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pyrosequencing analysis of the gyrb gene to differentiate bacteria responsible for diarrheal diseases.pathogens causing acute diarrhea include a large variety of species from enterobacteriaceae and vibrionaceae. a method based on pyrosequencing was used here to differentiate bacteria commonly associated with diarrhea in china; the method is targeted to a partial amplicon of the gyrb gene, which encodes the b subunit of dna gyrase. twenty-eight specific polymorphic positions were identified from sequence alignment of a large sequence dataset and targeted using 17 sequencing primers. of 95 isolate ...200818324428
ciprofloxacin-resistant salmonella enterica serotype typhimurium, china.we characterized 44 salmonella enterica serotype typhimurium isolates from tongji hospital outpatients in wuhan, china, may 2002-october 2005. all 31 ciprofloxacin-resistant isolates were also resistant to > or = 8 other antimicrobial drugs and carried > or = 2 mutations in gyra and 1 mutation in parc. class 1 integrons were identified in 37 isolates.200818325271
hypoxia-independent activation of hif-1 by enterobacteriaceae and their siderophores.hypoxia inducible factor-1 (hif-1) is the key transcriptional regulator during adaptation to hypoxia. recent studies provide evidence for hif-1 activation during bacterial infections. however, molecular details of how bacteria activate hif-1 remain unclear. here, we pursued the role of bacterial siderophores in hif-1 activation during infection with enterobacteriaceae.200818325389
chronic enteric salmonella infection in mice leads to severe and persistent intestinal fibrosis.intestinal fibrosis and stricture formation are serious complications of crohn's disease, often requiring surgical intervention. unfortunately, the mechanisms underlying intestinal fibrosis development are poorly understood, in part because of the lack of relevant animal models. here, we present a novel murine model of severe and persistent intestinal fibrosis caused by chronic bacterial-induced colitis.200818325390
epidemiological analysis of salmonella enterica from beef sampled in the slaughterhouse and retailers in dakar (senegal) using pulsed-field gel electrophoresis and antibiotic susceptibility testing.seventy-eight isolates of salmonella spp. isolated from beef sampled from the official city slaughterhouse and from retailers in dakar, senegal were analyzed using serotyping, antimicrobial testing and macrorestriction profiling by pulsed-field gel electrophoresis (pfge). these analyses were done to identify clonal relationships and potential transmission routes in beef channel. xbai macrorestriction allowed defining 17 genotypes among the six main analyzed serotypes: salmonella bredeney (3 geno ...200818325615
salmonella michigan soft tissue infection in an immunocompromised child.a rare case of soft tissue infection due to salmonella michigan in an immunocompromised child is reported. the same organism was isolated from a tortoise kept in the home. immunocompromised patients are especially susceptible to reptile-associated salmonellosis and should be advised appropriately.200818326014
optimization and validation of a simple method using p22::luxab bacteriophage for rapid detection of salmonella enterica serotypes a, b, and d in poultry samples.a simple method was developed for the fast and inexpensive detection of salmonella typhimurium using a recombinant p22::luxab phage. all the steps from phage production to detection were considered. a strain of salmonella typhimurium harboring the prophage p22::luxab was grown in batch culture to produce spontaneously the recombinant bacteriophage. batch production to stationary phase was better for propagation of the phage and led to a total population of 4.3 x 10(9) (+/-4.3 x 10(9)) pfu/ml of ...200818326191
migration of salmonella enteritidis phage type 30 through almond hulls and shells.the ability of salmonella to migrate from an external aqueous environment through the almond hull and shell, and to colonize the kernel, was evaluated in two ways. first, the outer surface of shell halves from five varieties of almonds that differed in shell hardness were placed in contact with a suspension of salmonella enterica serovar enteritidis phage type 30 for 24 h at 24 degrees c. salmonella enteritidis was isolated from the inside of these almond shells in 46 and 100% of the samples, by ...200818326194
class 1 integrons and salmonella genomic island 1 among salmonella enterica isolated from poultry and swine.two hundred eleven salmonella enterica strains representing 35 serotypes isolated from healthy poultry (n=103) and swine (n=108) were used in this study. the occurrence and characteristics of class 1 integrons were investigated. salmonella genomic islands (sgis) and the horizontal transfer of integrons were assessed. one hundred eighty-six isolates (88%) were resistant to at least one antimicrobial and 140 isolates (66%) were multidrug resistant. the inti1 gene was present in 54 isolates (25.6%) ...200818328001
crystal structure of yihs in complex with d-mannose: structural annotation of escherichia coli and salmonella enterica yihs-encoded proteins to an aldose-ketose isomerase.the three-dimensional structure of a salmonella enterica hypothetical protein yihs is significantly similar to that of n-acyl-d-glucosamine 2-epimerase (age) with respect to a common scaffold, an alpha6/alpha6-barrel, although the function of yihs remains to be clarified. to identify the function of yihs, escherichia coli and s. enterica yihs proteins were overexpressed in e. coli, purified, and characterized. both proteins were found to show no age activity but showed cofactor-independent aldos ...200818328504
cross-protective immunity conferred by a dna adenine methylase deficient salmonella enterica serovar typhimurium vaccine in calves challenged with salmonella serovar newport.intensive livestock production and management systems are associated with increased fecal-oral pathogen transmission and a resultant high prevalence of multiple salmonella serovars in many large dairy farms and feedlots. thus, it is imperative to develop livestock vaccines that are capable of eliciting potent states of cross-protective immunity against a diversity of serovars of a given species. immunization with modified live salmonella enterica serovar typhimurium vaccine strains, that lack th ...200818329764
low-level resistance to ciprofloxacin in non-typhi salmonella enterica isolated from human gastroenteritis in dakar, senegal (2004--2006). 200818329856
rose represses std fimbrial expression in salmonella enterica serotype typhimurium.the salmonella enterica serotype typhimurium (s. typhimurium) genome contains a large repertoire of putative fimbrial operons that remain poorly characterized because they are not expressed in vitro. in this study, insertions that induced expression of the putative stdabcd fimbrial operon were identified from a random bank of transposon mutants by screening with immuno-magnetic particles for ligand expression (simple). transposon insertions upstream of csgc and lrha or within dam, setb and stm44 ...200818331470
nationwide surveillance of salmonella in the faeces of pigs in japan.the prevalence of faecal carriage of salmonella in 5393 pigs reared on 218 pig farms located in 31 of 47 prefectures in japan over the period july 2003 to june 2005 was investigated. we isolated 172 strains belonging to 20 serovars and one untypable salmonella enterica from 169 pig faecal samples (3.1%) collected from 48 farms (22.0%). the most prevalent type of s. enterica was untypable o4,12:d:- which lacks phase 2 flagellar antigen, representing 29.1% (50/172) of all isolates. of 26 s. enteri ...200818331516
intravaginal immunization of mice with recombinant salmonella enterica serovar typhimurium expressing human papillomavirus type 16 antigens as a potential route of vaccination against cervical cancer.cervical cancer, the second leading cause of cancer deaths in women, is the consequence of high-risk human papillomavirus (hpv) infections. toward the development of therapeutic vaccines that can induce both innate and adaptive mucosal immune responses, we analyzed intravaginal (ivag) vaccine delivery of live attenuated salmonella enterica serovar typhimurium expressing hpv16l1 as a model antigen. innate immune responses were examined in cervicovaginal tissues by determining gene expression patt ...200818332214
complete nucleotide sequence of a virulence plasmid of salmonella enterica serovar dublin and its phylogenetic relationship to the virulence plasmids of serovars choleraesuis, enteritidis and typhimurium.the complete nucleotide sequence of pou1113 (psdvu), one of the two types of virulence plasmids of salmonella enterica serovar dublin, was determined. it contained 80 156 bp with 53.8 mol% g+c content. approximately 70 genes could be discerned. compared with pstv, the virulence plasmid of serovar typhimurium, pou1113 was shorter owing to a missing region amounting to c. 10 kb; furthermore, except for a unique 10 849-bp region, the nucleotide as well as deduced amino acid sequences of pou1113 wer ...200818336553
recombinant attenuated salmonella enterica serovar typhimurium expressing the carboxy-terminal domain of alpha toxin from clostridium perfringens induces protective responses against necrotic enteritis in chickens.clostridium perfringens-induced necrotic enteritis (ne) is a widespread disease in chickens that causes high mortality and reduced growth performance. traditionally, ne was controlled by the routine application of antimicrobials in the feed, a practice that currently is unpopular. consequently, there has been an increase in the occurrence of ne, and it has become a threat to the current objective of antimicrobial-free farming. the pathogenesis of ne is associated with the proliferation of c. per ...200818337376
synergistic antitumoral effects of human telomerase reverse transcriptase-mediated dual-apoptosis-related gene vector delivered by orally attenuated salmonella enterica serovar typhimurium in murine tumor models.salmonella enterica serovar typhimurium (s. typhimurium), a facultative anaerobe, has been reported to be capable of both selectively amplifying and expressing exogenous genes within tumors. in addition, previous studies have demonstrated that the human telomerase reverse transcriptase (htert) promoter could confine gene expression strictly to the telomerase-positive cancer cells. in the present study, we used attenuated s. typhimurium as a carrier to deliver a eukaryotic expression vector (psnh ...200818338832
comparison of antimicrobial activity in the epidermal mucus extracts of fish.the mucus layer on the surface of fish consists of several antimicrobial agents that provide a first line of defense against invading pathogens. to date, little is known about the antimicrobial properties of the mucus of arctic char (salvelinus alpinus), brook trout (s. fontinalis), koi carp (cyprinus carpio sub sp. koi), striped bass (morone saxatilis), haddock (melanogrammus aeglefinus) and hagfish (myxine glutinosa). the epidermal mucus samples from these fish were extracted with acidic, orga ...200818342561
detection of salmonella enterica in food using two-step enrichment and real-time polymerase chain reaction.a new real-time polymerase chain reaction-based method was developed for the detection of salmonella enterica in food.200818346136
t cells help to amplify inflammatory responses induced by salmonella enterica serotype typhimurium in the intestinal mucosa.salmonella enterica serotype typhimurium causes an acute inflammatory reaction in the ceca of streptomycin-pretreated mice. we determined global changes in gene expression elicited by serotype typhimurium in the cecal mucosa. the gene expression profile was dominated by t-cell-derived cytokines and genes whose expression is known to be induced by these cytokines. markedly increased mrna levels of genes encoding gamma interferon (ifn-gamma), interleukin-22 (il-22), and il-17 were detected by quan ...200818347048
toll-like receptor 4 mediates an antitumor host response induced by salmonella choleraesuis.we have shown tumor-targeting and antitumor activities of an attenuated salmonella choleraesuis in various tumor models. meanwhile, host factors, including innate and adaptive immune responses, play roles in salmonella-induced antitumor activity. toll-like receptor 4 (tlr4) is identified as a signaling receptor for lipopolysaccharide derived from gram-negative bacteria. however, the detailed mechanism of the s. choleraesuis-induced antitumor immune response via tlr4 remained uncertain.200818347194
distribution of salmonella pathogenicity island (spi)-8 and spi-10 among different serotypes of salmonella.many virulence phenotypes of salmonella enterica are encoded by genes located on pathogenicity islands. based on genome analysis, it is predicted that salmonella pathogenicity island (spi)-8 is restricted to salmonella serovars typhi and paratyphi a, and spi-10 to salmonella serovars typhi, paratyphi, enteritidis, dublin and gallinarum. this study was conducted to investigate the distribution of spi-8 and spi-10 among salmonella isolates from sprouts, fish, water and blood. a total of 110 salmon ...200818349359
nitric oxide antagonizes the acid tolerance response that protects salmonella against innate gastric defenses.reactive nitrogen species (rns) derived from dietary and salivary inorganic nitrogen oxides foment innate host defenses associated with the acidity of the stomach. the mechanisms by which these reactive species exert antimicrobial activity in the gastric lumen are, however, poorly understood.200818350168
salmonella secreted factor l deubiquitinase of salmonella typhimurium inhibits nf-kappab, suppresses ikappabalpha ubiquitination and modulates innate immune responses.salmonella enterica translocates virulent factors into host cells using type iii secretion systems to promote host colonization, intracellular bacterial replication and survival, and disease pathogenesis. among many effectors, the type iii secretion system encoded in salmonella pathogenicity island 2 translocates a salmonella-specific protein, designated salmonella secreted factor l (ssel), a putative virulence factor possessing deubiquitinase activity. in this study, we attempt to elucidate the ...200818354230
cloning, expression and purification of a glycosylated form of the dna-binding protein dps from salmonella enterica typhimurium.dps, found in many eubacterial and archaebacterial species, appears to protect cells from oxidative stress and/or nutrient-limited environment. dps has been shown to accumulate during the stationary phase, to bind to dna non-specifically, and to form a crystalline structure that compacts and protects the chromosome. our previous results have indicated that dps is glycosylated at least for a certain period of the bacterial cell physiology and this glycosylation is thought to be orchestrated by so ...200818358740
first report of ctx-m-15 in salmonella enterica serotype kedougou recovered from an algerian hospital. 200818360298
molecular epidemiological analysis and microbial source tracking of salmonella enterica serovars in a preharvest turkey production environment.epidemiological studies were conducted to source track and delineate horizontal transmission pathways of salmonella serovars in a turkey production environment. salmonella enterica serovar heidelberg (n = 111), salmonella senftenberg (n = 14), salmonella muenster (n = 10), unidentifiable "roughs" (n = 5), salmonella anatum (n = 3), and salmonella worthington (n = 2) were isolated from the birds' cecal and crop contents, litter, environmental swabs, drinkers, and feed samples. these strains (n = ...200818361686
induction of guanylate binding protein 5 by gamma interferon increases susceptibility to salmonella enterica serovar typhimurium-induced pyroptosis in raw 264.7 cells.the regulation of caspase-1 activation in macrophages plays a central role in host defense against bacterial pathogens. the activation of caspase-1 by the detection of bacterial products through nod-like receptors leads to the secretion of mature interleukin-1beta (il-1beta) and il-18 and the induction of rapid host cell death (pyroptosis). here, we report that pyroptosis induced by salmonella enterica serovar typhimurium can be positively regulated by prior gamma interferon (ifn-gamma) stimulat ...200818362138
regulatory and structural differences in the cu,zn-superoxide dismutases of salmonella enterica and their significance for virulence.many of the most virulent strains of salmonella enterica produce two distinct cu,zn-superoxide dismutases (sodci and sodcii). the bacteriophage-encoded sodci enzyme makes the greater contribution to salmonella virulence. we have performed a detailed comparison of the functional, structural, and regulatory properties of the salmonella sodc enzymes. here we demonstrate that sodci and sodcii differ with regard to specific activity, protease resistance, metal affinity, and peroxidative activity, wit ...200818362154
salmonella enterica serotype typhimurium infection causing mortality in eurasian tree sparrows (passer montanus) in hokkaido. 200818362416
synthesis and biological activity of analogues of vanchrobactin, a siderophore from vibrio anguillarum serotype o2.several analogues of vanchrobactin, a catechol siderophore isolated from the bacterial fish pathogen vibrio anguillarum serotype o2 strain rv22, have been synthesized. the biological evaluation of these novel compounds showed that most of them are active as siderophores, as determined by growth promotion assays using the producer strain, as well as v. anguillarum serotype o1, salmonella enterica, and erwinia chrysanthemi. these compounds also gave a positive chrome azurol-s (cas) test. on the ba ...200818362969
modelling within-host spatiotemporal dynamics of invasive bacterial disease.mechanistic determinants of bacterial growth, death, and spread within mammalian hosts cannot be fully resolved studying a single bacterial population. they are also currently poorly understood. here, we report on the application of sophisticated experimental approaches to map spatiotemporal population dynamics of bacteria during an infection. we analyzed heterogeneous traits of simultaneous infections with tagged salmonella enterica populations (wild-type isogenic tagged strains [wits]) in wild ...200818399718
interactions of some common pathogenic bacteria with acanthamoeba polyphaga.protozoan grazing is a major trophic pathway whereby the biomass re-enters the food web. nonetheless, not all bacteria are digested by protozoa and the number known to evade digestion, resulting in their environmental augmentation, is increasing. we investigated the interactions of bacillus cereus, enterococcus faecalis, enteropathogenic escherichia coli (epec), listeria monocytogenes, salmonella enterica serovar typhimurium, and methicillin-sensitive staphylococcus aureus (mssa), with the amoeb ...200818399997
optimization of vi capsular polysaccharide production during growth of salmonella enterica serotype typhi ty2 in a bioreactor.vi capsular polysaccharide is synthesized during growth of salmonella typhi ty2 and is spontaneously released from the bacterial cells into the culture medium during culture. vi production was dependent on cell growth and the greater the cell mass the greater the production of vi. using fed batch culture to optimize bacterial growth resulted is an increase in cell mass and consequently vi production. the yield of vi obtained in fed batch culture was 415 mgl(-1), which was over three times that, ...200818400326
competition of lactobacillus paracasei with salmonella enterica for adhesion to caco-2 cells.competition of commensal and probiotic bacteria with pathogens for adhesion and colonization is one of the important protective mechanisms of gastrointestinal tract. in this study, we examined the ability of lactobacillus paracasei to inhibit the adhesion of pathogenic salmonella enterica to human colon adenocarcinoma caco-2 cells. caco-2 cells were grown for 6 or 21 days to obtain nondifferentiated or well-differentiated cells, respectively. in adhesion experiments, bacteria were added to the c ...200818401442
impact of dietary components on chicken immune system and salmonella infection.salmonella enterica serovars are facultative intracellular pathogens that may cause serious illness in poultry and humans. human infection by two common serovars, salmonella enteritidis (se) and salmonella typhimurium (st) usually occurs via food-borne transmission. consumption of raw or undercooked contaminated eggs usually causes se infection, while st is transmitted by contaminated chicken meat. there are several reports on dietary interventions, including fatty acid modifications, probiotic ...200818251669
evaluation of commercial antisera for salmonella serotyping.we compared a set of commercial salmonella somatic and flagellar serotyping antisera to in-house-prepared antisera from the microbial diseases laboratory, california department of public health, using 327 salmonella enterica strains belonging to subgroups i, ii, iiia, iiib, and iv. the sensitivities of denka seiken (tokyo, japan) somatic and flagellar antisera (using a tube agglutination assay) were 94.0% and 99.2%, respectively, and the specificity was 100% for both sets of sera. polyvalent o a ...200818094130
nalidixic acid-resistant salmonella enterica serotype typhi infection presenting with sub-intestinal obstruction and mesenteric adenitis.nalidixic acid-resistant salmonella typhi narst infections increase minimal inhibitory concentrations of fluoroquinolones, due to chromosomal mutations in the gene encoding dna gyrase, and can lead to a delayed treatment response. this in turn alters the course of the disease allowing for a protracted period of illness and the occurrence of complications. in this case report, we present a patient from the indian sub-continent, who was diagnosed with narst complicated by sub-intestinal obstructio ...200818176688
genetic detoxification of an aroa salmonella enterica serovar typhimurium vaccine strain does not compromise protection against virulent salmonella and enhances the immune responses towards a protective malarial antigen.live salmonella vaccines are limited in use by the inherent toxicity of the lipopolysaccharide. the waan gene encodes a myristyl transferase required for the secondary acylation of lipid a in lipopolysaccharide. a waan mutant exhibits reduced induction of the inflammatory cytokines associated with lipopolysaccharide toxicity. here the characteristics of a salmonella enterica serovar typhimurium aroa waan mutant (sk100) in vitro and in vivo compared with its parent aroa strain (sl3261) were descr ...200818177343
use of episcopic differential interference contrast microscopy to identify bacterial biofilms on salad leaves and track colonization by salmonella thompson.zoonotic pathogens such as salmonella can cause gastrointestinal illness if they are ingested with food. foods such as salads pose a greater risk because they are consumed raw and have been the source of major outbreaks of disease from fresh produce. the novel light microscopy methods used in this study allow detailed, high resolution imaging of the leaf surface environment (the phyllosphere) and allow pathogen tracking. episcopic differential interference contrast microscopy coupled with epiflu ...200818177375
conjugal transfer of the salmonella enterica virulence plasmid in the mouse intestine.balb/c mice were infected with two salmonella enterica serovar typhimurium strains, one of which lacked the virulence plasmid. transconjugants were found at high frequencies in the mouse feces and at low frequencies in the liver and the spleen, suggesting that mating occurred in the gut. laboratory conditions that mimic those of the small intestine (microaerophilic growth in the presence of 0.3 m nacl) increased the frequency of virulence plasmid transfer. sodium deoxycholate, which is found at ...200818178735
epa worst case water microcosms for testing phage biocontrol of salmonella.a microplate method was developed as a tool to test phages for their ability to control salmonella in aqueous environments. the method used epa (u.s. environmental protection agency) worst case water (wcw) in 96-well plates. the wcw provided a consistent and relatively simple defined turbid aqueous matrix, high in total organic carbon (toc) and total dissolved salts (tds), to simulate swine lagoon effluent, without the inconvenience of malodor and confounding effects from other biological factor ...200818178900
characterization of multiple-antimicrobial-resistant salmonella enterica subsp. enterica isolated from indigenous vegetables and poultry in malaysia.the aims of this communication were to study characterization of serogroups among salmonella isolates and the relationship of antimicrobial resistance to serogroups. multiple antimicrobial resistance (mar) was performed on 189 salmonella enterica isolates associated with 38 different serovars that were recovered from poultry and four types of indigenous vegetables.200818179445
induction of the carrier state in pigeons infected with salmonella enterica subspecies enterica serovar typhimurium pt99 by treatment with florfenicol: a matter of pharmacokinetics.paratyphoid caused by salmonella enterica subsp. enterica serovar typhimurium is the main bacterial disease in pigeons. the ability of salmonella serovar typhimurium to persist intracellularly inside pigeon macrophages results in the development of chronic carriers, which maintain the infection in the flock. in this study, the effect of drinking-water medication with florfenicol on salmonella infection in pigeons was examined. the pharmacokinetics of florfenicol in pigeons revealed a relatively ...200818180355
antimicrobial drug resistance in human nontyphoidal salmonella isolates in europe 2000-2004: a report from the enter-net international surveillance network.a 5-year survey, from 2000 to 2004, of results of antimicrobial susceptibility testing for 11 antimicrobials for 134,310 isolates of nontyphoidal salmonellas from cases of human infection in 10 european countries has demonstrated an overall increase in the occurrence of resistance, from 57% to 66% over the period of study. in contrast, multiple resistance (to four or more antimicrobial drugs) has declined from 18% to 15%. the most significant increase in resistance has been to nalidixic acid (14 ...200818366323
slc41a1 is a novel mammalian mg2+ carrier.the molecular biology of mammalian magnesium transporters and their interrelations in cellular magnesium homeostasis are largely unknown. recently, the mouse slc41a1 protein was suggested to be a candidate magnesium transporter with channel-like properties when overexpressed in xenopus laevis oocytes. here, we demonstrate that human slc41a1 overexpressed in hek293 cells forms protein complexes and locates to the plasma membrane without, however, giving rise to any detectable magnesium currents d ...200818367447
pcr method to identify salmonella enterica serovars typhi, paratyphi a, and paratyphi b among salmonella isolates from the blood of patients with clinical enteric fever.pcr methodology was developed to identify salmonella enterica serovars typhi, paratyphi a, and paratyphi b. one multiplex pcr identifies serogroup d, a, and b and vi-positive strains; another confirms flagellar antigen "d," "a," or "b." blinded testing of 664 malian and chilean salmonella blood isolates demonstrated 100% sensitivity and specificity.200818367574
salicylic acid-based poly(anhydride esters) for control of biofilm formation in salmonella enterica serovar typhimurium.bacterial biofilms generally are more resistant to stresses as compared with free planktonic cells. therefore, the discovery of antimicrobial stress factors that have strong inhibitory effects on bacterial biofilm formation would have great impact on the food, personal care, and medical industries.200818373656
investigating the function of rho family gtpases during salmonella/host cell interactions.salmonella enterica comprise a family of pathogenic gram-negative bacteria that have evolved sophisticated virulence mechanisms to enter non-phagocytic cells. the entry event is the result of a carefully orchestrated modulation of rho family gtpase activity within the host cell, which in turn triggers localized remodeling of the actin cytoskeleton. these cytoskeletal rearrangements drive profuse membrane ruffling and lamellipodial extensions that envelop bacteria and trigger their internalizatio ...200818374162
do salmonella carry spare tyres?salmonellae are enterobacteria that have the unique ability to change their flagellar composition by switching expression among two loci that encode the major flagellin protein. this property is not available to all salmonella, but is species, subspecies and serotype specific. curiously, the subsequent loss of the second locus in some lineages of salmonella has apparently been tolerated and, indeed, has led to considerable success for some lineages. we discuss here an evolutionary model for main ...200818375124
transferable, multiple antibiotic and mercury resistance in atlantic canadian isolates of aeromonas salmonicida subsp. salmonicida is associated with carriage of an inca/c plasmid similar to the salmonella enterica plasmid psn254.the aim of this study was to examine the molecular basis for multiple antibiotic and mercury resistance in canadian isolates of aeromonas salmonicida subsp. salmonicida.200818375380
a combination of cytochrome c nitrite reductase (nrfa) and flavorubredoxin (norv) protects salmonella enterica serovar typhimurium against killing by no in anoxic environments.the enteric bacterium salmonella enterica serovar typhimurium is a pathogen that is highly adapted for both intracellular and extracellular survival in a range of oxic and anoxic environments. the cytotoxic radical nitric oxide (no) is encountered in many of these environments. protection against no may involve reductive detoxification in low-oxygen environments, and three enzymes, flavorubredoxin (norv), flavohaemoglobin (hmpa) and cytochrome c nitrite reductase (nrfa), have been shown to reduc ...200818375814
antimicrobial resistance of salmonella enterica isolates from apparently healthy and clinically ill finishing pigs in spain.this study was the first conducted in spain to evaluate the occurrence of antimicrobial resistance and multi-resistance in salmonella isolates recovered from finishing pigs from spanish swine farms distributed over the whole country. for this purpose, 290 salmonella isolates recovered from apparently healthy finishing pigs in a farm-based cross-sectional study and 192 salmonella isolates recovered from faecal samples of finishing pigs suffering from diarrhoea were investigated. resistance to a p ...200818387141
longitudinal study of salmonella infection in italian farrow-to-finish swine herds.a longitudinal study of salmonella enterica infection was carried out in five italian farrow-to-finish swine herds previously known to be infected by salmonella. five litters were randomly selected from each herd and in each litter six piglets were randomly selected and individually identified. thus, the study included 30 pigs from each farm. at weaning, individual blood samples were collected for serological examination from all selected piglets and on the same day from all sows in the farrowin ...200818387144
a comparison of sugar indicators enables a universal high-throughput sugar-1-phosphate nucleotidyltransferase assay.a systematic comparison of six sugar indicators for their sensitivity, specificity, cross-reactivity, and suitability in the context of crude lysates revealed para-hydroxybenzoic acid hydrazide (phbh) to be best suited for application in a plate-based phosphatase-assisted universal sugar-1-phosphate nucleotidyltransferase assay. the addition of a general phosphatase to nucleotidyltransferase reaction aliquots enabled the conversion of remaining sugar-1-phosphate to free sugar, the concentration ...200818387352
structural investigations into the interaction of hemoglobin and part structures with bacterial endotoxins.an understanding of details of the interaction mechanisms of bacterial endotoxins (lipopolysaccharide, lps) with the oxygen transport protein hemoglobin is still lacking, despite its high biological relevance. here, a biophysical investigation into the endotoxin:hemoglobin interaction is presented which comprises the use of various rough mutant lps as well as free lipid a; in addition to the complete hemoglobin molecule from fetal sheep extract, also the partial structure alpha-chain and the hem ...200818387918
proteomic analysis of triclosan resistance in salmonella enterica serovar typhimurium.the aim of this study was to determine and compare the proteomes of three triclosan-resistant mutants of salmonella enterica serovar typhimurium in order to identify proteins involved in triclosan resistance.200818388111
triclosan resistance in salmonella enterica serovar typhimurium.the aim of this study was to characterize the mechanisms of resistance to triclosan in salmonella enterica serovar typhimurium.200818388112
a novel secretion pathway of salmonella enterica acts as an antivirulence modulator during salmonellosis.salmonella spp. are gram-negative enteropathogenic bacteria that infect a variety of vertebrate hosts. like any other living organism, protein secretion is a fundamental process essential for various aspects of salmonella biology. herein we report the identification and characterization of a horizontally acquired, autonomous and previously unreported secretion pathway. in salmonella enterica serovar typhimurium, this novel secretion pathway is encoded by stm1669 and stm1668, designated zirt and ...200818389060
an antibody microarray, in multiwell plate format, for multiplex screening of foodborne pathogenic bacteria and biomolecules.intoxication and infection caused by foodborne pathogens are important problems worldwide, and screening tests for multiple pathogens are needed because foods may be contaminated with multiple pathogens and/or toxic metabolites. we developed a 96-well microplate, multiplex antibody microarray method to simultaneously capture and detect escherichia coli o157:h7 and salmonella enterica serovar typhimurium (s. typhimurium), as well as a biomolecule (chicken immunoglobulin g or igg employed as a pro ...200818389224
insertion hot spot for horizontally acquired dna within a bidirectional small-rna locus in salmonella enterica.in escherichia coli and salmonella enterica, ryea and ryeb rnas are encoded on opposite dna strands at the same locus. we present evidence indicating that the last 23 bp of the ryeb gene, corresponding to an internal portion of the ryea gene, served repeatedly as the integration site for exogenous dna during salmonella evolution and still act as an attachment site for present-day bacteriophages. interestingly, ryea sequence and expression are modified upon lysogenization.200818390661
mobilization of the incq plasmid r300b with a chromosomal conjugation system in salmonella enterica serovar typhi.salmonella pathogenicity island 7 (spi-7) in salmonella enterica serovar typhi appears to be related to other genomic islands. evidence suggests that spi-7 is susceptible to spontaneous circularization, loss, and transposition. here, we demonstrate that a region within spi-7 has the ability to mobilize the small incq plasmid r300b.200818390666
down-modulation of tcr expression by salmonella enterica serovar typhimurium.t cell-mediated adaptive immunity is required to help clear infection with the facultative intracellular bacterial pathogen salmonella enterica serovar typhimurium (s. typhimurium), yet development of t cell-mediated adaptive immunity to s. typhimurium has been described as slow and inefficient. a key step in inducing t cell-mediated adaptive immunity is t cell priming; the activation, proliferation, and differentiation of naive t cells following initial encounter with ag. we previously demonstr ...200818390741
the innate immune response to salmonella enterica serovar typhimurium by macrophages is dependent on trem2-dap12.macrophage recognition of salmonella enterica serovar typhimurium leads to a cascade of signaling events, including the activation of src family and syk kinases and the production of reactive oxygen species (ros), which are critical for host innate defense during early stages of bacterial infection. ros production depends on the nadph oxidase, but little is known about the innate immune receptors and proximal adapters that regulate salmonella-induced ros. herein, we demonstrate that serovar typh ...200818391000
toll-like receptor gene expression in cecum and spleen of advanced intercross line chicks infected with salmonella enterica serovar enteritidis.understanding the changes in host gene expression that occur with bacterial infection will help to elucidate the basis of molecular genetic control of disease resistance. the effect of infecting chicks with salmonella enterica serovar enteritidis on the rna expression level of toll-like receptor (tlr) genes, and the correlation between tlr rna expression level and bacterial burden in the cecum and spleen of young birds was studied. chicks from two advanced intercross lines were either infected o ...200818394716
ultrafiltration-based techniques for rapid and simultaneous concentration of multiple microbe classes from 100-l tap water samples.this study focused on ultrafiltration as a technique for simultaneously concentrating and recovering viruses, bacteria and parasites in 100-l drinking water samples. a chemical dispersant, sodium polyphosphate, and tween 80 were used to increase microbial recovery efficiencies. secondary concentration was performed to reduce sample volumes to 3-5 ml for analysis using tissue culture, microscopy, and real-time pcr and rt-pcr. at seeding levels of 100-1000 (cfu, pfu, oocysts, or particles), a "hig ...200818395278
human-derived probiotic lactobacillus reuteri demonstrate antimicrobial activities targeting diverse enteric bacterial pathogens.lactobacillus reuteri is a commensal-derived anaerobic probiotic that resides in the human gastrointestinal tract. l. reuteri converts glycerol into a potent broad-spectrum antimicrobial compound, reuterin, which inhibits the growth of gram-positive and gram-negative bacteria. in this study, we compared four human-derived l. reuteri isolates (atcc 55730, atcc pta 6475, atcc pta 4659 and atcc pta 5289) in their ability to produce reuterin and to inhibit the growth of different enteric pathogens i ...200818396068
defective t-cell function leading to reduced antibody production in a kleisin-beta mutant mouse.the recently described nessy (ncaph2nes/nes) mutant mouse strain has a defect in t-cell development caused by a mutation in the ubiquitous kleisin-beta (also known as ncaph2). kleisin-beta is a subunit of the condensin ii complex involved in chromosome condensation during mitosis. the nessy phenotype is characterized by cd44hi cd8+ peripheral t cells, 10-20% of normal thymocyte numbers and 2.5-fold fewer alphabeta t cells in the spleen compared with wild-type mice. in this study we examined the ...200818397266
nramp1 expression by dendritic cells modulates inflammatory responses during salmonella typhimurium infection.host resistance against salmonella enterica serovar typhimurium (s. typhimurium) is mediated by natural resistance-associated macrophage protein 1 (nramp1/slc11a1). nramp1 is critical to host defence, as mice lacking nramp1 fail to control bacterial replication and succumb to low doses of s. typhimurium. despite this crucial role, the mechanisms underlying nramp1's protective effects are unclear. dendritic cells (dcs) that sample the intestinal lumen are among the first cells encountered by s. t ...200818397382
disinfectant test against monoculture and mixed-culture biofilms composed of technological, spoilage and pathogenic bacteria: bactericidal effect of essential oil and hydrosol of satureja thymbra and comparison with standard acid-base sanitizers.to assess the antimicrobial action of three natural-derived products (essential oil, decoction and hydrosol of satureja thymbra) against biofilms, composed of useful, spoilage and pathogenic bacteria (formed as monoculture or/and mixed-culture), and to compare their efficiency with three standard acid and alkaline chemical disinfectants.200818217930
virulent salmonella enterica infections can be exacerbated by concomitant infection of the host with a live attenuated s. enterica vaccine via toll-like receptor 4-dependent interleukin-10 production with the involvement of both trif and myd88.during systemic disease in mice, salmonella enterica grows intracellularly within discrete foci of infection in the spleen and liver. in concomitant infections, foci containing different s. enterica strains are spatially separated. we have investigated whether functional interactions between bacterial populations within the same host can occur despite the known spatial separation of the foci and independence of growth of salmonellae residing in different foci. in this study we have demonstrated ...200818217948
isolation of avian strains of salmonella enterica serovar typhimurium from cats with enteric disease in the united kingdom. 200818223269
molecular evolution of salmonella enterica serovar typhimurium and pathogenic escherichia coli: from pathogenesis to therapeutics.salmonella enterica serovar typhimurium (s. typhimurium) and certain escherichia coli are human pathogens that have evolved through the acquisition of multiple virulence determinants by horizontal gene transfer. similar genetic elements, as pathogenicity islands and virulence plasmids, have driven molecular evolution of virulence in both species. in addition, the contribution of prophages has been recently highlighted as a reservoir for pathogenic diversity. characterization of horizontally acqu ...200818226587
braun lipoprotein (lpp) contributes to virulence of yersiniae: potential role of lpp in inducing bubonic and pneumonic plague.yersinia pestis evolved from y. pseudotuberculosis to become the causative agent of bubonic and pneumonic plague. we identified a homolog of the salmonella enterica serovar typhimurium lipoprotein (lpp) gene in yersinia species and prepared lpp gene deletion mutants of y. pseudotuberculosis ypiii, y. pestis kim/d27 (pigmentation locus minus), and y. pestis co92 with reduced virulence. mice injected via the intraperitoneal route with 5 x 10(7) cfu of the deltalpp kim/d27 mutant survived a month, ...200818227160
in vitro model of colonization resistance by the enteric microbiota: effects of antimicrobial agents used in food-producing animals.a bioassay was developed to measure the minimum concentration of an antimicrobial drug that disrupts the colonization resistance mediated by model human intestinal microbiota against salmonella invasion of caco-2 intestinal cells. the bioassay was used to measure the minimum disruptive concentrations (mdcs) of drugs used in animal agriculture. the mdcs varied from 0.125 microg/ml for some broad-spectrum antimicrobial drugs (e.g., streptomycin) to 16 microg/ml for drugs with limited spectra of an ...200818227184
distinct functional domains of the salmonella enterica wbap transferase that is involved in the initiation reaction for synthesis of the o antigen subunit.wbap is a membrane enzyme that initiates o antigen synthesis in salmonella enterica by catalysing the transfer of galactose 1-phosphate (gal-1-p) onto undecaprenyl phosphate (und-p). wbap possesses at least three predicted structural domains: an n-terminal region containing four transmembrane helices, a large central periplasmic loop, and a c-terminal domain containing the last transmembrane helix and a large cytoplasmic tail. in this work, we investigated the contribution of each region to wbap ...200818227248
the yejabef operon of salmonella confers resistance to antimicrobial peptides and contributes to its virulence.pathogenic micro-organisms have evolved many strategies to counteract the antimicrobial peptides (amps) that they encounter upon entry into host systems. these strategies play vital roles in the virulence of pathogenic micro-organisms. the salmonella enterica serovar typhimurium genome has a gene cluster consisting of yeja, yejb, yeje and yejf genes, which encode a putative atp-binding cassette (abc) transporter. our study shows that these genes constitute an operon. we deleted the yejf gene, wh ...200818227269
high level ciprofloxacin resistance in salmonella enterica isolated from blood.over the last few years, resistance to ciprofloxacin in salmonella enterica has become a global concern. the present study was undertaken to find out the susceptibility pattern of salmonella enterica isolates in our hospital.200818227598
role of enteric fever in ileal perforations: an overstated problem in tropics?to determine the role of enteric fever in ileal perforations.200818227599
characterisation of salmonella enterica serotype typhimurium isolates from wild birds in northern england from 2005 - 2006.several studies have shown that a number of serovars of salmonella enterica may be isolated from wild birds, and it has been suggested that wild birds may play a role in the epidemiology of human and livestock salmonellosis. however, little is known about the relationship between wild bird s. enterica strains and human- and livestock- associated strains in the united kingdom. given the zoonotic potential of salmonellosis, the main aim of this study was to investigate the molecular epidemiology o ...200818230128
label-free detection of dna with interdigitated micro-electrodes in a fluidic cell.we investigate the analytical performance of an interdigitated electrode sensor for the label-free detection of dna, by monitoring the complex impedance of 5 microm wide interdigitated pt microelectrodes on a glass substrate. we detect the hybridization of unlabeled 38-mer target ssdna with a complementary probe that is bound on the glass in between the electrodes by a disuccinimidyl terephtalate and aminosilane immobilization procedure. the sensor is mounted in a microfluidic flow cell, in whic ...200818231670
an oral recombinant vaccine in dogs against echinococcus granulosus, the causative agent of human hydatid disease: a pilot study.dogs are the main source of human cystic echinococcosis. an oral vaccine would be an important contribution to control programs in endemic countries. we conducted two parallel experimental trials in morocco and tunisia of a new oral vaccine candidate against echinococcus granulosus in 28 dogs. the vaccine was prepared using two recombinant proteins from adult worms, a tropomyosin (egtrp) and a fibrillar protein similar to paramyosin (ega31), cloned and expressed in a live attenuated strain of sa ...200818235847
microbiological profile of greenhouses in a farm producing hydroponic tomatoes.produce, including tomatoes, has been implicated in several outbreaks of foodborne illness. a number of the sources of contamination for produce grown in open fields are known. however, as an alternative agricultural system, hydroponic greenhouses are reasonably expected to reduce some of these sources. the objective of the present study was to determine the microbiological profile of tomatoes grown in greenhouses at a mexican hydroponic farm with a high technological level and sanitary agricult ...200818236663
antimicrobial properties of milkfat globule membrane fractions.milkfat globule membranes (mfgms) were prepared from bovine cream according to standard procedures. these membranes and peptide hydrolysates, which were generated by proteolysis with immobilized digestive enzymes, were screened for antibacterial activity against escherichia coli o157:h7, listeria monocytogenes, salmonella enterica typhimurium, pseudomonas fluorescens, bacillus cereus, lactobacillus acidophilus, and lactobacillus gasseri. assays were first performed on beef heart infusion (bhi) p ...200818236672
using salmonella enterica serotype typhimurium to model intestinal fibrosis. 200818242605
the range of influence between cattle herds is of importance for the local spread of salmonella dublin in denmark.the objective of the study was to estimate the range of influence between cattle herds with positive salmonella dublin herd status. herd status was a binary outcome of high/low antibody levels to salmonella dublin in bulk-tank milk and blood samples collected from all cattle herds in denmark for surveillance purposes. two methods were used. initially, a spatial generalised linear mixed model was developed with an exponential correlation function to estimate the range of influence simultaneously ...200818242741
vaccines and immunotherapy against pseudomonas aeruginosa.a number of different vaccines and several monoclonal antibodies have been developed in the last decades for active and passive vaccination against the gram-negative opportunistic pathogen pseudomonas aeruginosa. these approaches include vaccine antigens such as lipopolysaccharide, surface polysaccharides, polysaccharide-protein conjugates, flagella, outer membrane proteins, pili, whole formalin-killed p. aeruginosa cells, live-attenuated p. aeruginosa and salmonella enterica strains expressing ...200818242792
biofilm formation in field strains of salmonella enterica serovar typhimurium: identification of a new colony morphology type and the role of sgi1 in biofilm formation.in this study we examined the extent of biofilm formation in field strains of salmonella enterica serovar typhimurium (s. typhimurium), an important foodborne pathogen. ninety-four field strains of s. typhimurium were tested for their ability to form biofilm and components contributing to its formation. most s. typhimurium strains were highly capable of biofilm formation except for strains of phage type dt2 originating from pigeons. the most efficient biofilm forming strains were those of phage ...200818242887
on-line monitoring of microbial volatile metabolites by proton transfer reaction-mass spectrometry.a method for analysis of volatile organic compounds (vocs) from microbial cultures was established using proton transfer reaction-mass spectrometry (ptr-ms). a newly developed sampling system was coupled to a ptr-ms instrument to allow on-line monitoring of vocs in the dynamic headspaces of microbial cultures. the novel ptr-ms method was evaluated for four reference organisms: escherichia coli, shigella flexneri, salmonella enterica, and candida tropicalis. headspace vocs in sampling bottles con ...200818245241
human salmonella clinical isolates distinct from those of animal origin.the global trend toward intensive livestock production has led to significant public health risks and industry-associated losses due to an increased incidence of disease and contamination of livestock-derived food products. a potential factor contributing to these health concerns is the prospect that selective pressure within a particular host may give rise to bacterial strain variants that exhibit enhanced fitness in the present host relative to that in the parental host from which the strain w ...200818245251
coordinated regulation of expression of salmonella pathogenicity island 1 and flagellar type iii secretion systems by atp-dependent clpxp protease.salmonella enterica serovar typhimurium delivers a variety of proteins via the salmonella pathogenicity island 1 (spi1)-encoded type iii secretion system into host cells, where they elicit several physiological changes, including bacterial invasion, macrophage apoptosis, and enteropathogenesis. once salmonella has established a systemic infection, excess macrophage apoptosis would be detrimental to the pathogen, as it utilizes macrophages as vectors for systemic dissemination throughout the host ...200818245288
identification of salmonella spi-2 secretion system components required for spvb-mediated cytotoxicity in macrophages and virulence in mice.the salmonella spvb protein possesses adp-ribosyl transferase activity. spvb, acting as an intracellular toxin, covalently modifies monomeric actin, leading to loss of f-actin filaments in salmonella-infected human macrophages. using defined salmonella mutants, different functional components of the spi-2 type three secretion system (ttss), ssav, spic, sseb, ssec, and ssed, were found to be required for spvb-mediated actin depolymerization in human macrophages. expression of spvb protein in salm ...200818248436
secreted enteric antimicrobial activity localises to the mucus surface layer.the intestinal mucosa is constantly exposed to a dense and highly dynamic microbial flora and challenged by a variety of enteropathogenic bacteria. antibacterial protection is provided in part by paneth cell-derived antibacterial peptides such as the alpha-defensins. the mechanism of peptide-mediated antibacterial control and its functional importance for gut homeostasis has recently been appreciated in patients with crohn's ileitis. in the present study, the spatial distribution of antimicrobia ...200818250125
transduction of bla(cmy-2), tet(a), and tet(b) from salmonella enterica subspecies enterica serovar heidelberg to s. typhimurium.antimicrobial resistance of salmonella spp., especially resistance mediated by extended spectrum beta-lactamases (esbl), is a growing public health concern. understanding the mechanisms through which salmomella spp. acquire the resistance genes can lead to the development of intervention and mitigation strategies. thirty-one salmonella isolates of bovine origin were analyzed by serotyping, antimicrobial susceptibility testing, phage induction and bacterial host range determination, and phage tra ...200818187273
diseases and reproductive success in a wild mammal: example in the alpine chamois.density-dependent and climatic factors affect reproduction and dynamics of wild ungulates. parasites can also decrease reproductive success through either a direct abortive effect or a negative impact on host growth and body condition. however, few studies have investigated the effect of parasitism on fecundity of ungulates in natural conditions. we studied three bacterial infections caused by salmonella enterica serovar abortusovis, chlamydophila abortus and coxiella burnetii. these bacteria ar ...200818189146
molecular characterization of the salmonella enterica serovar typhi vi-typing bacteriophage e1.some bacteriophages target potentially pathogenic bacteria by exploiting surface-associated virulence factors as receptors. for example, phage have been identified that exhibit specificity for vi capsule producing salmonella enterica serovar typhi. here we have characterized the vi-associated e1-typing bacteriophage using a number of molecular approaches. the absolute requirement for vi capsule expression for infectivity was demonstrated using different vi-negative s. enterica derivatives. the p ...200818192390
biosynthesis and iroc-dependent export of the siderophore salmochelin are essential for virulence of salmonella enterica serovar typhimurium.in response to iron deprivation, salmonella enterica serovar typhimurium secretes two catecholate-type siderophores, enterobactin and its glucosylated derivative salmochelin. although the systems responsible for enterobactin synthesis and acquisition are well characterized, the mechanisms of salmochelin secretion and acquisition, as well as its role in salmonella virulence, are incompletely understood. herein we show by liquid chromatography-mass spectrometry analysis of culture supernatants fro ...200818194158
aggregation via the red, dry, and rough morphotype is not a virulence adaptation in salmonella enterica serovar typhimurium.the salmonella rdar (red, dry, and rough) morphotype is an aggregative and resistant physiology that has been linked to survival in nutrient-limited environments. growth of salmonella enterica serovar typhimurium was analyzed in a variety of nutrient-limiting conditions to determine whether aggregation would occur at low cell densities and whether the rdar morphotype was involved in this process. the resulting cultures consisted of two populations of cells, aggregated and nonaggregated, with the ...200818195033
toll-like receptor 5-deficient mice have dysregulated intestinal gene expression and nonspecific resistance to salmonella-induced typhoid-like disease.the recognition of flagellin by toll-like receptor 5 (tlr5) is the dominant means by which model intestinal epithelia activate proinflammatory gene expression in response to salmonella enterica. the role of the flagellin-tlr5 interaction in vivo has been addressed primarily via studies that use flagellar mutants. such studies suggest that host recognition of flagellin promotes rapid neutrophil recruitment that protects the host from this pathogen. however, these works do not directly address the ...200818195036
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