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the antimicrobial peptide aureocin a53 as an alternative agent for biopreservation of dairy products.the aim of this study was to investigate the potential of aureocin a53, a staphylococcal antimicrobial peptide, for improving food safety.201627225974
brain abscesses due to listeria monocytogenes after rituximab therapy. 201627219320
listeria monocytogenes septicemia in an immunocompromised dog.an 11-year-old, male castrated, boston terrier was presented to the north carolina state university college of veterinary medicine small animal emergency service with a 2-day history of progressive ataxia, left-sided head tilt, and anorexia. the dog had previously been diagnosed with chronic lymphoid leukemia and suspected immune-mediated destruction of his bone marrow precursor cells, possibly due to therapy with immunosuppressive dosages of prednisone and azathioprine. during the physical exam ...201627218230
purification of plasmodium sporozoites enhances parasite-specific cd8+ t cell responses.malaria infection caused by plasmodium parasites continues to cause enormous morbidity and mortality in areas where it is endemic, and there is no licensed vaccine capable of inducing sterile protection. hyperimmunization with attenuated whole sporozoites can induce sterile protective immune responses targeting preerythrocytic antigens. most animal models of hyperimmunization rely on sporozoites dissected from mosquito salivary glands and injected without further purification. in balb/c mice, re ...201627217420
inactivation of listeria monocytogenes, salmonella spp. and escherichia coli o157:h7 on cantaloupes by octenidine dihydrochloride.the efficacy of a new generation disinfectant, octenidine dihydrochloride (oh), as wash and coating treatments for reducing listeria monocytogenes (lm), salmonella spp. (sal), and escherichia coli o157:h7 (ec) on cantaloupe was investigated. cantaloupe rind plugs inoculated separately with the three bacterial species (∼8 log cfu/cm(2)) were washed for 1, 3, 5 min at 25 °c in water, or chlorine (200 ppm), ethanol (1%), oh (0.01, 0.05, 0.1%) and surviving populations were measured after treatment. ...201627217367
minimal inhibitory concentrations of undissociated lactic, acetic, citric and propionic acid for listeria monocytogenes under conditions relevant to cheese.minimal inhibitory concentrations (mics) of undissociated lactic acid were determined for six different listeria monocytogenes strains at 30 °c and in a ph range of 4.2-5.8. small increments in ph and acid concentrations were used to accurately establish the growth/no growth limits of l. monocytogenes for these acids. the mics of undissociated lactic acid in the ph range of 5.2-5.8 were generally higher than at ph 4.6 for the different l. monocytogenes strains. the average mic of undissociated l ...201627217360
validation of a predictive model coupling gas transfer and microbial growth in fresh food packed under modified atmosphere.predicting microbial safety of fresh products in modified atmosphere packaging implies to take into account the dynamic of o2, co2 and n2 exchanges in the system and its effect on microbial growth. in this paper a mechanistic model coupling gas transfer and predictive microbiology was validated using dedicated challenge-tests performed on poultry meat, fresh salmon and processed cheese, inoculated with either listeria monocytogenes or pseudomonas fluorescens and packed in commercially used packa ...201627217358
rna- and protein-mediated control of listeria monocytogenes virulence gene expression.the model opportunistic pathogen listeria monocytogenes has been the object of extensive research, aiming at understanding its ability to colonize diverse environmental niches and animal hosts. bacterial transcriptomes in various conditions reflect this efficient adaptability. we review here our current knowledge of the mechanisms allowing l. monocytogenes to respond to environmental changes and trigger pathogenicity, with a special focus on rna-mediated control of gene expression. we highlight ...201627217337
memory cd8(+) t cells require increased concentrations of acetate induced by stress for optimal function.how systemic metabolic alterations during acute infections impact immune cell function remains poorly understood. we found that acetate accumulates in the serum within hours of systemic bacterial infections and that these increased acetate concentrations are required for optimal memory cd8(+) t cell function in vitro and in vivo. mechanistically, upon uptake by memory cd8(+) t cells, stress levels of acetate expanded the cellular acetyl-coenzyme a pool via atp citrate lyase and promoted acetylat ...201627212436
shedding light on betl*: ppl2-lux mediated real-time analysis of betl* expression in listeria monocytogenes.we propose a mechanism of action for the betl* mutation which is based on dna topology. removing a single thymine residue from the betl σ(a) promoter's -10 and -35 spacer results in a 'twist'-mediated activation of transcription which accounts for the osmotolerance phenotype observed for strains expressing betl*.201627212260
detection, identification, and typing of listeria species from baled silages fed to dairy cows.anaerobiosis, critical for successful ensilage, constitutes a challenge in baled silages. the loss of complete anaerobiosis causes aerobic deterioration and silages undergo dry matter and nutrient losses, pathogen growth, and mycotoxin production. silage may represent an ideal substrate for listeria monocytogenes, a pathogen of primary concern in several cheeses. the aim of this research was to investigate the occurrence of listeria in baled silage fed to cows producing milk for a protected desi ...201627209131
loss of sigb in listeria monocytogenes strains egd-e and 10403s confers hyperresistance to hydrogen peroxide in stationary phase under aerobic conditions.sigb is the main stress gene regulator in listeria monocytogenes affecting the expression of more than 150 genes and thus contributing to multiple-stress resistance. despite its clear role in most stresses, its role in oxidative stress is uncertain, as results accompanying the loss of sigb range from hyperresistance to hypersensitivity. previously, these differences have been attributed to strain variation. in this study, we show conclusively that unlike for all other stresses, loss of sigb resu ...201627208116
potential impact of the resistance to quaternary ammonium disinfectants on the persistence of listeria monocytogenes in food processing environments.the persistence of certain strains of listeria monocytogenes, even after the food processing environment has been cleaned and disinfected, suggests that this may be related to phenomena that reduce the concentration of the disinfectants to subinhibitory levels. this includes (i) the existence of environmental niches or reservoirs that are difficult for disinfectants to reach, (ii) microorganisms that form biofilms and create microenvironments in which adequate concentrations of disinfectants can ...201627199964
temperature significantly affects the plaquing and adsorption efficiencies of listeria phages.listeria-infecting phages are currently being used to control and detect the important foodborne pathogen listeria monocytogenes; however, the influence of environmental conditions on the interactions between l. monocytogenes and its phages has not been explored in depth. here, we examined the infective potential of four listeria phages (two each from the p70-like and p100-like phages of listeria) against five strains of l. monocytogenes (representing serotypes 1/2a, 1/2b, 4a, and 4b) grown unde ...201627199957
application of electron-beam irradiation combined with aging for improvement of microbiological and physicochemical quality of beef loin.the combined effects of irradiation and aging temperature on the microbial and chemical quality of beef loin were investigated. the samples were vacuum-packaged, irradiated at 0 or 2 kgy using electron-beam (eb), and stored for 10 d at different aging temperatures (2, 14, or 25℃). the microbial growth, shear values, meat color, and nucleotide-related flavor compounds of the samples were analyzed. the irradiation effect on inactivation of foodborne pathogens was also investigated. the population ...201627194930
atf3 provides protection from staphylococcus aureus and listeria monocytogenes infections. 201627190243
identification of a lipoteichoic acid glycosyltransferase enzyme reveals that gw-domain-containing proteins can be retained in the cell wall of listeria monocytogenes in the absence of lipoteichoic acid or its modifications.listeria monocytogenes is a foodborne gram-positive bacterial pathogen, and many of its virulence factors are either secreted proteins or proteins covalently or noncovalently attached to the cell wall. previous work has indicated that noncovalently attached proteins with gw (glycine-tryptophan) domains are retained in the cell wall by binding to the cell wall polymer lipoteichoic acid (lta). lta is a glycerol phosphate polymer, which is modified in l. monocytogenes with galactose and d-alanine r ...201627185829
survival and metabolic activity of listeria monocytogenes on ready-to-eat roast beef stored at 4 °c.three brands of commercial roast beef were purchased and artificially inoculated with a 5-strain listeria monocytogenes cocktail at 2 inoculation levels (approximately 3 and 6 log cfu/g). although all 3 brands contained sodium diacetate and sodium lactate, inoculated listeria cocktail survived for 16 d in all 3 brands; significant increases in l. monocytogenes numbers were seen on inoculated brand b roast beef on days 12 and 16. numbers of l. monocytogenes increased to 4.14 log cfu/g for the 3 l ...201627258789
draft genome sequences of listeria monocytogenes serotype 4b strains 944 and 2993 and serotype 1/2c strains 198 and 2932.listeria monocytogenes is a foodborne pathogen and the causative agent of listeriosis among humans and animals. the draft genome sequences of l. monocytogenes serotype 4b strains 944 and 2993 and serotype 1/2c strains 198 and 2932 are reported here.201627257200
rab32/38 and the xenophagic restriction of intracellular bacteria replication.rab gtpases' subversion by intracellular pathogens during infection has been extensively documented. recent findings have implicated a key intracellular bacterial restriction/containment function for rab32/38 in salmonella species in macrophages and listeria monocytogenes in dendritic cells. rab32/38 aids the phagolysosome maturation, and mediates a parallel xenophagy mechanism by engaging prohibitins.201627256464
listeriosis: is it a rare disease in thailand?the prevalence of listeria monocytogenes infection has been characterized as rare in thailand. within one month, 3 cases of listeriosis were seen at vachira phuket hospital in phuket, thailand. two cases were neonates with septicemia, of which one made an uneventful recovery and the other expired. the third case was an eleven-year-old boy with meningitis who also succumbed to his illness. all isolated l. monocytogenes were sensitive to ampicillin. an outbreak investigation revealed no l. monocyt ...201627249907
recovery and growth potential of listeria monocytogenes in temperature abused milkshakes prepared from naturally contaminated ice cream linked to a listeriosis outbreak.the recovery and growth potential of listeria monocytogenes was evaluated in three flavors of milkshakes (vanilla, strawberry, and chocolate) that were prepared from naturally contaminated ice cream linked to a listeriosis outbreak in the u.s. in 2015, and were subsequently held at room temperature for 14 h. the average lag phase duration of l. monocytogenes was 9.05 h; the average generation time was 1.67 h; and the average population level increase per sample at 14 h was 1.14 log cfu/g. milksh ...201627242775
microbial safety and overall quality of cantaloupe fresh-cut pieces prepared from whole fruit after wet steam treatment.fresh-cut cantaloupes have been associated with outbreaks of salmonellosis. minimally processed fresh-cut fruits have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. the objectives of this study were to use a wet steam process to 1) reduce indigenous spoilage microflora and inoculated populations of salmonella, escherichia coli o157:h7 and listeria monocytogenes on the surface of cantaloupes, and 2) reduce the populations counts in cantalo ...201627240141
foodborne listeria monocytogenes: a real challenge in quality control.listeria monocytogenes is a foodborne pathogen, and the detection and differentiation of this bacterium from the nonpathogenic listeria species are of great importance to the food industry. differentiation of listeria species is very difficult, even with the sophisticated maldi-tof ms technique because of the close genetic relationship of the species and the usual gene transfer. the present paper emphasizes the difficulties of the differentiation through the standardized detection and confirmati ...201627239376
virulence factors and resistance to antimicrobials in listeria monocytogenes serotype 1/2c isolated from food.the aim of this study was to assess the potential risk posed to the human population by the presence of listeria monocytogenes serotype 1/2c in food based on the characterization of virulence factors of listeria involved in the invasion of host cells and sensitivity to antimicrobial agents.201627238881
use of whole genome sequencing and patient interviews to link a case of sporadic listeriosis to consumption of prepackaged lettuce.we report on a case of listeriosis in a patient who probably consumed a prepackaged romaine lettuce-containing product recalled for listeria monocytogenes contamination. although definitive epidemiological information demonstrating exposure to the specific recalled product was lacking, the patient reported consumption of a prepackaged romaine lettuce-containing product of either the recalled brand or a different brand. a multinational investigation found that patient and food isolates from the r ...201627296429
transfer of pathogens from cantaloupe rind to preparation surfaces and edible tissue as a function of cutting method.whole and cut cantaloupes have been implicated as vehicles in foodborne illness outbreaks of norovirus, salmonellosis, and listeriosis. preparation methods that minimize pathogen transfer from external surfaces to the edible tissue are needed. two preparation methods were compared for the transfer of listeria monocytogenes, salmonella enterica serovar typhimurium lt2, murine norovirus, and tulane virus from inoculated cantaloupe rinds to edible tissue and preparation surfaces. for the first meth ...201627296423
capacity of listeria monocytogenes strains from the 2011 cantaloupe outbreak to adhere, survive, and grow on cantaloupe.the 2011 listeriosis outbreak attributed to whole cantaloupe involved several genetically distinct strains of serotypes 1/2a and 1/2b that had not been previously reported in invasive listeriosis outbreaks. here we investigated the potential of strains from the 2011 cantaloupe outbreak to adhere, survive, and grow on cantaloupe rind and flesh and in juice extracted from cantaloupe at different temperatures (4, 8, and 25°c). all strains were able to adhere and grow, with ∼10-fold increases after ...201627296422
an outbreak of human listeriosis in england between 2010 and 2012 associated with the consumption of pork pies.an outbreak of listeriosis in england affecting 14 people between 2010 and 2012 and linked to the consumption of pork pies was investigated. all 14 individuals were older than 55 years, 12 were men, and 10 reported the presence of an underlying condition. all were resident in or had visited either of two english regions and were infected with the same strain of listeria monocytogenes. in interviews with 12 patients, 9 reported eating pork pies, and individuals that consumed pork pies were signif ...201627296419
fate of listeria monocytogenes in fresh apples and caramel apples.an outbreak of listeriosis in late 2014 and early 2015 associated with caramel apples led to questions about how this product became a vector for listeria monocytogenes. this investigation aimed to determine information about the survival and growth of l. monocytogenes in both fresh apples and caramel apples, specifically examining the effects of site and level of inoculation, inoculum drying conditions, and storage temperature. at a high inoculation level (7 log cfu per apple), l. monocytogenes ...201627296414
bacterial manipulation of nk cell regulatory activity increases susceptibility to listeria monocytogenes infection.natural killer (nk) cells produce interferon (ifn)-γ and thus have been suggested to promote type i immunity during bacterial infections. yet, listeria monocytogenes (lm) and some other pathogens encode proteins that cause increased nk cell activation. here, we show that stimulation of nk cell activation increases susceptibility during lm infection despite and independent from robust nk cell production of ifnγ. the increased susceptibility correlated with il-10 production by responding nk cells. ...201627295349
whole genome sequence-based serogrouping of listeria monocytogenes isolates.whole genome sequencing (wgs) is currently becoming the method of choice for characterization of listeria monocytogenes isolates in national reference laboratories (nrls). wgs is superior with regards to accuracy, resolution and analysis speed in comparison to several other methods including serotyping, pcr, pulsed field gel electrophoresis (pfge), multilocus sequence typing (mlst), multilocus variable number tandem repeat analysis (mlva), and multivirulence-locus sequence typing (mvlst), which ...201627288594
propagation method for persistent high yield of diverse listeria phages on permissive hosts at refrigeration temperatures.the efficient production of a high concentration of bacteriophage in large volumes has been a limiting factor in the exploration of the true potential of these organisms for biotechnology, agriculture and medicine. traditional methods focus on generating small volumes of highly concentrated samples as the end product of extensive mechanical and osmotic processing. to function at an industrial scale mandates extensive investment in infrastructure and input materials not feasible for many smaller ...201627287043
risk assessment of human listeriosis from semisoft cheeses made from raw sheep's milk in lazio and tuscany (italy).semisoft cheese made from raw sheep's milk is traditionally and economically important in southern europe. however, raw milk cheese is also a known vehicle of human listeriosis and contamination of sheep cheese with listeria monocytogenes has been reported. in the present study, we have developed and applied a quantitative risk assessment model, based on available evidence and challenge testing, to estimate risk of invasive listeriosis due to consumption of an artisanal sheep cheese made with ra ...201627285819
new antimicrobial peptides against foodborne pathogens: from in silico design to experimental evidence.recently there has been growing interest in the discovery of new antimicrobial agents to increase safety and shelf-life of food products. here, we developed an innovative approach by introducing the concept that mitochondrial targeting peptides (mtp) can interact and disrupt bacterial membranes, acting as antimicrobial agents. as proof-of-principle, we used a multidisciplinary strategy by combining in silico predictions, docking simulations and antimicrobial assays, to identify two peptides, mtp ...201627283665
sharing is caring: international sharing of data enhances genomic surveillance of listeria monocytogenes. 201627282712
the effect of oxygen on bile resistance in listeria monocytogenes.listeria monocytogenes is a gram-positive facultative anaerobe that is the causative agent of the disease listeriosis. the infectious ability of this bacterium is dependent upon resistance to stressors encountered within the gastrointestinal tract, including bile. previous studies have indicated bile salt hydrolase activity increases under anaerobic conditions, suggesting anaerobic conditions influence stress responses. therefore, the goal of this study was to determine if reduced oxygen availab ...201627274623
listeriosis downregulates hepatic cytochrome p450 enzymes in sublethal murine infection.listeria monocytogenes (lm) can cross the intestinal barrier in humans and then disseminates into different organs. invasion of the liver occurs even in sublethal infections, however, knowledge of affected physiological processes is scarce. this study employed a sublethal murine infection model to investigate liver responses systematically by proteomics.201627273978
listeria monocytogenes endophthalmitis - case report and review of risk factors and treatment outcomes.the majority of cases of endophthalmitis are caused by exogenous pathogens; only 5-10 % are of endogenous origin. one cause of these rare cases of endogenous endophthalmitis is listeria monocytogenes. twenty-six cases of endophthalmitis due to this pathogen have been published over the last twenty years. the aim of this review is to summarize the main risk factors and common clinical findings of endogenous endophthalmitis due to listeria monocytogenes.201627424034
three novel c1q domain containing proteins from the disk abalone haliotis discus discus: genomic organization and analysis of the transcriptional changes in response to bacterial pathogens.the globular c1q (gc1q) domain containing proteins, commonly referred as c1q domain containing (c1qdc) proteins, are an essential family of proteins involved in various innate immune responses. in this study, three novel c1qdc proteins were identified from the disk abalone (haliotis discus discus) transcriptome database and designated as abc1qdc1, abc1qdc2, and abc1qdc3. the cdna sequences of abc1qdc1, abc1qdc2, and abc1qdc3 consisted of 807, 1305, and 660 bp open reading frames (orfs) encoding ...201627417231
an in vivo selection identifies listeria monocytogenes genes required to sense the intracellular environment and activate virulence factor expression.listeria monocytogenes is an environmental saprophyte and facultative intracellular bacterial pathogen with a well-defined life-cycle that involves escape from a phagosome, rapid cytosolic growth, and acta-dependent cell-to-cell spread, all of which are dependent on the master transcriptional regulator prfa. the environmental cues that lead to temporal and spatial control of l. monocytogenes virulence gene expression are poorly understood. in this study, we took advantage of the robust up-regula ...201627414028
[pi3-kinase activation is critical for host barrier permissiveness to listeria monocytogenes]. 201627406757
tlr and tnf-r1 activation of the mkk3/mkk6-p38α axis in macrophages is mediated by tpl-2 kinase.previous studies suggested that toll-like receptor (tlr) stimulation of the p38α map kinase (mapk) is mediated by transforming growth factor-β-activated kinase 1 (tak1) activation of mapk kinases, mkk3, mkk4 and mkk6. we used quantitative mass spectrometry to monitor tumour progression locus 2 (tpl-2)-dependent protein phosphorylation following tlr4 stimulation with lipopolysaccharide, comparing macrophages from wild-type mice and map3k8(d270a/d270a) mice expressing catalytically inactive tpl-2 ...201627402796
il-17a-producing resident memory γδ t cells orchestrate the innate immune response to secondary oral listeria monocytogenes infection.memory γδ t cells are important for the clearance of listeria monocytogenes infection in the intestinal mucosa. however, the mechanisms by which memory γδ t cells provide protection against secondary oral infection are poorly understood. here we used a recombinant strain of l. monocytogenes that efficiently invades the intestinal epithelium to show that vγ4(+) memory γδ t cells represent a resident memory (trm) population in the mesenteric lymph nodes (mlns). the γδ trm exhibited a remarkably st ...201627402748
two novel members of the lhrc family of small rnas in listeria monocytogenes with overlapping regulatory functions but distinctive expression profiles.multicopy small rnas (srnas) have gained recognition as an important feature of bacterial gene regulation. in the human pathogen listeria monocytogenes, 5 homologous srnas, called lhrc1-5, control gene expression by base pairing to target mrnas though 3 conserved uccc motifs common to all 5 lhrcs. we show here that the srnas rli22 and rli33-1 are structurally and functionally related to lhrc1-5, expanding the lhrc family to 7 members, which makes it the largest multicopy srna family reported so ...201627400116
influence of food intrinsic complexity on listeria monocytogenes growth in/on vacuum-packed model systems at suboptimal temperatures.food intrinsic factors e.g., food (micro)structure, compositional and physicochemical aspects, which are mutually dependent, influence microbial growth. while the effect of composition and physicochemical properties on microbial growth has been thoroughly assessed and characterised, the role of food (micro)structure still remains unravelled. most studies on food (micro)structure focus on comparing planktonic growth in liquid (microbiological) media with colonial growth in/on solid-like systems o ...201627393885
cyclic di-amp targets the cystathionine beta-synthase domain of the osmolyte transporter opuc.cellular turgor is of fundamental importance to bacterial growth and survival. changes in external osmolarity as a consequence of fluctuating environmental conditions and colonization of diverse environments can significantly impact cytoplasmic water content, resulting in cellular lysis or plasmolysis. to ensure maintenance of appropriate cellular turgor, bacteria import ions and small organic osmolytes, deemed compatible solutes, to equilibrate cytoplasmic osmolarity with the extracellular envi ...201627378384
a human pathogenic bacterial infection model using the two-spotted cricket, gryllus bimaculatus.invertebrate animal species that can withstand temperatures as high as 37°c, the human body temperature, are limited. in the present study, we utilized the two-spotted cricket, gryllus bimaculatus, which lives in tropical and subtropical regions, as an animal model of human pathogenic bacterial infection. injection of pseudomonas aeruginosa or staphylococcus aureus into the hemolymph killed crickets. injected p. aeruginosa or s. aureus proliferated in the hemolymph until the cricket died. the ab ...201627377894
survival and growth of listeria monocytogenes on whole cantaloupes is dependent on site of contamination and storage temperature.whole cantaloupes (cucumis melo l.), marketed as 'rocky ford', were implicated in a large multi-state outbreak of listeriosis in the united states in 2011; however, survival and growth of listeria monocytogenes on whole cantaloupes remains relatively unexplored. the research presented here evaluated three different storage temperatures, two sites of contamination of cantaloupes, and two cantaloupe varieties to determine their effect on the survival of l. monocytogenes. 'athena' and 'rocky ford' ...201627376678
antilisterial peptides from spanish dry-cured hams: purification and identification.the typical spanish dry-cured ham has a particular sensory quality that makes it a distinctive food, highly appreciated for consumers worldwide. its particular physicochemical properties, such as high salt content and reduced water activity contribute to their shelf-stability. however, post-processing actions carried out for the commercialization of these products such as slicing may increase the risk of development of pathogenic microorganisms as listeria monocytogenes. during ripening, muscle ...201627375254
chitosan boosts the antimicrobial activity of origanum vulgare essential oil in modified atmosphere packaged pork.the potential of chitosan as a possible booster of the antimicrobial activity of origanum vulgare eo (oeo) against spoilage bacteria and listeria monocytogenes was investigated in fresh pork meat. pork fillets were inoculated with 3 l. monocytogenes strains, dipped either in origanum vulgare (oregano) essential oil (oeo) at 2 and 4%, or in chitosan 1% alone or added with 2 and 4% oeo, then packed under modified atmosphere (70% o2, 20% co2, 10% n2) and stored at 4 °c for 15 days. oeo did not redu ...201627375241
potential for transfer of escherichia coli o157:h7, listeria monocytogenes and salmonella senftenberg from contaminated food waste derived compost and anaerobic digestate liquid to lettuce plants.the diversion of food wastes from landfill to sustainable disposal methods, such as composting and anaerobic digestion, has led to an increase in the soil amendment products that are now commercially available and which are derived from both of these processes. the use of such products as soil amendments during the production of ready-to-eat (rte) crops is increasing worldwide. the aim of this study was to investigate the potential of three well-recognised bacterial pathogens of importance to pu ...201627375239
listeria monocytogenes meningitis in the elderly: epidemiological, clinical and therapeutic findings.listeria monocytogenes is a gram-positive bacillus and facultative intracellular bacterium whose transmission occurs mainly through the consumption of contaminated food, l. monocytogenes invades the host cells using various protein and can escape to the human t-cell immune system by cell-to-cell spreading. if the infection is not controlled at the stage in which the bacterium is in the liver, for instance, due to a severe immunodepression, a secondary bacteraemia can be developed and l. monocyto ...201627367319
microbial indicator profiling of fresh produce and environmental samples from farms and packing facilities in northern mexico.to compare microbiological indicator and pathogen contamination among different types of fresh produce and environmental samples along the production chain, 636 samples of produce (rinsates from cantaloupe melons, jalapeño peppers, and tomatoes) and environmental samples (rinsates from hands of workers, soil, and water) were collected at four successive steps in the production process (from the field before harvest through the packing facility) on 11 farms in northern mexico during 2011 and 2012 ...201627357040
effect of grapefruit seed extract on thermal inactivation of listeria monocytogenes during sous-vide processing of two marinated mexican meat entrées.d- and z-values for listeria monocytogenes were obtained for two mexican meat entrées: pork meat marinated in tomatillo (green tomato) sauce (pts) and beef marinated in a red chili sauce (brcs), with addition of 0, 200, and 800 ppm of grapefruit seed extract (gse). meat samples inoculated with l. monocytogenes were packaged in sterile bags, immersed in a water bath, and held at 55, 57.5, 60, and 62.5°c for different periods of time. depending upon the temperature, d-values at 0 ppm of gse ranged ...201627357037
listeria monocytogenes in retail delicatessens: an interagency risk assessment-risk mitigations.cross-contamination, improper holding temperatures, and insufficient sanitary practices are known retail practices that may lead to product contamination and growth of listeria monocytogenes. however, the relative importance of control options to mitigate the risk of invasive listeriosis from ready-to-eat (rte) products sliced or prepared at retail is not well understood. this study illustrates the utility of a quantitative risk assessment model described in a first article of this series (pouil ...201627357026
expansion of amphibian intronless interferons revises the paradigm for interferon evolution and functional diversity.interferons (ifns) are key cytokines identified in vertebrates and evolutionary dominance of intronless ifn genes in amniotes is a signature event in ifn evolution. for the first time, we show that the emergence and expansion of intronless ifn genes is evident in amphibians, shown by 24-37 intronless ifn genes in each frog species. amphibian ifns represent a molecular complex more complicated than those in other vertebrate species, which revises the established model of ifn evolution to facilita ...201627356970
effect of glucose on listeria monocytogenes biofilm formation, and assessment of the biofilm's sanitation tolerance.listeria monocytogenes is an important cause of human foodborne infections and its ability to form biofilms is a serious concern to the food industry. to reveal the effect of glucose conditions on biofilm formation of l. monocytogenes, 20 strains were investigated under three glucose conditions (0.1, 1.0, and 2.0% w v(-1)) by quantifying the number of cells in the biofilm and observing the biofilm structure after incubation for 24, 72, and 168 h. in addition, the biofilms were examined for their ...201627353113
dual-track clearance of circulating bacteria balances rapid restoration of blood sterility with induction of adaptive immunity.efficient clearance of bacteremia prevents life-threatening disease. platelet binding to intravascular bacteria, a process involving platelet glycoprotein gpib and bacterial opsonization with activated complement c3, influences blood clearance and anti-infective immunity. using intravital microscopy of the bloodstream of mice infected with listeria monocytogenes, we show that bacterial clearance is not a uniform process but a "dual-track" mechanism consisting of parallel "fast" and "slow" pathwa ...201627345696
[rhomboencephalitis and endocarditis caused by listeria monocytogenes: an unreported association]. 201627345281
photo-enhancement of macrophage phagocytic activity via rac1-mediated signaling pathway: implications for bacterial infection.phagocytosis and the subsequent destruction of invading pathogens by macrophages are indispensable steps in host immune responses to microbial infections. low-power laser irradiation (lpli) has been found to exert photobiological effects on immune responses, but the signaling mechanisms underlying this photobiomodulation of phagocytosis remains largely unknown. here, we demonstrated for the first time that lpli enhanced the phagocytic activity of macrophages by stimulating the activation of rac1 ...201627345261
listeria monocytogenes peritonitis in an hivinfected patient.we report the first case of listeria monocytogenes peritoneal dialysis (pd) peritonitis in a human immunodeficiency virus-infected individual successfully treated with intraperitoneal ampicillin, without the need for catheter removal. suspicion of listerial infection in at-risk individuals is critical as empiric antimicrobial treatment for pd-associated infections may be ineffective against this organism.201627345188
antibiotic treatment and mortality in patients with listeria monocytogenes meningitis or bacteraemia.invasive listeria monocytogenes infections carry a high mortality despite antibiotic treatment. the rareness of the infection makes it difficult to improve antibiotic treatment through randomized clinical trials. this observational study investigated clinical features and outcome of invasive l. monocytogenes infections including the efficacy of empiric and definitive antibiotic therapies. demographic, clinical and biochemical findings, antibiotic treatment and 30-day mortality for all episodes o ...201627345176
modeling and validation of the ecological behavior of wild-type listeria monocytogenes and stress-resistant variants.listeria monocytogenes exhibits a heterogeneous response upon stress exposure which can be partially attributed to the presence of stable stress-resistant variants. this study aimed to evaluate the impact of the presence of stress-resistant variants of listeria monocytogenes and their corresponding trade-offs on population composition under different environmental conditions. a set of stress robustness and growth parameters of the wild type (wt) and an rpsu deletion variant was obtained and used ...201627342563
identification of surface protein biomarkers of listeria monocytogenes via bioinformatics and antibody-based protein detection tools.the gram-positive bacterium listeria monocytogenes causes a significant percentage of the fatalities among foodborne illnesses in humans. surface proteins specifically expressed in a wide range of l. monocytogenes serotypes under selective enrichment culture conditions could serve as potential biomarkers for detection and isolation of this pathogen via antibody-based methods. our study aimed to identify such biomarkers. interrogation of the l. monocytogenes serotype 4b strain f2365 genome identi ...201627342549
factors influencing the time between onset of illness and specimen collection in the diagnosis of non-pregnancy associated listeriosis in england and wales.listeriosis is an opportunistic bacterial infection caused by listeria monocytogenes and predominantly affects people who are immunocompromised. due to its severity and the population at risk, prompt clinical diagnosis and treatment of listeriosis is essential. a major step to making a clinical diagnosis is the collection of the appropriate specimen(s) for testing. this study explores factors that may influence the time between onset of illness and collection of specimen in order to inform clini ...201627341796
rna purification from intracellularly grown listeria monocytogenes in macrophage cells.analysis of the transcriptome of bacterial pathogens during mammalian infection is a valuable tool for studying genes and factors that mediate infection. however, isolating bacterial rna from infected cells or tissues is a challenging task, since mammalian rna mostly dominates the lysates of infected cells. here we describe an optimized method for rna isolation of listeria monocytogenes bacteria growing within bone marrow derived macrophage cells. upon infection, cells are mildly lysed and rapid ...201627341521
is the lysm domain of l. monocytogenes p60 protein suitable for engineering a protein with high peptidoglycan binding affinity?lysin motif (lysm) is a highly conserved carbohydrate binding module that is widely present in proteins from both prokaryotes and eukaryotes. lysm domains from many lysm-containing proteins can be taken out of their natural context and retain their ability to bind peptidoglycan. therefore, lysm has enormous potential for applications in both industry and medicine. this potential has stimulated an intensive search for lysm modules with different evolutionary origins. the p60 protein (lm-p60) is a ...201627333274
physical and antimicrobial properties of cinnamon bark oil co-nanoemulsified by lauric arginate and tween 80.lauric arginate (lae) is a water-soluble cationic surfactant which has antimicrobial activity against a broad spectrum of foodborne pathogens. some spice essential oils are effective lipophilic antimicrobials. combining both antimicrobials may reduce their usage levels and possible negative sensory impacts when applied in complex food matrices. the objective of this study was to combine a nonionic surfactant (tween 80) with lae to form stable nanoemulsions with cinnamon bark essential oil (cbo) ...201627322724
broad substrate specificity of phosphotransbutyrylase from listeria monocytogenes: a potential participant in an alternative pathway for provision of acyl coa precursors for fatty acid biosynthesis.listeria monocytogenes, the causative organism of the serious food-borne disease listeriosis, has a membrane abundant in branched-chain fatty acids (bcfas). bcfas are normally biosynthesized from branched-chain amino acids via the activity of branched chain α-keto acid dehydrogenase (bkd), and disruption of this pathway results in reduced bcfa content in the membrane. short branched-chain carboxylic acids (bccas) added as media supplements result in incorporation of bcfas arising from the supple ...201627320015
rapid and visual detection of listeria monocytogenes based on nanoparticle cluster catalyzed signal amplification.foodborne pathogens pose a significant threat to human health worldwide. the identification of foodborne pathogens needs to be rapid, accurate and convenient. here, we constructed a nanoparticle cluster (npc) catalyzed signal amplification biosensor for foodborne pathogens visual detection. in this work, vancomycin (van), a glycopeptide antibiotic for gram-positive bacteria, was used as the first molecular recognition agent to capture listeria monocytogenes (l. monocytogenes). fe3o4 npc modified ...201627318103
adiponectin enhances antibacterial activity of hematopoietic cells by suppressing bone marrow inflammation.obesity has been shown to increase the morbidity of infections, however, the underlying mechanisms remain largely unknown. here we demonstrate that obesity caused adiponectin deficiency in the bone marrow (bm), which led to an inflamed bm characterized by increased tumor necrosis factor (tnf) production from bone marrow macrophages. hematopoietic stem and progenitor cells (hspcs) chronically exposed to excessive tnf in obese marrow aberrantly expressed cytokine signaling suppressor socs3, impair ...201627317261
a case of leukocytoclastic vasculitis caused by listeria monocytogenes bacteremia.importance. infections can cause leukocytoclastic vasculitis. observations. we report the case of a patient with a left ventricular assist device who presented with acute kidney injury and biopsy proven leukocytoclastic vasculitis. blood cultures grew listeria monocytogenes. the patient's rash improved with treatment of the underlying listeria infection. conclusion. clinicians should be aware that there are a number of broad categories of disease associated with the histologic finding of vasculi ...201627313916
the small colony variant of listeria monocytogenes is more tolerant to antibiotics and has altered survival in raw 264.7 murine macrophages.small colony variant (scv) cells of bacteria are a slow-growing phenotype that result from specific defects in the electron transport chain. they form pinpoint colonies on agar plates and have a variety of phenotypic characteristics, such as altered carbon metabolism, decreased toxin and lytic enzyme production, aminoglycoside resistance, and increased intracellular persistence. they are clinically relevant in staphylococcus aureus and pseudomonas aeruginosa, serving as a reservoir for recurrent ...201627458449
purification and characterization of a rabbit serum factor that kills listeria species and other foodborne bacterial pathogens.in an in-vitro assay, rabbit serum, but not human serum, killed listeria monocytogenes, a foodborne pathogen. the aim of our study was to purify and partially characterize this killing factor. listericidin was purified from rabbit serum by a single-step ion-exchange chromatography with deae-sephadex a-50 and its antimicrobial activity was assessed by a microdilution method. listericidin is a protein with a molecular weight of 9 kda and an isoelectric point of 8.1. it kills l. monocytogenes at 4° ...201627455064
artemisia arborescens essential oil composition, enantiomeric distribution, and antimicrobial activity from different wild populations from the mediterranean area.aerial parts of artemisia arborescens were collected from different sites of the mediterranean area (southwestern algeria and southern italy) and the chemical composition of their essential oil (eo) extracted by hydrodistillation was studied by both gas chromatography (gc) equipped with an enantioselective capillary column and gc/mass spectrometry (gc/ms). the eos obtained were tested against several listeria monocytogenes strains. using gc and gc/ms, 41 compounds were identified, accounting for ...201627447740
inactivation of salmonella enterica and listeria monocytogenes in cantaloupe puree by high hydrostatic pressure with/without added ascorbic acid.the objective of this research was to evaluate and develop a method for inactivation of salmonella enterica and listeria monocytogenes in cantaloupe puree (cp) by high hydrostatic pressure (hhp). cantaloupe being the most netted varieties of melons presents a greater risk of pathogen transmission. freshly prepared cp with or without 0.1% ascorbic acid (aa) was inoculated with a bacterial cocktail composed of a three serotype mixture of s. enterica (s. poona, s. newport h1275 and s. stanley h0558 ...201627441819
capture and concentration of viral and bacterial foodborne pathogens using apolipoprotein h.the need for improved pathogen separation and concentration methods to reduce time-to-detection for foodborne pathogens is well recognized. apolipoprotein h (apoh) is an acute phase human plasma protein that has been previously shown to interact with viruses, lipopolysaccharides (lps) and bacterial proteins. the purpose of this study was to determine if apoh was capable of binding and efficiently capturing two representative human norovirus strains (gi.1 and gii.4), a cultivable surrogate, and f ...201627439140
listeria monocytogenes cross-contamination of cheese: risk throughout the food supply chain.listeria monocytogenes has been the most common microbial cause of cheese-related recalls in both the united states and canada in recent years. since l. monocytogenes is inactivated by pasteurization, the majority of these cases have been linked to environmental and cross-contamination of fresh-soft, soft-ripened, and semi-soft cheeses. cross-contamination of foods with l. monocytogenes is a continuous risk throughout the food supply chain and presents unique challenges for subsequent illness an ...201627435307
growth differences and competition between listeria monocytogenes strains determine their predominance on ham slices and lead to bias during selective enrichment with the iso protocol.listeria monocytogenes strains are widespread in the environment where they live well mixed, often resulting in multiple strains contaminating a single food sample. the occurrence of different strains in the same food might trigger strain competition, contributing to uneven growth of strains in food and to bias during selective procedures. we tested the growth of seven l. monocytogenes strains (c5, 6179, scotta, pl24, pl25, pl26, pl27) on ham slices and on nutrient-rich agar at 10°c, singly and ...201627434679
application of lemongrass oil-containing polylactic acid films to the packaging of pork sausages.polylactic acid (pla) is a biodegradable and renewable polymer, which represents a valuable alternative to plastic packaging films, often associated with environmental problems. in this study, we tested the suitability of pla as a biodegradable packaging film and assessed the antimicrobial activity of lemongrass oil (lo), incorporated into the pla film in different concentrations. to obtain the optimal physical properties for pla films, tensile strength, elongation at break, and water vapor perm ...201627433114
biofilm formation and disinfectant susceptibility of persistent and nonpersistent listeria monocytogenes isolates from gorgonzola cheese processing plants.the aim of this study was to investigate whether the biofilm-forming ability and/or the disinfectant susceptibility accounted for the persistence of listeria monocytogenes in gorgonzola cheese processing plants. for this purpose, a set of 16 l. monocytogenes isolates collected in the 2004-2007 period was analyzed, including 11 persistent isolates collected in different years, within the collection period, and displaying identical or highly correlated pulsotypes. the evaluation of biofilm-forming ...201627462729
influence of environmental factors on phage-bacteria interaction and on the efficacy and infectivity of phage p100.when using bacteriophages to control food-borne bacteria in food production plants and processed food, it is crucial to consider that environmental conditions influence their stability. these conditions can also affect the physiological state of bacteria and consequently host-virus interaction and the effectiveness of the phage ability to reduce bacteria numbers. in this study we investigated the stability, binding, and replication capability of phage p100 and its efficacy to control listeria mo ...201627516757
review of prosthetic joint infection from listeria monocytogenes.prosthetic joint infection from listeria monocytogenes is rare. we decided to shed light on this illness and review the reported cases to better understand its characteristics.201627513716
cryptococcus gattii meningitis complicated by listeria monocytogenes infection. 201627532498
achillea schurii flowers: chemical, antioxidant, and antimicrobial investigations.this study aims to evaluate the phenolic profile, and antioxidant and antimicrobial activity of achillea schurii sch.-bip., an endemic species from romania that has not been investigated yet. the chromatographic profile of the phenolic components was obtained using the hplc-ms method, while the total polyphenol, flavonoid, caffeic acid derivative contents were quantified using spectrophotometric methods. the antioxidant activity was evaluated using different methods: dpph radical scavenging, hem ...201627529204
antifungal and antibacterial activities of petroselinum crispum essential oil.parsley [petroselinum crispum (mill.) fuss] is regarded as an aromatic, culinary, and medicinal plant and is used in the cosmetic, food, and pharmaceutical industries. however, few studies with conflicting results have been conducted on the antimicrobial activity of parsley essential oil. in addition, there have been no reports of essential oil obtained from parsley aerial parts, except seeds, as an alternative natural antimicrobial agent. also, microorganism resistance is still a challenge for ...201627525894
adhesion- and degranulation-promoting adapter protein promotes cd8 t cell differentiation and resident memory formation and function during an acute infection.during acute infections, naive ag-specific cd8 t cells are activated and differentiate into effector t cells, most of which undergo contraction after pathogen clearance. a small population of cd8 t cells persists as memory to protect against future infections. we investigated the role of adhesion- and degranulation-promoting adapter protein (adap) in promoting cd8 t cell responses to a systemic infection. naive ag-specific cd8 t cells lacking adap exhibited a modest expansion defect early after ...201627521337
core genome multilocus sequence typing for identification of globally distributed clonal groups and differentiation of outbreak strains of listeria monocytogenes.many listeriosis outbreaks are caused by a few globally distributed clonal groups, designated clonal complexes or epidemic clones, of listeria monocytogenes, several of which have been defined by classic multilocus sequence typing (mlst) schemes targeting 6 to 8 housekeeping or virulence genes. we have developed and evaluated core genome mlst (cgmlst) schemes and applied them to isolates from multiple clonal groups, including those associated with 39 listeriosis outbreaks. the cgmlst clusters we ...201627520821
engineering a prototypic p-type atpase listeria monocytogenes ca(2+)-atpase 1 for single-molecule fret studies.approximately 30% of the atp generated in the living cell is utilized by p-type atpase primary active transporters to generate and maintain electrochemical gradients across biological membranes. p-type atpases undergo large conformational changes during their functional cycle to couple atp hydrolysis in the cytoplasmic domains to ion transport across the membrane. the ca(2+)-atpase from listeria monocytogenes, lmca1, was found to be a suitable model of p-type atpases and was engineered to facili ...201627501274
human placental and decidual organ cultures to study infections at the maternal-fetal interface.the placenta shows a large degree of interspecies anatomic variability. to best understand biology and pathophysiology of the human placenta, it is imperative to design experiments using human cells and tissues. an advantage of organ culture is maintenance of three-dimensional (3d) structural organization and extracellular matrix. the goal of the method described here is successful establishment of ex vivo human gestational tissue organ cultures and their healthy culture maintenance for 72-96 hr ...201627500727
evolution and diversity of listeria monocytogenes from clinical and food samples in shanghai, china.listeria monocytogenes is a significant foodborne pathogen causing severe systemic infections in humans with high mortality rates. the objectives of this work were to establish a phylogenetic framework of l. monocytogenes from china and to investigate sequence diversity among different serotypes. we selected 17 l. monocytogenes strains recovered from patients and foods in china representing serotypes 1/2a, 1/2b, and 1/2c. draft genome sequences were determined using illumina miseq technique and ...201627499751
internalization of listeria monocytogenes in whole avocado.in recent years, tree fruits have emerged as a new concern for listeria monocytogenes contamination. the objective of the current study was to evaluate the potential internalization of l. monocytogenes from the surface of avocados into the edible portions of the fruit during certain postharvest practices simulated in a laboratory setting. one set of intact avocados was spot inoculated with l. monocytogenes on the stem scar, and the second set was hydrocooled in water contaminated with l. monocyt ...201627497134
inhibition of listeria monocytogenes by buffered dry vinegar in reduced-sodium ready-to-eat uncured turkey stored at 4°c.a reduced-sodium ready-to-eat (rte) uncured turkey was manufactured with buffered dry vinegar treatments to validate the inhibition of listeria monocytogenes and spoilage microflora and to determine the effects on sensory and quality attributes. samples were stored at 4°c for 12 weeks, and the study was independently replicated three times. two different five-strain inocula of l. monocytogenes obtained from different sources were used for evaluating the efficacy of the buffered dry vinegar treat ...201627497127
effect of hydrogen peroxide in combination with minimal thermal treatment for reducing bacterial populations on cantaloupe rind surfaces and transfer to fresh-cut pieces.surface structure and biochemical characteristics of bacteria and produce play a major role in how and where bacteria attach, complicating decontamination treatments. whole cantaloupe rind surfaces were inoculated with salmonella, escherichia coli o157:h7, and listeria monocytogenes at 10(7) cfu/ml. average population size of salmonella, escherichia coli o157:h7, and l. monocytogenes recovered after surface inoculation was 4.8 ± 0.12, 5.1 ± 0.14, and 3.6 ± 0.13 log cfu/cm(2), respectively. inocu ...201627497118
quantitative image analysis to characterize the dynamics of listeria monocytogenes biofilms.this work shows that the combination of two-dimensional (2d) and three-dimensional (3d) analyses of images acquired by confocal laser scanning microscopy facilitates the quantitative spatiotemporal characterization of architectures formed by listeria monocytogenes biofilms. in particular, the analysis of structural features such as maximum thickness, biovolume, areal porosity and maximum diffusion distance allowed elucidating differences in biofilm formation of three l. monocytogenes strains (l1 ...201627494720
isolation and characterization of atypical listeria monocytogenes associated with a canine urinary tract infection.listeria monocytogenes, a well-described cause of encephalitis and abortion in ruminants and of food-borne illness in humans, is rarely associated with disease in companion animals. a case of urinary tract infection associated with an atypical, weakly hemolytic l. monocytogenes strain is described in a diabetic dog. the serotype of the l. monocytogenes isolate was determined to be 1/2a (3a), with the multilocus genotyping pattern 2.72_1/2a. a nucleotide substitution (gly145asp) was detected at r ...201627493137
genome sequence of listeria monocytogenes strain hpb2088 (serotype 1/2a), an environmental isolate collected in canada in 1994.listeria monocytogenes is a foodborne pathogen that causes severe illness. thus, ongoing efforts at real-time whole-genome sequencing are of utmost importance. however, it is also important that retrospective analyses that place these data into context be performed. here, we present the genome sequence of strain hpb2088, which was collected in 1994.201627491990
listeria monocytogenes inhibits serotonin transporter in human intestinal caco-2 cells.listeria monocytogenes is a gram-positive bacterium that can cause a serious infection. intestinal microorganisms have been demonstrated to contribute to intestinal physiology not only through immunological responses but also by modulating the intestinal serotonergic system. serotonin (5-ht) is a neuromodulator that is synthesized in the intestinal epithelium and regulates the whole intestinal physiology. the serotonin transporter (sert), located in enterocytes, controls intestinal 5-ht availabi ...201627488594
modeling the effect of temperature on survival rate of listeria monocytogenes in yogurt.the aim of the study was to (i) evaluate the behavior of listeria monocytogenes in a commercially produced yogurt, (ii) determine the survival/inactivation rates of l. monocytogenes during cold storage of yogurt and (iii) to generate primary and secondary mathematical models to predict the behavior of these bacteria during storage at different temperatures. the samples of yogurt were inoculated with the mixture of three l. monocytogenes strains and stored at 3, 6, 9, 12 and 15°c for 16 days. the ...201627487505
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