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glycogen: biosynthesis and regulation.the accumulation of glycogen occurs in escherichia coli and salmonella enterica serovar typhimurium as well as in many other bacteria. glycogen will be formed when there is an excess of carbon under conditions in which growth is limited due to the lack of a growth nutrient, e.g., a nitrogen source. the structural genes of the glycogen biosynthetic enzymes of e. coli and s. serovar typhimurium have been cloned previously, and that has provided insights in the genetic regulation of glycogen synthe ...200926443753
profile of culture positive enteric fever from bangalore.enteric fever is endemic in india. the aim of this study was to analyse the clinical, laboratory, antibiotic sensitivity profile and response to antibiotics of culture positive enteric fever patients from bangalore.200927408286
the contribution of genes required for anaerobic respiration to the virulence of salmonella enterica serovar gallinarum for chickens.salmonella enterica serovar gallinarum (sg) is an intracellular pathogen of chickens. to survive, to invade and to multiply in the intestinal tract and intracellularly it depends on its ability to produce energy in anaerobic conditions. the fumarate reductase (frdabcd), dimethyl sulfoxide (dmso)-trimethylamine n-oxide (tmao) reductase (dmsabc), and nitrate reductase (narghij) operons in salmonella typhimurium (stm) encode enzymes involved in anaerobic respiration to the electron acceptors fumara ...200924031452
a defective mutant of salmonella enterica serovar gallinarum in cobalamin biosynthesis is avirulent in chickens.salmonella enterica serovar gallinarum (sg) is a fowl typhoid agent in chickens and is a severe disease with worldwide economic impact as its mortality may reach up to 80%. it is one of a small group of serovars that typically produces typhoid-like infections in a narrow range of host species and which therefore represents a good model for human typhoid. the survival mechanisms are not considered to be virulent mechanisms but are essential for the life of the bacterium. mutants of salmonella gal ...200924031393
molecular differentiation between salmonella enterica subsp enterica serovar pullorum and salmonella enterica subsp enterica serovar gallinarum.s. pullorum (sp) and s. gallinarum (sg) are very similar. they are the agents of pullorum disease and fowl typhoid, respectively, and the two diseases are responsible for economic losses in poultry production. although sp and sg are difficult to be differentiated in routine laboratory procedures, the ability to metabolize ornithine is a biochemical test that may be used to achieve this aim. while sp is able to decarboxylate this amino acid, sg is not. however, the isolation of strains showing at ...200924031341
inhibition of salmonella enterica cells in deli-type salad by enterocin as-48 in combination with other antimicrobials.the cyclic antibacterial peptide enterocin as-48 acted synergistically with p-hydroxybenzoic acid methyl ester (phbme) and with 2-nitropropanol against salmonella enterica serovar enteritidis cect 4300 in russian salad. in challenge tests on a cocktail of salmonella strains (s. enterica ssp. enterica serotype typhi cect 409, s. enterica ssp. enterica serovar choleraesuis cect 915, s. enterica ssp. enterica serovar enteritidis cect 4300, s. enterica ssp. arizonae serovar arizonae cect 4395, and s ...200926783134
control of salmonella enterica serovar enteritidis in laying hens by inactivated salmonella enteritidis vaccines.salmonella enteritidis is one of the agents that is responsible for outbreaks of human foodborne salmonellosis caused by salmonella enteritidis and is generally associated with the consumption of poultry products. inactivated salmonella enteritidis cell vaccine is one of the available methods to control salmonella enteritidis in breeders and laying hens, however results in terms of efficacy vary. this vaccine has never been tested in brazil, therefore, the present work was carried out to assess ...200824031235
cytotoxic t cell adjuvant effects of three salmonella enterica flagellins.bacterial flagellins are important virulence-associated factors and strong inducers of inflammatory responses in mammalian hosts. flagellins have also been investigated as potential vaccine adjuvants, either for induction of humoral or cellular immune responses, to different target antigens. in this study we investigated the adjuvant properties of three salmonella enterica flagellins types (flicd, flici and fljb) to an ovalbumin-derived cd8(+) t cell-restricted epitope (ova257-264). although mic ...200824031176
the aerobic and anaerobic respiratory chain of escherichia coli and salmonella enterica: enzymes and energetics.escherichia coli contains a versatile respiratory chain which oxidizes ten different electron donor substrates and transfers the electrons to terminal reductases or oxidases for the reduction of six different electron acceptors. salmonella is able to use even two more electron acceptors. the variation is further increased by the presence of isoenzymes for some substrates. various respiratory pathways can be established by combining the oxidation of different electron donors and acceptors which a ...200826443736
biosynthesis and use of cobalamin (b12).this review summarizes research performed over the last 23 years on the genetics, enzyme structures and functions, and regulation of the expression of the genes encoding functions involved in adenosylcobalamin (adocbl, or coenzyme b12) biosynthesis. it also discusses the role of coenzyme b12 in the physiology of salmonella enterica serovar typhimurium lt2 and escherichia coli. john roth's seminal contributions to the field of coenzyme b12 biosynthesis research brought the power of classical and ...200826443728
magnesium transport and magnesium homeostasis.this review reviews the properties and regulation of the salmonella enterica serovar typhimurium and escherichia coli transporters that mediate mg2+ influx: cora and the mgt p-type atpases. in addition, potential mg2+ regulation of transcription and translation, largely via the phopq two component system, is discussed. cora proteins are a unique class of transporters and are widespread in the bacteria and archaea, with rather distant but functional homologs in eukaryotes. the mgt transporters ar ...200826443723
investigation of an outbreak of salmonella enterica subsp. enterica serovar hadar food illness in the abruzzi region of italy.a comparative study was made of 22 strains of salmonella hadar isolated from victims of an outbreak of food illness in the abruzzi region of italy in 2000 and 21 strains of the same serotype isolated from poultry meat and human stool samples in the abruzzi and molise regions between 2000 and 2001. the aim of the investigation was to provide an epidemiological interpretation of the food illness outbreak to establish the degree of similarity between the s. hadar strains isolated from victims of th ...200820405442
comparative study of leaf and stem bark extracts of parkia biglobosa against enterobacteria.hydroethanolic and aqueous extracts of leaf and stem bark of parkia biglobosa (jacq) benth. (mimosaceae) were tested against clinical isolates escherichia coli, salmonella typhi, shigella dysenteriae and enterococcus faecalis, and corresponding collection strains e. coli cip 105 182, salmonella enterica cip 105 150, shigella dysenteriae cip 54-51 and enterococcus faecalis cip 103 907. discs of gentamicin, a broad spectrum antibiotic were used as positive controls. the results showed that all the ...200820161943
regulation of vi capsular polysaccharide synthesis in salmonella enterica serotype typhi.the synthesis of vi polysaccharide, a major virulence determinant in salmonella enterica serotype typhi (s. typhi), is under the control of two regulatory systems, ompr-envz and rscb-rscc, which respond to changes in osmolarity. some s. typhi isolates exhibit over-expression of vi polysaccharide, which masks clinical detection of lps o-antigen. this variation in vi polysaccharide and o-antigen display (vw variation) has been observed since the initial studies of s. typhi. we have reported that t ...200819745516
the laboratory diagnosis of enteric fever.the diagnosis of enteric fever currently depends upon the isolation of salmonella from a patient, most commonly by blood culture. this facility is not available in many areas where the disease is endemic. serodiagnosis depends upon the 100-year-old widal test, and other serological diagnostic tools have limitations because of their low sensitivity and/or specificity. the most promising recently published results are from pcr-based amplification of dna from the blood of enteric fever patients but ...200819745517
treatment of enteric fever.enteric fever is systemic illness caused by salmonella typhi and salmonella paratyphi a, b and c. it is believed to be a readily treatable illness by many clinicians in the developing world where it is endemic; however, with the emergence of drug resistance to fluoroquinolones, treatment is becoming increasingly difficult. while drugs such as cefixime, previously believed to be effective, have been proven otherwise, new agents such as gatifloxacin and azithromycin have proven to be promising. re ...200819745518
typhi genes expressed during infection or involved in pathogenesis.salmonella enterica serovar typhi (typhi), the aetiologic agent of typhoid fever, is a human restricted pathogen. elucidation of the interactions between the infected host and this pathogen is critical to understand infectious diseases but is deterred by a lack of in vivo infection assays, since typhi uniquely infects humans and there is no suitable animal model. macrophages can be used as an alternative model, as the ability to survive and replicate within these cells is thought to be one of th ...200819745519
invasive salmonellosis in malawi.the incidence of invasive salmonellosis has increased among children and hiv-infected adults in malawi. this has been associated with the emergence of drug resistance in the non-typhoidal salmonella serovars enteritidis and typhimurium. in contrast, s. typhi isolates have remained fully sensitive to commonly used antibiotics and the estimated incidence of typhoid fever, although still present, has fallen slightly among both adults and children. infection with s. typhi is not closely associated w ...200819745520
typhoid fever in sub-saharan africa: challenges of diagnosis and management of infections.typhoid fever, caused by salmonella enterica serovar typhi (s. typhi), is a disease transmitted by the faecal-oral route. it continues to be a public health problem in many developing countries in sub-saharan africa. school-age children, especially those from resource-poor settings with inadequate water and sanitation systems, are disproportionately affected. it is estimated that a total of 400,000 cases occur annually in africa, an incidence of 50 per 100,000 persons per year. lack of effective ...200819745521
typhoid fever in ethiopia.this review focuses on the reports of salmonellosis by investigators in different parts of ethiopia, in particular focusing on the levels of typhoid fever. many of the reports are published in local journals that are not available online. there have been seven studies which diagnosed typhoid fever by laboratory culture and there is no coordinated epidemiological surveillance. all conducted research and reports from different health institutions in ethiopia indicate that typhoid fever was still a ...200819745522
epidemiology of typhoid and paratyphoid fever in india.enteric fever (typhoid and paratyphoid fever) is a major human bacterial infection. although the disease is not common in industrialised countries, it remains an important and persistent health problem in developing nations. hospital-based studies and outbreak reports from india indicate that enteric fever is a major public health problem in this country, with salmonella enterica serovar typhi (s. typhi) the most common aetiologic agent but with an apparently increasing number of cases due to s. ...200819745523
clinical pathogenesis of typhoid fever.human infections with salmonella enterica results in two major groups of diseases: gastroenteritis and typhoid fever. clinical observations suggest that gastroenteritis, caused by non-typhoidal salmonella serovars, is characterized by a massive neutrophil influx, which keeps the infection localized to the intestinal mucosa. in contrast, the absence of neutrophilic intestinal infiltrates in the acute phase of typhoid fever suggests a propensity for typhoidal salmonella serovars (s. typhi, s. para ...200819741286
spi-7: salmonella's vi-encoding pathogenicity island.salmonella pathogenicity island-7 (spi-7) is a large, mosaic, genetic island, found in several serovars of salmonella enterica subsp. enterica associated with systemic disease. as well as encoding genes which may aid its own transmission, it carries genes for potential virulence factors such as vi antigen, sope effector and type ivb pili. the stability of spi-7 is of interest with respect to typhoid fever and related vaccines.200819741287
inchi plasmids, a dynamic link between resistance and pathogenicity.plasmids of incompatibility group (inc) hi1 are important vectors of antibiotic resistance in both of the major causal agents of enteric fever: salmonella enterica subspecies enterica serovar typhi and s. paratyphi a. in s. typhi, inchi1 plasmids appeared in the 1970s and spread globally. in some circumstances they are maintained within the bacterial population even in the absence of selection from antibiotics. the low cost associated with inch plasmids in salmonella is due, in part, to the pres ...200819741288
enteric fever in south china: guangxi province.guangxi is a province of china endemic for enteric fever. salmonella enterica serovar paratyphi a has been found to be causing more and more enteric fever episodes in the last 10 years, evident not only from routine surveillance but also from prospective population-based surveillance. the prevalent pattern of paratyphoid seen was different from typhoid since it mainly occurred in outbreaks. almost all strains collected from different areas and years in guangxi were resistance to nalidixic acid, ...200819741290
antibiotic resistance among salmonella enterica serovars typhi and paratyphi a in pakistan (2001-2006).to compare antimicrobial resistance in s. typhi and s. paratyphi a isolates from pakistan.200819741291
emergence of plasmid-mediated multidrug resistance in epidemic and non-epidemic strains of salmonella enterica serotype typhi from jordan.enteric fever caused by salmonella enterica serovar typhi has not been adequately explored in jordan.200819741292
association of carcinoma of the gallbladder with typhoid carriage in a typhoid endemic area using nested pcr.although well studied the association between chronic typhoid carrier state and carcinoma of the gallbladder (cagb) remains unproven.200819741293
mimotopes of heat shock proteins of salmonella enterica serovar typhi identified from phage-displayed peptide library.heat shock proteins (hsps) are known to be involved in the pathogenesis of salmonella enterica serovar typhi (s. typhi), the causative agent of typhoid fever. the objective of this study was to apply a phage display library to identify mimotopes of two hsps, hsp90 and dnak in s. typhi.200819741295
a case report and review of the literature: ciprofloxacin resistant salmonella enterica serovar typhi in india.enteric fever is a major public health problem in india. the current treatment of choice is the fluoroquinolones.200819741296
intestinal mmc-related electric fields and pancreatic juice control the adhesion of gram-positive and gram-negative bacteria to the gut epithelium--in vitro study.the adhesion of six different lactobacillus and lactococcus and three pathogenic escherichia and salmonella strains was studied using caco-2 cell line. in this in vitro model system the influence of weak electric field (ef) on bacterial adhesion was tested. the ef source was the in vitro reconstruction of spiking potentials recorded in the duodenum of a healthy calf during one myoelectrical migration complex (mmc) cycle. the ability to adhere to caco-2 cells of bacteria belonging to two groups, ...200819212012
construction of highly attenuated salmonella enterica serovar typhimurium live vectors for delivering heterologous antigens by chromosomal integration.attenuated live salmonella enterica serovar typhimurium is a versatile organism for the generation of live recombinant vaccines for mucosal immunization and various approaches were devised for the stable and efficient expressions of heterologous antigens by attenuated s. enterica strains. phage lamda red recombinase has recently been devised for gene replacements in s. enterica after introduction of pcr products as a one-step deletion approach and flp-mediated recombination allows the subsequent ...200819216101
effect of hemidesmus indicus r.br. root extract against salmonella enterica serovar typhimurium-induced apoptosis in murine macrophage cell line (p388d1).previous studies on natural products had mainly dealt with their antimicrobial activity and studies on the interference of these bioactive compounds with host-bacterial interaction is limited. the present study was undertaken to investigate the effect of the sterols and fatty acids present in the chloroform fraction of crude methanol extract of hemidesmus indicus root (chi) on salmonella enterica serovar typhimurium (s. typhimurium) mediated apoptosis in a murine macrophage cell line (p388d1).200819179687
salmonella administration induces a reduction of wheel-running activity via a tlr5-, but not a tlr4, dependent pathway in mice.in general, systemic bacterial infections induce sickness behavior. in mice, lipopolysaccharide (lps), a component of gram-negative bacteria, strongly reduces physical activity via toll-like receptor (tlr) 4. however, gram-negative bacteria, such as salmonella, also express flagella containing flagellin (fg) which binds to tlr5 and induces pro-inflammatory cytokine production. it is unclear whether fg induces sickness behavior. to determine whether salmonella administration regulates the reducti ...200819203083
[application of pulsed-field gel electrophoresis in a food-borne outbreak of salmonella serotype muenchen infection].to investigate the application of pulsed-field gel electrophoresis (pfge) in food-borne outbreak.200819176144
rapid real-time pcr assay for detecting salmonella in raw and ready-to-eat meats.a real-time pcr assay was evaluated for the rapid detection (10 h) of salmonella in meats using molecular beacon probes available as a commercial kit (iq-check, bio-rad laboratories). raw (chicken, pork) and ready-to-eat (rte) meats were artificially contaminated with salmonella enterica serovar typhimurium at the estimated level of 2 to 4 cells per 25 g. after 8 h of pre-enrichment in buffered peptone water, a molecular beacon-based pcr assay was performed to detect contamination in raw and rte ...200819149100
phage type and antimicrobial susceptibility of salmonella enterica serovar enteritidis from food-producing animals in japan between 1976 and 2004.a total of 56 isolates of salmonella enterica serovar enteritidis, including 38 isolates from poultry, 16 from cattle and two from pigs, collected between 1976 and 2004, were subjected to bacteriophage typing and antimicrobial susceptibility testing. phage type (pt) 8 was predominant in bovine isolates, whereas pt1 and pt4 were predominant in poultry isolates. resistance was found for 8 of 11 antimicrobials tested, at the following rates: 46.4% for dihydrostreptomycin followed by ampicillin and ...200819123313
typhoid fever in southern taiwan: a medical center experience.typhoid fever is caused by salmonella enterica serotype typhi (5. typhi). growing communication between taiwan and neighboring regions in recent years could be an important source of typhoid fever. the aim of this study was to analyze the clinical characteristics of typhoid fever treated at a medical center in southern taiwan.200819054916
[mechanism of interaction of tumor necrosis factor (tnf-alpha) of macroorganism with the salmonella enterica cells (ser. typhimurium)].the goal of this work was to elucidate the mechanism of direct interaction of bacterial cells with tumor necrosis factor (tnf-alpha; cytokine). it was shown earlier that this interaction facilitated activation of bacterial growth and recultivation of non-cultivated forms in vitro and in vivo. it was shown in experiments with mice deficient in the genes encoding eucaryotic tnf-alpha receptors and infected with salmonella that addition of exogenous tnf-alpha to suspension of infection cells caused ...200819172874
[report on typhoid fever case in maringá, state of paraná].typhoid fever is an acute bacterial disease caused by salmonella enterica serotype typhi, which is acquired by consumption of contaminated food or water. this paper had the aim of describing a case of typhoid fever that occurred in maringá, state of paraná, after three years without any notifications of the disease.200819142452
transmission of salmonella between wildlife and meat-production animals in denmark.to investigate the transmission of salmonella spp. between production animals (pigs and cattle) and wildlife on production animal farms in denmark.200819146492
effects of repeated cycles of acid challenge and growth on the phenotype and virulence of salmonella enterica.the aim of the study was to investigate how stresses like low ph, which may be encountered in farms or food preparation premises, shape populations of salmonella enterica by the selection of stress-resistant variants.200819146498
bacteriological detection of salmonella enteritidis in eggs: a review.the detection of salmonella enterica serovar enteritidis (se) in eggs is hampered by a typically low prevalence of contaminated eggs, the low number of se organisms in such eggs, and the presence of inhibitory substances in the egg albumin. for these reasons, the analysis of large pools of eggs is normally necessary, which presents logistic and microbiological challenges associated with a low number of target organisms from a large volume of sample matrix. in some studies using artificially inoc ...200819284035
cross-protective effect of acid-adapted salmonella enterica on resistance to lethal acid and cold stress conditions.to evaluate the cross-protected salmonella enterica cells under acid and cold stress conditions.200819241522
salmonella sofia differs from other poultry-associated salmonella serovars with respect to cell surface hydrophobicity.salmonella enterica is one of the most important foodborne pathogens. salmonella enterica subsp. ii 4,12:b:- (salmonella sofia) is commonly found in australian poultry. it has been suggested that physicochemical properties such as surface charge and hydrophobicity may affect bacterial attachment to surfaces and their ability to persist in food systems. a possible link between hydrophobicity cell surface charge and persistence of salmonella from the poultry system was examined. hydrophobicity of ...200819244894
splenic abscess due to salmonella enterica serotype typhi in a young adult. 200819245162
evaluation of genome-derived amplicon length polymorphism pcr primers for the genetic evaluation of related strains of salmonella.the intent of this study is to exploit both the genetic diversity and conservation demonstrated between the salmonella enterica ssp. enterica serovar typhi ct18 and salm. enterica ssp. enterica serovar typhimurium lt2 genomes by utilizing amplicon length polymorphism (alp) to detect and differentiate various salmonella strains.200819552779
genotyping and antimicrobial susceptibility of salmonella enterica serotype panama isolated in taiwan.previous studies have indicated that salmonella enterica serotype panama causes systemic infections in humans. the present study was undertaken to gain more understanding of the molecular epidemiology and antimicrobial resistance of salmonella panama.200819255695
rapid detection of salmonella in foods using real-time pcr.conventional methods for detection of salmonella serovars in foods are generally time-consuming and labor intensive. a real-time pcr method has been developed with custom designed primers and a taqman probe to detect the presence of a 262-bp fragment of the salmonella-specific inva gene. the method has been tested with a total of 384 field-isolated salmonella serovars and non-salmonella stock strains, as well as 420 u.s. food and drug administration food samples, comprising a variety of food mat ...200819256088
dna recognition by the salmonella enterica serovar typhimurium transcription factor slya.the salmonella regulatory protein slya is implicated in virulence, survival in macrophages and resistance to oxidative stress and anti-microbial peptides. slya is a member of the marr family of winged-helix transcription factors. systematic mutational analysis of the slya operator sequence and of the predicted dna-binding region of slya shows that no single base pair in the palindromic slya operator sequence is essential for dna binding, and identifies amino acid residues required to allow slya ...200819204896
multidrug resistance of salmonella enterica serovars typhi and typhimurium isolated from clinical samples at two rural hospitals in western kenya.the threat to human health posed by antibiotic resistance is of growing concern. many commensals and pathogenic organisms have developed resistance to well established and newer antibiotics. this is a cross-sectional study within two hospital settings to determine in vitro antibiotic susceptibilities of salmonella species isolated in blood, cerebral spinal fluid, pus and stool collected from in- and out-patients. the inclusion criteria was non restrictive to in- and out-patient but preference to ...200819738333
development of an oligonucleotide microarray method for salmonella serotyping.adequate identification of salmonella enterica serovars is a prerequisite for any epidemiological investigation. this is traditionally obtained via a combination of biochemical and serological typing. however, primary strain isolation and traditional serotyping is time-consuming and faster methods would be desirable. a microarray, based on two housekeeping and two virulence marker genes (atpd, gyrb, flic and fljb), has been developed for the detection and identification of the two species of sal ...200821261872
experimental reproduction of bovine salmonella encephalopathy using a norepinephrine-based stress model.neurological disease represents a sporadic but serious manifestation of bovine salmonellosis that is thought to be related to systemic infection. salmonella enterica serovar dublin (s. dublin) is the serovar most associated with systemic infection in cattle, although reports of neurological disease associated with s. dublin or any other serovar are rare and usually anecdotal. this study reports the involvement of three strains of s. enterica, serovars saintpaul, montevideo, and enteritidis, in s ...200817324598
comparison of growth phase on salmonella enterica serovar typhimurium invasion in an epithelial cell line (ipec j2) and mucosal explants from porcine small intestine.salmonella typhimurium dt104 is a zoonotic enteropathogen of increasing concern for human health. in this study, the influence of growth phase on invasiveness of a s. typhimurium dt104 field isolate and two reference strains (sl1344 and atcc 14028) was compared in ipec j2 cells and mucosal explants from porcine ileum. internalized bacteria were quantified by a gentamicin resistance assay. after 90 min of exposure to the apical aspect of epithelial monolayers or luminal surface of explants, inter ...200817544508
molecular typing of salmonella enterica serovars enteritidis, corvallis, anatum and typhimurium from food and human stool samples in tunisia, 2001-2004.during the period from 2001 to 2004, a total of 72 isolates of salmonella enterica serovars: anatum (n=40), enteritidis (n=18), corvallis (n=8), and typhimurium (n=6), of various origins (mainly food and diarrhoeagenic stool samples), were collected and further characterized by antibiotic resistance, plasmid analysis, and pulsed-field gel electrophoresis (pfge). forty-five isolates presented multidrug resistance to antibiotics. among which one s. enterica serovar anatum isolate was resistant to ...200817568477
mutations in the tryptophan operon allow purf-independent thiamine synthesis by altering flux in vivo.phosphoribosyl amine (pra) is an intermediate in purine biosynthesis and also required for thiamine biosynthesis in salmonella enterica. pra is normally synthesized by phosphoribosyl pyrophosphate amidotransferase, a high-turnover enzyme of the purine biosynthetic pathway encoded by purf. however, purf-independent pra synthesis has been observed in strains having different genetic backgrounds and growing under diverse conditions. genetic analysis has shown that the anthranilate synthase-phosphor ...200817557816
pathogen specific carbohydrate antigen microarrays: a chip for detection of salmonella o-antigen specific antibodies.a salmonella o-antigen microarray was developed by covalent coupling of oligosaccharide antigens specific for serogroups salmonella enterica sv. paratyphi (group a), typhimurium (group b) and enteritidis (group d). antibodies were correctly detected in sera from patients with culture verified salmonellosis. high serogroup-specificity was seen with the disaccharide antigens. with the larger antigens, containing the backbone sequence manalpha1-2rhaalpha1-2gal (mrg), common backbone-specific antibo ...200817558551
salmonella enterica serotype typhimurium carrying hybrid virulence-resistance plasmids (puo-stvr): a new multidrug-resistant group endemic in spain.the epidemiological impact in spain of an emerging group of multidrug-resistant salmonella enterica serotype typhimurium, characterized by the presence of virulence-resistance hybrid plasmids (termed puo-stvr) that are related to the s. typhimurium virulence plasmid pslt, was evaluated. adscription to the group was based on detection of the bla(oxa-1) gene (encoding ampicillin resistance) by pcr, and identification of a puo-stvr plasmid through hybridization with specific probes for virulence (s ...200817597002
the distribution of acetohydroxyacid synthase in soil bacteria.most bacteria possess the enzyme acetohydroxyacid synthase, which is used to produce branched-chain amino acids. enteric bacteria contain several isozymes suited to different conditions, but the distribution of acetohydroxyacid synthase in soil bacteria is largely unknown. growth experiments confirmed that escherichia coli, salmonella enterica serotype typhimurium, and enterobacter aerogenes contain isozymes of acetohydroxyacid synthase, allowing the bacteria to grow in the presence of valine (w ...200817624809
stec is a salmonella kinase required for spi-2-dependent f-actin remodelling.salmonella enterica serovar typhimurium (s. typhimurium) replicates inside mammalian cells within membrane-bound compartments called salmonella-containing vacuoles. intracellular replication is dependent on the activities of several effector proteins translocated across the vacuolar membrane by the salmonella pathogenicity island 2 (spi-2)-type iii secretion system (t3ss). this is accompanied by the formation in the vicinity of bacterial vacuoles of an f-actin meshwork, thought to be involved in ...200817645553
part i. analysis of data gaps pertaining to salmonella enterica serotype typhi infections in low and medium human development index countries, 1984-2005.there are only 10 contemporary, population-based studies of typhoid fever that evaluate disease incidence using blood culture for confirmation of cases. reported incidence ranged from 13 to 976/100 000 persons per year. these studies are likely to have been done preferentially in high- incidence sites which makes generalization of data difficult. only five of these studies reported mortality. of these the median (range) mortality was 0% (0-1.8%). since study conditions usually involved enhanced ...200817686194
improving live attenuated bacterial carriers for vaccination and therapy.live attenuated bacteria are well established as vaccines. thus, their use as carriers for prophylactic and therapeutic macromolecules is a logical consequence. here we describe several experimental applications of bacteria to carry heterologous macromolecules into the murine host. first, listeria monocytogenes are described that are able to transfer eukaryotic expression plasmids into host cells for gene therapy. high multiplicities of infection are still required for efficient gene transfer an ...200817702649
the salmonella enterica serotype typhi regulator tvia reduces interleukin-8 production in intestinal epithelial cells by repressing flagellin secretion.unlike non-typhoidal salmonella serotypes, s. enterica serotype typhi does not elicit neutrophilic infiltrates in the human intestinal mucosa. the vi capsule-encoding tviabcdevexabcde operon (viab locus) is a s. typhi-specific dna region preventing production of interleukin (il)-8 during infection of intestinal epithelial cells. we elucidated the mechanism by which the viab locus reduces il-8 production in human colonic epithelial (t84) cells. a s. typhi tviabcdevexabcde deletion mutant, but not ...200817725646
cytokine gene expression in chicken cecal tonsils following treatment with probiotics and salmonella infection.probiotics are currently employed for control of pathogens and enhancement of immune response in chickens. in this study, we investigated the underlying immunological mechanisms of the action of probiotics against colonization of the chicken intestine by salmonella enterica subsp. enterica serovar typhimurium (salmonella serovar typhimurium). birds received probiotics by oral gavage on day 1 of age and, subsequently, received salmonella serovar typhimurium on day 2 of age. cecal tonsils were rem ...200817681719
bringing order to a complex molecular machine: the assembly of the bacterial flagella.the bacterial flagellum is an example of elegance in molecular engineering. flagella dependent motility is a widespread and evolutionarily ancient trait. diverse bacterial species have evolved unique structural adaptations enabling them to migrate in their environmental niche. variability exists in the number, location and configuration of flagella, and reflects unique adaptations of the microorganism. the most detailed analysis of flagellar morphogenesis and structure has focused on escherichia ...200817719558
clonal diversity of salmonella enterica serotype typhi isolated from patients with typhoid fever in tehran.in this study, antimicrobial susceptibility test and genetic typing were used to characterize 15 salmonella enterica serotype typhi (s. typhi) isolates recovered from sporadic cases of typhoid fever in tehran, iran during 2004. antimicrobial susceptibility test showed that all isolates were susceptible to 20 antimicrobials examined in this study. analysis of insertion elements showed that 2 is200 types with 10 and 11 copies were present. 11 of the 15 isolates were found to possess 10 is200 eleme ...200817852914
structural characterization and serological specificities of lipopolysaccharides from salmonella enterica serovar gallinarum biovar pullorum standard, intermediate and variant antigenic type strains.the structure and serological specificities of the lipopolysaccharides (lpss) from salmonella enterica serovar gallinarum biovar pullorum were studied to provide an improved basis for the distinction between antigenic types and the development of improved diagnostic tests. the structure of the lps o-polysaccharide (o-ps) from s. pullorum standard, intermediate and variant antigenic type strains was determined by mass spectrometry, nuclear magnetic resonance spectroscopy and chemical analysis. th ...200817855026
structural biology of membrane-intrinsic beta-barrel enzymes: sentinels of the bacterial outer membrane.the outer membranes of gram-negative bacteria are replete with integral membrane proteins that exhibit antiparallel beta-barrel structures, but very few of these proteins function as enzymes. in escherichia coli, only three beta-barrel enzymes are known to exist in the outer membrane; these are the phospholipase ompla, the protease ompt, and the phospholipidcolon, two colonslipid a palmitoyltransferase pagp, all of which have been characterized at the structural level. structural details have al ...200817880914
activation of pro-matrix metalloproteinase-9 and degradation of gelatin by the surface protease pgte of salmonella enterica serovar typhimurium.mammalian matrix metalloproteinases (mmps) degrade collagen networks in extracellular matrices by cleaving collagen and its denatured form gelatin, and thus enhance migration of mammalian cells. the gastrointestinal pathogen salmonella enterica survives and grows within host macrophages and dendritic cells, and can disseminate in the host by travelling within infected host cells. here, we report that s. enterica serovar typhimurium activates prommp-9 (gelatinase b) secreted by human primary macr ...200817888724
rational design of salmonella recombinant vaccines.salmonella enterica is an important pathogen of animals and humans causing a variety of infectious diseases. the large number of cases of typhoid fever due to s. enterica serovar typhi infections gives rise to the continuous need for improved vaccines against this life-threatening infection. however, s. enterica is also an interesting organism to act as a live attenuated carrier for the presentation of recombinant heterologous antigens. comprehensive experimental studies have been performed and ...200817888730
effect of norepinephrine on colonisation and systemic spread of salmonella enterica in infected animals: role of catecholate siderophore precursors and degradation products.norepinephrine promotes the growth of salmonella enterica in vitro in iron-restricted conditions imposed by the iron-binding proteins serum transferrin and egg-white ovotransferrin by facilitating the release of bound iron and subsequent uptake by the bacteria. moreover, significantly increased colonisation and systemic spread were observed in mouse and chicken models of s. enterica infection following pre-treatment of animals with norepinephrine. both ent and tonb mutants showed no growth promo ...200817888732
osteoblasts express nlrp3, a nucleotide-binding domain and leucine-rich repeat region containing receptor implicated in bacterially induced cell death.bacterially induced osteoblast apoptosis may be a major contributor to bone loss during osteomyelitis. we provide evidence for the functional expression in osteoblasts of nlrp3, a member of the nlr family of cytosolic receptors that has been implicated in the initiation of programmed cell death.200817907925
emergence of multidrug-resistant salmonella spp. and isolates with reduced susceptibility to ciprofloxacin in kuwait and the united arab emirates.kuwait and united arab emirates (uae) are 2 countries with worldwide significance in the context of global epidemiology of antimicrobial resistance. the extent of drug resistance in salmonella spp. isolated from these countries was investigated by determining their susceptibility to 9 antibiotics using the e-test method. amikacin, cefotaxime, ceftriaxone, ciprofloxacin, and gentamicin had excellent activities against all kuwait and uae isolates with mic(90)s ranging between 0.056 and 4.5 microg/ ...200817931817
amelioratory effects of zinc supplementation on salmonella-induced hepatic damage in the murine model.zinc (zn) has been reported to influence the susceptibility of the host to a diverse range of infectious pathogens, including viruses, bacteria, fungi and protozoa. we report here an evaluation of the effects of zn supplementation on salmonella enterica serovar typhimurium (s. typhimurium)-induced hepatic injury in the murine model. zinc levels in the plasma and liver tissues were measured by atomic absorption spectroscopy. the effect of zn supplementation was evaluated by assessing the bacteria ...200817934836
the salmonella spi1 type three secretion system responds to periplasmic disulfide bond status via the flagellar apparatus and the rcscdb system.upon contact with intestinal epithelial cells, salmonella enterica serovar typhimurium injects a set of effector proteins into the host cell cytoplasm via the salmonella pathogenicity island 1 (spi1) type iii secretion system (t3ss) to induce inflammatory diarrhea and bacterial uptake. the master spi1 regulatory gene hila is controlled directly by three arac-like regulators: hild, hilc, and rtsa. previous work suggested a role for dsba, a periplasmic disulfide bond oxidase, in spi1 t3ss function ...200817951383
gastrointestinal microbial ecology and the safety of our food supply as related to salmonella.salmonella causes an estimated 1.3 million human foodborne illnesses and more than 500 deaths each year in the united states, representing an annual estimated cost to the economy of approximately $2.4 billion. salmonella enterica comprises more than 2,500 serotypes. with this genetic and environmental diversity, serotypes are adapted to live in a variety of hosts, which may or may not manifest with clinical illness. thus, salmonella presents a multifaceted threat to food production and safety. s ...200817878279
bacteriocin-like inhibitory substances from campylobacter spp.twenty-five campylobacter isolates were screened for production of antimicrobial substances using a deferred antagonism assay. sixteen isolates showed activity against either staphylococcus aureus, salmonella enterica serovar enteritidis or candida albicans. the inhibitory activity was sensitive to treatment with pronase e, trypsin and pepsin, suggesting that the antimicrobial compound(s) are proteinaceous. activity spectra of isolates included s. aureus, micrococcus luteus, streptococcus sp., b ...200817955339
salmonella in healthy pigs: prevalence, serotype diversity and antimicrobial resistance observed during 1998-1999 and 2004-2005 in japan.to determine prevalence, serotype diversity and antimicrobial resistance of salmonella in healthy pigs, faecal samples from 6771 pigs on 73 farms collected during 1998-1999 and 2004-2005 were examined. salmonella isolates were serotyped and tested for susceptibility to 22 antimicrobials: benzylpenicillin, ampicillin, amoxicillin, cefazolin, cephaloridine, gentamicin, kanamycin, streptomycin, fradiomycin, colistin, tetracycline, chlortetracycline, oxytetracycline, chloramphenicol, thiamphenicol, ...200817961277
comparison of salmonella enterica subspecies enterica serovar typhimurium isolates from dairy cattle and humans using in vitro assays of virulence.salmonella enterica subspecies enterica serovar typhimurium (salmonella typhimurium) can infect and cause disease in a wide range of host species however there have been suggestions that this serovar may have genes involved with host range or specificity [tsolis, r.m., townsend, s.m., miao, e.a., miller, s.i., ficht, t.a., adams, l.g., baumler, a.j., 1999. identification of a putative s. enterica serotype typhimurium host range factor with homology to ipah and yopm by signature-tagged mutagenesi ...200817964087
functional characterization of chicken tlr5 reveals species-specific recognition of flagellin.mammalian toll-like receptor 5 (tlr5) senses flagellin of several bacterial species and activates the innate immune system. the avian tlr repertoire exhibits considerable functional diversity compared to mammalian tlrs and evidence of a functional tlr5 in the avian species is lacking. in the present study we cloned and successfully expressed chicken tlr5 (chtlr5) in hela cells, as indicated by laser confocal microscopy. infection of chtlr5 transfected cells with salmonella enterica serovar enter ...200817964652
oral vaccination with salmonella enterica as a cruzipain-dna delivery system confers protective immunity against trypanosoma cruzi.to stimulate both local and systemic immune responses against trypanosoma cruzi, salmonella enterica serovar typhimurium aroa was exploited as a dna delivery system for cruzipain (scz). in a murine model we compared scz alone (gi) or coadministered with salmonella carrying a plasmid encoding granulocyte-macrophage colony-stimulating factor (gii), as well as protocols in which scz priming was followed by boosting with recombinant cruzipain (rcz) admixed with either cpg-odn (giii) or malp-2, a syn ...200817967857
host transmission of salmonella enterica serovar typhimurium is controlled by virulence factors and indigenous intestinal microbiota.transmission is an essential stage of a pathogen's life cycle and remains poorly understood. we describe here a model in which persistently infected 129x1/svj mice provide a natural model of salmonella enterica serovar typhimurium transmission. in this model only a subset of the infected mice, termed supershedders, shed high levels (>10(8) cfu/g) of salmonella serovar typhimurium in their feces and, as a result, rapidly transmit infection. while most salmonella serovar typhimurium-infected mice ...200817967858
antimicrobial resistance genes associated with salmonella enterica serovar newport isolates from food animals.salmonella enterica serotype newport is an important cause of salmonellosis, with strains increasingly being resistant to multiple antimicrobial agents. the increase is associated with the acquisition of multiple resistance genes. this study characterizes the genetic basis of resistance of serotype newport isolates collected from veterinary sources by pcr and dna sequencing analysis.200817967918
a conserved toll-like receptor is required for caenorhabditis elegans innate immunity.pathogen recognition through toll-like receptors (tlrs) is crucial in order to mount an appropriate immune response against microorganisms. on the basis of a lack of evidence indicating that caenorhabditis elegans uses tlrs to elicit an immune response and on the absence of genes encoding rel-like transcription factors in its genome, it is believed that tlr-mediated immunity arose after coelomates split from pseudocoelomates and acoelomates. here, we show that c. elegans tol-1(nr2033) mutants ar ...200817975555
the leucine-responsive regulatory protein, lrp, activates transcription of the fim operon in salmonella enterica serovar typhimurium via the fimz regulatory gene.the fim operon of salmonella enterica serovar typhimurium encodes type 1 fimbriae. the expression of fim is controlled in response to environmental signals through a complex regulatory cascade involving the proteins fimw, fimy, and fimz and a genetic locus, fimu, that encodes a rare arginine trna. we discovered that a knockout mutation in lrp, the gene that codes for the leucine-responsive regulatory protein (lrp), inhibited fim transcription. the loss of fim gene expression was accompanied by a ...200817981960
one pathway can incorporate either adenine or dimethylbenzimidazole as an alpha-axial ligand of b12 cofactors in salmonella enterica.corrinoid (vitamin b12-like) cofactors contain various alpha-axial ligands, including 5,6-dimethylbenzimidazole (dmb) or adenine. the bacterium salmonella enterica produces the corrin ring only under anaerobic conditions, but it can form "complete" corrinoids aerobically by importing an "incomplete" corrinoid, such as cobinamide (cbi), and adding appropriate alpha- and beta-axial ligands. under aerobic conditions, s. enterica performs the corrinoid-dependent degradation of ethanolamine if given ...200817981976
evidence of lethal and sublethal injury in food-borne bacterial pathogens exposed to high-intensity pulsed-plasma gas discharges.to apply scanning electron microscopy, image analysis and a fluorescent viability stain to assess lethal and sublethal injury in food-borne bacteria exposed to pulsed-plasma gas discharges (ppgd).200817983430
prevalence and characterization of salmonella enterica serovar weltevreden from imported seafood.during 2001-2005, 210 salmonella enterica strains were isolated from seafood samples imported into us. strains of s. enterica serovar weltevreden were the most predominantly found among the 64 different serovars isolated. a total of 37 salmonella weltevreden isolates were characterized by pulsed-field gel electrophoresis (pfge), plasmid profiles and antibiotic susceptibility to assess genetic diversity. our results showed a low frequency of antibiotic resistance; 35 of the 37 isolates were sensi ...200817993374
fur regulates expression of the salmonella pathogenicity island 1 type iii secretion system through hild.the invasion of intestinal epithelial cells by salmonella enterica serovar typhimurium is mediated by a type iii secretion system (t3ss) encoded on salmonella pathogenicity island 1 (spi1). expression of the spi1 t3ss is tightly regulated by the combined action of hilc, hild, and rtsa, three arac family members that can independently activate hila, which encodes the direct regulator of the spi1 structural genes. expression of hilc, hild, and rtsa is controlled by a number of regulators that resp ...200817993530
salmonella infection of afferent lymph dendritic cells.the interactions of salmonella enterica subspecies i serotype abortusovis (s. abortusovis) with ovine afferent lymph dendritic cells (aldcs) were investigated for their ability to deliver maedi visna virus (mvv) gag p25 antigens to aldcs purified from afferent lymph. salmonellae were found to enter aldc populations by a process of cell invasion, as confirmed by electron and confocal microscopy. this led to phenotypical changes in aldc populations, as defined by cd1b and cd14 expression. no diffe ...200817986631
the role of roof rats ( rattus rattus) in the spread of salmonella enteritidis and s. infantis contamination in layer farms in eastern japan.the prevalence of salmonella in four layer farms in eastern japan was investigated between 2004 and 2006 to determine the role of roof rats (rattus rattus) in the epizootology of salmonella enterica subsp. enterica serovar enteritidis (s. enteritidis). persistent s. enteritidis and s. infantis contamination of the environment and pooled egg samples were detected in three out of four layer farms. a total of 113 (13.3%) and 158 (18.6%) out of 851 rats examined were positive for s. enteritidis and ...200817988423
effect of fixed or changing temperatures during prolonged storage on the growth of salmonella enterica serovar enteritidis inoculated artificially into shell eggs.the fate of salmonella enterica serovar enteritidis (se) in whole, unbroken eggs was monitored during storage at fixed or changing temperatures after inoculation with 20-47 c.f.u. of se. eggs stored at 10 degrees c and 20 degrees c showed little or no bacterial growth over 6 weeks, while egg storage at 30 degrees c increased the percentage of the eggs that contained >10(6) c.f.u. after 3 weeks. egg storage at 20 degrees c for 5 days followed by 10 degrees c caused only a few eggs with >10(6) c.f ...200817988424
salmonella choleraesuis as an anticancer agent in a syngeneic model of orthotopic hepatocellular carcinoma.some anaerobic and facultative anaerobic bacteria represent novel therapeutic agents that have been recently applied in cancer therapy. previously, we found that salmonella choleraesuis in combination with cisplatin could retard tumor growth in the murine subsutaneous hepatocellular carcinoma (hcc) model. in this regard, we investigated the antitumor activity of s. choleraesuis in the ml-1 orthotopic tumor model. systemically administered s. choleraesuis accumulated within not only subcutaneous ...200817960612
the role of the qsec quorum-sensing sensor kinase in colonization and norepinephrine-enhanced motility of salmonella enterica serovar typhimurium.transcriptional analysis of salmonella enterica serovar typhimurium (s. typhimurium) in the presence of the mammalian hormone norepinephrine revealed up-regulation of genes in the flagellar and chemotaxis regulon. motility assays confirmed enhanced motility of wild-type s. typhimurium in the presence of norepinephrine that could be blocked by the alpha-adrenergic antagonist, phentolamine. furthermore, a mutation in the qsec gene, encoding the sensor kinase of the two-component qsebc quorum-sensi ...200817997077
immunological responses against salmonella enterica serovar typhimurium braun lipoprotein and lipid a mutant strains in swiss-webster mice: potential use as live-attenuated vaccines.we generated and characterized salmonella enterica serovar typhimurium mutants that were deleted for the genes encoding braun lipoprotein (lpp) alone or in conjunction with the msbb gene, which codes for an enzyme required for the acylation of the lipid a moiety of lipopolysaccharide. two copies of the lpp gene, designated as lppa and lppb, exist on the chromosome of s. typhimurium. these mutants were highly attenuated in a mouse infection model and induced minimal histopathological changes in m ...200817997275
fitness and dissemination of disinfectant-selected multiple-antibiotic-resistant (mar) strains of salmonella enterica serovar typhimurium in chickens.the aims of this study were to determine whether strains of salmonella enterica serovar typhimurium which had acquired low-level multiple antibiotic resistance (mar) through repeated exposure to farm disinfectants were able to colonize and transmit between chicks as easily as the parent strain and, if such strains were less susceptible to fluoroquinolones, would high-level resistance be selected after fluoroquinolone treatment.200817999979
emerging trends in enteric fever in nepal: 9124 cases confirmed by blood culture 1993-2003.this was a retrospective study in an urban hospital in kathmandu, nepal to determine the changing burden of salmonella septicaemia, the proportion of salmonella paratyphi a, and the emergence of drug-resistant organisms. the participants were outpatients and inpatients over the period 1993-2003, and the main outcome measures were blood culture isolates and antibiotic sensitivity testing. the results showed that of 82467 blood cultures performed, a bacterium was isolated from 12252. salmonella ac ...200818023462
cloning, expression and characterization of heat shock protein 60 (groel) of salmonella enterica serovar typhi and its role in protective immunity against lethal salmonella infection in mice.heat shock proteins (hsps) represent dominant antigens in numerous microbial infections, suggesting a potential use of pathogen-derived hsps for vaccination. the present study evaluates the immunogenicity and protective efficacy of groel (hsp60) of salmonella enterica serovar typhi against lethal challenge by s. typhi ty2 and salmonella enterica serovar typhimurium in mice. the groel gene was cloned and expressed in escherichia coli bl21 and purified by affinity chromatography. immunization of m ...200818024219
luxs affects flagellar phase variation independently of quorum sensing in salmonella enterica serovar typhimurium.luxs catalyzes the synthesis of the quorum-sensing signaling molecule autoinducer 2. we show that in salmonella enterica serovar typhimurium, deletion of the luxs gene polarizes flagellar phase variation toward the more immunogenic phase 1 flagellin. this phenotype is complementable by luxs in trans but is independent of quorum-sensing signals.200818024511
salmonella enterica burden in harvest-ready cattle populations from the southern high plains of the united states.our objectives were to quantify the salmonella enterica burdens in harvest-ready cattle and to identify specific at-risk populations of cattle most likely to harbor multiply resistant s. enterica. hide swabs were collected in abattoirs from three cohorts of cattle (feedlot origin cattle that had achieved desirable harvest characteristics and dairy- and beef-type cows harvested because of poor productivity). feces were collected from two cohorts housed in feedlots (cattle that had achieved desira ...200818024678
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