Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| modulation of phosphoinositide metabolism by pathogenic bacteria. | phosphoinositide metabolism plays a pivotal role in the regulation of receptor-mediated signal transduction, actin remodelling and membrane dynamics. phosphoinositides co-ordinate these processes by recruiting protein effectors to distinct cellular membranes in a time- and organelle-dependent manner. intracellular bacterial pathogens interfere with phosphoinositide metabolism to direct their entry into eukaryotic cells, form replication-permissive vacuoles, modulate apoptosis, or trigger fluid s ... | 2006 | 16939534 |
| complete nucleotide sequence of pk245, a 98-kilobase plasmid conferring quinolone resistance and extended-spectrum-beta-lactamase activity in a clinical klebsiella pneumoniae isolate. | a plasmid containing the qnrs quinolone resistance determinant and the gene encoding the shv-2 beta-lactamase has been discovered from a clinical klebsiella pneumoniae strain isolated in taiwan. the complete 98-kb sequence of this plasmid, designated pk245, was determined by using a whole-genome shotgun approach. transfer of pk245 conferred low-level resistance to fluoroquinolones in electroporant escherichia coli epi300. the sequence of the immediate region surrounding qnrs in pk245 is nearly i ... | 2006 | 16940067 |
| adaptive resistance and differential protein expression of salmonella enterica serovar enteritidis biofilms exposed to benzalkonium chloride. | the development of adaptive resistance of salmonella enterica serovar enteritidis atcc 4931 biofilms following exposure to benzalkonium chloride (bc) either continuously (1 microg ml(-1)) or intermittently (10 microg ml(-1) for 10 min daily) was examined. biofilms adapted to bc over a 144-h period could survive a normally lethal bc challenge (500 microg ml(-1) for 10 min) and then regrow, as determined by increases in biofilm thickness, total biomass, and the ratio of the viable biomass to the n ... | 2006 | 16940079 |
| a novel extended-spectrum tem-type beta-lactamase, tem-138, from salmonella enterica serovar infantis. | a novel natural tem beta-lactamase with extended-spectrum activity, tem-138, was identified in a ceftazidime-resistant clinical isolate of salmonella enterica serovar infantis. compared to tem-1, tem-138 contains the following mutations: e104k, n175i, and g238s. the bla(tem-138) gene was located on a 50-kb transferable plasmid. expression studies with escherichia coli revealed efficient ceftazidimase and cefotaximase activities for tem-138. | 2006 | 16940125 |
| genetic environment of quinolone resistance gene qnrb2 in a complex sul1-type integron in the newly described salmonella enterica serovar keurmassar. | a qnrb2 determinant was described for a new complex sul1-type integron from salmonella enterica serovar keurmassar. the genetic structure contained two class 1 integrons surrounding two common regions (crs) separated by a partial 3' conserved segment. the qnrb2 gene is adjacent to the first cr. | 2006 | 16940131 |
| nosocomial outbreak of extended-spectrum beta-lactamase-producing salmonella isangi in pediatric wards. | since may 2000, extended-spectrum beta-lactamase-producing (esbl) salmonella isangi were isolated from pediatric patients at a tertiary hospital. a total of 41 patients with positive cultures were reviewed, and the majority presented with gastroenteritis, fever, or both. one esbl phenotype was noted in all isolates, and clonality was confirmed by pulsed-field gel electrophoresis. this is the first report of salmonella sp. esbl resistance in our hospital. | 2006 | 16940846 |
| expression of a porphyromonas gingivalis hemagglutinin on the surface of a salmonella vaccine vector. | live, attenuated salmonella strains can serve as vectors for the delivery of recombinant vaccine antigens for development of oral mucosal vaccines. various vaccine parameters can affect the immune responses elicited by salmonella vectors, including the expression level, location and timing of expressed antigens. we have previously established immunogenic salmonella enterica serovar typhimurium strains which cytoplasmically express hemagglutinin b (hagb) of porphyromonas gingivalis, a putative pe ... | 2007 | 16942819 |
| shedding of foodborne pathogens by caenorhabditis elegans in compost-amended and unamended soil. | a study was done to characterize the shedding of foodborne pathogenic bacteria by caenorhabditis elegans, evaluate the persistence of worm populations cocultured with foodborne pathogens, and determine if c. elegans disperses ingested pathogens in soil as a result of shedding. escherichia. coli o157:h7, salmonella enterica serotype poona, and listeria monocytogenes, as well as e. coli op50, a non-pathogenic strain, were studied. synchronous populations of c. elegans were fed for 24 h on confluen ... | 2006 | 16942998 |
| prevalence and antimicrobial resistance of salmonella enteritidis and other salmonellas in the eggs and egg-storing trays from retail markets of coimbatore, south india. | a study was conducted to determine the incidence of salmonella enterica serovar enteritidis and other salmonella serovars on eggshell, egg contents and on egg-storing trays. a total of 492 eggs and 82 egg-storing trays were examined over a period of 1 year from different retail outlets of a residential area of coimbatore city, south india. salmonella contamination was recorded in 38 of 492 (7.7%) eggs out of which 29 was in eggshell (5.9%) and 9 in egg contents (1.8%). around 7.5% of the egg-sto ... | 2006 | 16943017 |
| the adherence of salmonella enteritidis pt4 to stainless steel: the importance of the air-liquid interface and nutrient availability. | biofilm formation on stainless steel by salmonella enterica serovar enteritidis pt4 during growth in three different nutritious conditions was studied. the ability of micro-organisms to generate biofilms on the stainless steel surfaces was studied for a total period of 18 days at 20 degrees c, under three different experimental treatments: (i) growth medium (tryptone soy broth) was not refreshed (no further nutrients were provided) during the incubation period, (ii) growth medium was renewed eve ... | 2006 | 16943077 |
| quantification of contamination of lettuce by gfp-expressing escherichia coli o157:h7 and salmonella enterica serovar typhimurium. | the primary objective of this study was to determine the possibility of internalization of gfp-expressing escherichia coli o157:h7 and salmonella enterica serovar typhimurium (s. typhimurium) strains mae 110 (multi-cellular morphology) and 119 (wild type morphology) into lettuce seedlings (lactuca sativa cv. tamburo) grown in an inoculated hydroponic and soil system. the second aim was to quantify the level of contamination with the use of a proper surface sterilization method. silver nitrate wa ... | 2007 | 16943102 |
| variable-number tandem repeats that are useful in genotyping isolates of salmonella enterica subsp. enterica serovars typhimurium and newport. | the genome of salmonella enterica subsp. enterica serovar typhimurium strain lt2 was analyzed for direct repeats, and 54 sequences containing variable-number tandem repeat loci were identified. ten primer pairs that anneal upstream and downstream of each selected locus were designed and used to amplify pcr targets in isolates of s. enterica serovars typhimurium and newport. four of the 10 loci did not show polymorphism in the length of products. six loci were selected for analysis. isolates of s ... | 2006 | 16943354 |
| multiplex pcr-based method for identification of common clinical serotypes of salmonella enterica subsp. enterica. | a multiplex pcr method has been developed to differentiate between the most common clinical serotypes of salmonella enterica subsp. enterica encountered in washington state and the united states in general. six genetic loci from s. enterica serovar typhimurium and four from s. enterica serovar typhi were used to create an assay consisting of two five-plex pcrs. the assays gave reproducible results with 30 different serotypes that represent the most common clinical isolates of s. enterica subsp. ... | 2006 | 16943358 |
| prevalence and antimicrobial resistance patterns of salmonella enterica in preweaned calves from dairies and calf ranches. | to evaluate serovar and antimicrobial resistance patterns of salmonella enterica isolated from preweaned calves and identify management risk factors associated with fecal shedding of s enterica. | 2006 | 16948605 |
| humanized transgenic mice expressing hla dr4-dq3 haplotype: reconstitution of phenotype and hla-restricted t-cell responses. | many autoimmune conditions have close genetic linkages to particular human histocompatibility leukocyte antigen (hla) class ii genes. with the aim of establishing a murine model of autoimmune disease, we have generated an hla dr4-dq3 haplotype transgenic (tg) mouse that expresses a 440-kb yeast artificial chromosome harbouring dra, drb1*040101, drb4*010301, dqa1*030101, dqb1*0302 and all the internal regulatory segments. this tg mouse line was crossed to human cd4 (hcd4) tg mice and endogenous c ... | 2006 | 16948641 |
| how to outwit the enemy: dendritic cells face salmonella. | salmonella enterica serovar typhi causes typhoid fever, a serious life-threatening systemic infection. in mice, a similar disease is caused by salmonella enterica serovar typhimurium. during typhoid fever, soon after attachment to the mucosal surface of the gut, bacteria come into contact with the dendritic cells (dcs). the ability to sample antigens, process and present them to naïve and mature t cells, in the context of major histocompatibility complex molecules, makes dcs indispensable for mo ... | 2006 | 16948811 |
| single, double and triple mutants of salmonella enterica serovar typhimurium degp (htra), degq (hhoa) and degs (hhob) have diverse phenotypes on exposure to elevated temperature and their growth in vivo is attenuated to different extents. | degp (htra) is a well-studied protease involved in survival of bacteria under stress conditions in vitro and in vivo. there are two paralogues of degp in the salmonella enterica serovar typhimurium genome, degq and degs. in order to understand more about the biological significance of this gene family, a series of deg-deletion mutants was generated in s. typhimurium strain sl3261 by allelic replacement. at elevated temperature in vitro, the viability of degp and degs mutants was reduced when com ... | 2006 | 16949246 |
| ctx-m-37 in salmonella enterica serotype isangi from durban, south africa. | beta-lactamase-mediated resistance was investigated in 59 putative extended-spectrum beta-lactamase (esbl)-positive salmonella spp. from the paediatric ward of a tertiary hospital in durban, south africa. three salmonella enterica serotype isangi cultured from stool samples were multidrug resistant, with susceptibility only to meropenem, piperacillin/tazobactam and cefoxitin. isoelectric focusing revealed beta-lactamases with isoelectric points of pi 5.8, 6.8 and 7.2. sequencing identified beta- ... | 2006 | 16949257 |
| molecular epidemiology of antimicrobial resistance among salmonella enterica serovar infantis from poultry in kagoshima, japan. | antimicrobial susceptibility and resistance genes of 135 strains of salmonella enterica serovar infantis isolated from poultry in kagoshima were examined. one strain (0.7%) was resistant to ampicillin (a), 97% to streptomycin (s), 95.6% to sulphamethoxazole (su), 96.3% to oxytetracycline (t), 11.1% to kanamycin (km) and 36.3% to ofloxacin (o). multiresistant phenotypes identified were assut-km, ssut-km, ssut-o and ssut. class 1 integrons were detected in 94.8% of isolates. approximately 89% of o ... | 2006 | 16949258 |
| catabolite repression of the sira regulatory cascade in salmonella enterica. | orthologs of the salmonella bara/sira two-component system are required for virulence, motility, secondary metabolism and stress survival throughout the gamma-proteobacteria. bara is a sensor kinase that responds to an unknown signal by phosphorylating the response regulator sira. sira increases the expression of genes within salmonella pathogenicity island 1 (spi1) that encode a type iii secretion system (ttss-1). sira does this by directly activating the hila and hilc regulatory genes encoded ... | 2006 | 16949866 |
| role of n-acetylglucosamine within core lipopolysaccharide of several species of gram-negative bacteria in targeting the dc-sign (cd209). | our recent studies have shown that the dendritic cell-specific icam nonintegrin cd209 (dc-sign) specifically binds to the core lps of escherichia coli k12 (e. coli), promoting bacterial adherence and phagocytosis. in this current study, we attempted to map the sites within the core lps that are directly involved in lps-dc-sign interaction. we took advantage of four sets of well-defined core lps mutants, which are derived from e. coli, salmonella enterica serovar typhimurium, neisseria gonorrhoea ... | 2006 | 16951363 |
| selective ablation of matrix metalloproteinase-2 exacerbates experimental colitis: contrasting role of gelatinases in the pathogenesis of colitis. | the matrix metalloproteinases (mmps), mmp-2 and mmp-9, share structural and substrate similarities and are up-regulated during human as well as animal models of inflammatory bowel disease. we recently demonstrated that epithelial-derived mmp-9 is an important mediator of inflammation and tissue damage in colitis. in this study, we examined the role of mmp-2 in acute colitis. colitis was induced using two models, administration of dextran sodium sulfate (dss) and salmonella enterica subsp. serova ... | 2006 | 16951375 |
| characterization of stg fimbriae from an avian pathogenic escherichia coli o78:k80 strain and assessment of their contribution to colonization of the chicken respiratory tract. | in a previous study, ecs-3, a sequence from avian pathogenic escherichia coli (apec) o78:k80 strain chi7122, was found to be expressed in vivo in infected chicken tissues. the region encompassing ecs-3 carries a fimbrial gene cluster that is a putative ortholog of the stg fimbrial gene cluster of salmonella enterica serovar typhi. this apec fimbrial gene cluster, which we have termed stg, is a member of a distinct group of related fimbriae that are located in the glms-psts intergenic region of c ... | 2006 | 16952934 |
| flit acts as an anti-flhd2c2 factor in the transcriptional control of the flagellar regulon in salmonella enterica serovar typhimurium. | flagellar operons are divided into three classes with respect to their transcriptional hierarchy in salmonella enterica serovar typhimurium. the class 1 gene products flhd and flhc act together in an flhd(2)c(2) heterotetramer, which binds upstream of the class 2 promoters to facilitate binding of rna polymerase. class 2 expression is known to be enhanced by a disruption mutation in a flagellar gene, flit. in this study, we purified flit protein in a his-tagged form and showed that the protein p ... | 2006 | 16952964 |
| the key role of pulsed-field gel electrophoresis in investigation of a large multiserotype and multistate food-borne outbreak of salmonella infections centered in pennsylvania. | five different serotypes of salmonella enterica were implicated in a large outbreak linked to fresh roma tomatoes served at gas station deli counters in pennsylvania and nearby states during july 2004: s. enterica serotypes javiana, anatum, thompson, typhimurium, and muenchen. one of these serotypes, anatum, was isolated from both tomatoes and patients. pulsed-field gel electrophoresis (pfge) played a key role in identifying the outbreak-associated isolates and distinguishing them from unrelated ... | 2006 | 16954249 |
| comparison of api 20e and inva pcr for identification of salmonella enterica isolates from swine production units. | api 20e and inva pcr were evaluated for the identification of salmonella enterica isolates from swine farms. api 20e had the highest agreement with other tests at the 99.9% likelihood level. both tests had 100% sensitivity and 96% specificity compared to 16s rrna sequencing. compared to serotyping, both tests had 96% sensitivity; specificity was 86% for api 20e and 79% for inva pcr. | 2006 | 16954281 |
| survival of salmonella enterica serovar newport in manure and manure-amended soils. | salmonella enterica serovar newport has undergone a rapid epidemic spread in dairy cattle. this provides an efficient mechanism for pathogen amplification and dissemination into the environment through manure spreading on agricultural land. the objective of this study was to determine the survival characteristics of salmonella serovar newport in manure and manure-amended soils where the pathogen may be amplified. a multidrug-resistant (mdr) salmonella serovar newport strain and a drug-susceptibl ... | 2006 | 16957193 |
| comparison of salmonella enterica serovar typhimurium lt2 and non-lt2 salmonella genomic sequences, and genotyping of salmonellae by using pcr. | genes of salmonella enterica serovar typhimurium lt2 expected to be specifically present in salmonella were selected using the basic local alignment search tool (blast) program. the 152 selected genes were compared with 11 genomic sequences of salmonella serovars, including salmonella enterica subsp. i and iiib and salmonella bongori (v), and were clustered into 17 groups by their comparison patterns. a total of 38 primer pairs were constructed to represent each of the 17 groups, and pcr was per ... | 2006 | 16957240 |
| microarray-based detection of bacteria by on-chip pcr. | in this chapter, a protocol called on-chip polymerase chain reaction (pcr) is presented for the deoxyribonucleic acid (dna) microarray-based detection of bacterial target sequences. on-chip pcr combines, in a single step, the conventional amplification of a target with a simultaneous, nested pcr round intended for target detection. while freely diffusible primers are deployed for amplification, the nested pcr is initiated by oligonucleotide primers bound to a solid phase. thus, on-chip pcr allow ... | 2006 | 16957345 |
| identification and characterization of espk, a type iii secreted effector protein of enterohaemorrhagic escherichia coli o157:h7. | enterohaemorrhagic escherichia coli (ehec) causes bloody diarrhoea in humans and deploys a type iii secretion system (t3ss) encoded by the locus of enterocyte effacement to elicit the formation of attaching and effacing (ae) lesions on intestinal epithelia. here, we report the identification of a new secreted substrate of this system, z1829, which is encoded by cryptic prophage cp-933n. elevated secretion of a beta-lactamase-z1829 fusion protein was detected upon mutation of sepd in ehec o157:h7 ... | 2006 | 16958848 |
| nucleotide sequences and organization of the genes for carotovoricin (ctv) from erwinia carotovora indicate that ctv evolved from the same ancestor as salmonella typhi prophage. | carotovoricin er (ctver), which is produced by a plant soft rot disease causative agent, erwinia carotovora subsp. carotovora er, is a high-molecular-weight bacteriocin showing myoviridae phage-tail-like morphology with contractile sheath and plural tail fibers. we determined the complete nucleotide sequences of ctver genes on the e. carotovora er chromosome and report that ctver genes consist of lysis cassette, major and minor structural protein gene clusters. four promoters were identified. th ... | 2006 | 16960352 |
| salmonella enterica serotype virchow: epidemiology, resistance patterns and molecular characterisation of an invasive salmonella serotype in israel. | this study outlines the unique epidemiology of salmonella enterica serotype virchow in israel. between 1997 and 2002, the overall incidence of non-typhoid salmonella enterica (nts) decreased from 69.3 to 53.3 infections/100,000 population, but the incidence of s. virchow increased (from 7.2 to 9.1 infections/100,000). since 2000, s. virchow has become the second-ranking nts isolate, accounting for 17% and 27% of all stool and blood nts isolates, respectively. infants aged < 1 year had the highes ... | 2006 | 16961637 |
| identification of specific gene sequences conserved in contemporary epidemic strains of salmonella enterica. | genetic elements specific to recent and contemporary epidemic strains of salmonella enterica were identified using comparative genomic analysis. two epidemic multidrug-resistant (mdr) strains, mdr salmonella enterica serovar typhimurium definitive phage type 104 (dt104) and cephalosporin-resistant mdr salmonella enterica serovar newport, and an epidemic pansusceptible strain, salmonella serovar typhimurium dt160, were subjected to salmonella gene microarray and suppression subtractive hybridizat ... | 2006 | 16963552 |
| bile-induced curing of the virulence plasmid in salmonella enterica serovar typhimurium. | exposure to bile induces curing of the virulence plasmid in salmonella enterica serovar typhimurium (pslt). disruption of the ccdb gene increases pslt curing, both spontaneous and induced by bile, suggesting that the pslt ccdab genes may encode a homolog of the ccdab addiction module previously described in the f sex factor. unlike the f sex factor, synthesis of pslt-encoded pili does not confer bile sensitivity. these observations may provide insights into the evolution of virulence plasmids in ... | 2006 | 16963576 |
| variant salmonella genomic island 1-l antibiotic resistance gene cluster in salmonella enterica serovar newport. | we report a new salmonella genomic island 1 variant antibiotic resistance gene cluster called sgi1-l in a salmonella enterica serovar newport isolate containing a dfra15 gene cassette conferring resistance to trimethoprim. the isolate carried another class 1 integron containing the aacc5 and aada7 gene cassettes conferring resistance to gentamicin and streptomycin/spectinomycin, respectively. | 2006 | 16966396 |
| mycobacterium tuberculosis-susceptible i/st mice develop severe disease following infection with taxonomically distant bacteria, salmonella enterica and chlamydia pneumoniae. | mice of i/st strain develop severe lung inflammation and die shortly following infection with virulent mycobacteria. to find out whether tuberculosis (tb)-susceptible i/st mice are susceptible to other intracellular bacteria, we investigated two different taxonomically distant pathogens, chlamydia pneumoniae and salmonella enterica serovar typhimurium. comparison of i/st and tb-resistant a/sn mice (both nramp1(r)) demonstrated that the former are more susceptible to both salmonella and chlamydia ... | 2006 | 16968403 |
| binding-induced stabilization and assembly of the phage p22 tail accessory factor gp4. | to infect and replicate, bacteriophage p22 injects its 43 kbp genome across the cell wall of salmonella enterica serovar typhimurium. the attachment of phage p22 to the host cell as well as the injection of the viral dna into the host is mediated by the virion's tail complex. this 2.8 mda molecular machine is formed by five proteins, which include the portal protein gp1, the adhesion tailspike protein gp9, and three tail accessory factors: gp4, gp10, gp26. we have isolated the tail accessory fac ... | 2006 | 16970964 |
| phenotypic and genotypic differentiation of porcine salmonella enterica subsp. enterica serovar derby isolates. | sixty-two salmonella enterica subsp. enterica serovar derby isolates from slaughter pigs and meat products isolated in southern brazil were analyzed for their genomic relationships and for the presence of antimicrobial resistance genes. twenty-four s. derby isolates were indistinguishable by their subtracted restriction fingerprinting (srf) pattern, xbai- and blni-macrorestriction patterns, phage type, plasmid profile, and resistance pattern. in contrast to the blni-macrorestriction patterns, th ... | 2006 | 16971066 |
| the presence of major world-wide clones for phage type 4 and 8 salmonella enterica serovar enteritidis and the evaluation of their virulence levels by invasiveness assays in vitro and in vivo. | seventy-seven animal isolates of salmonella enterica serovar enteritidis (s. enteritidis) obtained from the united states were analyzed by phage typing and pulsed field gel electrophoresis (pfge). thirty-nine strains were found with phage types (pt) 4, 8, and 13a. when the chromosomal dna of these 39 isolated strains with pt4, 8, and 13a were digested with xbai, spei and noti, followed by pfge analysis, 28 strains were found with a pattern combination of x4s4n4, which was the major subtype. when ... | 2006 | 16978349 |
| gene expression responses to a salmonella infection in the chicken intestine differ between lines. | poultry products are an important source of salmonella enterica. an effective way to reduce food poisoning due to salmonella would be to breed chickens more resistant to salmonella. unfortunately host responses to salmonella are complex with many factors involved. to learn more about responses to salmonella in young chickens, a cdna microarray analysis was performed to compare gene expression profiles between two chicken lines under control and salmonella infected conditions. newly hatched chick ... | 2006 | 16978708 |
| multidrug-resistant and extended-spectrum beta-lactamase (esbl)-producing salmonella enterica (serotypes typhi and paratyphi a) from blood isolates in nepal: surveillance of resistance and a search for newer alternatives. | we evaluated the prevalence of multidrug resistance (mdr) and production of extended spectrum beta-lactamase (esbl) by salmonella enterica (serotypes typhi and paratyphi a) in a teaching hospital in nepal. the mdr strains of s. enterica were also tested for susceptibility to newer antibiotics. | 2006 | 16978898 |
| simulation model estimates of test accuracy and predictive values for the danish salmonella surveillance program in dairy herds. | the danish government and cattle industry instituted a salmonella surveillance program in october 2002 to help reduce salmonella enterica subsp. enterica serotype dublin (s. dublin) infections. all dairy herds are tested by measuring antibodies in bulk tank milk at 3-month intervals. the program is based on a well-established elisa, but the overall test program accuracy and misclassification was not previously investigated. we developed a model to simulate repeated bulk tank milk antibody measur ... | 2006 | 16979767 |
| transcription modulation of salmonella enterica serovar typhimurium promoters by sub-mic levels of rifampin. | promoter-lux fusions that showed rifampin-modulated transcription were identified from a salmonella enterica serovar typhimurium 14028 reporter library. the transformation of a subset of fusions into mutants that lacked one of six global regulatory proteins or were rifampin resistant showed that transcription modulation was independent of the global regulators, promoter specific, and dependent on the interaction of rifampin with rna polymerase. | 2006 | 16980465 |
| salmonella enterica serovar typhimurium periplasmic superoxide dismutase sodci is a member of the phopq regulon and is induced in macrophages. | salmonella enterica serovar typhimurium replicates within host macrophages during the systemic stage of infection. in the macrophage, the bacteria must survive the respiratory burst that produces superoxide. serovar typhimurium strain 14028 produces two periplasmic superoxide dismutases, sodci and sodcii, but only sodci contributes to virulence. although we have shown that this is primarily due to differences in the two proteins, evidence suggests differential regulation of the two genes. using ... | 2006 | 16980468 |
| uncovering a large set of genes that affect surface motility in salmonella enterica serovar typhimurium. | we describe a large set of genes affecting motility in salmonella enterica serovar typhimurium. identified in microarray experiments as displaying flagellar gene expression patterns or controlled by known flagellar regulators, we show that null mutations in these genes primarily affect swarming motility. three genes function in chemotaxis. | 2006 | 16980469 |
| purf-independent phosphoribosyl amine formation in yjgf mutants of salmonella enterica utilizes the tryptophan biosynthetic enzyme complex anthranilate synthase-phosphoribosyltransferase. | in salmonella enterica, the biosynthetic pathways for the generation of purines and the essential cofactor thiamine pyrophosphate branch after sharing five enzymatic steps. phosphoribosyl amine (pra) is the first intermediate in the common portion of the pathway and is generated from phosphoribosylpyrophosphate and glutamine by the purf enzyme (phosphoribosylpyrophosphate amidotransferase). a null mutation in yjgf allows purf-independent pra formation by an unknown mechanism. the tryptophan bios ... | 2006 | 16980480 |
| phop-induced genes within salmonella pathogenicity island 1. | the invasive pathogen salmonella enterica has evolved a sophisticated device that allows it to enter nonphagocytic host cells. this process requires the expression of salmonella pathogenicity island 1 (spi-1), which encodes a specialized type iii protein secretion system (ttss). this ttss delivers a set of effectors that produce a marked rearrangement of the host cytoskeleton, generating a profuse membrane ruffling at the site of interaction, driving bacterial entry. it has been shown that the p ... | 2006 | 16980492 |
| prevalence of antibodies reactive to pathogenic and nonpathogenic bacteria in preimmune serum of new zealand white rabbits. | polyclonal antibodies are typically produced in rabbits. the rabbit's health plays an important role in the quality of antibodies produced. therefore, recommendations have been made by organizations on which bacteria and how frequently to test rabbit colonies. since it is well known that rabbits may contain cross-reactive antibodies in their preimmune serum, it is common to test the rabbits for reactivity prior to immunization. here preimmune sera from 19 different rabbits were tested with elisa ... | 2006 | 16981648 |
| characterization of the acyl substrate binding pocket of acetyl-coa synthetase. | amp-forming acetyl-coa synthetase [acs; acetate:coa ligase (amp-forming), ec 6.2.1.1] catalyzes the activation of acetate to acetyl-coa in a two-step reaction. this enzyme is a member of the adenylate-forming enzyme superfamily that includes firefly luciferase, nonribosomal peptide synthetases, and acyl- and aryl-coa synthetases/ligases. although the structures of several superfamily members demonstrate that these enzymes have a similar fold and domain structure, the low sequence conservation an ... | 2006 | 16981708 |
| cxcl16 regulates cell-mediated immunity to salmonella enterica serovar enteritidis via promotion of gamma interferon production. | cxcl16 is a recently discovered multifaceted chemokine that has been shown not only to recruit activated t lymphocytes but also to play a direct role in the binding and phagocytosis of bacteria by professional antigen-presenting cells. in this study, we investigated the role of cxcl16 in vivo in the regulation of the immune response using a murine model of salmonella enterica serovar enteritidis infection. the expression of cxcl16 was strongly upregulated in the spleens and livers of animals dev ... | 2006 | 16982830 |
| a recombinant attenuated salmonella enterica serovar typhimurium vaccine encoding eimeria acervulina antigen offers protection against e. acervulina challenge. | coccidiosis is a ubiquitous disease caused by intestinal protozoan parasites belonging to several distinct species of the genus eimeria. cell-mediated immunity (cmi) is critically important for protection against eimeria; thus, our approach utilizes the bacterial type iii secretion system (ttss) to deliver an antigen directly into the cell cytoplasm of the immunized host and into the major histocompatibility complex class i antigen-processing pathway for induction of cmi and antigen-specific cyt ... | 2006 | 16982843 |
| caveolin-1-deficient mice show defects in innate immunity and inflammatory immune response during salmonella enterica serovar typhimurium infection. | a number of studies have shown an association of pathogens with caveolae. to this date, however, there are no studies showing a role for caveolin-1 in modulating immune responses against pathogens. interestingly, expression of caveolin-1 has been shown to occur in a regulated manner in immune cells in response to lipopolysaccharide (lps). here, we sought to determine the role of caveolin-1 (cav-1) expression in salmonella pathogenesis. cav-1(-/-) mice displayed a significant decrease in survival ... | 2006 | 16982844 |
| development of a real-time pcr assay for detection of gyra mutations associated with reduced susceptibility to ciprofloxacin in salmonella enterica serovar typhi and paratyphi a. | a real-time pcr assay with the cycling probe method was used to detect mutations at codons 83 and 87 in the dna gyrase a subunit encoded by gyra in salmonella enterica serovar typhi and paratyphi a clinical isolates. the susceptibility estimated from the results of the gyra mutation assay was consistent with that identified by the culture method using an e-test. this assay allows rapid screening of s. enterica serovar typhi and paratyphi a with reduced susceptibility to ciprofloxacin. | 2006 | 16985292 |
| inhibition of fructose-1,6-bisphosphatase by aminoimidazole carboxamide ribotide prevents growth of salmonella enterica purh mutants on glycerol. | the enzyme fructose-1,6-bisphosphatase (fbp) is key regulatory point in gluconeogenesis. mutants of salmonella enterica lacking purh accumulate 5-amino-4-imidazole carboxamide ribotide (aicar) and are unable to utilize glycerol as sole carbon and energy sources. the work described here demonstrates this lack of growth is due to inhibition of fbp by aicar. mutant alleles of fbp that restore growth on glycerol encode proteins resistant to inhibition by aicar and the allosteric regulator amp. this ... | 2006 | 16987812 |
| optimization of the delivery of heterologous proteins by the salmonella enterica serovar typhimurium type iii secretion system for vaccine development. | type iii protein secretion systems, which are organelles with the capacity to deliver bacterial proteins into host cells, have been adapted to deliver heterologous antigens for vaccine development. a limitation of these antigen delivery systems is that some proteins are not amenable to secretion through this pathway. we show here that proteins from the simian and human immunodeficiency viruses that are not permissive for secretion through a salmonella enterica serovar typhimurium type iii secret ... | 2006 | 16988261 |
| down-regulation of key virulence factors makes the salmonella enterica serovar typhimurium rfah mutant a promising live-attenuated vaccine candidate. | mutants of salmonella enterica serovar typhimurium that lack the transcriptional regulator rfah are efficient as live oral vaccines against salmonellosis in mice. we show that the attenuation of the vaccine candidate strain is associated with reduced net growth in epithelial and macrophage cells. in order to identify the relevant rfah-dependent genes, the rfah regulon was determined with s. enterica serovars enteritidis and typhimurium using whole-genome salmonella microarrays. as well as impact ... | 2006 | 16988271 |
| thermal injury and recovery of salmonella enterica serovar enteritidis in ground chicken with temperature, ph, and sodium chloride as controlling factors. | cells of salmonella enterica serovar enteritidis were grown at 25 and 35 degrees c, heat injured (55, 60, and 62.5 degrees c), and recovered in tryptic soy broth (tsb) at various nacl concentrations (2.0 and 3.5%) and ph levels (5.5 and 6.5). to assess the interactions of growth temperature, heating temperature, nacl concentration and ph on the thermal injury and recovery of salmonella enteritidis in ground chicken, a randomized design with each experimental combination was used. when a logistic ... | 2006 | 16995506 |
| inhibitory effects of enterococcus strains obtained from a probiotic product on in vitro growth of salmonella enterica serovar enteritidis strain ifo3313. | enterococcus faecium and enterococcus gallinarum strains were isolated from a commercial probiotic product and the effects of these strains on the growth of salmonella enterica serovar enteritidis strain ifo3313 were investigated. viable cell counts of salmonella enteritidis in mixed cultures with the probiotic product isolate of e. faecium were significantly (p < 0.05) lower than those in pure cultures after 6, 8, and 24 h when the cultures were incubated in heart infusion broth at 37 and 41 de ... | 2006 | 16995534 |
| dna adenine methylation regulates virulence gene expression in salmonella enterica serovar typhimurium. | transcriptomic analyses during growth in luria-bertani medium were performed in strain sl1344 of salmonella enterica serovar typhimurium and in two isogenic derivatives lacking dam methylase. more genes were repressed than were activated by dam methylation (139 versus 37). key genes that were differentially regulated by dam methylation were verified independently. the largest classes of dam-repressed genes included genes belonging to the sos regulon, as previously described in escherichia coli, ... | 2006 | 16997949 |
| roles for dna supercoiling and the fis protein in modulating expression of virulence genes during intracellular growth of salmonella enterica serovar typhimurium. | adaptation of bacterial pathogens to an intracellular environment requires resetting of the expression levels of a wide range of both virulence and housekeeping genes. we investigated the possibility that changes in dna supercoiling could modulate the expression of genes known to be important in the intracellular growth of the pathogen salmonella enterica serovar typhimurium. our data show that dna becomes relaxed when salmonella grows in murine macrophage but not in epithelial cells, indicating ... | 2006 | 16999831 |
| loss of hfq activates the sigmae-dependent envelope stress response in salmonella enterica. | ubiquitous rna-binding protein hfq mediates the regulatory activity of many small rnas (srnas) in bacteria. to identify potential targets for hfq-mediated regulation in salmonella, we searched for lacz translational fusions whose activity varied in the presence or absence of hfq. fusions downregulated by hfq were more common than fusions showing the opposite response. surprisingly, in a subset of isolates from the major class, the higher activity in the absence of hfq was due to transcriptional ... | 2006 | 16999834 |
| the flin-flih interaction mediates localization of flagellar export atpase flii to the c ring complex. | flih regulates the flagellar export atpase flii, preventing nonproductive atp hydrolysis. flih has been shown to stably associate with the c ring protein flin. analysis of this complex reveals that flih is required for flii localization to the c ring, and thus flih not only inhibits flii atpase activity but also may act to target flii to the basal body. quantitative binding studies revealed a kd of 110 nm for flih binding to flin. the kd for flih binding of a flin variant from a temperature-sens ... | 2006 | 17002279 |
| molecular characterization and occurrence of extended-spectrum beta-lactamase resistance genes among salmonella enterica serovar corvallis from thailand, bulgaria, and denmark. | fifty nine salmonella corvallis isolates from humans and food products in bulgaria, denmark, and thailand were examined for antimicrobial susceptibility and characterized by pulsed-field gel electrophoresis (pfge). cephalosporin-resistant isolates were examined for the presence of genes encoding beta-lactamases by pcr and sequencing. ten different pfge types were observed. one type (30 isolates) was recovered in all three countries; three types were found only in bulgaria, two only in denmark, t ... | 2006 | 17002546 |
| clonal variation in xenorhabdus nematophila virulence and suppression of manduca sexta immunity. | virulence of the insect pathogen xenorhabdus nematophila is attributed in part to its ability to suppress immunity. for example, x. nematophila suppresses transcripts encoding several antimicrobial proteins, even in the presence of salmonella enterica, an inducer of these transcripts. we show here that virulence and immune suppression phenotypes can be lost in a subpopulation of x. nematophila. cells that have undergone 'virulence modulation' (vmo) have attenuated virulence and fail to suppress ... | 2007 | 17002783 |
| linkage of avian and reproductive tract tropism with sequence divergence adjacent to the 5s ribosomal subunit rrfh of salmonella enterica. | the 183 bp between the end of the 23s rrlh rrna gene and the start of the 5s rrfh rrna gene (isr-1) and the 197 bp between the end of the rrfh rrna gene and the start of the transfer rna aspu (isr-2) of salmonella enterica ssp. enterica serotypes enteritidis, typhimurium, pullorum, heidelberg, gallinarum, typhi and choleraesuis were compared. isr-1s of d1 serotypes (pullorum, gallinarum and enteritidis), b serotypes (typhimurium and heidelberg) and the c2 serotype newport and the enteric fever p ... | 2006 | 17005008 |
| introducing vi polysaccharide typhoid fever vaccine to primary school children in north jakarta, indonesia, via an existent school-based vaccination platform. | to report results on coverage, safety and logistics of a large-scale, school-based vi polysaccharide immunization campaign in north jakarta. | 2006 | 17005220 |
| ling, a new integron-associated gene cassette encoding a lincosamide nucleotidyltransferase. | 2006 | 17005845 | |
| multidrug-resistant salmonella enterica serovar typhi isolates with high-level resistance to ciprofloxacin in dhaka, bangladesh. | 2006 | 17005846 | |
| the rcs phosphorelay system is specific to enteric pathogens/commensals and activates ydei, a gene important for persistent salmonella infection of mice. | bacteria utilize phosphorelay systems to respond to environmental or intracellular stimuli. salmonella enterica encodes a four-step phosphorelay system that involves two sensor kinase proteins, rcsc and rcsd, and a response regulator, rcsb. the physiological stimulus for rcs phosphorelay activation is unknown; however, rcs-regulated genes can be induced in vitro by osmotic shock, low temperature and antimicrobial peptide exposure. in this report we investigate the role of the rcs pathway using p ... | 2006 | 17010160 |
| rapid aerosol transmission of salmonella among turkeys in a simulated holding-shed environment. | once turkeys arrive at midwest processing plants, they are usually held in large open-sided sheds for 1 to 4 h, waiting to be unloaded. in hot, humid weather, large fans are used to cool the birds. the resultant air currents distribute a significant amount of dust to the turkeys. the dust created in this environment could be a factor in the number of salmonella-contaminated turkeys entering slaughter plants. the objective of this study was to determine if rapid transmission of salmonella in turk ... | 2006 | 17012158 |
| comparative genetics of the rdar morphotype in salmonella. | the salmonella rdar morphotype is a distinct, rough and dry colony morphology formed by the extracellular interaction of thin aggregative fimbriae (tafi or curli), cellulose, and other polysaccharides. cells in rdar colonies are more resistant to desiccation and exogenous stresses, which is hypothesized to aid in the passage of pathogenic salmonella spp. between hosts. here we analyzed the genetic and phenotypic conservation of the rdar morphotype throughout the entire salmonella genus. the rdar ... | 2006 | 17012381 |
| cases of typhoid fever imported into england, scotland and wales (2000-2003). | although typhoid fever is no longer endemic in most of the developed world, it remains a major infectious disease in less developed regions and imported cases continue to occur in returning travellers, immigrants or migrant workers. we analysed all 692 isolates of salmonella enterica subspecies enterica serovar typhi from cases in england, scotland and wales that were sent to the laboratory of enteric pathogens at the health protection agency, centre for infections, london, uk between 2000 and 2 ... | 2007 | 17014877 |
| the translocated salmonella effector proteins ssef and sseg interact and are required to establish an intracellular replication niche. | the facultative intracellular pathogen salmonella enterica causes a variety of diseases, including gastroenteritis and typhoid fever. inside epithelial cells, salmonella replicates in vacuoles, which localize in the perinuclear area in close proximity to the golgi apparatus. among the effector proteins translocated by the salmonella pathogenicity island 2-encoded type iii secretion system, sifa and sseg have been shown necessary but not sufficient to ensure the intracellular positioning of salmo ... | 2006 | 17015457 |
| the three-dimensional structure of the flagellar rotor from a clockwise-locked mutant of salmonella enterica serovar typhimurium. | three-dimensional reconstructions from electron cryomicrographs of the rotor of the flagellar motor reveal that the symmetry of individual m rings varies from 24-fold to 26-fold while that of the c rings, containing the two motor/switch proteins flim and flin, varies from 32-fold to 36-fold, with no apparent correlation between the symmetries of the two rings. results from other studies provided evidence that, in addition to the transmembrane protein flif, at least some part of the third motor/s ... | 2006 | 17015643 |
| [salmonella serotype mbandaka food-borne outbreak]. | 2006 | 17020690 | |
| comparison of subtyping methods for differentiating salmonella enterica serovar typhimurium isolates obtained from food animal sources. | molecular characterization (e.g., dna-based typing methods) of salmonella isolates is frequently employed to compare and distinguish clinical isolates recovered from animals and from patients with food-borne disease and nosocomial infections. in this study, we compared the abilities of different phenotyping and genotyping methods to distinguish isolates of salmonella enterica serovar typhimurium from different food animal sources. one hundred twenty-eight s. enterica serovar typhimurium strains ... | 2006 | 17021084 |
| molecular basis of resistance displayed by highly ciprofloxacin-resistant salmonella enterica serovar typhi in bangladesh. | highly ciprofloxacin-resistant (mic, 512 microg/ml) strains of salmonella enterica serovar typhi were isolated from the blood of typhoid patients in dhaka, bangladesh. the strains were indistinguishable by their antibiograms, biotypes, and variable-number tandem repeat types and had matching point mutations at positions 83 and 87 of the gyra gene. the isolation of these strains in an area of high endemicity indicates the need for continuous surveillance of antibiotic resistance of s. enterica se ... | 2006 | 17021117 |
| general model, based on two mixed weibull distributions of bacterial resistance, for describing various shapes of inactivation curves. | cells of listeria monocytogenes or salmonella enterica serovar typhimurium taken from six characteristic stages of growth were subjected to an acidic stress (ph 3.3). as expected, the bacterial resistance increased from the end of the exponential phase to the late stationary phase. moreover, the shapes of the survival curves gradually evolved as the physiological states of the cells changed. a new primary model, based on two mixed weibull distributions of cell resistance, is proposed to describe ... | 2006 | 17021197 |
| genetic and phenotypic variability among salmonella enterica serovar typhimurium isolates from california dairy cattle and humans. | fifty-six human and 24 adult dairy cattle isolates of salmonella enterica serovar typhimurium from a single county in california were compared using ribotyping, insertion sequence typing (is200), pulsed-field gel electrophoresis, plasmid typing, phage typing, and antimicrobial resistance testing. the majority of the isolates fell into one of two groups which were phage types dt104 and dt193. combining the information from all typing methods, a total of 45 different "clusters" were defined, with ... | 2006 | 17021214 |
| multiple regulators of the flavohaemoglobin (hmp) gene of salmonella enterica serovar typhimurium include rama, a transcriptional regulator conferring the multidrug resistance phenotype. | microbial flavohaemoglobins are proteins with homology to haemoglobins from higher organisms, but clearly linked to nitric oxide (no) metabolism by bacteria and yeast. hmp mutant strains of several bacteria are hypersensitive to no and related compounds and hmp genes are up-regulated by the presence of no. the regulatory mechanisms involved in hmp induction by no and the superoxide-generating agent, methyl viologen (paraquat; pq), are complex, but progressively being resolved. here we show for t ... | 2007 | 17024490 |
| evaluation of 1mds electropositive microfilters for simultaneous recovery of multiple microbe classes from tap water. | the 1mds electropositive microfilter was designed specifically for virus capture and recovery from water, but its electrostatic properties raise the possibility that 1mds filters can also effectively capture bacteria and parasites present in water samples. this filter is recommended by united states environmental protection agency (usepa) for recovering human enteric viruses from water matrices through the virus adsorption-elution (viradel) technique. if bacteria and parasites can also be concen ... | 2007 | 17027108 |
| involvement of caspase-3, lipid peroxidation and tnf-alpha in causing apoptosis of macrophages by coordinately expressed salmonella phenotype under stress conditions. | invasive salmonella has been reported to induce apoptosis of macrophages as a part of its infection process, which may allow it to avoid detection by the innate immune system. however, the bacterial components capable of inducing apoptosis, particularly under the environments offered by the host have not been fully identified. therefore, in the present study, attempts were made to evaluate the apoptotic potential of salmonella enterica serovar typhi (s. typhi) outer membrane protein expressed un ... | 2007 | 17027970 |
| multilocus sequence typing supports the hypothesis that cow- and human-associated salmonella isolates represent distinct and overlapping populations. | a collection of 179 human and 156 bovine clinical salmonella isolates obtained from across new york state over the course of 1 year was characterized using serotyping and a multilocus sequence typing (mlst) scheme based on the sequencing of three genes (fima, manb, and mdh). the 335 isolates were differentiated into 52 serotypes and 72 sequence types (sts). analyses of bovine isolates collected on different farms over time indicated that specific subtypes can persist over time on a given farm; i ... | 2006 | 17028236 |
| molecular characterisation of salmonella strains by an oligonucleotide multiprobe microarray. | a dna microarray has been developed for the simultaneous characterisation and typing of salmonella enterica subsp. enterica isolates. one-hundred and nine 35-40 mer oligonucleotides probes detect flagellar and somatic antigen encoding genes (serogroup or serotype specific), important virulence genes located within or outside the pathogenicity islands, phage-associated genes and antibiotic resistance determinants. the probes were printed on glass slides and whole genomic cy5-labelled salmonella d ... | 2007 | 17029709 |
| assessment of factors contributing to changes in the incidence of antimicrobial drug resistance in salmonella enterica serotypes enteritidis and typhimurium from humans in england and wales in 2000, 2002 and 2004. | an investigation into changes in the occurrence of antimicrobial resistance in salmonella enterica serotypes enteritidis and typhimurium from human infection in england and wales in 2000, 2002 and 2004 has shown that the incidence of strains of s. enteritidis with resistance to nalidixic acid coupled with decreased susceptibility to ciprofloxacin has more than doubled between 2000 and 2004, whereas the overall levels of resistance in s. typhimurium have fallen by ca. 25%. in relation to publishe ... | 2006 | 17029756 |
| modification of enrofloxacin treatment regimens for poultry experimentally infected with salmonella enterica serovar typhimurium dt104 to minimize selection of resistance. | we hypothesized that higher doses of fluoroquinolones for a shorter duration could maintain efficacy (as measured by reduction in bacterial count) while reducing selection in chickens of bacteria with reduced susceptibility. chicks were infected with salmonella enterica serovar typhimurium dt104 and treated 1 week later with enrofloxacin at the recommended dose for 5 days (water dose adjusted to give 10 mg/kg of body weight of birds or equivalence, i.e., water at 50 ppm) or at 2.5 or 5 times the ... | 2006 | 17030564 |
| cytokine expression in chicken peripheral blood mononuclear cells after in vitro exposure to salmonella enterica serovar enteritidis. | cytokines are secreted proteins involved with cell recruitment and regulation of both innate and adaptive immune responses. they are essential for an effective host immune response to pathogens. the objective of this study was to determine the effect of salmonella enterica serovar enteritidis (s. enteritidis) exposure and genetic line on cytokine mrna expression level of cultured chicken peripheral blood mononuclear cells (pbmc). interleukin-2, interleukin-6 (il-6), cxcli2, and transforming grow ... | 2006 | 17032822 |
| differential effect of auxotrophies on the release of macromolecules by salmonella enterica vaccine strains. | attenuated salmonella enterica strains have been widely used as live carriers for vaccines and therapeutic molecules. appropriate attenuation has been introduced into such bacteria for safety reasons and the improvement of strain properties. here, we compared two strains that were rendered auxotroph for diaminopimelic acid or thymidine monophosphate precursors by deletion of the genes asd or thya, respectively. upon removal of the complementing compound from bacterial cultures, both strains quic ... | 2006 | 17034415 |
| antimicrobial resistance in salmonella enterica serovar dublin isolates from beef and dairy sources. | salmonella enterica serovar dublin (s. dublin) is a cattle-adapted salmonella serovar, so if antimicrobial resistance in s. dublin arises as a result of antimicrobial use this most likely occurs within the cattle reservoir without impact from antimicrobial use in humans. we tested the antimicrobial resistance of bovine-origin s. dublin isolates from 1986 through 2004 using a standard disk diffusion method. high proportions of isolates throughout the time period were resistant to one or more anti ... | 2007 | 17034963 |
| genetic determinants of acute inflammation regulate salmonella infection and modulate slc11a1 gene (formerly nramp1) effects in selected mouse lines. | two lines of mice selected to produce maximal (airmax) or minimal (airmin) acute inflammatory reactions (air) differ in their susceptibility to infection by salmonella enterica serotype typhimurium (s. typhimurium). the ld(50) for airmax mice is 1000 times higher than that observed for airmin mice, and higher frequencies of slc11a1 alleles (known to confer either resistance (r) or high susceptibility (s) to s. typhimurium) were consistently found in airmax and airmin mouse lines, respectively. i ... | 2006 | 17035062 |
| effects of nonimmunized egg yolk powder-supplemented feed on salmonella enteritidis prevention and elimination in broilers. | chicken consumption is a newly identified risk factor in salmonella enterica serovar enteritidis (se) infection in humans. se is widely distributed in commercial chicken flocks and high levels of cecal carriage and shedding may lead to broiler meat contamination. in the present study, the preventive and eliminative effect of nonimmunized freeze-dried egg yolk powder (eyp) on se in broilers was investigated. in the prevention trial, reduced se counts were observed in liver (p < or = 0.05), cecal ... | 2006 | 17039835 |
| comparison of salmonella enterica serovar enteritidis levels in crops of fed or fasted infected hens. | long-term feed withdrawal has been shown to increase ileocecal intestinal colonization and fecal shedding of salmonella enterica serovar enteritidis in challenged hens. less information is available regarding effects of fasting on crop colonization. two trials were conducted to compare effects of 14-day feed withdrawal vs. full feed on crop colonization in hens challenged with salmonella enteritidis. the levels of salmonella enteritidis in the crops of fasted hens were significantly higher than ... | 2006 | 17039844 |
| contribution of target gene mutations and efflux to decreased susceptibility of salmonella enterica serovar typhimurium to fluoroquinolones and other antimicrobials. | the mechanisms involved in fluoroquinolone resistance in salmonella enterica include target alterations and overexpression of efflux pumps. the present study evaluated the role of known and putative multidrug resistance efflux pumps and mutations in topoisomerase genes among laboratory-selected and naturally occurring fluoroquinolone-resistant salmonella enterica serovar typhimurium strains. strains with ciprofloxacin mics of 0.25, 4, 32, and 256 microg/ml were derived in vitro using serovar typ ... | 2007 | 17043131 |
| effect of metc mutation on salmonella gallinarum virulence and invasiveness in 1-day-old white leghorn chickens. | salmonella enterica serotype gallinarum (s. gallinarum) is the causative agent of fowl typhoid (ft) in chickens. ft is a severe systemic disease of chickens causing heavy economic losses to the poultry industry through mortality, reduced egg production and culling of precious breeding stocks. in this study, a metc (encoding cystathionine beta lyase) mutant was produced from a virulent strain of s. gallinarum by mini-tn5 insertional inactivation. the mutant was significantly attenuated in virulen ... | 2007 | 17046177 |
| salmonella typhimurium infection triggers dendritic cells and macrophages to adopt distinct migration patterns in vivo. | the presence of an anti-bacterial t cell response and evidence of bacterial products in inflamed joints of reactive arthritis patients suggests an antigen transportation role in this disease for macrophages and dendritic cells. we have investigated the functional properties and in vivo migration of macrophages and dc after infection with salmonella enterica serovar typhimurium (s. typhimurium). bm-derived macrophages and dc displayed enhanced expression of costimulatory molecules (cd40 and cd86) ... | 2006 | 17048271 |
| intracellular demography and the dynamics of salmonella enterica infections. | an understanding of within-host dynamics of pathogen interactions with eukaryotic cells can shape the development of effective preventive measures and drug regimes. such investigations have been hampered by the difficulty of identifying and observing directly, within live tissues, the multiple key variables that underlay infection processes. fluorescence microscopy data on intracellular distributions of salmonella enterica serovar typhimurium (s. typhimurium) show that, while the number of infec ... | 2006 | 17048989 |
| genotypic diversity and antimicrobial resistance in asymptomatic salmonella enterica serotype typhimurium dt104. | the recent emergence of multidrug-resistant salmonella enterica subspecies enterica serotype typhimurium phage-type dt104 represents a challenge to health workers from both human and veterinary medicine. in an effort to develop effective control strategies, it is vital to characterize accurately the extent of genetic and phenotypic variation present in the pathogen population. while previous studies have focused on disease-associated populations, we report the genetic diversity and the diversity ... | 2007 | 17049315 |
| specific regions of genome plasticity and genetic diversity of the commensal escherichia coli a0 34/86. | escherichia coli a0 34/86 (o83:k24:h31) is a commensal strain that has been used for prophylactic and therapeutic colonization of the intestine of newborn infants. to identify traits specific for e. coli a0 34/86, we used a minimal tiling set of 148 bac clones of a0 34/86 genomic dna, to construct restriction-digested bac arrays. hybridization with genomic dna from four e. coli strains (cft073; o157:h7; k12 and nissle 1917) allowed selection of two bac clones that were sequenced to identify a0 3 ... | 2006 | 17049458 |
| involvement of complement pathways in patients with bacterial septicemia. | the complement system is a major humoral portion of the innate immune system, playing a significant role in host defence against microorganisms. the biological importance of this system is underlined by the fact that at least three different pathways for its activation exist, the classical, the mbl and the alternative pathway. to elucidate the involvement of the classical and/or the mbl pathway during bacterial septicemia, 32 patients with gram-positive and 30 patients with gram-negative bacteri ... | 2007 | 17049606 |
| characterization of a nonfimbrial mannose-sensitive hemagglutinin (msh) produced by salmonella enterica serovar enteritidis. | a nonfimbrial mannose-sensitive hemagglutinin (msh) with adhesive properties produced by salmonella enterica serovar enteritidis was characterized. the msh was characterized as glycoprotein and consisted of three noncovalently bound subunits of m(r) 28, 33 and 40 kda determined by sds-page. the hemagglutinin was heat-stable and resistant to alkaline (high) or acid (low) ph, however, it was inhibited by proteolytic enzymes, by edta and by sodium periodate. mouse antiserum raised against msh react ... | 2006 | 17049985 |