Publications

in vivo induced antigen technology (iviat) and change mediated antigen technology (cmat).	in this chapter, an overview of in vivo induced antigen technology (iviat) and change mediated antigen technology (cmat) will be presented, including a discussion of the advantages and limitations of these methods. over fifteen different microbial pathogens have been or are known to be currently studied with these methods. salient data obtained from the application of iviat and/or cmat to a selection of human and plant pathogens will be summarized. this includes recent reports on streptococcus p ...	2006	16918490
prophylactic anti-tumor immunity against a murine fibrosarcoma triggered by the salmonella type iii secretion system.	the potential of an attenuated salmonella enterica serovar typhimurium strain as a prophylactic anti-tumor vaccine against the murine fibrosarcoma wehi 164 was evaluated. tumor cells were transfected with the dna sequence encoding the mhc class i-restricted peptide p60(217-225) from listeria monocytogenes. balb/c mice received a single orogastric immunization with salmonella that translocates a chimeric p60 protein via its type iii secretion system. mice were subsequently challenged subcutaneous ...	2006	16919987
the pilz domain is a receptor for the second messenger c-di-gmp: the pilz domain protein ycgr controls motility in enterobacteria.	the ubiquitous bacterial second messenger c-di-gmp controls exopolysaccharide synthesis, flagella- and pili-based motility, gene expression, and interactions of bacteria with eukaryotic hosts. with the exception of bacterial cellulose synthases, the identities of c-di-gmp receptors and end targets have remained unknown. recently, amikam and galperin (amikam, d., and galperin, m. (2006) bioinformatics 22, 3-6) hypothesized that the pilz domains present in the bcsa subunits of bacterial cellulose ...	2006	16920715
triclosan and antimicrobial resistance in bacteria: an overview.	triclosan is a widely used biocide that is considered as an effective antimicrobial agent against different microorganisms. it is included in many contemporary consumer and personal health-care products, like oral and dermal products, but also in household items, including plastics and textiles. at bactericidal concentrations, triclosan appears to act upon multiple nonspecific targets, causing disruption of bacterial cell wall functions, while at sublethal concentrations, triclosan affects speci ...	2006	16922622
serologic evidence for effective production of cytolysin a in salmonella enterica serovars typhi and paratyphi a during human infection.	clyasty and clyaspaa are closely related pore-forming cytolysins of salmonella enterica serovars typhi and paratyphi a whose expression is strongly repressed under standard in vitro growth conditions. we show here that human infections by these pathogens cause a specific antibody response to clya, indicating effective toxin production during infection.	2006	16923786
allosteric control of cyclic di-gmp signaling.	cyclic di-guanosine monophosphate is a bacterial second messenger that has been implicated in biofilm formation, antibiotic resistance, and persistence of pathogenic bacteria in their animal host. although the enzymes responsible for the regulation of cellular levels of c-di-gmp, diguanylate cyclases (dgc) and phosphodiesterases, have been identified recently, little information is available on the molecular mechanisms involved in controlling the activity of these key enzymes or on the specific ...	2006	16923812
partial purification and cytotoxic effects of salmonella proteinous moieties on chick embryo fibroblasts.	salmonella enterica serovars, viz., s. weltevreden, s. typhimurium, s. gallinarum and s. bareilly were treated with cephotaxime to release of intracellular proteins. the cephotaxime extract (ce) was salt precipitated with ammonium sulphate (45-70%) and dialyzed, and denoted as precipitated dialyzed proteins (pdp). further, both ce and pdp of salmonella weltevreden and pdp of rest of the serovars were subjected to gel filtration using sephacryl s-200hr. different fractions along with ce and pdp w ...	2006	16924838
exopolysaccharides produced by probiotic strains modify the adhesion of probiotics and enteropathogens to human intestinal mucus.	exopolysaccharides (epss) are exocellular polymers present in the surface of many bacteria, including lactobacillus and bifidobacterium. the genome sequence of several strains revealed the presence of eps-encoding genes. however, the physiological role that epss play in the bacterial ecology still remains uncertain. in this study, we have assessed the effect of epss produced by lactobacillus rhamnosus gg, bifidobacterium longum nb667, and bifidobacterium animalis ipla-r1 on the adhesion of probi ...	2006	16924934
microbial evasion of the immune system: structural modifications of enterobactin impair siderocalin recognition.	the mammalian protein siderocalin binds and inactivates the ferric complex of the bacterial siderophore enterobactin with a kd value similar to that of the bacterial receptor fepa. however, microorganisms can evade this immune response by structural modifications of the siderophore. the binding of siderophores by siderocalin relies in part on electrostatic interactions and does not depend greatly on what metal is in the complex. it is also sterically limited by the rigid conformation of the prot ...	2006	16925397
detection of egg yolk antibodies reflecting salmonella enteritidis infections using a surface plasmon resonance biosensor.	a surface plasmon resonance (spr) biosensor assay was developed on the basis of a lipopolysaccharide antigen of salmonella enterica serovar enteritidis (s. enterica serovar enteritidis) to detect egg yolk antibodies against s. enterica serovar enteritidis. this biosensor assay was compared to two commercial elisa kits based on lps antigen and flagellar antigen. a number of 163 egg yolk and combined egg white and yolk samples from chickens experimentally infected with s. enterica serovar enteriti ...	2006	16926019
chronic salmonella enterica serovar typhimurium-induced colitis and cholangitis in streptomycin-pretreated nramp1+/+ mice.	salmonella enterica subspecies 1 serovar typhimurium is an enteric bacterial pathogen infecting a broad range of hosts. in susceptible nramp1(-/-) (slc11alpha1(-/-)) mice, serovar typhimurium cannot efficiently colonize the intestine but causes a systemic typhoid-like infection. however, after pretreatment with streptomycin, these susceptible (c57bl/6 and balb/c) mice develop acute serovar typhimurium-induced colitis (m. barthel et al., infect. immun. 71:2839-2858, 2003). it was not clear whethe ...	2006	16926396
thioredoxin 1 promotes intracellular replication and virulence of salmonella enterica serovar typhimurium.	the effect of the cytoplasmic reductase and protein chaperone thioredoxin 1 on the virulence of salmonella enterica serovar typhimurium was evaluated by deleting the trxa, trxb, or trxc gene of the cellular thioredoxin system, the grxa or gsha gene of the glutathione/glutaredoxin system, or the dsbc gene coding for a thioredoxin-dependent periplasmic disulfide bond isomerase. mutants were tested for tolerance to oxidative and nitric oxide donor substances in vitro, for invasion and intracellular ...	2006	16926406
identification of in vivo-induced bacterial protein antigens during human infection with salmonella enterica serovar typhi.	we applied an immunoscreening technique, in vivo-induced antigen technology (iviat), to identify immunogenic bacterial proteins expressed during human infection with salmonella enterica serovar typhi, the cause of typhoid fever. we were able to assign a functional classification to 25 of 35 proteins identified by iviat. of these 25, the majority represent proteins with known or potential roles in the pathogenesis of s. enterica. these include proteins implicated in fimbrial structure and biogene ...	2006	16926408
morphine withdrawal lowers host defense to enteric bacteria: spontaneous sepsis and increased sensitivity to oral salmonella enterica serovar typhimurium infection.	understanding the consequences of drug withdrawal on immune function and host defense to infection is important. we, and others, previously demonstrated that morphine withdrawal results in immunosuppression and sensitizes to lipopolysaccharide-induced septic shock. in the present study, the effect of morphine withdrawal on spontaneous sepsis and on oral infection with salmonella enterica serovar typhimurium was examined. mice were chronically exposed to morphine for 96 h by implantation of a slo ...	2006	16926415
the salmonella enterica serovar typhi type ivb self-association pili are detached from the bacterial cell by the pilv minor pilus proteins.	salmonella enterica serovar typhi and some strains (vi+) of serovar dublin use type ivb pili to facilitate bacterial self-association, but only when the pilv proteins (potential minor pilus proteins) are not synthesized. pilus-mediated self-association may be important in the pathogenesis of enteric fever. we have shown previously that the extent of dna supercoiling controls the rate of rci-catalyzed inversion of a dna fragment which includes the c-terminal portions of the pilv proteins. this in ...	2006	16926438
predictive efficacy of nalidixic acid resistance as a marker of fluoroquinolone resistance in salmonella enterica var typhi.	resistance in salmonella enterica var typhi (s. typhi) to chloramphenicol, amoxicillin and co-trimoxazole has posed a challenge to treatment of typhoid fever. ciprofloxacin has been the empirical therapy of choice, but the recent increase in minimum inhibitory concentration (mic) to ciprofloxacin in s. typhi, not detectable by disc diffusion (dd) tests, may result in delayed response and serious complications. nalidixic acid (na) resistance has been used as an indirect evidence of increased cipr ...	2006	16926465
h-ns mediates the silencing of laterally acquired genes in bacteria.	histone-like nucleoid structuring protein (h-ns) is a modular protein that is associated with the bacterial nucleoid. we used chromatin immunoprecipitation to determine the binding sites of h-ns and rna polymerase on the salmonella enterica serovar typhimurium chromosome. we found that h-ns does not bind to actively transcribed genes and does not co-localize with rna polymerase. this shows that h-ns principally silences gene expression by restricting the access of rna polymerase to the dna. h-ns ...	2006	16933988
herd-level risk factors for salmonella enterica subsp. enterica in u.s. market pigs.	midwest u.s. herds (n=63) were studied to identify risk factors for harboring salmonella enterica among slaughter-weight pigs. samples collected on farms (feces) and at slaughter (distal colonic content, cecal content and ileocolic lymph nodes) were cultured using conventional means. approximately 15 pigs were studied per herd, for a total of 3754 samples. the proportion of pigs positive in one or more samples was calculated for each herd. herd characteristics were described by a combination of ...	2006	16828183
tumour necrosis factor alpha mediated apoptosis in murine macrophages by salmonella enterica serovar typhi under oxidative stress.	invasive salmonella has been reported to induce apoptosis of macrophages as part of its infection process, which may allow it to avoid detection by the innate immune system. however, the induction of apoptosis under the different host environments remains to be examined, including the oxidative stress experienced by pathogens in the macrophage milieu. to simulate in vivo oxidative conditions, salmonella enterica serovar typhi was grown in the presence of hydrogen peroxide and its ability to indu ...	2006	16831216
antimicrobial potential of four lactobacillus strains isolated from breast milk.	the antimicrobial potential of four lactobacilli (lactobacillus salivarius cect5713, lactobacillus gasseri cect5714, l. gasseri cect5715 and lactobacillus fermentum cect5716), isolated from fresh human breast milk, was evaluated in this study and compared with lactobacillus coryniformis cect5711, a reuterin-producing strain isolated from an artisan goat's cheese.	2006	16834593
the newly isolated lytic bacteriophages st104a and st104b are highly virulent against salmonella enterica.	to screen irish faecal samples from a variety of sources with a view to isolating novel anti-salmonella phages and to subsequently evaluate their lytic capability.	2006	16834613
consumer-phase salmonella enterica serovar enteritidis risk assessment for egg-containing food products.	we describe a one-dimensional probabilistic model of the role of domestic food handling behaviors on salmonellosis risk associated with the consumption of eggs and egg-containing foods. six categories of egg-containing foods were defined based on the amount of egg contained in the food, whether eggs are pooled, and the degree of cooking practiced by consumers. we used bootstrap simulation to quantify uncertainty in risk estimates due to sampling error, and sensitivity analysis to identify key so ...	2006	16834632
effect of immune serum and role of individual fcgamma receptors on the intracellular distribution and survival of salmonella enterica serovar typhimurium in murine macrophages.	immune serum has a protective role against salmonella infections in mice, domestic animals and humans. in this study, the effect of antibody on the interaction between murine macrophages and s. enterica serovar typhimurium was examined. detailed analysis at the single-cell level demonstrated that opsonization of the bacteria with immune serum enhanced bacterial uptake and altered bacterial distribution within individual phagocytic cells. using gene-targeted mice deficient in individual fc gamma ...	2006	16836651
interpolated variable order motifs for identification of horizontally acquired dna: revisiting the salmonella pathogenicity islands.	there is a growing literature on the detection of horizontal gene transfer (hgt) events by means of parametric, non-comparative methods. such approaches rely only on sequence information and utilize different low and high order indices to capture compositional deviation from the genome backbone; the superiority of the latter over the former has been shown elsewhere. however even high order k-mers may be poor estimators of hgt, when insufficient information is available, e.g. in short sliding win ...	2006	16837528
salmonella enterica serotype enteritidis and eggs: a national epidemic in the united states.	beginning in the 1970s, the incidence of salmonella enterica serotype enteritidis (se) infection and the number of related outbreaks in the united states has increased dramatically. by 1994, se was the most commonly reported salmonella serotype, with an incidence of >10 laboratory-confirmed infections per 100,000 population in the northeast. intensive epidemiologic and laboratory investigations identified shell eggs as the major vehicle for se infection in humans, and that the eggs had been inte ...	2006	16838242
pyrolysis mass spectrometry for distinguishing potential hoax materials from bioterror agents.	pyrolysis mass spectrometry (pyms) was investigated as a rapid tool to distinguish potential bioterror hoax materials from samples containing pathogenic bacteria. a pyrolysis time-of-flight (tof) mass spectrometer equipped with an alternative ionization technique, metastable atom bombardment (mab), was used to produce sample spectra. these spectra were analyzed by principal component and discriminant analysis for pattern recognition. materials investigated were two strains of vibrio parahaemolyt ...	2006	16841357
multi-drug resistance in salmonella enterica: efflux mechanisms and their relationships with the development of chromosomal resistance gene clusters.	bacterial drug resistance represents one of the most crucial problems in present day antibacterial chemotherapy. of particular concern to public health is the continuing worldwide epidemic spread of salmonella enterica serovar typhimurium phage type dt104 harbouring a genomic island called salmonella genomic island i (sgi-1). this island contains an antibiotic gene cluster conferring resistance to ampicillin, chloramphenicol, florfenicol, streptomycin, sulfonamides and tetracyclines. these resis ...	2006	16842216
the salmonella enterica serovar typhi vi capsule and self-association pili share controls on expression.	salmonella enterica serovar typhi uses type ivb pili to facilitate eukaryotic cell invasion. here, we compare environmental and genetic controls on pil operon transcription with those regulating viab genes required for vi antigen expression. transcription of pil occurs only in the late logarithmic and stationary phases of bacterial growth while viab expression occurs in the logarithmic growth phase. expression of both viab and pil was, however, optimal at 100 mm nacl, and mutations in envz/ompr, ...	2006	16842356
characterization of the sigmae-dependent rpoep3 promoter of salmonella enterica serovar typhimurium.	using a two-plasmid system, we recently identified sigma(e)-dependent promoters directing expression of the sigma(e) regulon genes in salmonella enterica serovar typhimurium (s. typhimurium). comparison of the promoters revealed a consensus sequence almost identical to the sigma(e)-dependent rpoep3 promoter directing expression of rpoe. this two-plasmid system was previously optimized to identify nucleotides critical for the rpoep3 promoter activity. however, two highly conserved nucleotides in ...	2006	16842358
regulatory components at the csgd promoter--additional roles for ompr and integration host factor and role of the 5' untranslated region.	csgd is a master regulator of multicellular behaviour in salmonella enterica serovar typhimurium. expression of csgd is highly regulated on the transcriptional level. a nucleo-protein complex had been defined where the global regulators ompr and integration host factor (ihf) bind up- and downstream of the csgd core promoter. in this study, the nucleo-protein complex of pcsgd was extended through characterization of additional ompr and ihf binding sites that influence the transcriptional activity ...	2006	16842367
isolation of bacteriocinogenic lactobacillus plantarum strains from ben saalga, a traditional fermented gruel from burkina faso.	a collection of lactic acid bacteria isolated from ben saalga, a traditional fermented gruel from burkina faso, was screened for bacteriocin production. seven isolates were selected for their broad antimicrobial spectra, which overall included strains of bacillus cereus, bacillus licheniformis, enterococcus faecalis, listeria innocua, listeria monocytogenes, staphylococcus aureus, escherichia coli and salmonella enterica. cluster analysis of rapd-pcr patterns revealed that six of the isolates re ...	2006	16844251
regulatory protein that inhibits both synthesis and use of the target protein controls flagellar phase variation in salmonella enterica.	flagellin is a major surface antigen for many bacterial species. the pathogen salmonella enterica switches between two alternative, antigenic forms of its flagellin filament protein, either type b or c. this switching (flagellar phase variation) is achieved by stochastic inversion of a promoter that produces both type b flagellin (fljb) and an inhibitor (flja) of type c flagellin formation. when the fljb-flja operon is expressed, only type b flagella are produced; when the operon is not transcri ...	2006	16844786
multidrug-resistance efflux pumps - not just for resistance.	it is well established that multidrug-resistance efflux pumps encoded by bacteria can confer clinically relevant resistance to antibiotics. it is now understood that these efflux pumps also have a physiological role(s). they can confer resistance to natural substances produced by the host, including bile, hormones and host-defence molecules. in addition, some efflux pumps of the resistance nodulation division (rnd) family have been shown to have a role in the colonization and the persistence of ...	2006	16845433
gene expression profiling in salmonella choleraesuis-infected porcine lung using a long oligonucleotide microarray.	understanding the transcriptional response to pathogenic bacterial infection within food animals is of fundamental and applied interest. to determine the transcriptional response to salmonella enterica serovar choleraesuis (sc) infection, a 13,297-oligonucleotide swine array was used to analyze rna from control, 24-h postinoculation (hpi), and 48-hpi porcine lung tissue from pigs infected with sc. in total, 57 genes showed differential expression (p < 0.001; false discovery rate = 12%). quantita ...	2006	16845603
delayed expansion and contraction of cd8+ t cell response during infection with virulent salmonella typhimurium.	ag presentation to cd8(+) t cells often commences immediately after infection, which facilitates their rapid expansion and control of infection. subsequently, the primed cells undergo rapid contraction. we report that this paradigm is not followed during infection with virulent salmonella enterica, serovar typhimurium (st), an intracellular bacterium that replicates within phagosomes of infected cells. although susceptible mice die rapidly (approximately 7 days), resistant mice (129 x 1svj) harb ...	2006	16849458
mutational analysis of salmonella translocated effector members sifa and sopd2 reveals domains implicated in translocation, subcellular localization and function.	salmonella enterica serovar typhimurium is a facultative intracellular pathogen causing disease in several hosts. these bacteria use two distinct type iii secretion systems that inject effector proteins into the host cell for invasion and to alter maturation of the salmonella-containing vacuole. members of the salmonella translocated effector (ste) family contain a conserved n-terminal translocation signal of approximately 140 aa. in this study, the ste family member sifa was examined using dele ...	2006	16849798
a connection between iron-sulfur cluster metabolism and the biosynthesis of 4-amino-5-hydroxymethyl-2-methylpyrimidine pyrophosphate in salmonella enterica.	several cellular pathways have been identified which affect the efficiency of thiamine biosynthesis in salmonella enterica. mutants defective in iron-sulfur (fe-s) cluster metabolism are less efficient at synthesis of the pyrimidine moiety of thiamine. these mutants are compromised for the conversion of aminoimidazole ribotide (air) to 4-amino-5-hydroxymethyl-2-methylpyrimidine phosphate (hmp-p), not the synthesis of air. the gene product thic contains potential ligands for an fe-s cluster that ...	2006	16849799
differences in resistance to salmonella enterica serovar gallinarum infection among indigenous local chicken ecotypes in tanzania.	a study was conducted to evaluate the disease resistance potential in 105 chickens of six indigenous local chicken ecotypes in tanzania by orally challenging 1-week-old chicks with 2.5 x 10(8) colony-forming units of virulent s. gallinarum. for 14 days post infection, clinical signs, necropsy findings, antibody titres, packed cell volume, leukocyte population count, and viable bacterial cell counts in the liver and spleen were recorded. clinical signs were recorded daily but other parameters wer ...	2006	16854638
the fad-dependent tricarballylate dehydrogenase (tcua) enzyme of salmonella enterica converts tricarballylate into cis-aconitate.	tricarballylate is the causative agent of grass tetany, a ruminant disease characterized by acute magnesium deficiency. tricarballylate toxicity has been attributed to its ability to chelate magnesium and to inhibit aconitase, a krebs cycle enzyme. neither the ruminant nor the normal rumen flora can catabolize tricarballylate to ameliorate its toxic effects. however, the gram-negative enterobacterium salmonella enterica can use tricarballylate as a carbon and energy source, providing an opportun ...	2006	16855237
the mgtc virulence factor of salmonella enterica serovar typhimurium activates na(+),k(+)-atpase.	the mgtc gene of salmonella enterica serovar typhimurium encodes a membrane protein of unknown function that is important for full virulence in the mouse. since mgtc is part of an operon with mgtb which encodes a mg(2+)-transporting p-type atpase, mgtc was hypothesized to function in ion transport, possibly in mg(2+) transport. consequently, mgtc was expressed in xenopus laevis oocytes, and its effect on ion transport was evaluated using ion selective electrodes. oocytes expressing mgtc did not ...	2006	16855249
crystal structure of tdp-fucosamine acetyltransferase (wecd) from escherichia coli, an enzyme required for enterobacterial common antigen synthesis.	enterobacterial common antigen (eca) is a polysaccharide found on the outer membrane of virtually all gram-negative enteric bacteria and consists of three sugars, n-acetyl-d-glucosamine, n-acetyl-d-mannosaminuronic acid, and 4-acetamido-4,6-dideoxy-d-galactose, organized into trisaccharide repeating units having the sequence -->3)-alpha-d-fuc4nac-(1-->4)-beta-d-mannaca-(1-->4)-alpha-d-glcnac-(1-->. while the precise function of eca is unknown, it has been linked to the resistance of shiga-toxin- ...	2006	16855251
arginine-dependent acid resistance in salmonella enterica serovar typhimurium.	salmonella enterica serovar typhimurium does not survive a ph 2.5 acid challenge under conditions similar to those used for escherichia coli. here, we provide evidence that s. enterica serovar typhimurium can display arginine-dependent acid resistance (ar) provided the cells are grown under anoxic conditions and not under the microaerobic conditions used for assessment of ar in e. coli. the role of the arginine decarboxylase pathway in salmonella ar was shown by the loss of ar in mutants lacking ...	2006	16855258
antibiotic resistance of salmonella enterica serovar paratyphi a in india: emerging and reemerging problem.	antibiotic resistance pattern and r-plasmid of salmonella enterica serovar paratyphi a isolates from kolkata, india are not well documented.	2006	16855314
caspase-1-mediated activation of interleukin-1beta (il-1beta) and il-18 contributes to innate immune defenses against salmonella enterica serovar typhimurium infection.	caspase-1 (casp-1) mediates the processing of the proinflammatory cytokines interleukin-1beta (il-1beta) and il-18 to their mature forms. casp-1-deficient mice succumb more rapidly to salmonella challenge than do wild-type animals. both casp-1 substrates, il-18 and il-1beta, are relevant for control of salmonella enterica serovar typhimurium. we used il-18-/- and il-1beta-/- mice in addition to administration of recombinant il-18 to casp-1-/- mice to demonstrate that il-18 is important for resis ...	2006	16861683
preliminary evaluation of the use of the sefa fimbrial gene to elicit immune response against salmonella enterica serotype enteritidis in chickens.	in the last 2 decades, the prevalence of salmonella enterica serotype enteritidis (salmonella enteritidis) has dramatically increased worldwide, becoming the leading cause of food-borne illnesses and an important public health issue. many studies have suggested the role of the sef14 fimbrial protein in the adhesion of salmonella enteritidis to the host. in the present study, the sefa gene, which encodes the main subunit of the sef14 fimbrial protein, was cloned into a temperature-sensitive expre ...	2006	16863065
protection conferred by a live salmonella enteritidis vaccine against fowl typhoid in laying hens.	fowl typhoid is under control in poultry farms of developed countries, but it still endemically subsists in commercial laying hen farms of some countries. it has been demonstrated that salmonella live vaccines can elicit cross-immunity against members of the same kauffmann-white scheme serogroup. in this work, we explored the protection conferred by tad salmonella vac e, a live salmonella enterica serovar enteritidis vaccine, against fowl typhoid. three groups of laying hens were vaccinated with ...	2006	16863082
influence of eggshell condensation on eggshell penetration and whole egg contamination with salmonella enterica serovar enteritidis.	shells of agar-filled and whole eggs were inoculated with 10(3) to 10(4) cfu of salmonella enterica serovar enteritidis per eggshell. the agar-filled eggs were used to study bacterial eggshell penetration, and the whole egg results were used to characterize contamination of the egg contents. in each group, half of the eggs were stored for 21 days at 20 degrees c and 60% relative humidity (rh), and the other half was stored for 24 h at 6 degrees c and then for 20 days at 20 degrees c. the latter ...	2006	16865883
fate of staphylococcus aureus, salmonella enterica serovar typhimurium, and vibrio vulnificus in raw oysters treated with chitosan.	the fate of staphylococcus aureus, salmonella enterica serovar typhimurium, and vibrio vulnificus in oysters treated with chitosan was investigated. three concentrations (0.5, 1.0, and 2.0%) of chitosan in 0.5% hydrochloric acid were prepared and coated onto raw oysters, which were then stored at 4 degrees c for 12 days. untreated oysters and oysters coated with 0.5% hydrochloric acid without chitosan were used as controls. s. aureus cells were most sensitive to 2.0% chitosan followed by 0.5 and ...	2006	16865892
identification of salmonella enterica serovar typhimurium using specific pcr primers obtained by comparative genomics in salmonella serovars.	salmonella enterica serovar typhimurium is a major foodborne pathogen throughout the world. until now, the specific target genes for the detection and identification of serovar typhimurium have not been developed. to determine the specific probes for serovar typhimurium, the genes of serovar typhimurium lt2 that were expected to be unique were selected with the blast (basic local alignment search tool) program within genbank. the selected genes were compared with 11 genomic sequences of various ...	2006	16865900
adhesion properties and competitive pathogen exclusion ability of bifidobacteria with acquired acid resistance.	the adhesion properties of bifidobacterium longum and bifidobacterium catenulatum strains with an acquired resistance to acid and their ability to competitively exclude salmonella enterica serovar typhimurium, escherichia coli, listeria monocytogenes, enterobacter sakazakii, and clostridium difficile from adhering to human intestinal mucus were evaluated and compared with the results when the same experiments were run with the original acid-sensitive strains. in half of the four studied cases, t ...	2006	16865903
an international outbreak of human salmonellosis associated with animal-derived pet treats--canada and washington state, 2005.		2006	16869066
salmonella enterica serovar typhimurium effectors sopb, sope, sope2 and sipa disrupt tight junction structure and function.	salmonella enterica serovar typhimurium is a major cause of human gastroenteritis. infection of epithelial monolayers by s. typhimurium disrupts tight junctions that normally maintain the intestinal barrier and regulate cell polarity. tight junction disruption is dependent upon the salmonella pathogenicity island-1 (spi-1) type 3 secretion system but the specific effectors involved have not been identified. in this study we demonstrate that sopb, sope, sope2 and sipa are the spi-1-secreted effec ...	2006	16869830
dissemination and persistence of blactx-m-9 are linked to class 1 integrons containing cr1 associated with defective transposon derivatives from tn402 located in early antibiotic resistance plasmids of inchi2, incp1-alpha, and incfi groups.	this study analyzes the diversity of in60, a class 1 integron bearing cr1 and containing bla(ctx-m-9), and its association with tn402, tn21, and classical conjugative plasmids among 45 ctx-m-9-producing clinical strains (41 escherichia coli strains, 2 klebsiella pneumoniae strains, 1 salmonella enterica strain, and 1 enterobacter cloacae strain). forty-five patients in a spanish tertiary care hospital were studied (1996 to 2003). the diversity of in60 and association of in60 with tn402 or mercur ...	2006	16870767
gene-specific effects of antisense phosphorodiamidate morpholino oligomer-peptide conjugates on escherichia coli and salmonella enterica serovar typhimurium in pure culture and in tissue culture.	the objective was to improve efficacy of antisense phosphorodiamidate morpholino oligomers (pmos) by improving their uptake into bacterial cells. four different bacterium-permeating peptides, rffrffrffxb, rtrtrflrrtxb, rxxrxxrxxb, and kffkffkffkxb (x is 6-aminohexanoic acid and b is beta-alanine), were separately coupled to two different pmos that are complementary to regions near the start codons of a luciferase reporter gene (luc) and a gene required for viability (acpp). luc peptide-pmos targ ...	2006	16870773
new integron-associated gene cassette encoding a trimethoprim-resistant dfrb-type dihydrofolate reductase.	a sixth gene cassette containing a dfrb-type gene, dfrb6, was found in a dfrb6-aada1 cassette array in class 1 integrons. this array was isolated from several multiply antibiotic-resistant salmonella enterica serovar infantis strains that appear to be clonally related. the dfrb6 dihydrofolate reductase conferred resistance to trimethoprim.	2006	16870788
qnr prevalence in ceftazidime-resistant enterobacteriaceae isolates from the united states.	we screened 313 ceftazidime-resistant enterobacteriaceae isolates obtained in the united states from 1999 to 2004 for all three known qnr genes. a qnr gene was present in 20% of klebsiella pneumoniae isolates, 31% of enterobacter sp. isolates, and 4% of escherichia coli isolates. qnra and qnrb occurred with equivalent frequencies and, except for qnrb in enterobacters, were stable over time. qnrs was absent.	2006	16870791
maintenance of nitric oxide and redox homeostasis by the salmonella flavohemoglobin hmp.	intracellular pathogens must resist the antimicrobial actions of nitric oxide (no.) produced by host cells. to this end pathogens possess several no.-metabolizing enzymes. here we show that the flavohemoglobin hmp is the principal enzyme responsible for aerobic no. metabolism by salmonella enterica serovar typhimurium. we further show that hmp is required for salmonella virulence in mice, in contrast to s-nitrosoglutathione reductase, flavorubredoxin, or cytochrome c nitrite reductase. abrogatio ...	2006	16873371
molecular typing of salmonella enterica serotype worthington isolates from infantile diarrhoea.	salmonella worthington has been known to be a causative agent for childhood diarrhoea. there is a paucity of information on the molecular relatedness of the strains isolated in various hospitals in india. the present study was carried out to attempt molecular typing of a cluster of salmonella worthington isolates obtained from cases of infantile diarrhoea during a six month period, from a tertiary care paediatric hospital in delhi, india.	2006	16873913
autophagy recognizes intracellular salmonella enterica serovar typhimurium in damaged vacuoles.	autophagy is responsible for the degradation of cytosolic components within eukaryotic cells. interestingly, autophagy also appears to play a role in recognizing invading intracellular pathogens. salmonella enterica serovar typhimurium (s. typhimurium) is an intracellular pathogen that normally resides and replicates within the salmonella-containing vacuole (scv). however, during in vitro infection a population of s. typhimurium damage and escape from the scv to enter the cytosol. we have observ ...	2006	16874057
social stress increases fecal shedding of salmonella typhimurium by early weaned piglets.	"segregated early weaning" (sew) of pigs reduces exposure to pathogenic bacteria, but upon arrival at grower facilities pigs may be co-mingled regardless of farm of origin. the present study was designed to examine the effect of mixing (social) stress on populations of salmonella enterica typhimurium in sew pigs. piglets (7 days old; n = 28 in each of 2 replicates) were separated into 2 treatments (control and mixed groups) of 2 pens per treatment (7 piglets/pen). one (n = 1) "seeder" pig/pen wa ...	2006	16875421
in vitro and in vivo stability of plasmids in attenuated salmonella enterica serovar typhimurium used as a carrier of dna vaccine is associated with its replication origin.	the ability of live attenuated salmonella enterica serovar typhimurium (s. typhimurium) as a carrier of dna vaccine was evaluated using model plasmid encoding beta-galactosidase (beta-gal) and balb/c mice. we constructed pbrcmvbeta, beta-gal expression apparatus having a replication origin from low copy pbr322. comparison of the plasmid stability showed that pbrcmvbeta remained stable in salmonella even after oral administration, while puc-based pcmvbeta tended to be lost quickly. however, titer ...	2006	16880689
isolation of salmonella from environmental samples collected in the reptile department of antwerp zoo using different selective methods.	to evaluate the environmental spread of salmonella strains in the reptile department of antwerp zoo and to compare different isolation methods for salmonella.	2006	16882135
characterization of the enterobacteriaceae isolated from an artisanal italian ewe's cheese (pecorino abruzzese).	to evaluate some physiological characteristics of the enterobacteriaceae isolated from pecorino cheese.	2006	16882142
development of an ultra rapid and simple multiplex polymerase chain reaction technique for detection of salmonella typhi.	to make a rapid and definite diagnosis of salmonella enteritis, using an ultra rapid multiplex polymerase chain reaction (pcr) detection method for major salmonella serotypes, such as salmonella typhi, salmonella typhimurium and salmonella havana.	2006	16883440
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 ...	2006	16884750
fitness of human enteric pathogens on plants and implications for food safety.	the continuous rise in the number of outbreaks of foodborne illness linked to fresh fruit and vegetables challenges the notion that enteric pathogens are defined mostly by their ability to colonize the intestinal habitat. this review describes the epidemiology of produce-associated outbreaks of foodborne disease and presents recently acquired knowledge about the behavior of enteric pathogens on plants, with an emphasis on salmonella enterica, escherichia coli o157:h7, and listeria monocytogenes. ...	2006	16704355
comparative genomics reveals what makes an enterobacterial plant pathogen.	the bacterial family enterobacteriaceae contains some of the most devastating human and animal pathogens, including escherichia coli, salmonella enterica and species of yersinia and shigella. these are among the best-studied of any organisms, yet there is much to be learned about the nature and evolution of interactions with their hosts and with the wider environment. comparative and functional genomics have fundamentally improved our understanding of their modes of adaptation to different ecolo ...	2006	16704357
web-based surveillance and global salmonella distribution, 2000-2002.	salmonellae are a common cause of foodborne disease worldwide. the world health organization (who) supports international foodborne disease surveillance through who global salm-surv and other activities. who global salm-surv members annually report the 15 most frequently isolated salmonella serotypes to a web-based country databank. we describe the global distribution of reported salmonella serotypes from human and nonhuman sources from 2000 to 2002. among human isolates, s. enteritidis was the ...	2006	16704773
molecular analysis of fluoroquinolone-resistant salmonella paratyphi a isolate, india.	salmonella enterica serovar paratyphi a is increasingly a cause of enteric fever. sequence analysis of an indian isolate showed a unique strain with high-level resistance to ciprofloxacin associated with double mutations in the dna gyrase subunit gyra (ser83-->phe and asp87-->gly) and a mutation in topoisomerase iv subunit parc (ser80-->arg).	2006	16704790
aquariums as reservoirs for multidrug-resistant salmonella paratyphi b.	multidrug-resistant salmonella enterica serovar paratyphi b dt+ isolates from patients with gastroenteritis were identical with isolates from their home aquariums. matched isolates had identical phage types, xbai and is200 profiles, and salmonella genomic island 1 (sgi1). ornamental fish tanks are reservoirs for sgi1-containing s. paratyphi b dt+.	2006	16704796
interpreting streptomycin susceptibility test results for salmonella enterica serovar typhimurium.	resistance or susceptibility of salmonella enterica to streptomycin is widely used as an epidemiological marker. however, there is no clear consensus on the interpretation of streptomycin susceptibility test results. comparison of results obtained with the clinical and laboratory standards institute (clsi) disk diffusion method, the minimum inhibitory concentration (mic) determined by etest and streptomycin resistance genotype for 90 isolates of s. enterica serovar typhimurium suggests that appr ...	2006	16704923
chloroquinolines block antibiotic efflux pumps in antibiotic-resistant enterobacter aerogenes isolates.	efflux mechanisms protect bacterial cells by pumping out toxic compounds and actively contribute to bacterial multidrug resistance. agents inhibiting efflux pumps are of interest for the control of multidrug-resistant bacterial infections. herein we report the effects of new chloroquinoline derivatives that render resistant enterobacter aerogenes isolates noticeably more susceptible to structurally unrelated antibiotics. in addition, some of these chloroquinolines increase the intracellular conc ...	2006	16707249
crl activates transcription initiation of rpos-regulated genes involved in the multicellular behavior of salmonella enterica serovar typhimurium.	in salmonella enterica serovar typhimurium, the stationary-phase sigma factor sigma(s) (rpos) is required for virulence, stress resistance, biofilm formation, and development of the rdar morphotype. this morphotype is a multicellular behavior characterized by expression of the adhesive extracellular matrix components cellulose and curli fimbriae. the crl protein of escherichia coli interacts with sigma(s) and activates expression of sigma(s)-regulated genes, such as the csgbac operon encoding th ...	2006	16707690
identification of methylation sites in thermotoga maritima chemotaxis receptors.	adaptation in bacterial chemotaxis involves reversible methylation of specific glutamate residues within the cytoplasmic domains of methyl-accepting chemotaxis proteins. the specific sites of methylation in salmonella enterica and escherichia coli chemoreceptors, identified 2 decades ago, established a consensus sequence for methylation by methyltransferase cher. here we report the in vitro methylation of chemoreceptors from thermotoga maritima, a hyperthermophile that has served as a useful sou ...	2006	16707700
xanthosine utilization in salmonella enterica serovar typhimurium is recovered by a single aspartate-to-glycine substitution in xanthosine phosphorylase.	xapabr from salmonella enterica was analyzed and compared with the corresponding escherichia coli genes. xapb and xapr, but not xapa, encode functional proteins. an s. enterica xapa(asp72gly) mutant that restores the phosphorolytic activity was selected. the purified mutant enzyme has different kinetic constants than the e. coli enzyme but similar substrate specificity.	2006	16707709
induction of the sos response by bacteriophage lytic development in salmonella enterica.	infection of salmonella enterica with lytic mutants of either p22 or se1 bacteriophages triggers the expression of its dna damage-inducible sos response through a lexa-dependent pathway. this induction of the sos system strictly requires the presence of the bacteriophage kil gene. accordingly, plasmid overexpression of the kil gene also promotes the s. enterica sos network induction. furthermore, s. enterica gifsy prophages are induced following the infection with se1 and p22 lytic derivatives. ...	2006	16713610
the genetics of salmonella genomic island 1.	multidrug-resistant salmonella enterica serovar typhimurium phage type dt104, resistant to ampicillin, chloramphenicol/florfenicol, streptomycin, sulfonamides, and tetracycline, has disseminated worldwide. the resistance genes reside on the 43-kb salmonella genomic island 1 (sgi1), which is transferable. drug-resistant variants of sgi1 have been identified in numerous serotypes. strains harboring sgi1 may be more virulent and have a tendency to rapidly disseminate.	2006	16713724
evolution of the virulence plasmids of non-typhoid salmonella and its association with antimicrobial resistance.	among more than 2,500 serovars, eight contain a virulence plasmid, including medically important salmonella enterica serovars choleraesuis, dublin, enteritidis, and typhimurium. these serovar-specific virulence plasmids vary in size, but all contain the spv operon, which plays a role in the expression of the virulence. genetically, these virulence plasmids are likely derived from a common ancestral plasmid possessing virulence-related genes and loci. based on the analysis of the available dna se ...	2006	16713725
emergence of salmonella enterica serotype paratyphi a as a major cause of enteric fever in kathmandu, nepal.	we performed pulsed-field gel electrophoresis (xbai) on 114 bloodstream isolates of salmonella enterica serotype paratyphi a and s. enterica serotype typhi collected from febrile patients in kathmandu, nepal. of the 56 s. paratyphi a isolates, 51 (91%) were indistinguishable, which suggests the emergence of a single clone. in contrast, only 21 (36%) of the 58 s. typhi isolates exhibited a common genotype, which is consistent with endemic disease from multiple sources.	2006	16714040
salmonella resistant to extended-spectrum cephalosporins: prevalence and epidemiology.	salmonella resistant to extended-spectrum cephalosporins (escs) have emerged worldwide since 1988. by 2004, 43 countries had reported this public health problem. resistance was mediated by classical extended-spectrum beta-lactamases, plasmid-mediated cephalosporinases, and recently a class a carbapenemase. of these, cmy-2 is the most widely disseminated enzyme. salmonella enterica serotype typhimurium and s. enterica serotype enteritidis are the most common serovars associated with esc resistanc ...	2006	16714134
salmonella enterica serovar typhimurium requires the lpf, pef, and tafi fimbriae for biofilm formation on hep-2 tissue culture cells and chicken intestinal epithelium.	recent work has demonstrated that salmonella enterica serovar typhimurium forms biofilms on hep-2 tissue culture cells in a type 1 fimbria-dependent manner. to investigate how biofilm growth of hep-2 tissue culture cells affects gene expression in salmonella, we compared global gene expression during planktonic growth and biofilm growth. microarray results indicated that the transcription of approximately 100 genes was substantially altered by growth in a biofilm. these genes encode proteins wit ...	2006	16714543
analyses of five gallinacin genes and the salmonella enterica serovar enteritidis response in poultry.	gallinacins in poultry are functional equivalents of mammalian beta-defensins, which constitute an integral component of the innate immune system. salmonella enterica serovar enteritidis is a gram-negative bacterium that negatively affects both human and animal health. to analyze the association of genetic variations of the gallinacin genes with the phenotypic response to s. enterica serovar enteritidis, an f1 population of chickens was created by crossing four outbred broiler sires to dams of t ...	2006	16714567
multiplication and motility of salmonella enterica serovars enteritidis, infantis, and montevideo in in vitro contamination models of eggs.	the invasive ability of salmonella enterica serovars enteritidis, infantis, and montevideo in eggs was examined. strains of these serovars originating from egg contents, laying chicken houses, and human patients were experimentally inoculated (0.1-ml dose containing 78 to 178 cells) onto the vitelline membrane of eggs collected from specific-pathogen-free chickens and incubated at 25 degrees c. the test strains were detected in 25 of 138 yolk contents by day 6, indicating the penetration of salm ...	2006	16715797
salmonella enterica serotype choleraesuis infections in pediatric patients.	among >2500 nontyphoid salmonella serotypes, salmonella enterica serotype choleraesuis shows a high predilection to cause systemic infections in humans. the objective of this study was to delineate the clinical and microbiologic features of pediatric patients with salmonella choleraesuis infections.	2006	16717121
magnesium transporters: properties, regulation and structure.	the chemistry of mg2+ is unique amongst biological cations, and the properties of mg2+ transport systems reflect this chemistry. prokaryotes carry three classes of mg2+ transport systems: cora, mgta/b and mgte. cora and mgte are widely distributed in both eubacteria and archaea, while the mgta/b class is found primarily in the eubacteria. eukaryotic homologs of cora, although clearly functional as mg2+ transporters, have minimal sequence homology and include the mrs2p mitochondrial mg2+ channel ...	2006	16720382
identification of the plasmid-borne quinolone resistance gene qnrs in salmonella enterica serovar infantis.	a salmonella enterica serovar infantis isolate of avian origin was investigated for the presence of the gene qnrs, its transferability and its association with other resistance genes.	2006	16720566
pcr detection of salmonella spp. using primers targeting the quorum sensing gene sdia.	bacteria communicate with one another and with their host using chemical signalling molecules. this phenomenon is generally described as quorum sensing. a set of primers for pcr detection of salmonella spp. has been designed using as target the sdia gene which encodes a signal receptor of the luxr family. the pcr product (274 bp) was confirmed by sequencing. a number of 81 non-salmonella strains (representing 24 different species) were tested and gave negative results, while a total of 101 diffe ...	2006	16734780
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 ...	2006	16476793
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.	2006	16477547
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.	2006	16478425
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.	2006	16478439
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.	2006	16478509
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 ...	2006	16481212
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 ...	2006	16483621
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.	2006	16484843
[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 ...	2006	16485096
evaluation of the association between feeding raw meat and salmonella enterica infections at a greyhound breeding facility.	to investigate salmonella enterica infections at a greyhound breeding facility.	2006	16677120
rapid and simple detection of food poisoning bacteria by bead assay with a microfluidic chip-based system.	a rapid bead assay for detecting pathogenic bacteria with a simple microfluidic chip-based system was developed. five oligonucleotide probes corresponding to the 16s rrna of the targeted bacteria were coupled covalently to fluorescent beads. four species of bacteria (escherichia coli, salmonella enterica subsp. enterica serovar enteritidis, yersinia enterocolitica, and bacillus cereus) were used as representative food-borne pathogenic bacteria. the rnas extracted from pure cultures of these micr ...	2006	16678290
occurrence of swine salmonellosis in postweaning multisystemic wasting syndrome (pmws) affected pigs concurrently infected with porcine reproduction and respiratory syndrome virus (prrsv).	fourteen diseased pigs from four farms in which there had been an outbreak of salmonellosis were investigated. granulomatous inflammation with depletion of lymphocytes was observed in the swollen lymph nodes in these pigs. antigens to porcine circovirus type 2 (pcv2) were immunolabeled in the lesions along with detection of viral dna as pcv2 by polymerase chain reaction (pcr). in addition, antigens to porcine reproductive respiratory syndrome virus (prrsv) were immunodetected in the lungs and sa ...	2006	16679733
the mammalian ionic environment dictates microbial susceptibility to antimicrobial defense peptides.	antimicrobial peptides (amps) have been shown in animal and human systems to be effective natural antibiotics. however, it is unclear how they convey protection; they often appear inactive when assayed under culture conditions applied to synthetic antibiotics. this inactivation has been associated with loss of function in physiological concentrations of nacl or serum. in this study we show that the balance of host ionic conditions dictate microbial sensitivity to amps. carbonate is identified as ...	2006	16394265