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chromosomally encoded blacmy-2 located on a novel sxt/r391-related integrating conjugative element in a proteus mirabilis clinical isolate.integrating conjugative elements (ices) are mobile genetic elements that can transfer from the chromosome of a host to the chromosome of a new host through the process of excision, conjugation, and integration. although sxt/r391-related ices, originally demonstrated in vibrio cholerae o139 isolates, have become prevalent among v. cholerae isolates in asia, the prevalence of the ices among gram-negative bacteria other than vibrio spp. remains unknown. in addition, sxt/r391-related ices carrying g ...201020566768
cation selectivity by the cora mg2+ channel requires a fully hydrated cation.the cora mg(2+) channel is the primary uptake system in about half of all bacteria and archaea. however, the basis for its mg(2+) selectivity is unknown. previous data suggested that cora binds a fully hydrated mg(2+) ion, unlike other ion channels. the crystal structure of thermotoga maritima cora shows a homopentamer with two transmembrane segments per monomer connected by a short periplasmic loop. this highly conserved loop, (281)efmpelkws(289) in salmonella enterica serovar typhimurium cora, ...201020568735
development and evaluation of multilocus variable number tandem repeat analysis for fine typing and phylogenetic analysis of salmonella enterica serovar typhimurium.we identified 16 variable number tandem repeat (vntr) loci for salmonella enterica serovar typhimurium. these vntrs were evaluated with panels of 183 diverse isolates, 203 closely related isolates and 54 isolates from seven outbreaks. the evaluations revealed that five of the 16 vntrs had diversity values greater than 0.5, and three (sttr5, sttr6 and sttr10) were hypervariable. the results obtained from the outbreak isolates suggested that the 16 vntrs were considerably stable in isolates recove ...201020573417
emergence and characterization of salmonella enterica serovar typhimurium phage type dt191a.the emergence of a previously undefined phage type of salmonella enterica serovar typhimurium, designated dt191a, occurred in england and wales in july 2008. the new strain exhibits a number of distinctive phenotypic and genotypic features. this report provides the tools necessary to track s. typhimurium dt191a globally.201020573861
characterization of anti-salmonella enterica serotype typhi antibody responses in bacteremic bangladeshi patients by an immunoaffinity proteomics-based technology.salmonella enterica serotype typhi is the cause of typhoid fever and a human-restricted pathogen. currently available typhoid vaccines provide 50 to 90% protection for 2 to 5 years, and available practical diagnostic assays to identify individuals with typhoid fever lack sensitivity and/or specificity. identifying immunogenic s. typhi antigens expressed during human infection could lead to improved diagnostic assays and vaccines. here we describe a platform immunoaffinity proteomics-based techno ...201020573880
glycomimicry: display of the gm3 sugar epitope on escherichia coli and salmonella enterica sv typhimurium.oligosaccharides present on the surface of pathogenic bacteria play an important role in their interaction with their host. bacteria with altered cell surface structures can be used to study these interactions, and glycoengineering represents a tool to display a glycoepitope on a different bacterium. here, we present non-pathogenic escherichia coli and salmonella enterica serovar typhimurium expressing the sialyllactose oligosaccharide epitope of the ganglioside gm3. by expression of the galacto ...201020574043
new approach to study the mechanism of antimicrobial protection of an active packaging.this article reports on the antimicrobial efficiency of a new active packaging concept based on the use of two essential oils (cinnamon and oregano) and their chemical descriptors (cinnamaldehyde, thymol, and carvacrol) against the gram-positive bacterium listeria monocytogenes, the gram-negative bacterium salmonella choleraesuis, the yeast candida albicans, and the mold aspergillus flavus. complete inhibition of these microorganisms with either bactericidal or bacteriostatic effect has been dem ...201020575672
enteric bacterial pathogens with zoonotic potential isolated from farm-raised deer.the raising of captive white-tailed deer (odocoileus virginianus) is a growing agricultural industry in ohio as it is in several other areas of the united states and around the world. pooled fecal samples were collected from 30 white-tailed deer confinement facilities. samples were cultured for five enteric bacterial pathogens. premise prevalence rates were as follows: escherichia coli o157, 3.3%; listeria monocytogenes, 3.3%; salmonella enterica, 0%; yersinia enterocolitica, 30%; and clostridiu ...201020575673
interleukin-17a is required to suppress invasion of salmonella enterica serovar typhimurium to enteric mucosa.salmonella enterica serovar typhimurium (s. typhimurium) causes a localized enteric infection and its elimination is dependent on a t helper type 1 immune response. however, the mechanism of the protective immune response against the pathogen in gut-associated lymphoid tissue (galt) at an early stage of the infection is not yet clarified. here, we show that interleukin-17a (il-17a) was constitutively expressed in galt; it was also detected on crypt and epithelial cells of the small intestine. ne ...201020575990
nationwide outbreak of salmonella enterica serotype 4,12:i:- infections in france, linked to dried pork sausage, march-may 2010.in may 2010, a nationwide excess of infections with the specific monophasic variant salmonella enterica serotype 4,12:i:- was investigated in france. subtyping with multilocus variable number of tandem repeats analysis revealed a distinct epidemic strain within this excess. epidemiological investigations identified a dried pork sausage sold by a particular chain of supermarkets as the likely vehicle of transmission. the suspected batches have been withdrawn and recalled.201020576238
comparison of vi serology and nested pcr in diagnosis of chronic typhoid carriers in two different study populations in typhoid endemic area of india.for detection of chronic typhoid carriers, nested pcr targeting flagellin the gene of salmonella enterica subspecies enterica serotype typhi was carried out on dna extracted from hepatobiliary specimens from 424 autopsies which were apparently free from gallbladder pathology on postmortem examination. the second study population was 508 healthy volunteers, who did not suffer from typhoid fever during the preceding year and whose sera were subjected to detection of carriage by estimation of vi an ...201020578552
transferable class 1 and 2 integrons in escherichia coli and salmonella enterica isolates of human and animal origin in lithuania.antibiotic-resistant escherichia coli (n = 191) and salmonella enterica (n = 87) isolates of human and animal origin obtained in lithuania during 2005-2008 were characterized for the presence and diversity of class 1 and 2 integrons. e. coli isolates were obtained from patients with urinary tract infections (utis) (n = 59) and both healthy and diseased farm animals, including poultry (n = 54), swine (n = 35), and cattle (n = 43). isolates of non-typhoidal s. enterica were recovered from salmonel ...201020578916
salmonellae in food stuffs of plant origin and their implications on human health.salmonella enterica is one of the most common causes of food-borne infection in human beings. cases of salmonella infection have been decreasing in europe in the last ten years, yet, salmonella infections are still the main cause of acute diarrhea syndrome. globalization has caused the international food industry to increase the production of collective nutrition produce and products. this has intensified the need for authorized and accredited laboratories to monitor microbiological food safety. ...201020582445
outbreak of salmonellosis caused by salmonella enterica serovar newport mdr-ampc in a large animal veterinary teaching hospital.nosocomial salmonellosis is an important problem for large animal veterinary teaching hospitals (vths).201020584143
plasmid-mediated resistance to cephalosporins in salmonella enterica serovar typhi.this study characterized a cephalosporin-resistant salmonella enterica serovar typhi isolate. the organism possessed a plasmid encoding the ctx-m-15 extended-spectrum-beta-lactamase. this plasmid is the determinant for the phenotype of cephalosporin resistance and is transferrable among enterobacteriaceae.201020585124
live recombinant salmonella typhi vaccines constructed to investigate the role of rpos in eliciting immunity to a heterologous antigen.we hypothesized that the immunogenicity of live salmonella enterica serovar typhi vaccines expressing heterologous antigens depends, at least in part, on its rpos status. as part of our project to develop a recombinant attenuated s. typhi vaccine (rastyv) to prevent pneumococcal diseases in infants and children, we constructed three rastyv strains synthesizing the streptococcus pneumoniae surface protein pspa to test this hypothesis. each vector strain carried ten engineered mutations designed t ...201020585446
engineering of glycerol dehydrogenase for improved activity towards 1, 3-butanediol.the objective of this study was to use protein engineering techniques to enhance the catalytic activity of glycerol dehydrogenase (glydh) on racemic 1, 3-butanediol (1, 3-bdo) for the bioproduction of the important pharmaceutical intermediate 4-hydroxy-2-butanone. three glydh genes (glda) from escherichia coli k-12, salmonella enterica, and klebsiella pneumoniae mgh78578 were shuffled to generate a random mutagenesis library. the nitroblue tetrazolium/phenazine methosulfate high throughput scree ...201020585771
acc-1 beta-lactamase-producing salmonella enterica serovar typhi, india. 201020587199
salmonella enterica enteritidis arthritis following trauma in a child with thalassemia major.osteoarticular infections caused by non-typhi salmonella are exceptionally encountered. we report a case of a bacteriologically documented knee joint infection due to salmonella enterica serotype enteritidis, following trauma in a child with thalassemia major. emergency arthrotomy combined with antimicrobial therapy was helpful in eradication of infection. physicians should be aware of this rare manifestation of non-typhi salmonella infections in thalassemic patients.201020589479
perceptions regarding workplace hazards at a veterinary teaching hospital.objective: to assess perceptions of personnel working at a veterinary teaching hospital regarding risks of occupational hazards and compare those perceptions with assessments made by occupational safety experts.201020590501
functional analysis of the c-terminal domain of the wbap protein that mediates initiation of o antigen synthesis in salmonella enterica.wbap catalyzes the transfer of galactose-1-phosphate onto undecaprenyl phosphate (und-p). the enzyme belongs to a large family of bacterial membrane proteins required for initiation of the synthesis of o antigen lipopolysaccharide and polysaccharide capsules. previous work in our laboratory demonstrated that the last transmembrane helix and c-terminal tail region of wbap (wbap(ct)) are sufficient for enzymatic activity. here, we demonstrate the cytoplasmic location of the wbap c-terminal tail an ...201020591829
ribonucleotide reductases of salmonella typhimurium: transcriptional regulation and differential role in pathogenesis.ribonucleotide reductases (rnrs) are essential enzymes that carry out the de novo synthesis of deoxyribonucleotides by reducing ribonucleotides. there are three different classes of rnrs (i, ii and iii), all having different oxygen dependency and biochemical characteristics. salmonella enterica serovar typhimurium (s. typhimurium) harbors class ia, class ib and class iii rnrs in its genome. we have studied the transcriptional regulation of these three rnr classes in s. typhimurium as well as the ...201020593029
salmonella-regulated lipopolysaccharide modifications.salmonella enterica are gram-negative enteric pathogens that cause typhoid fever and gastroenteritis in humans. many bacteria, including salmonella, use signal transduction cascades such as two-component regulatory systems to detect and respond to stimuli in the local microenvironment. during infection, environmental sensing allows bacteria to regulate gene expression to evade host immune defenses and thrive in vivo. activation of the salmonella two-component regulatory systems phop-phoq and pmr ...201020593264
the o-antigen of salmonella enterica o13 and its relation to the o-antigen of escherichia coli o127.the following structure of the o-polysaccharide (o-antigen) of salmonella enterica o13 was established by chemical analyses along with 2d (1)h and (13)c nmr spectroscopy: -->2)-alpha-l-fucp-(1-->2)-beta-d-galp-(1-->3)-alpha-d-galpnac-(1-->3)-alpha-d-glcpnac-(1--> the o-antigen of s. enterica o13 was found to be closely related to that of escherichia coli o127, which differs only in the presence of a galnac residue in place of the glcnac residue and o-acetylation. the location of the o-acetyl gro ...201020594547
complete genome sequence of the incompatibility group i1 plasmid r64.a streptomycin and tetracycline resistance plasmid r64 isolated from salmonella enterica serovar typhimurium belongs to the incompatibility group i1 (inci1). the dna sequence of the r64 conjugative transfer region was described previously (komano et al., 2000). here, we report the complete genome sequence of r64. in the circular double-stranded r64 genome with 120,826bp, 126 complete orfs are predicted. in addition, 2 and 6 different kinds of proteins are produced by translational reinitiation a ...201020594994
community-acquired bloodstream infections in africa: a systematic review and meta-analysis.data on the prevalence and causes of community-acquired bloodstream infections in africa are scarce. we searched three databases for studies that prospectively studied patients admitted to hospital with at least a blood culture, and found 22 eligible studies describing 58 296 patients, of whom 2051 (13.5%) of 15 166 adults and 3527 (8.2%) of 43 130 children had bloodstream infections. 1643 (29.1%) non-malaria bloodstream infections were due to salmonella enterica (58.4% of these non-typhoidal sa ...201020510282
a multiplex single nucleotide polymorphism typing assay for detecting mutations that result in decreased fluoroquinolone susceptibility in salmonella enterica serovars typhi and paratyphi a.decreased susceptibility to fluoroquinolones has become a major problem for the successful therapy of human infections caused by salmonella enterica, especially the life-threatening typhoid and paratyphoid fevers.201020511368
mutations affecting export and activity of cytolysin a from escherichia coli.cytolysin a (known as clya, hlye, and shea) is a cytolytic pore-forming protein toxin found in several escherichia coli and salmonella enterica strains. the structure of its water-soluble monomeric form and that of dodecameric clya pores is known, but the mechanisms of clya export from bacterial cells and of pore assembly are only partially understood. here we used site-directed mutagenesis to study the importance of different regions of the e. coli clya protein for export and activity. the data ...201020511497
a 96-well plate fluorescence assay for assessment of cellular permeability and active efflux in salmonella enterica serovar typhimurium and escherichia coli.multiply antibiotic-resistant (mar) mutants of escherichia coli and salmonella enterica are characterized by reduced susceptibility to several unrelated antibiotics, biocides and other xenobiotics. porin loss and/or active efflux have been identified as a key mechanisms of mar. a single rapid test was developed for mar.201020513705
elucidation of antimicrobial susceptibility profiles and genotyping of salmonella enterica isolates from clinical cases of salmonellosis in new mexico in 2008.in this study, we investigated the antimicrobial susceptibility profiles and the distribution of some well known genetic determinants of virulence in clinical isolates of salmonella enterica from new mexico. the minimum inhibitory concentrations (mics) for various antimicrobials were determined by using the e-test strip method according to clsi guidelines. virulence genotyping was performed by polymerase chain reaction (pcr) using primers specific for known virulence genes of salmonella enterica ...201020514366
absence of poly(adp-ribose) polymerase 1 delays the onset of salmonella enterica serovar typhimurium-induced gut inflammation.the immune system comprises an innate and an adaptive immune response to combat pathogenic agents. the human enteropathogen salmonella enterica serovar typhimurium invades the intestinal mucosa and triggers an early innate proinflammatory host gene response, which results in diarrheal disease. several host factors, including transcription factors and transcription coregulators, are involved in the acute early response to salmonella infection. we found in a mouse model of enterocolitis induced by ...201020515923
salmonella enterica replication in hemophagocytic macrophages requires two type three secretion systems.salmonella enterica serotype typhimurium is a natural pathogen of mice, which acquire the bacteria orally and develop systemic acute infections that can become subacute to chronic infections. s. typhimurium can reside within hemophagocytic macrophages (hms) in sv129s6 mice, an slc11a1/nramp1(+/+) inbred strain. hms are activated macrophages which have ingested viable hematopoietic cells and are a key characteristic of infectious and inflammatory diseases. here we show that modest s. typhimurium ...201020515933
splice-variant 1 of the ancient domain protein 2 (acdp2) complements the magnesium-deficient growth phenotype of salmonella enterica sv. typhimurium strain mm281.evidence arguing for the existence of genes encoding for proteins directly involved in the transport of mg2+ through the cytoplasmic membrane have accumulated over the last few years. gene acdp2 (ancient conserved domain protein 2; old name cnnm2, cyclin m2) is one such gene. acdp2 is a distant homologue of the bacterial gene corc, which is known to be involved in cobalt resistance. we have previously demonstrated that the over-expression of the human mg2+ carrier slc41a1 partly complements the ...201020519162
characterization of antimicrobial resistance of recent salmonella enterica serovar gallinarum isolates from chickens in south korea.salmonella enterica serovar gallinarum isolates (n=105) from chickens in south korea between 2002 and 2007 were tested for antimicrobial susceptibility by determining minimum inhibitory concentrations of 16 antimicrobials, and their predominant resistance profiles were genetically characterized. most isolates (99/105; 94.3%) were resistant to nalidixic acid and resistant/intermediately resistant to fluoroquinolones, and 63.8% (67/105) of the isolates were resistant to three or more antimicrobial ...201020544426
unphosphorylated csgd controls biofilm formation in salmonella enterica serovar typhimurium.the transcriptional regulator csgd of salmonella enterica serovar typhimurium (s. typhimurium) is a major regulator of biofilm formation required for the expression of csgba, which encodes curli fimbriae, and adra, coding for a diguanylate cyclase. csgd is a response regulator with an n-terminal receiver domain with a conserved aspartate (d59) as a putative target site for phosphorylation and a c-terminal luxr-like helix-turn-helix dna binding motif, but the mechanisms of target gene activation ...201020545866
multiresistant salmonella enterica serovar 4,[5],12:i:- in europe: a new pandemic strain?a marked increase in the prevalence of s. enterica serovar 4,[5],12:i:- with resistance to ampicillin, streptomycin, sulphonamides and tetracyclines (r-type assut) has been noted in food-borne infections and in pigs/pig meat in several european countries in the last ten years. one hundred and sixteen strains of s. enterica serovar 4,[5],12:i:- from humans, pigs and pig meat isolated in england and wales, france, germany, italy, poland, spain and the netherlands were further subtyped by phage typ ...201020546690
enterobacterial tumor colonization in mice depends on bacterial metabolism and macrophages but is independent of chemotaxis and motility.despite promising results and increasing attention in bacterial cancer therapy, surprisingly little is known about initial tumor colonization and the interaction between bacteria and surrounding tumor tissue. here, we analyzed the role of chemotaxis, motility, and metabolism both in escherichia coli and salmonella enterica serovar typhimurium strains upon intravenous injection into tumor-bearing mice. in contrast to previous models, we found that chemotaxis and motility do not play a significant ...201020547100
isolation and characterization of a novel analyte from bacillus subtilis sc-8 antagonistic to bacillus cereus.in this study, an effective substance was isolated from bacillus subtilis sc-8, which was obtained from traditionally fermented soybean paste, cheonggukjang. the substance was purified by hplc, and its properties were analyzed. it had an adequate antagonistic effect on bacilluscereus, and its spectrum of activity was narrow. when tested on several gram-negative and gram-positive foodborne pathogenic bacteria such as salmonella enterica, salmonella enteritidis, staphylococcus aureus, and listeria ...201020547349
antimicrobial resistance and subtyping of salmonella enterica subspecies enterica serovar enteritidis isolated from human outbreaks and poultry in southern brazil.to investigate antimicrobial resistance, 96 salmonella enterica subspecies enterica serovar enteritidis strains isolated from salmonellosis outbreaks and poultry-related products obtained in southern brazil were analyzed. macrorestriction patterns, obtained by pulsed-field gel electrophoresis and phage types, were assessed. although 43.75% of samples were sensitive to all drugs tested, resistance to sulfonamide (34.37%), trimethoprim-sulfamethoxazole (25.00%), nalidixic acid (14.58%), streptomyc ...201020548083
synthesis and antimicrobial activity of n,n'-bis(2-hydroxylbenzyl)-1,2-ethanediamine derivatives.a series of n,n'-bis(2-hydroxylbenzyl)-1,2-ethanediamine derivatives and its schiff bases were synthesized, characterized and screened for in vitro antimicrobial activity against staphylococcus aureus, pseudomonas aeruginosa and salmonella enterica. result indicated that the ethylenediamine derivatives, n,n'-bis(2-hydroxy-5-bromobenzyl)-1,2-ethanediamine (21), and n,n'-bis(2-hydroxy-5-chlorobenzyl)-1,2-ethanediamine (22) showed the most favorable antimicrobial activity exhibiting lc(50) of 11.6 ...201020548968
salmonella enterica serovar typhi has a 4.1 kb genetic island inserted within the sapabcdf operon that causes loss of resistance to the antimicrobial peptide protamine.to investigate the association between the presence of a genetic island inserted within the sapabcdf operon of salmonella typhi and the susceptibility to antimicrobial peptides.201020551214
antimicrobial properties of prunin, a citric flavanone glucoside, and its prunin 6″-o-lauroyl ester.to determine the antimicrobial potential of prunin (p), a flavanone glucoside resulting from the hydrolysis of naringin present in grapefruit, and of its prunin 6″-o-lauroyl ester (pl), synthesized by enzymatic catalysis.201020553344
epidemiology and interaction of salmonella enterica serovar derby, infantis and typhimurium with porcine alveolar macrophages.in this study we were interested in the serovars which are frequently isolated from pigs, i.e. s. typhimurium, s. derby and s. infantis. first we collected different isolates of s. infantis and s. derby and compared them by macrorestriction analysis. in the second part of the study we infected porcine alveolar macrophages (pams) with representative strains of these serovars and s. typhimurium and determined intracellular survival, cytotoxicity and cytokine response. in s. derby, 17 different pro ...201020554127
deletion of a prophage-like element causes attenuation of salmonella enterica serovar enteritidis and promotes protective immunity.salmonella enterica serovar enteritidis (s. enteritidis) is a wide host range serovar belonging to the s. enterica genus. worldwide, it is one of the most frequent causes of food borne disease. similar to s. typhimurium, some virulence genes of s. enteritidis are located in pathogenicity islands and prophages. in this study we have generated a mutant strain of s. enteritidis lacking a prophage-like element, denominated varphise12. the resulting mutant strain was attenuated and promoted protectiv ...201020558245
the cyclotide cycloviolacin o2 from viola odorata has potent bactericidal activity against gram-negative bacteria.to determine the antibacterial activity of small cyclic plant proteins, i.e. cyclotides, and the importance of the surface exposed charged residues for activity.201020558471
use of a mixture of bacteriophages for biological control of salmonella enterica strains in compost.bacteriophages specific to salmonella strains were isolated from sewage effluent and characterized. a five-strain bacteriophage mixture was applied to dairy manure compost inoculated with salmonella enterica serotype typhimurium. bacteriophage treatment resulted in a greater than 2-log-unit reduction of salmonella within 4 h at all moisture levels compared to the controls.201020525859
salmonella-allies in the fight against cancer.cancer has become the second ranking cause of death in the industrialized world. conventional anti-cancer therapies such as surgery, radiotherapy, and chemotherapy are effective in the treatment of solid tumors only to some extent. furthermore, they are often associated with severe side effects. use of bacteria as alternative cancer therapeutics has sporadically been followed over more than a century. the potential to target and colonize solid tumors could be shown for many different bacteria in ...201020526574
expression of chicken leap-2 in the reproductive organs and embryos and in response to salmonella enterica infection.in recent years host antimicrobial peptides and proteins have been recognised as key mediators of the innate immune response in many vertebrate species, providing the first line of defense against potential pathogens. in chickens a number of cationic antimicrobial peptides have been recently identified. however, although these peptides have been studied extensively in the avian gastrointestinal tract, little is known about their function in the chicken reproductive organs and embryos. chicken li ...201020526889
tracking salmonella contamination in various watersheds and phenotypic and genotypic diversity.salmonella enterica is an important foodborne pathogen, and contamination of surface and ground water that may result from various human activities, such as animal production and urbanization, may contribute to the public health burden. the aims of this study was to determine the sources of salmonella contamination in four different types of watersheds and to assess the relative contribution of multidrug-resistant strains. eighty-six water samples collected from four different watershed systems, ...201020528467
successful treatment of late salmonella infections in total hip replacement - report of two cases.salmonella species can be rarely isolated from periprosthetic joint infections, however when present, are usually part of a severe septic clinical picture.201020529326
mass spectrometry-based quantitative proteomic analysis of salmonella enterica serovar enteritidis protein expression upon exposure to hydrogen peroxide.salmonella enterica, a common food-borne bacterial pathogen, is believed to change its protein expression profile in the presence of different environmental stress such as that caused by the exposure to hydrogen peroxide (h2o2), which can be generated by phagocytes during infection and represents an important antibacterial mechanism of host cells. among salmonella proteins, the effectors of salmonella pathogenicity island 1 and 2 (spi-1 and spi-2) are of particular interest since they are expres ...201020529336
phylogenetic incongruence arising from fragmented speciation in enteric bacteria.evolutionary relationships among species are often assumed to be fundamentally unambiguous, where genes within a genome are thought to evolve in concert and phylogenetic incongruence between individual orthologs is attributed to idiosyncrasies in their evolution. we have identified substantial incongruence between the phylogenies of orthologous genes in escherichia, salmonella, and citrobacter, or e. coli, e. fergusonii, and e. albertii. the source of incongruence was inferred to be recombinatio ...201020534528
copper homeostasis in salmonella is atypical and copper-cuep is a major periplasmic metal complex.salmonella enterica sv. typhimurium (s. enterica sv. typhimurium) has two metal-transporting p(1)-type atpases whose actions largely overlap with respect to growth in elevated copper. mutants lacking both atpases over-accumulate copper relative to wild-type or either single mutant. such duplication of atpases is unusual in bacterial copper tolerance. both atpases are under the control of merr family metal-responsive transcriptional activators. analyses of periplasmic copper complexes identified ...201020534583
recent advances in the field of salmonella typhi vaccines.typhoid fever, caused by the bacterium salmonella enterica serovar typhi, remains a significant cause of human death and disease throughout large areas of the world. although there are currently three vaccines available against s. typhi they have a number of significant drawbacks which drive the development of much-needed new and improved versions. here recent advances towards such vaccines, from basic research to human trials, are discussed.201020534981
the epidemiology of extraintestinal non-typhoid salmonella in israel: the effects of patients' age and sex.extraintestinal disease occurs in 5-8% of non-typhoid salmonella enterica (nts) infections and is more likely to be associated with hospitalization and death. the study examined the epidemiology of extraintestinal nts infections in israel and the possible effects of patients' age and sex. nts isolates passively submitted to the national salmonella reference center during 1996-2006 were the source for the study cohort. poisson regression models were used to assess incidence trends over the study ...201020535625
[induction and migration of cryptic/defective salmonella enterica prophages as a consequence of infection with lytic phages is an additional factor in stability of a coevolutionary vector].the influence of infection of natural isolates of salmonella enterica with lytic (nonlysogenic) phages on the expression of resident cryptic or defective prophages in host bacteria was studied. the induction of defective/cryptic phages after infection with nonlysogenic phages and packaging of bacterial chromosomal fragments in capsids of defective phages is demonstrated. this may lead to migration and wide distribution of both the genomes of defective phages per se and various fragments of the b ...201020536029
optical imaging of bacterial infection in living mice using deep-red fluorescent squaraine rotaxane probes.two structurally related fluorescent imaging probes allow optical imaging of bacterial leg infection models in living athymic and immunocompetent mice. structurally, the probes are comprised of a deep-red fluorescent squaraine rotaxane scaffold with two appended bis(zinc(ii)-dicolylamine) (bis(zn-dpa)) targeting ligands. the bis(zn-dpa) ligands have high affinity for the anionic phospholipids and related biomolecules that reside within the bacterial envelope, and they are known to selectively ta ...201020536173
effect of enrichment medium on real-time detection of salmonella enterica from lettuce and tomato enrichment cultures.three enrichment broths commonly used for detection of salmonella (buffered peptone water [bpw], tryptic soy broth [tsb], and universal preenrichment broth [upb]) were compared for use in real-time sybr green pcr detection of salmonella introduced into enrichment cultures made from store-bought lettuce and tomatoes. the produce served as a source of normal plant microbiota to measure how well dna-based detection methods for salmonella work in a suspension of plant-associated bacteria that may be ...201020537259
structure and gene cluster of the o-antigen of salmonella enterica o60 containing 3-formamido-3,6-dideoxy-d-galactose.an o-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of salmonella enterica o60 strain g1462, and the following unique structure of the o-unit was determined by chemical analyses along with 2d (1)h and (13)c nmr spectroscopy: where fuc3nfo stands for 3-formamido-3,6-dideoxygalactose. the structure established is in agreement with the o-antigen gene cluster of s. enterica o60, which contains putative genes for the synthesis of gdp-d-man and dtdp-d-fuc3nfo, three gly ...201020538266
prevalence of decreased susceptibility to triclosan in salmonella enterica isolates from animals and humans and association with multiple drug resistance.previous laboratory studies have implicated triclosan as a possible selective force driving resistance to multiple antibiotics and have identified a number of triclosan resistance mechanisms in salmonella enterica. the aim of this work was to determine the prevalence of decreased susceptibility to triclosan in a panel of human and animal isolates of s. enterica and to identify the mechanisms of triclosan resistance in these strains. over 400 animal and human isolates of non-typhoidal salmonella ...201020541914
bacteriophage tailspike proteins as molecular probes for sensitive and selective bacterial detection.we report the use of genetically engineered tailspike proteins (tsps) from the p22 bacteriophage for the sensitive and selective detection of salmonella enterica serovar typhimurium. high yields of two mutant tsps, one with an n-terminal cysteine (n-cys) and another with a c-terminal cysteine (c-cys), have been obtained using recombinant protein expression and purification in escherichia coli. the mutant tsps did not have the native endorhamnosidase enzymatic activity of intact p22 phage as well ...201020541928
the phosphoinositide phosphatase sopb manipulates membrane surface charge and trafficking of the salmonella-containing vacuole.shifts in electrostatic surface charge of membranes have recently been highlighted as a significant factor contributing to protein targeting to the plasma membrane and nascent phagosomes. intracellular, vacuole-adapted pathogens may also regulate surface charge of their vacuoles to establish a replicative niche. since salmonella enterica serovar typhimurium controls trafficking of the salmonella-containing vacuole (scv) and inhibits its fusion with lysosomes, we investigated the contribution of ...201020542249
specific and rapid enumeration of viable but nonculturable and viable-culturable gram-negative bacteria by using flow cytometry.an issue of critical concern in microbiology is the ability to detect viable but nonculturable (vbnc) and viable-culturable (vc) cells by methods other than existing approaches. culture methods are selective and underestimate the real population, and other options (direct viable count and the double-staining method using epifluorescence microscopy and inhibitory substance-influenced molecular methods) are also biased and time-consuming. a rapid approach that reduces selectivity, decreases bias f ...201020543046
typhoid in kenya is associated with a dominant multidrug-resistant salmonella enterica serovar typhi haplotype that is also widespread in southeast asia.in sub-saharan africa, the burden of typhoid fever, caused by salmonella enterica serovar typhi, remains largely unknown, in part because of a lack of blood or bone marrow culture facilities. we characterized a total of 323 s. typhi isolates from outbreaks in kenya over the period 1988 to 2008 for antimicrobial susceptibilities and phylogenetic relationships using single-nucleotide polymorphism (snp) analysis. there was a dramatic increase in the number and percentage of multidrug-resistant (mdr ...201020392916
increased detection of extended spectrum beta-lactamase producing salmonella enterica and escherichia coli isolates from poultry.to gain more information on the genetic basis of the rapid increase in the number of isolates exhibiting non-wild type minimum inhibitory concentrations (mics) for cefotaxime observed since 2003, beta-lactamase genes of 22 salmonella enterica and 22 escherichia coli isolates from broilers in 2006 showing this phenotype were characterized by miniaturized micro-array, pcr and dna-sequencing. presence and size of plasmids were determined by s1-digest pulsed-field gel electrophoresis and further cha ...201020395076
ph sensing by intracellular salmonella induces effector translocation.salmonella enterica is an important intracellular bacterial pathogen of humans and animals. it replicates within host-cell vacuoles by delivering virulence (effector) proteins through a vacuolar membrane pore made by the salmonella pathogenicity island 2 (spi-2) type iii secretion system (t3ss). t3ss assembly follows vacuole acidification, but when bacteria are grown at low ph, effector secretion is negligible. we found that effector secretion was activated at low ph from mutant strains lacking ...201020395475
a mutation in tdca attenuates the virulence of salmonella enterica serovar typhimurium.the salmonella tdc operon encodes enzymes belonging to a metabolic pathway that degrades l-serine and l-threonine. the upregulation of the tdc operon and increased virulence of salmonella grown under oxygen-limiting conditions prompted us to investigate the role of the tdc operon in the pathogenesis of salmonella typhimurium. a salmonella strain carrying a null mutation in tdca, which encodes the transcriptional activator of the tdc operon, was impaired in mice infected intraperitoneally with th ...201020396961
transfer of enteric pathogens to successive habitats as part of microbial cycles.escherichia coli o157:h7 gfp and salmonella enterica typhimurium gfp passed through six successive habitats within a microbial cycle. pathogen cultures were introduced into cow dung or fodder. microscopically observed cells and cfus were monitored in fodder, dung, dung-soil mix, rhizosphere and phyllosphere of cress or oat plants grown in infested dung-soil mix, and in excrements of snails or mice fed with contaminated cress or oat shoots. both methods were sensitive enough to monitor cells and ...201020397013
an antisense rna that governs the expression kinetics of a multifunctional virulence gene.genome-wide transcriptome analyses of several bacterial species have recently uncovered a hitherto unappreciated amount of antisense transcription. however, the physiological role, regulation and significance of such antisense transcripts are presently unclear. we now report the identification of a cis-encoded 1.2 kb long antisense rna - termed amgr - that is complementary to the mgtc portion of the mgtcbr polycistronic message from salmonella enterica. the mgtcbr mrna specifies the mgtc protein ...201020398218
salmonella enterica bacteraemia: a multi-national population-based cohort study.salmonella enterica is an important emerging cause of invasive infections worldwide. however, population-based data are limited. the objective of this study was to define the occurrence of s. enterica bacteremia in a large international population and to evaluate temporal and regional differences.201020398281
characterization of antimicrobial resistant salmonella enterica serovars enteritidis and typhimurium isolates from animal and food in southern italy.in the last two decades, the emergence and spread of antimicrobial-resistant pathogens, among them salmonella, has become a serious health hazard worldwide, and specifically the high incidence of multidrug resistance has been encountered widely in many european countries. this study examines the antimicrobial susceptibility of salmonella enterica strains typhimurium and enteritidis isolated in campania and calabria region (southern italy) from animal and food of animal origin. the relationship o ...201020401533
assays of sensitivity of antibiotic-resistant bacteria to hydrogen peroxide and measurement of catalase activity.bacteria, in common with other organisms that take advantage of aerobic respiration, generate and accumulate reactive oxygen species (ros) that damage dna, fatty acids, and proteins. in addition, intracellular pathogens like salmonella enterica are exposed to an oxidate burst produced by host macrophages. the relative ability of aerobically growing bacteria to withstand oxidative stress and eliminate ros has a large impact of their fitness in vitro and in vivo. methods are described here to meas ...201020401588
measurements of heme levels and respiration rate in salmonella enterica serovar typhimurium.this chapter describes assays for the measurement of heme levels and the rate of respiration in bacteria. an assay of ala supplementation is described, in which the effect of exogenous ala in reversing sensitivity to hydrogen peroxide is an indication of a reduced flow through the heme biosynthesis pathway. a protocol for measurement of the relative amount of heme by a fluorescence assay, based on stripping the iron from the heme moiety, leaving a protoporphyrin molecule which fluoresces followi ...201020401589
a fast and highly sensitive blood culture pcr method for clinical detection of salmonella enterica serovar typhi.salmonella typhi causes an estimated 21 million new cases of typhoid fever and 216,000 deaths every year. blood culture is currently the gold standard for diagnosis of typhoid fever, but it is time-consuming and takes several days for isolation and identification of causative organisms. it is then too late to initiate proper antibiotic therapy. serological tests have very low sensitivity and specificity, and no practical value in endemic areas. as early diagnosis of the disease and prompt treatm ...201020403166
comparison of a semi-automated rep-pcr system and multilocus sequence typing for differentiation of salmonella enterica isolates.the accurate sub-typing of salmonella enterica isolates is essential for epidemiological investigations and surveillance of salmonella infections. salmonella isolates are currently identified using the kauffman-white serotyping scheme. multilocus sequence typing (mlst) schemes have been developed for the major bacterial pathogens including salmonella and have assisted in understanding the molecular epidemiology and population biology of these organisms. recently, the diversilab rep-pcr system ha ...201020114063
correlation of the genotoxic activation and kinetic properties of salmonella enterica serovar typhimurium nitroreductases snra and cnr with the redox potentials of nitroaromatic compounds and quinones.bacterial nitroreductases (nrs) catalyse the oxygen-insensitive reduction of several nitro-substituted compounds and quinones. snra and cnr nrs have been previously identified in salmonella enterica serovar typhimurium; they reduce several environmental nitro compounds that display mutagenic activity in the ames test. although some of their biochemical properties have been reported, the substrate specificity of each protein over mutagenic nitro compounds is unknown; even more, the possible relat ...201020118186
flagellated but not hyperfimbriated salmonella enterica serovar typhimurium attaches to and forms biofilms on cholesterol-coated surfaces.the asymptomatic, chronic carrier state of salmonella enterica serovar typhi occurs in the bile-rich gallbladder and is frequently associated with the presence of cholesterol gallstones. we have previously demonstrated that salmonellae form biofilms on human gallstones and cholesterol-coated surfaces in vitro and that bile-induced biofilm formation on cholesterol gallstones promotes gallbladder colonization and maintenance of the carrier state. random transposon mutants of s. enterica serovar ty ...201020118264
role of the c-terminal cytoplasmic domain of flha in bacterial flagellar type iii protein export.for construction of the bacterial flagellum, many of the flagellar proteins are exported into the central channel of the flagellar structure by the flagellar type iii protein export apparatus. flha and flhb, which are integral membrane proteins of the export apparatus, form a docking platform for the soluble components of the export apparatus, flih, flii, and flij. the c-terminal cytoplasmic domain of flha (flha(c)) is required for protein export, but it is not clear how it works. here, we analy ...201020118266
morphologic and cytokine profile characterization of salmonella enterica serovar typhimurium infection in calves with bovine leukocyte adhesion deficiency.the role of neutrophils in the pathogenesis of salmonella enterica typhimurium-induced ruminant and human enteritis and diarrhea has yet to be characterized with in vivo models. to address this question, the in vivo bovine ligated ileal loop model of nontyphoidal salmonellosis was used in calves with the naturally occurring bovine leukocyte adhesion deficiency (blad) mutation whose neutrophils are unable to extravasate and infiltrate the extravascular matrix. data obtained from 4 blad holstein c ...201020118318
salmonella sdia recognizes n-acyl homoserine lactone signals from pectobacterium carotovorum in vitro, but not in a bacterial soft rot.genomes of salmonella enterica isolates, including those linked to outbreaks of produce-associated gastroenteritis, contain sdia, which encodes a receptor of n-acyl homoserine lactones (ahl). ahl are the quorum-sensing signals used by bacteria to coordinately regulate gene expression within -their populations. because s. enterica does not produce its own ahl, sdia is hypothesized to function in the interspecies cross-talk with ahl-producing bacteria. under laboratory conditions, s. enterica resp ...201020121449
bacterial chemoreceptors: providing enhanced features to two-component signaling.bacteria perform chemotaxis utilizing core two-component signaling systems to which have been added enhanced features of signal amplification, sensory adaptation, molecular memory and high sensitivity over a wide dynamic range. chemoreceptors are central to the enhancements. these transmembrane homodimers associate in trimers and in clusters of signaling complexes containing from a few to thousands of receptors. receptor homodimers couple ligand occupancy and adaptational modification to transme ...201020122866
bacterial guanine nucleotide exchange factors sope-like and wxxxe effectors.subversion of rho family small gtpases, which control actin dynamics, is a common infection strategy used by bacterial pathogens. in particular, salmonella enterica serovar typhimurium, shigella flexneri, enteropathogenic escherichia coli (epec), and enterohemorrhagic escherichia coli (ehec) translocate type iii secretion system (t3ss) effector proteins to modulate the rho gtpases rhoa, cdc42, and rac1, which trigger formation of stress fibers, filopodia, and lamellipodia/ruffles, respectively. ...201020123714
enterococcus mundtii st4sa and lactobacillus plantarum 423 alleviated symptoms of salmonella infection, as determined in wistar rats challenged with salmonella enterica serovar typhimurium.wistar rats were administered daily with lactobacillus plantarum 423 and enterococcus mundtii st4sa through intragastric gavage (1 x 10(8) cfu of each strain and a combination of the two strains). sterile saline was used as placebo. after 7 days, the animals were challenged by infection with 2 x 10(8) cfu salmonella enterica serovar typhimurium. after 1 day of treatment with l. plantarum 423 and e. mundtii st4sa, the feed and water intake, and body weight of the rats increased. the faecal moistu ...201020127245
[construction of a promoter reporter array for antibiotic screening].we designed and constructed an antibiotic screening system by using antibiotic responsive genes as reporters. plasmid pcs26 carrying a promoterless luminescence reporter, luxcdabe, was used as the vector and the promoter regions of antibiotic responsive genes/operons from escherichia coli were cloned upstream of the lux reporter to form the first part of the screening reporter array. random promoter library of salmonella enterica and pseudomonas aeruginosa were screened for antibiotic responsive ...201020353098
inactivation of salmonella enterica and listeria monocytogenes inoculated on hydroponic tomatoes using chlorine dioxide gas.the main objective of this study was to determine survivability of a cocktail of three strains of salmonella enterica (montevideo, javiana, and baildon) and two strains of listeria monocytogenes (lcdc 81-861 and f4244) on hydroponic tomatoes after treatment with chlorine dioxide (clo(2)) gas. an initial concentration of 8-9 log cfu/ml of salmonella and listeria cocktails was inoculated individually, in separate experiments, on tomato skin to obtain a population of 7-8 log cfu/cm(2) after drying ...201020353288
dna microarray analysis of salmonella serotype typhimurium strains causing different symptoms of disease.salmonella enterica subsp. enterica is one of the leading food-borne pathogens in the usa and european countries. outcome of human salmonella serotype typhimurium infections ranges from mild self-limiting diarrhoea to severe diarrhoea that requires hospitalization. increased knowledge of the mechanisms that are responsible for causing infection and especially the severity of infection is of high interest.201020356366
structural insight into the regulatory mechanisms of interactions of the flagellar type iii chaperone flit with its binding partners.for self-assembly of the bacterial flagellum, most of the flagellar component proteins synthesized in the cytoplasm are exported by the flagellar type iii export apparatus to the growing, distal end. flagellar protein export is highly organized and well controlled in every step of the flagellar assembly process. flagellar-specific chaperones not only facilitate the export of their cognate proteins, as well as prevent their premature aggregation in the cytoplasm, but also play a role in fine-tuni ...201020421493
effect of translesion dna polymerases, endonucleases and rpos on mutation rates in salmonella typhimurium.it has been suggested that bacteria have evolved mechanisms to increase their mutation rate in response to various stresses and that the translesion dna polymerase pol iv under control of the lexa regulon and the alternative sigma factor rpos are involved in regulating this mutagenesis. here we examined in salmonella enterica serovar typhimurium lt2 the rates for four different types of mutations (rifampicin, nalidixic acid, and chlorate resistance and lac(+) reversion) during various growth con ...201020421601
detection, amplification & sequence homology of sodc in clinical isolates of salmonella sp.periplasmic copper and zinc superoxide dismutase (cu,zn-sod or sodc) is an important component of the antioxidant shield which protects bacteria from the phagocytic oxidative burst. cu,zn-sods protect gram-negative bacteria against oxygen damage which have also been shown to contribute to the pathogenicity of these bacterial species. we report the presence of sodc in drug resistant salmonella sp. isolated from patients suffering from enteric fever. further sodc was amplified, cloned into escheri ...201020424309
predation of salmonella enterica serovar typhimurium by the rumen protozoon entodinium caudatum studied in vitro by fluorescence emission.predation of bacteria by protozoa has important implications on rumen metabolism and bacterial populations. protozoa can also restrict the passage of pathogenic bacteria to the host's lower gastrointestinal tract. this work aimed to evaluate the predation by entodinium caudatum (ec) and the intraprotozoal survival of salmonella enterica serovar typhimurium. ec cells from a monofaunated sheep were incubated for up to 105 min with a s. enterica strain producing a green fluorescent protein. rumen f ...201020427163
effects of dam and/or seqa mutations on the fatty acid and phospholipid membrane composition of salmonella enterica serovar typhimurium.we examined the phospholipids (phls) and the membrane fatty acid (fa) composition in salmonella enterica serovar typhimurium dam and/or seqa mutants. phosphatidylglycerol, phosphatidylethanolamine (pe), and cardiolipin (cl) are the major phls present in all the strains and accounted for greater than 95% of the total lipid phosphorus. phosphatidic acid and phosphatidylserine are the minor ones. the seqa mutant showed a decrease in pe and an increase in cl and phosphatidylglycerol proportion compa ...201020132031
isolation of salmonella enterica serovar enteritidis in blue-fronted amazon parrot (amazona aestiva).avian salmonellosis is a disease caused by bacteria of the genus salmonella that can cause three distinct diseases in birds: pullorum diseases, fowl typhoid, and paratyphoid infection. various wildlife species are susceptible to infections by salmonella, regardless of whether they live in captivity or freely in the wild. the present study verified the presence of salmonella enterica serovar enteritidis in three captive specimens of amazona aestiva. the study involved a total of 103 birds undergo ...201020408416
cholinergic stimulation of the immune system protects against lethal infection by salmonella enterica serovar typhimurium.summary: the cholinergic nervous system has been demonstrated to attenuate the inflammatory response during sepsis via the inhibitory action of acetylcholine (ach) on macrophages. these findings were largely based on experimental sepsis models using endotoxin as the inducing agent. herein, however, we report that the specific inhibition of acetylcholinesterase (ache) renders animals more resistant to infection by a virulent strain of salmonella enterica serovar typhimurium, a gram-negative enter ...201020408892
evidence for a second genomic island conferring multidrug resistance in a clonal group of strains of salmonella enterica serovar typhimurium and its monophasic variant circulating in italy, denmark, and the united kingdom.during the 2000s, a new clonal group with resistances to ampicillin, streptomycin, sulfonamides, and tetracycline (assut) emerged in italy among strains of salmonella enterica serovar typhimurium and its monophasic variant, salmonella enterica subspecies enterica serovar 4,[5],12:i:-. the pulsenet europe database allowed us to identify assut strains of both s. typhimurium and its monophasic variant, isolated in denmark and the united kingdom, with the same or very closely related pulsed-field ge ...201020410351
a purified mutant hema protein from salmonella enterica serovar typhimurium lacks bound heme and is defective for heme-mediated regulation in vivo.archaea, plants, and most bacteria synthesize heme using the c5 pathway, in which the first committed step is catalyzed by the enzyme glutamyl-trna reductase (glutr or hema). in some cases, an overproduced and purified hema enzyme contains noncovalently bound heme. the enteric bacteria salmonella enterica and escherichia coli also synthesize heme by the c5 pathway, and the hema protein in these bacteria is regulated by proteolysis. the enzyme is unstable during normal growth due to the action of ...201020412302
antimicrobial effect of photodynamic therapy using a highly pure chlorin e6.the aim of the present study is to evaluate the antimicrobial effect of photodynamic therapy (pdt) using a highly pure chlorin e(6) (ce(6)), against various pathogenic bacteria. to examine the antimicrobial effect of ce(6)-mediated pdt against staphylococcus aureus, pseudomonas aeruginosa, escherichia coli, and salmonella enterica serovar typhimurium, inhibition zone formation, cfu quantification, and bacterial viability were evaluated. inhibition zone analysis showed that ce(6)-mediated pdt is ...201020414708
a case report of thrombocytopenia-associated multiple organ failure secondary to salmonella enterica serotype typhi infection in a pediatric patient: successful treatment with plasma exchange.a high proportion of the patients with salmonella enterica serotype typhi infection develop severe sepsis. the mortality rate is high despite aggressive antimicrobial therapy in these patients. the case of a 10-year-old boy who developed thrombocytopenia-associated multiple organ failure (tamof) secondary to s. typhi infection is reported. the patient did not respond to antimicrobial treatment, including ciprofloxacin, in addition to conventional supportive measures, so plasma exchange was perfo ...201020438547
real-time pcr detection of salmonella species using a novel target: the outer membrane porin f gene (ompf).to evaluate the outer membrane porin f gene (ompf) for the specific detection of salmonella species by real-time pcr assay.201020438619
mutations in the lipid a deacylase pagl which release the enzyme from its latency affect the ability of pagl to interact with lipopolysaccharide in salmonella enterica serovar typhimurium.pagl, a lipid a deacylase, is unique in that it is latent in the outer membrane of salmonella enterica serovar typhimurium. several point mutations in the extracellular loops of pagl, which do not affect its enzymatic activity, release it from this latency. precipitation analysis revealed that latent wild-type pagl associated with lipopolysaccharide, but non-latent pagl mutants did not. in contrast, non-latent pagl mutants preferentially associated with some membrane proteins. precipitation anal ...201020438711
serotypes and antimicrobial resistance profiles of salmonella isolates from pigs at slaughter in kenya.salmonellosis is considered one of the most widespread food-borne zoonoses in industrialized as well as developing countries. the presence of salmonella in food animals at slaughter and the consequent cross-contamination of edible carcass tissues present a significant food safety hazard.201020440063
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