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a riboswitch-regulated antisense rna in listeria monocytogenes.riboswitches are ligand-binding elements located in 5' untranslated regions of messenger rnas, which regulate expression of downstream genes. in listeria monocytogenes, a vitamin b12-binding (b12) riboswitch was identified, not upstream of a gene but downstream, and antisense to the adjacent gene, pocr, suggesting it might regulate pocr in a nonclassical manner. in salmonella enterica, pocr is a transcription factor that is activated by 1,2-propanediol, and subsequently activates expression of t ...201323878253
iron induces bimodal population development by escherichia coli.bacterial biofilm formation is a complex developmental process involving cellular differentiation and the formation of intricate 3d structures. here we demonstrate that exposure to ferric chloride triggers rugose biofilm formation by the uropathogenic escherichia coli strain uti89 and by enteric bacteria citrobacter koseri and salmonella enterica serovar typhimurium. two unique and separable cellular populations emerge in iron-triggered, rugose biofilms. bacteria at the air-biofilm interface exp ...201323359678
new delhi metallo-β-lactamase-producing enterobacteriaceae, united states.we characterized 9 new delhi metallo-β-lactamase-producing enterobacteriaceae (5 klebsiella pneumoniae, 2 escherichia coli, 1 enterobacter cloacae, 1 salmonella enterica serovar senftenberg) isolates identified in the united states and cultured from 8 patients in 5 states during april 2009-march 2011. isolates were resistant to β-lactams, fluoroquinolones, and aminoglycosides, demonstrated mics ≤1 µg/ml of colistin and polymyxin, and yielded positive metallo-β-lactamase screening results. eight ...201323731823
genes ycfr, sira and yigg contribute to the surface attachment of salmonella enterica typhimurium and saintpaul to fresh produce.salmonella enterica is a frequent contaminant of minimally-processed fresh produce linked to major foodborne disease outbreaks. the molecular mechanisms underlying the association of this enteric pathogen with fresh produce remain largely unexplored. in our recent study, we showed that the expression of a putative stress regulatory gene, ycfr, was significantly induced in s. enterica upon exposure to chlorine treatment, a common industrial practice for washing and decontaminating fresh produce d ...201323451197
antimicrobial activity of amazonian medicinal plants.the aqueous extracts of currently utilized amazonian medicinal plants were assayed in vitro searching for antimicrobial activity against human and animal pathogenic microorganisms.201323961431
discrimination of enterobacteriaceae and non-fermenting gram negative bacilli by maldi-tof mass spectrometry.discrimination of enterobacteriaceae and non-fermenting gram negative bacilli by maldi-tof mass spectrometry matrix assisted laser desorption/ionization time of flight mass spectrometry (maldi-tof ms) has proven to be an effective identification tool in medical microbiology. discrimination to subspecies or serovar level has been found to be challenging using commercially available identification software. by forming our own reference database and using alternative analysis methods, we could reli ...201323919091
a chemical biology approach to interrogate quorum-sensing regulated behaviors at the molecular and cellular level.small molecule probes have been used extensively to explore biologic systems and elucidate cellular signaling pathways. in this study, we use an inhibitor of bacterial communication to monitor changes in the proteome of salmonella enterica serovar typhimurium with the aim of discovering unrecognized processes regulated by ai-2-based quorum-sensing (qs), a mechanism of bacterial intercellular communication that allows for the coordination of gene expression in a cell density-dependent manner. in ...201323890008
the calcium-stimulated lipid a 3-o deacylase from rhizobium etli is not essential for plant nodulation.the lipid a component of lipopolysaccharide from the nitrogen-fixing plant endosymbiont, rhizobium etli, is structurally very different from that found in most enteric bacteria. the lipid a from free-living r. etli is structurally heterogeneous and exists as a mixture of species which are either pentaacylated or tetraacylated. in contrast, the lipid a from r. etli bacteroids is reported to consist exclusively of tetraacylated lipid a species. the tetraacylated lipid a species in both cases lack ...201323583844
generation and selection of anti-flagellin monoclonal antibodies useful for serotyping salmonella enterica.in developing countries, bacterial acute gastroenteritis continues to be an important cause of morbidity and mortality among young children. salmonellosis constitutes a major cause of infectious enteritis worldwide, most of them associated to the consumption of contaminated food products. traditionally, salmonella has been classified in serovars based on varieties of o and h surface antigens. in the present work we generated and characterized a panel of anti-flagellin monoclonal antibodies (mabs ...201324349948
structural and functional characterization of scsc, a periplasmic thioredoxin-like protein from salmonella enterica serovar typhimurium.the prototypical protein disulfide bond (dsb) formation and protein refolding pathways in the bacterial periplasm involving dsb proteins have been most comprehensively defined in escherichia coli. however, genomic analysis has revealed several distinct dsb-like systems in bacteria, including the pathogen salmonella enterica serovar typhimurium. this includes the scsabcd locus, which encodes a system that has been shown via genetic analysis to confer copper tolerance, but whose biochemical proper ...201323642141
elucidation of the 3-o-deacylase gene, pagl, required for the removal of primary β-hydroxy fatty acid from the lipid a in the nitrogen-fixing endosymbiont rhizobium etli ce3.until now, the gene responsible for the 3-o-deacylation of lipid a among nitrogen-fixing endosymbionts has not been characterized. several gram-negative animal pathogens such as salmonella enterica, pseudomonas aeruginosa, and bordetella bronchiseptica contain an outer membrane 3-o-deacylase (pagl) that has been implicated in host immune evasion. the role of 3-o-deacylated lipid a among nitrogen-fixing endosymbionts, plant endophytes, and plant pathogens has not been studied. however, d'haeze et ...201323511636
a novel anti-microbial function for a familiar rab gtpase.salmonella enterica is a bacterial pathogen that closely interacts with its host and replicates intracellularly. it has evolved the ability to create an intracellular membrane vacuole where it can survive and replicate. the nature of the salmonella vacuole is still poorly understood, and although it has some features in common with lysosomes, it serves as a suitable niche for its survival. in contrast to broad-host salmonella enterica serovars, salmonella enterica serovar typhi (s. typhi) is a h ...201324321888
a novel antisense rna from the salmonella virulence plasmid pslt expressed by non-growing bacteria inside eukaryotic cells.bacterial small rnas (srnas) are regulatory molecules playing relevant roles in response to environmental changes, stressful conditions and pathogenesis. the intracellular bacterial pathogen salmonella enterica serovar typhimurium (s. typhimurium) is known to regulate expression of some srnas during colonization of fibroblasts. here, we characterize a previously unknown srna encoded in the s. typhimurium pslt virulence plasmid that is specifically up-regulated by non-growing dormant bacteria per ...201324205037
atg16l1 is required for autophagy in intestinal epithelial cells and protection of mice from salmonella infection.intestinal epithelial cells aid in mucosal defense by providing a physical barrier against entry of pathogenic bacteria and secreting antimicrobial peptides (amps). autophagy is an important component of immune homeostasis. however, little is known about its role in specific cell types during bacterial infection in vivo. we investigated the role of autophagy in the response of intestinal epithelial and antigen-presenting cells to salmonella infection in mice.201323973919
a bacterial virulence protein promotes pathogenicity by inhibiting the bacterium's own f1fo atp synthase.several intracellular pathogens, including salmonella enterica and mycobacterium tuberculosis, require the virulence protein mgtc to survive within macrophages and to cause a lethal infection in mice. we now report that, unlike secreted virulence factors that target the host vacuolar atpase to withstand phagosomal acidity, the mgtc protein acts on salmonella's own f1fo atp synthase. this complex couples proton translocation to atp synthesis/hydrolysis and is required for virulence. we establish ...201323827679
quantification of the effects of antibodies on the extra- and intracellular dynamics of salmonella enterica.antibodies are known to be essential in controlling salmonella infection, but their exact role remains elusive. we recently developed an in vitro model to investigate the relative efficiency of four different human immunoglobulin g (igg) subclasses in modulating the interaction of the bacteria with human phagocytes. our results indicated that different igg subclasses affect the efficacy of salmonella uptake by human phagocytes. in this study, we aim to quantify the effects of igg on intracellula ...201323235264
salmonella enterica suppresses pectobacterium carotovorum subsp. carotovorum population and soft rot progression by acidifying the microaerophilic environment.although enteric human pathogens are usually studied in the context of their animal hosts, a significant portion of their life cycle occurs on plants. plant disease alters the phyllosphere, leading to enhanced growth of human pathogens; however, the impact of human pathogens on phytopathogen biology and plant health is largely unknown. to characterize the interaction between human pathogens and phytobacterial pathogens in the phyllosphere, we examined the interactions between pectobacterium caro ...201323404399
cytosporone b, an inhibitor of the type iii secretion system of salmonella enterica serovar typhimurium.bacterial virulence factors have been increasingly regarded as attractive targets for development of novel antibacterial agents. virulence inhibitors are less likely to generate bacterial resistance, which makes them superior to traditional antibiotics that target bacterial viability. salmonella enterica serovar typhimurium, an important food-borne human pathogen, has type iii secretion system (t3ss) as its major virulence factor. t3ss secretes effector proteins to facilitate invasion into host ...201323459474
molecular diagnostics in a teacup: non-instrumented nucleic acid amplification (nina) for rapid, low cost detection of salmonella enterica.we report on the use of a novel non-instrumented platform to enable a loop mediated isothermal amplification (lamp) based assay for salmonella enterica. heat energy is provided by addition of a small amount (<150 g) of boiling water, and the reaction temperature is regulated by storing latent energy at the melting temperature of a lipid-based engineered phase change material. endpoint classification of the reaction is achieved without opening the reaction tube by observing the fluorescence of se ...201325477717
active modification of host inflammation by salmonella.the dampening of host immune responses is a critical aspect of pathogenesis for the enteropathogen salmonella enterica. our laboratory has recently described a role for the secreted effector gogb in disruption of nfκb activation and limitation of the host inflammatory response to infection. gogb alters the nfκb pathway by preventing iκb degradation by the host scf e3 ubiquitin ligase, through an interaction with skp1 and fbxo22. the prevention of nfκb activation through this interaction dampens ...201323333857
allelic variation in salmonella: an underappreciated driver of adaptation and virulence.salmonella enterica causes substantial morbidity and mortality in humans and animals. infection and intestinal colonization by s. enterica require virulence factors that mediate bacterial binding and invasion of enterocytes and innate immune cells. some s. enterica colonization factors and their alleles are host restricted, suggesting a potential role in regulation of host specificity. recent data also suggest that colonization factors promote horizontal gene transfer of antimicrobial resistance ...201324454310
escherichia coli o157:h7 induces stronger plant immunity than salmonella enterica typhimurium sl1344.consumption of fresh produce contaminated with bacterial human pathogens has resulted in various, sometimes deadly, disease outbreaks. in this study, we assessed plant defense responses induced by the fully pathogenic bacteria escherichia coli o157:h7 and salmonella enterica serovar typhimurium sl1344 in both arabidopsis thaliana and lettuce (lactuca sativa). unlike sl1344, o157:h7 induced strong plant immunity at both pre-invasion and post-invasion steps of infection. for instance, o157:h7 trig ...201323301812
posttranslational maturation of the invasion acyl carrier protein of salmonella enterica serovar typhimurium requires an essential phosphopantetheinyl transferase of the fatty acid biosynthesis pathway.salmonella pathogenicity island 1 (spi-1) carries genes required for the formation of a type 3 secretion system, which is necessary for the invasion process of salmonella. among the proteins encoded by spi-1 is iacp, a homolog of acyl carrier proteins. acyl carrier proteins are mainly involved in fatty acid biosynthesis, and they require posttranslational maturation by addition of a 4'-phosphopantetheine prosthetic group to be functional. in this study, we analyzed iacp maturation in vivo. by pe ...201323893113
genome and transcriptome adaptation accompanying emergence of the definitive type 2 host-restricted salmonella enterica serovar typhimurium pathovar.salmonella enterica serovar typhimurium definitive type 2 (dt2) is host restricted to columba livia (rock or feral pigeon) but is also closely related to s. typhimurium isolates that circulate in livestock and cause a zoonosis characterized by gastroenteritis in humans. dt2 isolates formed a distinct phylogenetic cluster within s. typhimurium based on whole-genome-sequence polymorphisms. comparative genome analysis of dt2 94-213 and s. typhimurium sl1344, dt104, and d23580 identified few differe ...201323982073
the feoc protein leads to high cellular levels of the fe(ii) transporter feob by preventing ftsh protease regulation of feob in salmonella enterica.in the gammaproteobacteria, the feoa, feob, and feoc proteins constitute the feo system, which mediates ferrous iron [fe(ii)] import. of these feo proteins, feob is an inner membrane fe(ii) transporter that is aided by the small protein feoa. however, the role of another small protein, feoc, has remained unknown. here we report that the feoc protein is necessary for feob protein-mediated fe(ii) uptake in salmonella experiencing low levels of oxygen and iron. the feoc protein was found to directl ...201323708131
bacterial colonization of host cells in the absence of cholesterol.reports implicating important roles for cholesterol and cholesterol-rich lipid rafts in host-pathogen interactions have largely employed sterol sequestering agents and biosynthesis inhibitors. because the pleiotropic effects of these compounds can complicate experimental interpretation, we developed a new model system to investigate cholesterol requirements in pathogen infection utilizing dhcr24(-/-) mouse embryonic fibroblasts (mefs). dhcr24(-/-) mefs lack the δ24 sterol reductase required for ...201323358892
comparative sequence, structure and redox analyses of klebsiella pneumoniae dsba show that anti-virulence target dsba enzymes fall into distinct classes.bacterial dsba enzymes catalyze oxidative folding of virulence factors, and have been identified as targets for antivirulence drugs. however, dsba enzymes characterized to date exhibit a wide spectrum of redox properties and divergent structural features compared to the prototypical dsba enzyme of escherichia coli dsba (ecdsba). nonetheless, sequence analysis shows that dsbas are more highly conserved than their known substrate virulence factors, highlighting the potential to inhibit virulence a ...201324244651
salmonella typhi omps1 and omps2 porins are potent protective immunogens with adjuvant properties.salmonella enterica serovar typhi (s. typhi) is the causal agent of typhoid fever, a disease that primarily affects developing countries. various antigens from this bacterium have been reported to be targets of the immune response. recently, the s. typhi genome has been shown to encode two porins--omps1 and omps2--which are expressed at low levels under in vitro culture conditions. in this study, we demonstrate that immunizing mice with either omps1 or omps2 induced production of specific, long- ...201323432484
bacterial coinfections in travelers with malaria: rationale for antibiotic therapy.malaria predisposes children in areas where malaria is endemic to concurrent bacteremia, often with severe outcomes. the importance of bacterial coinfections in patients diagnosed with malaria in nonendemic settings has, however, not been reported. a retrospective analysis of microbiology data was performed in 755 travelers diagnosed with malaria in sweden. bacterial cultures from blood and other locations were correlated to clinical outcome and antibiotic treatment. blood cultures were drawn fr ...201323052321
host specificity of bacterial pathogens.most pathogens are able to infect multiple hosts but some are highly adapted to a single-host species. a detailed understanding of the basis of host specificity can provide important insights into molecular pathogenesis, the evolution of pathogenic microbes, and the potential for pathogens to cross the species barrier to infect new hosts. comparative genomics and the development of humanized mouse models have provided important new tools with which to explore the basis of generalism and speciali ...201324296346
dimethyl adenosine transferase (ksga) deficiency in salmonella enterica serovar enteritidis confers susceptibility to high osmolarity and virulence attenuation in chickens.dimethyl adenosine transferase (ksga) performs diverse roles in bacteria, including ribosomal maturation and dna mismatch repair, and synthesis of ksga is responsive to antibiotics and cold temperature. we previously showed that a ksga mutation in salmonella enterica serovar enteritidis results in impaired invasiveness in human and avian epithelial cells. in this study, we tested the virulence of a ksga mutant (the ksga::tn5 mutant) of s. enteritidis in orally challenged 1-day-old chickens. the ...201324123731
absence of platelet endothelial cell adhesion molecule 1, pecam-1/cd31, in vivo increases resistance to salmonella enterica serovar typhimurium in mice.pecam-1/cd31 is known to regulate inflammatory responses and exhibit pro- and anti-inflammatory functions. this study was designed to determine the functional role of pecam-1 in susceptibility to murine primary in vivo infection with salmonella enterica serovar typhimurium and in in vitro inflammatory responses of peritoneal macrophages. lectin profiling showed that cellular pecam-1 and recombinant human pecam-1-ig chimera contain high levels of mannose sugars and n-acetylglucosamine. consistent ...201323509149
computational analysis of bacterial rna-seq data.recent advances in high-throughput rna sequencing (rna-seq) have enabled tremendous leaps forward in our understanding of bacterial transcriptomes. however, computational methods for analysis of bacterial transcriptome data have not kept pace with the large and growing data sets generated by rna-seq technology. here, we present new algorithms, specific to bacterial gene structures and transcriptomes, for analysis of rna-seq data. the algorithms are implemented in an open source software system c ...201323716638
rapid sample processing for detection of food-borne pathogens via cross-flow microfiltration.this paper reports an approach to enable rapid concentration and recovery of bacterial cells from aqueous chicken homogenates as a preanalytical step of detection. this approach includes biochemical pretreatment and prefiltration of food samples and development of an automated cell concentration instrument based on cross-flow microfiltration. a polysulfone hollow-fiber membrane module having a nominal pore size of 0.2 μm constitutes the core of the cell concentration instrument. the aqueous chic ...201324014538
detection of salmonella spp, salmonella enteritidis and typhimurium in naturally infected broiler chickens by a multiplex pcr-based assay.the presence of salmonella in the intestinal tract, on the chickens skin and among their feathers, may cause carcasses contamination during slaughtering and processing and possibly it is responsible by the introduction of this microorganism in the slaughterhouses. a rapid method to identify and monitor salmonella and their sorovars in farm is becoming necessary. a pre-enriched multiplex polymerase chain reaction (m-pcr) assay employing specific primers was developed and used to detect salmonella ...201324159281
ompw is cooperatively upregulated by mara and soxs in response to menadione.ompw is a minor porin whose biological function has not been clearly defined. evidence obtained in our laboratory indicates that in salmonella enterica serovar typhimurium the expression of ompw is activated by soxs upon exposure to paraquat and it is required for resistance. soxs belongs to the arac family of transcriptional regulators, like mara and rob. due to their high structural similarity, the genes under their control have been grouped in the mar/sox/rob regulon, which presents a dna-bin ...201323393149
posttranslational modification of flagellin flab in shewanella oneidensis.shewanella oneidensis is a highly motile organism by virtue of a polar, glycosylated flagellum composed of flagellins flaa and flab. in this study, the functional flagellin flab was isolated and analyzed with nano-liquid chromatography-mass spectrometry (ms) and tandem ms. in combination with the mutational analysis, we propose that the flab flagellin protein from s. oneidensis is modified at five serine residues with a series of novel o-linked posttranslational modifications (ptms) that differ ...201323543712
ramr mutations affecting fluoroquinolone susceptibility in epidemic multidrug-resistant salmonella enterica serovar kentucky st198.a screening for non-target mutations affecting fluoroquinolone susceptibility was conducted in epidemic multidrug-resistant salmonella enterica serovar kentucky st198. among a panel of representative isolates (n = 27), covering the epidemic, only three showed distinct mutations in ramr resulting in enhanced expression of genes encoding the acrab-tolc efflux system and low increase in ciprofloxacin mic. no mutations were detected in other regulatory regions of this efflux system. ciprofloxacin re ...201323914184
the virulence of salmonella typhimurium in the insect model galleria mellonella is impaired by mutations in endoribonucleases e and iii.salmonella enterica serovar typhimurium is a gram-negative bacterium able to invade and replicate inside eukaryotic cells. to cope with the host defense mechanisms, the bacterium has to rapidly remodel its transcriptional status. regulatory rnas and ribonucleases are the factors that ultimately control the fate of mrnas and final protein levels in the cell. there is growing evidence of the direct involvement of these factors in bacterial pathogenicity. in this report, we validate the use of gall ...201323913419
infectious diseases in humanized mice.despite many theoretical incompatibilities between mouse and human cells, mice with reconstituted human immune system components contain nearly all human leukocyte populations. accordingly, several human-tropic pathogens have been investigated in these in vivo models of the human immune system, including viruses such as human immunodeficiency virus (hiv) and epstein barr virus (ebv), as well as bacteria such as mycobacterium tuberculosis (mtb) and salmonella enterica typhi (s. typhi). while thes ...201323913412
evaluation of the immunogenicity of campylobacter jejuni cjaa protein delivered by salmonella enterica sv. typhimurium strain with regulated delayed attenuation in chickens.campylobacter spp. are regarded as the most common bacterial cause of gastroenteritis worldwide, and consumption of chicken meat contaminated by campylobacter is considered to be one of the most frequent sources of human infection in developed countries. here we evaluated the immunogenicity and protective efficacy of salmonella typhimurium χ9718 producing the campylobacter jejuni cjaa protein as a chicken anti-campylobacter vaccine. in this study chickens were orally immunized with a new generat ...201323913025
on-chip microbial culture for the specific detection of very low levels of bacteria.microbial culture continues to be the most common protocol for bacterial detection and identification in medicine and agronomics. using this process may take days to identify a specific pathogen for most bacterial strains. surface plasmon resonance (spr) detection is an emerging alternative technology that can be used for the detection of bacteria using protein microarrays although typical limits of detection are in the range of 10(3)-10(6) cfu ml(-1), which is not compatible with most food safe ...201323912527
wksl3, a new biocontrol agent for salmonella enterica serovars enteritidis and typhimurium in foods: characterization, application, sequence analysis, and oral acute toxicity study.of the salmonella enterica serovars, s. enteritidis and s. typhimurium are responsible for most of the salmonella outbreaks implicated in the consumption of contaminated foods in the republic of korea. because of the widespread occurrence of antimicrobial-resistant salmonella in foods and food processing environments, bacteriophages have recently surfaced as an alternative biocontrol tool. in this study, we isolated a virulent bacteriophage (wksl3) that could specifically infect s. enteritidis, ...201323335772
a prospective study of the causes of febrile illness requiring hospitalization in children in cambodia.febrile illnesses are pre-eminent contributors to morbidity and mortality among children in south-east asia but the causes are poorly understood. we determined the causes of fever in children hospitalised in siem reap province, cambodia.201323593267
first trimester typhoid fever with vertical transmission of salmonella typhi, an intracellular organism.we report a case in which placental abruption occurred at 16 weeks following first trimester diagnosis and treatment for typhoid fever. unexpectedly salmonella enterica serovar typhi (s. typhi) was found in fetal tissues at autopsy. using information from the murine model of typhoid fever in pregnancy, we draw parallels between s. typhi and l. monocytogenes to develop a plausible hypothesis to explain how this organism was able to cross the placenta in the first trimester to cause abruption, inf ...201324459469
common evolutionary origin for the rotor domain of rotary atpases and flagellar protein export apparatus.the v1- and f1- rotary atpases contain a rotor that rotates against a catalytic a3b3 or α3β3 stator. the rotor f(1-γ) or v1-df is composed of both anti-parallel coiled coil and globular-loop parts. the bacterial flagellar type iii export apparatus contains a v1/f1-like atpase ring structure composed of flii6 homo-hexamer and flij which adopts an anti-parallel coiled coil structure without the globular-loop part. here we report that flij of salmonella enterica serovar typhimurium shows a rotor li ...201323724081
identification of salmonella enterica serovar pullorum antigenic determinants expressed in vivo.salmonella enterica serovar pullorum affecting poultry causes pullorum disease and results in severe economic loss in the poultry industry. currently, it remains a major threat in countries with poor poultry surveillance and no efficient control measures. as s. pullorum could induce strong humoral immune responses, we applied an immunoscreening technique, the in vivo-induced antigen technology (iviat), to identify immunogenic bacterial proteins expressed or upregulated during s. pullorum infecti ...201323774596
il-10 produced by trophoblast cells inhibits phagosome maturation leading to profound intracellular proliferation of salmonella enterica typhimurium.salmonella enterica typhimurium (st) is a phagosomal pathogen that can infect placental trophoblast cells leading to abortion and severe maternal illness. it is unclear how the trophoblast cells promote profound bacterial proliferation.201323834952
attenuating gene expression (age) for vaccine development.live attenuated vaccines are adept in stimulating protective immunity. methods for generating such vaccines have largely adopted strategies used with salmonella enterica. yet, when similar strategies were tested in other gram-negative bacteria, the virulence factors or genes responsible to incapacitate salmonella often failed in providing the desired outcome. consequently, conventional live vaccines rely on prior knowledge of the pathogen's virulence factors to successfully attenuate them. this ...201323652809
the ferric enterobactin transporter fep is required for persistent salmonella enterica serovar typhimurium infection.most bacterial pathogens require iron to grow and colonize host tissues. the gram-negative bacterium salmonella enterica serovar typhimurium causes a natural systemic infection of mice that models acute and chronic human typhoid fever. s. typhimurium resides in tissues within cells of the monocyte lineage, which limit pathogen access to iron, a mechanism of nutritional immunity. the primary ferric iron import system encoded by salmonella is the siderophore abc transporter fepbdgc. the fep system ...201323959718
salmonella infection induces recruitment of caspase-8 to the inflammasome to modulate il-1β production.nucleotide-binding oligomerization domain-like receptors (nlrs) detect pathogens and danger-associated signals within the cell. salmonella enterica serovar typhimurium, an intracellular pathogen, activates caspase-1 required for the processing of the proinflammatory cytokines, pro-il-1β and pro-il-18, and pyroptosis. in this study, we show that salmonella infection induces the formation of an apoptosis-associated specklike protein containing a card (asc)-caspase-8-caspase-1 inflammasome in macro ...201324123685
the type vi secretion system encoded in salmonella pathogenicity island 19 is required for salmonella enterica serotype gallinarum survival within infected macrophages.salmonella enterica serotype gallinarum is the causative agent of fowl typhoid, a disease characterized by high morbidity and mortality that causes major economic losses in poultry production. we have reported that s. gallinarum harbors a type vi secretion system (t6ss) encoded in salmonella pathogenicity island 19 (spi-19) that is required for efficient colonization of chicks. in the present study, we aimed to characterize the spi-19 t6ss functionality and to investigate the mechanisms behind t ...201323357385
pathogenicity of yersinia pestis synthesis of 1-dephosphorylated lipid a.synthesis of escherichia coli lpxl, which transfers a secondary laurate chain to the 2' position of lipid a, in yersinia pestis produced bisphosphoryl hexa-acylated lipid a at 37°c, leading to significant attenuation of virulence. our previous observations also indicated that strain χ10015(pcd1ap) (δlpxp32::p(lpxl) lpxl) stimulated a strong inflammatory reaction but sickened mice before recovery and retained virulence via intranasal (i.n.) infection. the development of live, attenuated y. pestis ...201323357387
the many uses of autophagosomes.autophagy has emerged as a significant innate immune response to pathogens. typically, autophagosomes deliver their contents to lysosomes for degradation. some pathogens such as salmonella enterica serovar typhimurium succumb to autophagy and are transported to lysosomes for degradation. yet, many professional pathogens, including legionella pneumophila and burkholderia cenocepacia, subvert this pathway exploiting autophagy to their advantage.201323507956
interferon-γ- and glucocorticoid-mediated pathways synergize to enhance death of cd4(+) cd8(+) thymocytes during salmonella enterica serovar typhimurium infection.thymic atrophy is known to occur during infections; however, there is limited understanding of its causes and of the cross-talk between different pathways. this study investigates mechanisms involved in thymic atrophy during a model of oral infection by salmonella enterica serovar typhimurium (s. typhimurium). significant death of cd4(+) cd8(+) thymocytes, but not of single-positive thymocytes or peripheral lymphocytes, is observed at later stages during infection with live, but not heat-killed, ...201323186527
expression divergence between escherichia coli and salmonella enterica serovar typhimurium reflects their lifestyles.escherichia coli k12 is a commensal bacteria and one of the best-studied model organisms. salmonella enterica serovar typhimurium, on the other hand, is a facultative intracellular pathogen. these two prokaryotic species can be considered related phylogenetically, and they share a large amount of their genetic material, which is commonly termed the "core genome." despite their shared core genome, both species display very different lifestyles, and it is unclear to what extent the core genome, ap ...201323427276
immune profiling with a salmonella typhi antigen microarray identifies new diagnostic biomarkers of human typhoid.current serological diagnostic assays for typhoid fever are based on detecting antibodies against salmonella lps or flagellum, resulting in a high false-positive rate. here we used a protein microarray containing 2,724 salmonella enterica serovar typhi antigens (>63% of proteome) and identified antibodies against 16 igg antigens and 77 igm antigens that were differentially reactive among acute typhoid patients and healthy controls. the igg target antigens produced a sensitivity of 97% and specif ...201323304434
phylogenomic analysis identifies gene gains that define salmonella enterica subspecies i.comparative methods for analyzing whole genome sequence (wgs) data enable us to assess the genetic information available for reconstructing the evolutionary history of pathogens. we used the comparative approach to determine diagnostic genes for salmonella enterica subspecies i. s. enterica subsp. i strains are known to infect warm-blooded organisms regularly while its close relatives tend to infect only cold-blooded organisms. we found 71 genes gained by the common ancestor of salmonella enteri ...201324204679
salmonella utilizes d-glucosaminate via a mannose family phosphotransferase system permease and associated enzymes.salmonella enterica is a globally significant bacterial food-borne pathogen that utilizes a variety of carbon sources. we report here that salmonella enterica subsp. enterica serovar typhimurium (s. typhimurium) uses d-glucosaminate (2-amino-2-deoxy-d-gluconic acid) as a carbon and nitrogen source via a previously uncharacterized mannose family phosphotransferase system (pts) permease, and we designate the genes encoding the permease dgaabcd (d-glucosaminate pts permease components eiia, eiib, e ...201323836865
epithelial cells augment barrier function via activation of the toll-like receptor 2/phosphatidylinositol 3-kinase pathway upon recognition of salmonella enterica serovar typhimurium curli fibrils in the gut.curli fibrils, the best-characterized functional bacterial amyloids, are an important component of enterobacterial biofilms. we have previously shown that curli fibrils are recognized by the toll-like receptor 2 (tlr2)/tlr1 heterodimer complex. utilizing polarized t-84 cells, an intestinal epithelial cell line derived from colon carcinoma grown on semipermeable tissue culture inserts, we determined that infection with a salmonella enterica serovar typhimurium csgba mutant, which does not express ...201323208603
the salmonella transcriptome in lettuce and cilantro soft rot reveals a niche overlap with the animal host intestine.fresh vegetables have been recurrently associated with salmonellosis outbreaks, and salmonella contamination of retail produce has been correlated positively with the presence of soft rot disease. we observed that population sizes of salmonella enterica serovar typhimurium sl1344 increased 56-fold when inoculated alone onto cilantro leaves, versus 2,884-fold when coinoculated with dickeya dadantii, a prevalent pathogen that macerates plant tissue. a similar trend in s. enterica populations was o ...201323104408
loss of culturability of salmonella enterica subsp. enterica serovar typhimurium upon cell-cell contact with human fecal bacteria.loss of culturability of salmonella enterica subsp. enterica serovar typhimurium has been observed in mixed cultures with anaerobic fecal bacteria under conditions that allow local interaction between cells, such as cell contact. a reduction of a population of culturable s. typhimurium on the order of ∼10(4) to 10(5) cfu/ml was observed in batch anaerobic mixed cultures with fecal samples from different human donors. culturability was not affected either in supernatants collected at several time ...201323503308
impact of plasmids, including those encodingvirb4/d4 type iv secretion systems, on salmonella enterica serovar heidelberg virulence in macrophages and epithelial cells.salmonella enterica serovar heidelberg (s. heidelberg) can cause foodborne illness in humans following the consumption of contaminated meat and poultry products. recent studies from our laboratory have demonstrated that certain s. heidelberg isolated from food-animal sources harbor multiple transmissible plasmids with genes that encode antimicrobial resistance, virulence and a virb4/d4 type-iv secretion system. this study examines the potential role of these transmissible plasmids in bacterial u ...201324098597
evaluation of a simple blood culture amplification and antigen detection method for diagnosis of salmonella enterica serovar typhi bacteremia.in most areas where typhoid is endemic, laboratory diagnosis is not possible due to the lack of appropriate facilities. we investigated whether the combination of blood culture amplification of salmonella enterica serovar typhi with an s. typhi antigen rapid diagnostic test (rdt) could be an accurate and inexpensive tool for the accelerated diagnosis of patients with acute typhoid in laos. for a panel of 23 gram-negative reference pathogens, the standard diagnostics (catalog no. 15fk20; kyonggi- ...201323100346
competition for zinc binding in the host-pathogen interaction.due to its favorable chemical properties, zinc is used as a structural or catalytic cofactor in a very large number of proteins. despite the apparent abundance of this metal in all cell types, the intracellular pool of loosely bound zinc ions available for biological exchanges is in the picomolar range and nearly all zinc is tightly bound to proteins. in addition, to limit bacterial growth, some zinc-sequestering proteins are produced by eukaryotic hosts in response to infections. therefore, to ...201324400228
fitness benefits in fluoroquinolone-resistant salmonella typhi in the absence of antimicrobial pressure.fluoroquinolones (fq) are the recommended antimicrobial treatment for typhoid, a severe systemic infection caused by the bacterium salmonella enterica serovar typhi. fq-resistance mutations in s. typhi have become common, hindering treatment and control efforts. using in vitro competition experiments, we assayed the fitness of eleven isogenic s. typhi strains with resistance mutations in the fq target genes, gyra and parc. in the absence of antimicrobial pressure, 6 out of 11 mutants carried a s ...201324327559
salmonella pathogenicity and host adaptation in chicken-associated serovars.enteric pathogens such as salmonella enterica cause significant morbidity and mortality. s. enterica serovars are a diverse group of pathogens that have evolved to survive in a wide range of environments and across multiple hosts. s. enterica serovars such as s. typhi, s. dublin, and s. gallinarum have a restricted host range, in which they are typically associated with one or a few host species, while s. enteritidis and s. typhimurium have broad host ranges. this review examines how s. enterica ...201324296573
the abc-type efflux pump macab protects salmonella enterica serovar typhimurium from oxidative stress.multidrug efflux pumps are integral membrane proteins known to actively excrete antibiotics. the macrolide-specific pump macab, the only abc-type drug efflux pump in salmonella, has previously been linked to virulence in mice. the molecular mechanism of this link between macab and infection is unclear. we demonstrate that macab plays a role in the detoxification of reactive oxygen species (ros), compounds that salmonellae are exposed to at various stages of infection. macab is induced upon expos ...201324169575
sandwich assay for mixed-sequence recognition of double-stranded dna: invader-based detection of targets specific to foodborne pathogens.a 96-well plate sandwich assay based on invader capture/signalling probes is used to recognize 28-mer mixed-sequence dsdna targets specific to salmonella enterica, campylobacter jejuni, escherichia coli. targets are detected down to 20-55 pm concentration with excellent binding specificity.201324036937
the mucin muc2 limits pathogen burdens and epithelial barrier dysfunction during salmonella enterica serovar typhimurium colitis.salmonella enterica serovar typhimurium is a model organism used to explore the virulence strategies underlying salmonella pathogenesis. although intestinal mucus is the first line of defense in the intestine, its role in protection against salmonella is still unclear. the intestinal mucus layer is composed primarily of the muc2 mucin, a heavily o-glycosylated glycoprotein. the core 3-derived o-glycans of muc2 are synthesized by core 3 β1,3-n-acetylglucosaminyltransferase (c3gnt). mice lacking t ...201323876803
survey of culture, goldengate assay, universal biosensor assay, and 16s rrna gene sequencing as alternative methods of bacterial pathogen detection.cultivation-based assays combined with pcr or enzyme-linked immunosorbent assay (elisa)-based methods for finding virulence factors are standard methods for detecting bacterial pathogens in stools; however, with emerging molecular technologies, new methods have become available. the aim of this study was to compare four distinct detection technologies for the identification of pathogens in stools from children under 5 years of age in the gambia, mali, kenya, and bangladesh. the children were ide ...201323884998
structure and function of the salmonella typhi chimaeric a(2)b(5) typhoid toxin.salmonella enterica serovar typhi (s. typhi) differs from most other salmonellae in that it causes a life-threatening systemic infection known as typhoid fever. the molecular bases for its unique clinical presentation are unknown. here we find that the systemic administration of typhoid toxin, a unique virulence factor of s. typhi, reproduces many of the acute symptoms of typhoid fever in an animal model. we identify specific carbohydrate moieties on specific surface glycoproteins that serve as ...201323842500
igg subclass antibodies to human and bacterial hsp60 are not associated with disease activity and progression over time in axial spondyloarthritis.spondyloarthritis (spa), an interrelated group of rheumatic diseases, has been suggested to be triggered by bacterial infections prior to the development of an autoimmune response that causes inflammation of the spinal and peripheral joints. because human heat shock protein 60 (hsp60), recently renamed hspd1, and bacterial hsp60 are highly homologous, immunological cross-reactivity has been proposed as a mechanism of disease initiation. however, previous investigations of the humoral immune resp ...201323705835
genetic mechanisms of antimicrobial resistance identified in salmonella enterica, escherichia coli, and enteroccocus spp. isolated from u.s. food animals.the prevalence of antimicrobial resistance (ar) in bacteria isolated from u.s. food animals has increased over the last several decades as have concerns of ar foodborne zoonotic human infections. resistance mechanisms identified in u.s. animal isolates of salmonella enterica included resistance to aminoglycosides (e.g., alleles of aacc, aada, aadb, ant, apha, and strab), β-lactams (e.g., bla cmy-2, tem-1, pse-1), chloramphenicol (e.g., flor, cmla, cat1, cat2), folate pathway inhibitors (e.g., al ...201323734150
salmonella uses energy taxis to benefit from intestinal inflammation.chemotaxis enhances the fitness of salmonella enterica serotype typhimurium (s. typhimurium) during colitis. however, the chemotaxis receptors conferring this fitness advantage and their cognate signals generated during inflammation remain unknown. here we identify respiratory electron acceptors that are generated in the intestinal lumen as by-products of the host inflammatory response as in vivo signals for methyl-accepting chemotaxis proteins (mcps). three mcps, including trg, tsr and aer, enh ...201323637594
bacterial and viral etiology of childhood diarrhea in ouagadougou, burkina faso.diarrhea is the most frequent health problem among children in developing countries. this study investigated the bacterial and viral etiology and related clinical and epidemiological factors in children with acute diarrhea in ouagadougou, burkina faso.201323506294
electrochemical detection of salmonella using gold nanoparticles.a disposable immunosensor for salmonella enterica subsp. enterica serovar typhimurium lt2 (s) detection using a magneto-immunoassay and gold nanoparticles (aunps) as label for electrochemical detection is developed. the immunosensor is based on the use of a screen-printed carbon electrode (spce) that incorporates a permanent magnet underneath. salmonella containing samples (i.e. skimmed milk) have been tested by using anti-salmonella magnetic beads (mbs-psab) as capture phase and sandwiching aft ...201322884647
identification of salmonella pathogenicity island-2 type iii secretion system effectors involved in intramacrophage replication of s. enterica serovar typhimurium: implications for rational vaccine design.salmonella enterica serovars cause severe diseases in humans, such as gastroenteritis and typhoid fever. the development of systemic disease is dependent on a type iii secretion system (t3ss) encoded by salmonella pathogenicity island-2 (spi-2). translocation of effector proteins across the salmonella-containing vacuole, via the spi-2 t3ss, enables bacterial replication within host cells, including macrophages. here, we investigated the contribution of these effectors to intramacrophage replicat ...201323592259
effects of pesticides on the reduction of plant and human pathogenic bacteria in application water.overhead spray applications of in-field tomato treatments dissolved in aqueous solutions have specific pest targets (fungal, bacterial, insect, or other). any organism present in the solution or on treated plant surfaces that is not a specific target of the application is unlikely inactivated and can instead be spread through the phyllosphere. in this laboratory study, commercially labeled pesticides (including actigard 50wg, bravo weather stik 6f, cabrio 20eg, kasumin, kocide 3000 46wg, oxidate ...201323575141
dnase i and proteinase k eliminate dna from injured or dead bacteria but not from living bacteria in microbial reference systems and natural drinking water biofilms for subsequent molecular biology analyses.molecular techniques, such as polymerase chain reaction (pcr) and quantitative pcr (qpcr), are very sensitive, but may detect total dna present in a sample, including extracellular dna (edna) and dna coming from live and dead cells. dnase i is an endonuclease that non-specifically cleaves single- and double-stranded dna. this enzyme was tested in this study to analyze its capacity of digesting dna coming from dead cells with damaged cell membranes, leaving dna from living cells with intact cell ...201323811209
species-dependent blood-brain barrier disruption of lipopolysaccharide: amelioration by colistin in vitro and in vivo.the aim of this study was to use in vitro and in vivo models to assess the impact of lipopolysaccharide (lps) from two different bacterial species on blood-brain barrier (bbb) integrity and brain uptake of colistin. following repeated administration of lps from pseudomonas aeruginosa, the brain-to-plasma ratio of [(14)c]sucrose in swiss outbred mice was not significantly increased. furthermore, while the brain uptake of colistin in mice increased 3-fold following administration of lps from salmo ...201323796941
extracellular dna-induced antimicrobial peptide resistance in salmonella enterica serovar typhimurium.the salmonella enterica serovar typhimurium phopq two component system (tcs) is activated by low mg2+ levels, low ph and by antimicrobial peptides (ap). under mg2+ limitation, the phopq system induces pmrd expression, which post-translationally activates the pmrab tcs. phopq and pmrab control many genes required for intracellular survival and pathogenesis. these include the polymyxin resistance (pmr) operon, which is required for aminoarabinose modification of lps and protecting the outer membra ...201323705831
formation of biofilms under phage predation: considerations concerning a biofilm increase.bacteriophages are emerging as strong candidates for combating bacterial biofilms. however, reports indicating that host populations can, in some cases, respond to phage predation by an increase in biofilm formation are of concern. this study investigates whether phage predation can enhance the formation of biofilm and if so, if this phenomenon is governed by the emergence of phage-resistance or by non-evolutionary mechanisms (eg spatial refuge). single-species biofilms of three bacterial pathog ...201323597188
the calcium-stimulated lipid a 3-o deacylase from rhizobium etli is not essential for plant nodulation.the lipid a component of lipopolysaccharide from the nitrogen-fixing plant endosymbiont, rhizobium etli, is structurally very different from that found in most enteric bacteria. the lipid a from free-living r. etli is structurally heterogeneous and exists as a mixture of species which are either pentaacylated or tetraacylated. in contrast, the lipid a from r. etli bacteroids is reported to consist exclusively of tetraacylated lipid a species. the tetraacylated lipid a species in both cases lack ...201324046865
nasal vaccination with attenuated salmonella expressing vapa: tlr2 activation is not essential for protection against r. equi infection.virulent strains of rhodococcus equi have a large plasmid of 80-90kb, which encodes several virulence-associated proteins (vap), including vapa, a lipoprotein highly associated with disease. we have previously demonstrated that oral immunisation with attenuated salmonella enterica typhimurium strain expressing the antigen vapa (stm vapa+) induces specific and long-term humoral and cellular immunity against r. equi. it was shown that vapa activates toll-like receptor 2 (tlr2) on macrophages by es ...201323933366
emergence of salmonella genomic island 1 (sgi1) among proteus mirabilis clinical isolates in dijon, france.salmonella genomic island 1 (sgi1) is often encountered in antibiotic-resistant salmonella enterica and exceptionally in proteus mirabilis. we investigated the prevalence of sgi1-producing clinical isolates of p. mirabilis in our hospital (dijon, france).201323580563
porcine circovirus type 2 (pcv2) vaccination reduces pcv2 in a pcv2 and salmonella enterica serovar choleraesuis coinfection model.we previously reported that prior porcine circovirus type 2 (pcv2) infection potentiates the severity of clinical signs, lung lesions, and fecal shedding and tissue dissemination of salmonella enterica serovar choleraesuis in infected pigs. here, we evaluated whether pcv2 vaccination is effective in reducing fecal shedding and tissue dissemination of s. choleraesuis and improving clinical signs associated with pcv2 and s. choleraesuis infection in 15 cesarean-derived, colostrum-deprived pigs ran ...201323107657
antigenicity and immunogenicity of plasmodium vivax merozoite surface protein-3.a recent clinical trial in african children demonstrated the potential utility of merozoite surface protein (msp)-3 as a vaccine against plasmodium falciparum malaria. the present study evaluated the use of plasmodium vivax msp-3 (pvmsp-3) as a target antigen in vaccine formulations against malaria caused by p. vivax. recombinant proteins representing msp-3α and msp-3β of p. vivax were expressed as soluble histidine-tagged bacterial fusions. antigenicity during natural infection was evaluated by ...201323457498
resident bacteria on leaves enhance survival of immigrant cells of salmonella enterica.although salmonella enterica apparently has comparatively low epiphytic fitness on plants, external factors that would influence its ability to survive on plants after contamination would be of significance in the epidemiology of human diseases caused by this human pathogen. viable population sizes of s. enterica applied to plants preinoculated with pseudomonas syringae or either of two erwinia herbicola strains was ≥10-fold higher than that on control plants that were not precolonized by such i ...201323506362
the ubiquitin ligase parkin mediates resistance to intracellular pathogens.ubiquitin-mediated targeting of intracellular bacteria to the autophagy pathway is a key innate defence mechanism against invading microbes, including the important human pathogen mycobacterium tuberculosis. however, the ubiquitin ligases responsible for catalysing ubiquitin chains that surround intracellular bacteria are poorly understood. the parkin protein is a ubiquitin ligase with a well-established role in mitophagy, and mutations in the parkin gene (park2) lead to increased susceptibility ...201324005326
immune-responsive gene 1 protein links metabolism to immunity by catalyzing itaconic acid production.immunoresponsive gene 1 (irg1) is highly expressed in mammalian macrophages during inflammation, but its biological function has not yet been elucidated. here, we identify irg1 as the gene coding for an enzyme producing itaconic acid (also known as methylenesuccinic acid) through the decarboxylation of cis-aconitate, a tricarboxylic acid cycle intermediate. using a gain-and-loss-of-function approach in both mouse and human immune cells, we found irg1 expression levels correlating with the amount ...201323610393
horizontally acquired glycosyltransferase operons drive salmonellae lipopolysaccharide diversity.the immunodominant lipopolysaccharide is a key antigenic factor for gram-negative pathogens such as salmonellae where it plays key roles in host adaptation, virulence, immune evasion, and persistence. variation in the lipopolysaccharide is also the major differentiating factor that is used to classify salmonella into over 2600 serovars as part of the kaufmann-white scheme. while lipopolysaccharide diversity is generally associated with sequence variation in the lipopolysaccharide biosynthesis op ...201323818865
evolutionary genomics of salmonella enterica subspecies.abstract six subspecies are currently recognized in salmonella enterica. subspecies i (subspecies enterica) is responsible for nearly all infections in humans and warm-blooded animals, while five other subspecies are isolated principally from cold-blooded animals. we sequenced 21 phylogenetically diverse strains, including two representatives from each of the previously unsequenced five subspecies and 11 diverse new strains from s. enterica subspecies enterica, to put this species into an evolut ...201323462113
efficacy of integrated treatment of uv light and low-dose gamma irradiation on inactivation of escherichia coli o157:h7 and salmonella enterica on grape tomatoes.the study evaluated the efficacy of integrated ultraviolet-c light (uvc) and low-dose gamma irradiation treatments to inactivate mixed strains of escherichia coli o157:h7 and salmonella enterica on inoculated whole grape tomatoes. a mixed bacterial cocktail composed of a 3 strain mixture of e. coli o157:h7 (c9490, e02128, and f00475) and a 3 serotype mixture of s. enterica (s. montevideo g4639, s. newport h1275, and s. stanley h0558) was used based on their association with produce-related outbr ...201323701667
bacterial tir-containing proteins and host innate immune system evasion.the innate immune system provides the first line of host defence against invading pathogens. key to upregulation of the innate immune response are toll-like receptors (tlrs), which recognize pathogen-associated molecular patterns (pamps) and trigger a signaling pathway culminating in the production of inflammatory mediators. central to this tlr signaling pathway are heterotypic protein-protein interactions mediated through toll/interleukin-1 receptor (tir) domains found in both the cytoplasmic r ...201322772799
prevalence, antimicrobial resistance and relation to indicator and pathogenic microorganisms of salmonella enterica isolated from surface waters within an agricultural landscape.during a 12 month period (june 2007-may 2008), the prevalence and susceptibility of salmonella serovars and their relation to specific pathogenic and indicator bacteria in river and coastal waters was investigated. a total of 240 water samples were collected from selected sites in acheron and kalamas rivers and the ionian sea coast in north western greece. the samples were analyzed for salmonella spp., listeria spp., campylobacter spp., escherichia coli o157, staphylococci, pseudomonas spp., tot ...201322901425
manipulation of innate immunity by a bacterial secreted peptide: lantibiotic nisin z is selectively immunomodulatory.innate immunity is triggered by a variety of bacterial molecules, resulting in both protective and potentially harmful pro-inflammatory responses. further, innate immunity also provides a mechanism for the maintenance of homeostasis between the host immune system and symbiotic or non-pathogenic microorganisms. however, the bacterial factors that mediate these protective effects have been incompletely defined. here, it was demonstrated that the lantiobiotic nisin z is able to modulate host immune ...201323109507
persistence and leaching potential of microorganisms and mineral n in animal manure applied to intact soil columns.pathogens may reach agricultural soils through application of animal manure and thereby pose a risk of contaminating crops as well as surface and groundwater. treatment and handling of manure for improved nutrient and odor management may also influence the amount and fate of manure-borne pathogens in the soil. a study was conducted to investigate the leaching potentials of a phage (salmonella enterica serovar typhimurium bacteriophage 28b) and two bacteria, escherichia coli and enterococcus spec ...201323124240
glycoengineering of host mimicking type-2 lacnac polymers and lewis x antigens on bacterial cell surfaces.bacterial carbohydrate structures play a central role in mediating a variety of host-pathogen interactions. glycans can either elicit protective immune response or lead to escape of immune surveillance by mimicking host structures. lipopolysaccharide (lps), a major component on the surface of gram-negative bacteria, is composed of a lipid a-core and the o-antigen polysaccharide. pathogens like neisseria meningitidis expose a lipooligosaccharide (los), which outermost glycans mimick mammalian epi ...201323163552
landscape and meteorological factors affecting prevalence of three food-borne pathogens in fruit and vegetable farms.produce-related outbreaks have been traced back to the preharvest environment. a longitudinal study was conducted on five farms in new york state to characterize the prevalence, persistence, and diversity of food-borne pathogens in fresh produce fields and to determine landscape and meteorological factors that predict their presence. produce fields were sampled four times per year for 2 years. a total of 588 samples were analyzed for listeria monocytogenes, salmonella, and shiga toxin-producing ...201323144137
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