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large-scale identification of essential salmonella genes by trapping lethal insertions.a novel screening approach based on insertion-duplication mutagenesis (idm) was established to efficiently screen for essential genes of salmonella enterica serovar typhimurium under laboratory conditions. small, randomly generated genomic fragments were cloned into a conditionally replicating vector, and the resulting library of single salmonella clones was grown under permissive conditions. upon switching to non-permissive temperature, discrimination between lethal and non-lethal insertions fo ...200415009898
post-transcriptional regulation of bacterial motility by aconitase proteins.escherichia coli and bacillus subtilis aconitases can act as iron and oxidative stress-responsive post-transcriptional regulators. here, it is shown that a salmonella enterica serovar typhimurium lt2 acnb mutant exhibits impaired binding to the surface of j774 macrophage-like cells. proteomic analyses were used to investigate further the binding defect of the acnb mutant. these revealed that the levels of the flagellum protein flic were much lower for the acnb mutant. this strain was correspondi ...200415009904
live salmonella enterica serovar typhimurium (s. typhimurium) elicit dendritic cell responses that differ from those induced by killed s. typhimurium.the immune response of bovine monocytes-derived dendritic cells (dc) exposed to either live or killed salmonella enterica serovar typhimurium was compared. both live and killed bacteria induced changes in morphology with distinctive formation of processes and up-regulation of the ability of dc to stimulate allogeneic t-cell proliferation. also, both live and killed bacteria up-regulated the expression of mhc-i, mhc-ii and cd80. however, live bacteria induced greater up-regulation of the expressi ...200415010228
anti-salmonella activity of (2e)-alkenals.this study investigated the effect of a series of naturally occurring aliphatic (2e)-alkenals against salmonella choleraesuis subsp. choleraesuis atcc 35640 and evaluated their antibacterial action.200415012807
isolation of salmonella strains from reptile faeces and comparison of different culture media.to provide information on epidemiology and isolation of salmonella strains from reptiles.200415012809
comparison of 40 salmonella enterica serovars injured by thermal, high-pressure and irradiation stress.to investigate and compare the inherent resistance of 40 salmonella serovars to heat, irradiation and high-pressure stress.200415012829
dietary fructo-oligosaccharides and inulin decrease resistance of rats to salmonella: protective role of calcium.we have shown recently that rapid fermentable fructo-oligosaccharides (fos) decreased resistance of rats towards salmonella. it is not known whether inulin (which is fermented more gradually) has similar effects or whether buffering nutrients can counteract the adverse effects of rapid fermentation.200415016747
pulsed-field gel electrophoresis-based subtyping of dna degradation-sensitive salmonella enterica subsp. enterica serovar livingstone and serovar cerro isolates obtained from a chicken layer farm.salmonella enterica serovar subsp. enterica livingstone and serovar cerro isolates from a commercial egg-producing farm, which had previously been untypeable by pulsed-field gel electrophoresis (pfge) because of dna degradation during the pfge process, successfully gave banding patterns using electrophoresis buffer supplemented with 50 microm thiourea. by pfge in the presence of thiourea, dna degradation-sensitive s. enterica serovar cerro isolates from the commercial egg-producing farm were fou ...200415019105
activity of dermaseptin k4-s4 against foodborne pathogens.dermaseptin s4 and its substituted derivative k(4)-s4 were investigated against various food-related pathogenic bacteria in culture media. k(4)-s4, but not the native peptide displayed significant growth inhibitory activity against all bacteria tested. next, activity of k(4)-s4 against escherichia coli o157:h7 was defined in terms of milieu dependencies. salt-dependent kinetic studies in growth medium indicated that the peptide's antibacterial activity is maintained at fairly high (up to 600mm) ...200315019214
outbreak of neonatal meningitis caused by salmonella enterica serotype worthington.we report an outbreak of salmonella meningitis in a nursery unit due to serotype worthington. the organism was isolated from blood and csf samples of five babies. the isolates were found to be resistant to commonly used antibiotics such as ampicillin, cefotaxime, cefiriaxone and amikacin but were sensitive to ciprofloxacin. serotype worthington appears to be an emerging pathogen in neonatal units.200315022937
detection of o-acetylated vi polysaccharide of salmonella enterica subspecies typhi by enzyme immunoassay.immunisation with capsular vi polysaccharide (vi ps) of salmonella enterica serovar typhi (s. typhi) protects against typhoid. this protection depends on the presence of o-acetyl groups on the vi ps, which form an immunodominant epitope. an antiserum raised against conjugated vi ps was used as the basis for an indirect enzyme immunoassay (eia). the antiserum did not react with lipopolysaccharide of five gram negative bacteria including s. typhi. vi ps from three different sources was tested, and ...200415026021
complete genomic sequence of the virulent salmonella bacteriophage sp6.we report the complete genome sequence of enterobacteriophage sp6, which infects salmonella enterica serovar typhimurium. the genome contains 43,769 bp, including a 174-bp direct terminal repeat. the gene content and organization clearly place sp6 in the coliphage t7 group of phages, but there is approximately 5 kb at the right end of the genome that is not present in other members of the group, and the homologues of t7 genes 1.3 through 3 appear to have undergone an unusual reorganization. sequ ...200415028677
the spectrum of cardiovascular infections due to salmonella enterica: a review of clinical features and factors determining outcome.cardiovascular infections due to salmonella enterica are infrequently reported, so their clinical features, prognosis, and optimal treatment are not completely known. mortality associated with aortitis and endocarditis caused by nontyphoidal salmonella remains exceedingly high. in this review of cases of cardiovascular infections due to salmonella enterica studied in 2 hospitals in madrid, we tried to assess the clinical manifestations and the procedures leading to diagnosis in addition to treat ...200415028966
prevalence and characteristics of shiga toxin-producing escherichia coli, salmonella spp. and campylobacter spp. isolated from slaughtered sheep in switzerland.caecum samples collected from 653 slaughtered sheep from two swiss abattoirs were examined. the aim of this study was: (i) to determine the prevalence of shiga toxin-producing escherichia coli (stec), salmonella spp. and campylobacter spp.; (ii) to further characterize isolated strains; and (iii) to discuss the results obtained with their relevance to food safety. the percentage of samples testing positive for stec by a polymerase chain reaction was 29.9%. the prevalence of positive salmonella s ...200415033267
short-course azithromycin for the treatment of uncomplicated typhoid fever in children and adolescents.we studied 149 children and adolescents 3-17 years of age with clinical typhoid fever who were treated with either oral azithromycin (20 mg/kg per day; maximum dose, 1000 mg/day) or intravenous ceftriaxone (75 mg/day; maximum dose, 2.5 g/day) daily for 5 days. blood and stool specimens were obtained for culture before the initiation of therapy and were repeated on days 4 and 8 of treatment. isolation of salmonella enterica serovar typhi or s. enterica serovar paratyphi from the initial culture w ...200415034826
quantitative oligonucleotide microarray fingerprinting of salmonella enterica isolates.we report on a genome-independent microbial fingerprinting method using nucleic acid microarrays for microbial forensics and epidemiology applications and demonstrate that the microarray method provides high resolution differentiation between closely related microorganisms, using salmonella enterica strains as the test case. in replicate trials we used a simple 192 probe nonamer array to construct a fingerprint library of 25 closely related salmonella isolates. controlling false discovery rate f ...200415037662
the probiotic escherichia coli strain nissle 1917 interferes with invasion of human intestinal epithelial cells by different enteroinvasive bacterial pathogens.the probiotic escherichia coli strain nissle 1917 (mutaflor) of serotype o6:k5:h1 was reported to protect gnotobiotic piglets from infection with salmonella enterica serovar typhimurium. an important virulence property of salmonella is invasion of host epithelial cells. therefore, we tested for interference of e. coli strain nissle 1917 with salmonella invasion of int407 cells. simultaneous administration of e. coli strain nissle 1917 and salmonella resulted in up to 70% reduction of salmonella ...200415039098
lon protease activity causes down-regulation of salmonella pathogenicity island 1 invasion gene expression after infection of epithelial cells.salmonella enterica serovar typhimurium causes self-limiting gastroenteritis in humans and a typhoid-like disease in mice that serves as a model for typhoid infections in humans. a critical step in salmonella pathogenesis is the invasion of enterocytes and m cells of the small intestine via expression of a type iii secretion system, encoded on salmonella pathogenicity island 1 (spi-1), that secretes effector proteins into host cells, leading to engulfment of the bacteria within large membrane ru ...200415039320
rapid expression of chemokines and proinflammatory cytokines in newly hatched chickens infected with salmonella enterica serovar typhimurium.poultry meat and eggs contaminated with salmonella enterica serovar enteritidis or salmonella enterica serovar typhimurium are common sources of acute gastroenteritis in humans. however, the exact nature of the immune mechanisms protective against salmonella infection in chickens has not been characterized at the molecular level. in the present study, bacterial colonization, development of pathological lesions, and proinflammatory cytokine and chemokine gene expression were investigated in the l ...200415039338
salmonella flagellin is not a dominant protective antigen in oral immunization with attenuated live vaccine strains.we found that oral immunization with flagellum-defective mutant strains of salmonella enterica serovar typhimurium with the clpxp-deficient background protected mice against oral challenge with the virulent strain. these data indicate that salmonella flagellin is not a dominant protective antigen in oral immunization with attenuated live vaccine strains.200415039380
effect of 2-deoxy-d-glucose induced stress on salmonella choleraesuis shedding and persistence in swine.a glucose analog, 2-deoxy-d-glucose (2dg), previously shown in swine to induce many of the hallmark parameters of stress, was administered to salmonella choleraesuis carrier-swine and the effects on salmonella fecal shedding and tissue colonization were evaluated. initially, pigs were divided into two groups, one that received 1 x 10 (6) s. choleraesuis and one group that received saline. at 3 or 6 weeks post inoculation (pi), half of each group received an injection of 2dg and the other half re ...200415046951
expression of acrb, acrf, acrd, mara, and soxs in salmonella enterica serovar typhimurium: role in multiple antibiotic resistance.comparative reverse transcription-pcr in combination with denaturing high-pressure liquid chromatography analysis was used to determine the levels of expression of soxs, mara, acrf, acrb, and acrd in multiple-antibiotic-resistant (mar) salmonella enterica serovar typhimurium isolates and mutants of s. enterica serovar typhimurium sl1344 with defined deletions. posttherapy mar clinical isolates had increased levels of expression of all genes except soxs. s. enterica serovar typhimurium sl1344 del ...200415047514
evidence for a chromosomally located third integron in salmonella enterica serovar typhimurium dt104b.salmonella enterica serovar typhimurium isolates of phage types dt104 and dt104b are frequently associated with multiple antimicrobial resistance. we describe the characterization of a class 1 integron containing dfra1 and aada1, genes from two salmonella serovar typhimurium dt104b isolates. genetic mapping located the integron to the bacterial chromosome in each case.200415047541
protection from bacterial infection by a single vaccination with replication-deficient mutant herpes simplex virus type 1.adaptive immune responses in which cd8(+) t cells recognize pathogen-derived peptides in the context of major histocompatibility complex class i molecules play a major role in the host defense against infection with intracellular pathogens. cells infected with intracellular bacteria such as listeria monocytogenes, salmonella enterica serovar typhimurium, or mycobacterium tuberculosis are directly lysed by cytotoxic cd8(+) t cells. for this reason, current vaccines for intracellular pathogens, su ...200415047818
tubular glands of the isthmus are the predominant colonization site of salmonella enteritidis in the upper oviduct of laying hens.salmonella enterica serovar enteritidis is the serovar most frequently isolated from chicken eggs. colonization of the upper oviduct of hens is believed to play an important role in egg contamination. the interaction of s. enteritidis with gland epithelial cells of the isthmus and the magnum was, therefore, studied in vitro and in vivo. in the first experiment, s. enteritidis bacteria were added to confluent monolayers of primary cultures of chicken tubular epithelial cells of the isthmus (ictec ...200415049486
salmonella enterica subsp. enterica serovar enteritidis harbours cole1, cole2, and rolling-circle-like replicating plasmids.using dna hybridization, at least three distinct groups of low molecular mass plasmids were identified in salmonella enterica subsp. enterica serovar enteritidis. after sequencing representative plasmids from each group, we concluded that they belonged to cole1, cole2, and rolling-circle-like replicating plasmids. plasmid pk (4245 bp) is a representative of widely distributed cole1 plasmids. plasmid pp (4301 bp) is homologous to cole2 plasmids and was present predominantly in single-stranded dna ...200415052312
[quinolone use and resistance]. 200415056434
[resistance to quinolones and beta-lactams in salmonella enterica due to mutations in topoisomerase-encoding genes, altered cell permeability and expression of an active efflux system].the mechanisms of resistance to fluoroquinolones and beta-lactams were studied in isolates of salmonella enterica resistant to both antimicrobial groups, isolated over time from two patients treated with fluoroquinolones.200415056435
[mechanisms of resistance to beta lactams and nalidixic acid in clinical isolates of salmonella enteritidis serotype hadar and bsilla]. 200415056446
characterization of six flagellin genes in the h3, h53 and h54 standard strains of escherichia coli.six flagellin genes in three h standard escherichia coli strains for h3, h53 and h54 were characterized. each strain has two flagellin genes, one of which is expressed as its standard h antigen. a pair of flagellin genes flka3 (encoding for h3 antigen) and flic16 (h16) was cloned from bi7327-41, flka53 (h53) and flic-53 from e480-68, and flma54 (h54) and flic-54 from e223-69. two flic genes, flic-53 and flic-54, are nonfunctional owing to the insertions of is1 and is1222, respectively. the flka ...200415056931
genetic analysis of the salmonella enterica type iii secretion-associated atpase invc defines discrete functional domains.an essential component of all type iii secretion systems is a highly conserved atpase that shares significant amino acid sequence similarity to the beta subunit of the f(0)f(1) atpases and is thought to provide the energy for the secretion process. we have performed a genetic and functional analysis of invc, the atpase associated with the salmonella enterica type iii secretion system encoded within its pathogenicity island 1. through a mutagenesis analysis, we have identified amino acid residues ...200415060043
phop can activate its target genes in a phoq-independent manner.the phop/phoq two-component system controls the extracellular magnesium depletion response in salmonella enterica. previous studies have shown that phop is unable to up-regulate its target genes in the absence of phoq function. in this work, we demonstrate that phop overexpression can substitute for phoq- and phosphorylation-dependent activation. either a high concentration of phop or activation via phosphorylation stimulates phop self-association.200415060051
bacteria-host interactions of salmonella paratyphi b dt+ in poultry.in recent years, a dramatic increase in incidence of the dextro-rotatory tartrate-positive variant (dt+) of salmonella enterica subspecies enterica serovar paratyphi b has been observed in poultry and poultry products. in the present study the interactions of this bacterium with the host were studied in vivo and in vitro in an attempt to explain the preferential association of this serotype with poultry. the ability of this organism to invade and multiply in chicken intestinal epithelial cells a ...200415061498
antibiotic resistance in salmonella enterica serotypes typhimurium, enteritidis and infantis from human infections, foodstuffs and farm animals in italy.the antimicrobial susceptibility of isolates of salmonella enterica serotypes typhimurium, enteritidis, and infantis isolated from humans, foodstuffs and farm animals in italy between 1999 and 2001 was examined. all the isolates were susceptible to cefotaxime and ciprofloxacin, but high rates of resistance were observed for several other drugs, especially for s. typhimurium. the rates of resistance and multiresistance were generally higher among animal and food isolates than in human strains; co ...200415061499
molecular epidemiology and population genetics of salmonella subspecies diarizonae in sheep in norway and sweden.fifty-four isolates of salmonella enterica subsp. diarizonae (iiib) in norway, sweden, england, the united states, france and australia were characterized by pulsed-field gel electrophoresis (pfge). this study focuses on serovar 61:k:1,5,(7) [s. iiib 61:k:1,5,(7)] isolated from sheep. digestion of the bacterial dna with restriction enzyme xhai yielded 15 distinct pfge profiles comprising 12-16 fragments in the range 48.5-630.5 kbp. four different profiles were identified in norwegian sheep isola ...200415061500
molecular characterization of salmonella enterica subsp. enterica serovar typhimurium dt1 isolates.salmonella typhimurium dt1 is endemic to finland and has caused human outbreaks since the 1960s. domestic dt1 isolates (n=235) from 1972 to 1999 from human cases, animals and other sources, as well as foreign dt1 isolates from human cases (n=20) were analysed by molecular methods. pulsed-field gel electrophoresis (pfge) yielded 38 xbai profiles. of these, xbai profile 10 was seen in 49% (125/255) of the isolates. twelve is200 profiles were obtained; the most common is200 profile d was seen in 64 ...200415061501
salmonella enterica serotype javiana infections associated with amphibian contact, mississippi, 2001.salmonella javiana is a salmonella serotype that is restricted geographically in the united states to the southeast. during the summer of 2001, the number of reported s. javiana infections in mississippi increased sevenfold. to identify sources of infection, we conducted a case-control study, defining a case as an infection with s. javiana between august and september in a mississippi resident. we enrolled 55 cases and 109 controls. thirty (55%) case patients reported exposure to amphibians, def ...200415061502
plasmid-mediated florfenicol and ceftriaxone resistance encoded by the flor and bla(cmy-2) genes in salmonella enterica serovars typhimurium and newport isolated in the united states.multidrug resistance plasmids carrying the bla(cmy-2) gene have been identified in salmonella enterica serovars typhimurium and newport from the united states. this gene confers decreased susceptibility to ceftriaxone, and is most often found in strains with concomitant resistance to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole and tetracycline. the bla(cmy-2)-carrying plasmids studied here were shown to also carry the florfenicol resistance gene, flor, on a genetic structure prev ...200415063500
oral immunization of chickens with avirulent salmonella vaccine strain carrying c. jejuni 72dz/92 cjaa gene elicits specific humoral immune response associated with protection against challenge with wild-type campylobacter.it is well documented that poultry and poultry products are the major source of human campylobacteriosis and salmonellosis. this study examined the general efficacy of avirulent salmonella vaccine strains expressing campylobacter antigen as a bivalent chicken vaccine prototype. three c. jejuni genes: cjaa (cj0982c), cjac (cj0734c) and cjad (cj0113) encoding highly immunogenic proteins which are conserved among different campylobacter serotypes, were introduced into avirulent salmonella enterica ...200415063560
a link between transcription and intermediary metabolism: a role for sir2 in the control of acetyl-coenzyme a synthetase.the silent information regulator protein (sir2) and its homologs (collectively known as sirtuins) are nad+-dependent deacetylase enzymes involved in chromosome stability, gene silencing and cell aging in eukaryotes and archaea. the discovery that sirtuin-dependent protein deacetylation is a nad+-consuming reaction established a link with the energy generation systems of the cell. this link to metabolism was recently extended to the post-translational control of the activity of short-chain fatty ...200415063846
the shda adhesin binds to the cationic cradle of the fibronectin 13fniii repeat module: evidence for molecular mimicry of heparin binding.introduction of salmonella enterica serotype typhimurium into food products results from its ability to persist in the intestine of healthy livestock by mechanisms that are poorly understood. the non-fimbrial adhesin shda is a fibronectin binding protein required for persistent intestinal carriage of s. typhimurium. we further investigated the molecular mechanism of shda-mediated intestinal persistence by determining the binding-site of this receptor in fibronectin. analysis of shda binding to f ...200415066025
health hazards posed by feral pigeons.a comprehensive literature search of epidemiological studies and reports of transmissions of disease from feral pigeons to humans was performed. there were 176 documented transmissions of illness from feral pigeons to humans reported between 1941 and 2003. feral pigeons harbored 60 different human pathogenic organisms, but only seven were transmitted to humans. aerosol transmission accounted for 99.4% of incidents. there was a single report of transmission of salmonella enterica serotype kiambu ...200415066331
effect of acidified feed on susceptibility of broiler chickens to intestinal infection by campylobacter and salmonella.consumption of poultry meat is associated with human campylobacter and salmonella infections. one way to control the presence of these bacteria in broiler flocks is to make chickens less susceptible for colonisation. acidification of feed may be a tool to reduce the campylobacter and salmonella carriage in broiler chickens. in the present experiments an acidified feed with high levels of organic acid, 5.7% lactic acid and 0.7% acetic acid, was applied. in an in vitro experiment the reduction or ...200415066728
influence of environmental factors and human activity on the presence of salmonella serovars in a marine environment.the temporal and spatial distribution of salmonella contamination in the coastal waters of galicia (northwestern spain) relative to contamination events with different environmental factors (temperature, wind, hours of sunlight, rainfall, and river flow) were investigated over a 4-year period. salmonellae were isolated from 127 of 5,384 samples of molluscs and seawater (2.4%), and no significant differences (p < 0.05) between isolates obtained in different years were observed. the incidence of s ...200415066800
fate of salmonella enterica serovar typhimurium on carrots and radishes grown in fields treated with contaminated manure composts or irrigation water.three different types of compost, pm-5 (poultry manure compost), 338 (dairy cattle manure compost), and nviro-4 (alkaline-ph-stabilized dairy cattle manure compost), and irrigation water were inoculated with an avirulent strain of salmonella enterica serovar typhimurium at 10(7) cfu g(-1) and 10(5) cfu ml(-1), respectively, to determine the persistence of salmonellae in soils containing these composts, in irrigation water, and also on carrots and radishes grown in these contaminated soils. a spl ...200415066849
adaptive acid tolerance response in salmonella enterica serovar typhimurium and salmonella enterica serovar typhi.the survival of bacteria in various environments depends on a number of protective responses including acid tolerance response (atr). in this study, atr phenomenon was compared in salmonella enterica serovar typhi 6 and salmonella enterica serovar typhimurium 98 under different culture conditions. survival of the adapted culture (pre-acid shocked to ph 5.5) was significantly better (p < 0.05) as compared to control, unadapted culture after acid shock at ph 3.3. however, the atr varied with the s ...200415069673
salmonella typhi encodes a functional cytolethal distending toxin that is delivered into host cells by a bacterial-internalization pathway.many bacterial pathogens encode the cytolethal distending toxin (cdt), which causes host cells to arrest during their cell cycle by inflicting dna damage. cdt is composed of three proteins, cdta, cdtb, and cdtc. cdtb is the enzymatically active or a subunit, which possesses dnase i-like activity, whereas cdta and cdtc function as heteromeric b subunits that mediate the delivery of cdtb into host cells. we show here that salmonella enterica serovar typhi encodes cdt activity, which depends on the ...200415070766
characterization of multidrug-resistant typhoid outbreaks in kenya.we characterized by antibiotic susceptibility, plasmid analysis, incompatibility grouping, and pulsed-field gel electrophoresis (pfge) of xbai- and spei-digested dna 102 salmonella enterica serovar typhi (serovar typhi) isolated from recent outbreaks of typhoid in three different parts of kenya. only 13.7% were fully susceptible, whereas another 82.4% were resistant to each of the five commonly available drugs: ampicillin, chloramphenicol, and tetracycline (mics of >256 microg/ml); streptomycin ...200415070992
development of a multiplex pcr technique for detection and epidemiological typing of salmonella in human clinical samples.we have developed a multiplex pcr assay for salmonella detection and epidemiological typing. six sets of primers were designed to detect the major salmonella serotypes and phage types in spain. an internal amplification control was designed in order to detect pcr inhibition. the different amplification profiles obtained allowed us to detect salmonella bacteria and to distinguish the clinically prevalent salmonella enterica serotypes enteritidis, typhimurium and subspecies i serotype 4,5,12:i:-. ...200415071035
molecular characterization of a prophage of salmonella enterica serotype typhimurium dt104.isolates of the salmonella enterica serotype typhimurium definitive phage type (dt104) were found to contain the same prophage (designated phage st104). the complete sequence of the dna genome of prophage st104 was determined. the entire dna sequence consisted of 41,391 bp, including 64 open reading frames, and exhibited high similarity to p22 and to phage type conversion phage st64t.200415071057
flagella and curli fimbriae are important for the growth of salmonella enterica serovars in hen eggs.salmonella enterica serovar enteritidis is unable to multiply in the albumen of fresh eggs and must gain access to the yolk contents in order to multiply to a high level (>10(6) c.f.u. per ml egg contents). as human salmonella infections resulting from the consumption of infected eggs more frequently involve serovar enteritidis phage type (pt) 4 than other serovars or pts, a number of isolates of various s. enterica serovars were examined for their ability to multiply to a high level in eggs ove ...200415073315
effect of drinking-water administration of experimental chlorate ion preparations on salmonella enterica serovar typhimurium colonization in weaned and finished pigs.foodborne disease caused by salmonella is of public health and economic significance. in order to assess the practical effectiveness of a new intervention strategy, experimental chlorate preparations (ecp) were administered via the drinking water to weaned and finished pigs that had been orally challenged the previous day with 10(9)-10(10) colony-forming units of salmonella serovar typhimurium. after 24 or 36 h ad libitum access to 0x, 1x or 2x ecp treatment (where x is the concentration estimat ...200415074764
deciphering the function of an orf: salmonella enterica deom protein is a new mutarotase specific for deoxyribose.we identified in salmonella enterica serovar typhi a cluster of four genes encoding a deoxyribokinase (deok), a putative permease (deop), a repressor (deoq), and an open reading frame encoding a 337 amino acid residues protein of unknown function. we show that the latter protein, called deom, is a hexamer whose synthesis is increased by a factor over 5 after induction with deoxyribose. the cd spectrum of the purified recombinant protein indicated a dominant contribution of betatype secondary str ...200415075407
foodborne outbreaks in northern portugal, 2002.in october 2001, foodborne outbreaks (fbo) were included in the portuguese alert and response surveillance system. accordingly, the northern regional health authority (delegado regional de saude do norte--drsn) began a surveillance programme of foodborne outbreaks. this report is a brief description of data generated from this programme in 2002. for each foodborne outbreak the local health authority (delegado de saude concelhio--dsc) produced a written report. fifty-nine percent of the 27 fbos s ...200415075482
the role of litter beetles as potential reservoir for salmonella enterica and thermophilic campylobacter spp. between broiler flocks.we evaluated the role of beetles infesting broiler chicken rearing facilities as potential reservoirs for salmonella enterica infections between successive broiler flocks. in addition, their role as potential reservoirs for thermophilic campylobacter spp. was also investigated. fourteen broiler houses located at 11 different farms were included in the study. the houses were nonrandomly selected on the basis of their salmonella status; nine were persistently contaminated with salmonella whereas f ...200415077793
effects of prior coinfection with different salmonella serovars on the progression of a salmonella enterica serovar enteritidis infection in hens undergoing induced molt.four trials were conducted to evaluate whether prior infection with salmonella enterica serovar typhimurium (s. typhimurium) or salmonella enterica serovar muenchen (s. muenchen) would modify the severity or the transmission of salmonella enterica serovar enteritidis (s. enteritidis) challenge in hens undergoing molt via feed withdrawal. hens were separated into two groups where one group received a prior s. typhimurium or s. muenchen infection, whereas the other group remained untreated until s ...200415077810
the effect of killed salmonella enteritidis vaccine prior to induced molting on the shedding of s. enteritidis in laying hens.effects of administering killed salmonella enterica serovar enteritidis (se) vaccines to laying hens prior to induced molting on egg production and on shedding of se were investigated. forty hens were vaccinated with one of two se vaccines available commercially in the united states and japan. twenty-five days after vaccination, feed was withdrawn for 2 wk from 20 vaccinated plus 10 unvaccinated hens to induce molt. four days after molt induction, all hens were challenged with a dose of 2.4 x 10 ...200415077813
in vitro activity of nitrofuran derivatives on growth and morphology of salmonella enterica serotype enteritidis.to evaluate the effect of nitrofuran derivatives furazolidone (fz) and nitrofurantoin (nf) on salmonella enterica serovar enteritidis pt4 in vitro, with regard to cell growth, morphology and ultrastructure.200415078517
salmonella enteritidis infections, united states, 1985-1999.salmonella enterica serotype enteritidis emerged as an important illness during the 1980s. investigations showed that consumption of undercooked eggs was the major risk factor for disease, and a variety of prevention and control efforts were initiated during the 1990s. we describe sporadic infections and outbreaks of s. enteritidis in the united states from 1985 through 1999 and discuss prevention and control efforts. after reaching a high of 3.9 per 100,000 population in 1995, s. enteritidis in ...200415078589
ciprofloxacin-resistant salmonella enterica typhimurium and choleraesuis from pigs to humans, taiwan.we evaluated the disk susceptibility data of 671 nontyphoid salmonella isolates collected from different parts of taiwan from march 2001 to august 2001 and 1,261 nontyphoid salmonella isolates from the national taiwan university hospital from 1996 to 2001. overall, ciprofloxacin resistance was found in 2.7% (18/671) of all nontyphoid salmonella isolates, in 1.4% (5/347) of salmonella enterica serotype typhimurium and in 7.5% (8/107) in s. enterica serotype choleraesuis nationwide. mics of six ne ...200415078598
salmonella serovars from humans and other sources in thailand, 1993-2002.we serotyped 44,087 salmonella isolates from humans and 26,148 from other sources from 1993 through 2002. the most common serovar causing human salmonellosis in thailand was salmonella enterica weltevreden. serovars causing human infections in thailand differ from those in other countries and seem to be related to salmonella serovars in different food products and reservoirs.200415078609
evidence against reciprocal recombination as the basis for tuf gene conversion in salmonella enterica serovar typhimurium.the duplicate tuf genes on the salmonella enterica serovar typhimurium chromosome co-evolve by a reca-, recb-dependent gene conversion mechanism. gene conversion is defined as a non-reciprocal transfer of genetic information. however, in a replicating bacterial chromosome there is a possibility that a reciprocal genetic exchange between different tuf genes sitting on sister chromosomes could result in "apparent" gene conversion. we asked whether the major mechanism of tuf gene conversion was cla ...200415081805
reduction of escherichia coli o157:h7 and salmonella enterica serovar enteritidis in chicken manure by larvae of the black soldier fly.green fluorescent protein-labeled escherichia coli o157:h7 and salmonella enterica serovar enteritidis were inoculated at 10(7) cfu/g into cow, hog, or chicken manure. ten- or 11-day-old soldier fly larvae (hermetia illucens l.) (7 to 10 g) were added to the manure and held at 23, 27, or 32 degrees c for 3 to 6 days. soldier fly larvae accelerated inactivation of e. coli o157:h7 in chicken manure but had no effect in cow manure and enhanced survival in hog manure. the initial ph values of the ho ...200415083719
salmonella enterica serovars from pigs on farms and after slaughter and validity of using bacteriologic data to define herd salmonella status.the primary objective of this study was to evaluate the validity of using data obtained from slaughtered pigs for farm-level epidemiologic studies of salmonella. the study involved groups of pigs from five farms. salmonella isolates were obtained from on-farm samples, and a total of 370 on-farm and an additional 486 isolates from samples collected after commercial slaughter were subsequently tested. preharvest samples included feces of individual animals from defined groups of nursery and finish ...200415083720
characterization of antimicrobial-resistant phenotypes and genotypes among salmonella enterica recovered from pigs on farms, from transport trucks, and from pigs after slaughter.the main objectives of this study were to determine antimicrobial resistance patterns among salmonella serotypes and to evaluate the role of transport trucks in dissemination of antimicrobial-resistant strains of salmonella. salmonella from groups of nursery and finishing pigs on farms, from trucks, and from pigs after slaughter were compared using serotyping, patterns of antimicrobial resistance, and pulsed-field gel electrophoresis patterns. the five farms included in the study yielded 858 iso ...200415083721
efficacy of egg cleaning compounds on eggshells contaminated with salmonella enterica serovar enteritidis.salmonella enteritidis infections of egg contents can be related to external contamination of the shell. in this study, the efficacy of three commercial cleaning and/or sanitizing compounds (sodium carbonate, sodium hypochlorite, and potassium hydroxide) was evaluated for bactericidal activity at ph values of 10, 11, and 12 against various concentrations (10(2), 10(4), or 10(6) cfu/ml) of salmonella enteritidis inoculated onto the eggshell surface. efficacy of these chemical agents was also asse ...200415083722
salmonella enterica serotype choleraesuis: epidemiology, pathogenesis, clinical disease, and treatment.nontyphoid salmonella strains are important causes of reportable food-borne infection. among more than 2,000 serotypes, salmonella enterica serotype choleraesuis shows the highest predilection to cause systemic infections in humans. the most feared complication of serotype cholearesuis bacteremia in adults is the development of mycotic aneurysm, which previously was almost uniformally fatal. the advances in diagnostic techniques, surgical care, and antimicrobial therapy have greatly improved the ...200415084503
effector proteins encoded by salmonella pathogenicity island 2 interfere with the microtubule cytoskeleton after translocation into host cells.the facultative intracellular pathogen salmonella enterica has evolved strategies to modify its fate inside host cells. one key virulence factor for the intracellular pathogenesis is the type iii secretion system encoded by salmonella pathogenicity island 2 (spi2). we have previously described spi2-encoded ssef and sseg as effector proteins that are translocated by intracellular salmonella. detailed analysis of the subcellular localization of ssef and sseg within the host cell indicated that the ...200415086785
host restriction of salmonella enterica serotype typhimurium pigeon isolates does not correlate with loss of discrete genes.the definitive phage types (dt) 2 and 99 of salmonella enterica serotype typhimurium are epidemiologically correlated with a host range restricted to pigeons, in contrast to phage types with broader host ranges such as epidemic cattle isolates (dt104 and dt204). to determine whether phage types with broad host range possess genetic islands absent from host-restricted phage types, we compared the genomes of four pigeon isolates to serotype typhimurium strain lt2 using a dna microarray. three of t ...200415090502
highly divergent rfah orthologs from pathogenic proteobacteria can substitute for escherichia coli rfah both in vivo and in vitro.the transcriptional enhancer protein rfah positively regulates production of virulence factors in escherichia coli and salmonella enterica serovar typhimurium via a cis element, ops. genes coding for rfah orthologs were identified in conceptually translated genomes of bacterial pathogens, including vibrio and yersinia spp. we cloned the rfah genes from vibrio cholerae, yersinia enterocolitica, s. enterica serovar typhimurium, and klebsiella pneumoniae into e. coli expression vectors. purified rf ...200415090525
isolation of salmonella enterica serotype choleraesuis resistant to ceftriaxone and ciprofloxacin.salmonella enterica serotype choleraesuis (s choleraesuis) usually causes systemic infections in man that need antimicrobial treatment. we isolated a strain of s choleraesuis that was resistant to ceftriaxone and ciprofloxacin from a patient with sepsis. ciprofloxacin resistance was associated with mutations in gyra and parc, whereas the ampc gene (bla(cmy-2)), responsible for ceftriaxone resistance, was carried by a transposon-like mobile element. this element was found inserted into finq of a ...200415094275
optimization of randomly amplified polymorphic dna-polymerase chain reaction for molecular typing of salmonella enterica serovar typhi.optimization of the rapd reaction for characterizing salmonella enterica serovar typhi strains was studied in order to ensure the reproducibility and the discriminatory power of this technique. eight salmonella serovar typhi strains isolated from various regions in brazil were examined for the fragment patterns produced using different concentrations of dna template, primer, mgcl2 and taq dna polymerase. using two different low stringency thermal cycle profiles, the rapd fingerprints obtained we ...200415094899
prior antimicrobial agent use increases the risk of sporadic infections with multidrug-resistant salmonella enterica serotype typhimurium: a foodnet case-control study, 1996-1997.several strains of multidrug-resistant (mdr) salmonella serotype typhimurium, including mdr s. typhimurium definitive type 104, cause almost 10% of salmonella infections among humans in the united states. to determine the risk factors for acquiring sporadic mdr s. typhimurium infection, we conducted a population-based, case-control study using data from the foodborne diseases active surveillance network (foodnet) during 1996-1997. s. typhimurium isolates from 5 foodnet surveillance areas (califo ...200415095194
chicken consumption is a newly identified risk factor for sporadic salmonella enterica serotype enteritidis infections in the united states: a case-control study in foodnet sites.the sources of sporadic salmonella enterica serotype enteritidis (se) infections in the united states are unclear. to determine risk factors for sporadic se infection, we conducted a population-based case-control study in 5 foodborne disease active surveillance network surveillance areas. during the 12-month study, 396 cases of se infection were ascertained. among the 182 case patients and 345 controls, se infection was univariately associated with international travel (matched odds ratio [mor], ...200415095196
risk factors for salmonella enterica subsp. enterica shedding by market-age pigs in french farrow-to-finish herds.fattening-pigs carriers of salmonella enterica are believed to be a main source of carcass and pork contamination at the later steps of the meat process. we did a prospective study in 2000-2001 in 105 french farrow-to-finish pig farms. in each farm, a batch of contemporary fattening pigs housed in the same room was followed throughout the fattening period. salmonella shedding was assessed on environmental samples of faecal material (taken by means of pairs of gauze socks) analysed by classical b ...200415099720
bacteriophages and insertion sequences of chromobacterium violaceum atcc 12472.a fluid genome is a great advantage to prokaryotes, enabling quick adaptation to various types of ecological niches and to diverse environmental selective pressures. a substantial portion of these sudden changes is mediated by lateral gene transfer (lgt), through genetic recombination mechanisms, such as transformation, conjugation and transduction. the recent sequencing of several organisms has offered a new approach to the study of lgt, using comparison and analysis of nucleotide sequences dis ...200415100989
host and bacterial factors affecting induction of immune responses to flagellin expressed by attenuated salmonella vaccine strains.previous observations demonstrated that the delivery of recombinant salmonella enterica serovar dublin strains to mice via mucosal routes did not efficiently activate systemic and secreted antibody responses to either type d flagellin or genetically fused heterologous b-cell epitopes, thus reducing the usefulness of the protein as a carrier of epitopes for vaccine purposes. in this work, we investigated murine systemic and mucosal flagellin immunogenicity after oral immunization with attenuated ...200415102762
bacterial and host factors involved in the major histocompatibility complex class ib-restricted presentation of salmonella hsp 60: novel pathway.previously, a peptide epitope derived from the hsp 60 molecule of salmonella that is presented by the major histocompatibility complex (mhc) class ib molecule qa-1 to cd8(+) cytotoxic t cells (ctls) was described. in the present study we investigated the salmonella-induced processing and presentation pathway for generating this qa-1-restricted epitope. live bacteria and, to a lesser extent, opsonized heat-killed bacteria are able to sensitize target cells for lysis by salmonella-specific ctl. in ...200415102795
functional transfer of salmonella pathogenicity island 2 to salmonella bongori and escherichia coli.the type iii secretion system (t3ss) encoded by the salmonella pathogenicity island 2 (spi2) has a central role in systemic infections by salmonella enterica and for the intracellular phenotype. intracellular s. enterica uses the spi2-encoded t3ss to translocate a set of effector proteins into the host cell, which modify host cell functions, enabling intracellular survival and replication of the bacteria. we sought to determine whether specific functions of the spi2-encoded t3ss can be transferr ...200415102800
biophysical characterization of endotoxin inactivation by nk-2, an antimicrobial peptide derived from mammalian nk-lysin.nk-2, a membrane-acting antimicrobial peptide, was derived from the cationic core region of porcine nk-lysin and consists of 27 amino acid residues. it adopts an amphipathic, alpha-helical secondary structure and has been shown to interact specifically with membranes of negatively charged lipids. we therefore investigated the interaction of nk-2 with lipopolysaccharide (lps), the main, highly anionic component of the outer leaflet of the outer membrane of gram-negative bacteria, by means of biop ...200415105110
international spread of bla(cmy-2)-mediated cephalosporin resistance in a multiresistant salmonella enterica serovar heidelberg isolate stemming from the importation of a boar by denmark from canada. 200415105160
phospholipid molecular species profiles of tectiviruses infecting gram-negative and gram-positive hosts.the phospholipid (pl) molecular species compositions of bacteriophages prd1 and bam35 as well as their respective hosts were determined quantitatively using liquid chromatography/electrospray ionization mass-spectrometry (lc-esi-ms) and backed up by gas-chromatographic/mass-spectrometric (gc-ms) analysis of the total fatty acids (fas). the results showed that both viruses contain significantly more phosphatidylglycerol (pg) and less phosphatidylethanolamine (pe) than the host membranes. only mod ...200415110530
complete amino acid sequence and location of omp-28, an important immunogenic protein from salmonella enterica serovar typhi.omp-28 isolated from salmonella enterica serovar typhi presented a subunit molecular mass of 9,632 da by maldi-tof ms. it was denatured, s-alkylated, and 1) directly submitted to edman sequencing, 2) cleaved with cnbr, and 3) hydrolyzed either with endoproteinase glu-c or asp-n. the major cnbr peptide containing the c-terminal portion of omp-28 was isolated by tricine-sds-page and electroblotted whereas omp-28 enzymatic peptides were isolated by c18-rp-hplc. all peptides were sequenced. this app ...200415115184
class 1 integrons in various salmonella enterica serovars isolated from animals and identification of genomic island sgi1 in salmonella enterica var. meleagridis.to determine the prevalence of integron-mediated antibiotic resistance in a diverse sample set of salmonella enterica isolated from animals.200415117931
antimicrobial activity of copper surfaces against suspensions of salmonella enterica and campylobacter jejuni.salmonella enterica and campylobacter jejuni are amongst the more prevalent bacterial pathogens that cause foodborne diseases. these microorganisms are common contaminants of poultry and poultry products. this study was aimed to evaluate the antibacterial activity of metallic copper surfaces on these important enteropathogens, and to determine the potential acquisition of copper by food exposed to this metal.200415119960
differences in the carriage and the ability to utilize the serotype associated virulence plasmid in strains of salmonella enterica serotype typhimurium investigated by use of a self-transferable virulence plasmid, pog669.most strains of salmonella enterica subspecies enterica serotype typhimurium (s. typhimurium) naturally harbour a virulence plasmid which carries the salmonella plasmid virulence (spv) genes. however, isolates belonging to certain phage types are generally found without the plasmid. we have utilized a self-transferable virulence plasmid, pog669 to investigate the effect of introduction of spv genes into strains of such phage types. the use of the co-integrate plasmid, pog669, was validated on a ...200415120160
salmonella impairs rilp recruitment to rab7 during maturation of invasion vacuoles.after invasion of epithelial cells, salmonella enterica typhimurium resides within membrane-bound vacuoles where it survives and replicates. like endocytic vesicles, the salmonella-containing vacuoles (scvs) undergo a maturation process that involves sequential acquisition of rab5 and rab7 and displacement toward the microtubule-organizing center. however, scvs fail to merge with lysosomes and instead develop subsequently into a filamentous network that extends toward the cell periphery. we foun ...200415121880
salmonella enterica serotype paratyphi:a induced acute diarrhea. 200415122052
microbial-gut interactions in health and disease. epithelial cell responses.pathogenic bacteria use many strategies to secure their survival within the host. enteropathogens exploit intestinal epithelial cells in many ways, including the manipulation of normal cellular functioning, or of cellular structural components, or by the induction of signalling pathways, such as the production of pro-inflammatory cytokines. however, the enterocyte warns the host of impending danger and, in turn, elicits a protective response. pathogens are detected by epithelial cells owing to t ...200415123076
a bacterial acetyltransferase capable of regioselective n-acetylation of antibiotics and histones.the salmonella enterica chromosomally encoded aac(6')-iy has been shown to confer broad aminoglycoside resistance in strains in which the structural gene is expressed. the three-dimensional structures reported place the enzyme in the large gcn5-related n-acetyltransferase (gnat) superfamily. the structure of the coa-ribostamycin ternary complex allows us to propose a chemical mechanism for the reaction, and comparison with the mycobacterium tuberculosis aac(2')-coa-ribostamycin complex allows us ...200415123251
ompr and leuo positively regulate the salmonella enterica serovar typhi omps2 porin gene.the salmonella enterica serovar typhi omps2 gene codes for a 362-amino-acid outer membrane protein that contains motifs common to the porin superfamily. it is expressed at very low levels compared to the major ompc and ompf porins, as observed for s. enterica serovar typhi omps1, escherichia coli ompn, and klebsiella pneumoniae ompk37 quiescent porins. a region of 316 bp, between nucleotides -413 and -97 upstream of the transcriptional start point, is involved in negative regulation, as its remo ...200415126450
precise excision of the large pathogenicity island, spi7, in salmonella enterica serovar typhi.the large pathogenicity island (spi7) of salmonella enterica serovar typhi is a 133,477-bp segment of dna flanked by two 52-bp direct repeats overlapping the pheu (phenylalanyl-trna) gene, contains 151 potential open reading frames, and includes the viab operon involved in the synthesis of vi antigen. some clinical isolates of s. enterica serovar typhi are missing the entire spi7, due to its precise excision; these strains have lost the ability to produce vi antigen, are resistant to phage vi-ii ...200415126483
salmonella enterica serovar typhi strains from which spi7, a 134-kilobase island with genes for vi exopolysaccharide and other functions, has been deleted.salmonella enterica serovar typhi has a 134-kb island of dna identified as salmonella pathogenicity island 7 (spi7), inserted between pheu and 'pheu (truncated), two genes for trna(phe). spi7 has genes for vi exopolysaccharide, for type ivb pili, for putative conjugal transfer, and for sope bacteriophage. pulsed-field gel electrophoresis following digestion with the endonuclease i-ceui, using dna from a set of 120 wild-type strains of serovar typhi assembled from several sources, identified eigh ...200415126484
contribution of the rpoa c-terminal domain to stimulation of the salmonella enterica hila promoter by hilc and hild.expression of invasion genes in salmonella pathogenicity island 1 (spi-1) is mainly driven by the transcriptional activator hila. transcription of hila is subject to complex control and is stimulated by the spi-1-encoded hilc and hild proteins. the c-terminal domain of rpoa contributes to hila activation by hilc/d under certain inducing conditions.200415126488
a multistate outbreak of salmonella enterica serotype saintpaul infections linked to mango consumption: a recurrent theme. 200415127356
subpopulation characteristics of egg-contaminating salmonella enterica serovar enteritidis as defined by the lipopolysaccharide o chain.characterization of salmonella enterica serovar enteritidis was refined by incorporating new data from isolates obtained from avian sources, from the spleens of naturally infected mice, and from the united kingdom into an existing lipopolysaccharide (lps) o-chain compositional database. from least to greatest, the probability of avian isolates producing high-molecular-mass lps o chain ranked as follows: pooled kidney, liver, and spleen; intestine; cecum; ovary and oviduct; albumen; yolk; and who ...200415128529
molecular characterization of class 1 integrons from irish thermophilic campylobacter spp.in this study a large random collection (n = 378) of irish thermophilic campylobacter isolates were investigated for the presence of integrons, genetic elements associated with the dissemination of antimicrobial resistance.200415128721
toll-like receptor 4 dependence of innate and adaptive immunity to salmonella: importance of the kupffer cell network.mammalian cells recognize lps from gram-negative bacteria via the toll-like receptor 4 (tlr4) complex. during experimental salmonella infection, c3h/hej mice carrying a dominant-negative mutation in tlr4 exhibited delayed chemokine production, impaired no generation, and attenuated cellular immune responses. however, dramatically enhanced bacterial growth within the kupffer cell network before the recruitment of inflammatory cells appeared to be primarily responsible for the early demise of salm ...200415128808
cell-to-cell signalling in escherichia coli and salmonella enterica.cell-to-cell signalling in prokaryotes that leads to co-ordinated behaviour has been termed quorum sensing. this type of signalling can have profound impacts on microbial community structure and host-microbe interactions. the gram-negative quorum-sensing systems were first discovered and extensively characterized in the marine vibrios. some components of the vibrio systems are present in the classical genetic model organisms escherichia coli and salmonella enterica. both organisms encode a signa ...200415130116
evaluation of rapid diagnostic tests for typhoid fever.laboratory diagnosis of typhoid fever requires isolation and identification of salmonella enterica serotype typhi. in many areas where this disease is endemic, laboratory capability is limited. recent advances in molecular immunology have led to the identification of sensitive and specific markers for typhoid fever and technology to manufacture practical and inexpensive kits for their rapid detection. we evaluated three commercial kits for serologic diagnosis of typhoid fever. patients presentin ...200415131144
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