffness. cerebrospinal fluid (csf) examination on the day of admission revealed pleocytosis and increased total protein level. the csf culture demonstrated listeria monocytogenes. because ampicillin therapy was not effective, erythromycin (8 g/day) was ad ...19968976138
the incidence and level of listeria monocytogenes contamination of food sources at primary production and initial processing.listeria monocytogenes was isolated in low numbers from a variety of environmental samples associated with the primary production of food, including vegetation, faeces and meat. the organism was rarely detected on growing grass and vegetables prior to processing. the excretion of l. monocytogenes by farm animals was linked to their diet, with animals fed entirely on hay or manufactured diets not excreting detectable levels of listeria (i.e. absence in 25 g). however, animals fed on silage, which ...19968972091
a foodborne outbreak of gastroenteritis involving listeria monocytogenes.an outbreak of gastroenteritis occurred in italy among 39 persons who had attended a private supper. all guests were previously healthy, young, non-pregnant adults; 18 (46%) had symptoms, mostly gastrointestinal (78%), with a short incubation period. four were hospitalized with acute febrile gastroenteritis, two of whom had blood cultures positive for listeria monocytogenes. no other microorganisms were recovered from the hospitalized patients' specimens. epidemiological investigation identified ...19968972666
sorting signals and targeting of infectious agents through axons: an annotation to the 100 years' birth of the name "axon".a brief review is given on mechanisms by which axons may be initiated during development and by which the polarity of neurons is maintained by selective sorting and delivery of molecules to axons and dendrites. the use of viruses as tools to study targeting of newly synthesized proteins to axons is described. emphasis is then given to the hazards that are presented to the individual by the retrograde transport of infectious agents in axons to the brain. borna disease virus, prions, and listeria ...19968973836
changes in cell morphology of listeria monocytogenes and shewanella putrefaciens resulting from the action of protamine.protamine, which is an antibacterial basic peptide, was shown to alter the cell morphology of listeria monocytogenes and shewanella putrefaciens. atomic force microscopy revealed that protamine smoothed the surface of cells, formed holes in the cell envelope, and caused fusion of s. putrefaciens cells. immunoelectron microscopy of protamine-treated cells of both l. monocytogenes and s. putrefaciens showed great damage to the cell wall and condensation of the cytoplasm. respiration of the cells w ...19968975598
cold stress proteins induced in listeria monocytogenes in response to temperature downshock and growth at low temperatures.listeria monocytogenes is a food-borne pathogen with the ability to grow at refrigerator temperatures. twelve cold shock proteins (csps) with apparent m(r)s of 48,600, 41,000, 21,800, 21,100, 19,700, 19,200, 18,800, 18,800, 17,200, 15,500, 14,500, and 14,400 were induced by cold shocking l. monocytogenes 10403s from 37 to 5 degrees c, as revealed by labeling with l-[35s]methionine followed by two-dimensional gel electrophoresis. strain slcc53 showed a similar response. cold acclimation proteins ...19968975605
the focal-adhesion vasodilator-stimulated phosphoprotein (vasp) binds to the proline-rich domain in vinculin.in mammalian cells vasodilator-stimulated phosphoprotein (vasp) is localized to focal adhesions and areas of dynamic membrane activity where it is thought to have a role in actinfilament assembly. the proteins responsible for recruiting vasp to these sites within the cell are not known. the bacterial protein acta binds vasp via a proline-rich motif that is very similar to a sequence in the proline-rich region of the focal-adhesion protein vinculin. we have examined the ability of vasp, synthesiz ...19968836115
interferon-gamma and interleukin-10 have cross-regulatory roles in modulating the class i and class ii mhc-mediated presentation of epitopes of listeria monocytogenes by infected macrophages.ifn-gamma is an important cytokine in resistance to infection with listeria monocytogenes, and interleukin 10 is known to exacerbate infection with listeria and other intracellular pathogens. we examined the effects of these cytokines on antigen presentation by macrophages infected with live listeria. listeriolysin o, a hemolysin secreted by listeria, is an immunodominant antigen presented by both class i and class ii mhc on infected cells. thioglycollate-elicited macrophages were pretreated wit ...19968836921
protein p60 participates in intestinal host invasion by listeria monocytogenes.the role of p60 in intestinal invasion by listeria monocytogenes was assessed after oral infection of mice with the p60 low-expressing mutant riii, or with anti-p60 antibody coated wild-type egd. invasion by l. monocytogenes riii bacteria has been unimpaired suggesting that a low density of p60 suffices for entry. up to 24 h post infection (p.i.), intestinal penetration by l. monocytogenes egd bacteria was markedly reduced by coating with anti-p60 antibodies. in histological sections, anti-p60 a ...19968837387
effect of immunomodulation with galactoside-specific mistletoe lectin on experimental listeriosis.balb/c-mice (n = 10 per experimental group) were intravenously infected with 5 x 10(4) and 5 x 10(5) viable cells of listeria monocytogenes slcc 4013. about 50-80 h after this challenge, all mice of the untreated control groups succumbed to their infection. pretreatment of experimental animals on the optimal immunoactive schedule with the galactoside-specific mistletoe lectin (ml-1; 1 ng/kg body weight; days 1, 4, 5, 6 before challenge), however, evidently reduced the lethality of listerial infe ...19968837402
listeria monocytogenes infection in a patient treated with methotrexate for rheumatoid arthritis. 19968838541
mena, a relative of vasp and drosophila enabled, is implicated in the control of microfilament dynamics.drosophila enabled is required for proper formation of axonal structures and is genetically implicated in signaling pathways mediated by drosophila abi. we have identified two murine proteins, mena and evl, that are highly related to enabled as well as vasp (vasodilator-stimulated phosphoprotein). a conserved domain targets mena to localized proteins containing a specific proline-rich motif. the association of mena with the surface of the intracellular pathogen listeria monocytogenes and the g-a ...19968861907
subtyping listeria monocytogenes isolates genetically related to the swiss epidemic clone.macrorestriction analysis by pulsed-field gel electrophoresis was used to assess the diversity of strains within the epidemic-associated electrophoretic type 1 (et1) clone of listeria monocytogenes. for this purpose, a total of 144 isolates from switzerland shown by multilocus enzyme electrophoresis to belong to the et1 were examined. these isolates were subtyped by macrorestriction analysis using the enzymes apai and smai and field inversion gel electrophoresis. among these 144 isolates, 45 wer ...19968862575
listeria spinal cord abscess--clinical and mri findings.intramedullary spinal cord abscess due to listeria monocytogenes is an uncommon condition usually affecting immunocompromised patients.19968862846
a role for phosphoinositide 3-kinase in bacterial invasion.listeria monocytogenes is a bacterial pathogen that invades cultured nonphagocytic cells. inhibitors and a dominant negative mutation were used to demonstrate that efficient entry requires the phosphoinositide (pi) 3-kinase p85alpha-p110. infection with l. monocytogenes caused rapid increases in cellular amounts of pi(3, 4)p2 and pi(3,4,5)p3, indicating that invading bacteria stimulated pi 3-kinase activity. this stimulation required the bacterial protein inlb, host cell tyrosine phosphorylation ...19968864117
internalin must be on the bacterial surface to mediate entry of listeria monocytogenes into epithelial cells.entry of listeria monocytogenes into cultured epithelial cells requires production of internalin, a protein with features characteristic of some gram-positive bacterial surface proteins, in particular an lpxtg motif preceding a hydrophobic sequence and a few basic residues at its c-terminal end. by immunofluorescence and immunogold labelling, we show that in wild-type l. monocytogenes, internalin is present on the cell surface and has a polarized distribution similar to that of acta, another sur ...19968866480
the prevalence of listeria monocytogenes in the environment of dairy farms.the prevalence of listeria monocytogenes in the environment of dairy farms was surveyed from december 1993 to june 1994 in one city of hokkaido. l. monocytogenes was isolated from 3 out of 5 farms investigated. serovar 4b organism was isolated from the brain stem of a cow from one farm which was clinically diagnosed as having listeriosis. the same serovar of l. monocytogenes was also isolated from the rectal contents of a healthy cow, straw on the floor, straw in the barn, and silage scattered a ...19968867607
liver abscesses due to listeria monocytogenes.involvement of the liver in cases of listeria monocytogenes is uncommon. we report a case of hepatitis due to l. monocytogenes, with a pathological finding of multiple abscesses. blood cultures yielded l. monocytogenes. the patient died a few days after admission.19968868081
an essential role for acta in acid tolerance of rhizobium meliloti.the acta gene, which is disrupted by tn5 in the acid-sensitive mutant of rhizobium meliloti tg2-6, was cloned and sequenced. it encodes a protein of 541 amino acids with a calculated molecular mass of 57,963 da and an estimated pl of 9.0. the acta protein sequence has 30% identity, and much higher similarity (69%), with the cute protein of escherichia coli. like the cute mutant of e. coli, tg2-6 is sensitive to copper. the reconstructed wild-type acta gene complemented the low ph- and copper-sen ...19968868435
divergicin 750, a novel bacteriocin produced by carnobacterium divergens 750.divergicin 750, a bacteriocin produced by carnobacterium divergens 750, preferentially inhibited the growth of strains of carnobacterium and enterococcus. selected strains of listeria monocytogenes and clostridium perfringens were also inhibited. the bacteriocin was purified to homogeneity by ammonium sulfate precipitation and sequential s-sepharose, hydrophobic interaction and reversed phase chromatography. the complete amino acid sequence was determined by edman degradation. the peptide consis ...19968869500
h2-m3 restricted presentation of listeria monocytogenes antigens. 19968872487
major histocompatibility class i presentation of soluble antigen facilitated by mycobacterium tuberculosis infection.cell-mediated immune responses are essential for protection against many intracellular pathogens. for mycobacterium tuberculosis (mtb), protection requires the activity of t cells that recognize antigens presented in the context of both major histocompatibility complex (mhc) class ii and i molecules. since mhc class i presentation generally requires antigen to be localized to the cytoplasmic compartment of antigen-presenting cells, it remains unclear how pathogens that reside primarily within en ...19968876215
induction of nitric oxide synthase in bovine mononuclear phagocytes is differentiation stage-dependent.bovine monocytes and monocyte-derived macrophages (mdm) activated by various means were assessed for induction of inducible nitric oxide synthase (inos), using the griess assay, northern blotting and reverse transcription/polymerase chain reaction (rt-pcr). interferon-gamma (ifn-gamma) induced little, if any, inos expression and no production in mdm, although these cells responded to ifn-gamma in other regards. in contrasts, mdm produced copious amounts of no when stimulated with lps or salmonel ...19968877411
in-vitro activity of ramoplanin (a novel lipoglycopeptide), vancomycin, and teicoplanin against gram-positive clinical isolates from cancer patients.the in-vitro activities of ramoplanin, vancomycin, and teicoplanin against gram-positive organisms isolated from cancer patients were determined. ramoplanin was the most active agent tested inhibiting all isolates at a concentration of < or = 0.5 mg/l. although all isolates were also susceptible to vancomycin and teicoplanin, their activities were surpassed by that of ramoplanin. the activity of teicoplanin was moderately better than that of vancomycin against bacillus cereus, enterococcus faeci ...19968877541
a new prfa-regulated gene of listeria monocytogenes encoding a small, secreted protein which belongs to the family of internalins.a mutant of listeria monocytogenes egd was constructed that carries an extended deletion removing the entire prfa-regulated gene cluster from plca to plcb and a second deletion inactivating the inla gene. upon supplementation of this mutant with multiple gene copies of prfa, a protein of 30 kda was detected in the supernatant of the mutant strain. the gene encoding this protein was obtained by direct and inverse polymerase chain reaction using oligonucleotide primers that were deduced from parti ...19968878044
thermal and biological treatments to control psychrotrophic pathogens.over the past decade, advances in egg processing technologies have permitted commercial production of ultrapasteurized liquid whole egg (lwe) products with a shelf-life of greater than 10 wk at 4 c. the inactivation and control of psychrotrophic pathogens such as listeria monocytogenes and aeromonas hydrophila in extended shelf-life lwe and conventionally pasteurized egg products is an ongoing food safety concern. this manuscript reports on the common features of these two psychrotrophic pathoge ...19968878273
pulsed light and pulsed electric field for foods and eggs.two new technologies for use in the food industry are described. the first method discussed uses intense pulse of light. this pulsed light (purebright) process uses short duration flashes of broad spectrum "white" light to kill all exposed microorganisms, including vegetative bacteria, microbial and fungal spores, viruses, and protozoan oocysts. each pulse, or flash, of light lasts only a few hundred millionths of a second (i.e., a few hundred microseconds). the intensity of each flash of light ...19968878274
immune and inflammatory responses in tnf alpha-deficient mice: a critical requirement for tnf alpha in the formation of primary b cell follicles, follicular dendritic cell networks and germinal centers, and in the maturation of the humoral immune response.to investigate the role of tnf alpha in the development of in vivo immune response we have generated tnf alpha-deficient mice by gene targeting. homozygous mutant mice are viable and fertile, develop lymph nodes and peyer's patches and show no apparent phenotypic abnormalities, indicating that tnf alpha is not required for normal mouse development. in the absence of tnf alpha mice readily succumb to l. monocytogenes infections and show reduced contact hypersensitivity responses. furthermore, tnf ...19968879212
changes in microbial populations on fresh cut spinach.the microbial populations found on fresh-cut spinach leaves that were stored in gas permeable bags at 10 degrees c for 12 days were examined and identified. the microorganisms consisted of mesophilic aerobic bacteria, psychrotrophic bacteria, pseudomonadaceae, enterobacteriaceae, micrococcaceae, lactic acid bacteria and yeasts. populations of mesophiles, psychrotrophs, pseudomonadaceae and enterobacteriaceae increased sharply during the storage period. the initial populations were 10(7), 10(6), ...19968880301
listeriolysin o production and pathogenicity of non-growing listeria monocytogenes stored at refrigeration temperature.three haemolytic, pathogenic strains of listeria monocytogenes (a reference strain nctc 7973, a food-derived strain l70 and a human strain l94) and a control strain of listeria innocua l27 were held in phosphate-buffered saline (pbs) of ph 7.0 or 5.5 at 4 degrees c for 4 weeks. the number of viable cells did not change significantly during this storage (the cells were non-growing). titers of listeria listeriolysin o (llo) activity against washed human erythrocytes and the pathogenicity of non-gr ...19968880303
pathways of listeria monocytogenes contamination in the meat processing industry.one hundred and thirty-three isolates of listeria monocytogenes from deboned fresh meat, production environment, cold cuts from five meat processing plants and from one plant producing cured dried sausages, were characterized using multilocus enzyme electrophoresis. on the basis of electrophoretically demonstrable allelic variation at 21 enzyme loci, 21 electrophoretic types (ets) were distinguished. analysis of the genetic relationships among the 21 ets revealed two distinct clusters: cluster a ...19968880305
typing of listeria monocytogenes by monocin and phage receptors.one hundred strains of listeria monocytogenes from both sporadic and epidemic cases were typed by monocin production combined with phage receptor and reverse phage receptor methods. the monocin-phage combination gave 72 types with 100% typability and 97% reproducibility. the results were compared to those of serotyping, phage typing, ribotyping, multilocus enzyme electrophoresis, restriction enzyme analysis and rapd (random amplification of polymorphic dna). the monocin/phage types were comparab ...19968880312
incidence of listeria spp. in tropical fish.the incidence of listeria spp. in tropical fish and shellfish was studied. the isolation protocol included a pre-enrichment, followed by two selective enrichment steps and plating on three selective agars. listeria monocytogenes could be detected in 17.2% of finfish and 12.1% of shellfish. l. innocua was the most common species encountered. in 6.9% finfish and 5.6% shellfish, both l. monocytogenes and l. innocua were detected. polymerase chain reaction (pcr)-based amplification of internal fragm ...19968880320
the sub-typing of listeria monocytogenes isolates from food, environments surrounding food manufacturing sites, and clinical samples in new zealand using multilocus enzyme electrophoresis.listeria monocytogenes strains isolated from food (cheese, meat and fish), environments surrounding food manufacturing sites, and clinical samples from throughout new zealand were analyzed by multilocus enzyme electrophoresis. one hundred and twenty four strains were divided into 56 electrophoretic types, containing primarily clinical isolates and environmental isolates.19968880322
predictive models of the effect of temperature, ph and acetic and lactic acids on the growth of listeria monocytogenes.the combined effect of temperature (1-20 degrees c), ph (4.5-7.2) and acetic acid (0-10,000 mg/l; model 1) or lactic acid (0-20,000 mg/l; model 2) on growth of listeria monocytogenes in laboratory media was studied. growth curves at various combinations of temperature, ph and acid concentration were fitted by the model of baranyi and roberts (1994), and specific growth rates derived from the curve fit were modelled. predictions of growth from the models were compared with data in the literature, ...19968880329
predictive modeling of the growth of listeria monocytogenes in co2 environments.the effects of ph (5.5, 6.5), temperature (4, 7 and 10 degrees c) and carbon dioxide (10, 30, 50, 70 and 90%) on the growth and/or survival of a five strain mixture of listeria monocytogenes were examined in brain heart infusion broth. all three variables had a major influence on the growth characteristics of the organism. as expected, both the lag time and generation time increased as the co2 level increased, and as ph and temperature decreased. growth over a 30-day period was observed at all p ...19968880334
effects of carbon dioxide on the fate of listeria monocytogenes, of aerobic bacteria and on the development of spoilage in minimally processed fresh endive.minimally processed fresh broad-leaved endive (cichorium endivia l.) were stored at 3 and 10 degrees c in modified atmospheres containing air, 10% co2/10% o2, 30% co2/10% o2, and 50% co2/10% o2. the effects of these modified atmospheres on the fate of both aerobic bacteria and three strains of listeria monocytogenes, was investigated. increases in co2 concentrations significantly reduced the growth of the aerobic microflora. the best preservation of the visual quality occurred on endive leaves s ...19968880336
listeria monocytogenes in bovine mastitis. possible implication for human health.during the 23-year period 1972 through 1994 quarter milk samples from 1,132,958 cows originating from 36199 herds were examined for the presence of listeria monocytogenes. through the period the reference population amounted to 12,742,600 cow years and 401,682 herd years. the percentage of cows infected with l. monocytogenes varied from 0.01 to 0.1% (mean 0.04%) and of herds with an infected cow from 0.2 to 4.2% (mean 1.2%) through the period, showing a low but constant level of infection. a com ...19968880340
effect of combined lysozyme and lipase treatment on the survival of listeria monocytogenes.the effectiveness of polyphosphates or lipases to increase the lytic activity of lysozyme was evaluated both on listeria monocytogenes suspended in buffer and on growing cultures incubated at different temperatures. at 5 degrees c and 37 degrees c polyphosphates combined with lysozyme did not result in the decrease of the number of non-growing l. monocytogenes cells. at the same incubation conditions, the addition of lipase to lysozyme significantly enhanced the bactericidal activity of lysozyme ...19968880343
cd4+ cytolytic effectors are inefficient in the clearance of listeria monocytogenes.cytotoxic t lymphocytes (ctl) recognize and lyse target cells through the interaction of the t-cell receptor complex with the class i or class ii major histocompatibility complex (mhc). the production of class i-restricted ctl has been shown to be critical to the elimination of specific pathogens including listeria monocytogenes. however, the function of class ii-restricted ctl in the clearance of intracellular pathogens is poorly understood. h-2b beta 2-microglobulin-deficient mice (beta 2m-/-) ...19968881755
comparison of ribotyping, arbitrarily primed pcr, and pulsed-field gel electrophoresis for molecular typing of listeria monocytogenes.fifty-one clinical isolates of listeria monocytogenes (15 isolates from two outbreaks and 36 epidemiologically unrelated isolates) were typed by conventional serotyping, ribotyping (rt), pulsed-field gel electrophoresis (pfge), and arbitrarily primed pcr (ap-pcr). serotyping was unable to distinguish between related and unrelated strains of l. monocytogenes. each of the three molecular methods showed excellent typeability and reproducibility. restriction with ecori and pvuii gave 16 and 23 rt pa ...19968748263
common entry mechanisms. bacterial pathogenesis.the recent identification of e-cadherin as the cell-surface receptor for the listeria monocytogenes adhesin, internalin, indicates that pathogenic bacteria exploit a variety of host surface molecules for entry and that they may share some common strategies for uptake into host cells.19968805360
bacteria in the bloodstream are trapped in the liver and killed by immigrating neutrophils.the critical role of the liver in the resolution of systemic bacterial infections is well documented. in the case of listeria monocytogenes, approximately 60% of bacteria inoculated i.v. into mice are recovered in the liver at 10 min after infection. here we report that the listeria recovered at 10 min were distributed equally among the hepatocyte and nonparenchymal liver cell populations. the majority (>/= 75%) of these organisms were bound extracellularly as judged by their sensitivity to gent ...19968805652
suppression of ifn-gamma production from listeria monocytogenes-specific t cells by endogenously produced nitric oxide.the induction of nitric oxide (no) by ifn-gamma has been well documented in a variety of experimental settings, but so far there has been no report on whether the endogenously produced no can suppress ifn-gamma production. in the present study, cd4+ t cells from listeria monocytogenes-immune mice produced ifn-gamma upon stimulation with specific antigen and no was generated in culture. when ng-monomethyl-l-arginine (nmma) was added to the culture at a dose sufficient for the complete blockade of ...19968806814
il-10 production by adult human derived microglial cells.microglia, a population of central nervous system (cns) macrophages, have been demonstrated to support immune accessory and effector functions in the cns. numerous studies support the role of microglia in cns development and pathology, where activation of microglia is consistently noted. the current study investigated microglial immune functions under basal and activation conditions and assessed the ability of interleukin-10 (il-10), added exogenously or produced by microglia, to down-regulate m ...19968808789
enhanced in vitro engulfment of listeria monocytogenes by rabbit polymorphonuclear leukocytes in the presence of sera from immune rabbits.the role of immune serum in the engulfment of listeria monocytogenes by polymorphonuclear leukocytes (pmnls) of rabbits was documented employing an in vitro assay. three serovarieties of l. monocytogenes, viz. serovars 1/2a, 4a and 4b, were separately incubated with pmnls of nonimmune rabbit and high titre homologous or heterologous antisera. normal rabbit serum was used as control. the number of l. monocytogenes per neutrophil was counted in stained smears in each assay and opsonic indices were ...19968809545
differential regulation of the virulence genes of listeria monocytogenes by the transcriptional activator prfa.the two listeria monocytogenes strains egd and nctc 7973 display a different regulation pattern of their prfa-dependent genes. all prfa-dependent genes from l. monocytogenes nctc 7973 are much more efficiently transcribed in brain-heart infusion medium than those from strain egd. transcription of these genes in egd is, however, induced after shift into minimal essential medium (mem) to a level that is comparable to that of strain nctc 7973. expression of the internalin gene (inla) is also influe ...19968809771
copper and zinc exposure of zebrafish, brachydanio rerio (hamilton-buchaman): effects in experimental listeria infection.to investigate the effects of heavy metals on susceptibility of fish to listeriosis, normal zebrafish, brachydanio rerio (hamilton-buchanan), were exposed to varying concentrations of zinc (0.05, 0.15, and 0.25 mg/liter) and copper (0.05, 0.10, and 0.15 mg/liter). during copper exposure, this heavy metal did not accumulate in zebrafish kidney. unlike copper, a small amount of zinc accumulated in kidneys of fish exposed at 0.25 mg/liter. to estimate the effects of this heavy metal on listerial in ...19968812178
serotyping and esterase typing for analysis of listeria monocytogenes populations recovered from foodstuffs and from human patients with listeriosis in belgium.listeria monocytogenes strains isolated in belgium from different foodstuffs and in sporadic cases of human listeriosis were analyzed. the distribution of serovars differed in each of these populations. the bacteria isolated from cheeses and from human patients with listeriosis were further studied by esterase typing. the twenty esterase patterns defined were not equally distributed in these two populations. the secretion of the virulence determinant phosphatidylinositol-specific phospholipase c ...19968815071
mri appearances of listeria rhombencephalitis.listeria monocytogenes is a rare cause of central nervous system infection in the non-immunocomprised patient and 10% of these patients develop a rhombencephalitis. we present such a case and discuss the clinical, pathological and radiological features.19968826752
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