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salmonella enterica serovar typhimurium-induced maturation of bone marrow-derived dendritic cells.murine bone marrow-derived dendritic cells (dc) can phagocytose and process salmonella enterica serovar typhimurium for peptide presentation on major histocompatibility complex class i (mhc-i) and mhc-ii molecules. to investigate if a serovar typhimurium encounter with dc induces maturation and downregulates their ability to present antigens from subsequently encountered bacteria, dc were pulsed with serovar typhimurium 24 h prior to coincubating with escherichia coli expressing the model antige ...200011035740
a novel action of the proton pump inhibitor rabeprazole and its thioether derivative against the motility of helicobacter pylori.the motility of helicobacter pylori was maximum at 37 degrees c and at ph 6. a newly developed proton pump inhibitor, rabeprazole (rpz), and its thioether derivative (rpz-th) markedly inhibited the motility of h. pylori. the concentrations of the drug necessary to inhibit 50% of the motility were 0.25, 16, 16, and >64 microgram/ml for rpz-th, rpz, lansoprazole, and omeprazole, respectively. no such inhibitory effects were observed with h(2) blockers or anti-h. pylori agents. the motilities of ca ...200011036024
evidence for an efflux pump mediating multiple antibiotic resistance in salmonella enterica serovar typhimurium.the mechanism of multiple antibiotic resistance in six isolates of salmonella enterica serovar typhimurium recovered from a patient treated with ciprofloxacin was studied to investigate the role of efflux in the resistance phenotype. compared to the patient's pretherapy isolate (l3), five of six isolates accumulated less ciprofloxacin, three of six isolates accumulated less chloramphenicol, and all six accumulated less tetracycline. the accumulation of one or more antibiotics was increased by ca ...200011036033
biological cost of ampc production for salmonella enterica serotype typhimurium.chromosomally mediated ampc-type beta-lactamases are frequently found among enterobacteriaceae. hyperproduction of ampc beta-lactamase results in high-level resistance to beta-lactam antibiotics. one striking feature of salmonella is the absence of the structural ampc gene, encoding ampc beta-lactamase, in contrast with other members in the enterobacteriaceae family, such as escherichia, citrobacter, or enterobacter. the horizontal acquisition of ampc genes is one of the causes of the increased ...200011036037
competitive exclusion treatment reduces the mortality and fecal shedding associated with enterotoxigenic escherichia coli infection in nursery-raised neonatal pigs.we have previously reported that the administration of a competitive exclusion culture (pcf-1), derived from the cecal microflora of a young, healthy pig and maintained in a continuous flow fermentation system to neonatal pigs resulted in a decrease in the incidence of fecal shedding and cecal colonization by salmonella choleraesuis in pigs at weaning. in the present experiment, we describe the effects of the administration of a derivative of the pcf-1 culture, rpcf, against an enterotoxigenic e ...200011041496
[possibilities for standardization of elisa for detection of salmonella antibodies in sera and meat juices of pigs].programmes for controlling salmonella infections in german piggeries are based on the meat-juice-elisa conducted in various investigation centres by using different test-kits. a usual procedure for harmonization (standardisation) of results is the calculation of the percentage of antibody-concentration from field samples in relation to the extinctions of a set of control-sera with known antibody concentrations. whether this system is still acceptable in case of using different test-kits seems to ...200011042945
a signal transduction system that responds to extracellular iron.iron is essential for all organisms but can be toxic in excess. iron homeostasis is typically regulated by cytoplasmic iron binding proteins, but here we describe a signal transduction system (pmra/pmrb) that responds to extracytoplasmic ferric iron. iron promoted transcription of pmra-activated genes and resistance to the antibiotic polymyxin in salmonella. the pmrb protein bound iron via its periplasmic domain which harbors two copies of the sequence exxe, a motif present in the saccharomyces ...200011051552
genetics of swarming motility in salmonella enterica serovar typhimurium: critical role for lipopolysaccharide.salmonella enterica serovar typhimurium can differentiate into hyperflagellated swarmer cells on agar of an appropriate consistency (0.5 to 0.8%), allowing efficient colonization of the growth surface. flagella are essential for this form of motility. in order to identify genes involved in swarming, we carried out extensive transposon mutagenesis of serovar typhimurium, screening for those that had functional flagella yet were unable to swarm. a majority of these mutants were defective in lipopo ...200011053374
sequence of the genome of salmonella bacteriophage p22.the sequence of the nonredundant region of the salmonella enterica serovar typhimurium temperate, serotype-converting bacteriophage p22 has been completed. the genome is 41,724 bp with an overall moles percent gc content of 47.1%. numerous examples of potential integration host factor and c1-binding sites were identified in the sequence. in addition, five potential rho-independent terminators were discovered. sixty-five genes were identified and annotated. while many of these had been described ...200011053393
transcription initiation-defective forms of sigma(54) that differ in ability to function with a heteroduplex dna template.transcription by sigma(54)-rna polymerase holoenzyme requires an activator that catalyzes isomerization of the closed promoter complex to an open complex. we examined mutant forms of salmonella enterica serovar typhimurium sigma(54) that were defective in transcription initiation but retained core rna polymerase- and promoter-binding activities. four of the mutant proteins allowed activator-independent transcription from a heteroduplex dna template. one of these mutant proteins, l124p v148a, had ...200011053397
molecular analysis of tetracycline resistance in salmonella enterica subsp. enterica serovars typhimurium, enteritidis, dublin, choleraesuis, hadar and saintpaul: construction and application of specific gene probes.a total of 65 epidemiologically unrelated tetracycline-resistant isolates of the six salmonella enterica subsp. enterica (salm.) serovars dublin, choleraesuis, typhimurium, enteritidis, hadar and saintpaul were investigated for the presence of tetracycline resistance genes. for this, specific gene probes of the tetracycline resistance genes (tet) of the hybridization classes a, b, c, d, e and g were constructed by cloning pcr-amplified internal segments of the respective tet structural genes. th ...200011054167
characterization and chromosomal mapping of antimicrobial resistance genes in salmonella enterica serotype typhimurium.two hundred and twenty-six salmonella enterica serotype typhimurium isolates were examined for the presence of integron-associated gene cassettes. all but two of the non-dt104 isolates, together with dt104 isolates, contained gene cassettes. amplicons of 1.5 kbp each were found in two non-dt104 isolates, encoding a dhfri gene (trimethoprim resistance) linked to an aada gene (streptomycin and spectinomycin resistance), by site-specific recombination. dt104 isolates of resistance (r) type acssut p ...200011055933
resistance to ceftriaxone and cefotaxime in non-typhoidal salmonella enterica in england and wales, 1998-99. 200011062222
rapid detection of salmonella enterica serovar choleraesuis in blood cultures by a dot blot enzyme-linked immunosorbent assay.a dot blot enzyme-linked immunosorbent assay (elisa) with a monoclonal antibody specific to phase1-c salmonella was developed for the direct detection of salmonella enterica serovar choleraesuis in blood cultures. this system was applied to the identification of serovar choleraesuis, and the results were compared with those obtained by a conventional biochemical method. it was revealed that all 12 samples identified to be infected with serovar choleraesuis were positive on testing by the elisa. ...200011063509
application of randomly amplified polymorphic dna (rapd) analysis for typing avian salmonella enterica subsp. enterica.randomly amplified polymorphic dna (rapd) analysis was performed for the molecular genetic typing of 30 salmonella enterica subsp. enterica strains isolated from chickens and ducks in thailand. six different primers were tested for their discriminatory ability. while some of the primers could only differentiate between the different serovars, the use of multiple primers showed that the rapd method could also subdivide within a given serovar. the ready-to-go rapd analysis beads used, resulted in ...200011064269
identification of soxs-regulated genes in salmonella enterica serovar typhimurium.salmonella enterica serovar typhimurium responds to superoxide-generating agents through soxr-mediated activation of the soxs gene, whose product, soxs, is necessary for resistance to oxidative stress. the s. enterica serovar typhimurium soxrs system also mediates redox-inducible resistance to diverse antibiotics, which may be relevant to clinical infections. in order to identify soxs-regulated genes in s. enterica serovar typhimurium, a laci-regulated expression system for the s. enterica serov ...200010613858
proline catabolism by pseudomonas putida: cloning, characterization, and expression of the put genes in the presence of root exudates.pseudomonas putida kt2442 is a root-colonizing strain which can use proline, one of the major components in root exudates, as its sole carbon and nitrogen source. a p. putida mutant unable to grow with proline as the sole carbon and nitrogen source was isolated after random mini-tn5-km mutagenesis. the mini-tn5 insertion was located at the puta gene, which is adjacent to and divergent from the putp gene. the puta gene codes for a protein of 1,315 amino acid residues which is homologous to the pu ...200010613867
lesions in the nuo operon, encoding nadh dehydrogenase complex i, prevent purf-independent thiamine synthesis and reduce flux through the oxidative pentose phosphate pathway in salmonella enterica serovar typhimurium.in salmonella enterica serovar typhimurium, purf-independent thiamine synthesis (or alternative pyrimidine biosynthesis) allows strains, under some growth conditions, to synthesize thiamine in the absence of the first step in the purine biosynthetic pathway. mutations have been isolated in a number of loci that prevent this synthesis and thus result in an apb(-) phenotype. here we identify a new class of mutations that prevent purf-independent thiamine synthesis and show that they are defective ...200010613887
reduced flux through the purine biosynthetic pathway results in an increased requirement for coenzyme a in thiamine synthesis in salmonella enterica serovar typhimurium.work presented here establishes a connection between cellular coenzyme a (coa) levels and thiamine biosynthesis in salmonella enterica serovar typhimurium. prior work showed that pane mutants (pane encodes ketopantoate reductase) had a conditional requirement for thiamine or pantothenate. data presented herein show that the nutritional requirement of pane mutants for either thiamine or pantothenate is manifest only when flux through the purine biosynthetic pathway is reduced. further, the data s ...200010613889
molecular methods for the epidemiological typing of salmonella enterica serotype typhi from hong kong and vietnam.a total of 217 and 73 strains of salmonella enterica serotype typhi isolated from 1985 to 1997 in hong kong and in 2 months of 1989 and 1990 in vietnam, respectively, were studied. these isolates were typed by plasmid profile analysis, plasmid fingerprinting, ribotyping with psti, and total dna fingerprinting with nari. there appeared to be no major outbreak of typhoid fever in hong kong during the study period since there was considerable heterogeneity among the isolates. isolates from hong kon ...200010618104
evolutionary reversals during viral adaptation to alternating hosts.experimental adaptation of the bacteriophage phix174 to a salmonella host depressed its ability to grow on the traditional escherichia host, whereas adaptation to escherichia did not appreciably affect growth on salmonella. continued host switching consistently exhibited this pattern. growth inhibition on escherichia resulted from two to three substitutions in the major capsid gene. when these phages were forced to grow again on escherichia, fitness recovery occurred predominantly by reversions ...200010628966
the rfae gene from escherichia coli encodes a bifunctional protein involved in biosynthesis of the lipopolysaccharide core precursor adp-l-glycero-d-manno-heptose.the intermediate steps in the biosynthesis of the adp-l-glycero-d-manno-heptose precursor of inner core lipopolysaccharide (lps) are not yet elucidated. we isolated a mini-tn10 insertion that confers a heptoseless lps phenotype in the chromosome of escherichia coli k-12. the mutation was in a gene homologous to the previously reported rfae gene from haemophilus influenzae. the e. coli rfae gene was cloned into an expression vector, and an in vitro transcription-translation experiment revealed a ...200010629197
the amino terminus of salmonella enterica serovar typhimurium sigma(54) is required for interactions with an enhancer-binding protein and binding to fork junction dna.transcription initiation by the sigma(54)-rna polymerase holoenzyme requires an enhancer-binding protein that is thought to contact sigma(54) to activate transcription. to identify potential enhancer-binding protein contact sites in sigma(54), we compared the abilities of wild-type and truncated forms of salmonella enterica serovar typhimurium sigma(54) to interact with the enhancer-binding protein dctd in a chemical cross-linking assay. removal of two regions in the amino-terminal portion of si ...200010629201
opda, a salmonella enterica serovar typhimurium gene encoding a protease, is part of an operon regulated by heat shock.the opda (prlc) gene of salmonella enterica serovar typhimurium and escherichia coli encodes the metalloprotease oligopeptidase a (opda). we report that opda is cotranscribed with a downstream open reading frame, yhiq. transcription of this operon is induced after a temperature shift (30 to 42 degrees c), and this induction depends on the heat shock sigma factor encoded by the rpoh (htpr) gene.200010629202
expression and immunogenicity of hemagglutinin a from porphyromonas gingivalis in an avirulent salmonella enterica serovar typhimurium vaccine strain.porphyromonas gingivalis is a major etiologic agent of periodontitis, a chronic inflammatory disease that ultimately results in the loss of the supporting tissues of the teeth. previous work has demonstrated the usefulness of avirulent salmonella enterica serovar typhimurium strains as antigen delivery systems for protective antigens of pathogens that colonize or cross mucosal surfaces. in this study, we constructed and characterized a recombinant s. enterica serovar typhimurium avirulent vaccin ...200010639440
impact of heterogeneity within cultured cells on bacterial invasion: analysis of pseudomonas aeruginosa and salmonella enterica serovar typhi entry into mdck cells by using a green fluorescent protein-labelled cystic fibrosis transmembrane conductance regulator receptor.the cystic fibrosis transmembrane conductance regulator (cftr) is a chloride ion channel that also serves as a receptor for entry of pseudomonas aeruginosa and salmonella enterica serovar typhi into epithelial cells. to evaluate heterogeneity in cftr protein expression in cultured cells and the effect of heterogeneity on internalization of different p. aeruginosa and serovar typhi strains, we used two-color flow cytometry and confocal laser microscopy to study bacterial uptake by madin-darby can ...200010639456
use of lambda phage s and r gene products in an inducible lysis system for vibrio cholerae- and salmonella enterica serovar typhimurium-based dna vaccine delivery systems.novel methods for adapting dna vaccine technology to the prevention of mucosal diseases are greatly needed. here we show that regulated expression of phage lambda lysis genes s and r causes dramatic lysis of both vibrio cholerae and salmonella enterica serovar typhimurium cells with concomitant release of plasmid dna into the surrounding media. we also used single and double dnase mutant strains to show that secreted v. cholerae dnases can adversely affect the integrity of dna molecules released ...200010639478
the salmonella yopj-homologue avra does not possess yopj-like activity.the yopj protein of yersinia pseudotuberculosis inhibits several eukaryotic signalling pathways that are normally activated in cells following their contact with bacteria. salmonella encodes a protein, avra, that is secreted by the typeiii inv/spa secretion system which is clearly homologous to yopj (56% identical, 87% similarity). since avra and yopjs similarity also encompassed a region of yopj that had previously been shown to be critical for its biological activity, we were interested whethe ...200010644492
genetic and biochemical characterization of salmonella enterica serovar typhi deoxyribokinase.we identified in the genome of salmonella enterica serovar typhi the gene encoding deoxyribokinase, deok. two other genes, vicinal to deok, were determined to encode the putative deoxyribose transporter (deop) and a repressor protein (deoq). this locus, located between the uhpa and ilvn genes, is absent in escherichia coli. the deok gene inserted on a plasmid provides a selectable marker in e. coli for growth on deoxyribose-containing medium. deoxyribokinase is a 306-amino-acid protein which exh ...200010648508
prpr, ntra, and ihf functions are required for expression of the prpbcde operon, encoding enzymes that catabolize propionate in salmonella enterica serovar typhimurium lt2.the genes required for the catabolism of propionate in salmonella enterica serovar typhimurium are organized as two transcriptional units (prpr and prpbcde) that are divergently transcribed from one another. sequence homology to genes encoding members of the sigma-54 family of transcriptional activators and the identification of a consensus sigma-54 promoter 5' to the prpbcde operon suggested that prpr was required to activate expression of this operon. we isolated insertions in prpr and showed ...200010648513
insertional inactivation of genes encoding components of the sodium-type flagellar motor and switch of vibrio parahaemolyticus.vibrio parahaemolyticus possesses two types of flagella, polar and lateral, powered by distinct energy sources, which are derived from the sodium and proton motive forces, respectively. although proton-powered flagella in escherichia coli and salmonella enterica serovar typhimurium have been extensively studied, the mechanism of torque generation is still not understood. molecular knowledge of the structure of the sodium-driven motor is only now being developed. in this work, we identify the swi ...200010648530
fragmentation of 23s rrna in strains of proteus and providencia results from intervening sequences in the rrn (rrna) genes.intervening sequences (ivss) were originally identified in the rrl genes for 23s rrna (rrl genes, for large ribosomal subunit, part of rrn operon encoding rrna) of salmonella enterica serovars typhimurium lt2 and arizonae. these sequences are transcribed but later removed during rnase iii processing of the rrna, resulting in fragmentation of the 23s species; ivss are uncommon, but have been reported in at least 10 bacterial genera. through pcr amplification of ivs-containing regions of the rrl g ...200010648538
genetically modified vibrio harveyi strains as potential bioindicators of mutagenic pollution of marine environments.for biodetection of mutagenic pollution of marine environments, an organism naturally occurring in these habitats should be used. we found that marine bacterium vibrio harveyi may be an appropriate bioindicator of mutagenic pollution. for positive selection of mutants, we developed a simple method for isolation of v. harveyi mutants resistant to neomycin. we constructed genetically modified v. harveyi strains that produce significantly more neomycin-resistant mutants upon treatment with low conc ...200010653723
molecular characterization of irish salmonella enterica serotype typhimurium: detection of class i integrons and assessment of genetic relationships by dna amplification fingerprinting.salmonella enterica is among the principal etiological agents of food-borne illness in humans. increasing antimicrobial resistance in s. enterica is a cause for worldwide concern. there is concern at present in relation to the increasing incidence of human infection with antimicrobial agent-resistant strains of s. enterica serotype typhimurium, in particular of phage type dt104. integrons appear to play an important role in the dissemination of antimicrobial resistance genes in many enterobacter ...200010653725
epidemic typhoid in vietnam: molecular typing of multiple-antibiotic-resistant salmonella enterica serotype typhi from four outbreaks.multidrug-resistant salmonella enterica serotype typhi isolates from four outbreaks of typhoid fever in southern vietnam between 1993 and 1997 were compared. pulsed-field gel electrophoresis, bacteriophage and plasmid typing, and antibiotic susceptibilities showed that independent outbreaks of multidrug-resistant typhoid fever in southern vietnam are caused by single bacterial strains. however, different outbreaks do not derive from the clonal expansion of a single multidrug-resistant serotype t ...200010655411
a role for salmonella fimbriae in intraperitoneal infections.enteric bacteria possess multiple fimbriae, many of which play critical roles in attachment to epithelial cell surfaces. sef14 fimbriae are only found in salmonella enterica serovar enteritidis (s. enteritidis) and closely related serovars, suggesting that sef14 fimbriae may affect serovar-specific virulence traits. despite evidence that sef14 fimbriae are expressed by s. enteritidis in vivo, previous studies showed that sef14 fimbriae do not mediate adhesion to the intestinal epithelium. theref ...200010655518
antimicrobial activity of home disinfectants and natural products against potential human pathogens.to assess the efficacy of both natural products (vinegar, baking soda) and common commercial disinfectants (vesphene iise, tbq, clorox, lysol disinfectant spray, lysol antibacterial kitchen cleaner, mr. clean ultra, ethanol) designed for home or institutional use against potential human pathogens, including selected antibiotic-resistant bacteria.200010656352
the purification, crystallization and structural elucidation of dtdp-d-glucose 4,6-dehydratase (rmlb), the second enzyme of the dtdp-l-rhamnose synthesis pathway from salmonella enterica serovar typhimurium.dtdp-d-glucose 4,6-dehydratase (rmlb) is the second of four enzymes involved in the dtdp-l-rhamnose pathway and catalyzes the dehydration of dtdp-d-glucose to dtdp-4-keto-6-deoxy-d-glucose. the ultimate product of the pathway, dtdp-l-rhamnose, is the precursor of l-rhamnose, which is a key component of the cell wall of many pathogenic bacteria. rmlb from salmonella enterica serovar typhimurium has been overexpressed and purified, and crystals of the enzyme have been grown using the sitting-drop ...200010666612
salmonella enteritidis fimbriae displaying a heterologous epitope reveal a uniquely flexible structure and assembly mechanism.two distinct salmonella fimbrins, agfa and sefa, comprising thin aggregative fimbriae sef17 and sef14, respectively, were each genetically engineered to carry pt3, an alpha-helical 16-amino acid leishmania t-cell epitope derived from the metalloprotease gp63. to identify regions within agfa and sefa fimbrins amenable to replacement with this epitope, pcr-generated chimeric fimbrin genes were constructed and used to replace the native chromosomal agfa and sefa genes in salmonella enteritidis. imm ...200010669594
novel missense mutations that affect the transport function of malk, the atp-binding-cassette subunit of the salmonella enterica serovar typhimurium maltose transport system.we report on novel mutations in the malk gene of salmonella enterica serovar typhimurium, encoding the atpase subunit of the maltose transporter (malfgk(2)). biochemical analysis suggests that (i) l86 might be involved in a signaling step during substrate translocation and (ii) e306 may be critical for the structural integrity of the protein.200010671470
mutational analysis of ligand recognition by tcp, the citrate chemoreceptor of salmonella enterica serovar typhimurium.the chemoreceptor tcp mediates taxis to citrate. to identify citrate-binding residues, we substituted cysteine for seven basic or polar residues that are chosen based on the comparison of tcp with the well-characterized chemoreceptors. the results suggest that arg-63, arg-68, arg-72, lys-75, and tyr-150 (and probably other unidentified residues) are involved in the recognition of citrate.200010671471
solvent accessibility and purifying selection within proteins of escherichia coli and salmonella enterica.the neutral theory of molecular evolution predicts that variation within species is inversely related to the strength of purifying selection, but the strength of purifying selection itself must be related to physical constraints imposed by protein folding and function. in this paper, we analyzed five enzymes for which polymorphic sequence variation within escherichia coli and/or salmonella enterica was available, along with a protein structure. single and multivariate logistic regression models ...200010677853
differential bacterial survival, replication, and apoptosis-inducing ability of salmonella serovars within human and murine macrophages.salmonella serovars are associated with human diseases that range from mild gastroenteritis to host-disseminated enteric fever. human infections by salmonella enterica serovar typhi can lead to typhoid fever, but this serovar does not typically cause disease in mice or other animals. in contrast, s. enterica serovar typhimurium and s. enterica serovar enteritidis, which are usually linked to localized gastroenteritis in humans and some animal species, elicit a systemic infection in mice. to bett ...200010678900
salmonella enterica serovar typhimurium sura mutants are attenuated and effective live oral vaccines.a previously described attenuated tnphoa mutant (brd441) of salmonella enterica serovar typhimurium c5 (i. miller, d. maskell, c. hormaeche, k. johnson, d. pickard, and g. dougan, infect. immun. 57:2758-2763, 1989) was characterized, and the transposon was shown to be inserted in sura, a gene which encodes a peptidylprolyl-cis, trans-isomerase. a defined sura deletion mutation was introduced into s. enterica serovar typhimurium c5 and the mutant strain, named s. enterica serovar typhimurium brd1 ...200010678914
phase 2 clinical trial of attenuated salmonella enterica serovar typhi oral live vector vaccine cvd 908-htra in u.s. volunteers.salmonella enterica serovar typhi strain cvd 908-htra is a live attenuated strain which may be useful as an improved oral typhoid vaccine and as a vector for cloned genes of other pathogens. we conducted a phase 2 trial in which 80 healthy adults received one of two dosage levels of cvd 908-htra in a double-blind, placebo-controlled, crossover study. there were no differences in the rates of side effects among volunteers who received high-dose vaccine (4.5 x 10(8) cfu), lower-dose vaccine (5 x 1 ...200010678926
phase 1 and phase 2 studies of salmonella enterica serovar paratyphi a o-specific polysaccharide-tetanus toxoid conjugates in adults, teenagers, and 2- to 4-year-old children in vietnam.salmonella enterica serovar paratyphi a o-specific polysaccharide (o-sp) was activated with 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (cdap) and bound to tetanus toxoid (tt) with adipic acid dihydrazide as a linker (spa-tt(1)) or directly (spa-tt(2)). in mice, these two conjugates elicited high levels of immunoglobulin g (igg) anti-lipopolysaccharide (lps) in serum with bactericidal activity (e. konadu, j. shiloach, d. a. bryla, j. b. robbins, and s. c. szu, infect. immun. 64:2709-2715 ...200010678970
construction and characterization of a salmonella enterica serovar typhimurium clone expressing a salivary adhesin of streptococcus mutans under control of the anaerobically inducible nirb promoter.attenuated salmonella enterica serovar typhimurium has been used for targeted delivery of recombinant antigens to the gut-associated lymphoid tissues. one potential problem associated with this vaccine approach is the likelihood of in vivo instability of the plasmid constructs caused by constitutive hyperexpression of the heterologous immunogen. the aim of this study was to generate and characterize an expression system encoding the saliva-binding region (sbr) of streptococcus mutans antigen i/i ...200010678973
antibacterial efficacy of gentamicin encapsulated in ph-sensitive liposomes against an in vivo salmonella enterica serovar typhimurium intracellular infection model.encapsulation of gentamicin in liposomes can be used to achieve intracellular delivery and broaden the clinical utility of this drug. we have previously described a novel, rationally designed, ph-sensitive liposomal carrier for gentamicin that has superior in vitro efficacy against intracellular infections compared to the efficacies of both free gentamicin and non-ph-sensitive liposomal controls. this liposomal carrier demonstrated ph-sensitive fusion that was dependent on the presence of unsatu ...200010681314
antibacterial activity of diospyrin, isodiospyrin and bisisodiospyrin from the root of diospyros piscatoria (gurke) (ebenaceae).two dimeric naphthoquinones, diospyrin and isodiospyrin, isolated from the root of diospyros piscatoria (gurke), a common ingredient in several folk medicines, have been shown to have a broad spectrum of antibacterial activity. the minimum inhibitory concentrations (mics) of diospyrin against streptococcus pyogenes atcc 12344 and streptococcus pneumoniae atcc 33400 ranged from 1.56 to 50 microg/ml. while those against salmonella choleraesuis serotype typhi (s. typhi), atcc 6539 and mycobacterium ...200010685108
ssra (tmrna) plays a role in salmonella enterica serovar typhimurium pathogenesis.escherichia coli ssra encodes a small stable rna molecule, tmrna, that has many diverse functions, including tagging abnormal proteins for degradation, supporting phage growth, and modulating the activity of dna binding proteins. here we show that ssra plays a role in salmonella enterica serovar typhimurium pathogenesis and in the expression of several genes known to be induced during infection. moreover, the phage-like attachment site, attl, encoded within ssra, serves as the site of integratio ...200010692360
specificity mutants of the binding protein of the oligopeptide transport system of lactococcus lactis.the kinetic properties of wild-type and mutant oligopeptide binding proteins of lactococcus lactis were determined. to observe the properties of the mutant proteins in vivo, the oppa gene was deleted from the chromosome of l. lactis to produce a strain that was totally defective in oligopeptide transport. amplified expression of the oppa gene resulted in an 8- to 12-fold increase in oppa protein relative to the wild-type level. the amplified expression was paralleled by increased bradykinin bind ...200010692365
antagonistic activity of lactobacillus acidophilus lb against intracellular salmonella enterica serovar typhimurium infecting human enterocyte-like caco-2/tc-7 cells.to gain further insight into the mechanism by which lactobacilli develop antimicrobial activity, we have examined how lactobacillus acidophilus lb inhibits the promoted cellular injuries and intracellular lifestyle of salmonella enterica serovar typhimurium sl1344 infecting the cultured, fully differentiated human intestinal cell line caco-2/tc-7. we showed that the spent culture supernatant of strain lb (lb-scs) decreases the number of apical serovar typhimurium-induced f-actin rearrangements i ...200010698785
development of a nonantibiotic dominant marker for positively selecting expression plasmids in multivalent salmonella vaccines.we report the novel application of a herbicide-resistance-based dominant marker for the positive selection of expression plasmids in salmonella serovar vaccines. the beta-lactamase gene of the plasmid ptetnir15, which expresses fragment c of tetanus toxin (tetc), has been replaced with the bar gene marker. the new plasmid pbat1 can be positively selected in vitro within salmonella serovars in the presence of the herbicide dl-phosphinothricin. the expression of tetc remains unaltered, and the sal ...200010698796
diagnostic and public health dilemma of lactose-fermenting salmonella enterica serotype typhimurium in cattle in the northeastern united states.the presence of lactose-fermenting salmonella strains in clinical case materials presented to microbiology laboratories presents problems in detection and identification. failure to detect these strains also presents a public health problem. the laboratory methods used in detecting lactose-fermenting salmonella enterica serotype typhimurium from six outbreaks of salmonellosis in veal calves are described. each outbreak was caused by a multiply-resistant and lactose-fermenting strain of s. enteri ...200010699026
multiple clones within multidrug-resistant salmonella enterica serotype typhimurium phage type dt104. the greek nontyphoidal salmonella study group.six distinct clones were present among greek multidrug-resistant salmonella enterica serotype typhimurium phage type dt104, since isolates belonging to resistance phenotypes including the acssut (ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline) core could be distinguished with respect to their pulsed-field gel electrophoresis patterns, int1 integron structures, and presence or absence of antibiotic resistance genes ant(3'')-ia, pse-1, and tem-1.200010699039
multidrug-resistant salmonella enterica serotype typhimurium dt104. 200010702060
improved repetitive-element pcr fingerprinting of salmonella enterica with the use of extremely elevated annealing temperatures.modified thermal cycling conditions were explored in an effort to improve the reproducibility and resolving power of repetitive-element pcr (rep-pcr) fingerprinting. assay performance was rigorously evaluated under standard and modified cycling conditions, using as a test set 12 strains putatively representing 12 serovars of salmonella enterica. for all three fingerprint types (eric2, boxa1r, and composite fingerprints), the use of extremely elevated annealing temperatures plus an initial "touch ...200010702502
clinical application of a dot blot test for diagnosis of enteric fever due to salmonella enterica serovar typhi in patients with typhoid fever from colombia and peru.clinical application of a dot blot test to detect immunoglobulin g (igg) (88% sensitivity and specificity) and igm (12.1% sensitivity and 97% specificity) against flagellar antigen from salmonella enterica serovar typhi was performed in peruvian and colombian patients with typhoid fever. this test can be used as a good predictor of serovar typhi infection in regions lacking laboratory facilities and in field studies.200010702512
synergism between porcine reproductive and respiratory syndrome virus (prrsv) and salmonella choleraesuis in swine.porcine reproductive and respiratory syndrome virus (prrsv) and salmonella choleraesuis are two leading causes of economic loss in the swine industry. while respiratory disease is common in both s. choleraesuis and prrsv infections, the factors that contribute to its development remain largely undefined. we investigated the interaction of prrsv, s. choleraesuis, and stress in 5-week-old swine. all combinations of three factors (inoculation with s. choleraesuis on day 0, prrsv on day 3, and treat ...200010703702
prevalence of enteric zoonotic organisms in cats.to determine prevalence of enteric zoonotic organisms in cats in north-central colorado.200010707683
infections and intoxications associated with animal feed and forage which may present a hazard to human health.animal feed or forage may be the source of a limited number of infections for farm animals that could lead to human illness. likely organisms include salmonella enterica, toxoplasma gondii, trichinella spiralis and possibly the agent of bovine spongiform encephalopathy. the risk to human health from other infectious agents which may contaminate either feed or forage appear to be either negligible, e.g. bacillus anthracis and mycobacterium bovis, or non-existent, e.g. clostridium botulinum toxin ...200010712800
multiple factors independently regulate hila and invasion gene expression in salmonella enterica serovar typhimurium.hila activates the expression of salmonella enterica serovar typhimurium invasion genes. to learn more about regulation of hila, we isolated tn5 mutants exhibiting reduced hila and/or invasion gene expression. in addition to expected mutations, we identified tn5 insertions in psts, fadd, flhd, flhc, and flia. analysis of the psts mutant indicates that hila and invasion genes are repressed by the response regulator phob in the absence of the pst high-affinity inorganic phosphate uptake system. th ...200010714991
isolation and characterization of vich, encoding a new pleiotropic regulator in vibrio cholerae.during the last decade, the hns gene and its product, the h-ns protein, have been extensively studied in escherichia coli. h-ns-like proteins seem to be widespread in gram-negative bacteria. however, unlike in e. coli and in salmonella enterica serovar typhimurium, little is known about their role in the physiology of those organisms. in this report, we describe the isolation of vich, an hns-like gene in vibrio cholerae, the etiological agent of cholera. this gene was isolated from a v. cholerae ...200010715012
a community--wide outbreak of salmonella enterica serotype typhimurium infection associated with eating a raw milk soft cheese in france.in 1997, a community-wide outbreak of salmonella enterica serotype typhimurium (s. typhimurium) infection occurred in france. the investigation included case searching and a case-control study. a case was defined as a resident of the jura district with fever or diarrhoea between 12 may and 8 july 1997, from whom s. typhimurium was isolated in stool or blood. one hundred and thirteen cases were identified. thirty-three (83 %) of 40 cases but only 23 (55 %) of 42 community controls, matched for ag ...200010722123
serum amyloid p component bound to gram-negative bacteria prevents lipopolysaccharide-mediated classical pathway complement activation.although serum amyloid p component (sap) is known to bind many ligands, its biological function is not yet clear. recently, it was demonstrated that sap binds to lipopolysaccharide (lps). in the present study, sap was shown to bind to gram-negative bacteria expressing short types of lps or lipo-oligosaccharide (los), such as salmonella enterica serovar copenhagen re and escherichia coli j5, and also to clinical isolates of haemophilus influenzae. it was hypothesized that sap binds to the bacteri ...200010722560
pilot study of phop/phoq-deleted salmonella enterica serovar typhimurium expressing helicobacter pylori urease in adult volunteers.attenuated salmonella enterica serovar typhi has been studied as an oral vaccine vector. despite success with attenuated s. enterica serovar typhimurium vectors in animals, early clinical trials of s. enterica serovar typhi expressing heterologous antigens have shown that few subjects have detectable immune responses to vectored antigens. a previous clinical study of phop/phoq-deleted s. enterica serovar typhi expressing helicobacter pylori urease from a multicopy plasmid showed that none of eig ...200010722611
sequence variation of the 16s to 23s rrna spacer region in salmonella enterica.the possibility for identification of salmonella enterica serotypes by sequence analysis of the 16s to 23s rrna internal transcribed spacer was investigated by direct sequencing of polymerase chain reaction-amplified dna from all operons simultaneously in a collection of 25 strains of 18 different serotypes of s. enterica, and by sequencing individual cloned operons from a single strain. it was only possible to determine the first 117 bases upstream from the 23s rrna gene by direct sequencing be ...200010724482
supplement 1998 (no. 42) to the kauffmann-white scheme.this supplement reports the characterization of 14 new salmonella serovars recognized in 1998 by the who collaborating centre for reference and research on salmonella: 11 were assigned to s. enterica subsp. enterica, one to subspecies salamae, one to subspecies diarizonae, and one to subsp. indica. in addition, the antigenic factor h:z88 is described.200010724485
kinetics of the mucosal antibody secreting cell response and evidence of specific lymphocyte migration to the lung after oral immunisation with attenuated s. enterica var. typhimurium.the kinetic of mucosal secretory responses elicited by the vaccine vector salmonella enterica var. typhimurium (s. typhimurium) was examined by enzyme linked immunospot (elispot) and compared with serum responses. mice immunised orally with brd509, the aroa, arod mutant of virulent s. typhimurium sl1344 expressing the c fragment of tetanus toxin (tt), simultaneously developed an iga antibody secreting cells (asc) response in the gastrointestinal lamina propria, the spleen and the lung, against b ...200010727882
the structure of the linkage between the o-specific polysaccharide and the core region of the lipopolysaccharide from salmonella enterica serovar typhimurium revisited.salmonella enterica sv. typhimurium strain 1135 possesses smooth(s)-form lipopolysaccharide (lps). although the structures of the core region and the o-specific polysaccharide were investigated intensively between the 1960s and the 1980s, the structure of the linkage region between the o-chain and the core was not elucidated unequivocally. by using modern ms and high-field nmr spectroscopy for analysis of the isolated carbohydrate backbone of the lps, it has been shown that it is a beta-d-galp r ...200010727941
an rna transcription-based amplification technique (nasba) for the detection of viable salmonella enterica.possession of mrna is indicative of cell viability. rtpcr is not appropriate for mrna detection as it cannot unambiguously detect mrna in a dna background. the alternative amplification technique, nasba, avoids the disadvantages of rtpcr. we have devised a method for detection of viable salmonella enterica. this involves nasba amplification of mrna transcribed from the dnak gene. amplification of mrna extracted from viable and heat-killed cells from the same population produced consistent and hi ...200010728566
evaluation of a novel enzyme-linked immunosorbent assay for detection of antibodies against salmonella, employing a stable coating of lipopolysaccharide-derived antigens covalently attached to polystyrene microwells.polysaccharides derived from salmonella typhimurium lipopolysaccharide (lps) representing the o-antigen factors 1, 4, 5, and 12 and the o-antigen factors 6 and 7 from salmonella choleraesuis lps were derivatized with the photoreactive compound anthraquinone and subsequently covalently coupled to microtiter polystyrene plates by ultraviolet irradiation. both polysaccharide antigens could be coupled simultaneously to the same microtiter plate. the coated surface was used in indirect elisa for the ...200010730941
the effects of dietary mannaoligosaccharides on cecal parameters and the concentrations of enteric bacteria in the ceca of salmonella-challenged broiler chicks.the ability of different enteric pathogens and coliforms to trigger agglutination of yeast cells (saccharomyces cerevisiae, ncyc 1026) and a yeast cell wall preparation (mos) was examined. five of seven strains of escherichia coli and 7 of 10 strains of salmonella typhimurium and salmonella enteritidis agglutinated mos and sac. cerevisiae cells. strains of salmonella choleraesuis, salmonella pullorum, and campylobacter did not lead to agglutination. two strains that agglutinated mos (s. typhimur ...200010735748
ompr regulates the stationary-phase acid tolerance response of salmonella enterica serovar typhimurium.tolerance to acidic environments is an important property of free-living and pathogenic enteric bacteria. salmonella enterica serovar typhimurium possesses two general forms of inducible acid tolerance. one is evident in exponentially growing cells exposed to a sudden acid shock. the other is induced when stationary-phase cells are subjected to a similar shock. these log-phase and stationary-phase acid tolerance responses (atrs) are distinct in that genes identified as participating in log-phase ...200010735868
complex function for sica, a salmonella enterica serovar typhimurium type iii secretion-associated chaperone.salmonella enterica encodes a type iii secretion system within a pathogenicity island located at centisome 63 that is essential for virulence. all type iii secretion systems require the function of a family of low-molecular-weight proteins that aid the secretion process by acting as partitioning factors and/or secretion pilots. one such protein is sica, which is encoded immediately upstream of the type iii secreted proteins sipb and sipc. we found that the absence of sica results in the degradat ...200010735870
identification of sope2, a salmonella secreted protein which is highly homologous to sope and involved in bacterial invasion of epithelial cells.type iii secreted sop protein effectors are delivered into target eukaryotic cells and elicit cellular responses underlying salmonella pathogenicity. in this work, we have identified another secreted protein, sope2, and showed that sope2 is an important invasion-associated effector. sope2 is encoded by the sope2 gene which is present and conserved in pathogenic strains of salmonella. sope2 is highly homologous to sope, a protein encoded by a gene within a temperate bacteriophage and present in o ...200010735884
differentiation of salmonella enterica serotype gallinarum biotype pullorum from biotype gallinarum by analysis of phase 1 flagellin c gene (flic).salmonella enterica serotype gallinarum biotype gallinarum and biotype pullorum are non-motile and pathogenic avian strains. biotype gallinarum causes fowl typhoid and biotype pullorum is the cause of pullorum disease in chickens. the two biotypes could be differentiated based on biochemical characteristics. however, conventional culture and biochemical assays are time-consuming, laborious and need sterile laboratory practices. although the two biotypes, gallinarum and pullorum are non-motile, t ...200010739340
dual role for macrophages in vivo in pathogenesis and control of murine salmonella enterica var. typhimurium infections.salmonella spp. are regarded as facultative intracellular bacterial pathogens which are found inside macrophages (mphi) after i. v. infection. it is generally assumed that mphi restrict the replication of the bacteria during infection. in this study we examined the in vivo activities of mphi during experimental s. typhimurium infections, using a selective liposome-based mphi elimination technique. unexpectedly, elimination of mphi prior to infection with virulent s. typhimurium decreased morbidi ...200010741413
survival and filamentation of salmonella enterica serovar enteritidis pt4 and salmonella enterica serovar typhimurium dt104 at low water activity.in this study we investigated the long-term survival of and morphological changes in salmonella strains at low water activity (a(w)). salmonella enterica serovar enteritidis pt4 and salmonella enterica serovar typhimurium dt104 survived at low a(w) for long periods, but minimum humectant concentrations of 8% nacl (a(w), 0. 95), 96% sucrose (a(w), 0.94), and 32% glycerol (a(w), 0.92) were bactericidal under most conditions. salmonella rpos mutants were usually more sensitive to bactericidal level ...200010742199
pathogenic role of sef14, sef17, and sef21 fimbriae in salmonella enterica serovar enteritidis infection of chickens.very little is known about the contribution of surface appendages of salmonella enterica serovar enteritidis to pathogenesis in chickens. this study was designed to clarify the role of sef14, sef17, and sef21 fimbriae in serovar enteritidis pathogenesis. stable, single, defined sefa (sef14), agfa (sef17), and fima (sef21) insertionally inactivated fimbrial gene mutants of serovar enteritidis were constructed. all mutant strains invaded caco-2 and ht-29 enterocytes at levels similar to that of th ...200010742278
salmonella perils of pet reptiles. 200010743310
analysis of plasmid and chromosomal dna of multidrug-resistant salmonella enterica serovar typhi from asia.molecular analysis of chromosomal dna from 193 multidrug-resistant (mdr) salmonella enterica serovar typhi isolates from 1990 to 1995 from pakistan, kuwait, malaysia, bangladesh, and india produced a total of five major different pulsed-field gel electrophoresis (pfge) patterns. even within a particular country mdr s. enterica serovar typhi dna was found to be in different pfge groups. similar self-transferable 98-mda plasmids belonging to either incompatibility group inchi1 or inchi1/fiia were ...200010747124
characterization of salmonella enterica serovar typhimurium dt104 isolated from denmark and comparison with isolates from europe and the united states.a total of 136 isolates of salmonella enterica serovar typhimurium dt104 from denmark (n = 93), germany (n = 10), italy (n = 4), spain (n = 5), and the united kingdom (n = 9) were characterized by antimicrobial resistance analysis, plasmid profiling, pulsed-field gel electrophoresis (pfge) with the restriction enzymes xbai and blni, and analysis for the presence of integrons and antibiotic resistance genes. the isolates from denmark were from nine pig herds, while the isolates from other countri ...200010747147
fluorescent amplified-fragment length polymorphism genotyping of salmonella enterica subsp. enterica serovars and comparison with pulsed-field gel electrophoresis typing.we have performed the fluorescently labeled amplified-fragment length polymorphism (faflp) method on 97 strains of the food-borne pathogen salmonella enterica subsp. enterica comprising seven different serovars using the restriction enzymes ecori and msei. from the total faflp fingerprinted strains, 81 were compared with pulsed-field gel electrophoresis (pfge) typing of the same strains. the faflp method showed a discriminatory power equal to that of pfge. we report a fast, robust, and high-reso ...200010747153
inactivation of the flagellin gene of salmonella enterica serotype enteritidis strongly reduces invasion into differentiated caco-2 cells.a nonflagellated mutant of salmonella enterica serotype enteritidis was constructed by disrupting the flagellin gene (flic). northern blot analysis indicated that the mutation did not affect expression of the downstream fliu gene. infection experiments with differentiated caco-2 cells revealed that the mutant was about 50-fold less invasive than the wild-type strain, while bacterial adherence was unaffected. complementation of the mutant with an intact flic copy restored flagella formation and e ...200010754244
proposal of salmonella paratyphi sp. nov., nom. rev. and request for an opinion to conserve the specific epithet paratyphi in the binary combination salmonella paratyphi as nomen epitheton conservandum.we propose salmonella paratyphi sp. nov., nom. rev., by raising salmonella choleraesuis subsp. choleraesuis serovar paratyphi a to species status and request an opinion to include the specific epithet paratyphi in the binary combination of salmonella paratyphi in the list of epitheta specifica conservanda.200010758909
recognition of nomenclatural standing of salmonella typhi (approved lists 1980), salmonella enteritidis (approved lists 1980) and salmonella typhimurium (approved lists 1980), and conservation of the specific epithets enteritidis and typhimurium. request for an opinion.in 1994, the judicial commission of the icsb announced that le minor and popoff's request for an opinion in 1987 to designate salmonella enterica sp. nov., nom. rev. as the type and only species of the genus salmonella was denied. thus, the current species of the genus salmonella are salmonella typhimurium, salmonella enteritidis, salmonella typhi, salmonella choleraesuis (including six subspecies) and salmonella bongori, with the type species, s. choleraesuis (smith 1894) weldin 1927 (approved ...200010758910
a parallel intraphagosomal survival strategy shared by mycobacterium tuberculosis and salmonella enterica.mycobacterium tuberculosis and salmonella enterica cause very different diseases and are only distantly related. however, growth within macrophages is crucial for virulence in both of these intracellular pathogens. here, we demonstrate that in spite of the phylogenetic distance, m. tuberculosis and salmonella employ a parallel survival strategy for growth within macrophage phagosomes. previous studies established that the salmonella mgtc gene is required for growth within macrophages and for vir ...200010760138
prevalence of subclinical salmonella enterica infection in danish finishing pig herds.our aim was to determine the salmonella enterica prevalence in 96 randomly selected danish pig herds, based on serological examination of blood samples and bacteriological examination of faecal samples (collected simultaneously from the same pens). for comparison, 39 high-seroprevalence herds were included in the study. the representativeness of the selected herds was assessed, based on descriptive statistics of herd size and type. totals of 1330 pen samples and 6814 blood samples were examined. ...200010760401
peptidase e, a peptidase specific for n-terminal aspartic dipeptides, is a serine hydrolase.salmonella enterica serovar typhimurium peptidase e (pepe) is an n-terminal asp-specific dipeptidase. pepe is not inhibited by any of the classical peptidase inhibitors, and its amino acid sequence does not place it in any of the known peptidase structural classes. a comparison of the amino acid sequence of pepe with a number of related sequences has allowed us to define the amino acid residues that are strongly conserved in this family. to ensure the validity of this comparison, we have express ...200010762256
lipopolysaccharide-binding protein and phospholipid transfer protein release lipopolysaccharides from gram-negative bacterial membranes.although animals mobilize their innate defenses against gram-negative bacteria when they sense the lipid a moiety of bacterial lipopolysaccharide (lps), excessive responses to this conserved bacterial molecule can be harmful. of the known ways for decreasing the stimulatory potency of lps in blood, the binding and neutralization of lps by plasma lipoproteins is most prominent. the mechanisms by which host lipoproteins take up the native lps that is found in bacterial membranes are poorly underst ...200010768924
tetanus toxin fragment c expressed in live salmonella vaccines enhances antibody responses to its fusion partner schistosoma haematobium glutathione s-transferase.tetanus toxoid has been used widely as an adjuvant. the atoxic fragment c from tetanus toxin (tetc) is potently immunogenic when expressed in salmonella vaccine strains and has been used as a fusion partner for antigens (ag). however, there has been no formal comparison of the immunomodulatory impact of tetc on its fusion partners. in this study, we have addressed this important issue. the protective 28-kda glutathione s-transferase (gst) from schistosoma haematobium (sh28gst) was expressed eith ...200010768937
the shda gene is restricted to serotypes of salmonella enterica subspecies i and contributes to efficient and prolonged fecal shedding.little is known about factors which enable salmonella serotypes to circulate within populations of livestock and domestic fowl. we have identified a dna region which is present in salmonella serotypes commonly isolated from livestock and domestic fowl (s. enterica subspecies i) but absent from reptile-associated salmonella serotypes (s. bongori and s. enterica subspecies ii to vii). this dna region was cloned from salmonella serotype typhimurium and sequence analysis revealed the presence of a 6 ...200010768965
the flagellar sigma factor flia (sigma(28)) regulates the expression of salmonella genes associated with the centisome 63 type iii secretion system.one of the essential features of all pathogenic strains of salmonella enterica is the ability to enter into nonphagocytic cells. this pathogenic property is mediated by the salmonella pathogenicity island 1 (spi-1)-encoded type iii secretion system. expression of components and substrates of this system is subject to complex regulatory mechanisms. these mechanisms include a number of specific and global transcriptional regulatory proteins. in this study we have compared in s. enterica serovars t ...200010768967
interaction of salmonella enterica serotype typhimurium with dendritic cells is defined by targeting to compartments lacking lysosomal membrane glycoproteins.dendritic cells (dcs) play a central role in the generation of acquired immunity to infections by pathogenic microorganisms. salmonella enterica serotype typhimurium is known to survive and proliferate intracellularly within macrophages and nonphagocytic cells, but no data exist on how this pathogen interacts with dcs. in this report, we show the capacity of serotype typhimurium to survive within the established mouse dc line cb1. in contrast to the case for the macrophage model, the compartment ...200010768999
evidence for active efflux as the primary mechanism of resistance to ciprofloxacin in salmonella enterica serovar typhimurium.the occurrence of active efflux and cell wall modifications were studied in salmonella enterica serovar typhimurium mutants that were selected with enrofloxacin and whose phenotypes of resistance to fluoroquinolones could not be explained only by mutations in the genes coding for gyrase or topoisomerase iv. mutant bn18/21 exhibited a decreased susceptibility to ciprofloxacin (mic = 0.125 microg/ml) but did not have a mutation in the gyra gene. mutants bn18/41 and bn18/71 had the same substitutio ...200010770755
occurrence of a salmonella enterica serovar typhimurium dt104-like antibiotic resistance gene cluster including the flor gene in s. enterica serovar agona.recently a chromosomal locus possibly specific for salmonella enterica serovar typhimurium dt104 has been reported that contains a multiple antibiotic resistance gene cluster. evidence is provided that salmonella enterica serovar agona strains isolated from poultry harbor a similar gene cluster including the newly described flor gene, conferring cross-resistance to chloramphenicol and florfenicol.200010770778
hospital outbreak of salmonella virchow possibly associated with a food handler.a foodborne outbreak of salmonella infection at a private hospital in london in 1994 was found to be associated with eating turkey sandwiches prepared by a food handler. one patient, nine staff, and a foodhandler's baby were confirmed to have salmonella enterica serotype virchow, phage type 26 infection. the attack rate was estimated to be 5% among the approximately 200 patients and staff at risk. a food handler reportedly became ill days after, but her baby days before, the first hospital case. ...200010772833
a small protein that mediates the activation of a two-component system by another two-component system.the pmra-pmrb two-component system of salmonella enterica controls resistance to the peptide antibiotic polymyxin b and to several antimicrobial proteins from human neutrophils. transcription of pmra-activated genes is induced by high iron, but can also be promoted by growth in low magnesium in a process that requires another two-component system, phop-phoq. here, we define the genetic basis for the interaction between the phop-phoq and pmra-pmrb systems. we have identified pmrd as a phop-activa ...200010775270
salmonella typhimurium dt104 from livestock in japan.we examined the distribution of multidrug-resistant salmonella enterica serotype typhimurium definitive phage type 104 (dt104) among japanese livestock from 1973 to 1998. the 144 s. typhimurium field isolates were tested for susceptibility to ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline, kanamycin, trimethoprim, nalidixic acid, and norfloxacin. thirty-six of 68 strains which exhibited resistance to five or more antimicrobials (acssut+) were identified as dt104. resul ...200010777852
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