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production of phenylacetic acid derivatives and 4-epiradicinol in culture by curvularia lunata.phenylacetic acid derivatives, methyl 2-acetyl-3,5-dihydroxyphenylacetate (1) and methyl 2-acetyl-5-hydroxy-3-methoxyphenylacetate (3); curvulin or ethyl 2-acetyl-3,5-dihydroxyphenylacetate (4), a known metabolite of curvularia siddiqui, and 4-epiradicinol (5) have been isolated from the culture mycelia of curvularia lunata grown on ymg, a medium consisting of yeast, malt extract and glucose. compounds 1, 3 and 4 lack antimicrobial and antioxidant activity, but 4-epiradicinol (5) inhibited the g ...200616884750
age-related clinical and microbiological characteristics of enteric fever in india.a retrospective, hospital-based study at safdarjang hospital, india, was undertaken between january 1999 and december 2003 to estimate age-related epidemiological, clinical and microbiological characteristics in enteric fever cases. a total of 750 blood-culture-proven cases of enteric fever were studied. the majority of cases occurred in children aged 5-12 years and 24.8% of cases were in children up to 5 years of age. salmonella serotypes showed an age-related predilection, with paratyphoid fev ...200616766005
pseudomembranous colitis due to salmonella enterica serotype infantis. 200616767602
oral dna vaccination with the polyprotein gene of infectious bursal disease virus (ibdv) delivered by the attenuated salmonella elicits protective immune responses in chickens.our previous study showed that vaccination with plasmid dna containing infectious bursal disease virus (ibdv) gene which encodes complete polyprotein (vp2/4/3) induced protective immune responses. in this study, we examined the efficacy of an oral dna vaccine carrying the ibdv polyprotein antigen delivered by attenuated salmonella enterica sv. typhimurium (s. typhimurium). the recombinant plasmid pci-vp2/4/3 was transformed by electroporation into an attenuated s.typhimurium strain (dam phop) (d ...200616769159
ciprofloxacin resistance in salmonella enterica serotype typhi/paratyphi and antimicrobial agent quality and bioavailability. 200616772428
a survey of foodborne pathogens in bulk tank milk and raw milk consumption among farm families in pennsylvania.a 2-part study was conducted to determine the risk of exposure to human pathogens from raw milk. the first part of the study focused on determining raw milk consumption habits of dairy producers. a total of 248 dairy producers from 16 counties in pennsylvania were surveyed. overall, 105 (42.3%) of the 248 dairy producers consumed raw milk and 170 (68.5%) of the 248 dairy producers were aware of foodborne pathogens in raw milk. dairy producers who were not aware of foodborne pathogens in raw milk ...200616772561
effects of ractopamine hcl on escherichia coli o157:h7 and salmonella in vitro and on intestinal populations and fecal shedding in experimentally infected sheep and pigs.the effects of the beta-agonist ractopamine, approved for use in finishing swine and cattle to improve carcass quality and performance, were examined on two important foodborne pathogens, escherichia coli o157:h7 and salmonella. ractopamine, administered to sheep before and after oral inoculation with e. coli o157:h7, increased (p < 0.01) fecal shedding and tended to increase (p = 0.08) cecal populations of the challenge strain. pigs receiving ractopamine in the diet and then experimentally infe ...200616775793
fis is required for proper regulation of ssag expression in salmonella enterica serovar typhimurium.salmonella pathogenicity island 2 (spi2) encodes a type iii secretion system (ttss) necessary for bacterial survival and replication in intracellular environment of host cells. spi2 genes are transcribed preferentially after salmonella enters the host cells. transcriptional regulation of ssag encoding the component of spi2-ttss apparatus was studied in vivo and in vitro. fis, one of the major components of bacterial nucleoid, activated the stationary phase-specific expression of ssag when salmon ...200616777370
55 kda outer-membrane protein from short-chain fatty acids exposed salmonella enterica serovar typhi induces apoptosis in macrophages.various pathogens including salmonella species are known to induce apoptosis in host cell types during their infection processes. however, the bacterial components capable of inducing apoptosis have not been fully understood. it is now known that in vivo expression of virulence determinants differ from the expression under in vitro conditions. therefore, in the present study, attempts were made to evaluate the apoptotic potential of outer-membrane protein (omp) from short-chain fatty acids (scfa ...200616779627
emergence of multidrug-resistant salmonella enterica serotype newport in minnesota.we report a concurrent increase in the number of isolates of salmonella enterica serotype newport and the rate of multidrug resistance in s. newport isolates from animal and human populations in minnesota. antimicrobial susceptibility and pulsed-field gel electrophoresis analysis demonstrated heterogeneity of isolates and showed that 1 pulsed-field gel electrophoresis cluster contained most of the multidrug-resistant isolates with a resistance pattern and most class 1 integron isolates, implying ...200616779749
class 1 integrons in dutch salmonella enterica serovar dublin isolates from clinical cases of bovine salmonellosis.fifty-nine salmonella enterica serovar dublin (salmonella dublin) isolates from clinical cases of bovine salmonellosis between 1993 and 2004 were tested for their susceptibility to 15 antimicrobial agents and the presence of class 1 integrons. integrons were further analyzed by conserved segment pcr-rflp. dna sequencing was used to identify the inserted gene cassette. twelve (20.3%) isolates were multidrug-resistant. a combination of resistance against chloramphenicol, streptomycin and sulphonam ...200616781090
the temperature-sensing protein tlpa is repressed by phop and dispensable for virulence of salmonella enterica serovar typhimurium in mice.tlpa is a temperature-sensing, coiled-coil protein, encoded on the pslt virulence plasmid of salmonella enterica serovar typhimurium. tlpa was previously presumed to play a role in the pathogenicity of salmonella. herein we show that tlpa is tightly regulated, differentially expressed in response to environmental and physiological signals, and can be secreted in vitro. expression of tlpa was found to be repressed in modified minimal medium containing limiting concentrations of mg2+ and in the st ...200616782389
characterization of antimicrobial resistance and class 1 and 2 integrons in salmonella enterica isolates from different sources in portugal.the antimicrobial resistance profiles of 1183 salmonella isolates collected during 2002-2003 from several sources (human, food products and environment) were evaluated. the occurrence, distribution and cassette content of class 1 and 2 integrons among the sulphonamide-resistant population, as well as the role of particular clones to the spread of these genetic elements, were investigated.200616782741
occurrence of integrons and antimicrobial resistance genes among salmonella enterica from brazil.to determine the occurrence of antimicrobial resistance genes and role of integrons among 135 antimicrobial-resistant salmonella enterica from brazil.200616782743
isolation of different serovars of salmonella enterica from wild birds in great britain between 1995 and 2003.postmortem examinations were carried out on the carcases of 779 wild birds. salmonellosis was a common cause of death in greenfinches (carduelis chloris), house sparrows (passer domesticus) and chaffinches (fringilla coelebs), and was also responsible for the deaths of other birds such as goldfinches (carduelis carduelis), feral pigeons and different species of gulls. most cases of salmonellosis in finches occurred between january and march, whereas salmonellosis in house sparrows tended to occu ...200616782854
phenotypic and genotypic characterization of salmonella enterica serotype paratyphi b isolates from environmental and human sources in galicia, spain.salmonella serotype paratyphi b isolates obtained from shellfish and human infections in galicia (northwest spain) from 1998 were investigated by different phenotypic and genetic methods to evaluate their systemic or enteric nature. isolates were investigated for d-tartrate fermentation, presence of genes encoding the effector proteins sope1 and avra, pulsed-field gel electrophoresis profile, and antimicrobial susceptibility. systemic variant strains (dt-) were the dominant among the marine envi ...200616786846
circulating gamma delta t cells in response to salmonella enterica serovar enteritidis exposure in chickens.gammadelta t cells are considered crucial to the outcome of various infectious diseases. the present study was undertaken to characterize gammadelta (t-cell receptor 1(+) [tcr1(+)]) t cells phenotypically and functionally in avian immune response. day-old chicks were orally immunized with salmonella enterica serovar enteritidis live vaccine or s. enterica serovar enteritidis wild-type strain and infected using the s. enterica serovar enteritidis wild-type strain on day 44 of life. between days 3 ...200616790770
stabilization of a plasmid coding for a heterologous antigen in salmonella enterica serotype typhi vaccine strain cvd908-htra by using site-specific recombination.a gene cassette incorporating the crs-rsd site-specific recombination system from the salmonella enterica subsp. enterica serovar dublin virulence plasmid improved the inheritance in s. enterica serotype typhi strain cvd908-htra of a multicopy plasmid expression vector. use of this recombination cassette may improve expression of heterologous antigens from multicopy plasmid expression vectors in attenuated bacterial vaccine strains.200616790817
an sopb-mediated immune escape mechanism of salmonella enterica can be subverted to optimize the performance of live attenuated vaccine carrier strains.salmonellae have evolved several mechanisms to evade host clearance. here, we describe the influence on bacterial immune escape of the effector protein sopb, which is translocated into the cytosol through a type iii secretion system. wild-type bacteria, as well as the ssec and aroa attenuated mutants exerted a stronger cytotoxic effect on dendritic cells (dc) than their sopb-deficient derivatives. cells infected with the double ssec sopb, phop sopb and aroa sopb mutants also exhibited higher exp ...200616793312
donor-strand exchange in chaperone-assisted pilus assembly proceeds through a concerted beta strand displacement mechanism.gram-negative pathogens commonly use the chaperone-usher pathway to assemble adhesive multisubunit fibers on their surface. in the periplasm, subunits are stabilized by a chaperone that donates a beta strand to complement the subunits' truncated immunoglobulin-like fold. pilus assembly proceeds through a "donor-strand exchange" (dse) mechanism whereby this complementary beta strand is replaced by the n-terminal extension (nte) of an incoming pilus subunit. using x-ray crystallography and real-ti ...200616793551
a mechanical role for the chemotaxis system in swarming motility.the chemotaxis system, but not chemotaxis, is essential for swarming motility in salmonella enterica serovar typhimurium. mutants in the chemotaxis pathway exhibit fewer and shorter flagella, downregulate class 3 or 'late' motility genes, and appear to be less hydrated when propagated on a surface. we show here that the output of the chemotaxis system, chey approximately p, modulates motor bias during swarming as it does during chemotaxis, but for a distinctly different end. a constitutively act ...200616796690
berry phenolics: antimicrobial properties and mechanisms of action against severe human pathogens.antimicrobial activity and mechanisms of phenolic extracts of 12 nordic berries were studied against selected human pathogenic microbes. the most sensitive bacteria on berry phenolics were helicobacter pylori and bacillus cereus. campylobacter jejuni and candida albicans were inhibited only with phenolic extracts of cloudberry, raspberry, and strawberry, which all were rich in ellagitannins. cloudberry extract gave strong microbicidic effects on the basis of plate count with all studied strains. ...200616800770
functional dissection of ssef, a type iii effector protein involved in positioning the salmonella-containing vacuole.intracellular replication of salmonella enterica requires the formation of a unique organelle termed salmonella-containing vacuole (scv). the type iii secretion system (t3ss) encoded by salmonella pathogenicity island 2 (spi2-t3ss) has a crucial role in the formation and maintenance of the scv. the spi2-t3ss translocates a large number of effector proteins that interfere with host cell functions such as microtubule-dependent transport. we investigated the function of the effector ssef and observ ...200616800847
identification of the lipopolysaccharide modifications controlled by the salmonella pmra/pmrb system mediating resistance to fe(iii) and al(iii).iron is an essential metal but can be toxic in excess. while several homeostatic mechanisms prevent oxygen-dependent killing promoted by fe(ii), little is known about how cells cope with fe(iii), which kills by oxygen-independent means. several gram-negative bacterial species harbour a regulatory system - termed pmra/pmrb - that is activated by and required for resistance to fe(iii). we now report the identification of the pmra-regulated determinants mediating resistance to fe(iii) and al(iii) i ...200616803591
in vivo, flic expression by salmonella enterica serovar typhimurium is heterogeneous, regulated by clpx, and anatomically restricted.flic is a natural antigen recognized by the innate and adaptive immune systems during salmonella infection in mice and humans; however, the regulatory mechanisms governing its expression in vivo are incompletely understood. here, we use flow cytometry to quantify flic gene expression in single bacteria. in vitro, flic transcription was not uniformly positive; a viable flic-negative subpopulation was also identified. intracellular salmonella repressed transcription of flic and its positive regula ...200616803592
distribution of prophages and sgi-1 antibiotic-resistance genes among different salmonella enterica serovar typhimurium isolates.recently, the authors identified salmonella enterica serovar typhimurium (s. typhimurium) definitive type (dt)104-specific sequences of mainly prophage origin by genomic subtractive hybridization. in the present study, the distribution of the prophages identified, st104 and st64b, and the novel prophage remnant designated prophage st104b, was tested among 23 non-dt104 s. typhimurium isolates of different phage types and 19 isolates of the dt104 subtypes dt104a, dt104b low and dt104l, and the dt1 ...200616804187
plasmid-mediated quinolone resistance in non-typhi serotypes of salmonella enterica.serious infections with salmonella species are often treated with fluoroquinolones or extended-spectrum beta-lactams. increasingly recognized in enterobacteriaceae, plasmid-mediated quinolone resistance is encoded by qnr genes. here, we report the presence of qnr variants in human isolates of non-typhi serotypes of salmonella enterica (hereafter referred to as non-typhi salmonella) from the united states national antimicrobial resistance monitoring system for enteric bacteria.200616804843
flagellin in combination with curli fimbriae elicits an immune response in the gastrointestinal epithelial cell line ht-29.flagellin is the major cytokine-releasing factor when salmonella enterica serovar typhimurium (s. typhimurium) infects intestinal epithelial cells. in this work it is shown that curli, an adhesive proteinaceous surface component of enterobacteriaceae involved in biofilm formation of s. typhimurium and escherichia coli strains can bind flagellin and thus elicit an immune response by the intestinal epithelial cell line ht-29.200616807036
differentiation of selected salmonella enterica serovars by fourier transform mid-infrared spectroscopy.salmonella enterica serovars include pathogens responsible for high numbers of foodborne salmonellosis. fourier transform infrared (ft-ir) spectroscopy can be used to rapidly and accurately identify microorganisms based on unique spectra of bacterial cell components. the objectives of this study were to discriminate closely related salmonella enterica serovars by using ft-ir spectroscopy and multivariate analysis and to compare the performance of three techniques for differentiating among salmon ...200616808859
long polar fimbriae and tissue tropism in escherichia coli o157:h7.in vitro organ culture has demonstrated the human intestinal tropism of enterohaemorrhagic escherichia coli o157:h7 for follicle associated epithelium overlying peyer's patches of the terminal ileum. long polar (lp) fimbriae are considered to mediate the attachment of salmonella enterica serovar typhimurium to peyer's patch epithelium and, as homologous genes have been identified in o157:h7, we hypothesised that lp fimbriae in o157:h7 may perform the same function. however, mutation of lp fimbri ...200616815722
protection of neonatal mice from lethal enterovirus 71 infection by maternal immunization with attenuated salmonella enterica serovar typhimurium expressing vp1 of enterovirus 71.this study describes the potential use of attenuated salmonella enterica serovar typhimurium strains to express and deliver vp1 of enterovirus 71 (ev71) as a vaccination strategy to prevent ev71 infection in mice. when orally administered to balb/c mice, both attenuated carrier strains, cnp101 and sl7207, were able to efficiently invade livers and spleens, while only the virulence plasmid-carrying strain sl7207 persisted for more than 30 days in these organs. a recombinant in vivo-regulated prom ...200616815726
limited role for the dsra and rpra regulatory rnas in rpos regulation in salmonella enterica.rpos, the sigma factor of enteric bacteria that responds to stress and stationary phase, is subject to complex regulation acting at multiple levels, including transcription, translation, and proteolysis. increased translation of rpos mrna during growth at low temperature, after osmotic challenge, or with a constitutively activated rcs phosphorelay depends on two trans-acting small regulatory rnas (srnas) in escherichia coli. the dsra and rpra srnas are both highly conserved in salmonella enteric ...200616816180
sigma28-dependent transcription in salmonella enterica is independent of flagellar shearing.the flgm anti-sigma28 factor is secreted in response to flagellar hook-basal body completion to allow sigma28-dependent transcription of genes needed late in flagellar assembly, such as the flagellin structural gene, flic. a long-standing hypothesis was that one role of flgm secretion was to allow rapid expression of flagellin in response to shearing. we tested this hypothesis by following flgm secretion and flic transcription in response to flagellar shearing. experiments showed that the level ...200616816191
osmotic upshift transiently inhibits uptake via abc transporters in gram-negative bacteria.atp-binding cassette transporters from several rhizobia and salmonella enterica serovar typhimurium, but not secondarily coupled systems, were inhibited by high concentrations (100 to 500 mm) of various osmolytes, an effect reversed by the removal of the osmolyte. abc systems were also inactivated in isolated pea bacteroids, probably due to the obligatory use of high-osmolarity isolation media. measurement of nutrient cycling in isolated pea bacteroids is impeded by this effect.200616816205
identification of the proteasome inhibitor mg262 as a potent atp-dependent inhibitor of the salmonella enterica serovar typhimurium lon protease.lon is a homo-oligomeric atp-dependent serine protease which functions in the degradation of damaged and certain regulatory proteins. the importance of lon activity in bacterial pathogenicity has led to its emergence as a target in the development of novel antibiotics. as no potent inhibitors of lon activity have been reported to date, we sought to identify an inhibitor which could serve as a lead compound in the development of a potent lon-specific inhibitor. to determine whether a nucleotide- ...200616819825
comparison of the concentrations of phenolic compounds in olive oils and other plant oils: correlation with antimicrobial activity.the antimicrobial activity of different edible vegetable oils was studied. in vitro results revealed that the oils from olive fruits had a strong bactericidal action against a broad spectrum of microorganisms, this effect being higher in general against gram-positive than gram-negative bacteria. thus, olive oils showed bactericidal activity not only against harmful bacteria of the intestinal microbiota (clostridium perfringens and escherichia coli) also against beneficial microorganisms such as ...200616819902
phylogenetic relationships among clonal groups of extraintestinal pathogenic escherichia coli as assessed by multi-locus sequence analysis.the evolutionary origins of extraintestinal pathogenic escherichia coli (expec) remain uncertain despite these organisms' relevance to human disease. a valid understanding of expec phylogeny is needed as a framework against which the observed distribution of virulence factors and clinical associations can be analyzed. accordingly, phylogenetic relationships were defined by multi-locus sequence analysis among 44 representatives of selected expec clonal groups and the e. coli reference (ecor) coll ...200616820314
generating tetracycline-inducible auxotrophy in escherichia coli and salmonella enterica serovar typhimurium by using an insertion element and a hyperactive transposase.we report the construction and application of a novel insertion element for transposase-mediated mutagenesis in gram-negative bacteria. besides km(r) as a selectable marker, the insertion element instet(g-)1 carries the anhydrotetracycline (atc)-regulated outward-directed pa promoter so that atc-dependent conditional gene knockouts or knockdowns are generated. the complex formed between the purified hyperactive transposase and instet(g-)1 was electroporated into escherichia coli or salmonella en ...200616820464
alteration of the rugose phenotype in waag and ddhc mutants of salmonella enterica serovar typhimurium dt104 is associated with inverse production of curli and cellulose.the rugose (also known as wrinkled or rdar) phenotype in salmonella enterica serovar typhimurium dt104 rv has been associated with cell aggregation and the ability, at low temperature under low-osmolarity conditions, to form pellicles and biofilms. two tn5 insertion mutations in genes that are involved in lipopolysaccharide (lps) synthesis, ddhc (a1-8) and waag (a1-9), of rv resulted in diminished expression of colony rugosity. scanning electron micrographs revealed that the ddhc mutant showed r ...200616820499
molecular cloning and characterization of a large subunit of salmonella typhimurium glutamate synthase (gogat) gene in escherichia coli.two pathways of ammonium assimilation and glutamate biosynthesis have been identified in microorganisms. one pathway involves the nadp-linked glutamate dehydrogenase, which catalyzes the amination of 2-oxoglutarate to form glutamate. an alternative pathway involves the combined activities of glutamine synthetase, which aminates glutamate to form glutamine, and glutamate synthase, which transfers the amide group of glutamine to 2-oxoglutarate to yield two molecules of glutamate. we have cloned th ...200616820760
comparison of antagonistic ability against enteropathogens by g+ and g- anaerobic dominant components of human fecal microbiota.to confirm if anaerobic g+-components are those responsible for the function of colonization resistance, obligate anaerobic g+- and g- -bacteria from normal dominant microbiota of human feces were isolated from three successive collections and then used in in vitro assays for antagonism against two enteropathogenic bacteria. the production of inhibitory diffusible compounds was determined on supplemented bhi agar and mrs agar media for g- - and g+-bacteria, respectively. salmonella enterica subs ...200616821725
the o-antigen affects replication of salmonella enterica serovar typhimurium in murine macrophage-like j774-a.1 cells through modulation of host cell nitric oxide production.o-antigen-proficient and defined o-antigen-deficient mutants of salmonella enterica serovar typhimurium were compared for intracellular replication and induction of nitric oxide (no) expression in the murine macrophage-like cell line j774-a.1. while o-antigen-proficient bacteria replicated and provoked induction of host cell no synthesis to expected levels, deltawaak, deltawaal and deltawaakl mutants displayed increased growth yields and induction of significantly lower levels of macrophage no p ...200616822688
caspase-1-dependent pore formation during pyroptosis leads to osmotic lysis of infected host macrophages.salmonella enterica serovar typhimurium invades host macrophages and induces a unique caspase-1-dependent pathway of cell death termed pyroptosis, which is activated during bacterial infection in vivo. we demonstrate dna cleavage during pyroptosis results from caspase-1-stimulated nuclease activity. although poly(adp-ribose) polymerase (parp) activation by fragmented dna depletes cellular atp to cause lysis during oncosis, the rapid lysis characteristic of salmonella-infected macrophages does no ...200616824040
safety and immunogenicity of attenuated salmonella enterica serovar typhimurium delivering an hiv-1 gag antigen via the salmonella type iii secretion system.cks257 (salmonella typhimurium sl1344 deltaphop/phoqdelta aroa deltaasd deltastra/strb psb2131) is a live oral vaccine vector expressing hiv gag.200616824652
detection of multidrug-resistant salmonella enterica serovar typhimurium phage types dt102, dt104, and u302 by multiplex pcr.salmonella enterica serovar typhimurium is a common cause of nontyphoidal salmonellosis in humans and animals. multidrug-resistant serovar typhimurium phage type dt104, which emerged in the 1990s, has become widely distributed in many countries. a total of 104 clinical isolates of salmonella serogroup b were collected from three major hospitals in taiwan during 1997 to 2003 and were examined by a multiplex pcr targeting the resistance genes and the spv gene of the virulence plasmid. a total of 5 ...200616825349
comparison of multilocus sequence typing, pulsed-field gel electrophoresis, and antimicrobial susceptibility typing for characterization of salmonella enterica serotype newport isolates.in the united states, multidrug-resistant phenotypes of salmonella enterica serotype newport (commonly referred to as mdr-ampc) have emerged in animals and humans and have become a major public health problem. although pulsed-field gel electrophoresis (pfge) is the current "gold standard" typing method for salmonella, multilocus sequence typing (mlst) may be more relevant to investigations exploring evolutionary and population biology relationships. in this study, 81 salmonella enterica serotype ...200616825363
molecular typing reveals a unique clone of salmonella enterica serotype typhi among indian strains. 200616825414
coordinated regulation of two independent cell-cell signaling systems and swarmer differentiation in salmonella enterica serovar typhimurium.almost all members of the genus salmonella differentiate and migrate on semisolid surfaces in a coordinated population behavior known as swarming. important virulence determinants are coupled to swarmer differentiation in several other pathogenic organisms, collectively suggesting that conditions that trigger swarming in the laboratory may fortuitously promote the cells to enter a robust physiological state relevant to the host environment. here, we present evidence that expression of two indepe ...200616385032
the beta-oxidation systems of escherichia coli and salmonella enterica are not functionally equivalent.based on its genome sequence, the pathway of beta-oxidative fatty acid degradation in salmonella enterica serovar typhimurium lt2 has been thought to be identical to the well-characterized escherichia coli k-12 system. we report that wild-type strains of s. enterica grow on decanoic acid, whereas wild-type e. coli strains cannot. mutant strains (carrying fadr) of both organisms in which the genes of fatty acid degradation (fad) are expressed constitutively are readily isolated. the s. enterica f ...200616385050
low tyrosine content of growth media yields aflagellate salmonella enterica serovar typhimurium.identification of salmonella serotypes is based on flagellar and somatic antigens. the absence of flagella may consequently affect complete identification of the serotype; here it is shown that salmonella enterica serovar typhimurium exhibits morphological differences dependent on the peptone constituents of the culture medium. aflagellate salmonella were produced in certain media where the nutritional ingredient was casein-based peptone or gelatin-based peptone; in gelatin-based peptone, aggreg ...200616385112
plasmid-mediated high-level gentamicin resistance among enteric bacteria isolated from pet turtles in louisiana.the sale of small turtles is banned by the food and drug administration from the u.s. market due to concerns about their excretion of salmonella spp. to produce a safe pet for the export market, the louisiana pet turtle industry uses gentamicin sulfate baths (1,000 microg/ml) to eradicate salmonella spp. from turtle eggs. in 1999, we analyzed bacterial samples recovered from turtle farms and found that strains of salmonella enterica subsp. arizonae and other bacteria, such as enterobacter cloaca ...200616391058
butyrate specifically down-regulates salmonella pathogenicity island 1 gene expression.invasion of intestinal epithelial cells by salmonella enterica is decreased after exposure to butyric acid. to understand the molecular mechanisms of this phenomenon, a comparative transcriptomic analysis of salmonella enterica serovar enteritidis and salmonella enterica serovar typhimurium grown in medium supplemented with butyrate was performed. we found that butyrate down-regulated the expression of 19 genes common to both serovars by a factor of twofold or more, and 17 of these genes localiz ...200616391141
[salmonella infections acquired from exotic pets].the majority of non-typhoidal salmonella infections are foodborne, with undercooked eggs, chicken and red meat being the most important sources. transmission from exotic pets, reptiles in particular, may account for 3-5% of human salmonella cases. we describe a case of s. saintpaul infection in an eight-month-old infant. a food source was unlikely because the infant was fed from a percutaneous endoscopic gastrostomy tube and the food tested negative for salmonella. the family kept pet turtles, a ...200616393568
pspb and pspc of yersinia enterocolitica are dual function proteins: regulators and effectors of the phage-shock-protein response.the phage-shock-protein (psp) stress-response system is conserved in many bacteria and has been linked to important phenotypes in escherichia coli, salmonella enterica and also yersinia enterocolitica, where it is essential for virulence. it is activated by specific extracytoplasmic stress events such as the mislocalization of secretin proteins. from studies of the psp system in e. coli, the cytoplasmic membrane proteins pspb and pspc have only been proposed to act as positive regulators of psp ...200616468999
osmoprotection of salmonella enterica serovar typhimurium by ngamma-acetyldiaminobutyrate, the precursor of the compatible solute ectoine.n(gamma)-acetyl-2,4-diaminobutyrate (nada), the precursor of the compatible solute ectoine, was shown to function as an osmoprotectant for the non-halophilic bacterium salmonella enterica serovar typhimurium. the addition of nada-containing extracts of an ectoine synthase mutant of the broad salt-growing halophile chromohalobacter salexigens dsm 3043(t) could alleviate the inhibitory effects of high salinity in s. enterica, which lacks the ectoine biosynthetic pathway. nada, purified from extrac ...200616469465
distinctive mass losses of tryptic peptides generated by matrix-assisted laser desorption/ionization time-of-flight/time-of-flight. 200616470705
effects of salmonella enterica serovars typhimurium (st) and choleraesuis (sc) on chemokine and cytokine expression in swine ileum and jejunal epithelial cells.the gastrointestinal epithelium represents a barrier to potentially invasive enteric pathogens, maintains a role in innate immune surveillance, and is a source of both chemokine and cytokine chemotactic mediators in response to bacterial invasion. in the current study, we evaluated cytokine and chemokine mediators known to regulate movement of macrophages (macrophage migration inhibitory factor; mif), neutrophils (il8), dendritic cells (ccl20), and epithelial remodeling (osteopontin; opn) in res ...200616473412
monoclonal antibodies binding to the cell surface of listeria monocytogenes serotype 4b.serotype 4b strains of the food-borne pathogen listeria monocytogenes are responsible for a large portion of sporadic listeric infections and all major food-borne listeriosis outbreaks in humans. hybridomas were produced from three fusions with lymphocytes of nd4 mice immunized either with the insoluble antigens of l. monocytogenes serotype 4b or with formalin-killed bacterial cells and screened for monoclonal antibodies (mabs) reactive to l. monocytogenes serotype 4b. a set of 35 mabs was ident ...200616476793
outbreak of multidrug-resistant salmonella enterica serotype typhimurium definitive type 104 infection linked to commercial ground beef, northeastern united states, 2003-2004.multidrug-resistant salmonella enterica serotype typhimurium definitive type 104 (dt104) emerged in the 1990s and is associated with greater clinical severity than pansusceptible s. typhimurium. although infection with dt104 is common in the united states, it is rarely associated with outbreaks. from october to december 2003, a cluster of dt104 infections with indistinguishable pulsed-field gel electrophoresis patterns was identified in the northeastern united states.200616477547
evaluation of bacterial and protozoal contamination of commercially available raw meat diets for dogs.to evaluate bacterial and protozoal contamination of commercially available raw meat diets for dogs.200616478425
long-term persistence of multi-drug-resistant salmonella enterica serovar newport in two dairy herds.to evaluate the association between maintaining joint hospital and maternity pens and persistence of multi-drug-resistant (mdr) salmonella enterica serovar newport on 2 dairy farms.200616478439
differentiation of outer membrane proteins from salmonellaenterica serotypes using fourier transform infrared spectroscopy and chemometrics.to differentiate between outer membrane proteins (omps) from six salmonellaenterica serotypes using a fourier transform infrared (ftir) spectroscopy method and chemometrics.200616478509
regulation of bacterial virulence by two-component systems.in bacteria, two-component systems (tcs) are widely used signal transduction devices which are engaged in a multitude of gene regulatory systems that respond to changing growth conditions. many pathogenic bacteria encounter different microenvironments during their infectious cycle and their ability to efficiently adapt to different niches inside and outside of their host organisms is frequently mediated by tcss, which can, therefore, be considered as an essential prerequisite for their pathogeni ...200616481212
development of an indirect enzyme-linked immunosorbent assay for detecting equine serum antibodies to the lipopolysaccharide of salmonella abortusequi.an indirect enzyme-linked immunosorbent assay (ielisa) was developed for the detection of equine serum antibodies to lipopolysaccharide of salmonella enterica subsp. enterica serovar abortusequi (lps), a causative organism of equine paratyphoid. the data presented demonstrates that horses immunized with s. abortusequi lps developed antibodies detectable by the ielisa. by comparison, the tube agglutination test (tat) did not detect antibody to s. abortusequi lps as consistently as the ielisa. the ...200616483621
plasmid-mediated high-level ceftriaxone resistance in a salmonella enterica serotype typhimurium isolate.to present the first documented case of acute infectious gastroenteritis caused by high-level ceftriaxone-resistant salmonella enterica serotype typhimurium in kuwait.200616484843
[27-year-old man with high fever and septic shock after returning from vacation].a 27-year-old man was admitted with high fever and shivers eleven days after returning from vacation in indonesia. physical examination, laboratory values, abdominal ultrasound, and chest x-ray were not conclusive. all blood cultures yielded growth of salmonella enterica serovar typhi, and typhoid fever was diagnosed. subsequently, the patient developed septic shock and pulmonary edema. in this case report epidemiological, clinical, and therapeutic aspects of typhoid fever are discussed with spe ...200616485096
the cotranscribed salmonella enterica sv. typhi tsx and impx genes encode opposing nucleoside-specific import and export proteins.the salmonella enterica tsx gene encodes a nucleoside-specific outer membrane channel. the tsx porin is essential for the prototrophic growth of s. enterica sv. typhi in the absence of nucleosides. rt-pcr analysis shows that the tsx gene is cotranscribed with an open reading frame unique to s. enterica, impx (sty0450), which encodes an inner membrane protein 108 amino acids in length, which is predicted to have only two transmembrane alpha-helices. fusions of the lacz gene to both tsx and impx r ...200616489221
emergence of multidrug-resistant salmonella enterica serotype typhi with decreased ciprofloxacin susceptibility in bangladesh.during 1989-2002, we studied the antimicrobial resistance of 3928 blood culture isolates of salmonella enterica serotype typhi (s. typhi) in dhaka, bangladesh. overall 32% (1270) of the strains were multidrug-resistant (mdr, resistant to chloramphenicol, ampicillin and trimethoprim-sulphamethoxazole); first detected in 1990 (rate of 8%), increased in 1994 (44%), declined in 1996 (22%, p<0.01 compared to 1994) and re-emerged in 2001 (36%) and 2002 (42%, p<0.01 compared to 1996). an increased mic ...200616490150
overexpression of mara, soxs and acrb in veterinary isolates of salmonella enterica rarely correlates with cyclohexane tolerance.to determine the contribution of the acrab efflux system to cyclohexane tolerance in salmonella enterica.200616492722
autophagy controls salmonella infection in response to damage to the salmonella-containing vacuole.salmonella enterica serovar typhimurium (s. typhimurium) is a facultative intracellular pathogen that causes disease in a variety of hosts. s. typhimurium actively invade host cells and typically reside within a membrane-bound compartment called the salmonella-containing vacuole (scv). the bacteria modify the fate of the scv using two independent type iii secretion systems (ttss). ttss are known to damage eukaryotic cell membranes and s. typhimurium has been suggested to damage the scv using its ...200616495224
the outer core lipopolysaccharide of salmonella enterica serovar typhi is required for bacterial entry into epithelial cells.salmonella enterica serovar typhi causes typhoid fever in humans. central to the pathogenicity of serovar typhi is its capacity to invade intestinal epithelial cells. the role of lipopolysaccharide (lps) in the invasion process of serovar typhi is unclear. in this work, we constructed a series of mutants with defined deletions in genes for the synthesis and polymerization of the o antigen (wbap, wzy, and wzz) and the assembly of the outer core (waak, waaj, waai, waab, and waag). the abilities of ...200616495526
salmonella enterica highly expressed genes are disease specific.during in vitro broth culture, bacterial gene expression is typically dominated by highly expressed factors involved in protein biosynthesis, maturation, and folding, but it is unclear if this also applies to conditions in natural environments. here, we used a promoter trap strategy with an unstable green fluorescent protein reporter that can be detected in infected mouse tissues to identify 21 salmonella enterica promoters with high levels of activity in a mouse enteritis model. we then measure ...200616495536
induction of a novel chicken toll-like receptor following salmonella enterica serovar typhimurium infection.toll-like receptors (tlrs) are a group of highly conserved molecules that initiate the innate immune response to pathogens by recognizing structural motifs expressed by microbes. we have identified a novel tlr, tlr15, by bioinformatic analysis of the chicken genome, which is distinct from any known vertebrate tlr and thus appears to be avian specific. the gene for tlr15 was sequenced and is found on chromosome 3, and it has archetypal tir and transmembrane domains and a distinctive arrangement o ...200616495540
hypophysectomy and neurointermediate pituitary lobectomy reduce serum immunoglobulin m (igm) and igg and intestinal iga responses to salmonella enterica serovar typhimurium infection in rats.the influence of anterior pituitary hormones on the gastrointestinal tract of humans and animals has been reported. hypophysectomy (hypox) in the rat causes atrophy of the intestinal mucosa, reduction of gastric secretion and intestinal absorption, and increased susceptibility to infections. to our knowledge, there are no studies on the humoral immune response of the gut-associated lymphoid tissue after hypox. we have reported that decreased secretion of vasopressin and oxytocin due to neurointe ...200616495563
characterization of salmonella isolated in okinawa, japan.salmonella enterica strains isolated in okinawa between 1995 and 2005 were analyzed with respect to their serovars and antimicrobial susceptibility, and pulsed-field gel electrophoresis (pfge) was used to examine their digestion patterns. a total of 1,071 isolates, including 610 from humans, 358 from animal rectal swabs and 103 from meat obtained at grocery stores, were examined. the first 3 most frequent serovars in human isolates were enteritidis, weltevreden and bareilly, together accounting ...200616495628
characterization of the outbreak-derived salmonella enterica serovar enteritidis strains with atypical triple sugar iron and simmons citrate reactions. 200616495642
multistate outbreak of salmonella typhimurium infections associated with eating ground beef--united states, 2004.salmonella infections cause an estimated 1.4 million human illnesses and 400 deaths annually in the united states. although the incidence of several other foodborne bacterial infections decreased substantially during 1996-2004, the incidence of salmonella infections declined modestly. in september 2004, the new mexico department of health received reports from the new mexico scientific laboratory division of eight salmonella enterica serotype typhimurium isolates that had indistinguishable pulse ...200616498383
serotype distribution and antimicrobial resistance of salmonella enterica from patients with gastroenteritis in crete, greece.the aim of the present study was to determine the serotype distribution and the evolution of antimicrobial resistance among salmonella enterica strains isolated from patients with diarrhea in crete, greece, during a 5-year period (2000-2004). among the 401 s. enterica isolates recovered, serotype enteritidis was the most prevalent (66.6%), followed by serotype typhimurium (14.2%). the rates of resistance to ampicillin, amoxicillin-clavulanic acid, gentamicin, chloramphenicol, tetracycline, nalid ...200616498523
high-level resistance to mecillinam produced by inactivation of soluble lytic transglycosylase in salmonella enterica serovar typhimurium.by screening for high-level mecillinam resistant derivatives of a low-level resistant strain (cysb403 gale1922 rela21::tn10) of salmonella enterica serovar typhimurium, a mudj insertion in the gene for soluble lytic transglycosylase (slt) was isolated. this insertion (slt-1::mudj) increased the resistance to mecillinam of cysb and cyse strains (mic: about 20-40 microg ml(-1)) to a strikingly high level (mic: 160 microg ml(-1)). as in escherichia coli k-12, the slt mutation slightly increased the ...200616499622
functional annotation and kinetic characterization of phno from salmonella enterica.phosphorus is an essential nutrient for all living organisms. under conditions of inorganic phosphate starvation, genes from the pho regulon are induced, allowing microorganisms to use phosphonates as a source of phosphorus. the phno gene was previously annotated as a transcriptional regulator of unknown function due to sequence homology with members of the gcn5-related n-acyltransferase family (gnat). phno can now be functionally annotated as an aminoalkylphosphonic acid n-acetyltransferase whi ...200616503658
typhoid fever as a cause of opportunistic infection: case report.typhoid fever is a systemic infection caused by the bacterium salmonella enterica subspecies enterica serotype typhi, which is acquired by ingestion of contaminated food and water. each year the disease affects at least 16 million persons world-wide, most of whom reside in the developing countries of southeast asia and africa. in italy the disease is uncommon with a greater number of cases in southern regions than in northern ones.200616504150
changing trends in the antibiograms of salmonella isolates at a tertiary care hospital in hyderabad.the present study was undertaken to compare the changing trends of antibiograms of salmonella enterica serovar typhi and salmonella enterica serovar paratyphi a isolates. a total of 80 isolates of salmonella obtained from blood cultures between 2001-2004 were included in the study. identification and antibiotic sensitivities of the isolates were performed by using mini api (bio merieux, france). sixty isolates were identified as salmonella enterica serovar typhi and 20 were identified as salmone ...200616505555
kmra multidrug efflux pump from klebsiella pneumoniae.we cloned a gene responsible for multidrug resistance from the chromosomal dna of klebsiella pneumoniae mgh78578 that showed multidrug resistance. we designated the gene kmra. the deduced amino acid sequence of kmra was similar to that of smva that is responsible for methyl viologen-resistance in salmonella enterica sv. typhi and typhimurium. introduction of the cloned kmra gene into drug-hypersensitive escherichia coli kam32 cells made them resistant to acriflavine, 4',6-diamidino-2-phenylindol ...200616508165
cell-mediated and humoral immune responses to a virulent plasmid-cured mutant strain of salmonella enterica serotype gallinarum in broiler chickens.one-week-old salmonella-free broiler chicks were subcutaneously immunized and subsequently boosted two weeks later with 2x10(7)cfu 0.5ml(-1) of an 85-kb virulent plasmid-cured spectinomycin-resistant mutant strain (sg9vp(-)spc(r)) of salmonella gallinarum 9 (s. enterica serotype gallinarum 9) along with a control group of mock-immunized chickens. the chicks were subcutaneously challenged at 5 weeks of age with 5x10(10)cfu 0.5ml(-1) (5xld(50)) of wild-type s. gallinarum var. duisburg (s. enterica ...200616510254
identification of new flagellar genes of salmonella enterica serovar typhimurium.rna levels of flagellar genes in eight different genetic backgrounds were compared to that of the wild type by dna microarray analysis. cluster analysis identified new, potential flagellar genes, three putative methyl-accepting chemotaxis proteins, stm3138 (mcpa), stm3152 (mcpb), and stm3216(mcpc), and a chev homolog, stm2314, in salmonella, that are not found in escherichia coli. isolation and characterization of mud-lac insertions in chev, mcpb, mcpc, and the previously uncharacterized aer loc ...200616513753
a sitabcd homologue from an avian pathogenic escherichia coli strain mediates transport of iron and manganese and resistance to hydrogen peroxide.an operon encoding a member of the family of atp-binding cassette (abc) divalent metal ion transporters, homologous to salmonella enterica sitabcd, has been identified in the avian pathogenic escherichia coli (apec) strain chi7122. the sitabcd genes were located on the virulence plasmid papec-1, and were highly similar at the nucleotide level to the chromosomally encoded sitabcd genes present in shigella spp. a cloned copy of sitabcd conferred increased growth upon a siderophore-deficient e. col ...200616514154
survival and transmission of salmonella enterica serovar typhimurium in an outdoor organic pig farming environment.it was investigated how organic rearing conditions influence the salmonella enterica infection dynamics in pigs and whether salmonella persists in the paddock environment. pigs inoculated with s. enterica serovar typhimurium were grouped with salmonella-negative tracer pigs. bacteriological and serological testing indicated that organic pigs were susceptible to salmonella infections, as 26 of 46 (56%) tracer pigs turned culture positive. an intermittent and mainly low-level excretion of salmonel ...200616517629
selective removal of dna from dead cells of mixed bacterial communities by use of ethidium monoazide.the distinction between viable and dead bacterial cells poses a major challenge in microbial diagnostics. due to the persistence of dna in the environment after cells have lost viability, dna-based quantification methods overestimate the number of viable cells in mixed populations or even lead to false-positive results in the absence of viable cells. on the other hand, rna-based diagnostic methods, which circumvent this problem, are technically demanding and suffer from some drawbacks. a promisi ...200616517648
multidrug resistance in salmonella enterica serotype typhimurium from humans in france (1993 to 2003).the aim of this study was to determine the distribution of the antimicrobial resistance phenotypes (r types), the phage types and xbai-pulsed-field gel electrophoresis (pfge) types, the genes coding for resistance to beta-lactams and to quinolones, and the class 1 integrons among a representative sample of salmonella enterica serotype typhimurium isolates collected from humans in 2002 through the french national reference center for salmonella (nrc-salm) network. the trends in the evolution of a ...200616517842
genome-wide screen for salmonella genes required for long-term systemic infection of the mouse.a microarray-based negative selection screen was performed to identify salmonella enterica serovar typhimurium (serovar typhimurium) genes that contribute to long-term systemic infection in 129x1/svj (nramp1(r)) mice. a high-complexity transposon-mutagenized library was used to infect mice intraperitoneally, and the selective disappearance of mutants was monitored after 7, 14, 21, and 28 d postinfection. one hundred and eighteen genes were identified to contribute to serovar typhimurium infectio ...200616518469
comparative study of antibacterial resistance among clinical isolates of salmonella enterica non-typhi serotypes in southern bulgaria during 1997-1999 and 2002-2004. 200616528539
the escherichia coli bara-uvry two-component system is a virulence determinant in the urinary tract.the salmonella enterica bara-sira, the erwinia carotovora exps-expa, the vibrio cholerae bara-vara and the pseudomonas spp gacs-gaca all belong to the same orthologous family of two-component systems as the escherichia coli bara-uvry. in the first four species it has been demonstrated that disruption of this two-component system leads to a clear reduction in virulence of the bacteria. our aim was to determine if the escherichia coli bara-uvry two-component system is connected with virulence usin ...200616529647
multidrug resistance among different serotypes of clinical salmonella isolates in taiwan.of the 798 clinical salmonella isolates collected from multiple hospitals in taiwan, resistance to ampicillin (48.5%), chloramphenicol (55.3%), streptomycin (59.0%), sulfamethoxazole (68.0%), and tetracycline (67.8%) was high, whereas resistance to all 5 antimicrobials (acssut r-type) comprised 327 (41%) and was highly prevalent in salmonella enterica serotype typhimurium (72.7%, 176/242), the most common serotype. additional resistance to trimethoprim was present in 155 (19.4% overall) of the a ...200616529903
enterobacterial repetitive intergenic consensus (eric) sequences in escherichia coli: evolution and implications for eric-pcr.enterobacterial repetitive intergenic consensus (eric) sequences are 127-bp imperfect palindromes that occur in multiple copies in the genomes of enteric bacteria and vibrios. here we investigate the distribution of these elements in the complete genome sequences of nine escherichia coli (including shigella species) strains. there is a significant tendency for copies to be adjacent to more highly expressed genes. there is considerable variation among strains with respect to the presence of an el ...200616533821
detection of virulence determinants in clinical strains of salmonella enterica serovar enteritidis and mapping on macrorestriction profiles.a total of 80 strains of salmonella enterica serovar enteritidis, causing gastroenteritis (g) or bacteraemia (b), and three control strains (c), were subjected to: (i) detection of 14 chromosomally and 1 plasmid-located virulence genes by pcr, (ii) detection of dna polymorphisms by xbai and blni pfge, and cluster analysis, (iii) mapping of the 15 screened sequences on macrorestriction profiles and (iv) comparison of the screening and mapping results with data available for other salmonella strai ...200616533982
antibiotic resistance among salmonella enterica isolates in southern european children hospitalized for acute diarrhea. 200616534590
robust salmonella metabolism limits possibilities for new antimicrobials.new antibiotics are urgently needed to control infectious diseases. metabolic enzymes could represent attractive targets for such antibiotics, but in vivo target validation is largely lacking. here we have obtained in vivo information about over 700 salmonella enterica enzymes from network analysis of mutant phenotypes, genome comparisons and salmonella proteomes from infected mice. over 400 of these enzymes are non-essential for salmonella virulence, reflecting extensive metabolic redundancies ...200616541065
inactivation of escherichia coli o157:h7, salmonella typhimurium dt104, and listeria monocytogenes on inoculated alfalfa seeds with a fatty acid-based sanitizer.alfalfa seeds were inoculated with a three-strain cocktail of escherichia coli o157:h7, salmonella enterica subsp. enterica serovar typhimurium dt104, or listeria monocytogenes by immersion to contain approximately 6 to 8 log cfu/g and then treated with a fatty acid-based sanitizer containing 250 ppm of peroxyacid, 1,000 ppm of caprylic and capric acids (emery 658), 1,000 ppm of lactic acid, and 500 ppm of glycerol monolaurate at a reference concentration of 1x. inoculated seeds were immersed at ...200616541689
reduction of salmonella enterica serovar enteritidis on the surface of raw shelled almonds by exposure to steam.this study was conducted to investigate the effect of steam treatment on the reduction of salmonella enterica serovar enteritidis on the surface of raw almonds. two cultivars, 'nonpareil' and 'mission', were studied. salmonella enteritidis was inoculated on the surface of raw almonds, which were then treated with steam (93 degrees c +/- 1 degrees c) for 5, 15, 25, 35, 45, 55, and 65 s. after steam treatment, samples were plated on xylose lysine desoxycholate (xld) and overlay (ov) xld as a selec ...200616541690
the first 45 amino acids of sopa are necessary for invb binding and spi-1 secretion.salmonella enterica serovar typhimurium encodes two type iii secretion systems (ttsss) within pathogenicity island 1 (spi-1) and island 2 (spi-2). these type iii protein secretion and translocation systems transport a panel of bacterial effector proteins across both the bacterial and the host cell membranes to promote bacterial entry and subsequent survival inside host cells. effector proteins contain secretion and translocation signals that are often located at their n termini. we have develope ...200616547027
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