Publications

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 ...	2006	16766005
pseudomembranous colitis due to salmonella enterica serotype infantis.		2006	16767602
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 ...	2006	16769159
ciprofloxacin resistance in salmonella enterica serotype typhi/paratyphi and antimicrobial agent quality and bioavailability.		2006	16772428
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 ...	2006	16772561
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 ...	2006	16775793
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 ...	2006	16777370
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 ...	2006	16779627
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 ...	2006	16779749
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 ...	2006	16781090
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 ...	2006	16782389
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.	2006	16782741
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.	2006	16782743
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 ...	2006	16782854
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 ...	2006	16786846
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 ...	2006	16790770
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.	2006	16790817
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 ...	2006	16793312
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 ...	2006	16793551
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 ...	2006	16796690
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. ...	2006	16800770
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 ...	2006	16800847
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 ...	2006	16803591
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 ...	2006	16803592
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 ...	2006	16804187
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.	2006	16804843
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.	2006	16807036
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 ...	2006	16808859
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 ...	2006	16815722
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 ...	2006	16815726
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 ...	2006	16816180
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 ...	2006	16816191
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.	2006	16816205
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- ...	2006	16819825
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 ...	2006	16819902
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 ...	2006	16820314
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 ...	2006	16820464
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 ...	2006	16820499
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 ...	2006	16820760
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 ...	2006	16821725
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 ...	2006	16822688
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 ...	2006	16824040
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.	2006	16824652
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 ...	2006	16825349
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 ...	2006	16825363
molecular typing reveals a unique clone of salmonella enterica serotype typhi among indian strains.		2006	16825414
mucosal innate immune response to intragastric infection by salmonella enterica serovar choleraesuis.	the innate immune response is critical to enteric disease resistance and the induction of mucosal adaptive immunity. in mucosae of the small intestine, peyer's patches play a central role in immune surveillance and sampling of bacteria by specialized m cells. the innate immune response to salmonella enterica serovar choleraesuis, an enteric pathogen of swine, involves il-1beta and il-8 mrna induction but not that of il-6 and tnfalpha, in contrast to salmonella serovar typhimurium infection of mu ...	2006	16325910
differential effects of clathrin and actin inhibitors on internalization of escherichia coli and salmonella choleraesuis in porcine jejunal peyer's patches.	peyer's patches constitute both an inductive immune site and an enteropathogen invasion route. peyer's patch mucosae from porcine jejunum were mounted in ussing chambers, and either salmonella choleraesuis vaccine strain sc-54 or non-pathogenic rodent and porcine escherichia coli strains contacted the peyer's patch mucosa for 90 min. internalized bacteria were quantified by a gentamicin resistance assay. monodansylcadaverine (300 microm, luminal addition), an inhibitor of clathrin-mediated endoc ...	2006	16326046
solution structure of yggx: a prokaryotic protein involved in fe(ii) trafficking.	we report the three-dimensional structure of yggx from salmonella enterica, determined by solution nuclear magnetic resonance (nmr) spectroscopy from protein labeled with carbon-13 and nitrogen-15 produced by escherichia coli cells. the protein has a beta1beta2alpha1alpha2alpha3 fold that is unique to yggx and one of its homologs, a protein from pseudomonas aeruginosa with 45% sequence identity whose x-ray structure [protein data bank (pdb) 1t07] was determined by a structural genomics center. t ...	2006	16329120
infections associated with cantaloupe consumption: a public health concern.	fresh produce is an important part of a healthy diet and is consumed in greater quantity in the united states than ever before. consumption of cantaloupe has recently been associated with several large outbreaks of infections in north america, highlighting the need for a better understanding of practices and processes that may contribute to contamination. we reviewed all cantaloupe-associated outbreaks that were reported to the centers for disease control and prevention (cdc) and published in th ...	2006	16318654
distribution and function of plasmids in salmonella enterica.	plasmids of salmonella enterica vary in size from 2 to more than 200 kb. the best described group of plasmids are the virulence plasmids (50-100 kb in size) present in serovars enteritidis, typhimurium, dublin, cholerae-suis, gallinarum, pullorum and abortus-ovis. they all encode spvrabcd genes involved in intra-macrophage survival of salmonella. another group of high molecular weight plasmids are plasmids responsible for antibiotic resistance. since most of these plasmids are conjugative, besid ...	2006	16303262
molecular analysis of salmonella enterica subsp. enterica serovar agona isolated from slaughter pigs.	salmonella enterica subsp. enterica (s.) serovar agona plays an important role in brazil as causative agent of salmonellosis in food-producing animals - in particular, pigs and poultry - as well as in humans. a total of 45 s. agona isolates collected from slaughter pigs at three different slaughterhouses in southern brazil was investigated in this study for their phenotypic and genotypic relatedness. for this, the antimicrobial susceptibility patterns and the phage types were determined. molecul ...	2006	16289951
molecular epidemiology of emergent multidrug-resistant salmonella enterica serotype typhimurium strains carrying the virulence resistance plasmid puo-stvr2.	to evaluate the incidence of a distinct multidrug-resistant (mdr) grouping of salmonella serotype typhimurium strains carrying the hybrid virulence resistance plasmid puo-stvr2, and its possible evolution in the region where it was first detected [principality of asturias (pa), spain].	2006	16286360
complete nucleotide sequence of pscv50, the virulence plasmid of salmonella enterica serovar choleraesuis sc-b67.	we carried out comparative analysis on the sequences of two 50-kb virulence plasmids of salmonella enterica serovar choleraesuis strains sc-b67 (pscv50) and rf-1 (pkdsc50). the two plasmids share over 99% sequence similarity. ninety-two nucleotide variations at 42 sites were detected between the two plasmids; pscv50 contains 24 nucleotide substitutions, 6 deletions, and 62 insertions, compared to pkdsc50. two regions in pscv50 appeared to be more susceptible to changes: one is the non-virulence- ...	2006	16257053
kinetic analysis of the antibacterial activity of probiotic lactobacilli towards salmonella enterica serovar typhimurium reveals a role for lactic acid and other inhibitory compounds.	six lactobacillus strains including commercial probiotic ones (l. acidophilus ibb 801, l. amylovorus dce 471, l. casei shirota, l. johnsonii la1, l. plantarum aca-dc 287 and l. rhamnosus gg) were investigated, through batch fermentations under controlled conditions, for their capacity to inhibit salmonella enterica serovar typhimurium sl1344. all lactobacilli displayed strong antibacterial activity toward this gram-negative pathogen and significantly inhibited invasion of the pathogen into cultu ...	2006	16266797
cross-protective immunity in calves conferred by a dna adenine methylase deficient salmonellaenterica serovar typhimurium vaccine.	the global trend towards intensive livestock production is associated with increased fecal oral pathogen transmission resulting in a high prevalence of salmonella. since many pathogenic salmonella serovars are often endemic to livestock production systems, it is desirable to develop a vaccine that is capable of eliciting immunity to more than one serovar. here we examined whether immunization with a modified live salmonella enterica serovar typhimurium vaccine strain lacking the dna adenine meth ...	2006	16300866
feline cholecystitis and acute neutrophilic cholangitis: clinical findings, bacterial isolates and response to treatment in six cases.	clinicopathological findings from six cats with confirmed cholecystitis or acute neutrophilic cholangitis are presented. historical findings included lethargy and anorexia or inappetence of up to five days duration. on physical examination all cats were pyrexic and four out of six were jaundiced and had cranial abdominal pain. bile samples were obtained by cholecystocentesis at exploratory coeliotomy (two cases) or by percutaneous, ultrasound-guided cholecystocentesis (four cases). gall bladder ...	2006	16278090
the secreted salmonella dublin phosphoinositide phosphatase, sopb, localizes to ptdins(3)p-containing endosomes and perturbs normal endosome to lysosome trafficking.	invasion and survival in mammalian cells by salmonella enterica is mediated by bacterial proteins that are delivered to the host cell cytoplasm by type iii secretion systems. one of these proteins, sopb/sigd, is a phosphoinositide phosphatase that can hydrolyse a number of substrates in vitro including ptdins(3,5)p2. these substrates are, however, likely to be restricted in vivo by the localization of sopb, as different phosphoinositides have distinct spatial distributions in mammalian cells. in ...	2006	16396630
assessing genetic diversity in plasmids from escherichia coli and salmonella enterica using a mixed-plasmid microarray.	to compare genetic composition of plasmids using microarrays composed of randomly selected fragments of plasmid dna.	2006	16405681
use of igg avidity elisa to differentiate acute from persistent infection with salmonella dublin in cattle.	to investigate whether an immunoglobulin (ig)g avidity elisa can be used to differentiate between acute and persistent infection with salmonella (s.) dublin in cattle. to determine whether the igg isotype, igg(1) and igg(2) responses in acute and persistent infections differ.	2006	16405694
trends in antimicrobial resistance phenotypes in non-typhoid salmonellae from human and poultry origins in france.	a total of 1873 strains from human origin and 4283 strains from non-human origin of salmonella enterica serotypes typhimurium, enteritidis, heidelberg, hadar and virchow, collected over three years 1993, 1997 and 2000, were examined in order to determine the rate of antimicrobial resistance to 12 antimicrobial drugs. the objective of the study was to describe and to compare the evolution of the main resistance types in human and non-human isolates, focusing on the poultry sector. the evolution a ...	2006	16409665
dna examination of ancient dental pulp incriminates typhoid fever as a probable cause of the plague of athens.	until now, in the absence of direct microbiological evidence, the cause of the plague of athens has remained a matter of debate among scientists who have relied exclusively on thucydides' narrations to introduce several possible diagnoses. a mass burial pit, unearthed in the kerameikos ancient cemetery of athens and dated back to the time of the plague outbreak (around 430 bc), has provided the required skeletal material for the investigation of ancient microbial dna.	2006	16412683
rational design of salmonella-based vaccination strategies.	a permanently growing body of information is becoming available about the quality of protective immune responses induced by mucosal immunization. attenuated live bacterial vaccines can be administered orally and induce long-lasting protective immunity in humans without causing major side effects. an attenuated salmonella enterica serovar typhi strain is registered as live oral vaccine against typhoid fever and has been in use for more than two decades. recombinant attenuated salmonella strains a ...	2006	16414270
sensitivities of foodborne pathogens to pressure changes.	eight foodborne pathogens were suspended in ultrahigh-temperature whole milk and treated at pressure levels of 0.1 to 690 mpa at 21.5 degrees c for 10 min. there was no clear trend in pressure resistance between gram-negative and gram-positive organisms. the order of the single strains tested, from most to least pressure sensitive, was vibrio parahaemolyticus < yersinia enterocolitica < listeria monocytogenes < salmonella enterica serovar typhimurium < s. enterica serovar enteritidis < escherich ...	2006	16416910
antimicrobial resistance types and genes in salmonella enterica infantis isolates from retail raw chicken meat and broiler chickens on farms.	salmonella enterica subsp. enterica serotype infantis isolates from retail raw chicken meat (n = 98) and broiler chickens on farms (n = 70) were examined for antimicrobial susceptibility and antimicrobial resistance genes. a total of 15 antimicrobial resistance types, 14 in meat and 10 in broiler isolates, were identified, and 9 of the 15 types were indistinguishable between meat and broiler isolates. resistance to both oxytetracycline and dihydrostreptomycin accounted for 94.0% of the resistanc ...	2006	16416922
characterization of virulence factors in the newly described salmonella enterica serotype keurmassar emerging in senegal (sub-saharan africa).	from 2000 to 2001, nine strains of salmonella enterica belonging to the new serotype keurmassar have been isolated from human and poultry samples at the senegalese national salmonella and shigella reference laboratory at the pasteur institute, in dakar. all strains carried virulence factors including salmonella pathogenicity islands (spi)-1, -2, -3 and -5 encoded genes. strains did not harbour virulence plasmid. ribotyping analysis revealed a single clone identical to salmonella decatur isolated ...	2006	16420724
an outbreak of human salmonellosis caused by ampicillin-resistant salmonella enterica serovar enteritidis pt13 in the czech republic.	in summer 2004, an outbreak caused by salmonella enterica serovar enteritidis phage type 13 (s. enteritidis pt13) was recorded in the czech republic. as well being a relatively rare phage type the strain was also ampicillin resistant. outbreak (n=39) and pre-outbreak isolates (n=13) were characterized by pulsed-field gel electrophoresis (pfge), beta-lactamase gene polymerase chain reaction and plasmid profile. the majority of outbreak isolates (n=37) were identical in xbai pfge profile, and two ...	2006	16420725
foodborne bacterial infection and hospitalization: a registry-based study.	foodborne bacterial gastrointestinal infections are important causes of morbidity and mortality worldwide, and despite successful control programs in some developed countries, these infections continue to have a major impact on public health and economy.	2006	16421794
salmonella porins induce a sustained, lifelong specific bactericidal antibody memory response.	we examined the ability of porins from salmonella enterica serovar typhi to induce a long-term antibody response in balb/c mice. these porins triggered a strong lifelong production of immunoglobulin g (igg) antibody in the absence of exogenous adjuvant. analysis of the igg subclasses produced during this antibody response revealed the presence of the subclasses igg2b, igg1, igg2a and weak igg3. despite the high homology of porins, the long-lasting anti-s. typhi porin sera did not cross-react wit ...	2006	16423041
differential reactive oxygen and nitrogen production and clearance of salmonella serovars by chicken and mouse macrophages.	the objective of the present study was to compare the uptake and killing of salmonella serovars by murine and avian macrophage cell lines. we used salmonella enterica serovars enteritidis (se338) and typhimurium (sr11) for this study. uptake of green fluorescent protein-labeled bacteria was measured using flow cytometry. cell sorting and plating of viable infected macrophages demonstrated that bacterial clearance was significantly better with j774a.1 compared with hd11 cells. hd11 cells produced ...	2006	16427126
improvement and validation of rapd in combination with pfge analysis of salmonella enterica ssp. enterica serovar senftenberg strains isolated from feed mills.	in 1995 and 1996 a swedish feed mill had problems due to a persistent contamination of salmonella enterica spp. enterica serovar senftenberg that was difficult to eliminate. forty-eight strains isolated from the feed mill, together with unrelated strains included to evaluate the discriminatory power and reproducibility, were analysed by pulsed-field gel electrophoresis (pfge). the source of contamination in the feed mill was identified and preventative measures were taken, that led to a resoluti ...	2006	16427217
real-time reverse transcription pcr for the quantification of the mnth expression of salmonella enterica as a function of growth phase and phagosome-like conditions.	this article presents an experimental design for measuring the mrna expression in salmonella enterica of the mnth gene in phagosome-mimicking conditions. the expression of mnth was quantified by real-time reverse transcription pcr for different s. enterica strains of porcine origin under different biological growth conditions which mimicked the environment inside the phagosome. the expression of mnth and the different control genes (16s rrna, rpod and gmk) varied according to the growth phase. f ...	2006	16378650
the expression of the virulence-associated effector protein gene avra is dependent on a salmonella enterica-specific regulatory function.	although the avra gene is prevalent among 80% of the salmonella enterica serovars, only a small number of them usually express the respective virulence-associated effector protein avra. however, under culture conditions below ph 6.0 many of the avra non-producer strains (e.g. s. agona, s. bovismorbificans, s. virchow) begin to produce avra, while some others remain silent. four phenotypical classes of s. enterica were identified under defined standard culture conditions: class 1 comprises strain ...	2006	16377240
ciprofloxacin-resistant salmonella enterica serovar typhimurium strains are difficult to select in the absence of acrb and tolc.	it has been proposed that lack of a functional efflux system(s) will lead to a lower frequency of selection of resistance to fluoroquinolones and other antibiotics. we constructed five strains of salmonella enterica serovar typhimurium sl1344 that lacked efflux gene components of resistance nodulation cell division pumps (acrb, acrd, acrf, acrbacrf, and tolc) plus three strains that lack genes that effect efflux gene expression (mara, soxs, and rama) and a hypermutable strain (muts::aph). strain ...	2006	16377664
identification of csrc and characterization of its role in epithelial cell invasion in salmonella enterica serovar typhimurium.	the csr regulatory system of salmonella regulates the expression of the genes of salmonella pathogenicity island 1 (spi1) required for the invasion of epithelial cells. this system consists of the posttranscriptional regulator csra and an untranslated regulatory rna, csrb, that opposes the action of csra. here we identify and characterize the role of a second regulatory rna, csrc, whose ortholog was discovered previously in escherichia coli. we show that a mutant of csrc has only mild defects in ...	2006	16368988
identification and characterization of a novel bacterial virulence factor that shares homology with mammalian toll/interleukin-1 receptor family proteins.	many important bacterial virulence factors act as mimics of mammalian proteins to subvert normal host cell processes. to identify bacterial protein mimics of components of the innate immune signaling pathway, we searched the bacterial genome database for proteins with homology to the toll/interleukin-1 receptor (tir) domain of the mammalian toll-like receptors (tlrs) and their adaptor proteins. a previously uncharacterized gene, which we have named tlpa (for tir-like protein a), was identified i ...	2006	16369016
virulence of broad- and narrow-host-range salmonella enterica serovars in the streptomycin-pretreated mouse model.	salmonella enterica subspecies i serovars are common bacterial pathogens causing diseases ranging from enterocolitis to systemic infections. some serovars are adapted to specific hosts, whereas others have a broad host range. the molecular mechanisms defining the virulence characteristics and the host range of a given s. enterica serovar are unknown. streptomycin pretreated mice provide a surrogate host model for studying molecular aspects of the intestinal inflammation (colitis) caused by serov ...	2006	16369020
propionate-regulated high-yield protein production in escherichia coli.	a new expression system containing the salmonella enterica prpbcde promoter (p(prpb)) responsible for expression of the propionate catabolic genes (prp bcde) and prpr encoding the positive regulator of this promoter has been developed and tested. the main features of the expression system compared to those based on the bacteriophage t7 promoter are low background expression and high induced expression in escherichia coli strains bl21, bl21(de3), mg1655, and w3110. in addition, propionate is an i ...	2006	16333863
distribution of salmonella enterica serovars from humans, livestock and meat in vietnam and the dominance of salmonella typhimurium phage type 90.	epidemiologically unrelated non-typhoid salmonella isolates from humans (n = 56) and animal origin (n = 241, from faeces, carcasses and meat) in vietnam were investigated. salmonella typhimurium, s. anatum, s. weltevreden, s. emek, and s. rissen were the most prevalent serovars. s. typhimurium phage type 90 was predominant among s. typhimurium isolates. the serotype and phage type distribution of the salmonella isolates was different from that in europe and america. many sero- and phage types fo ...	2006	16337754
analysis of porcine differential gene expression following challenge with salmonella enterica serovar choleraesuis using suppression subtractive hybridization.	swine-adapted salmonella enterica subsp. enterica serovar choleraesuis (s. choleraesuis) is the pathogen most frequently isolated from diseased pigs and may affect host gene expression in a species-specific manner. to characterize the porcine transcriptional response to s. choleraesuis infection, the mrna profiles from the mesenteric lymph nodes of three non-infected and three experimentally infected pigs at 24 h post-inoculation were analyzed by suppression subtractive hybridization (ssh). fort ...	2006	16364571
cd154 is essential for protective immunity in experimental salmonella infection: evidence for a dual role in innate and adaptive immune responses.	cd40-cd154 interactions are of central importance in the induction of humoral and cellular immune responses. in the present study, cd154-deficient (cd154-/-) mice were used to assess the role of cd40-cd154 interactions in regulating the immune response to a systemic salmonella infection. compared with c57bl/6 (cd154+/+) controls, cd154-/- mice were hypersusceptible to infection by an attenuated strain of salmonella enterica serovar typhimurium (s. typhimurium), as evidenced by decreased survival ...	2006	16365443
virulence and drug resistance roles of multidrug efflux systems of salmonella enterica serovar typhimurium.	drug efflux systems play a major role in resistance to a wide range of noxious compounds in several gram negative species. here, we report the drug resistance and virulence phenotypes of salmonella mutants defective in either resistance-nodulation-division (rnd)-type systems and/or in drug efflux systems belonging to the major facilitator (mfs), multidrug and toxic compound extrusion (mate), and atp-binding cassette (abc) superfamilies. we determined that nine potential drug transporters contrib ...	2006	16359323
coordinated expression and immunogenicity of an outer membrane protein from salmonella enterica serovar typhi under iron limitation, oxidative stress and anaerobic conditions.	successful pathogens overcome the environmental stresses by the coordinated expression of various genes and eventually proteins. since, the surface of the microbe is likely to come in contact with the host initially, an attempt was made to identify the outer membrane proteins (omps), if any, which may get expressed under more than one environmental conditions simulating the in vivo ones. in the present study, salmonella enterica serovar typhi was grown under iron-limited, oxidative stress as wel ...	2006	16362827
a high-performance liquid chromatography-tandem mass spectrometry method for quantitation of nitrogen-containing intracellular metabolites.	a comprehensive method of quantifying intracellular metabolite concentrations would be a valuable addition to the arsenal of tools for holistic biochemical studies. here, we describe a step toward the development of such method: a quantitative assay for 90 nitrogen-containing cellular metabolites. the assay involves reverse-phase high-performance liquid chromatography separation followed by electrospray ionization and detection of the resulting ions using triple-quadrupole mass spectrometry in s ...	2006	16352439
genetic relatedness of a rarely isolated salmonella: salmonella enterica serotype niakhar from narms animal isolates.	in the united states, salmonella enterica serotype niakhar is infrequently isolated. between 1997 and 2000, the animal arm of the national antimicrobial resistance monitoring system-enteric bacteria (narms) assayed a total of 22,383 salmonella isolates from various animal sources (swine, cattle, chickens, turkeys, cats, horses, exotics and dogs) for antimicrobial susceptibility. isolates originated from diagnostic and non-diagnostic submissions.	2006	16352736
genetic transplantation: salmonella enterica serovar typhimurium as a host to study sigma factor and anti-sigma factor interactions in genetically intractable systems.	in salmonella enterica serovar typhimurium, sigma(28) and anti-sigma factor flgm are regulatory proteins crucial for flagellar biogenesis and motility. in this study, we used s. enterica serovar typhimurium as an in vivo heterologous system to study sigma(28) and anti-sigma(28) interactions in organisms where genetic manipulation poses a significant challenge due to special growth requirements. the chromosomal copy of the s. enterica serovar typhimurium sigma(28) structural gene flia was exchang ...	2006	16352826
role of salmonella enterica serovar typhimurium two-component system prea/preb in modulating pmra-regulated gene transcription.	the pmra/pmrb two-component system encoded by the pmrcab operon regulates the modification of salmonella enterica serovar typhimurium lipopolysaccharide leading to polymyxin b resistance. pmra and phop are the only known activators of pmrcab. a transposon mutagenesis screen for additional regulators of a pmrc::mudj fusion led to the identification of a two-component system, termed prea/preb (pmrcab regulators a and b), that controls the transcription of the pmrcab operon in response to unknown s ...	2006	16352830
the pseudomonas aeruginosa lipid a deacylase: selection for expression and loss within the cystic fibrosis airway.	lipopolysaccharide (lps) is the major surface component of gram-negative bacteria, and a component of lps, lipid a, is recognized by the innate immune system through the toll-like receptor 4/md-2 complex. pseudomonas aeruginosa, an environmental gram-negative bacterium that opportunistically infects the respiratory tracts of patients with cystic fibrosis (cf), can synthesize various structures of lipid a. lipid a from p. aeruginosa strains isolated from infants with cf has a specific structure t ...	2006	16352835
comparative and functional genomic analysis of prokaryotic nickel and cobalt uptake transporters: evidence for a novel group of atp-binding cassette transporters.	the transition metals nickel and cobalt, essential components of many enzymes, are taken up by specific transport systems of several different types. we integrated in silico and in vivo methods for the analysis of various protein families containing both nickel and cobalt transport systems in prokaryotes. for functional annotation of genes, we used two comparative genomic approaches: identification of regulatory signals and analysis of the genomic positions of genes encoding candidate nickel/cob ...	2006	16352848
visualization of vacuolar acidification-induced transcription of genes of pathogens inside macrophages.	the objective of these studies was to analyze the role of the ionic environment of phagosomal vacuoles in the control of pathogens by macrophages. digital imaging and flow cytometry were used to follow the induction of the phop promoter of salmonella enterica typhimurium within live macrophages. manipulating the mg2+ concentration within the salmonella-containing vacuole (scv) was without effect on the early induction of phopq. moreover, direct measurement of [mg2+] within the scv using nanosens ...	2006	16251362
adaptation of multilocus sequencing for studying variation within a major clone: evolutionary relationships of salmonella enterica serovar typhimurium.	serovar typhimurium of salmonella enterica is a model organism for studies of pathogenesis that exhibits phage-type variation and variation in host range and virulence, but in a recent study showed no sequence variation in four genes, indicating the clonal nature of this serovar. we determined the relationships of 46 typhimurium isolates of nine phage types using mutational changes detected either by matching aflp (amplified fragment length polymorphism) fragments to computer-modeled lt2 aflp fr ...	2006	16204219
bacterial histidine kinase as signal sensor and transducer.	adaptation to an environmental stress is essential for cell survival in all organisms, from e. coli to human. to respond to changes in their surroundings, bacteria utilize two-component systems (tcss), also known as histidyl-aspartyl phosphorelay (hap) systems that consist of a histidine kinase (hk) sensor and a cognate response regulator (rr). while mammals developed complex signaling systems involving serine/threonine/tyrosine kinases in stress response mechanisms, bacterial tcs/hap systems re ...	2006	16242988
resuscitation of the viable but non-culturable state of salmonella enterica serovar oranienburg by recombinant resuscitation-promoting factor derived from salmonella typhimurium strain lt2.	a gene encoding the resuscitation-promoting factor (rpf) from salmonella typhimurium lt2 was cloned and characterized. the amino acid sequence encoded by s. typhimurium lt2 rpf gene shares 24.2% homology with micrococcus luteus rpf, which is secreted by growing cells, and required to resuscitate from viable but non-culturable (vnc) state. the s. typhimurium lt2 rpf gene is 696 bp long, and shared a conserved segment with salmonella enterica serovar oranienburg (99.4%). recombinant rpf (rrpf) pro ...	2006	16213054
catecholate receptor proteins in salmonella enterica: role in virulence and implications for vaccine development.	three outer membrane proteins of salmonella enterica serovar typhimurium function as catecholate siderophore receptors. iron promotes uptake of enterobactin, salmochelins and 2,3-dihydroxybenzoylserine, fepa transports enterobactin and 2,3-dihydroxybenzoylserine, and cir is a receptor for 2,3-dihydroxybenzoylserine. in addition, all three proteins are required for l-norepinephrine-facilitated iron uptake from transferrin as judged by failure of a fepa iron cir triple mutant to grow in serum-cont ...	2006	16154248
enhanced contrast of bacteriophage plaques in salmonella with ferric ammonium citrate and sodium thiosulfate (facst) and tetrazolium red (tzr).	visualization of bacteriophage plaques may be enhanced by addition of ferric ammonium citrate and sodium thiosulfate (facst) or 2,3,5-triphenyltetrazolium chloride (tetrazolium red, tzr) to the soft agar layer of a traditional bacteriophage plaque assay. background color from these reagents improved contrast between clear plaques and turbid host lawns in trypticase soy agar (tsa) plates. enhancement by facst is based on reaction with hydrogen sulfide gas (h2s) produced by some strains of bacteri ...	2006	16182396
differential detection of turkey coronavirus, infectious bronchitis virus, and bovine coronavirus by a multiplex polymerase chain reaction.	the objective of the present study was to develop a multiplex polymerase chain reaction (pcr) method for differential detection of turkey coronavirus (tcov), infectious bronchitis coronavirus (ibv), and bovine coronavirus (bcov). primers were designed from conserved or variable regions of nucleocapsid (n) or spike (s) protein gene among tcov, ibv, and bcov and used in the same pcr reaction. reverse transcription followed by the pcr reaction was used to amplify a portion of n or s gene of the cor ...	2006	16137773
a family of arabinose-inducible escherichia coli expression vectors having pbr322 copy control.	the pbad series of expression vectors have been widely used in escherichia coli, salmonella enterica, and related bacteria. however, a complication with pbad24, the most popular of these plasmids, is that it does not contain the complete functional replication origin of pbr322 as was depicted in the original paper. instead, pbad24 has a pbr322-derived origin that lacks the rop gene that negatively regulates copy number and thus pbad24 has an appreciably higher copy number than that of pbr322, pa ...	2006	16139359
evaluation of salmonella enterica serovar typhi (ty2 aroc-ssav-) m01zh09, with a defined mutation in the salmonella pathogenicity island 2, as a live, oral typhoid vaccine in human volunteers.	salmonella enterica serovar typhi strains with mutations in the salmonella pathogenicity island-2 (spi-2) may represent an effective strategy for human vaccine development, and a vectoring system for heterologous antigens. s. typhi (ty2 aroc-ssav-) m01zh09 is an attenuated, live, oral typhoid vaccine harboring defined deletion mutations in ssav, which encodes an integral component in the spi-2 type iii secretion system (ttss), as well as a mutation in an aromatic biosynthetic pathway needed for ...	2006	16140433
the long polar fimbriae genes identified in shiga toxin-producing escherichia coli are present in other diarrheagenic e. coli and in the standard e. coli collection of reference (ecor) strains.	long polar fimbriae (lpf) are related to type i fimbriae in genetic organization and were first identified in salmonella enterica serovar typhimurium. four lpfa genetic variants designated lpfa(o157/oi-141), lpfa(o157/oi-154), lpfa(o26) and lpfa(o113) have been identified in shiga toxin-producing escherichia coli (stec). in this study, pcr was employed to determine the distribution of stec-lpfas in enteropathogenic, enteroaggregative, enterotoxigenic and enteroinvasive e. coli (epec, eaec, etec ...	2006	16125910
insertion-duplication mutagenesis of salmonella enterica and related species using a novel thermosensitive vector.	we constructed a novel temperature-sensitive vector as a tool for gene disruption by insertion-duplication mutagenesis (idm) in salmonella enterica and related species. a phon insertion mutant was proven highly stable during growth in lb medium and during infection of macrophage cells in the absence of selection pressure. by progressive shortening of a phon fragment, the minimal length for effective insertional mutagenesis driven by homologous recombination was determined to be 50 bp, allowing t ...	2006	16125236