Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| 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 ... | 2000 | 10762256 |
| 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 ... | 2000 | 10678926 |
| 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 ... | 2000 | 10678973 |
| 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 ... | 2000 | 10768965 |
| 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 ... | 2000 | 10681314 |
| 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 ... | 2000 | 10653725 |
| 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 ... | 2000 | 10655518 |
| 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. | 2000 | 10699039 |
| multidrug-resistant salmonella enterica serotype typhimurium dt104. | 2000 | 10702060 | |
| 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 ... | 2000 | 10702502 |
| 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. | 2000 | 10702512 |
| 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 ... | 2000 | 10613858 |
| prevalence of enteric zoonotic organisms in cats. | to determine prevalence of enteric zoonotic organisms in cats in north-central colorado. | 2000 | 10707683 |
| 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 ... | 2000 | 10712800 |
| 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 ... | 2000 | 10678914 |
| igh-6(-/-) (b-cell-deficient) mice fail to mount solid acquired resistance to oral challenge with virulent salmonella enterica serovar typhimurium and show impaired th1 t-cell responses to salmonella antigens. | in the present study we evaluated the role of b cells in acquired immunity to salmonella infection by using gene-targeted b-cell-deficient innately susceptible mice on a c57bl/6 background (igh-6(-/-)). igh-6(-/-) mice immunized with a live, attenuated aroa salmonella enterica serovar typhimurium vaccine strain showed impaired long-term acquired resistance against the virulent serovar typhimurium strain c5. igh-6(-/-) mice were able to control a primary infection and to clear the inoculum from t ... | 2000 | 10603367 |
| 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 ... | 2000 | 10678970 |
| 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 ... | 2000 | 10653723 |
| in vivo characterization of the murine intranasal model for assessing the immunogenicity of attenuated salmonella enterica serovar typhi strains as live mucosal vaccines and as live vectors. | attenuated salmonella enterica serovar typhi live vector vaccine strains are highly immunogenic in mice following intranasal but not orogastric inoculation. to elucidate the relationship between organs within which vaccine organisms are found and the induction of specific serum immunoglobulin g (igg) antibodies, we examined the in vivo distribution of serovar typhi vaccine strain cvd 908-htra following intranasal administration. vaccine organisms were cultured from the nasal lymphoid tissue (nal ... | 2000 | 10603389 |
| 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 ... | 2000 | 10685108 |
| 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 ... | 2000 | 10692360 |
| 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 ... | 2000 | 10692365 |
| 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 ... | 2000 | 10677853 |
| 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. | 2000 | 10656352 |
| 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 ... | 2000 | 10648538 |
| 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 ... | 2000 | 10655411 |
| 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 ... | 2000 | 10648508 |
| 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 ... | 2000 | 10629197 |
| 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 ... | 2000 | 10629201 |
| 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. | 2000 | 10629202 |
| 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 ... | 2000 | 10613867 |
| 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 ... | 2000 | 10613887 |
| 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 ... | 2000 | 10613889 |
| 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 ... | 2000 | 10618104 |
| a novel integron in salmonella enterica serovar enteritidis, carrying the bla(dha-1) gene and its regulator gene ampr, originated from morganella morganii. | the genetic organization of the gene coding for dha-1 and the corresponding ampr gene was determined by pcr mapping. these genes have been mobilized from the morganella morganii chromosome and inserted into a complex suli-type integron, similar to in6 and in7. however, they are not themselves mobile cassettes. this integron probably includes a specific site for recombination allowing the mobilization of diverse resistance genes, as observed for bla(cmy-1) and bla(mox-1). | 2000 | 10602756 |
| evaluation of the effect of mannan-oligosaccharides on the competitive exclusion of salmonella enteritidis colonization in broiler chicks. | this study evaluated the protection against colonization by salmonella enterica serovar enteritidis in the chick's caecum when dosed with caecal contents from hens fed dietary carbohydrates based on mannose. protection was investigated by comparing the effects of four suspensions of hen caecal contents (hcc) fed diets supplemented with 2.5% d -mannose (man-hcc), 2.5% mannoseoligosaccharide (mos-hcc), 2.5% palm kernel meal (pkm-hcc) or unsupplemented mash (mashhcc). four trials to quantify and co ... | 2000 | 19184854 |
| protection against experimental fowl typhoid by parenteral administration of live sl5828, an aroa-serc (aromatic dependent) mutant of a wild-type salmonella gallinarum strain made lysogenic for p22 sie. | a wild-type strain of salmonella enterica serotype gallinarum, lysogenized with p22 sie (superinfection-exclusion defective) was greatly attenuated for newly hatched or 21-day-old chickens. an aroa transductant of the lysogenic strain and an aroa-serc tetracycline-sensitive deletion or deletioninversion mutant of the latter were equally attenuated. intramuscular administration of the aroa-serc strain to 21-day-old chickens protected them against oral challenge with 10(6) colony forming units of ... | 2000 | 19184834 |
| pathogenicity of salmonella enteritidis phage types 4, 8 and 23 in specific pathogen free chicks. | the pathogenicity of two isolates of salmonella enterica serovar enteritidis (se) phage type (pt) 4, three of pt8 and one of pt23 was investigated in groups of 1-day-old specific pathogen free white leghorn chicks. two groups were crop gavaged with each culture but at two different doses. two additional groups were given salmonella enterica serovar pullorum (sp) at similar doses and one further group served as uninoculated controls. body weights were recorded at 14, 21, and 28 days postinoculati ... | 2000 | 19184855 |
| salmonella derby cross-protection study. | an avirulent live (avl), salmonella choleraesuis vaccine (salmo shield live [grand laboratories, inc.]) was administered to pigs at weaning or 3 weeks of age. two weeks after vaccination the vaccinated pigs as well as unvaccinated control pigs were challenged intranasally with a commonly isolated environmental salmonella serotype, s. derby. at 2, 4, and 6 weeks after challenge, pigs were euthanized and cultured for s. derby. although the number of pigs in this study was too small to draw any def ... | 2000 | 19757566 |
| experimental salmonella enterica serovar pullorum infection in two commercial varieties of laying hens. | an experiment was carried out to investigate the biology of salmonella pullorum in two varieties of laying hens, from 5 days of age up to 9 months. one variety was resistant to systemic salmonellosis (light layers producing white eggs) and the other was considered susceptible (brown layers producing brown eggs). the brown birds were more affected by the infection, showing signs of clinical disease in the first month of life. later, these signs disappeared, but postmortem examination revealed per ... | 2001 | 19184886 |
| observations on the persistence and vertical transmission of salmonella enterica serovars pullorum and gallinarum in chickens: effect of bacterial and host genetic background. | commercial laying hens inoculated with a strain of salmonella enterica ser. pullorum when they were 4 days old showed no morbidity, but harboured infection until they came into lay, and then produced s. pullorum-contaminated eggs and infected progeny. there was limited evidence of transmission of maternal immunity to the progeny. attempts were made to set up similar infections in hens with salmonella gallinarum, but without success. infection either resulted in clinical disease or elimination of ... | 2001 | 19184904 |
| further studies on vertical transmission and persistence of salmonella enterica serovar enteritidis phage type 4 in chickens. | one-week-old commercial layers were infected orally with 10(8) colony forming units of salmonella enterica serovar enteritidis phage type 4. no mortality was observed. the inoculated organism was isolated in decreasing viable numbers from a number of tissues, particularly the spleen, liver and caeca. organisms present in the spleen were primarily localized within macrophages. no salmonella enteritidis organisms were isolated between 10 and 24 weeks of age, when the experiment was terminated afte ... | 2001 | 19184915 |
| mural endocarditis caused by salmonella virchow: survival with conservative treatment. | we describe a case of endocarditis caused by salmonella enterica serotype virchow, which was treated conservatively with antibiotics alone. it is the only reported case of survival from salmonella endocarditis with conservative treatment, and the first reported case of endocarditis caused by salmonella virchow. the changing prevalence, virulence patterns and importance of salmonella species in endocarditis are discussed. | 2001 | 16352056 |
| [infective etiology of diarrhea in adults with hiv infection in dakar: a case-control study on 594 patients]. | a survey was conducted in dakar, senegal from may 1997 to may 1999, to identify major types and prevalences of bacteria, parasites, fungi and rotaviruses associated with diarrhea in relation to human immunodeficiency virus serostatus with the aim to provide guidance to physicians for case management. etiologic agents were identified in a case-control study: cases were hiv-infected patients with diarrhea (hiv+ d+) and hiv seronegative patients with diarrhea (hiv- d+); controls were hiv-infected p ... | 2001 | 15773157 |
| alternative pathways for siroheme synthesis in klebsiella aerogenes. | siroheme, the cofactor for sulfite and nitrite reductases, is formed by methylation, oxidation, and iron insertion into the tetrapyrrole uroporphyrinogen iii (uro-iii). the cysg protein performs all three steps of siroheme biosynthesis in the enteric bacteria escherichia coli and salmonella enterica. in either taxon, cysg mutants cannot reduce sulfite to sulfide and require a source of sulfide or cysteine for growth. in addition, cysg-mediated methylation of uro-iii is required for de novo synth ... | 2001 | 11114933 |
| methionine-to-cysteine recycling in klebsiella aerogenes. | in the enteric bacteria escherichia coli and salmonella enterica, sulfate is reduced to sulfide and assimilated into the amino acid cysteine; in turn, cysteine provides the sulfur atom for other sulfur-bearing molecules in the cell, including methionine. these organisms cannot use methionine as a sole source of sulfur. here we report that this constraint is not shared by many other enteric bacteria, which can use either cysteine or methionine as the sole source of sulfur. the enteric bacterium k ... | 2001 | 11114934 |
| aromatic compound-dependent brucella suis is attenuated in both cultured cells and mouse models. | the aroc gene of the facultative intracellular pathogen brucella suis was cloned and sequenced. the cloned aroc gene complements escherichia coli and salmonella enterica serovar typhimurium aroc mutants. a b. suis aroc mutant was found to be unable to grow in a defined medium without aromatic compounds. the mutant was highly attenuated in tissue culture (thp1 macrophages and hela cells) and murine virulence models. | 2001 | 11119550 |
| immunity against helicobacter pylori: significance of interleukin-4 receptor alpha chain status and gender of infected mice. | vaccination of interleukin-4 (il-4) receptor alpha (il-4ralpha) chain-deficient balb/c mice with helicobacter pylori urease and cholera toxin or with urease-expressing, live attenuated salmonella enterica serovar typhimurium cells revealed that protection against h. pylori infection is independent of il-4- or il-13-mediated signals. a comparison of male and female mice suggests a sexual dimorphism in the extent of bacterial colonization that is particularly evident in the absence of the il-4ralp ... | 2001 | 11119552 |
| analysis of expression of flagella by salmonella enterica serotype typhimurium by monoclonal antibodies recognising both phase specific and common epitopes. | monoclonal antibodies specific for phase 1 ("i" antigen), phase 2 ("1,2" antigen) and common epitopes of the flagellins of salmonella enterica serotype typhimurium were raised. having confirmed their specificity, the monoclonal antibodies were used to develop semi-quantitative elisas in order to assess the relative expression of the two phases by strains of typhimurium. the majority of typhimurium strains representative of a wide cross-section of definitive types from animal and environmental so ... | 2001 | 11118742 |
| purification and characterization of waap from escherichia coli, a lipopolysaccharide kinase essential for outer membrane stability. | in escherichia coli, salmonella enterica, and pseudomonas aeruginosa, the waap (rfap) gene product is required for the addition of phosphate to o-4 of the first heptose residue of the lipopolysaccharide (lps) inner core region. this phosphate substitution is particularly important to the biology of these bacteria; it has previously been shown that waap is necessary for resistance to hydrophobic and polycationic antimicrobials in e. coli and that it is required for virulence in invasive strains o ... | 2001 | 11069912 |
| bacteriophage-bacteriophage interactions in the evolution of pathogenic bacteria. | many bacteriophages carry virulence genes encoding proteins that play a major role in bacterial pathogenesis. recently, investigators have identified bacteriophage-bacteriophage interactions in the bacterial host cell that also contribute significantly to the virulence of bacterial pathogens. the relationships between the bacteriophages pertain to one bacteriophage providing a helper function for another, unrelated bacteriophage in the host cell. accordingly, these interactions can involve the m ... | 2001 | 11303502 |
| thermal inactivation of stationary-phase and acid-adapted escherichia coli o157:h7, salmonella, and listeria monocytogenes in fruit juices. | the heat resistance of stationary-phase and acid-adapted escherichia coli o157:h7, salmonella enterica (serotypes typhimurium, enteritidis, gaminara, rubislaw, and hartford), and listeria monocytogenes was evaluated in single-strength apple. orange, and white grape juices adjusted to ph 3.9. the heat resistance increased significantly (p < 0.05) after acid adaptation. salmonella had an overall lower heat resistance than the other pathogens. acid-adapted e. coli o157:h7 presented the highest heat ... | 2001 | 11252473 |
| induction of protective immunity against streptococcus mutans colonization after mucosal immunization with attenuated salmonella enterica serovar typhimurium expressing an s. mutans adhesin under the control of in vivo-inducible nirb promoter. | the purpose of the present study was to evaluate the effectiveness of an attenuated salmonella enterica serovar typhimurium vaccine strain expressing the saliva-binding region (sbr) of the streptococcus mutans antigen i/ii adhesin, either alone or linked with the mucosal adjuvant cholera toxin a2 and b subunits (cta2/b) and under the control of the anaerobically inducible nirb promoter, in inducing a protective immune response against s. mutans infection. balb/c mice were immunized by either the ... | 2001 | 11254570 |
| a synaptojanin-homologous region of salmonella typhimurium sigd is essential for inositol phosphatase activity and akt activation. | the ser-thr kinase akt is activated in epithelial cells by salmonella enterica serovar typhimurium. the bacterial effector sigd, which is translocated into host cells via the specialized type iii secretion system, is essential for akt activation. here, we investigated the inositol phospholipid substrate preferences of sigd. recombinant sigd preferentially dephosphorylated phosphatidylinositol 3,5-biphosphate and phosphatidylinositol 3,4,5-triphosphate over other phosphatidylinositol lipids. phos ... | 2001 | 11311241 |
| curli fibers mediate internalization of escherichia coli by eukaryotic cells. | curli fibers are adhesive surface fibers expressed by escherichia coli and salmonella enterica that bind several host extracellular matrix and contact phase proteins and were assumed to have a role in pathogenesis. the results presented here suggest that one such role is internalization into host cells. an e. coli k-12 strain transformed with a low-copy vector containing the gene cluster encoding curli fibers (csg operon) was internalized by several lines of eukaryotic cells. the internalization ... | 2001 | 11254632 |
| restricted growth of ent(-) and tonb mutants of salmonella enterica serovar typhi in human mono mac 6 monocytic cells. | monocytes and macrophages are an important host defense in humans infected with salmonella enterica serovar typhi. bacterial ability to survive in these cells is therefore a crucial virulence characteristic of this pathogen. in this study, we demonstrate that growth of a salmonella enterica serovar typhi enterochelin synthesis mutant and a tonb mutant in the human monocyte cell line mono mac 6 is restricted compared to that of the parental wild-type ty2 strain. these results suggest that enteroc ... | 2001 | 11257540 |
| identification of a non-haem catalase in salmonella and its regulation by rpos (sigmas). | we report the identification and functional analysis of katn, a gene encoding a non-haem catalase of salmonella enterica serotype typhimurium. katn, which is not present in escherichia coli, is located between the ycigfe and ycid e. coli homologues in the salmonella genome. its predicted protein product has a molecular weight of 31 826 da and is similar to the mn-catalases of lactobacillus plantarum and thermus spp. its product, katn, was visualized as a 37 kda protein in e. coli maxicells. a ka ... | 2001 | 11260470 |
| evolutionary adaptation to temperature. viii. effects of temperature on growth rate in natural isolates of escherichia coli and salmonella enterica from different thermal environments. | are enteric bacteria specifically adapted to the thermal environment of their hosts? in particular, do the optimal temperatures and thermal niches of the bacterial flora reflect seasonal, geographic, or phylogenetic differences in their hosts' temperatures? we examined these questions by measuring the relationship between the temperature-dependent growth rates of enteric bacteria in a free-living ectothermic host. we sampled two species of enteric bacteria (escherichia coli and salmonella enteri ... | 2001 | 11263744 |
| seroprevalence and antibiotic sensitivity of serotypes of salmonella enterica in greek pig herds. | blood samples were taken from 50 pigs in each of 59 farrow-to-finish production herds and from 40 pigs in each of four of five registered multiplying herds. samples of feed and faeces were also collected from 17 of the production herds and from the four multiplying herds. the sera were tested for antibodies to salmonella enterica by the danish mix-elisa, and the organisms were isolated, serotyped and sensitivity tested by standard techniques. the average within-herd seroprevalence was 3.4 per ce ... | 2001 | 11327648 |
| low-molecular-weight plasmid of salmonella enterica serovar enteritidis codes for retron reverse transcriptase and influences phage resistance. | retron reverse transcriptases are unusual procaryotic enzymes capable of synthesis of low-molecular-weight dna by reverse transcription. all of the so-far-described dna species synthesized by retron reverse transcriptases have been identified as multicopy single-stranded dna. we have shown that salmonella enterica serovar enteritidis is also capable of synthesis of the low-molecular-weight dna by retron reverse transcriptase. surprisingly, salmonella serovar enteritidis-produced low-molecular-we ... | 2001 | 11292805 |
| enhancement of translation by the epsilon element is independent of the sequence of the 460 region of 16s rrna. | the epsilon enhancer element is a pyrimidine-rich sequence that increases expression of t7 gene 10 and a number of escherichia coli mrnas during initiation of translation and inhibits expression of the recf mrna during elongation. based on its complementarity to the 460 region of 16s rrna, it has been proposed that epsilon exerts its enhancer activity by base pairing to this complementary rrna sequence. we have tested this model of enhancer action by constructing mutations in the 460 region of 1 ... | 2001 | 11266541 |
| flagellin expressed by live salmonella vaccine strains induces distinct antibody responses following delivery via systemic or mucosal immunization routes. | salmonella flagellin, expressed as flagella in live attenuated vaccine strains, elicits distinct systemic (igg) and secreted (iga) antibody responses in mice following delivery via mucosal (nasal/oral) or parenteral (intraperitoneal (i.p.)) immunization routes. reduced flagellin-specific antibodies were detected either systemically or locally following delivery of flagellated derivatives of aroa salmonella enterica serovar dublin sl1438 via the nasal route, the most effective mucosal site for ac ... | 2001 | 11335139 |
| virulent strains of salmonella enteritidis disrupt the epithelial barrier of caco-2 and hep-2 cells. | to confirm the existence in nature of salmonella enteritidis strains of different degrees of virulence and to elucidate the mechanisms underlying the effects of such strains on the epithelial barrier function, the consequences of infection of caco-2 cells and hep-2 cells with 15 s. enteritidis strains in a chicken infection model were examined. the more virulent strains of s. enteritidis, which are biofilm producers in adherence test medium, were able to disrupt hep-2 and caco-2 monolayers, as s ... | 2001 | 11271420 |
| safety and immunogenicity of live recombinant salmonella enterica serovar typhi ty21a expressing urease a and b from helicobacter pylori in human volunteers. | helicobacter pylori urease was expressed in the common live typhoid vaccine ty21a yielding ty21a(pdb1). nine volunteers received ty21a(pdb1) and three control volunteers received ty21a. no serious adverse effects were observed in any of the volunteers. ten out of 12 volunteers developed humoral immune responses to the salmonella carrier as detected by antigen-specific antibody-secreting cells but only two volunteers seroconverted. a total of five volunteers showed responses in one or two out of ... | 2001 | 11738748 |
| epitope tagging of chromosomal genes in salmonella. | we have developed a simple and efficient procedure for adding an epitope-encoding tail to one or more genes of interest in the bacterial chromosome. the procedure is a modification of the gene replacement method of datsenko and wanner [datsenko, k. a. & wanner, b. l. (2000) proc. natl. acad. sci. usa 97, 6640-6645]. a dna module that begins with the epitope-encoding sequence and includes a selectable marker is amplified by pcr with primers that carry extensions (as short as 36 nt) homologous to ... | 2001 | 11742086 |
| naturally occurring anti-salmonella agents. | polygodial and (2e)-hexenal were found to possess antibacterial activity against salmonella choleraesuis with the minimum bactericidal concentrations (mbc) of 50 microg/ml (0.17 mm) and 100 microg/ml (0.98 mm), respectively. the time kill curve study showed that these two alpha,beta-unsaturated aldehydes were bactericidal against this food-borne bacterium at any stage of growth. however, they showed different effects on the growth of s. choleraesuis. the combination of polygodial and anethole ex ... | 2001 | 11743758 |
| reduced fluoroquinolone susceptibility in salmonella enterica serotypes in travelers returning from southeast asia. | during 1995 to 1999, we collected 1,210 salmonella isolates; 629 were from finnish travelers returning from abroad. these isolates were tested for susceptibility by determining mics to ciprofloxacin, nalidixic acid, and seven additional antimicrobial agents. from 1995 to 1999, the annual proportion of reduced ciprofloxacin susceptibility (mic > 0.125 microg/ml) among all travelers' isolates increased from 3.9% to 23.5% (p<0.001). the increasing trend was outstanding among the isolates from south ... | 2001 | 11747728 |
| a multistate outbreak of salmonella enterica serotype baildon associated with domestic raw tomatoes. | salmonella enterica serotype baildon, a rare serotype, was recovered from 86 persons in eight states; 87% of illnesses began during a 3-week period ending january 9, 1999. raw restaurant-prepared tomatoes were implicated in multiple case-control studies. contamination likely occurred on the farm or during packing; more effective disinfection and prevention strategies are needed. | 2001 | 11747740 |
| efficacy of chitosan, carvacrol, and a hydrogen peroxide-based biocide against foodborne microorganisms in suspension and adhered to stainless steel. | the ability of natural compounds to inactivate foodborne organisms adhered to surfaces was investigated with the ultimate aim of replacing synthetic biocides by more environmentally friendly, natural alternatives. the antimicrobial efficacy of 0.5, 1.0, and 2.0% chitosan and spor-klenz rtu (a commercial biocide based on hydrogen peroxide and peroxyacetic acid) and 0.5, 1.25, and 2.0 mm carvacrol was determined at 20 degrees c against listeria monocytogenes, salmonella enterica serovar typhimuriu ... | 2001 | 11601703 |
| [multidrug-resistant and fluoroquinolone-resistant salmonella enterica serotype typhimurium definitive phage type 12 isolated from infantile diarrhea]. | a 35-day-old male infant was admitted to our hospital, presenting a high fever, vomiting, and diarrhea. multidrug-resistant and fluoroquinolon-resistant salmonella serotype typhimurium was isolated from his stool. the phage type of the strain was dt12. the strain was resistant to ampicillin, streptomycin, gentamicin, tetracycline, chloramphenicol, sulfamethoxazole-trimethoprim, and fluoroquinolones (levofloxacin; mic 8 micrograms/ml, norfloxacin; 24 micrograms/ml, ciprofloxacin; 16 micrograms/ml ... | 2001 | 11605192 |
| the isolation of antibiotic-resistant salmonella from retail ground meats. | salmonella is a leading cause of foodborne illness. the emergence of antimicrobial-resistant salmonella is associated with the use of antibiotics in animals raised for food; resistant bacteria can be transmitted to humans through foods, particularly those of animal origin. we identified and characterized strains of salmonella isolated from ground meats purchased in the washington, d.c., area. | 2001 | 11642230 |
| [five cases of gastroenteritis with multiresistant salmonella enterica serovar typhimurium dt104 related to farm animals in denmark]. | whereas the overall incidence of human salmonella infections in denmark has fallen during the past three years, the number of infections with multidrug-resistant salmonella typhimurium definitive type 104 (dt104) has risen. we report five cases of human infection with dt104 in patients living on farms, in which cattle and mixed herds of cattle and pigs were infected with dt104. transmission from the animals to the patients in the cases described is likely to have occurred. these cases emphasize ... | 2001 | 11665472 |
| [outbreak of salmonella bovismorbificans infection]. | 2001 | 11665476 | |
| hha is a negative modulator of transcription of hila, the salmonella enterica serovar typhimurium invasion gene transcriptional activator. | an early step in the establishment of salmonella enterica serovar typhimurium murine infection is the penetration of the intestinal mucosa of the small intestine. the majority of the genes responsible for the salmonella invasive phenotype are encoded on salmonella pathogenicity island 1, and their transcription is controlled by the hila transcriptional activator. the expression of hila is regulated by environmental signals including oxygen, osmolarity, ph, and growth phase such that the presence ... | 2001 | 11673432 |
| detection of decreased in vitro susceptibility to ciprofloxacin in salmonella enterica serotypes typhi and paratyphi a. | 2001 | 11679569 | |
| the rfah gene, which affects lipopolysaccharide synthesis in salmonella enterica serovar typhi, is differentially expressed during the bacterial growth phase. | we have cloned and sequenced the rfah gene from salmonella enterica serovar typhi strain ty2. the gene showed a high degree of similarity to the rfah genes from escherichia coli k-12 and s. enterica serovar typhimurium. a rfah mutant was constructed by site-directed mutagenesis. this mutant produced a rough lipopolysaccharide (lps), with an incomplete core region. the defect in lps expression that results from the rfah mutation was corrected by a plasmid carrying the intact gene. the plasmid-bor ... | 2001 | 11682190 |
| characterization of salmonella associated with pig ear dog treats in canada. | in the summer of 1999, the incidence of salmonella enterica serotype infantis infections in alberta rose dramatically. subsequent laboratory and epidemiological investigations established that an outbreak of human disease caused by this organism was occurring across canada and was associated with pet treats for dogs produced from processed pig ears. laboratory investigations using phage typing and pulsed-field gel electrophoresis (pfge) established that isolates of salmonella serotype infantis f ... | 2001 | 11682515 |
| structural and biochemical characterization of the type iii secretion chaperones cest and sige. | several gram-negative bacterial pathogens have evolved a type iii secretion system to deliver virulence effector proteins directly into eukaryotic cells, a process essential for disease. this specialized secretion process requires customized chaperones specific for particular effector proteins. the crystal structures of the enterohemorrhagic escherichia coli o157:h7 tir-specific chaperone cest and the salmonella enterica sigd-specific chaperone sige reveal a common overall fold and formation of ... | 2001 | 11685226 |
| salmonella interactions with host cells: type iii secretion at work. | the bacterial pathogen salmonella enterica has evolved a very sophisticated functional interface with its vertebrate hosts. at the center of this interface is a specialized organelle, the type iii secretion system, that directs the translocation of bacterial proteins into the host cell. salmonella spp. encode two such systems that deliver a remarkable array of bacterial proteins capable of modulating a variety of cellular functions, including actin cytoskeleton dynamics, nuclear responses, and e ... | 2001 | 11687484 |
| epithelial cell contact-induced alterations in salmonella enterica serovar typhi lipopolysaccharide are critical for bacterial internalization. | the invasion of pseudomonas aeruginosa and salmonella enterica serovar typhi into epithelial cells depends on the cystic fibrosis transmembrane conductance regulator (cftr) protein as an epithelial receptor. in the case of p. aeruginosa, the bacterial ligand for cftr is the outer core oligosaccharide portion of the lipopolysaccharide (lps). to determine whether serovar typhi lps is also a bacterial ligand mediating internalization, we used both p. aeruginosa and serovar typhi lps as a competitiv ... | 2001 | 11696036 |
| a minor capsid protein p30 is essential for bacteriophage prd1 capsid assembly. | bacteriophage prd1 is a double-stranded dna virus infecting gram-negative hosts. it has a membrane component located in the interior of the isometric capsid. in addition to the major capsid protein p3, the capsid contains a 9 kda protein p30. protein p30 is proposed to be located between the adjacent facets of the icosahedral capsid and is required for stable capsid assembly. in its absence, an empty phage-specific membrane vesicle is formed. the major protein component of this vesicle is a phag ... | 2001 | 11697904 |
| papb paralogues and their effect on the phase variation of type 1 fimbriae in escherichia coli. | recent work has demonstrated that expression of type 1 fimbriae is repressed by papb, a regulator of pyelonephritis-associated pili (p-pili). papb belongs to family of related adhesin regulators, for which consensus residues required for dna binding and oligomerization have been identified. of the regulators tested in this study, papb, sfab (s-fimbriae) and pefb (salmonella enterica serovar typhimurium--plasmid-encoded fimbriae) repressed fimb-promoted off-to-on inversion of the fim switch, alth ... | 2001 | 11703657 |
| novel salmonella enterica serovar typhimurium protein that is indispensable for virulence and intracellular replication. | upon contact with host cells, the intracellular pathogen salmonella enterica serovar typhimurium promotes its uptake, targeting, and survival in intracellular niches. in this process, the bacterium evades the microbicidal effector mechanisms of the macrophage, including oxygen intermediates. this study reports the phenotypic and genotypic characterization of an s. enterica serovar typhimurium mutant that is hypersusceptible to superoxide. the susceptible phenotype is due to a mudj insertion-inac ... | 2001 | 11705915 |
| salmonella enterica serovar pullorum persists in splenic macrophages and in the reproductive tract during persistent, disease-free carriage in chickens. | salmonella enterica serovar pullorum is worldwide a poultry pathogen of considerable economic importance, particularly in those countries with a developing poultry industry. in addition to the characteristic high mortality rates among young chicks, one of the features of salmonella serovar pullorum infection is that it persists for long periods in convalescent chicks in the absence of clinical disease. this can lead to colonization of the reproductive tract of chickens and at sexual maturity can ... | 2001 | 11705970 |
| survival and distribution of cell-free sef 21 of salmonella enterica serovar enteritidis in the stomach and various compartments of the rat gastrointestinal tract in vivo. | rats were dosed for 6 days with purified sef 21 fimbriae of salmonella enterica serovar enteritidis 10360. the levels of fimbriae in gut contents associated with tissues and in the faeces were quantified by direct non-competitive elisa. sef 21 was distributed throughout the gut. the majority was found in the large intestine where it was primarily in the luminal contents. in contrast, a high proportion of sef 21 detected in the ileum, the main site of salmonella colonisation and invasion, was tis ... | 2001 | 11761188 |
| increase in salmonella enterica subspecies diarizonae serovar 61:k:1,5,(7) in sheep. | 2001 | 11720209 | |
| monitoring of chicken houses and an attached egg-processing facility in a laying farm for salmonella contamination between 1994 and 1998. | two chicken houses and an attached egg-processing facility in a laying farm were sampled between 1994 and 1998 to investigate salmonella contamination. each of the houses was environmentally controlled and fitted with egg belts that transported eggs from the houses to the egg-processing facility. four hundred twenty-eight salmonella isolates were obtained from 904 environmental samples collected from the houses. two hundred fifty-two of the 428 (58.9%) isolates yielded five serotypes as follows: ... | 2001 | 11770616 |
| cellular location and temperature-dependent assembly of inchi1 plasmid r27-encoded trhc-associated conjugative transfer protein complexes. | conjugal transfer of inchi plasmid dna between gram-negative bacteria is temperature sensitive, as mating is optimal between 22 degrees c and 30 degrees c but is inhibited at 37 degrees c. r27, isolated from salmonella enterica serovar typhi, is an inchi1 plasmid of 180 kbp that has been sequenced completely. the gene encoding green fluorescent protein (gfp) was inserted into r27 in frame with trhc. trhc is a mating pair formation (mpf) protein that is essential for plasmid transfer and h-pilus ... | 2001 | 11722736 |
| evaluation of universal preenrichment broth for growth of heat-injured pathogens. | universal preenrichment broth (upb) was developed to enable enrichment of injured foodborne pathogens of different genera simultaneously in lieu of having to undergo separate simultaneous enrichment cultures for subsequent detection or isolation of each pathogen. enrichment conditions in upb for growth of injured pathogens to populations that will enable pathogen detection by rapid immuno-based or polymerase chain reaction (pcr)-based assays have not been defined. hence, studies were done to det ... | 2001 | 11726154 |
| prevalence of salmonella serovars in chickens in turkey. | in this study, 151 (18.6%) of 814 ceca obtained during in-line processing of 28 broiler (hybro g, avian, arbor acres, and cobb breeds) and 5 layer (ross, tetra sl, isa brown, and brown nick breeds) flocks in turkey were found to be contaminated with four different salmonella serovars. only salmonella enterica subsp. enterica serovar enteritidis (salmonella enteritidis) was recovered from layer birds, whereas salmonella enteritidis (81.5%). salmonella agona (7.6%), salmonella thompson (10.1%), an ... | 2001 | 11726169 |
| three molecular methods to identify salmonella enterica serotype typhimurium dt104: pcr fingerprinting, multiplex pcr and rapid pfge. | here we report the accuracy with which three molecular techniques (pcr fingerprinting, multiplex pcr and macrorestriction profiling) distinguished salmonella enterica typhimurium dt104 (hereafter referred to as dt104) from other related strains of salmonella. each technique was tested by screening a set of 20 isolates (10 dt104, eight non-dt104 typhimurium, one s. enterica agona, one s. enterica newport) and each consistently differentiated dt104 from non-dt104 isolates based on visual inspectio ... | 2001 | 11728711 |
| contribution of flagella and invasion proteins to pathogenesis of salmonella enterica serovar enteritidis in chicks. | to explore the relative contribution that flagella and salmonella invasion proteins make to the virulence of salmonella enteritidis in poultry, 20-day-old chicks were challenged orally and by subcutaneous injection with wild-type strain se-hcd, two non-flagellated mutants (flic::tn10 mutant and flhd::tn10 mutant) and two salmonella invasion protein insertion mutants (sipd and iacp). when injected subcutaneously, wild-type se-hcd was the only strain to cause substantial mortality and morbidity an ... | 2001 | 11731137 |
| sira orthologs affect both motility and virulence. | the sira gene of salmonella enterica serovar typhimurium encodes a two-component response regulator of the fixj family that has a positive regulatory influence on the expression of type iii secretion genes involved with epithelial cell invasion and the elicitation of bovine gastroenteritis. sira orthologs in pseudomonas, vibrio, and erwinia control the expression of distinct virulence genes in these genera, but an evolutionarily conserved target of sira regulation has never been identified. in t ... | 2001 | 11244064 |
| antibodies against listerial protein 60 act as an opsonin for phagocytosis of listeria monocytogenes by human dendritic cells. | human-monocyte-derived dendritic cells (modc) are very efficient in the uptake of listeria monocytogenes, a gram-positive bacterium which is an important pathogen in humans and animals causing systemic infections with symptoms such as septicemia and meningitis. in this work, we analyzed the influence of blood plasma on the internalization of l. monocytogenes into human modc and compared the uptake of l. monocytogenes with that of salmonella enterica serovar typhimurium and yersinia enterocolitic ... | 2001 | 11292729 |
| stable transfection of the bovine nramp1 gene into murine raw264.7 cells: effect on brucella abortus survival. | genetically based natural resistance to brucellosis in cattle provides for novel strategies to control zoonotic diseases. bovine nramp1, the homologue of a murine gene (bcg), has been identified as a major candidate for controlling the in vivo resistant phenotype. we developed an in vitro model for expression of resistance- and susceptibility-associated alleles of bovine nramp1 as stable transgenes under the regulatory control of the bovine nramp1 promoter in the murine raw264.7 macrophage cell ... | 2001 | 11292730 |
| antibiotic susceptibilities of salmonella enterica serovar typhi and s. enterica serovar paratyphi a isolated from patients in japan. | the antibiotic susceptibilities of 62 strains of salmonella enterica serovar typhi and 37 strains of s. enterica serovar paratyphi a were investigated with 18 antibiotics. eighteen s. enterica serovar typhi isolates and five s. enterica serovar paratyphi a isolates were resistant to one or more antimicrobial agents, among which 10 s. enterica serovar typhi isolates were nalidixic acid resistant and also showed decreased ciprofloxacin susceptibility. | 2001 | 11181390 |
| roles of hilc and hild in regulation of hila expression in salmonella enterica serovar typhimurium. | sequences between -332 and -39 upstream of the hila promoter are required for repression of hila. an unidentified repressor is thought to bind these upstream repressing sequences (urs) to inhibit hila expression. two arac-like transcriptional regulators encoded on salmonella pathogenicity island 1 (spi1), hilc and hild, bind to the urs to counteract the repression of hila. the urs is required for regulation of hila by osmolarity, oxygen, phop/phoq, and sira/bara. here, we show that fadd, fliz, p ... | 2001 | 11292791 |
| evaluation of the components of a commercial probiotic in gnotobiotic mice experimentally challenged with salmonella enterica subsp. enterica ser. typhimurium. | vitacanis((r)), a probiotic preparation containing a lactobacillus acidophilus, an enterococcus faecium and a saccharomyces cerevisiae, has been developed for the prevention of intestinal disorders in dogs and cats. in the present study, these microorganisms were tested jointly or singly during experimental infection of gnotobiotic mice with salmonella typhimurium. four experimental groups consisting of animals given probiotics jointly or singly and a control group consisting of germfree mice we ... | 2001 | 11230939 |
| bap, a staphylococcus aureus surface protein involved in biofilm formation. | identification of new genes involved in biofilm formation is needed to understand the molecular basis of strain variation and the pathogenic mechanisms implicated in chronic staphylococcal infections. a biofilm-producing staphylococcus aureus isolate was used to generate biofilm-negative transposon (tn917) insertion mutants. two mutants were found with a significant decrease in attachment to inert surfaces (early adherence), intercellular adhesion, and biofilm formation. the transposon was inser ... | 2001 | 11292810 |
| disruption of the genes for clpxp protease in salmonella enterica serovar typhimurium results in persistent infection in mice, and development of persistence requires endogenous gamma interferon and tumor necrosis factor alpha. | the enteric pathogen salmonella enterica serovar typhimurium, similar to other facultative intracellular pathogens, has been shown to respond to the hostile conditions inside macrophages of the host organism by producing a set of stress proteins that are also induced by various environmental stresses. the stress-induced clpxp protease is a member of the atp-dependent proteases, which are known to be responsible for more than 90% of all proteolysis in escherichia coli. to investigate the contribu ... | 2001 | 11292737 |