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listeria monocytogenes in food-processing facilities, food contamination, and human listeriosis: the brazilian scenario.listeria monocytogenes is a foodborne pathogen that contaminates food-processing environments and persists within biofilms on equipment, utensils, floors, and drains, ultimately reaching final products by cross-contamination. this pathogen grows even under high salt conditions or refrigeration temperatures, remaining viable in various food products until the end of their shelf life. while the estimated incidence of listeriosis is lower than other enteric illnesses, infections caused by l. monocy ...201728767285
characterisation of inla truncation in listeria monocytogenes isolates from farm animals and human cases in the province of quebec.the introduction of listeria monocytogenes into the food production chain is a concern, with numerous grouped cases of listeriosis associated with milk-derived or pork-derived products have been documented. management of this zoonotic pathogen considers all strains as an equal risk. recently, a new perspective for characterisation of strain virulence was introduced with the discovery of the unaltered sequence of inla as a determinant of strain virulence; this has also been reported as an infrequ ...201728761668
a role for host cell exocytosis in inlb-mediated internalisation of listeria monocytogenes.the bacterial surface protein inlb mediates internalisation of listeria monocytogenes into human cells through interaction with the host receptor tyrosine kinase, met. inlb-mediated entry requires localised polymerisation of the host actin cytoskeleton. apart from actin polymerisation, roles for other host processes in listeria entry are unknown. here, we demonstrate that exocytosis in the human cell promotes inlb-dependent internalisation. using a probe consisting of vamp3 with an exofacial gre ...201728745416
fasting metabolism modulates the interleukin-12/interleukin-10 cytokine axis.a crucial role of cell metabolism in immune cell differentiation and function has been recently established. growing evidence indicates that metabolic processes impact both, innate and adaptive immunity. since a down-stream integrator of metabolic alterations, mammalian target of rapamycin (mtor), is responsible for controlling the balance between pro-inflammatory interleukin (il)-12 and anti-inflammatory il-10, we investigated the effect of upstream interference using metabolic modulators on th ...201728742108
antibacterial activity of timsen(®) (n-alkyl dimethyl benzyl ammonium chloride-40%) in scalding and precooling water in poultry slaughterhouses.the objective of this study was to evaluate the efficacy of a product based on n-alkyl dimethyl benzyl ammonium chloride-40%, marketed as timsen(®), during scalding and precooling of poultry carcasses in slaughterhouses. to this end, three poultry slaughterhouses (a, b and c) were evaluated. the product was added (200 ppm) to the scalding (58 °c) and precooling water (4 °c), and microbiological analyses were performed of the water and the poultry carcasses before and after timsen(®) addition. th ...201728740319
nuclear carbonic anhydrase 6b associates with prmt5 to epigenetically promote il-12 expression in innate response.interleukin-12 (il-12) is critical for induction of protective immunity against intracellular bacterial infection. however, the mechanisms for efficient induction of il-12 in innate response remain poorly understood. here we report that the b type of carbonic anhydrase 6 (car6-b, which encoded ca-vi b) is essential for host defense against listeria monocytogenes (lm) infection by epigenetically promoting il-12 expression independent of its carbonic anhydrase activity. deficiency of car6-b attenu ...201728739930
listeria monocytogenes in raw milk, milking equipment and dairy workers: molecular characterization and antimicrobial resistance patterns.the aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst l. monocytogenes isolated from raw milk, milking equipment, and hand swabs from workers in dairy farms.201728739228
listeria monocytogenes cytosolic metabolism promotes replication, survival, and evasion of innate immunity.listeria monocytogenes, the causative agent of listeriosis, is an intracellular pathogen that is exquisitely evolved to survive and replicate in the cytosol of eukaryotic cells. eukaryotic cells typically restrict bacteria from colonising the cytosol, likely through a combination of cell autonomous defences, nutritional immunity, and innate immune responses including induction of programmed cell death. this suggests that l. monocytogenes and other professional cytosolic pathogens possess unique ...201728656691
listeria placental infection.the gram-positive facultative intracellular bacterium listeria monocytogenes is the causative agent of listeriosis, a severe food-borne infection. pregnant women are at risk of contracting listeriosis, which can potentially lead to miscarriage, stillbirth, preterm birth, and congenital neonatal infections. while other systemic bacterial infections may result in adverse pregnancy outcomes at comparable frequencies, l. monocytogenes has particular notoriety because fetal complications largely occu ...201728655824
hepcidin-(in)dependent mechanisms of iron metabolism regulation during infection by listeria and salmonella.during bacterial infection, the pathogenic agent and the host battle for iron, due to its importance for fundamental cellular processes. however, iron redistribution and sequestration during infection can culminate in anemia. although hepcidin has been recognized as the key regulator of iron metabolism, in some infections its levels remain unaffected, suggesting the involvement of other players in iron metabolism deregulation. in this work, we use a mouse model to elucidate the main cellular and ...201728652306
an improve protocol for pcr using lm1 and lm2 primers for listeria monocytogenes detection in food matrices.several studies have observed that a conventional pcr protocol using primers lm1 and lm2 for the identification of gene hlya listeria monocytogenes generates non-specific pcr amplifications and false positives. for this reason in this study, we provide a modified pcr protocol that improves the specificity of the lm1 and lm2 primers.201728735310
early trigeminal nerve involvement in listeria monocytogenes rhombencephalitis: case series and systematic review.listeria monocytogenes is associated with rhombencephalitis. however, the exact mechanisms of brainstem invasion remains poorly understood. here, we demonstrate clinical and radiological data suggesting that listeria may invade the brainstem via the trigeminal nerve. three females (41, 64 and 70 years) with culture proven l. monocytogenes bacteremia and rhombencephalitis were investigated in the period of 2014-16. t2-weighted and contrast-enhanced t1-weighted mri revealed a cerebellopontine absc ...201728730571
genome sequences of two listeria monocytogenes strains from nectarines associated with listeriosis in 2014.listeria monocytogenes is an important foodborne pathogen. here, we present the annotated whole genome of listeria monocytogenes strains f14m01297-c2 and f14m01297-c4, isolated from nectarines distributed by a packing facility in california during an investigation of listeriosis associated with stone fruit in 2014.201728729255
antimicrobial effect of black pepper petroleum ether extract for the morphology of listeria monocytogenes and salmonella typhimurium.this study aimed to evaluate the effects of black pepper petroleum extract (bppe) on pathogenic bacteria. the extraction from black pepper showed intense antimicrobial activity against the gram-positive listeria monocytogenes atcc 19115 and the gram-negative bacteria salmonella typhimurium atcc 14028. the minimum inhibitory concentrations of bppe against l. monocytogenes and s. typhimurium were 0.625 and 1.25 mg/ml, respectively. detection of alkaline phosphatase outside the cell revealed that b ...201728720964
inactivation of heat adapted and chlorine adapted listeria monocytogenes atcc 7644 on tomatoes using sodium dodecyl sulphate, levulinic acid and sodium hypochlorite solution.the effectiveness of sodium dodecyl sulphate (sds), sodium hypochlorite solution and levulinic acid in reducing the survival of heat adapted and chlorine adapted listeria monocytogenes atcc 7644 was evaluated. the results against heat adapted l. monocytognes revealed that sodium hypochlorite solution was the least effective, achieving log reduction of 2.75, 2.94 and 3.97 log colony forming unit (cfu)/ml for 1, 3 and 5 minutes, respectively. sds was able to achieve 8 log reduction for both heat a ...201728713785
[listeriosis of central nervous system in patients with ulcerative colitis - case study].in the recently an increase morbidity inflammatory bowel disease, including ulcerative colitis was observed. the use of purine analogs and their metabolites are associated with a higher incidence of infections in this group of patients. listeriosis is an infectious disease caused by a relatively anaerobic gram-positive bacteria - listeria monocytogenes. common symptoms include fever, nausea, vomiting and diarrhea, but these pathogens can also cause myocarditis, central nervous system infections, ...201728713103
listeria monocytogenes pdee, a phosphodiesterase that contributes to virulence and has hydrolytic activity against cyclic mononucleotides and cyclic dinucleotides.we have identified and partially characterized a putative hd domain hydrolase, lmof2365_2464, which is highly expressed during listerial intracellular replication. lmof2365_2464 is annotated as a putative hd domain-containing hydrolase. the ability of an isogenic mutant strain, f2365δ2464, to adhere, invade and replicate in intestinal epithelial cells (caco-2) was significantly lower than parent strain f2365. colonization of mouse liver and spleen by l. monocytogenes f2365 was significantly high ...201728711509
crmp-1 enhances evl-mediated actin elongation to build lamellipodia and the actin cortex.cells can control actin polymerization by nucleating new filaments or elongating existing ones. we recently identified crmp-1 as a factor that stimulates the formation of listeria monocytogenes actin comet tails, thereby implicating it in actin assembly. we now show that crmp-1 is a major contributor to actin assembly in epithelial cells, where it works with the ena/vasp family member evl to assemble the actin cytoskeleton in the apical cortex and in protruding lamellipodia. crmp-1 and evl bind ...201728630144
listeria-vectored vaccine expressing the mycobacterium tuberculosis 30 kda major secretory protein via the constitutively active prfa* regulon boosts bcg efficacy against tuberculosis.a potent vaccine against tuberculosis, one of the world's deadliest diseases, is needed to enhance the immunity of people worldwide, most of whom have been vaccinated with the partially effective bcg vaccine. here we investigate novel live attenuated recombinant listeria monocytogenes (rlm) vaccines expressing the mycobacterium tuberculosis (mtb) 30 kda major secretory protein (r30/ag85b) (rlm30) as heterologous booster vaccines in animals primed with bcg. using three attenuated lm vectors, rlm ...201728630063
variations in biofilm formation, desiccation resistance and benzalkonium chloride susceptibility among listeria monocytogenes strains isolated in canada.listeria monocytogenes is a pathogenic foodborne microorganism noted for its ability to survive in the environment and food processing facilities. survival may be related to the phenotype of individual strains including the ability to form biofilms and resist desiccation and/or sanitizer exposure. the objectives of this research were to compare 14 l. monocytogenes strains isolated from blood (3), food (6) and water (5) with respect to their benzalkonium chloride (bac) sensitivity, desiccation re ...201728710947
hyperinvasiveness and increased intercellular spread of listeria monocytogenes sequence type 1 are independent of listeriolysin s, internalin f and internalin j1.listeria monocytogenes is a genetically heterogeneous species, which is divided into evolutionary lineages and clonal complexes (ccs). not all l. monocytogenes isolates are equally likely to cause disease, with cc1, and in particular sequence type (st) 1, being the most prevalent complex in human and ruminant infections and more specifically in neurolisteriosis. while the major factors that determine neurotropism are unknown, the l. monocytogenes cc1 strains harbour listeriolysin s (lls) and par ...201728708050
growth kinetics of listeria monocytogenes in cut produce.cut produce continues to constitute a significant portion of the fresh fruit and vegetables sold directly to consumers. as such, the safety of these items during storage, handling, and display remains a concern. cut tomatoes, cut leafy greens, and cut melons, which have been studied in relation to their ability to support pathogen growth, have been specifically identified as needing temperature control for safety. data are needed on the growth behavior of foodborne pathogens in other types of cu ...201728708030
whole genome sequencing analyses of listeria monocytogenes that persisted in a milkshake machine for a year and caused illnesses in washington state.in 2015, in addition to a united states multistate outbreak linked to contaminated ice cream, another outbreak linked to ice cream was reported in the pacific northwest of the united states. it was a hospital-acquired outbreak linked to milkshakes, made from contaminated ice cream mixes and milkshake maker, served to patients. here we performed multiple analyses on isolates associated with this outbreak: pulsed-field gel electrophoresis (pfge), whole genome single nucleotide polymorphism (snp) a ...201728619007
development of biopolymer composite films using a microfluidization technique for carboxymethylcellulose and apple skin particles.biopolymer films based on apple skin powder (asp) and carboxymethylcellulose (cmc) were developed with the addition of apple skin extract (ase) and tartaric acid (ta). asp/cmc composite films were prepared by mixing cmc with asp solution using a microfluidization technique to reduce particle size. then, various concentrations of ase and ta were incorporated into the film solution as an antioxidant and an antimicrobial agent, respectively. fourier transform infrared (ftir), optical, mechanical, w ...201728617325
influence of food characteristics and food additives on the antimicrobial effect of garlic and oregano essential oils.utilization of essential oils (eos) as antimicrobial agents against foodborne disease has gained importance, for their use as natural preservatives. since potential interactions between eos and food characteristics may affect their antimicrobial properties, the present work studies the influence of fat, protein, ph, aw and food additives on the antimicrobial effect of oregano and garlic eos against salmonella spp. and listeria monocytogenes. results showed that protein, ph, aw, presence of beef ...201728604598
sglt1 deficiency turns listeria infection into a lethal disease in mice.cellular glucose uptake may involve either non-concentrative glucose carriers of the glut family or na+-coupled glucose-carrier sglt1, which accumulates glucose against glucose gradients and may thus accomplish cellular glucose uptake even at dramatically decreased extracellular glucose concentrations. sglt1 is not only expressed in epithelia but as well in tumour cells and immune cells. immune cell functions strongly depend on their metabolism, therefore we hypothesized that deficiency of sglt1 ...201728704812
thioredoxin a is essential for motility and contributes to host infection of listeria monocytogenes via redox interactions.microbes employ the thioredoxin system to defend against oxidative stress and ensure correct disulfide bonding to maintain protein function. listeria monocytogenes has been shown to encode a putative thioredoxin, trxa, but its biological roles and underlying mechanisms remain unknown. here, we showed that expression of l. monocytogenes trxa is significantly induced in bacteria treated with the thiol-specific oxidizing agent, diamide. deletion of trxa markedly compromised tolerance of the pathoge ...201728702378
synergistic antimicrobial combinations inhibit and inactivate listeria monocytogenes in neutral and acidic broth systems.the use of antimicrobial compounds can be an effective approach to control listeria monocytogenes in ready-to-eat foods, but it can also be limited by cost, restrictions on concentrations in foods, and potential changes to organoleptic properties. combinatorial approaches that produce additive or synergistic effects allow for reductions in individual antimicrobial concentrations while achieving the same level of control. the present study determined the mic and mbc of an antimicrobial compound w ...201728691884
molecular docking based screening of listeriolysin-o for improved inhibitors.listeriolysine-o (llo) is a 50kda protein responsible for listeria monocytogenes pathogenicity. the structure of llo (pdb id: 4cdb) with domains d1 to d4 is known. therefore, it is of interest to identify conserved regions among llo variants for destabilizing oligomerization (50 mer complex) of its monomers using appropriate inhibitors. therefore, it is of interest to identify suitable inhibitors for inhibiting llo. previous reports suggest the use of flavanoids like compounds for inhibiting llo ...201728690383
fast detection of listeria monocytogenes through a nanohybrid quantum dot complex.listeria monocytogenes is a recognized foodborne pathogen that causes listeriosis in susceptible consumers. currently, the detection systems for listeria in food detect live and dead bacteria, being the viable microorganisms most relevant for their ability to cause sickness in the population at risk. for this reason, a new nanohybrid compound was developed for the optical detection of listeria that was based on polyamidoamine dendrimers functionalized with an auxotrophic cofactor (lipoic acid), ...201728689324
a cysteine protease (cathepsin z) from disk abalone, haliotis discus discus: genomic characterization and transcriptional profiling during bacterial infections.cathepsin z (ctsz) is lysosomal cysteine protease of the papain superfamily. it participates in the host immune defense via phagocytosis, signal transduction, cell-cell communication, proliferation, and migration of immune cells such as monocytes, macrophages, and dendritic cells. hence, ctsz is also acknowledged as an acute-phase protein in host immunity. in this study, we sought to identify the ctsz homolog from disk abalone (abctsz) and characterize it at the molecular, genomic, and transcrip ...201728687334
internalization of listeria monocytogenes in cantaloupes during dump tank washing and hydrocooling.recent listeriosis outbreaks and recalls associated with cantaloupes urge for studies to understand the mechanisms of cantaloupe contamination by listeria monocytogenes. postharvest practices such as washing and hydrocooling were suggested to facilitate the contamination of fresh fruits by human pathogens. this study assessed the potential of l. monocytogenes internalization into cantaloupes during dump tank washing and immersion-type hydrocooling in water contaminated with l. monocytogenes. the ...201728667935
cleaning and disinfection of biofilms composed of listeria monocytogenes and background microbiota from meat processing surfaces.surfaces of food processing premises are exposed to regular cleaning and disinfection (c&d) regimes, using biocides that are highly effective against bacteria growing as planktonic cells. however, bacteria growing in surface associated communities (biofilms) are typically more tolerant towards c&d than their individual free cells counterparts, and survival of pathogens such as listeria monocytogenes may be affected by interspecies interactions within biofilms. in this study, pseudomonas and acin ...201728667108
tracking of listeria monocytogenes in meat establishment using whole genome sequencing as a food safety management tool: a proof of concept.repeated listeria outbreaks particularly associated with ready-to-eat (rte) delicatessen meat products have been reported annually at global level. the most frequent scenario that led to foodborne outbreaks was the post-thermal treatment cross-contamination of deli meat products during slicing and modified atmosphere packaging (map). the precondition for such cross contamination is the previous introduction of listeria into meat processing facilities and subsequent colonization of the production ...201728666130
strand specific rna-sequencing and membrane lipid profiling reveals growth phase-dependent cold stress response mechanisms in listeria monocytogenes.the human pathogen listeria monocytogenes continues to pose a challenge in the food industry, where it is known to contaminate ready-to-eat foods and grow during refrigerated storage. increased knowledge of the cold-stress response of this pathogen will enhance the ability to control it in the food-supply-chain. this study utilized strand-specific rna sequencing and whole cell fatty acid (fa) profiling to characterize the bacterium's cold stress response. rna and fas were extracted from a cold-t ...201728662112
biopreservative efficacy of bacteriocin bacfl31 in raw ground turkey meat in terms of microbiological, physicochemical, and sensory qualities.the effect of the semi purified bacteriocin bacfl31 at 200 and 400 au/g on the shelf life of refrigerated raw ground turkey meat was investigated. the microbiological, physicochemical, and sensory properties of the meat samples were examined during refrigerated storage. the findings indicated that bacfl31 treatments were effective (p<0.05) against the proliferation of various spoilage microorganisms and suppressed the growth of listeria monocytogenes and salmonella typhimurium. the ph, % met-mb, ...201728659558
physiological and molecular understanding of bacterial polysaccharide monooxygenases.bacteria have long been known to secrete enzymes that degrade cellulose and chitin. the degradation of these two polymers predominantly involves two enzyme families that work synergistically with one another: glycoside hydrolases (ghs) and polysaccharide monooxygenases (pmos). although bacterial pmos are a relatively recent addition to the known biopolymer degradation machinery, there is an extensive amount of literature implicating pmo in numerous physiological roles. this review focuses on the ...201728659491
lanosterol modulates tlr4-mediated innate immune responses in macrophages.macrophages perform critical functions in both innate immunity and cholesterol metabolism. here, we report that activation of toll-like receptor 4 (tlr4) in macrophages causes lanosterol, the first sterol intermediate in the cholesterol biosynthetic pathway, to accumulate. this effect is due to type i interferon (ifn)-dependent histone deacetylase 1 (hdac1) transcriptional repression of lanosterol-14α-demethylase, the gene product of cyp51a1. lanosterol accumulation in macrophages, because of ei ...201728658622
e3 ubiquitin ligase znrf4 negatively regulates nod2 signalling and induces tolerance to mdp.optimal regulation of the innate immune receptor nucleotide-binding oligomerization domain-containing protein 2 (nod2) is essential for controlling bacterial infections and inflammatory disorders. chronic nod2 stimulation induces non-responsiveness to restimulation, termed nod2-induced tolerance. although the levels of the nod2 adaptor, rip2, are reported to regulate both acute and chronic nod2 signalling, how rip2 levels are modulated is unclear. here we show that znrf4 induces k48-linked ubiqu ...201728656966
a nationwide outbreak of listeriosis associated with cold-cuts, sweden 2013-2014.in january 2014, the public health agency of sweden noticed an increase in listeriosis cases. isolates from 10 cases had identical pulsed field gel electrophoresis (pfge) profiles, suggesting a common source. we investigated the outbreak to identify the source and stop transmission. we looked for cases in 2013-2014 and also compared cases notified after february 2014 to randomly selected controls. we surveyed food items consumed two weeks prior to symptom onset. listeria monocytogenes isolates f ...201728649304
real-time whole-genome sequencing for surveillance of listeria monocytogenes, france.during 2015-2016, we evaluated the performance of whole-genome sequencing (wgs) as a routine typing tool. its added value for microbiological and epidemiologic surveillance of listeriosis was compared with that for pulsed-field gel electrophoresis (pfge), the current standard method. a total of 2,743 listeria monocytogenes isolates collected as part of routine surveillance were characterized in parallel by pfge and core genome multilocus sequence typing (cgmlst) extracted from wgs. we investigat ...201728643628
antibacterial efficacy of nisin, bacteriophage p100 and sodium lactate against listeria monocytogenes in ready-to-eat sliced pork ham.the effectiveness of bacteriophage p100, nisin and sodium lactate, individually and in combination, in inhibiting listeria monocytogenes in ready-to-eat pork ham slices was assessed. the antimicrobials were applied to the surfaces of ready-to-eat pork ham slices, which were inoculated with a mixture of l. monocytogenes. among the individual antimicrobial treatments, bacteriophage p100 was the most effective, decreasing l. monocytogenes to undetectable levels at zero and 72h post-infection. sodiu ...201728641956
core-shell pla-pva porous microparticles as carriers for bacteriocin nisin.this work is focused on preparation of novel porous type of core-shell-structured microparticles based on polylactide (shell) and poly(vinyl alcohol) cross-linked with glutaric acid (ga) (core) prepared by water-in-oil-in-water solvent evaporation technique. the microparticle systems were used as delivery systems for immobilisation of model antibacterial agent - nisin. the effect of cross-linking and the initial amount of nisin on their morphology was investigated using scanning electron microsc ...201728635414
influence of lactic acid and post-treatment recovery time on the heat resistance of listeria monocytogenes.the aim of this study was to evaluate the effect of lactic acid (la) with and without organic material at various post-treatment recovery times on the heat resistance of listeria monocytogenes (lm). la decreased lm numbers; however, the effect was remarkably attenuated by the presence of organic matter. five strains of lm were treated with la and the listericidal effects were compared. the effect of la varied depending on the strain, with ≥3.0% (w/w) la required to kill the lm strains in a short ...201728633051
changing us population demographics: what does this mean for listeriosis incidence and exposure?listeria monocytogenes is an important cause of foodborne illness hospitalization, fetal loss, and death in the united states. listeriosis incidence rate varies significantly among population subgroups with pregnant women, older persons, and the hispanic population having increased relative risks compared with the other subpopulations. using estimated rates of listeriosis per subpopulation based on foodnet data from 2004 to 2009, we evaluate the expected number of cases and incidence rates of li ...201728632414
listeria monocytogenes bacteraemia over an 11-year period: clinical and epidemiologic characteristics in the south area of madrid. 201728527675
effects of parsley extract powder as an alternative for the direct addition of sodium nitrite in the production of mortadella-type sausages - impact on microbiological, physicochemical and sensory aspects.increasing concern about chemical additives in processed meat has led to an increased market of uncured and alternatively cured meat products. however, the use of vegetable extracts or the exclusion of curing salt may increase the risk of greater bacterial growth and alteration of several physicochemical parameters. therefore, in this study mortadella-type sausages, manufactured with 1.07 (v3), 2.14 (v4) and 4.29 (v5) g parsley extract powder/kg sausage meat were produced. these sausage variants ...201728527368
a novel role of listeria monocytogenes membrane vesicles in inhibition of autophagy and cell death.bacterial membrane vesicle (mv) production has been mainly studied in gram-negative species. in this study, we show that listeria monocytogenes, a gram-positive pathogen that causes the food-borne illness listeriosis, produces mvs both in vitro and in vivo. we found that a major virulence factor, the pore-forming hemolysin listeriolysin o (llo), is tightly associated with the mvs, where it resides in an oxidized, inactive state. previous studies have shown that llo may induce cell death and auto ...201728516064
listeriolysin o: from bazooka to swiss army knife.listeria monocytogenes (lm) is a gram-positive facultative intracellular pathogen. infections in humans can lead to listeriosis, a systemic disease with a high mortality rate. one important mechanism of lm dissemination involves cell-to-cell spread after bacteria have entered the cytosol of host cells. listeriolysin o (llo; encoded by the hly gene) is a virulence factor present in lm that plays a central role in the cell-to-cell spread process. llo is a member of the cholesterol-dependent cytoly ...201728630160
prevalence and serotype distribution of listeria monocytogenes isolated from foods in montevideo-uruguay.the aim of this work was to study the prevalence of listeria monocytogenes in foods obtained in retail shops and food industries located in montevideo-uruguay, and to identify the serogroups of the obtained isolates. three-thousand one-hundred and seventy-five food samples (frozen, deli meats, ready-to-eat and cheese) were analyzed. the obtained isolates were serogrouped by multiplex pcr and serotyped by conventional procedure. genetic comparisons were performed using pulsed-field gel electropho ...201728629969
a multiplex rt-pcr assay for s. aureus, l. monocytogenes, and salmonella spp. detection in raw milk with pre-enrichment.this study firstly developed a multiplex real-time pcr (rt-pcr) technique combined with a pre-enrichment step to simultaneously detect staphylococcus aureus (s. aureus), listeria monocytogenes (l. monocytogenes) and salmonella spp. in raw milk and the dairy farm environment (feces, soil, feed, water) in one reaction. brain heart infusion (bhi) broth was selected for the enrichment step to increase the density of the target bacteria by using an incubation of 4 h before multiplex rt-pcr. the resul ...201728620364
full-genome sequence of listeria monocytogenes strain h34, isolated from a newborn with sepsis in uruguay.the foodborne pathogen listeria monocytogenes causes severe disease mainly in the vulnerable populations of the young, old, pregnant, and immunocompromised. here, we present the genome sequence of l. monocytogenes h34, a serotype 1/2b, lineage i, sequence type 489 (st489) strain, isolated from a neonatal sepsis case in uruguay.201728619811
how the study of listeria monocytogenes has led to new concepts in biology.the opportunistic intracellular bacterial pathogen listeria monocytogenes has in 30 years emerged as an exceptional bacterial model system in infection biology. research on this bacterium has provided considerable insight into how pathogenic bacteria adapt to mammalian hosts, invade eukaryotic cells, move intracellularly, interfere with host cell functions and disseminate within tissues. it also contributed to unveil features of normal host cell pathways and unsuspected functions of previously k ...201728604108
persistent listeria monocytogenes strains isolated from mussel production facilities form more biofilm but are not linked to specific genetic markers.contamination of mussels with the human pathogen listeria monocytogenes occurs during processing in the factory, possibly from bacteria persisting in the factory's indoor and outdoor areas. in this study, a selection of persistent (n=8) and sporadic (n=8) l. monocytogenes isolates associated with mussel-processing premises in new zealand were investigated for their phenotypic and genomic characteristics. to identify traits that favour or contribute to bacterial persistence, biofilm formation, he ...201728599174
comparison of the in vitro activity of ampicillin and moxifloxacin against listeria monocytogenes at achievable concentrations in the central nervous system.the aim of this study was to compare the in vitro activity of ampicillin and moxifloxacin against six isolates selected from 154 invasive clinical isolates of listeria monocytogenes and evaluate their intra- and extracellular activities with achievable central nervous system concentrations obtained using monte carlo simulations with conventional and unconventional dosages.201728598305
mathematical model of interaction between bacteriocin-producing lactic acid bacteria and listeria. part 1: steady states and thresholds.mathematical modeling is an important tool to assessing quantitative conjectures and to answer specific questions. in the modeling, we assume that a competitor represented by a lactic acid bacterium produces antimicrobial compounds (substances that kill microorganisms or inhibit their growth), such as lactic acid and bacteriocins, with some cost to its own growth. bacteriocins are protein compounds with antimicrobial effect against related species and bacteria such as listeria monocytogenes, whi ...201728597170
genome sequences of listeria monocytogenes strains with resistance to arsenic.listeria monocytogenes frequently exhibits resistance to arsenic. we report here the draft genome sequences of eight genetically diverse arsenic-resistant l. monocytogenes strains from human listeriosis and food-associated environments. the availability of these genomes will help elucidate the role of heavy-metal resistance in the ecology of l. monocytogenes.201728495780
complete genome sequences of 12 isolates of listeria monocytogenes belonging to serotypes 1/2a, 1/2b, and 4b obtained from food products and food-processing environments in canada.listeria monocytogenes is the etiological agent for an often fatal foodborne illness known as listeriosis. here, we present the complete genome sequences of 12 l. monocytogenes isolates representing the three most common serotypes of this pathogen (1/2a, 1/2b, and 4b), collected in canada from different food products and environmental sources.201728495767
draft genome sequences of 25 listeria monocytogenes isolates associated with human clinical listeriosis in ireland.listeria monocytogenes is a gram-positive opportunistic pathogen that is the causative agent of listeriosis. here, we report the draft genome sequences of 25 l. monocytogenes strains isolated from patients with clinical listeriosis in the republic of ireland between 2013 and 2015.201728495762
inhibition strategies of listeria monocytogenes biofilms-current knowledge and future outlooks.there is an increasing trend in the food industry on the listeria monocytogenes biofilm formation and inhibition. this is attributed to its easy survival on contact surfaces, resistance to disinfectants or antibiotics and growth under the stringent condition used for food processing and preservation thereby leading to food contamination products by direct or indirect exposure. though, there is a lack of conclusive evidences about the mechanism of biofilm formation, in this review, the concept of ...201728594071
commensal microbes provide first line defense against listeria monocytogenes infection.listeria monocytogenes is a foodborne pathogen that causes septicemia, meningitis and chorioamnionitis and is associated with high mortality. immunocompetent humans and animals, however, can tolerate high doses of l. monocytogenes without developing systemic disease. the intestinal microbiota provides colonization resistance against many orally acquired pathogens, and antibiotic-mediated depletion of the microbiota reduces host resistance to infection. here we show that a diverse microbiota mark ...201728588016
longitudinal monitoring of listeria monocytogenes and listeria phages in seafood processing environments in thailand.listeria monocytogenes is a foodborne pathogen commonly found in environments of seafood processing, thus presenting a challenge for eradication from seafood processing facilities. monitoring the prevalence and subtype diversity of l. monocytogenes together with phages that are specific to listeria spp. ("listeria phages") will provide knowledge on the bacteria-phage ecology in food processing plants. in this work, a total of 595 samples were collected from raw material, finished seafood product ...201728576358
empiric listeria monocytogenes antibiotic coverage for febrile infants (age, 0-90 days). 201728574538
genome-wide-analyses of listeria monocytogenes from food-processing plants reveal clonal diversity and date the emergence of persisting sequence types.whole genome sequencing is increasing used in epidemiology, e.g. for tracing outbreaks of food-borne diseases. this requires in-depth understanding of pathogen emergence, persistence and genomic diversity along the food production chain including in food processing plants. we sequenced the genomes of 80 isolates of listeria monocytogenes sampled from danish food processing plants over a time-period of 20 years, and analysed the sequences together with 10 public available reference genomes to adv ...201728574206
draft genome sequences of listeria monocytogenes, isolated from fresh leaf vegetables in owerri city, nigeria.here, we report the draft genome sequences of three listeria monocytogenes isolates from fresh leaves collected in nigeria, belonging to sequence types st5 and st155 (sublineages sl5 and sl155, respectively).201728572306
curcumin promotes the clearance of listeria monocytogenes both in vitro and in vivo by reducing listeriolysin o oligomers.the pore-forming toxin listeriolysin o (llo), an essential virulence factor that is secreted by listeria monocytogenes (l. monocytogenes), is responsible for bacterial breaching at the phagosomal membranes and subsequent release into the cytoplasm; it cannot be recognized by the host immune system. the vital role that llo plays in bacterial pathogenicity and evading host immune clearance makes this virulence a promising target for addressing l. monocytogenes infection. in this study, we hypothes ...201728567044
impact of nutrient restriction on the structure of listeria monocytogenes biofilm grown in a microfluidic system.biofilm formation by the pathogen listeria monocytogenes is a major concern in food industries. the aim of this work was to elucidate the effect of nutrient limitation on both biofilm architecture and on the viability of the bacteria in microfluidic growth conditions. biofilm formation by two l. monocytogenes strains was performed in a rich medium (bhi) and in a 10-fold diluted bhi (bhi/10) at 30°c for 24 h by using both static conditions and the microfluidic system bioflux. in dynamic condition ...201728567031
naïve helper t cells with high cd5 expression have increased calcium signaling.the adaptive immune response is orchestrated by t helper cells and their function is dependent upon interactions between the t cell receptor (tcr), peptide mhc (pmhc) and co-receptors. tcr-pmhc interactions initiate calcium signaling cascades which determine t cell activation, survival, proliferation and differentiation. cd5 is a co-receptor that plays an important role in regulating t cell signaling and fate during thymocyte education. cd5 surface expression on mature single positive thymocytes ...201728562659
deciphering the landscape of host barriers to listeria monocytogenes infection.listeria monocytogenes is a common food-borne pathogen that can disseminate from the intestine and infect multiple organs. here, we used sequence tag-based analysis of microbial populations (stamp) to investigate lmonocytogenes population dynamics during infection. we created a genetically barcoded library of murinized lmonocytogenes and then used deep sequencing to track the pathogen's dissemination routes and quantify its founding population (nb) sizes in different organs. we found that the pa ...201728559314
whole genome and core genome multilocus sequence typing and single nucleotide polymorphism analyses of listeria monocytogenes associated with an outbreak linked to cheese, united states, 2013.epidemiological findings of a listeriosis outbreak in 2013 implicated hispanic-style cheese produced by company a, and pulsed-field gel electrophoresis (pfge) and whole genome sequencing (wgs) were performed on clinical isolates and representative isolates collected from company a cheese and environmental samples during the investigation. the results strengthened the evidence for cheese as the vehicle. surveillance sampling and wgs three months later revealed that the equipment purchased by comp ...201728550058
erratum: uncovering listeria monocytogenes hypervirulence by harnessing its biodiversity. 201728546578
the absence of tnf permits myeloid arginase 1 expression in experimental l. monocytogenes infection.during an immune response inflammatory macrophages with their wide variety of effector mechanisms including the expression of inducible nitric oxide synthase play an important part in the defense against invading pathogens. the inflammatory phenotype requires the presence of tnf which suppresses alternative activation. in the bacterial listeria monocytogenes infection model inflammatory macrophages are crucial for protection. after infection, tnf-deficient hosts have a similar number of splenic ...201728545808
down regulation of macrophage ifngr1 exacerbates systemic l. monocytogenes infection.interferons (ifns) target macrophages to regulate inflammation and resistance to microbial infections. the type ii ifn (ifnγ) acts on a cell surface receptor (ifngr) to promote gene expression that enhance macrophage inflammatory and anti-microbial activity. type i ifns can dampen macrophage responsiveness to ifnγ and are associated with increased susceptibility to numerous bacterial infections. the precise mechanisms responsible for these effects remain unclear. type i ifns silence macrophage i ...201728542482
invasive listeria monocytogenes gastroenteritis leading to stupor, bacteremia, fever, and diarrhea: a rare life-threatening condition.listeria monocytogenes is a gram-positive, rod-shaped organism that can cause serious infections such as meningitis, invasive gastroenteritis, and endocarditis. every year 1600 people in the united states are affected, with significant mortality of 260 people annually. listeria gastroenteritis has the third highest mortality rate among all the food-borne infection. invasive listeriosis most commonly affect pregnant women, those in extremes of ages, people with comorbid diseases, and people with ...201728540315
listeriosis during pregnancy.listeriosis is a rare foodborne illness caused by listeria monocytogenes. it can be transmitted by consuming contaminated ready-to-eat food, long shelf-life products, deli meats, and soft cheeses. listeria has a predilection to affect immunocompromised patients, elderly people, pregnant women and neonates. in particular, pregnant women are at ~18 times greater risk of infection than general population due to specific pregnancy-related suppressed cell-mediated immunity and placental tropism of l. ...201728536811
insights into clpxp proteolysis: heterooligomerization and partial deactivation enhance chaperone affinity and substrate turnover in listeria monocytogenes.caseinolytic proteases (clpp) are important for recognition and controlled degradation of damaged proteins. while the majority of bacterial organisms utilize only a single clpp, listeria monocytogenes expresses two isoforms (lmclpp1 and lmclpp2). lmclpps assemble into either a lmclpp2 homocomplex or a lmclpp1/2 heterooligomeric complex. the heterocomplex in association with the chaperone clpx, exhibits a boost in proteolytic activity for unknown reasons. here, we use a combined chemical and bioc ...201728451288
structural basis of crispr-spycas9 inhibition by an anti-crispr protein.crispr-cas9 systems are bacterial adaptive immune systems that defend against infection by phages. through the rna-guided endonuclease activity of cas9 they degrade double-stranded dna with a protospacer adjacent motif (pam) and sequences complementary to the guide rna. recently, two anti-crispr proteins (acriia2 and acriia4 from listeria monocytogenes prophages) were identified, both of which inhibit streptococcus pyogenes cas9 (spycas9) and l. monocytogenes cas9 activity in bacteria and human ...201728448066
isolation and characterization of listeria phages for control of growth of listeria monocytogenes in milk.in this study, two listeria bacteriophages, lmp1 and lmp7, were isolated from chicken feces as a means of biocontrol of l. monocytogenes. both bacteriophages had a lytic effect on l. monocytogenes atcc 7644, 15313, 19114, and 19115. phages lmp1 and lmp7 were able to inhibit the growth of l. monocytogenes atcc 7644 and 19114 in tryptic soy broth at 10°c and 30°c. nevertheless, lmp1 was more effective than lmp7 at inhibiting l. monocytogenes atcc 19114. on the contrary, lmp7 was more effective tha ...201728515656
assessment of microbial and radioactive contaminations in korean cold duck meats and electron-beam application for quality improvement.animal-origin food products pose serious threat to public food safety due to high microbial loads. the microbial and radioactive contaminations in commercial cold duck meat products were evaluated. ten different lots of commercial samples (c1-c10) were classified based on type and smoking process. all samples were highly contaminated (< 4-7 log cfu/g) with total aerobic bacteria (tab), yeasts and molds (y&m), and 7 samples (c1-c7) were positive for coliforms. furthermore, three samples were cont ...201728515653
unusual listeria monocytogenes peritonitis in peritoneal dialysis patient with liver cirrhosis: a case report and review of literature.spontaneous listeria peritonitis is well described in liver failure, but is uncommon in peritoneal dialysis patients. atypical cases where peritonitis symptoms develop after systemic manifestations are rare and challenging for diagnostic. a 57-year-old peritoneal dialysis patient with history of ethylic cirrhosis was admitted after epileptic seizure. on admission, patient was soporous without signs of peritonitis and meningitis. patient's peritoneal effluent was clear, with normal leukocytes. cr ...201728509139
tetr-dependent gene regulation in intracellular listeria monocytogenes demonstrates the spatiotemporal surface distribution of acta.to enable specific and tightly controlled gene expression both in vitro and during the intracellular lifecycle of the pathogen listeria monocytogenes, a tetr-dependent genetic induction system was developed. highest concentration of cytoplasmic tetr and best repression of teto-controlled genes was obtained by tetr expression from the synthetic promoter pt17 . anhydrotetracycline (atc) as inducer permitted concentration-dependent, fine-tuned expression of genes under control of the teto operator ...201728508453
limited colonization undermined by inadequate early immune responses defines the dynamics of decidual listeriosis.the bacterial pathogen listeria monocytogenes causes foodborne systemic disease in pregnant women, which can lead to preterm labor, stillbirth, or severe neonatal disease. colonization of the maternal decidua appears to be an initial step in the maternal component of the disease as well as bacterial transmission to the placenta and fetus. host-pathogen interactions in the decidua during this early stage of infection remain poorly understood. here, we assessed the dynamics of l. monocytogenes inf ...201728507070
spontaneous bacterial peritonitis due to listeria monocytogenes: always to be remembered. 201728502590
identification of a major listeria monocytogenes outbreak clone linked to soft cheese in northern italy - 2009-2011.molecular subtyping and enhanced surveillance in lombardy region identified a cluster of possibly related listeriosis cases from 2006 to 2010. this cluster grouped 31 isolates that belonged to serotype 1/2a and sequence type 38 (st38) as defined by multilocus sequence typing (mlst).201728499357
mtorc1 regulates mannose-6-phosphate receptor transport and t-cell vulnerability to regulatory t cells by controlling kinesin kif13a.mannose-6-phosphate receptor (m6pr) that facilitates cellular uptake of m6p-bearing proteins, including serine-protease granzyme-b (gzm-b) has an important role in t-cell activation, migration and contraction. however, molecular mechanisms controlling m6pr expression in t cells remain poorly understood. here, we show that m6pr expression on t cells is distinctively controlled by two common γ-chain cytokines interleukin-2 (il-2) and il-7, and the differential m6pr expression is not caused by an a ...201728496990
listeria endocarditis: a diagnostic challenge.a 74-year-old hemodialysis patient with a history of an atrial septum defect closure, coronary bypass surgery, and a st. jude aortic prosthetic valve was diagnosed with pneumonia and volume overload. blood cultures were positive for listeria monocytogenes, and amoxicillin was given for 2 weeks. immediately after discontinuation of amoxicillin, fever relapsed. transthoracic and transesophageal echocardiography showed no sign of endocarditis. given the fever relapse and 3 positive minor duke crite ...201728491879
comparative diagnostic efficacy of recombinant llo and pi-plc-based elisas for detection of listeriosis in animals.the present study for the first time evaluates the serodiagnostic efficacy of two recombinant antigens namely, listeriolysin o (rllo) and phosphatidyl-inositol phospholipase c (rpi-plc). indirect elisa with the above recombinant antigens was used on samples collected from bovines (n=106), goats (n=138) and pigs (n=92) having either a history of abortion, emaciation and/or apparently healthy animals. isolation of listeria was attempted from the blood samples using usda-fsis method. on screening o ...201728411150
characteristics and outcome of spontaneous bacterial meningitis in patients with cancer compared to patients without cancer.in cancer patients, who are frequently immunocompromised, bacterial meningitis (bm) can be a severe complication, with a different presentation, etiology, and course, compared to patients without cancer. our objective is to compare the characteristics and outcomes of bm in patients with and without cancer. a single-center, prospective observational cohort study, conducted between 1982 and 2012, in a tertiary university hospital in barcelona (spain). the main outcome measure is in-hospital mortal ...201728489800
analysis of listeria using exogenous volatile organic compound metabolites and their detection by static headspace-multi-capillary column-gas chromatography-ion mobility spectrometry (shs-mcc-gc-ims).listeria monocytogenes is a gram-positive bacterium and an opportunistic food-borne pathogen which poses significant risk to the immune-compromised and pregnant due to the increased likelihood of acquiring infection and potential transmission of infection to the unborn child. conventional methods of analysis suffer from either long turn-around times or lack the ability to discriminate between listeria spp. reliably. this paper investigates an alternative method of detecting listeria spp. using t ...201728484808
suppression of autoimmune demyelinating disease by preferential stimulation of cns-specific cd8 t cells using listeria-encoded neuroantigen.cd8 t-cells predominate in cns lesions of ms patients and display oligoclonal expansion. however, the role of myelin-specific cd8 t-cells in disease remains unclear, with studies showing protective and pathogenic roles in eae. we demonstrated a disease-suppressive function for cns-specific cd8 t-cells in a model where the antigen is exogenously administered in vivo and used for in vitro activation. to probe the nature of the cd8 response elicited by endogenously presented myelin antigens in vivo ...201728484224
label-free immuno-sensors for the fast detection of listeria in food.foodborne diseases are a major concern for both food industry and health organizations due to the economic costs and potential threats for human lives. for these reasons, specific regulations impose the research of pathogenic bacteria in food products. nevertheless, current methods, references and alternatives, take up to several days and require many handling steps. in order to improve pathogen detection in food, we developed an immune-sensor, based on surface plasmon resonance imaging (spri) a ...201728478556
a novel typing method for listeria monocytogenes using high-resolution melting analysis (hrma) of tandem repeat regions.listeria monocytogenes, which is responsible for causing food poisoning known as listeriosis, infects humans and animals. widely distributed in the environment, this bacterium is known to contaminate food products after being transmitted to factories via raw materials. to minimize the contamination of products by food pathogens, it is critical to identify and eliminate factory entry routes and pathways for the causative bacteria. high resolution melting analysis (hrma) is a method that takes adv ...201728475927
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