Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
characterisation of pathogenic bacteria in a uasb-polishing pond system using molecular techniques.molecular techniques have been commonly used to detect and quantify pathogenic bacteria in food, clinical and environmental samples, but in wastewater treatment plants few studies have been carried out. this work applied pcr with a specific set of primers to investigate pathogenic bacteria in a wastewater plant comprised of a uasb reactor followed by polishing ponds. in addition, in-situ hybridisation technique (fish) was used to estimate the abundance of escherichia coli in the system. accordin ...201020150719
molecular basis for endotoxin neutralization by amphipathic peptides derived from the alpha-helical cationic core-region of nk-lysin.an analysis of the interaction of the nk-lysin derived peptide nk-2 and of analogs thereof with bacterial lipopolysaccharide (lps, endotoxin) was performed to determine the most important biophysical parameters for an effective lps neutralization. we used microcalorimetry, ftir spectroscopy, zeta potential measurements, and small-angle x-ray scattering to analyze the peptide:lps binding enthalpy, the accessible lps surface charge, the fluidity of the lps hydrocarbon chains, their phase transitio ...201020153101
protecting against antimicrobial effectors in the phagosome allows sodcii to contribute to virulence in salmonella enterica serovar typhimurium.salmonella enterica serovar typhimurium replicates in macrophages, where it is subjected to antimicrobial substances, including superoxide, antimicrobial peptides, and proteases. the bacterium produces two periplasmic superoxide dismutases, sodci and sodcii. although both are expressed during infection, only sodci contributes to virulence in the mouse by combating phagocytic superoxide. the differential contribution to virulence is at least partially due to inherent differences in the sodci and ...201020154132
the second extracellular loop of pore-forming subunits of atp-binding cassette transporters for basic amino acids plays a crucial role in interaction with the cognate solute binding protein(s).in the thermophile geobacillus stearothermophilus, the uptake of basic amino acids is mediated by an abc transporter composed of the substrate binding protein (receptor) artj and a homodimer each of the pore-forming subunit, artm, and the nucleotide-binding subunit, artp. we recently identified two putative binding sites in artj that might interact with the art(mp)(2) complex, thereby initiating the transport cycle (a. vahedi-faridi et al., j. mol. biol. 375:448-459, 2008). here we investigated ...201020154136
the occurrence and sources of campylobacter spp., salmonella enterica and escherichia coli o157:h7 in the salmon river, british columbia, canada.in this study, we wished to assess the prevalence and determine the sources of three zoonotic bacterial pathogens (salmonella, campylobacter, and escherichia coli o157:h7) in the salmon river watershed in southwestern british columbia. surface water, sewage, and animal faecal samples were collected from the watershed. selective bacterial culture and pcr techniques were used to isolate these three pathogens and indicator bacteria from these samples and characterize them. campylobacter was the mos ...201020154400
eric pcr and rapd based fingerprinting of salmonella typhi strains isolated over a period of two decades.salmonella enterica serotype typhi strains (n=113) were isolated from typhoid patients over a period of 2 decades, i.e. 1987-2006. rapd and eric pcr methods were used for random whole genome typing of these strains. eric pcr was found to be very efficient with the discriminatory index (di) of 0.9821 with 100% reproducibility. rapd was satisfactory in discriminating the strains (di=0.8978) but with poor reproducibility (40%). however, composite genotypic analysis was still better with di of 0.998 ...201020156601
virulence mechanisms displayed by salmonella to impair dendritic cell function.dendritic cells (dcs) link innate and adaptive immunity by directly recognizing pathogen-associated molecular patterns (pamps) on bacteria. dcs can capture and degrade bacteria and present their antigens on mhc molecules to t cells. pamp recognition promotes dc maturation, a phenotypic change that empowers them to prime naïve t cells. as a result, an adaptive immune response that specifically targets bacteria-derived antigens is initiated. consequently, any impairment of dc function might contri ...201020158475
novel cooperation experimentally evolved between species.cooperation violates the view of "nature red in tooth and claw" that prevails in our understanding of evolution, yet examples of cooperation abound. most work has focused on maintenance of cooperation within a single species through mechanisms such as kin selection. the factors necessary for the evolutionary origin of aiding unrelated individuals such as members of another species have not been experimentally tested. here, i demonstrate that cooperation between species can be evolved in the labo ...201020100214
characterization of a novel sialic acid transporter of the sodium solute symporter (sss) family and in vivo comparison with known bacterial sialic acid transporters.the function of sialic acids in the biology of bacterial pathogens is reflected by the diverse range of solute transporters that can recognize these sugar acids. here, we use an escherichia colideltanant strain to characterize the function of known and proposed bacterial sialic acid transporters. we discover that the stm1128 gene from salmonella enterica serovar typhimurium, which encodes a member of the sodium solute symporter family, is able to restore growth on sialic acid to the deltanant st ...201020100283
characterization of small cole1-like plasmids conferring kanamycin resistance in salmonella enterica subsp. enterica serovars typhimurium and newport.multi-antibiotic resistant (mr) salmonella enterica serovars typhimurium and newport are an increasing concern in human and animal health. many strains are known to carry antibiotic resistance determinants on multiple plasmids, yet detailed information has been scarce. three plasmids conferring kanamycin (kan) resistance were isolated and nucleotide sequences were determined. two kan(r) plasmids from salmonella newport strains, psn11/00kan and psn02/01kan, were found to be identical and were 569 ...201020100512
both hemolytic anemia and malaria parasite-specific factors increase susceptibility to nontyphoidal salmonella enterica serovar typhimurium infection in mice.severe pediatric malaria is an important risk factor for developing disseminated infections with nontyphoidal salmonella serotypes (nts). while recent animal studies on this subject are lacking, early work suggests that an increased risk for developing systemic nts infection during malaria is caused by hemolytic anemia, which leads to reduced macrophage microbicidal activity. here we established a model for oral salmonella enterica serotype typhimurium challenge in mice infected with plasmodium ...201020100860
recombinant flagellins with partial deletions of the hypervariable domain lose antigenicity but not mucosal adjuvancy.flagellin contains conserved n/c domains for tlr5 binding to activate innate immunity and a middle hypervariable domain harboring the major antigenic epitopes. however, conflict results existed in the previous studies as to whether the hypervariable domain was involved in the cytokine production and adjuvancy of flagellin. here we constructed three flagellin variants (designated as flicdelta190-278, flicdelta220-320, and flicdelta180-400) with deletions in the hypervariable domain. our data demo ...201020102702
ndp52, a novel autophagy receptor for ubiquitin-decorated cytosolic bacteria.autophagy functions as a cell-autonomous effector mechanism of innate immunity by separating bacteria from cytosolic resources and delivering them for lysosomal destruction. how cytosolic bacteria are targeted for autophagy is incompletely understood. we recently discovered that salmonella enterica serotype typhimurium and streptococcus pyogenes are detected by ndp52 (nuclear dot protein 52 kda), after these bacteria enter the cytosol of human cells and become decorated with polyubiquitinated pr ...201020104023
empyema of preexisting subdural hemorrhage caused by a rare salmonella species after exposure to bearded dragons in a foster home.an infant had a subdural empyema caused by the rare salmonella species enterica subspecies houtenae (iv) serotype 44:z4,z23:- after only indirect exposure to exotic reptiles in her foster home. infants recovering from preexisting subdural hematoma are at risk for development of empyema.201020105642
prime-boost immunization using a dna vaccine delivered by attenuated salmonella enterica serovar typhimurium and a killed vaccine completely protects chickens from h5n1 highly pathogenic avian influenza virus.h5n1 highly pathogenic avian influenza virus (hpaiv) has posed a great threat not only for the poultry industry but also for human health. however, an effective vaccine to provide a full spectrum of protection is lacking in the poultry field. in the current study, a novel prime-boost vaccination strategy against h5n1 hpaiv was developed: chickens were first orally immunized with a hemagglutinin (ha) dna vaccine delivered by attenuated salmonella enterica serovar typhimurium, and boosting with a ...201020107004
development of a bead immunoassay to measure vi polysaccharide-specific serum igg after vaccination with the salmonella enterica serovar typhi vi polysaccharide.vi polysaccharide from salmonella enterica serotype typhi is used as one of the available vaccines to prevent typhoid fever. measurement of vi-specific serum antibodies after vaccination with vi polysaccharide by enzyme-linked immunosorbent assay (elisa) may be complicated due to poor binding of the vi polysaccharide to elisa plates resulting in poor reproducibility of measured antibody responses. we chemically conjugated vi polysaccharide to fluorescent beads and performed studies to determine ...201020107010
development and evaluation of a multiplex real-time polymerase chain reaction procedure to clinically type prevalent salmonella enterica serovars.a multiplex real-time polymerase chain reaction procedure was developed to identify the most prevalent clinical isolates of salmonella enterica subsp. enterica. genes from the rfb, flic, fljb, and viab groups that encode the o, h, and vi antigens were used to design 15 primer pairs and taqman probes specific for the genes rfbj, wzx, flic, fljb, wcdb, the sdf-l sequence, and inva, which was used as an internal amplification control. the primers and probes were variously combined into six sets. th ...201020110454
interaction of saccharomyces boulardii with salmonella enterica serovar typhimurium protects mice and modifies t84 cell response to the infection.salmonella pathogenesis engages host cells in two-way biochemical interactions: phagocytosis of bacteria by recruitment of cellular small gtp-binding proteins induced by the bacteria, and by triggering a pro-inflammatory response through activation of mapks and nuclear translocation of nf-kappab. worldwide interest in the use of functional foods containing probiotic bacteria for health promotion and disease prevention has increased significantly. saccharomyces boulardii is a non-pathogenic yeast ...201020111723
comparison of a semi-automated rep-pcr system and multilocus sequence typing for differentiation of salmonella enterica isolates.the accurate sub-typing of salmonella enterica isolates is essential for epidemiological investigations and surveillance of salmonella infections. salmonella isolates are currently identified using the kauffman-white serotyping scheme. multilocus sequence typing (mlst) schemes have been developed for the major bacterial pathogens including salmonella and have assisted in understanding the molecular epidemiology and population biology of these organisms. recently, the diversilab rep-pcr system ha ...201020114063
correlation of the genotoxic activation and kinetic properties of salmonella enterica serovar typhimurium nitroreductases snra and cnr with the redox potentials of nitroaromatic compounds and quinones.bacterial nitroreductases (nrs) catalyse the oxygen-insensitive reduction of several nitro-substituted compounds and quinones. snra and cnr nrs have been previously identified in salmonella enterica serovar typhimurium; they reduce several environmental nitro compounds that display mutagenic activity in the ames test. although some of their biochemical properties have been reported, the substrate specificity of each protein over mutagenic nitro compounds is unknown; even more, the possible relat ...201020118186
flagellated but not hyperfimbriated salmonella enterica serovar typhimurium attaches to and forms biofilms on cholesterol-coated surfaces.the asymptomatic, chronic carrier state of salmonella enterica serovar typhi occurs in the bile-rich gallbladder and is frequently associated with the presence of cholesterol gallstones. we have previously demonstrated that salmonellae form biofilms on human gallstones and cholesterol-coated surfaces in vitro and that bile-induced biofilm formation on cholesterol gallstones promotes gallbladder colonization and maintenance of the carrier state. random transposon mutants of s. enterica serovar ty ...201020118264
role of the c-terminal cytoplasmic domain of flha in bacterial flagellar type iii protein export.for construction of the bacterial flagellum, many of the flagellar proteins are exported into the central channel of the flagellar structure by the flagellar type iii protein export apparatus. flha and flhb, which are integral membrane proteins of the export apparatus, form a docking platform for the soluble components of the export apparatus, flih, flii, and flij. the c-terminal cytoplasmic domain of flha (flha(c)) is required for protein export, but it is not clear how it works. here, we analy ...201020118266
morphologic and cytokine profile characterization of salmonella enterica serovar typhimurium infection in calves with bovine leukocyte adhesion deficiency.the role of neutrophils in the pathogenesis of salmonella enterica typhimurium-induced ruminant and human enteritis and diarrhea has yet to be characterized with in vivo models. to address this question, the in vivo bovine ligated ileal loop model of nontyphoidal salmonellosis was used in calves with the naturally occurring bovine leukocyte adhesion deficiency (blad) mutation whose neutrophils are unable to extravasate and infiltrate the extravascular matrix. data obtained from 4 blad holstein c ...201020118318
salmonella sdia recognizes n-acyl homoserine lactone signals from pectobacterium carotovorum in vitro, but not in a bacterial soft rot.genomes of salmonella enterica isolates, including those linked to outbreaks of produce-associated gastroenteritis, contain sdia, which encodes a receptor of n-acyl homoserine lactones (ahl). ahl are the quorum-sensing signals used by bacteria to coordinately regulate gene expression within -their populations. because s. enterica does not produce its own ahl, sdia is hypothesized to function in the interspecies cross-talk with ahl-producing bacteria. under laboratory conditions, s. enterica resp ...201020121449
bacterial chemoreceptors: providing enhanced features to two-component signaling.bacteria perform chemotaxis utilizing core two-component signaling systems to which have been added enhanced features of signal amplification, sensory adaptation, molecular memory and high sensitivity over a wide dynamic range. chemoreceptors are central to the enhancements. these transmembrane homodimers associate in trimers and in clusters of signaling complexes containing from a few to thousands of receptors. receptor homodimers couple ligand occupancy and adaptational modification to transme ...201020122866
bacterial guanine nucleotide exchange factors sope-like and wxxxe effectors.subversion of rho family small gtpases, which control actin dynamics, is a common infection strategy used by bacterial pathogens. in particular, salmonella enterica serovar typhimurium, shigella flexneri, enteropathogenic escherichia coli (epec), and enterohemorrhagic escherichia coli (ehec) translocate type iii secretion system (t3ss) effector proteins to modulate the rho gtpases rhoa, cdc42, and rac1, which trigger formation of stress fibers, filopodia, and lamellipodia/ruffles, respectively. ...201020123714
enterococcus mundtii st4sa and lactobacillus plantarum 423 alleviated symptoms of salmonella infection, as determined in wistar rats challenged with salmonella enterica serovar typhimurium.wistar rats were administered daily with lactobacillus plantarum 423 and enterococcus mundtii st4sa through intragastric gavage (1 x 10(8) cfu of each strain and a combination of the two strains). sterile saline was used as placebo. after 7 days, the animals were challenged by infection with 2 x 10(8) cfu salmonella enterica serovar typhimurium. after 1 day of treatment with l. plantarum 423 and e. mundtii st4sa, the feed and water intake, and body weight of the rats increased. the faecal moistu ...201020127245
virulotyping and antimicrobial resistance typing of salmonella enterica serovars relevant to human health in europe.the combination of virulence gene and antimicrobial resistance gene typing using dna arrays is a recently developed genomics-based approach to bacterial molecular epidemiology. we have now applied this technology to 523 salmonella enterica subsp. enterica strains collected from various host sources and public health and veterinary institutes across nine european countries. the strain set included the five predominant salmonella serovars isolated in europe (enteritidis, typhimurium, infantis, vir ...201020039795
detection and characterization of extended-spectrum beta-lactamase (tem-52)-producing salmonella serotype infantis from broilers in japan.during 2004 and 2006, multidrug-resistant salmonella enterica subspecies enterica serovar infantis (salmonella infantis) isolates (n = 120) were recovered from broiler cecal samples collected from a meat-processing plant, and the isolates were examined. the study was conducted to detect and characterize extended-spectrum beta-lactamase (esbl)-producing salmonella infantis isolates recovered from broiler chickens and determine the mechanisms of transfer of the resistance traits. extended-spectrum ...201020039796
espm2 is a rhoa guanine nucleotide exchange factor.we investigated how the type iii secretion system wxxxe effectors espm2 of enterohaemorrhagic escherichia coli, which triggers stress fibre formation, and sifa of salmonella enterica serovar typhimurium, which is involved in intracellular survival, modulate rho gtpases. we identified a direct interaction between espm2 or sifa and nucleotide-free rhoa. nuclear magnetic resonance spectroscopy revealed that espm2 has a similar fold to sifa and the guanine nucleotide exchange factor (gef) effector s ...201020039879
successful treatment of refractory septic arthritis caused by salmonella and staphylococcus aureus with preservation of graft function in a long-term renal transplant recipient by total withdrawal of immunosuppressants.an 18-year-old female had received a 2 hla incompatible renal transplant 10 years before. she initially presented with septic arthritis and osteomyelitis caused by salmonella enterica co-infected with staphylococcus aureus of her left knee with development of secondary septic arthritis of the right knee and left shoulder. this was complicated by a recurrent subcutaneous abscess and intermittent high fever. the infection was successfully treated with a combination of a prolonged course of antibio ...201020040356
prevalence and risk factors for salmonella enterica subsp. enterica contamination in french breeding and fattening turkey flocks at the end of the rearing period.an epidemiological study was conducted to estimate the prevalence of salmonella spp. contamination in french commercial breeding and fattening turkey flocks at the end of the rearing period, as part of a european union-wide baseline study. two hundred and five breeding turkey flocks and three hundred and two fattening turkey flocks were included in the study, between october 2006 and september 2007. the salmonella status of flocks was assessed by collecting five environmental faeces samples, ana ...201020044159
structure and mechanisms of a protein-based organelle in escherichia coli.many bacterial cells contain proteinaceous microcompartments that act as simple organelles by sequestering specific metabolic processes involving volatile or toxic metabolites. here we report the three-dimensional (3d) crystal structures, with resolutions between 1.65 and 2.5 angstroms, of the four homologous proteins (euts, eutl, eutk, and eutm) that are thought to be the major shell constituents of a functionally complex ethanolamine utilization (eut) microcompartment. the eut microcompartment ...201020044574
deletion of penicillin-binding protein 5 (pbp5) sensitises escherichia coli cells to beta-lactam agents.escherichia coli penicillin-binding protein 5 (pbp5), a dd-carboxypeptidase encoded by the daca gene, plays a key role in the maintenance of cell shape. although pbp5 shares one of the highest copy numbers among the pbps, it is not essential for cell survival. to determine the effect of this redundant pbp on beta-lactam antibiotic susceptibility, pbp5 was deleted from o-antigen-negative e. coli k-12 (cs109) and o8-antigen-positive e. coli 2443, thus creating strains am15-1 and ag1o5-1, respectiv ...201020047819
changes in the proteome of salmonella enterica serovar thompson as stress adaptation to sublethal concentrations of thymol.thymol is a natural biocide and component of some essential oils from herbs. its inhibitory effect on the growth of different microorganisms is well documented. the precise targets of the antibacterial action of thymol is not yet been fully established, the action seems to take place in different ways. the strain salmonella enterica serovar thompson mcv1 was grown in the presence of a sublethal concentration (0.01%) of thymol. the proteins extracted from treated and untreated cells were subjecte ...201020049861
effect of alpha-cyclodextrin-cinnamic acid inclusion complexes on populations of escherichia coli o157:h7 and salmonella enterica in fruit juices.cinnamic acid (ca), a naturally occurring organic acid found in fruits and spices, has antimicrobial activity against spoilage and pathogenic bacteria, but low aqueous solubility limits its use. the purpose of this study was to determine the effectiveness of solubility-enhancing alpha-cyclodextrin-ca inclusion complexes against escherichia coli o157:h7 and salmonella enterica serovars suspended in apple cider or orange juice at two different incubation temperatures (4 and 26 degrees celsius). tw ...201020051210
immunogenicity of a live recombinant salmonella enterica serovar typhimurium vaccine expressing pspa in neonates and infant mice born from naive and immunized mothers.we are developing a salmonella vectored vaccine to prevent infant pneumonia and other diseases caused by streptococcus pneumoniae. one prerequisite for achieving this goal is to construct and evaluate new recombinant attenuated salmonella vaccine (rasv) strains suitable for use in neonates and infants. salmonella enterica serovar typhimurium strain chi9558(pya4088) specifies delivery of the pneumococcal protective antigen pspa and can protect adult mice from challenge with s. pneumoniae. this st ...201020053873
construction of recombinant attenuated salmonella enterica serovar typhimurium vaccine vector strains for safety in newborn and infant mice.recombinant bacterial vaccines must be safe, efficacious, and well tolerated, especially when administered to newborns and infants to prevent diseases of early childhood. many means of attenuation have been shown to render vaccine strains susceptible to host defenses or unable to colonize lymphoid tissue effectively, thus decreasing their immunogenicity. we have constructed recombinant attenuated salmonella vaccine strains that display high levels of attenuation while retaining the ability to in ...201020053874
effects of exposure to poultry chemical decontaminants on the membrane fluidity of listeria monocytogenes and salmonella enterica strains.there is a lack of work comparing the influence of various poultry chemical decontaminants on the membrane fluidity of pathogenic bacteria. in order to assess the possible role of physical membrane changes on bacterial adaptation to decontaminants, fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene (dph) was measured in listeria monocytogenes and salmonella enterica strains before and after growth in the presence of increasing sub-lethal concentrations of decontaminants (trisodium phosphat ...201020056288
contrasting persistence strategies in salmonella and mycobacterium.long-term survival of persistent bacterial pathogens in mammalian hosts critically depends on their ability to avoid elimination by innate and adaptive immune responses. the persistent human pathogens that cause typhoid fever and tuberculosis exemplify alternative strategies for survival in the host: immune evasion and immune adaptation, respectively. salmonella enterica serotype typhi evades host innate immune responses and inflammation by expressing factors that interfere with its detection as ...201020056478
association between bulk-tank milk salmonella antibody level and high calf mortality in danish dairy herds.salmonella enterica ssp. enterica dublin is the most common salmonella serotype found in the dairy sector in denmark. salmonella antibody level in bulk-tank milk (btm), indicative of salmonella dublin infection in the herd, has been recorded regularly in all danish dairy herds through a surveillance program since 2002. the objective of this study was to investigate whether high btm salmonella antibody level was associated with high calf mortality at herd level. other risk factors for high calf m ...201020059928
a real-time pcr method for the detection of salmonella enterica from food using a target sequence identified by comparative genomic analysis.a 5'-nuclease real-time pcr assay using a minor groove binding probe was developed for the detection of salmonella enterica from artificially contaminated foods. s. enterica-specific sequences were identified by a comparative genomic approach. several species-specific target sequences were evaluated for specificity. a real-time pcr assay was developed targeting a nucleotide sequence within the putative type iii secretion atp synthase gene (ssan). an internal amplification control (iac) probe was ...201020060189
emerging salmonella paratyphi a enteric fever and changing trends in antimicrobial resistance pattern of salmonella in shimla.this retrospective study incorporates a six years, six months (january 2000-june 2006) laboratory data comprising 258 isolates of salmonella. cultures were identified by standard methods. salmonella enterica serotype typhi (s.typhi) was the more frequent serotype isolated i.e., 61.62% with the remaining 38.37% being salmonella enterica serotype paratyphi a (s. paratyphi a). there was emergence of s. paratyphi a as the predominant serotype in 2003-2004 with resurgence of serotype typhi thereon. a ...201020061765
like will to like: abundances of closely related species can predict susceptibility to intestinal colonization by pathogenic and commensal bacteria.the intestinal ecosystem is formed by a complex, yet highly characteristic microbial community. the parameters defining whether this community permits invasion of a new bacterial species are unclear. in particular, inhibition of enteropathogen infection by the gut microbiota ( = colonization resistance) is poorly understood. to analyze the mechanisms of microbiota-mediated protection from salmonella enterica induced enterocolitis, we used a mouse infection model and large scale high-throughput p ...201020062525
the complexities of porin genetic regulation.our understanding of porin regulation has revealed not only increasing complexity in the regulatory mechanisms, but also that the porin repertoire is more extensive than previously conceived. initially, the ompr response regulator was described as the master regulator of porin genes, but many more regulators are involved such as cpxr, phob, lrp, rob, mara, soxs, cadc, crp, fnr, toxr, h-ns, stpa, ihf, hu and leuo. in addition to micf, the first small rna (srna) that was proposed to regulate porin ...201020068355
tracking the dynamic interplay between bacterial and host factors during pathogen-induced vacuole rupture in real time.escape into the host cell cytosol following invasion of mammalian cells is a common strategy used by invasive pathogens. this requires membrane rupture of the vesicular or vacuolar compartment formed around the bacteria after uptake into the host cell. the mechanism of pathogen-induced disassembly of the vacuolar membrane is poorly understood. we established a novel, robust and sensitive fluorescence microscopy method that tracks the precise time point of vacuole rupture upon uptake of gram-nega ...201020070313
molecular typing of salmonella enterica serovar sofia in australia by pulsed-field gel electrophoresis and repetitive element pcr typing.in this study, we used two molecular fingerprinting methods to investigate the genetic and clonal relationship shared by australian salmonella sofia isolates.201020070444
vaccination of mice with salmonella expressing vapa: mucosal and systemic th1 responses provide protection against rhodococcus equi infection.conventional vaccines to prevent the pneumonia caused by rhodococcus equi have not been successful. we have recently demonstrated that immunization with salmonella enterica typhimurium expressing the vapa antigen protects mice against r. equi infection. we now report that oral vaccination of mice with this recombinant strain results in high and persistent fecal levels of antigen-specific iga, and specific proliferation of the spleen cells of immunized mice in response to the in vitro stimulation ...201020072623
glucose and glucose 6-phosphate as carbon sources in extra- and intracellular growth of enteroinvasive escherichia coli and salmonella enterica.to study the role of carbohydrates, in particular glucose, glucose 6-phosphate and mannose, as carbon substrates for extra- and intracellular replication of facultative intracellular enteric bacteria, mutants of two enteroinvasive escherichia coli (eiec) strains and a salmonella enterica serovar typhimurium isolate were constructed that were defective in the uptake of glucose and mannose (deltaptsg, manxyz), glucose 6-phosphate (deltauhpt) or all three carbohydrates (deltaptsg, manxyz, uhpt). th ...201020075042
prevalence and characterization of salmonella gallinarum in the chicken in korea during 2000 to 2008.salmonella enterica serovar gallinarum (salmonella gallinarum) is the causative agent of fowl typhoid (ft), a severe systemic disease of chickens that results in high mortality. since 1992, ft has become one of the most serious bacterial diseases in poultry in korea. the purpose of this study was to investigate the prevalence of ft during 2000 to 2008 and characterize the phenotype and genetic diversity of salmonella gallinarum isolates before and after adopting national-wide vaccination with a ...201020075274
effect of lactic acid bacteria probiotic culture treatment timing on salmonella enteritidis in neonatal broilers.in the present study, a series of experiments were conducted to evaluate the ability of a combination of 3 atcc lactobacilli (lab3) or a commercially available probiotic culture (prob) to reduce salmonella enterica serovar enteritidis (salmonella enteritidis) in broiler chicks. additionally, we varied the timing of prob administration in relationship to salmonella challenge and determined the influence on recovery of enteric salmonella. in experiments 1 to 3, chicks were randomly assigned to tre ...201020075275
exploiting the role of tolc in pathogenicity: identification of a bacteriophage for eradication of salmonella serovars from poultry.using a screening procedure, three bacteriophages, st27, st29, and st35, were identified with selective activity for salmonella enterica serovar typhimurium (sl1344) but not sl1344 tolc::aph. overproduction of tolc led to a lower efficiency of plating (eop), further suggesting that tolc was the target receptor. activity against other serovars of salmonella was observed but not against other species of enterobacteriaceae. this study provides proof of principle that bacteriophages can be active ag ...201020080996
rama, a member of the arac/xyls family, influences both virulence and efflux in salmonella enterica serovar typhimurium.the transcriptomes of salmonella enterica serovar typhimurium sl1344 lacking a functional rama or ramr or with plasmid-mediated high-level overexpression of rama were compared to those of the wild-type parental strain. inactivation of rama led to increased expression of 14 spi-1 genes and decreased expression of three spi-2 genes, and it altered expression of ribosomal biosynthetic genes and several amino acid biosynthetic pathways. furthermore, disruption of rama led to decreased survival withi ...201020081028
interaction of bacillus species and salmonella enterica serovar typhimurium in immune or inflammatory signaling from swine intestinal epithelial cells.previous research evaluated a laboratory strain of bacillus licheniformis (bl) in a model swine epithelium and found it exerted antiinflammatory effects on salmonella enterica serovar typhimurium (sal)-induced secretion of il-8. the current investigation evaluated the antiinflammatory actions of bacillus bacteria available commercially as feed additives for the swine industry. three isolates were obtained from the product, 2 bacillus subtilis (bs1 and bs3) and 1 bl (bl2). swine jejunal epithelia ...201020081082
oral inoculation with salmonella enterica serovar typhimurium or choleraesuis promotes divergent responses in the somatotropic growth axis of swine.enteric disease and immune challenge are processes that have detrimental effects on the growth performance of young swine. the current study tested the hypothesis that salmonella-induced enteric disease would perturb the endocrine growth axis in a serovar-dependent fashion. specifically, we evaluated the effects of salmonella enterica serovar typhimurium (typhimurium) and serovar choleraesuis (choleraesuis) on critical regulatory components of growth in young swine. weaned pigs were housed 2 per ...201020081084
individual and co-operative roles of lactic acid and hydrogen peroxide in the killing activity of enteric strain lactobacillus johnsonii ncc933 and vaginal strain lactobacillus gasseri ks120.1 against enteric, uropathogenic and vaginosis-associated pathogens.the mechanism underlying the killing activity of lactobacillus strains against bacterial pathogens appears to be multifactorial. here, we investigate the respective contributions of hydrogen peroxide and lactic acid in killing bacterial pathogens associated with the human vagina, urinary tract or intestine by two hydrogen peroxide-producing strains. in co-culture, the human intestinal strain lactobacillus johnsonii ncc933 and human vaginal strain lactobacillus gasseri ks120.1 strains killed ente ...201020082639
evaluation of isotope-coded protein labeling (icpl) in the quantitative analysis of complex proteomes.an evaluation of the icpl (isotope-coded protein labeling) non-isobaric labeling technique was performed using two different biological models. two samples containing phage t4 capsids were mixed in a 1:1 ratio after being labeled with the light or heavy versions of the icpl reagent. the analysis of this proteome demonstrated the feasibility of this approach for differential quantitative proteomics and was employed to optimize the experimental parameters of the icpl workflow. icpl-mediated analys ...201020082807
regulation of bacterial conjugation in microaerobiosis by host-encoded functions arcab and sdhabcd.the virulence plasmid of salmonella enterica (pslt) is an f-like conjugative plasmid. high rates of pslt transfer occur in the mammalian gut, a microaerobic environment. in this study, we describe genetic screens for host-encoded activators and repressors of the transfer operon (tra) of pslt. we show that the transcription factor arca is an activator of conjugation, especially under microaerobiosis. in turn, succinate dehydrogenase (sdhabcd) is a repressor of mating in aerobiosis. arca binds ups ...201020083612
duplication frequency in a population of salmonella enterica rapidly approaches steady state with or without recombination.tandem duplications are among the most common mutation events. the high loss rate of duplication suggested that the frequency of duplications in a bacterial population (1/1000) might reflect a steady state dictated by relative rates of formation (k(f)) and loss (k(l)). this possibility was tested for three genetic loci. without homologous recombination (reca), duplication loss rate dropped essentially to zero, but formation rate decreased only slightly and a steady state was still reached rapidl ...201020083614
expression of homing receptors on iga1 and iga2 plasmablasts in blood reflects differential distribution of iga1 and iga2 in various body fluids.although secretory iga is the most abundantly produced ig isotype, the mechanisms underlying the differential distribution of iga subclasses in various body fluids remain unclear. to explore these mechanisms, we examined the distribution of iga subclasses, the influence of the nature and sites of encounters with antigens, and the correlation between iga subclass distribution and homing potentials of circulating iga plasmablasts. iga1 predominated in serum, tears, nasal wash fluid, and saliva; th ...201020089794
characterization of resistance genes in multidrug-resistant salmonella enterica serotype typhimurium isolated from diseased cattle in france (2002 to 2007).we report here the results of the survey of antimicrobial resistance in 148 serotype typhimurium strains isolated from cattle in france from 2002 to 2007 and displaying more than two antimicrobial resistances. salmonella enterica serotype typhimurium of definitive phage type 104 strains that are commonly resistant to ampicillin-amoxicillin, chloramphenicol-florfenicol, streptomycin-spectinomycin, sulfonamides, and tetracycline (acssut phenotype) harbored resistance genes clustered on a complex c ...201020092404
tlr2-, tlr4- and myd88-independent acquired humoral and cellular immunity against salmonella enterica serovar typhimurium.toll-like receptors (tlr) are central to pathogen recognition by the innate immune system. however, their role in the generation of acquired immunity is less clear. using experimental salmonella enterica serovar typhimurium (st) infection of mice, we determined the role of tlr2, tlr4 and of the tlr adaptor protein myeloid differentiation factor 88 (myd88) in the generation of specific t- and b-cell responses against this pathogen. when infected with an attenuated st strain, mice deficient in tlr ...201019895846
salmonella infection of a total knee replacement.salmonella enterica serotype choleraesuis is a rare infective pathogen in total knee arthroplasty and accounts for less than 1% of all cases. in the united kingdom, the most prevalent organisms are staphylococci, which account for over 50% of cases. we present an interesting case report of an infected revision total knee replacement following foreign travel to a region with an increased prevalence of salmonella. the patient presented typically with an effused knee and raised inflammatory markers ...201019897369
short-term signatures of evolutionary change in the salmonella enterica serovar typhimurium 14028 genome.salmonella enterica serovar typhimurium is a gram-negative pathogen that causes gastroenteritis in humans and a typhoid-like disease in mice and is often used as a model for the disease promoted by the human-adapted s. enterica serovar typhi. despite its health importance, the only s. typhimurium strain for which the complete genomic sequence has been determined is the avirulent lt2 strain, which is extensively used in genetic and physiologic studies. here, we report the complete genomic sequenc ...201019897643
bistable expression of csgd in biofilm development of salmonella enterica serovar typhimurium.bacterial persistence in the environment and in the infected host is often aided by the formation of exopolymer-enclosed communities known as biofilms. heterogeneous gene expression takes place in microcompartments formed within the complex biofilm structure. this study describes cell differentiation within an isogenic bacterial cell population based on the example of biofilm formation by salmonella enterica serovar typhimurium. we analyzed the expression of the major biofilm regulator csgd at t ...201019897646
promoter and riboswitch control of the mg2+ transporter mgta from salmonella enterica.the mgta protein from salmonella enterica serovar typhimurium mediates mg(2+) uptake from the periplasm into the cytoplasm. here we report that the phop/phoq two-component regulatory system, which responds to periplasmic mg(2+), governs mgta transcription initiation at all investigated mg(2+) concentrations and that the mg(2+)-sensing 5' leader region of the mgta gene controls transcription elongation into the mgta coding region when salmonella is grown in media with <50 mum mg(2+). overexpressi ...201019897653
the salmonella enterica serotype typhi vi capsular antigen is expressed after the bacterium enters the ileal mucosa.salmonella enterica serotype typhi, the etiological agent of typhoid fever, produces the vi capsular antigen, a virulence factor absent in salmonella enterica serotype typhimurium. previous studies suggest that the capsule-encoding viab locus reduces inflammatory responses in intestinal tissue; however, there are currently no data regarding the in vivo expression of this locus. here we implemented direct and indirect methods to localize and detect vi antigen expression within polarized intestina ...201019901065
transfer of plasmid-mediated ctx-m-9 from salmonella enterica serotype virchow to enterobacteriaceae in human flora-associated rats treated with cefixime.food animals are a potential source of ctx-m resistance genes for humans. we evaluated the transfer of the bla(ctx-m-9) gene from an animal strain of salmonella enterica serotype virchow to enterobacteriaceae of the human intestinal flora by using human flora-associated (hfa) rats with and without cefixime treatment. in the absence of antibiotic, no transconjugant enterobacteria were found in the feces of hfa rats. however, the transfer rate was high if escherichia coli j5 recipient strains were ...201019901088
consumption of fresh fruit juice: how a healthy food practice caused a national outbreak of salmonella panama gastroenteritis.in spring 2008, 15 salmonella panama laboratory-confirmed cases were reported within 2 weeks, twice the average annual number of reported cases of this infrequent serotype in the netherlands. to identify the source responsible for this national outbreak, we carried out an epidemiological, microbiological, and trace-back investigation. in total, 33 cases were reported, and a matched case-control study (23 cases/24 controls) identified consumption of fresh (unpasteurized) fruit juice purchased fro ...201019909088
transcriptome analysis of genes controlled by luxs/autoinducer-2 in salmonella enterica serovar typhimurium.the enteric pathogen salmonella enterica serovar typhimurium uses autoinducer-2 (ai-2) as a signaling molecule. ai-2 requires the luxs gene for its synthesis. the regulation of global gene expression in salmonella typhimurium by luxs/ai-2 is currently not known; therefore, the focus of this study was to elucidate the global gene expression patterns in salmonella typhimurium as regulated by luxs/ai-2. the genes controlled by luxs/ai-2 were identified using microarrays with rna samples from wild-t ...201019909098
real-time reverse-transcriptase--polymerase chain reaction for salmonella enterica detection from jalapeño and serrano peppers.outbreaks of salmonella linked to fresh produce emphasize the need for rapid detection methods to curb the spread of foodborne pathogens. reverse-transcriptase-polymerase chain reaction (rt-pcr) detects the presence of mrna (shorter half-life than dna), with greater potential of detecting viable pathogens. real-time rt-pcr eliminates the need for gel electrophoresis and significantly enhances the speed of detection (<1 day) compared with traditional methods (>5 days). the objectives of this rese ...201019911882
cluster of cases of salmonella enterica serotype rissen infection in a general hospital, italy, 2007.in 2007, three strains of salmonella enterica serotype rissen (s. rissen) were isolated in the laboratory of diagnostic microbiology of the general hospital of prato, tuscany, italy, over a 1 month and half interval of time. the first isolate was recovered on january 26 from an outpatient with enteritis. then, two strains were isolated on february 16 and march 11 respectively, from central venous catheters of patients who were being hospitalized in two departments of the hospital. an epidemiolog ...201019912602
inactivation of escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri on spinach leaves by x-ray.several recent foodborne disease outbreaks associated with leafy green vegetables, including spinach, have been reported. x-ray is a non-thermal technology that has shown promise for reducing pathogenic and spoilage bacteria on spinach leaves. inactivation of inoculated escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri on spinach leaves using x-ray at different doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kgy) was studied. the effect of x-ray on col ...201019913687
effects of x-ray radiation on escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri inoculated on shredded iceberg lettuce.the main goal of this investigation was to study the efficacy of x-ray doses (0.1, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5 and 2.0 kgy) on inoculated escherichia coli o157: h7, listeria monocytogenes, salmonella enterica and shigella flexneri on shredded iceberg lettuce. the second goal was to study the effect of x-ray on the inherent microflora counts and visual color of shredded iceberg lettuce during storage at 4 degrees c for 30 days. treatment with 1.0 kgy x-ray significantly reduced the population o ...201019913700
epidemiological characteristics of salmonella enterica serovar typhimurium from healthy pigs in japan.we characterized 53 salmonella enterica ser. typhimurium strains recovered from healthy pigs during 1998-1999 (n=12) and 2004-2005 (n=41) as to their carriage of dt104 spacer region, class 1 and 2 integrons, virulence genes (spvc, rck, and pefa), and xbai- and blni-pulsed-field gel electrophoresis (pfge) profiles. no dt104 strain was detected in 1998-1999, whereas 65.9% (27/41) of the strains in 2004-2005 were dt104 showing resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, t ...201019915327
development of a dna microarray to detect antimicrobial resistance genes identified in the national center for biotechnology information database.to understand the mechanisms and epidemiology of antimicrobial resistance (ar), the genetic elements responsible must be identified. due to the myriad of possible genes, a high-density genotyping technique is needed for initial screening. to achieve this, ar genes in the national center for biotechnology information genbank database were identified by their annotations and compiled into a nonredundant list of 775 genes. a dna microarray was constructed of 70mer oligonucelotide probes designed to ...201019916789
fitness costs and stability of a high-level ciprofloxacin resistance phenotype in salmonella enterica serotype enteritidis: reduced infectivity associated with decreased expression of salmonella pathogenicity island 1 genes.the fitness costs associated with high-level fluoroquinolone resistance were examined for phenotypically and genotypically characterized ciprofloxacin-resistant salmonella enterica serotype enteritidis mutants (104-cip and 5408-cip; mic, >32 microg/ml). the stability of the fluoroquinolone resistance phenotype in both mutants was investigated to assess whether clones with better fitness could emerge in the absence of antibiotic selective pressure. mutants 104-cip and 5408-cip displayed altered m ...201019917752
novel integron gene cassette arrays identified in a global collection of multi-drug resistant non-typhoidal salmonella enterica.investigation of integron carriage in a global collection of multi-drug resistant salmonella enterica identified 3 unique class 1 integron gene cassette arrays not previously reported in this species. the present study used pcr and dna sequence analysis to characterize the structure of these gene cassette arrays. a approximately 4.0 kb integron containing the gene cassette array arr2/cmla5/bla (oxa10) /aada1 was found in isolates belonging to serovars isangi and typhimurium from south africa. a ...201019921331
the phev phenylalanine trna gene klebsiella pneumoniae clinical isolates is an integration hotspot for possible niche-adaptation genomic islands.horizontally acquired genomic islands may allow bacteria to conquer and colonize previously uncharted niches. four klebsiella pneumoniae trna gene insertion hotspots (arg6, asn34, met56, and phev) in 101 clinical isolates derived from blood, sputum, wound, bile or urine specimens were screened by long-range pcr for the presence or absence of integrated islands. the phev phenylalanine trna gene was the most frequently occupied site and harbored at least three entirely distinct types of islands: ( ...201019921332
adjuvant effects for oral immunization provided by recombinant lactobacillus casei secreting biologically active murine interleukin-1{beta}.vaccine delivery systems using lactic acid bacteria are under development, but their efficiency is insufficient. autologous cytokines, such as interleukin-1beta (il-1beta), are potential adjuvants for mucosal vaccines and can be provided by recombinant lactic acid bacteria. the aim of this study was the construction and evaluation of recombinant lactobacillus casei producing il-1beta as an adjuvant delivery agent. the recombinant strain was constructed using an expression/secretion vector plasmi ...201019923575
salmonella enterica serovar typhimurium mutants completely lacking the f(0)f(1) atpase are novel live attenuated vaccine strains.the f(0)f(1) atpase plays a central role in both the generation of atp and the utilisation of atp for cellular processes such as rotation of bacterial flagella. we have deleted the entire operon encoding the f(0)f(1) atpase, as well as genes encoding individual f(0) or f(1) subunits, in salmonella enteric serovar typhimurium. these mutants were attenuated for virulence, as assessed by bacterial counts in the livers and spleens of intravenously infected mice. the attenuated in vivo growth of the ...201019925904
binding of salmonella-specific antibody facilitates specific t cell responses via augmentation of bacterial uptake and induction of apoptosis in macrophages.most antigens from intracellular bacteria or vaccines induce both humoral and cell-mediated immune responses, but interactions between these responses are not fully understood. this study aims to resolve how specific antibodies participate in the activation of specific t cells in protecting hosts against salmonella enterica serotype typhimurium (s. typhimurium) infection.201019929376
bacteriophage therapy of salmonella enterica: a fresh appraisal of bacteriophage therapy.the most serious criticisms leveled at bacteriophage therapy are as follows: phages induce neutralizing antibodies, phages are active only when administered shortly after bacterial infection, and phage-resistant bacteria emerge rapidly in the course of therapy.201019929381
factors influencing survival of enterotoxigenic escherichia coli, salmonella enterica (serovar typhimurium) and vibrio parahaemolyticus in marine environments.the presence and persistence of enterotoxigenic escherichia coli (etec) is poorly investigated in marine habitats. here we compared etec with the more studied fecal contaminant, salmonella enterica serotype typhimurium (s. enterica) and the marine bacteria vibrio parahaemolyticus. all three species of bacteria were culturable on agar plates during 8 weeks of incubation in seawater. however, the culturability of etec was positively affected by low temperature whereas v. parahaemolyticus was negat ...201019930458
salmonella enterica serovar typhimurium lipopolysaccharide deacylation enhances its intracellular growth within macrophages.modification of lipid a is essential for bacterial adaptation to its host. salmonella typhimurium lpxr potentially detoxifies lipid a by 3'-o-deacylation; however, the involvement of deacylation in its adaptation remains unclear. lpxr-dependent 3'-o-deacylation was observed in the stationary phase. when macrophages were infected with stationary phase bacteria, the intracellular growth of the lpxr-null strain was lower than that of the wild-type strain. furthermore, the expression level of induci ...201019932105
cd8+ t cell adjuvant effects of salmonella flicd flagellin in live vaccine vectors or as purified protein.salmonella flagellin, the flagellum structural subunit, has received particular interest as a vaccine adjuvant conferring enhanced immunogenity to soluble proteins or peptides, both for activation of antibody and cellular immune responses. in the present study, we evaluated the salmonella enterica flicd flagellin as a t cell vaccine adjuvant using as model the 9-mer (syvpsaeqi) synthetic h2(d)-restricted cd8(+) t cell-specific epitope (cs(280-288)) derived from the plasmodium yoelii circumsporoz ...201019932669
conversion of glycerol to poly(3-hydroxypropionate) in recombinant escherichia coli.we have developed the conversion of glycerol into thermoplastic poly(3-hydroxypropionate) [poly(3hp)]. for this, the genes for glycerol dehydratase (dhab1) of clostridium butyricum, propionaldehyde dehydrogenase (pdup) of salmonella enterica serovar typhimurium lt2, and polyhydroxyalkanoate (pha) synthase (phac1) of ralstonia eutropha were expressed in recombinant escherichia coli. poly(3hp) was accumulated up to 11.98% (wt/wt [cell dry weight]) in a two-step, fed-batch fermentation. the present ...201019933347
genome-wide transposon mutagenesis identifies a role for host neuroendocrine stress hormones in regulating the expression of virulence genes in salmonella.bacterial sensing of environmental signals plays a key role in regulating virulence and mediating bacterium-host interactions. the sensing of the neuroendocrine stress hormones epinephrine (adrenaline) and norepinephrine (noradrenaline) plays an important role in modulating bacterial virulence. we used mudj transposon mutagenesis to globally screen for genes regulated by neuroendocrine stress hormones in salmonella enterica serovar typhimurium. we identified eight hormone-regulated genes, includ ...201019933366
bovine muc1 inhibits binding of enteric bacteria to caco-2 cells.inhibition of bacterial adhesion to intestinal epithelial receptors by the consumption of natural food components is an attractive strategy for the prevention of microbial related gastrointestinal illness. we hypothesised that muc1, a highly glycosylated mucin present in cows' milk, may be one such food component. purified bovine muc1 was tested for its ability to inhibit binding of common enteric bacterial pathogens to caco-2 cells grown in vitro. muc1 caused dose-dependent binding inhibition o ...201019936918
in salmonella enterica, 2-methylcitrate blocks gluconeogenesis.strains of salmonella enterica serovar typhimurium lt2 lacking a functional 2-methylcitric acid cycle (2-mcc) display increased sensitivity to propionate. previous work from our group indicated that this sensitivity to propionate is in part due to the production of 2-methylcitrate (2-mc) by the krebs cycle enzyme citrate synthase (glta). here we report in vivo and in vitro data which show that a target of the 2-mc isomer produced by glta (2-mc(glta)) is fructose-1,6-bisphosphatase (fbpase), a ke ...201019948794
identification of the salmonella enterica damx gene product, an inner membrane protein involved in bile resistance.the damx gene product of salmonella enterica serovar typhimurium is a protein located in the inner membrane. damx migrates as a 70-kda protein in sds-page even though the predicted protein size is 46 kda. synthesis of damx protein occurs in both exponential- and stationary-phase cultures. disruption of damx causes severe sensitivity to bile. lack of the outer membrane protein asma suppresses bile sensitivity in salmonella damx mutants.201019948803
synergistic effects of the lactobacillus acidophilus surface layer and nisin on bacterial growth.we have previously described a murein hydrolase activity for the surface layer (s-layer) of lactobacillus acidophilus atcc 4356. here we show that, in combination with nisin, this s-layer acts synergistically to inhibit the growth of pathogenic gram-negative salmonella enterica and potential pathogenic gram-positive bacteria, staphylococcus aureus and bacillus cereus. in addition, bacteriolytic effects were observed for the gram-positive species tested. we postulate that the s-layer enhances the ...201019948852
blacmy-2-positive inca/c plasmids from escherichia coli and salmonella enterica are a distinct component of a larger lineage of plasmids.large multidrug resistance plasmids of the a/c incompatibility complex (inca/c) have been found in a diverse group of gram-negative commensal and pathogenic bacteria. we present three completed sequences from inca/c plasmids that originated from escherichia coli (cattle) and salmonella enterica serovar newport (human) and that carry the cephamycinase gene blacmy-2. these large plasmids (148 to 166 kbp) share extensive sequence identity and synteny. the most divergent plasmid, peh4h, has lost sev ...201019949054
quantitative analysis of the immune response upon salmonella typhimurium infection along the porcine intestinal gut.salmonella enterica serovar typhimurium causes enteric disease and compromises food safety. in pigs, the molecular response of the intestine to s. typhimurium has been traditionally characterized by in vitro models that do not reflect the actual immunological competence of the intestinal mucosa. in this work, we performed an oral s. typhimurium infection study to obtain insight into the in vitro response in three different sections (jejunum, ileum and colon) of the porcine intestine. for this, s ...201019941811
immobilization of bacteriophages on modified silica particles.bacteriophages are selective anti-bacterial agents, which are receiving increasing acceptance by regulatory agencies for use both in the food industry and in clinical settings for biocontrol. while immobilized phage could be particularly useful to create antimicrobial surfaces, current immobilization strategies require chemical bioconjugation to surfaces or more difficult processes involving modification of their head proteins to express specific binding moieties, for example, biotin or cellulos ...201019945158
antimicrobial drug use and antimicrobial resistance in enteric bacteria among cattle from alberta feedlots.the purpose of this study was to determine whether antimicrobial resistance (amr) in foodborne pathogens (escherichia coli o157, salmonella, and campylobacter) and non-type-specific e. coli obtained from fecal samples of feedlot cattle was associated with antimicrobial drug (amd) use. a secondary objective was to determine if amr in non-type-specific e. coli could be used as a predictor of amr in foodborne pathogens. fecal samples were collected from pen floors in 21 alberta feedlots during marc ...201019958100
phosphoribosylpyrophosphate synthetase (prsa) variants alter cellular pools of ribose 5-phosphate and influence thiamine synthesis in salmonella enterica.phosphoribosylamine (pra) is the first intermediate in the common purine/thiamine biosynthetic pathway and is primarily synthesized by the product of the purf gene, glutamine phosphoribosylpyrophosphate (prpp) amidotransferase (e.c. 2.4.2.14). past genetic and biochemical studies have shown that multiple mechanisms for the synthesis of pra independent of purf are present in salmonella enterica. here, we describe mutant alleles of the essential prsa gene, which encodes prpp synthetase (e.c. 2.7.6 ...201019959576
design, expression and characterization of recombinant hybrid peptide attacin-thanatin in escherichia coli.antimicrobial peptides will be attractive and potential candidates as peptide drugs because of their efficient action against microbes and low toxicity to mammal cells. to improve their antibacterial activity, some modifications needs to be made. in this research, the hybrid peptide gene attacin-thanatin with 642 bp in length with preferred codons of e. coli was generated using the technology of gene splicing by overlap extension. the gene was inserted in-frame into e. coli expression plasmid pe ...201019967452
high prevalence of salmonella in tegu lizards (tupinambis merianae), and susceptibility of the serotypes to antibiotics.species of tegu (tupinambis) are the largest lizards in south america. large numbers of these lizards are hunted; there is a vigorous trade in their skins and the meat is consumed by rural and native peoples. the animals are also bred in captivity, an economic activity for rural populations which can help in the animals' conservation. faecal samples from 30 captive-born tegus were analysed for the presence of salmonella in two separate samplings. in the first analysis, samples from 26 animals (8 ...201019968856
validation of double digest selective label database for sequenced prokaryotic genomes.summary: a database for simulation of double digest selective label (ddsl) typing technique has been created and validated against a sequenced strain (salmonella enterica serovar typhimurium strain lt2). in silico bands were in agreement with experimental, and the technique was able to discriminate among strains belonging to the same species. when compared with other strain discrimination techniques, ddsl showed a higher discriminatory power. the database contains precomputed data which may be s ...201019996164
Refresh
firstprev
...51525354555657585960...
nextlast
Displaying items 5701 - 5800 of 11731