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modeling the growth of listeria monocytogenes on cut cantaloupe, honeydew and watermelon.a recent outbreak linked to whole cantaloupes underscores the importance of understanding growth kinetics of listeria monocytogenes in cut melons at different temperatures. whole cantaloupe, watermelon, and honeydew purchased from a local supermarket were cut into 10 ± 1 g cubes. a four-strain cocktail of l. monocytogenes from food related outbreaks was used to inoculate fruit, resulting in ~10(3) cfu/10 g. samples were stored at 4, 10, 15, 20, or 25 °c and l. monocytogenes were enumerated at ap ...201424290625
the polymyxin ceftazidime oxford medium as an alternative selective and differential medium for isolation of listeria monocytogenes from raw or unpasteurized food.the polymyxin ceftazidime oxford medium (pcom) was developed to recover listeria monocytogenes from raw or unpasteurized foods. it contains esculin-ferric ammonium citrate as indicator system for listeria growth, and ceftazidime and polymyxin b as selective agents, which are available in several latin american countries. comparison of pcom, modified oxford medium (mox) and tryptic soy agar with 0.6% yeast extract (tsaye) indicated that both selective media were equally effective at recovering fo ...201424290624
diminution of 2,3,5-triphenyltetrazolium chloride toxicity on listeria monocytogenes growth by iron source addition to the culture medium.tetrazolium salts (ttz) such as 2,3,5-triphenyltetrazolium chloride (ttc) are readily reduced by bacterial populations of various genus. the reduced form of these redox indicators is conspicuously colored allowing a quick and easy detection of growth. the studies are mainly confined to gram negative bacteria because of an important toxic effect of tetrazolium salts on gram positive bacteria. indeed, we observed an important impact of different tetrazolium salts on listeria monocytogenes growth, ...201424290619
mapping hfq-rna interaction surfaces using tryptophan fluorescence quenching.hfq is a posttranscriptional riboregulator and rna chaperone that binds small rnas and target mrnas to effect their annealing and message-specific regulation in response to environmental stressors. structures of hfq-rna complexes indicate that u-rich sequences prefer the proximal face and a-rich sequences the distal face; however, the hfq-binding sites of most rnas are unknown. here, we present an hfq-rna mapping approach that uses single tryptophan-substituted hfq proteins, all of which retain ...201424288369
effects of microgravity on the virulence of listeria monocytogenes, enterococcus faecalis, candida albicans, and methicillin-resistant staphylococcus aureus.to evaluate effects of microgravity on virulence, we studied the ability of four common clinical pathogens--listeria monocytogenes, methicillin-resistant staphylococcus aureus (mrsa), enterococcus faecalis, and candida albicans--to kill wild type caenorhabditis elegans (c. elegans) nematodes at the larval and adult stages. simultaneous studies were performed utilizing spaceflight, clinorotation in a 2-d clinorotation device, and static ground controls. the feeding rate of worms for killed e. col ...201324283929
crystal structure of the interferon gamma receptor alpha chain from chicken reveals an undetected extra helix compared with the human counterparts.interferon gamma (ifn-γ) is an important cytokine that induces antiviral, antiproliferative, and immunomodulatory effects on target cells, and is also crucial in the early defense against intracellular parasites, such as listeria monocytogenes and toxoplasma gondii. the biological activity of ifn-γ relies upon the formation of a complex with its 2 receptors, the interferon gamma alpha chain (ifngr1) and beta chain (ifngr2), which are type ii cytokine receptors. structural models of ligand-recept ...201424283193
determination of the relative level of detection of a qualitative microbiological measurement method with respect to a reference measurement method.performance of qualitative microbiological measurement methods where the results are either "o" (microorganism not detected) or "1" (microorganism detected) is described by their probability of detection (pod) function, i.e., the pod as a function of the level of contamination of the sample, expressed as cfu/g or cfu/ml, or by the level of detection (lodp), i.e., the contamination of the sample that is detected (measurement result "1") with a specified probability p. when it is impossible to obt ...201324282952
identification and partial characterization of a bacteriocin-like inhibitory substance (blis) from lb. bulgaricus k41 isolated from indigenous yogurts.forty-two strains of lactobacillus bulgaricus isolated from locally made yogurts were examined and compared for bacteriocin producing ability using spot on lawn assay which improved by taking photo and image processing. lb. bulgaricus k41 exhibited the highest inhibition level against indicators. k41 bacteriocin-like inhibitory substance is sensitive to proteolytic enzymes (proteinase k, pepsin, and trypsin) but α-amylase makes slight reduction in its activity and it is resistant to lipase. this ...201424279356
emerging infectious colitis.the present review will highlight recent advances in the knowledge of emerging pathogens causing infectious colitis and provide a description of the most important food-borne outbreaks.201424275672
characterization of antioxidant-antibacterial quince seed mucilage films containing thyme essential oil.in this study thyme essential oil (teo) concentrations ranging from 0% to 2.0%, incorporated in quince seed mucilage (qsm) film were used. antibacterial activity, physical, mechanical, barrier and antioxidant properties of qsm films were evaluated. the antimicrobial activity of the qsm films incorporated with thyme essential oil was screened against 11 important food-related bacterial strains by agar disc-diffusion assay. films containing 1% of thyme essential oil were effective against all test ...201424274540
the ubiquitous nature of listeria monocytogenes clones: a large-scale multilocus sequence typing study.listeria monocytogenes is ubiquitously prevalent in natural environments and is transmitted via the food chain to animals and humans, in whom it can cause life-threatening diseases. we used multilocus sequence typing (mlst) of ∼2000 isolates of l. monocytogenes to investigate whether specific associations existed between clonal complexes (ccs) and the environment versus diseased hosts. most ccs (72%) were not specific for any single source, and many have been isolated from the environment, food ...201424274459
riboflavin (vitamin b2 ) deficiency impairs nadph oxidase 2 (nox2) priming and defense against listeria monocytogenes.riboflavin, also known as vitamin b2 , is converted by riboflavin kinase (rfk) into flavin mononucleotide (fmn) and flavin adenine dinucleotide (fad), which are essential cofactors of dehydrogenases, reductases, and oxidases including the phagocytic nadph oxidase 2 (nox2). riboflavin deficiency is common in young adults and elderly individuals, who are at the coincidental risk for listeriosis. to address the impact of acute riboflavin deficiency on host defense against listeria monocytogenes (l. ...201424272050
development of a novel selective and differential medium for the isolation of listeria monocytogenes.a new medium (lecithin and levofloxacin [ll] medium) is described for the isolation of listeria monocytogenes from food samples. ll medium includes lecithin from soybeans for the detection of phosphatidylinositol-specific phospholipase c (pi-plc) and phosphatidylcholine-specific phospholipase c (pc-plc) produced by l. monocytogenes. levofloxacin is incorporated to inhibit the growth of microorganisms other than l. monocytogenes, especially bacillus cereus, shown to possess pi-plc and pc-plc acti ...201424271177
impacts of sample preparation methods on solubility and antilisterial characteristics of essential oil components in milk.essential oil components (eocs) have limited water solubility and are used at much higher concentrations in complex food matrices than in growth media to inhibit pathogens. however, the correlation between solubility and activity has not been studied. the objective of this work was to characterize the solubility of eocs in solvents and milk and correlate solubility with antilisterial activity. the solubilities of four eocs, thymol, carvacrol, eugenol, and trans-cinnamaldehyde, in water was signi ...201424271170
acquired resistance of listeria monocytogenes in and escaped from liver parenchymal cells to gentamicin is caused by being coated with their plasma membrane.after systemic infection, a majority of listeria monocytogenes invade liver parenchymal cells (lpc), replicate therein and spread to neighboring cells, suggesting that 3 different types of l. monocytogenes exist in the liver: l. monocytogenes being unable to invade lpc, residing in lpc, and escaped from infected lpc. although listeriolysin o (llo) participates in escape of l. monocytogenes from macrophages and l. monocytogenes is susceptible to gentamicin (gm), it remains elusive whether llo par ...201424269768
expression, purification and antibacterial activity of the channel catfish hepcidin mature peptide.hepcidins are small cysteine-rich cationic antimicrobial peptides. the channel catfish (ictalurus punctatus) hepcidin cdna has been characterized, but recombinant protein expression and purification was not reported. i. punctatus hepcidin is comprised of 96 residues, with eight functionally important conserved cysteine residues located in the c-terminal region of the mature peptide, suggesting that this region is responsible for the antibacterial activity. in this study, a cdna fragment (mch) en ...201424269761
synthesis and evaluation of antibacterial activity of quaternized biopolymer from klebsiella terrigena.microbial exopolymer with antimicrobial properties, in particular, has gathered considerable interest due to their enormous scope of modification and wide gamut of application. the purpose of present study was to evaluate the antibacterial spectrum of a chemically modified biopolymeric flocculant produced by klebsiella terrigena.201424268027
stevia rebaudiana bertoni as a natural antioxidant/antimicrobial for high pressure processed fruit extract: processing parameter optimization.response surface methodology was used to evaluate the optimal high pressure processing treatment (300-500 mpa, 5-15 min) combined with stevia rebaudiana (stevia) addition (0-2.5% (w/v)) to guarantee food safety while maintaining maximum retention of nutritional properties. a fruit extract matrix was selected and listeria monocytogenes inactivation was followed from the food safety point of view while polyphenoloxidase (ppo) and peroxidase (pod) activities, total phenolic content (tpc) and antiox ...201424262555
regulation of no synthesis, local inflammation, and innate immunity to pathogens by bet family proteins.transcriptional activation of the nos2 gene, encoding inducible nitric oxide synthase (inos), during infection or inflammation requires coordinate assembly of an initiation complex by the transcription factors nf-κb and type i interferon-activated isgf3. here we show that infection of macrophages with the intracellular bacterial pathogen listeria monocytogenes caused binding of the bet proteins brd2, brd3, and, most prominently, brd4 to the nos2 promoter and that a profound reduction of nos2 exp ...201424248598
beneficial innate signaling interference for antibacterial responses by a toll-like receptor-mediated enhancement of the mkp-irf3 axis.a major function of innate immune receptors is to recognize pathogen-associated molecular patterns and then evoke immune responses appropriate to the nature of the invading pathogen(s). because innate immune cells express various types of these receptors, distinct combinations of signaling pathways are activated in response to a given pathogen. although the conventional wisdom is that these signaling pathways cooperate with one another to ensure an effective host response, a more nuanced view re ...201324248350
[infective endocarditis caused by listeria monocytogenes: review of the literature and a case report].infective endocarditis caused by listeria monocytogenesis an extremely rare but usually aggressive disease. we have seen in recent years an increase in age of onset of this disease and a predilection for patients with valvular disease, especially prosthetic valve. the treatment of choice is ampicillin, which is combined with gentamicin for synergy. it is known that even with treatment the mortality is very high and higher than in other types of bacterial endocarditis. with optimal therapy, that ...201324248114
[infections by listeria monocytogenes].listeria monocytogenes infections have been poorly characterized in chile.201324248112
[main virulence factors of listeria monocytogenes and its regulation].listeria monocytogenesis a facultative intracellular pathogen, ubiquitous and aetiological agent of listeriosis. the main way of acquisition is the consumption of contaminated food and can cause serious medical conditions such as septicemia, meningitis and gastroenteritis, especially in children, immunocompromised individuals and seniors and abortions in pregnant women. an increase in cases of listeriosis worldwide has been reported and it is estimated that its prevalence in developed countries ...201324248111
[listeria monocytogenes]. 201324248110
post-parturient shedding of listeria monocytogenes in breast milk of infected mice. [corrected].the objectives of this study were to develop an animal model to study listeria monocytogenes infection during the peri-parturient period and identify sources of maternal shedding of the pathogen. peri-parturient mice were infected intragastrically with l. monocytogenes that expressed bacterial luciferase. mice were then imaged in vivo over time. secreted breast milk samples from mice infected after parturition were enriched and plated for culture and imaging. bioluminescence imaging technology w ...201324246517
bioprotection of ready-to-eat probiotic artichokes processed with lactobacillus paracasei lmgp22043 against foodborne pathogens.the survival of 3 pathogens listeria monocytogenes atcc19115, salmonella enterica subsp. enterica atcc13311, and escherichia coli atcc8739 was evaluated over time in ready-to-eat (rte) artichoke products processed or not with the probiotic strain lactobacillus paracasei lmgp22043. both probiotic and standard products (final ph about 4.0; aw = 0.98) dressed with oil and packaged in modified atmosphere were inoculated with pathogens at a level of about 3 log cfu/g and stored at 4 ºc for 45 d. path ...201324245894
fascin confers resistance to listeria infection in dendritic cells.ag-presenting dendritic cells (dcs) must survive bacterial infection to present ag information to naive t cells. the greater ability of dcs' host defense is evident from the report that dcs are more resistant to listeria monocytogenes than macrophages. however, the molecular mechanism of this resistance is unclear. we found that listeria replicate more slowly in wild-type dcs compared with fascin1 knockout dcs. this finding is significant because fascin1, an actin-bundling protein, is specifical ...201324244012
uv light inactivation of human and plant pathogens in unfiltered surface irrigation water.fruit and vegetable growers continually battle plant diseases and food safety concerns. surface water is commonly used in the production of fruits and vegetables and can harbor both human- and plant-pathogenic microorganisms that can contaminate crops when used for irrigation or other agricultural purposes. treatment methods for surface water are currently limited, and there is a need for suitable treatment options. a liquid-processing unit that uses uv light for the decontamination of turbid ju ...201424242253
cloning, characterization and effect of tmpgrp-le gene silencing on survival of tenebrio molitor against listeria monocytogenes infection.peptidoglycan recognition proteins (pgrps) are a family of innate immune molecules that recognize bacterial peptidoglycan. pgrp-le, a member of the pgrp family, selectively binds to diaminopimelic acid (dap)-type peptidoglycan to activate both the immune deficiency (imd) and prophenoloxidase (propo) pathways in insects. a pgrp-le-dependent induction of autophagy to control listeria monocytogenes has also been reported. we identified and partially characterized a novel pgrp-le homologue, from ten ...201324240808
novel antilisterial bacteriocin licheniocin 50.2 from bacillus licheniformis vps50.2 isolated from soil sample.to isolate and characterize bacteriocin, licheniocin 50.2, from soil bacteria identified as bacillus licheniformis.201424238327
the tuberculosis vaccine candidate bacillus calmette-guérin δurec::hly coexpressing human interleukin-7 or -18 enhances antigen-specific t cell responses in mice.bacillus calmette-guérin (bcg), the only approved tuberculosis vaccine, provides only limited protection. previously, we generated a recombinant derivative (bcg δurec::hly), which secretes the pore-forming toxin listeriolysin o (llo) of listeria monocytogenes. this vaccine shows superior protection against tuberculosis in preclinical models and is safe in humans. here we describe two new vaccine strains which express human interleukin-7 (hil)-7 or hil-18 in the genetic background of bcg δurec::h ...201324236077
lytic bacteriophages: potential interventions against enteric bacterial pathogens on produce.foodborne illnesses resulting from the consumption of produce commodities contaminated with enteric pathogens continue to be a significant public health issue. lytic bacteriophages may provide an effective and natural intervention to reduce bacterial pathogens on fresh and fresh-cut produce commodities. the use of multi-phage cocktails specific for a single pathogen has been most frequently assessed on produce commodities to minimize the development of bacteriophage insensitive mutants (bim) in ...201324228223
epidemiology of bacteremia in febrile infants in the united states.fever in infants is a common clinical dilemma. the objective of this study was to present data from hospital systems across the northeast, southeast, mid-west, and western united states to identify the pathogens causing bacteremia in febrile infants admitted to general care units.201324218461
temporal requirements for b cells in the establishment of cd4 t cell memory.cd4 t cell memory generation is shaped by a number of factors, including the strength and duration of tcr signaling, as well as the priming environment, all of which can be modified by b cells. studies using b cell-deficient mice indicate b cells play a critical role in generating effector and memory cd4 t cells; however, when and how b cells are acting to promote these responses has not yet been ascertained. in this study, we use anti-cd20 ab depletion of b cells at different times following li ...201324218454
microbiological quality of burrata cheese produced in puglia region: southern italy.burrata cheese is a popular typical italian food product, produced in puglia (an administrative region of southern italy), and this study investigated the microbiological quality of 404 samples of this cheese. the samples were analyzed in order to quantify escherichia coli and to detect the presence of staphylococcus aureus, salmonella spp., and listeria monocytogenes. no sample exceeded the values of e. coli set by ec regulation 1441/07 for some dairy products, while 15 (3.7%) samples tested co ...201324215706
use of germicidal uv light to reduce low numbers of listeria monocytogenes on raw chicken meat.listeria monocytogenes is a common constituent of the microbiological community in poultry processing plants and can be found in low numbers on raw poultry. raw meat is the most important source of this pathogen in commercial cooking facilities. germicidal uv light was tested as a means to kill l. monocytogenes inoculated onto broiler breast fillets. treatments at 800 μw/ cm(2) for 5 s to 5 min of exposure were tested against inocula of 35 to 60 cells per fillet. all fillets were sampled by rins ...201324215703
microbiological quality of milk in tanzania: from maasai stable to african consumer table.in tanzania, pastoralists such as the maasai and small urban farmers are responsible for the country's milk production, and 95% of the national milk supply is sold without regulation. this study was conducted using hygiene checklists and milk sampling to investigate milk quality and safety at various steps throughout the milk production chain. in regions of dar es salaam and lake victoria, 196 milk samples were collected: 109 samples of raw milk, 41 samples of packed or open served heat-treated ...201324215695
four-year monitoring of foodborne pathogens in raw milk sold by vending machines in italy.prevalence data were collected from official microbiological records monitoring four selected foodborne pathogens (salmonella, listeria monocytogenes, escherichia coli o157:h7, and campylobacter jejuni) in raw milk sold by self-service vending machines in seven italian regions (60,907 samples from 1,239 vending machines) from 2008 to 2011. data from samples analyzed by both culture-based and real-time pcr methods were collected in one region. one hundred raw milk consumers in four regions were i ...201324215694
mathematical models to predict kinetic behavior and growth probabilities of listeria monocytogenes on pork skin at constant and dynamic temperatures.in this study, mathematical models were developed to predict the growth probability and kinetic behavior of listeria monocytogenes on fresh pork skin during storage at different temperatures. a 10-strain mixture of l. monocytogenes was inoculated on fresh pork skin (3 by 5 cm) at 4 log cfu/cm(2). the inoculated samples were stored aerobically at 4, 7, and 10 °c for 240 h, at 15 and 20 °c for 96 h, and at 25 and 30 °c for 12 h. the baranyi model was fitted to l. monocytogenes growth data on palca ...201324215689
listeria monocytogenes in five sardinian swine slaughterhouses: prevalence, serotype, and genotype characterization.in a 3-year study (2008 to 2011) to estimate the prevalence and the contamination sources of listeria monocytogenes in pork meat in sardinia, italy, 211 samples were collected from five sardinian swine slaughterhouses: 171 samples from slaughtered pigs and 40 from the slaughterhouse environment. fifty l. monocytogenes isolates were characterized by pcr-based serotyping, presence of virulence-associated genes, and pulsed-field gel electrophoresis restriction analysis. the overall prevalence of l. ...201324215688
postenrichment population differentials using buffered listeria enrichment broth: implications of the presence of listeria innocua on listeria monocytogenes in food test samples.the recovery of low levels of listeria monocytogenes from foods is complicated by the presence of competing microorganisms. nonpathogenic species of listeria pose a particular problem because variation in growth rate during the enrichment step can produce more colonies of these nontarget cells on selective and/or differential media, resulting in a preferential recovery of nonpathogens, especially listeria innocua. to gauge the extent of this statistical barrier to pathogen recovery, 10 isolates ...201324215687
pickled egg production: inactivation rate of salmonella, escherichia coli o157:h7, listeria monocytogenes, and staphylococcus aureus during acidification step.based on current u.s. food and drug administration acidified foods guidelines, regulatory approval of commercial pickled egg production without a final heat treatment requires challenge studies. we conducted challenge studies to verify common pickled egg processing parameters. hard-boiled eggs were acidified in ambient temperature brine at a 60:40 egg/brine ratio. four acidification treatments were studied in triplicate: 5% acetic acid (aa) or 2.5% aa brine with and without 0.05% sodium benzoate ...201324215686
technological properties of bacteriocin-producing lactic acid bacteria isolated from pico cheese an artisanal cow's milk cheese.evaluate technologically relevant properties from bacteriocin-producing strains to use as starter/adjunct cultures in cheese making.201424206097
btla interaction with hvem expressed on cd8(+) t cells promotes survival and memory generation in response to a bacterial infection.the b and t lymphocyte attenuator (btla) is an ig super family member that binds to the herpes virus entry mediator (hvem), a tnf receptor super family (tnfrsf) member. engagement of btla by hvem triggers inhibitory signals, although recent evidence indicates that btla also may act as an activating ligand for hvem. in this study, we reveal a novel role for the btla-hvem pathway in promoting the survival of activated cd8(+) t cells in the response to an oral microbial infection. our data show tha ...201324205057
critical role of a ferritin-like protein in the control of listeria monocytogenes cell envelope structure and stability under β-lactam pressure.the human pathogen listeria monocytogenes is susceptible to the β-lactam antibiotics penicillin g and ampicillin, and these are the drugs of choice for the treatment of listerial infections. however, these antibiotics exert only a bacteriostatic effect on this bacterium and consequently, l. monocytogenes is regarded as β-lactam tolerant. it is widely accepted that the phenomenon of bacterial tolerance to β-lactams is due to the lack of adequate autolysin activity, but the mechanisms of l. monocy ...201324204978
genomic organization, sequence characterization and expression analysis of tenebrio molitor apolipophorin-iii in response to an intracellular pathogen, listeria monocytogenes.apolipophorin iii (apolp-iii) is a well-known hemolymph protein having a functional role in lipid transport and immune response of insects. we cloned full-length cdna encoding putative apolp-iii from larvae of the coleopteran beetle, tenebrio molitor (tmapolp-iii), by identification of clones corresponding to the partial sequence of tmapolp-iii, subsequently followed with full length sequencing by a clone-by-clone primer walking method. the complete cdna consists of 890 nucleotides, including an ...201424200961
identification of tlr10 as a key mediator of the inflammatory response to listeria monocytogenes in intestinal epithelial cells and macrophages.listeria monocytogenes is a gram-positive bacterium that can cause septicemia and meningitis. tlrs are central receptors of the innate immune system that drive inflammatory responses to invading microbes such as l. monocytogenes. although intestinal epithelial cells (iecs) represent the initial point of entry used by l. monocytogenes for infection, the innate immune response to l. monocytogenes in these cells has been poorly characterized to date. the aim of this study was to determine which tlr ...201324198280
immunosuppressive cd71+ erythroid cells compromise neonatal host defence against infection.newborn infants are highly susceptible to infection. this defect in host defence has generally been ascribed to the immaturity of neonatal immune cells; however, the degree of hyporesponsiveness is highly variable and depends on the stimulation conditions. these discordant responses illustrate the need for a more unified explanation for why immunity is compromised in neonates. here we show that physiologically enriched cd71(+) erythroid cells in neonatal mice and human cord blood have distinctiv ...201324196717
[resistance of listeria monocytogenes in simulated gastrointestinal systems].resistance of listeria monocytogenes was determined through its survival rate and intracellular ph (ph(i)) after exposed to in vitro digestion models.201324195384
crystallization and x-ray crystallographic analysis of the cholesterol-dependent cytolysin listeriolysin o from listeria monocytogenes.the secreted pore-forming toxin listeriolysin o (llo) from the intracellular pathogen listeria monocytogenes is a member of the family of cholesterol-dependent cytolysins (cdc) with broad properties in pathogenesis. its role as a virulence factor is enigmatic: it disrupts membranes and acts as an inductor of both pro- and anti-inflammatory responses in infected cells. in addition, llo is also a potent target for immunogenicity during infection. natively secreted llo from a recombinant l. innocua ...201324192351
listeriosis during pregnancy: a public health concern.listeria was first described in 1926 by murray, webb, and swann, who discovered it while investigating an epidemic infection among laboratory rabbits and guinea pigs. the role of listeria monocytogenes as a foodborne pathogen was definitively recognized during the 1980s. this recognition was the consequence of a number of epidemic human outbreaks due to the consumption of contaminated foods, in canada, in the usa and in europe. listeriosis is especially severe in immunocompromised individuals su ...201324191199
assessing in-house monitoring efficiency by tracing contamination rates in cheese lots recalled during an outbreak of listeriosis in austria.a cluster of 34 cases of listeriosis was traced to consumption of quargel cheese, a sour milk specialty, in austria, germany and czech republic between 2009 and 2010. after recall from the retail market all soft cheese batches (n = 18) were sent for investigation and iso 11290 based microbiological analysis revealed all red smear-ripened batches (16/18) to be positive for listeria monocytogenes whereas mold ripened cheeses were negative. the 16 positive batches were grouped into three categories ...201324184614
strain variability of the behavior of foodborne bacterial pathogens: a review.differences in phenotypic responses among strains of the same microbial species constitute an important source of variability in microbiological studies, and as such they need to be assessed, characterized and taken into account. this review provides a compilation of available research data on the strain variability of four basic behavioral aspects of foodborne bacterial pathogens including: (i) virulence; (ii) growth; (iii) inactivation; and (iv) biofilm formation. a particular emphasis is plac ...201324184609
foci of contamination of listeria monocytogenes in different cheese processing plants.listeria monocytogenes is a ubiquitous bacterium widely distributed in the environment that can cause a severe disease in humans when contaminated foods are ingested. cheese has been implicated in sporadic cases and in outbreaks of listeriosis worldwide. environmental contamination, in several occasions by persistent strains, has been considered an important source of finished product contamination. the objectives of this research were to (i) evaluate the presence of l. monocytogenes within the ...201324184608
an allelopathy based model for the listeria overgrowth phenomenon.in a standard procedure of food safety testing, the presence of the pathogenic bacterium listeria monocytogenes can be masked by non-pathogenic listeria. this phenomenon of listeria overgrowth is not well understood. we present a mathematical model for the growth of a mixed population of l. innocua and l. monocytogenes that includes competition for a common resource and allelopathic control of l. monocytogenes by l. innocua when this resource becomes limited, which has been suggested as one pote ...201424184260
listeria monocytogenes bacteremia and cmv colitis in a patient with ulcerative colitis. 201424183232
prevalence and characteristics of listeria monocytogenes in feces of black beef cattle reared in three geographically distant areas in japan.this study was conducted to determine the prevalence and characteristics of listeria monocytogenes in the feces of black beef cattle reared in geographically distant areas in japan. we surveyed 130 farms in the following three areas: northern (hokkaido prefecture), central (gifu and mie prefectures), and southern (oita, miyazaki, and kagoshima prefectures) areas and collected 1738 fecal samples. our data showed the following isolation rate for each area: northern, 11.4% of 651; central, 2.8% of ...201424180587
illuminating the petite picture of t cell memory responses to listeria monocytogenes.the ease to culture, moderately less safety constraints in handling, and above all, hurdle free induction of an anticipated infection in mouse rendered listeria monocytogenes the rank of a model organism for studying a variety of host immune responses. listeria monocytogenes being an intracellular pathogen evokes potent cd8 t cell response during which cd8 t cells pass through a massive expansion phase. this is generally followed by contraction phase wherein majority of activated cells undergo a ...201324171157
bactofencin a, a new type of cationic bacteriocin with unusual immunity.bacteriocin production is an important probiotic trait of intestinal bacteria. in this study, we identify a new type of bacteriocin, bactofencin a, produced by a porcine intestinal isolate lactobacillus salivarius dpc6502, and assess its potency against pathogenic species including staphylococcus aureus and listeria monocytogenes. genome sequencing of the bacteriocin producer revealed bfna, which encodes the mature and highly basic (pi 10.59), 22-amino-acid defensin-like peptide. matrix-assisted ...201324169573
sensitivity analysis for critical control points determination and uncertainty analysis to link fso and process criteria: application to listeria monocytogenes in soft cheese made from pasteurized milk.microbiological food safety is an important economic and health issue in the context of globalization and presents food business operators with new challenges in providing safe foods. the hazard analysis and critical control point approach involve identifying the main steps in food processing and the physical and chemical parameters that have an impact on the safety of foods. in the risk-based approach, as defined in the codex alimentarius, controlling these parameters in such a way that the fin ...201424168722
[analysis of the microbiological quality and potential presence of listeria monocytogenes in custard apple (annona muricata), mango (mangifera indica) and passion fruit (passiflora edulis) pulps from costa rica].the objective of this work was to determine some of the indicators associated to shelf life, hygiene, process and storage conditions for some of custard apple, mango and passion fruit pulps distributed by the main supermarket chains of the metropolitan area of san josé, costa rica, as well as to examine the potential presence of listeria monocytogenes in them. sixty fruit pulp samples were analyzed. tests included ph determination, total aerobic plate count, yeasts and mold count, lactic bacteri ...201324167958
seafood a potential source of some zoonotic bacteria in zagazig, egypt, with the molecular detection of listeria monocytogenes virulence genes.this article describes the results of a study conducted on 71 fresh seafood samples (fish and shellfish) marketed in zagazig city, sharkia province, egypt, as well as on 50 human stool samples collected at the zagazig university hospital. the samples were examined for the presence of listeria monocytogenes and escherichia coli. the investigation of l. monocytogenes virulence genes was performed using polymerase chain reaction (pcr), while the microbiological quality of the seafood samples was ev ...201324166481
dual mode of action of amylolysin: a type-b lantibiotic produced by bacillus amyloliquefaciens ga1.the partial genome sequencing of bacillus amyloliquefaciens ga1 led to the identification of the aml gene cluster involved in the synthesis of the novel lantibiotic named amylolysin. pure amylolysin was shown to have an antibacterial activity toward gram-positive bacteria including methicillin resistant staphylococcus aureus. the lantibiotic was also found efficient to inhibit the growth of listeria monocytogenes strains on poultry meat upon a long storage at 4°c. in silico analyses of the aml g ...201424164268
nod1 and nod2 enhance tlr-mediated invariant nkt cell activation during bacterial infection.invariant nkt (inkt) cells act at the crossroad between innate and adaptive immunity and are important players in the defense against microbial pathogens. inkt cells can detect pathogens that trigger innate receptors (e.g., tlrs, rig-i, dectin-1) within apcs, with the consequential induction of cd1d-mediated ag presentation and release of proinflammatory cytokines. we show that the cytosolic peptidoglycan-sensing receptors nod1 and nod2 are necessary for optimal ifn-γ production by inkt cells, a ...201324163408
confirmed low prevalence of listeria mastitis in she-camel milk delivers a safe, alternative milk for human consumption.she-camel milk is an alternative solution for people allergic to milk; unfortunately, potential harmful bacteria have not been tested in she-camel milk. listeria monocytogenes is one harmful bacterium that causes adverse health effects if chronically or acutely ingested by humans. the purpose of this study was to estimate the prevalence, characterize the phenotypic, genetic characterization, virulence factors, and antibiopotential harmful bacteria resistance profile of listeria isolated from the ...201424161878
prevalence and antimicrobial susceptibility of foodborne bacteria in wild boars (sus scrofa) and wild deer (cervus nippon) in japan.this study aimed to evaluate the role of wild boars and deer as reservoirs of foodborne bacteria. we investigated the prevalence and antimicrobial susceptibility of campylobacter spp., salmonella spp., shiga toxin-producing escherichia coli (stec) o157 and o26, and listeria monocytogenes isolated from wild boars and deer in japan, from july through december 2010. campylobacter spp. and salmonella spp. were isolated from 43.8% (95% confidence interval [ci]: 35.0-52.6) and 7.4% (95% ci: 2.8-12.1) ...201324161070
antibacterial efficacy of nisin, pediocin 34 and enterocin fh99 against listeria monocytogenes and cross resistance of its bacteriocin resistant variants to common food preservatives.antilisterial efficiency of three bacteriocins, viz, nisin, pediocin 34 and enterocin fh99 was tested individually and in combination against listeria mononcytogenes atcc 53135. a greater antibacterial effect was observed when the bacteriocins were combined in pairs, indicating that the use of more than one lab bacteriocin in combination have a higher antibacterial action than when used individually. variants of listeria monocytogenes atcc 53135 resistant to nisin, pediocin 34 and enterocin fh99 ...201324159285
formation of biofilm by listeria monocytogenes atcc 19112 at different incubation temperatures and concentrations of sodium chloride.biofilm formation can lead to various consequences in the food processing line such as contamination and equipment breakdowns. since formation of biofilm can occur in various conditions; this study was carried out using l. monocytogenes atcc 19112 and its biofilm formation ability tested under various concentrations of sodium chloride and temperatures. cultures of l. monocytogenes atcc 19112 were placed in 96-well microtitre plate containing concentration of sodium chloride from 1-10% (w/v) and ...201324159283
bio-preservation of ground beef meat by enterococcus faecalis cect7121.meat and particularly ground beef is frequently associated with food poisoning episodes and breeches in food safety. the main goal of this research was to evaluate the bactericide effect of the probiotic enterococcus faecalis cect7121, against different pathogens as: escherichia coli o157:h7, staphylococcus aureus, clostridium perfringens and listeria monocytogenes, inoculated in ground beef meat. three studies were performed to evaluate the inhibition of e. faecalis cect7121 on ground beef meat ...201324159282
confounding roles for type i interferons during bacterial and viral pathogenesis.although type i interferons (ifn-i) were initially defined as potent antiviral agents, they can also cause decreased host resistance to some bacterial and viral infections. the many antiviral functions of the ifn-i include direct suppression of viral replication and activation of the immune response against viruses. in addition to their antiviral effects, ifn-i are also protective against several extracellular bacterial infections, in part, by promoting the induction of tnf-α and nitric oxide. i ...201324158954
curcumin improves the therapeutic efficacy of listeria(at)-mage-b vaccine in correlation with improved t-cell responses in blood of a triple-negative breast cancer model 4t1.success of cancer vaccination is strongly hampered by immune suppression in the tumor microenvironment (tme). interleukin (il)-6 is particularly and highly produced by triple-negative breast cancer (tnbc) cells, and has been considered as an important contributor to immune suppression in the tme. therefore, we hypothesized that il-6 reduction may improve efficacy of vaccination against tnbc cancer through improved t-cell responses. to prove this hypothesis, we investigated the effect of curcumin ...201324156030
actin network disassembly powers dissemination of listeria monocytogenes.several bacterial pathogens hijack the actin assembly machinery and display intracellular motility in the cytosol of infected cells. at the cell cortex, intracellular motility leads to bacterial dissemination through formation of plasma membrane protrusions that resolve into vacuoles in adjacent cells. here, we uncover a crucial role for actin network disassembly in dissemination of listeria monocytogenes. we found that defects in the disassembly machinery decreased the rate of actin tail turnov ...201424155331
deficits in serum amyloid a contribute to increased neonatal mortality during murine listeriosis.to understand the increased susceptibility of preterm neonates to infection.201324153400
'prevalence and antimicrobial susceptibility of listeria monocytogenes and methicillin-resistant staphylococcus aureus strains from raw meat and meat products in zaria, nigeria.the bacterial genera listeria and staphylococcus have been frequently isolated from food products and are responsible for a number of animal and human diseases. the aim of the study was to simultaneously isolate and characterize l. monocytogenes and staphylococcus species from 300 samples of raw meat and meat products, to determine the susceptibility of the organisms to commonly used antimicrobial agents and to determine the presence of haemolysin a (hyl) virulence gene in l. monocytogenes and s ...201424151971
diversity and antimicrobial properties of lactic acid bacteria isolated from rhizosphere of olive trees and desert truffles of tunisia.a total of 119 lactic acid bacteria (lab) were isolated, by culture-dependant method, from rhizosphere samples of olive trees and desert truffles and evaluated for different biotechnological properties. using the variability of the intergenic spacer 16s-23s and 16s rrna gene sequences, the isolates were identified as the genera lactococcus, pediococcus, lactobacillus, weissella, and enterococcus. all the strains showed proteolytic activity with variable rates 42% were eps producers, while only 1 ...201324151598
novel antibacterial activity of lactococcus lactis subspecies lactis z11 isolated from zabady.the purpose of this study was to select and characterize a probiotic bacterium with distinctive antimicrobial activities. in this respect, lactococcus lactis subspecies lactis z11 (l. lactis z11) isolated from zabady (arabian yoghurt) inhibited other strains of lactic acid bacteria and some food-born pathogens including listeria monocytogenes, bacillus cereus and staphylococcus aureus. the inhibitory activity of cell free supernatant (cfs) of l. lactis z11 isolated from zabady was lost by proteo ...201324151453
characterization of a bacteriocin produced by lactococcus lactis subsp. lactis crl 1584 isolated from a lithobates catesbeianus hatchery.lactococcus lactis crl 1584 isolated from a lithobates catesbeianus hatchery inhibits the growth of citrobacter freundii (a bullfrog pathogen) and listeria monocytogenes by a synergistic effect between lactic acid, hydrogen peroxide and a bacteriocin-like molecule. the chemical characterization of the bacteriocin in cell-free supernatants indicates that it has a proteinaceous nature. hexadecane and ethyl acetate did not modify the bacteriocin activity, while 10 and 20 % (v/v) chloroform decrease ...201424150985
listeria monocytogenes (lm)-llo immunotherapies reduce the immunosuppressive activity of myeloid-derived suppressor cells and regulatory t cells in the tumor microenvironment.myeloid-derived suppressor cells (mdsc) and regulatory t cells (treg) are major components of the immune suppressive cells that potentially limit the effectiveness of an immunotherapy-based treatment. both of these suppressive cell types have been shown to expand in tumor models and promote t-cell dysfunction that in turn favors tumor progression. this study demonstrates that listeria monocytogenes (lm)-llo immunotherapies effect on the suppressive ability of mdsc and treg in the tumor microenvi ...201324145358
in vitro and in vivo models to study human listeriosis: mind the gap.listeria monocytogenes (lm) is the etiological agent of listeriosis, one of the deadliest human foodborne infections. lm is able to cross the intestinal, placental and blood-brain barriers, leading to septicemia, fetoplacental infection, meningitis and encephalitis. the intracellular life cycle of this facultative intracellular bacterium has been studied in detail in in vitro cell culture systems. lm enters in non-phagocytic cells in an inla-ecad and/or inb-met dependent manner. lm then escapes ...201324144539
lack of correlation between in vitro antibiosis and in vivo protection against enteropathogenic bacteria by probiotic lactobacilli.increased resistance to infection is one of the beneficial effects attributed to probiotic microorganisms. this effect may be due to several mechanisms: production of inhibitory substances, blocking of adhesion sites on the intestinal surface, competition for nutrients and stimulation of mucosal and systemic immunity. the present study aimed to investigate the correlation between in vitro and in vivo antimicrobial activity of probiotic lactobacilli. the agar spot test was used to show that twent ...201424140789
a non-catalytic histidine residue influences the function of the metalloprotease of listeria monocytogenes.mpl, a thermolysin-like metalloprotease, and pc-plc, a phospholipase c, are synthesized as proenzymes by the intracellular bacterial pathogen listeria monocytogenes. during intracellular growth, l. monocytogenes is temporarily confined in a membrane-bound vacuole whose acidification leads to mpl autolysis and mpl-mediated cleavage of the pc-plc n-terminal propeptide. mpl maturation also leads to the secretion of both mpl and pc-plc across the bacterial cell wall. previously, we identified negati ...201424140648
collaborative survey on the colonization of different types of cheese-processing facilities with listeria monocytogenes.cross-contamination via equipment and the food-processing environment has been implicated as the main cause of listeria monocytogenes transmission. the aim of this study, therefore, was to determine the occurrence and potential persistence of l. monocytogenes in 19 european cheese-processing facilities. a sampling approach in 2007-2008 included, respectively, 11 and two industrial cheese producers in austria and the czech republic, as well as six irish on-farm cheese producers. from some of the ...201424138033
genome sequences of listeria monocytogenes serotype 4b variant strains isolated from clinical and environmental sources.listeria monocytogenes strains that show a novel pcr serotyping profile (ivb-v1) have been reported recently. here, we announce the draft genome sequences of five l. monocytogenes ivb-v1 strains isolated from the united states and australia that harbor a 6.3-kb dna cassette characteristic of serotype 1/2a strains.201324136844
comparative proteomic analysis of listeria monocytogenes exposed to enterocin as-48 in planktonic and sessile states.enterocin as-48 is a cyclic peptide of great interest for application in food preservation and sanitation. in the present study, the proteome response of listeria monocytogenes to purified enterocin as-48 was studied under two different conditions: planktonic cells and sessile cells grown on polystyrene plates. ten different proteins were differentially expressed in planktonic l. monocytogenes cells treated with 0.1 μg/ml enterocin as-48 compared to the untreated controls. overexpressed proteins ...201324135676
challenges in listeriosis cluster and outbreak investigations, province of quebec, 1997-2011.public health authorities place a high priority on investigating listeriosis outbreaks, and these epidemiological investigations remain challenging. some approaches have been described in the literature to address these challenges. this review of listeriosis clusters and outbreaks investigated in the province of quebec (quebec) highlights investigative approaches that contributed to identifying the source of these outbreaks.201424134667
mycobacterium tuberculosis and the host cell inflammasome: a complex relationship.the production of il-1β during the infection with mycobacterium tuberculosis (mtb) is important for successful host immune defense. in macrophages and dendritic cells the host cell inflammasome is crucial for generation of secreted il-1β in response to mtb infections. in these cell types mtb infection only activates the nlrp3-inflammasome. new reports demonstrate that nitric oxide has an important function in the negative regulation of the nlrp3-inflammasome to reduce tissue damage during mtb in ...201324130966
co-culture with listeria monocytogenes within a dual-species biofilm community strongly increases resistance of pseudomonas putida to benzalkonium chloride.biofilm formation is a phenomenon occurring almost wherever microorganisms and surfaces exist in close proximity. this study aimed to evaluate the possible influence of bacterial interactions on the ability of listeria monocytogenes and pseudomonas putida to develop a dual-species biofilm community on stainless steel (ss), as well as on the subsequent resistance of their sessile cells to benzalkonium chloride (bc) used in inadequate (sub-lethal) concentration (50 ppm). the possible progressive a ...201324130873
anti-listeria activity of poly(lactic acid)/sawdust particle biocomposite film impregnated with pediocin pa-1/ach and its use in raw sliced pork.a novel poly(lactic acid) (pla)/sawdust particle (sp) biocomposite film with anti-listeria activity was developed by incorporation of pediocin pa-1/ach (ped) using diffusion coating method. sawdust particle played an important role in embedding pediocin into the hydrophobic pla film. the anti-listeria activity of the pla/sp biocomposite film incorporated with ped (pla/sp+ped) was detected, while no activity against the tested pathogen was observed for the control pla films (without sp and/or ped ...201324129155
yersinia enterocolitica inhibits salmonella enterica serovar typhimurium and listeria monocytogenes cellular uptake.yersinia enterocolitica biovar 1b employs two type three secretion systems (t3ss), ysa and ysc, which inject effector proteins into macrophages to prevent phagocytosis. conversely, salmonella enterica serovar typhimurium uses a t3ss encoded by salmonella pathogenicity island 1 (spi1) to actively invade cells that are normally nonphagocytic and a second t3ss encoded by spi2 to survive within macrophages. given the distinctly different outcomes that occur with regard to host cell uptake of s. typh ...201424126528
efficacy of bacteriophage listex™p100 combined with chemical antimicrobials in reducing listeria monocytogenes in cooked turkey and roast beef.the aim of this study was to verify the effectiveness of the commercially available anti-listeria phage preparation listex(™)p100 in reducing listeria monocytogenes on ready-to-eat (rte) roast beef and cooked turkey in the presence or absence of the chemical antimicrobials potassium lactate (pl) and sodium diacetate (sd). sliced rte meat cores at 4 and 10 °c were inoculated with cold-adapted l. monocytogenes to result in a surface contamination level of 10(3)cfu/cm(2). listex(tm)p100 was applied ...201324125778
hiv-1 vaccine-specific responses induced by listeria vector vaccines are maintained in mice subsequently infected with a model helminth parasite, schistosoma mansoni.in areas co-endemic for helminth parasites and hiv/aids, infants are often administered vaccines prior to infection with immune modulatory helminth parasites. systemic th2 biasing and immune suppression caused by helminth infection reduces cell-mediated responses to vaccines such as tetanus toxoid and bcg. therefore, we asked if infection with helminthes post-vaccination, alters already established vaccine induced immune responses. in our model, mice are vaccinated against hiv-1 gag using a list ...201324120546
outbreak of listeria monocytogenes in an urban poultry flock.listeria monocytogenes infection is most commonly recognized in ruminants, including cattle, sheep, and goats; but it is rarely diagnosed in poultry. this report describes an outbreak of l. monocytogenes in a backyard poultry flock. also, it points out the importance of collaboration between veterinarians and public health departments and the possible implications of zoonotic diseases.201324119838
antilisterial activity of lactose monolaurate in milk, drinkable yogurt and cottage cheese.lactose monolaurate (lml) was previously found to be an antimicrobial against listeria monocytogenes in culture medium at concentrations between 3 and 5 mg ml(-1) . in this study, the microbial inhibitory activity of lml in dairy products inoculated with a 5-strain cocktail of clinical isolates of l. monocytogenes was investigated. addition of lml at a concentration of 5 mg ml(-1) resulted in 4.4, 4.0 and 4.2 log reductions in 0.5% fat, 1% fat and 3.25% fat milks, respectively; 4.1, 4.4, and 3.5 ...201424117896
microbial diversity and structure are drivers of the biological barrier effect against listeria monocytogenes in soil.understanding the ecology of pathogenic organisms is important in order to monitor their transmission in the environment and the related health hazards. we investigated the relationship between soil microbial diversity and the barrier effect against listeria monocytogenes invasion. by using a dilution-to-extinction approach, we analysed the consequence of eroding microbial diversity on l. monocytogenes population dynamics under standardised conditions of abiotic parameters and microbial abundanc ...201324116193
biotic and abiotic soil properties influence survival of listeria monocytogenes in soil.listeria monocytogenes is a food-borne pathogen responsible for the potentially fatal disease listeriosis and terrestrial ecosystems have been hypothesized to be its natural reservoir. therefore, identifying the key edaphic factors that influence its survival in soil is critical. we measured the survival of l. monocytogenes in a set of 100 soil samples belonging to the french soil quality monitoring network. this soil collection is meant to be representative of the pedology and land use of the w ...201324116083
survival of listeria monocytogenes during production and ripening of traditional turkish savak tulum cheese and in synthetic gastric fluid.this study investigated the survival and acid tolerance of listeria monocytogenes during the 2-day processing stage and 90-day ripening of savak tulum cheese, a traditional cheese in turkey. experimental savak tulum cheese was produced from raw sheep's milk that was inoculated with a l. monocytogenes mixture consisting of five strains (average 7.0 log cfu/ml) and was ripened at 6°c for 90 days. microbiological and chemical analyses and acid exposure experiments in synthetic gastric fluid (sgf) ( ...201324112584
listeria infection inhibits ige production in regional lymph nodes by suppressing chemotaxis of basophils to lymph nodes.infection with listeria induces a dominant shift to the th1 immune response and inhibits the th2 response. papain is frequently utilized in animal models of allergies. papain administration induces chemotaxis of basophils to regional lymph nodes (lns) and production of interleukin (il)-4 by basophils, resulting in a th2-dominant status and increased ige production in lns. in this model, production of immunoglobulin (ig) e by ln cells is primarily controlled by il-4 produced by basophils. based o ...201324111499
listeria monocytogenes meningitis in adults: the czech republic experience.listeria monocytogenes (lm) is currently the third most frequent pathogen of bacterial meningitis in adults.201324106719
amythiamicin d and related thiopeptides as inhibitors of the bacterial elongation factor ef-tu: modification of the amino acid at carbon atom c2 of ring c dramatically influences activity.three analogues of amythiamicin d, which differ in the substitution pattern at the methine group adjacent to c2 of the thiazole ring c, were prepared by de novo total synthesis. in amythiamicin d, this carbon atom is (s)-isopropyl substituted. two of the new analogues carry a hydroxymethyl in place of the isopropyl group, one at an s- (compound 3 a) and the other at an r-configured stereogenic center (3 b). the third analogue, 3 c, contains a benzyloxymethyl group at an s-configured stereogenic ...201324106106
inactivation of the seca2 protein export pathway in listeria monocytogenes promotes cell aggregation, impacts biofilm architecture and induces biofilm formation in environmental condition.listeria monocytogenes has a dichotomous lifestyle, existing as an ubiquitous saprophytic species and as an opportunistic intracellular pathogen. besides its capacity to grow in a wide range of environmental and stressful conditions, l. monocytogenes has the ability to adhere to and colonize surfaces. morphotype variation to elongated cells forming rough colonies has been reported for different clinical and environmental isolates, including biofilms. this cell differentiation is mainly attribute ...201424102749
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