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"gently rough": the vaccine potential of a salmonella enterica regulatory lipopolysaccharide mutant.an alternative to multivalent vaccines could be to construct strains capable of conferring broad protection through shared antigens. down-regulation of immunodominant major antigens has been proposed to enhance the immunogenicity of conserved antigens.200818922095
a comparison of cecal colonization of salmonella enterica serotype typhimurium in white leghorn chicks and salmonella-resistant mice.salmonellosis is one of the most important bacterial food borne illnesses worldwide. a major source of infection for humans is consumption of chicken or egg products that have been contaminated with salmonella enterica serotype typhimurium, however our knowledge regarding colonization and persistence factors in the chicken is small.200818922185
early immune response following salmonella enterica subspecies enterica serovar typhimurium infection in porcine jejunal gut loops.salmonella enterica subspecies enterica serovar typhimurium, commonly called s. typhimurium, can cause intestinal infections in humans and various animal species such as swine. to analyze the host response to salmonella infection in the pig we used an in vivo gut loop model, which allows the analysis of multiple immune responses within the same animal. four jejunal gut-loops were each inoculated with 3 x 10(8) cfu of s. typhimurium in 3 one-month-old piglets and mrna expressions of various cytok ...200918922229
rapid multiplex pcr and real-time taqman pcr assays for detection of salmonella enterica and the highly virulent serovars choleraesuis and paratyphi c.salmonella enterica is a human pathogen with over 2,500 serovars characterized. s. enterica serovars choleraesuis and paratyphi c are two globally distributed serovars. we have developed a rapid molecular-typing method to detect serovars choleraesuis and paratyphi c in food samples by using a comparative-genomics approach to identify regions unique to each serovar from the sequenced genomes. a salmonella-specific primer pair based on oric was designed as an internal control to establish accuracy ...200818923008
lipopolysaccharide-induced immune responses in relation to the tlr4(asp299gly) gene polymorphism.altered microbial exposure is a possible explanation for the increase of allergies in the western world. however, genetic factors influence microbially induced immune responses. we have investigated the tlr4(asp299gly) gene polymorphism and its possible association with receptor expression of circulating peripheral blood monocytes and the in vitro cytokine responses and phosphorylation of intracellular signaling proteins in peripheral blood mononuclear cells (pbmc) stimulated with lipopolysaccha ...200818927069
the impact of temperature during the storage of table eggs on the viability of salmonella enterica serovars enteritidis and virchow in the eggs.salmonellosis is a foodborne infection of major economic importance. contamination of table eggs with salmonella, especially salmonella enterica serovar enteritidis, is a major health concern worldwide. recently, s. enterica serovar virchow has emerged as a major pathogen in israel, where it is among the 3 most prevalent serovars found in poultry and the second most prevalent serovar isolated from individuals with salmonellosis. although there is ample knowledge regarding the role of s. enterica ...200818931169
direct enhancement of the phagocytic and bactericidal capability of abdominal macrophage of chicks by beta-1,3-1,6-glucan.salmonella enterica serovar enteritidis is the major zoonotic and intracellular pathogen. different strategies have been developed to prevent the s. enteritidis infection. the beta-1,3-1,6-glucan of schizophyllum commune was used as an immunological booster to determine the minimal dietary level of beta-glucan that would restrict s. enteritidis infection through the effects of beta-glucan on the activity of macrophages and direct physical protection of the intestine. one-day-old male single comb ...200818931174
murein hydrolase activity in the surface layer of lactobacillus acidophilus atcc 4356.we describe a new enzymatic functionality for the surface layer (s-layer) of lactobacillus acidophilus atcc 4356, namely, an endopeptidase activity against the cell wall of salmonella enterica serovar newport, assayed via zymograms and identified by western blotting. based on amino acid sequence comparisons, the hydrolase activity was predicted to be located at the c terminus. subsequent cloning and expression of the c-terminal domain in bacillus subtilis resulted in the functional verification ...200818931300
abelson tyrosine kinase facilitates salmonella enterica serovar typhimurium entry into epithelial cells.the intracellular gram-negative bacterial pathogen salmonella enterica serovar typhimurium gains entry into nonphagocytic cells by manipulating the assembly of the host actin cytoskeleton. s. enterica serovar typhimurium entry requires a functional type iii secretion system, a conduit through which bacterial effector proteins are directly translocated into the host cytosol. we and others have previously reported the enhancement of tyrosine kinase activities during salmonella serovar typhimurium ...200918936177
rapid discrimination of salmonella isolates by single-strand conformation polymorphism analysis.a molecular typing technique was developed for the differentiation of salmonella isolates based on single-strand conformation polymorphism (sscp) analysis of amplicons generated by pcr. amplicons from parts of the fima (both the 5' and 3' ends), mdh, inva, and atpd genes were generated separately from a panel of salmonella strains representing salmonella bongori, and four subspecies and 17 serovars of salmonella enterica. these amplicons were subjected to sscp analysis for differentiation of the ...200818939738
environmental sampling to predict fecal prevalence of salmonella in an intensively monitored dairy herd.although dairy cattle are known reservoirs for salmonellae, cattle that are shedding this organism are often asymptomatic and difficult to identify. a dairy herd that was experiencing a sustained, subclinical outbreak of salmonella enterica subsp. enterica cerro was monitored for 2 years. fecal samples from the lactating cows were collected every 6 to 8 weeks and tested for the presence of salmonella. fecal prevalence of salmonella fluctuated throughout the observation period and ranged from 8 t ...200818939739
planktonic and biofilm community characterization and salmonella resistance of 14-day-old chicken cecal microflora-derived continuous-flow cultures.this study evaluated the composition of gastrointestinal bacterial communities in birds during an age in which their susceptibility to salmonella is highly diminished. one of the challenges to developing probiotics is to develop an efficacious culture of minimal diversity that includes bacteria that are vital contributors to protection from pathogens, but excludes unnecessary species. this study used in vitro continuous-flow culture techniques to test the ability of mixed bacterial cultures acqu ...200818939741
substituted 2-imino-5-arylidenethiazolidin-4-one inhibitors of bacterial type iii secretion.diverse species of pathogenic gram-negative bacteria use secretion systems to export a variety of protein toxins and virulence factors that help establish and maintain infection. disruption of such secretion systems is a potentially effective therapeutic strategy. we developed a high-throughput screen and identified a tris-aryl substituted 2-imino-5-arylidenethiazolidin-4-one, compound 1, as an inhibitor of the type iii secretion system. expansion of this chemotype enabled us to define the essen ...200818947223
examination of salmonella and escherichia coli translocation from hog manure to forage, soil, and cattle grazed on the hog manure-treated pasture.use of hog (sus scrofa) manure as a fertilizer is a practical solution for waste re-utilization, however, it may serve as a vehicle for environmental and domestic animal contamination. work was conducted to determine whether pathogens, naturally present in hog manure could be detected in cattle (bos taurus) grazed on the manure-treated pasture, and whether forage contamination occurred. during two 3 mo summer trials manure was applied to yield < or = 124 kg available n per hectare in a single sp ...200818948461
anti-flagellin antibody responses elicited in mice orally immunized with attenuated salmonella enterica serovar typhimurium vaccine strains.in the present study we investigated the flagellin-specific serum (igg) and fecal (iga) antibody responses elicited in balb/c mice immunized with isogenic mutant derivatives of the attenuated salmonella enterica serovar typhimurium (s. typhimurium) sl3261 strain expressing phase 1 (flici), phase 2 (fljb), or no endogenous flagellin. the data reported here indicate that mice orally immunized with recombinant s. typhimurium strains do not mount significant systemic or secreted antibody responses t ...200818949334
comparative analysis of protein profiles of wild virulent (e156) and aroa-htra double deletion mutant vaccine strain (s30) of salmonella enterica subsp. enterica serovar abortusequi under in vivo and in vitro growth conditions.in the present study, cell lysate and cell supernatant of the both strains i.e., virulent wild type (e156) and mutant (s30) vaccine strains of salmonella enterica subspecies enterica serovar abortusequi (s. abortusequi), grown under varied in vivo and in vitro conditions were subjected to sds page and western blotting (using rabbit hyperimmune serum). variation in growth conditions did not have any significant effect on expression of different proteins. sds page of e156 and s30 cell lysate (cl) ...200818949890
rapid classification and identification of salmonellae at the species and subspecies levels by whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry .variations in the mass spectral profiles of multiple housekeeping proteins of 126 strains representing salmonella enterica subsp. enterica (subspecies i), s. enterica subsp. salamae (subspecies ii), s. enterica subsp. arizonae (subspecies iiia), s. enterica subsp. diarizonae (subspecies iiib), s. enterica subsp. houtenae (subspecies iv), and s. enterica subsp. indica (subspecies vi), and salmonella bongori were analyzed to obtain a phylogenetic classification of salmonellae based on whole-cell m ...200818952875
structure and regulatory mechanism of aquifex aeolicus ntrc4: variability and evolution in bacterial transcriptional regulation.genetic changes lead gradually to altered protein function, making deduction of the molecular basis for activity from a sequence difficult. comparative studies provide insights into the functional consequences of specific changes. here we present structural and biochemical studies of ntrc4, a sigma-54 activator from aquifex aeolicus, and compare it with ntrc1 (a paralog) and ntrc (a homolog from salmonella enterica) to provide insight into how a substantial change in regulatory mechanism may hav ...200818955063
human polymorphonuclear neutrophil responses to burkholderia pseudomallei in healthy and diabetic subjects.the major predisposing factor for melioidosis is diabetes mellitus, but no immunological mechanisms have been investigated to explain this. in this study, polymorphonuclear neutrophil (pmn) responses to burkholderia pseudomallei, the causative agent of melioidosis, in healthy and diabetic thai subjects were determined by flow cytometry. the results showed that b. pseudomallei displayed reduced uptake by pmns compared to salmonella enterica serovar typhimurium and escherichia coli. additionally, ...200918955471
interleukin-23 orchestrates mucosal responses to salmonella enterica serotype typhimurium in the intestine.salmonella enterica serotype typhimurium causes an acute inflammatory reaction in the ceca of streptomycin-pretreated mice that involves t-cell-dependent induction of gamma interferon (ifn-gamma), interleukin-22 (il-22), and il-17 expression (genes ifn-gamma, il-22, and il-17, respectively). we investigated here the role of il-23 in initiating these inflammatory responses using the streptomycin-pretreated mouse model. compared to wild-type mice, the expression of il-17 was abrogated, il-22 expre ...200918955477
development of liposome immunoassay for salmonella spp. using immunomagnetic separation and immunoliposome.the ability to detect salmonella spp. is essential in the prevention of foodborne illness. this study examined a salmonella spp. detection method involving the application of immunomagnetic separation and immunoliposomes (ims/il) encapsulating sulforhodamine b (srb), a fluorescent dye. a quantitative assay was conducted by measuring the fluorescence intensity of srb that was produced from an immunomagnetic bead-salmonella spp.-immunoliposome complex. the results indicated detection limits of 2.7 ...200818955821
l-cysteine is required for induced antibiotic resistance in actively swarming salmonella enterica serovar typhimurium.swarm-cell differentiation in salmonella enterica serovar typhimurium (s. typhimurium) results in a biosynthetic mode of growth, despite growing on a rich medium, and cells that have elevated antibiotic resistance. these phenotypes are not a prerequisite for swarm motility. by blocking the switch to anabolic growth using amino acid auxotrophs and screening for the presence of elevated antibiotic resistance in the swarm state, we found that cysteine biosynthesis is crucial for complete swarm-cell ...200818957594
salmonella virulence factor spic is involved in expression of flagellin protein and mediates activation of the signal transduction pathways in macrophages.spic is a virulence factor encoded within salmonella pathogenicity island 2 (spi-2). we have previously reported that infection of macrophages with salmonella enterica serovar typhimurium results in the spi-2-dependent activation of the mitogen-activated protein kinase (mapk) signalling pathways, leading to the expression of suppressor of cytokine signalling (socs)-3, which is involved in the inhibition of cytokine signalling. here, we investigated the mechanism by which spic mediates the activa ...200818957602
salmonella from gopher tortoises (gopherus polyphemus) in south georgia.from 2002 to 2006, gopher tortoises (gopherus polyphemus) were collected at moody air force base, lowndes/lanier counties, georgia, usa, and opportunistically surveyed for the presence of salmonella species. four of 155 (2.6%) cloacal swabs collected from 80 tortoises were positive for the presence of salmonella enterica, and the following serovars were identified: give, hartford, javiana, and luciana. female tortoises (5%) were infected at a rate similar to male tortoises (5%). all isolates wer ...200818957656
simultaneous detection of escherichia coli o157:h7, salmonella spp. and listeria monocytogenes with an array-based immunosorbent assay using universal protein g-liposomal nanovesicles.a novel universal reagent for immunoassays, protein g-liposomal nanovesicles has been developed and successfully used in an immunomagnetic bead sandwich assay for the detection of escherichia coli o157:h7 [c.-s. chen, a.j. baeumner, r.a. durst, talanta 67 (2005) 205]. to demonstrate the universal capability of protein g-liposomal nanovesicles, this reagent was used to develop an array-based immunosorbent assay for the simultaneous detection of e. coli o157:h7, salmonella, and listeria monocytoge ...200618970559
ciprofloxacin-resistant salmonella enterica serovar typhi from kuwait with novel mutations in gyra and parc genes.blood isolates of salmonella enterica serovar typhi from two recently returned bangladeshi patients in kuwait were ciprofloxacin resistant, with ciprofloxacin mics of 12 mg/liter for both isolates. both isolates had three novel gyra mutations (55-leu-->trp, 87-asp-->ala, and 106-gln-->arg) and three novel parc mutations (84-glu-->lys, 106-trp-->gly, and 128-tyr-->asp).200918971360
maintenance of the salmonella-containing vacuole in the juxtanuclear area: a role for intermediate filaments.until recently, intermediate filaments (if) were thought to be only involved in resistance to physical stress and mechanical integrity of cells and tissues. recent data indicate that if play a much more important role in cellular physiology including organelle structure and positioning within the cell. here, we show that salmonella enterica serovar typhimurium (s. typhimurium) induces in epithelial cells and macrophages the formation of an aggresome-like structure with a dramatic remodelling of ...200818977288
surveillance of antibiotic resistance evolution and detection of class 1 and 2 integrons in human isolates of multi-resistant salmonella typhimurium obtained in uruguay between 1976 and 2000.to study the evolution of antibiotic resistance in isolates of salmonella enterica subspecies enterica serovar typhimurium (salmonella typhimurium) obtained in uruguay between the years 1976 and 2000, and to determine the incidence of class 1 and 2 integrons in the multi-resistant isolates.200918977678
mutagenesis of region 4 of sigma 28 from chlamydia trachomatis defines determinants for protein-protein and protein-dna interactions.transcription factor sigma(28) in chlamydia trachomatis (sigma(28)(ct)) plays a role in the regulation of genes that are important for late-stage morphological differentiation. in vitro mutational and genetic screening in salmonella enterica serovar typhimurium was performed in order to identify mutants with mutations in region 4 of sigma(28)(ct) that were defective in sigma(28)-specific transcription. specially, the previously undefined but important interactions between sigma(28)(ct) region 4 ...200918978051
biological and antibacterial activities of the natural herb houttuynia cordata water extract against the intracellular bacterial pathogen salmonella within the raw 264.7 macrophage.salmonellosis is a major bacterial zoonosis that causes a variety of disease syndromes, from self-limiting enteritis to fatal infection in animals and food-borne infection and typhoid fever in humans. recently, the emergence of multidrug-resistant strains of salmonella sp. has caused more serious problems in public health. the present study investigated the antibacterial effects of houttuynia cordata water extract (hcwe) against murine salmonellosis. in raw 264.7 cells, there was no detectable c ...200818981565
assessment of antibiotic resistance phenotype and integrons in salmonella enterica serovar typhimurium isolated from swine.salmonella enterica serovar typhimurium (s. typhimurium) isolated and identified from swine were subjected for the analysis of antibiotic resistance pattern and clinically important class 1 and 2 integrons. in addition, s. typhimurium isolates exhibiting ampicillin, chloramphenicol, streptomycin, sulfamethoxazole, tetracycline and florfenicol (acssutf) resistance pattern as described in most salmonella enterica serotype typhimurium definitive type 104 (dt104) were characterized by polymerase cha ...200818981675
effect of transcriptional activators rama and soxs on expression of multidrug efflux pumps acrab and acref in fluoroquinolone-resistant salmonella typhimurium.multidrug resistance (mdr) including fluoroquinolone resistance in salmonella typhimurium can result from overexpression of efflux pumps. we examined the mechanisms of fluoroquinolone resistance among in vitro-induced ciprofloxacin-resistant salmonella typhimurium mutants, ltl and lth, derived from laboratory strain lt2.200918984645
characterization of salmonella enterica isolates from infants and toddlers in wuhan, china.extended-spectrum cephalosporins and fluoroquinolones are important antimicrobials for treating invasive salmonellosis, and emerging resistance to these antimicrobials is of paramount concern. this study reports on the antimicrobial susceptibility and molecular characterization of salmonella enterica isolates recovered in 2006 from 0- to 3-year-old outpatients in china.200918984647
porcine in vitro and in vivo models to assess the virulence of salmonella enterica serovar typhimurium for pigs.salmonella typhimurium infections in pigs pose an important human health hazard. one promising control measure is the development of live attenuated vaccine strains using defined knockout mutants. preferably, screening of candidate knockout vaccine strains for attenuation should first be done in models allowing testing of a large number of strains. thereafter, a limited number of selected strains should be further characterized in an experimental infection model in pigs. the aim of the present s ...200918987064
update: recall of dry dog and cat food products associated with human salmonella schwarzengrund infections--united states, 2008.on may 16, 2008, cdc reported on a 2006-2007 multistate outbreak of infection with salmonella enterica serotype schwarzengrund that was associated with dry dog food. at the time of that report, a total of 70 cases had been reported from 19 states, with the last case identified on october 1, 2007. subsequently, an additional case was identified on december 29, 2007. epidemiologic and environmental investigations have suggested the source of the outbreak was dry pet food produced by one manufactur ...200818987615
proteolytic inactivation of tissue factor pathway inhibitor by bacterial omptins.the immune response to infection includes activation of the blood clotting system, leading to extravascular fibrin deposition to limit the spread of invasive microorganisms. some bacteria have evolved mechanisms to counteract this host response. pla, a member of the omptin family of gram-negative bacterial proteases, promotes the invasiveness of the plague bacterium, yersinia pestis, by activating plasminogen to plasmin to digest fibrin. we now show that the endogenous anticoagulant tissue facto ...200918988866
multiple abscesses caused by salmonella enterica and corynebacterium pseudotuberculosis in a dromedary camel.a rare case of arthritis, peri-arthiritis and pleurits associated with salmonella enterica and corynebacterium pseudotuberculosis infection in a dromedary camel is reported. articular infections caused by non-typhoidal salmonella have been exceptionally described in human medicine. to our knowledge, this would be the first description of articular infections associated with non-thyphoidal salmonella in other mammals than humans. possible pathogenesis of the infection is discussed.200918989744
mutants of the rna-processing enzyme rnase e reverse the extreme slow-growth phenotype caused by a mutant translation factor ef-tu.salmonella enterica with mutant ef-tu (gln125arg) has a low level of ef-tu, a reduced rate of protein synthesis and an extremely slow growth rate. eighty independent suppressor mutations were selected that restored normal growth. in some cases (n= 7) suppression was due to mutations in tufa but, surprisingly, in most cases (n= 73) to mutations in rne, the gene coding for rnase e. these rne mutations alone had only modest effects on growth rate. fifty different suppressor mutations were isolated ...200818990188
the role of interleukin-12 in the heavy metal-elicited immunomodulation: relevance of various evaluation methods.abstract:200818990205
gene expression profiling in chicken heterophils with salmonella enteritidis stimulation using a chicken 44 k agilent microarray.salmonella enterica serovar enteritidis (se) is one of the most common food-borne pathogens that cause human salmonellosis and usually results from the consumption of contaminated poultry products. the mechanism of se resistance in chickens remains largely unknown. previously, heterophils isolated from broilers with different genetic backgrounds (se-resistant [line a] and -susceptible [line b]) have been shown to be important in defending against se infections. to dissect the interplay between h ...200818990222
characterization of multidrug-resistant salmonella enterica serovar heidelberg isolated from humans and animals.salmonella enterica serovar heidelberg has been recognized as one of the most common serovar associated with foodborne infections in the united states. it is also frequently isolated from nonhuman sources and has increasingly shown resistance to various antimicrobial agents. the present study was undertaken to identify the predominant antimicrobial resistance phenotypes and genotypes of salmonella heidelberg (n = 95) isolates of human, swine, and turkey origin. antimicrobial susceptibility was d ...200818991546
fatal community-acquired pneumonia caused by legionella pneumophila and fluoroquinolone-resistant salmonella enterica serotype choleraesuis bacteraemia. 200918993035
correlating blood immune parameters and a cct7 genetic variant with the shedding of salmonella enterica serovar typhimurium in swine.the porcine response to salmonella infection is critical for control of salmonella fecal shedding and the establishment of salmonella carrier status. in this study, 40 crossbred pigs were intranasally inoculated with salmonella enterica serovar typhimurium (salmonella typhimurium) and monitored for salmonella fecal shedding and blood immune parameters at 2, 7, 14 and 20 days post-inoculation (dpi). using a multivariate permutation test, a positive correlation was observed between salmonella typh ...200918996651
occurrence and characterization of salmonella enterica subspecies enterica serovar 9,12:l,v:- strains from bulgaria, denmark, and the united states.in 2006, salmonella enterica serovar i 9,12:l,v:- emerged in bulgaria. the aim of this study was to characterize salmonella serovar i 9,12:l,v:- isolates from bulgaria, denmark, and the united states. we compared isolates of salmonella i 9,12:l,v:- and diphasic serovars with similar antigenic formulas by pulsed-field gel electrophoresis (pfge) and antimicrobial susceptibility. the phase 2 flagellin gene (fljb) was also sequenced for selected isolates. by pfge, the salmonella i 9,12:l,v:- isolate ...200918998175
excess of infections due to a multi-drug sensitive salmonella enterica serotype typhimurium in france in june 2008.an unusually high number of cases of salmonella typhimurium was reported in france in june 2008. in the course of epidemiological investigations 112 cases were ascertained, of whom 75 were interviewed. subtyping by pfge and mlva identified a strain named "majority profile". subtyping results were available for 45 interviewed cases, 30 of whom (majority below 15 years of age) were found to be infected with the majority profile strain. evidence suggested the occurrence of an outbreak due to a mono ...200819000564
outbreak of salmonella enterica serovar typhimurium in switzerland, may-june 2008, implications for production and control of meat preparations.an increased number of salmonella typhimurium cases were reported in switzerland between may and june 2008. investigations involved 72 cases. results of pfge typing identified several outbreak strains, the dominating one present in 43 of the 72 isolates. strains affecting one third of the cases were also found in animal samples, in particular pork. however, no specific food source could be identified. outbreaks described in this paper highlight the importance of food safety regulations such as t ...200819000565
the potassium transporter trk and external potassium modulate salmonella enterica protein secretion and virulence.potassium (k(+)) is the most abundant intracellular cation and is essential for many physiological functions of all living organisms; however, its role in the pathogenesis of human pathogens is not well understood. in this study, we characterized the functions of the bacterial trk k(+) transport system and external k(+) in the pathogenesis of salmonella enterica, a major food-borne bacterial pathogen. here we report that trk is important for salmonella to invade and grow inside epithelial cells. ...200919001074
characterization of plasmids harbouring qnrs1, qnrb2 and qnrb19 genes in salmonella.the aim of this study was to identify and characterize plasmids carrying qnrs1, qnrb2 and qnrb19 genes identified in salmonella strains from the netherlands. the identification of plasmids may help to follow the dissemination of these resistance genes in different countries and environments.200919001452
differential mrna expression of the avian-specific toll-like receptor 15 between heterophils from salmonella-susceptible and -resistant chickens.pattern recognition receptors (prrs) are essential for recognition of conserved molecular constituents found on infectious microbes. toll-like receptors (tlrs) are a critical component of the prr repertoire and are coupled to downstream production of cytokines, chemokines, and antimicrobial peptides by tlr adaptor proteins. our laboratory previously demonstrated a role for tlr function in the differential innate response of two lines of chickens to bacterial infections. the aim of the present st ...200919002681
functional analysis of a large non-conserved region of flgk (hap1) from rhodobacter sphaeroides.the single subpolar flagellum of rhodobacter sphaeroides shows an enlarged hook-filament junction. one of the two proteins that compose this section of the filament is hap1(rs) (flgk(rs)) it contains a central non-conserved region of 860 amino acids that makes this protein about three times larger than its homologue in salmonella enterica serovar typhimurium. we investigated the role of this central portion of the unusually large hap1 protein of r. sphaeroides by monitoring the effects of serial ...200919003427
modelling of the regulation of the hila promoter of type three secretion system of salmonella enterica serovar typhimurium.one of the most common modes of secretion of toxins in gram-negative bacteria is via the type three secretion system (ttss), which enables the toxins to be specifically exported into the host cell. the hila gene product is a key regulator of the expression of the ttss located on the pathogenicity island (spi-1) of salmonella enterica serovar typhimurium. it has been proposed earlier that the regulation of hila expression is via a complex feedforward loop involving the transactivators hild, hilc ...200719003447
salmonella induces death of cd8alpha(+) dendritic cells but not cd11c(int)cd11b(+) inflammatory cells in vivo via myd88 and tnfr1.dendritic cells (dcs), whose lifespan influences their ability to stimulate the immune system, are potent apcs that are critical for initiating immunity. here, we show that oral infection with salmonella enterica serovar typhimurium induces death of dcs in the gut-draining lymph nodes. although cd8alpha(+) dcs were sensitive to salmonella-induced death, cd8alpha(-) dcs and in particular recruited cd11c(int)cd11b(+) inflammatory cells, were resistant. infecting mice deficient for myd88 revealed t ...200919004989
influence of promoter, gene copy number, and preexisting immunity on humoral and cellular responses to a vectored antigen delivered by a salmonella enterica vaccine.attenuated salmonella strains are currently in production as vaccines for protection of animals against salmonellosis. such commercial strains offer the potential to deliver heterologous antigen to protect animals against other diseases. one vaccine strain, attenuated salmonella enterica serovar typhimurium (stm-1), was tested for the ability to deliver ovalbumin and to induce immune responses in mice. two vaccine trials were performed testing the influence of promoter choice, the location of th ...200919005022
controlled evaluation of bactec peds plus/f and bactec lytic/10 anaerobic/f media for isolation of salmonella enterica serovars typhi and paratyphi a from blood.we compared anaerobic lytic (al) and pediatric aerobic resin-containing (peds plus/f) blood culture media for the isolation of salmonella enterica serotype typhi or paratyphi a from children. the yields from al and peds plus/f media were the same with equal volumes of blood, but recovery was faster from al medium than peds plus/f medium (10.7 and 16.4 h, respectively) (p < 0.001).200919005140
the solution structure of the monomeric copper, zinc superoxide dismutase from salmonella enterica: structural insights to understand the evolution toward the dimeric structure.the structure of the sodcii-encoded monomeric cu, zn superoxide dismutase from salmonella enterica has been solved by nmr spectroscopy. this represents the first solution structure of a natural and fully active monomeric superoxide dismutase in solution, providing information useful for the interpretation of the evolutional development of these enzymes. the protein scaffold consists of the characteristic beta-barrel common to the whole enzyme family. the general shape of the protein is quite sim ...200819006322
risk factors for infection with pathogenic and antimicrobial-resistant fecal bacteria in northern elephant seals in california.the goal of this study was to identify potential environmental and demographic factors associated with campylobacter jejuni (c. jejuni), salmonella enterica (salmonella spp.), and antimicrobial-resistant escherichia coli (e. coli) infection in northern elephant seals stranded along the california coastline.200819006978
characterization of the myo-inositol utilization island of salmonella enterica serovar typhimurium.knockout mutation of stm4432 resulted in a growth-deficient phenotype of salmonella enterica serovar typhimurium in the presence of myo-inositol (mi) as the sole carbon source. stm4432 is part of a 22.6-kb genomic island which spans stm4417 to stm4436 (genomic island 4417/4436) and is responsible for mi degradation. genome comparison revealed the presence of this island in only six salmonella strains and a high variability of the iol gene organization in gram-negative bacteria. upon nonpolar del ...200919011032
outbreak of salmonella thompson infection in a swedish dairy herd.salmonella typhimurium was isolated from a faecal sample from a cow in a swedish dairy herd after calving. when investigations were undertaken in the herd, salmonella thompson was isolated from heifers on a separate pasture, and when these heifers were brought into the herd s thompson spread rapidly. control strategies managed to rid the herd of the s typhimurium infection and the prevalence of s thompson was at first substantially reduced. there was a rapid increase in its prevalence when the a ...200819011246
characterisation of antimicrobial resistance-associated integrons and mismatch repair gene mutations in salmonella serotypes.in this study, we examined the presence of integrons and salmonella genomic island 1 (sgi1) and assessed their contribution to antimicrobial resistance as well as determining the extent of the mutator phenotype in salmonella isolates. a total of 81 salmonella enterica serotype typhimurium isolates were examined for the presence of integrons and sgi1 and for hypermutators using polymerase chain reaction (pcr) and the mutator assay, respectively. an additional 336 salmonella isolates were also use ...200919013057
interleukin-15 and nk1.1+ cells provide innate protection against acute salmonella enterica serovar typhimurium infection in the gut and in systemic tissues.control of bacterial colonization at mucosal surfaces depends on rapid activation of the innate immune system. interleukin-15 (il-15) directs the development, maturation, and function of a population of cells positive for nk1.1, such as natural killer (nk) cells, which are critical components of the innate immune defense against several viral and bacterial pathogens. using il-15-deficient mice, in vivo depletion of nk1.1(+) cells from wild-type mice, and in vivo overexpression of il-15 from a re ...200919015253
truncated tni module adjacent to the complex integron of salmonella genomic island 1 in salmonella enterica serovar virchow.salmonella genomic island 1 was identified for the first time in salmonella enterica serovar virchow isolated from humans in taiwan. the complex class 1 integron conferring multidrug resistance was shown to be inserted within open reading frame (orf) s023 and contains for the first time a partial transpositional module. the 5-bp target duplication flanking the complex integron suggests that its insertion in orf s023 was by transposition.200919015337
a small-molecule screen identifies the antipsychotic drug pimozide as an inhibitor of listeria monocytogenes infection.we developed a screening procedure to identify small-molecule compounds that altered infection by listeria monocytogenes to gain insights into bacterial/host cellular processes required for intracellular pathogenesis. a small-molecule library of 480 compounds with known biological functions was screened, and 21 compounds that altered the l. monocytogenes infection of murine bone marrow-derived macrophages (bmm) were identified. the identified compounds affected various cellular functions, such a ...200919015342
variation in salmonella enterica serovar typhi inchi1 plasmids during the global spread of resistant typhoid fever.a global collection of plasmids of the inchi1 incompatibility group from salmonella enterica serovar typhi were analyzed by using a combination of dna sequencing, dna sequence analysis, pcr, and microarrays. the inchi1 resistance plasmids of serovar typhi display a backbone of conserved gene content and arrangement, within which are embedded preferred acquisition sites for horizontal dna transfer events. the variable regions appear to be preferred acquisition sites for dna, most likely through c ...200919015365
a reservoir of drug-resistant pathogenic bacteria in asymptomatic hosts.the population genetics of pathogenic bacteria has been intensively studied in order to understand the spread of disease and the evolution of virulence and drug resistance. however, much less attention has been paid to bacterial carriage populations, which inhabit hosts without producing disease. since new virulent strains that cause disease can be recruited from the carriage population of bacteria, our understanding of infectious disease is seriously incomplete without knowledge on the populati ...200819015729
nramp1 drives an accelerated inflammatory response during salmonella-induced colitis in mice.a recently developed model for enterocolitis in mice involves pre-treatment with the antibiotic streptomycin prior to infection with salmonella enterica serovar typhimurium (s. typhimurium). the contribution of nramp1/slc11a1 protein, a critical host defence mechanism against s. typhimurium, to the development of inflammation in this model has not been studied. here, we analysed the impact of nramp1 expression on the early development of colitis using isogenic nramp1(+/+) and nramp1(-/-) mice. w ...200919016783
protective immunity to systemic infection with attenuated salmonella enterica serovar enteritidis in the absence of il-12 is associated with il-23-dependent il-22, but not il-17.il-12 is essential for protective t cell-mediated immunity against salmonella infection. to characterize the role of the related cytokine il-23, wild-type (wt) c57bl/6 and p19(-/-) mice were infected systemically with an attenuated strain of salmonella enterica serovar enteritidis (s. enteritidis). il-23-deficient mice controlled infection with s. enteritidis similarly as wt mice. similar ifn-gamma production as compared with wt mice, but defective il-17a and il-22 production was found in the ab ...200819017979
polyhexamethylene guanidine hydrochloride-based disinfectant: a novel tool to fight meticillin-resistant staphylococcus aureus and nosocomial infections.polyhexamethylene guanidine hydrochloride (phmgh), an antimicrobial biocide of the guanidine family, was tested for efficacy against quality-control strains of staphylococcus aureus, pseudomonas aeruginosa, salmonella choleraesuis, meticillin-resistant s. aureus (mrsa) and escherichia coli. bactericidal activity against s. aureus, p. aeruginosa and salmonella choleraesuis was determined using the official methods of analysis of the association of official analytical chemists, with modifications ...200819018024
role of global regulator rma for multidrug efflux-mediated fluoroquinolone resistance in salmonella.the genetic basis for multidrug resistance (mdr) due to overexpression of mdr efflux pumps in escherichia coli usually includes alterations in genes encoding global regulators, like mara, soxs, and rob. in salmonella, in addition to these regulators, rma, for which no homolog exists in e. coli, seems to play a role in the regulation of efflux pumps. however, the exact mechanisms remain unclear. therefore, this study aimed at investigating the influence of the regulator rma on the expression of m ...200819018673
in ovo treatment with cpg oligodeoxynucleotides decreases colonization of salmonella enteriditis in broiler chickens.induction of the innate immune response in newly hatched chickens is important for limiting infections with bacteria, such as salmonella enterica serovar enteriditis (se). cpg oligodeoxynucleotides (cpg-odn) can stimulate the innate immune response of young chickens. therefore, we examined the effectiveness of cpg-odn administered in ovo on intestinal colonization by se and the ability to modulate the function of heterophils in young chickens. heterophils were isolated from 2-day-old chickens an ...200919019459
salmonella serovar specific upregulation of porcine defensins 1 and 2 in a jejunal epithelial cell line.defensins are important antimicrobial effector peptides of the innate immune system, which provides protection against bacterial infections in the intestine. salmonella choleraesuis and salmonella typhimurium are the most commonly isolated serovars in pig, but disease outcome is dependent on the salmonella serovar. these infections are a serious problem for the swine industry and are also posing a major threat to public health because of salmonella-related food-borne illnesses in human. to under ...200919019577
analysis of salmonella enterica with reduced susceptibility to the third-generation cephalosporin ceftriaxone isolated from u.s. cattle during 2000-2004.over the past decade enteric bacteria in europe, africa, and asia have become increasingly resistant to cephalosporin antimicrobial agents. this is largely due to the spread of genes encoding extended-spectrum beta-lactamase (esbl) enzymes that can inactivate many cephalosporins. recently, these resistance mechanisms have been identified in salmonella isolated from humans in the united states. due to the potential for transmission of resistant bacteria to humans via food animals, salmonella anim ...200819025468
mechanisms of rnd multidrug efflux pumps.rnd (resistance-nodulation-division) family transporters are widespread especially among gram-negative bacteria, and catalyze the active efflux of many antibiotics and chemotherapeutic agents. they have very large periplasmic domains, and form tripartite complexes with outer membrane channels and periplasmic adaptor proteins. acrab-tolc complex of escherichia coli, which pumps out a very wide range of drugs, has been studied most intensively. early studies showed that the transporter captures ev ...200919026770
effect of sample preparation and bacterial concentration on salmonella enterica detection in poultry meat using culture methods and pcr assaying of preenrichment broths.we evaluated the sensitivity of a pcr assay in the detection of salmonella enterica at the broth preenrichment step of poultry meat. a total of 162 retail poultry meat samples, which were prepared by manual massaging, stomacher or no homogenization were compared for salmonella recovery. using these homogenization methods, the pcr assay at the broth preenrichment step detected salmonella in, respectively, 48.9%, 62.2% and 50.0% of meat and giblet samples detected as salmonella-positive using the ...200919028296
interaction of enteric bacterial pathogens with murine embryonic stem cells.embryonic stem (es) cells are susceptible to genetic manipulation and retain the potential to differentiate into diverse cell types, which are factors that make them potentially attractive cells for studying host-pathogen interactions. murine es cells were found to be susceptible to invasion by salmonella enterica serovar typhimurium and shigella flexneri and to the formation of attaching and effacing lesions by enteropathogenic escherichia coli. s. enterica serovar typhimurium and s. flexneri c ...200919029302
qnrd, a novel gene conferring transferable quinolone resistance in salmonella enterica serovar kentucky and bovismorbificans strains of human origin.in a previous study, four salmonella isolates from humans in the henan province of china showed reduced susceptibility to ciprofloxacin (mic, 0.125 to 0.25 microg/ml) but were susceptible to nalidixic acid (mic, 4 to 8 microg/ml). all isolates were negative for known qnr genes (a, b, and s), aac(6')ib-cr, and mutations in gyra and parc. plasmid dna was extracted from all four isolates and transformed into escherichia coli tg1 and dh10b cells by electroporation, and transformants were selected on ...200919029321
csra and csrb are required for the post-transcriptional control of the virulence-associated effector protein avra of salmonella enterica.the virulence-associated effector protein avra of salmonella enterica is an ubiquitin-like acetyltransferase/cysteine protease, which interferes with the first line of immune response of the target organism. in contrast to translation of the avra protein in s. enterica strains, which takes place either constitutively (class 1 strains), or after acid induction (class 2 strains), or not at all (class 3 strains); the constitutive transcription of the respective avra genes occurs regardless of these ...200919042154
[antagonistic properties of enterococci isolated from gastrointestinal tract of long-livers].the strains with antagonistic activity against indicator strains pseudomonas aeruginosa, proteus vulgaris, staphylococcus aureus, staphylococcus epidermidis, escherichia coli, klebsiella pneumonia, salmonella enterica were revealed among 58 enterococcus strains isolated from gastrointestinal tract of long-livers. the influence of different components of mrs medium on the antagonistic effect was established. antagonistic activity remained on the medium without glucose in 36% of strains, on the me ...200819044009
risk associated with transportation and lairage on hide contamination with salmonella enterica in finished beef cattle at slaughter.transportation of cattle to the slaughter plant could influence hide contamination with salmonella enterica. fecal and hide samples were obtained from 40 lots of cattle at the feedlot and again at the slaughter plant. potential risk factors for hide contamination were evaluated. a multilevel poisson regression model was used to determine whether transportation and lairage were associated with hide contamination by salmonella. cattle with hide samples positive for salmonella at the feedlot had tw ...200819044266
differentiation of salmonella enterica serovars and strains in cultures and food using infrared spectroscopic and microspectroscopic techniques combined with soft independent modeling of class analogy pattern recognition analysis.detection of pathogenic microorganisms in food is often a tedious and time-consuming exercise. developing rapid and cost-effective techniques for identifying pathogens to subspecies is critical for tracking causes of foodborne disease outbreaks. the objective of this study was to develop a method for rapid identification and differentiation of salmonella serovars and strains within these serovars through isolation on hydrophobic grid membrane filters (hgmfs), examination by infrared (ir) spectro ...200819044269
inactivation of salmonella enterica serovar senftenberg 775w in liquid whole egg by ultrahigh pressure homogenization.two batches of samples of liquid whole egg were inoculated with a load of approximately 3 and 7 log cfu/ml, respectively, of salmonella enterica serovar senftenberg 775w and submitted to different ultrahigh pressure homogenization (uhph) treatments at 150, 200, and 250 mpa. the inlet temperature of the samples was 6 degrees c. counts of viable and injured salmonella cells were obtained 2 h after the uhph treatments and after 5, 10, 15, and 20 days of storage at 4 degrees c. the level of pressure ...200819044274
development of unique bacterial strains for use as positive controls in the food microbiology testing laboratory.nalidixic acid-resistant (nalr) mutants of salmonella enterica serovar berta and escherichia coli o157:h7 were derived from wild-type laboratory cultures to serve as distinguishable control strains for routine use in food microbiology testing programs. the prevalence of the nalr phenotype among different bacteria was verified using panels of related and unrelated strains with the ability to grow vigorously on plating media containing nalidixic acid, being restricted to the nalr mutants. the nalr ...200819044277
regulation of salmonella-induced membrane ruffling by sipa differs in strains lacking other effectors.the salmonella pathogenicity island 1 (spi-1) type three secretion system (ttss) is essential for salmonella invasion of host cells through its triggering of actin-dependent membrane ruffles. the spi-1 effectors sipa, sope, sope2 and sopb all have actin regulating activities and contribute to invasion. the precise role of actin regulation by sipa in salmonella invasion remains controversial since divergent data have been presented regarding the relationship between sipa and membrane ruffling. we ...200919046340
the malf p2 loop of the atp-binding cassette transporter malfgk2 from escherichia coli and salmonella enterica serovar typhimurium interacts with maltose binding protein (male) throughout the catalytic cycle.we have investigated the interaction of the uncommonly large periplasmic p2 loop of the malf subunit of the maltose atp-binding cassette transporter (malfgk(2)) from escherichia coli and salmonella enterica serovar typhimurium with maltose binding protein (male) by site-specific chemical cross-linking in the assembled transport complex. we focused on possible distance changes between two pairs of residues of the p2 loop and male during the transport cycle. the distance between malf(s205c) and ma ...200919047355
public health assessment of salmonella enterica serovar enteritidis inactivated-vaccine treatment in layer flocks.although there have been several reports on the efficacy assessment of a salmonella enterica serovar enteritidis vaccine against intestinal and parenchymatous organ diseases of laying hens, no public health risk characterization of its long-term effect on eggs has been reported. in this study, we attempted to assess the public health effect of an inactivated s. enterica serovar enteritidis vaccine against serovar enteritidis contamination of chicken eggs. we analyzed serovar enteritidis isolatio ...200919047380
burkholderia cenocepacia-induced delay of acidification and phagolysosomal fusion in cystic fibrosis transmembrane conductance regulator (cftr)-defective macrophages.the burkholderia cepacia complex (bcc) is a group of opportunistic bacteria chronically infecting the airways of patients with cystic fibrosis (cf). several laboratories have shown that bcc members, in particular b. cenocepacia, survive within a membrane-bound vacuole inside phagocytic and epithelial cells. we have previously demonstrated that intracellular b. cenocepacia causes a delay in phagosomal maturation, as revealed by impaired acidification and slow accumulation of the late phagolysosom ...200819047750
salmonella translocates across an in vitro m cell model independently of spi-1 and spi-2.we have used an in vitro model of intestinal m cells to examine the mechanisms by which salmonella enterica translocates across these specialized cells, which constitute a primary site of infection of the mammalian host. s. enterica can invade cultured cells by deploying a type iii secretion system (ttss) encoded within salmonella pathogenicity island 1 (spi-1) to translocate effector proteins into the host cell cytoplasm that trigger cellular responses, including prominent cytoskeletal rearrang ...200819047755
contamination of chicken meat with salmonella enterica serovar haardt with nalidixic acid resistance and reduced fluoroquinolone susceptibility.salmonella contamination in chicken meat was studied with 100 chicken meat samples purchased from 55 shops located in various regions. a total of 21 isolates of salmonella enterica were isolated from 21 chicken meat samples from four shops located at open markets, whereas there were none from supermarkets with well-equipped cold systems. among these, 18 isolates were identified as salmonella enterica serotype haardt (s. haardt) and three isolates were s. enterica serotype muenchen. when the mini ...200819047832
tlr9-independent effects of inhibitory oligonucleotides on macrophage responses to s. typhimurium.detection of bacterial cpg-containing dna (cpg dna) by innate immune cells is dependent on toll-like receptor 9 (tlr9). here we show that the expression of tlr9 mrna was induced in mouse bone marrow-derived macrophages (bmms) upon infection with the facultative gram-negative intracellular bacterium salmonella enterica serovar typhimurium (s. typhimurium). treatment of bmm with the inhibitory oligonucleotide (odn) 2114, an antagonist of tlr9 signalling, enhanced intracellular s. typhimurium numbe ...200919048019
dexamethasone modulates salmonella enterica serovar typhimurium infection in vivo independently of the glucocorticoid-inducible protein annexin-a1.salmonella enterica serovar typhimurium (s. typhimurium) infection causes an inflammatory response through activation of toll-like receptor 4 by lipopolysaccharide. dexamethasone, a glucocorticoid analogue, suppresses inflammatory responses by many mechanisms including inhibition of the lipopolysaccharide-induced production of proinflammatory mediators. there is little information on the effect of glucocorticoids on murine salmonellosis. in this study, we treated susceptible balb/c mice by subcu ...200819049646
differential expression from two iron-responsive promoters in salmonella enterica serovar typhimurium reveals the presence of iron in macrophage-phagosomes.the metal status of macrophage-phagosomes during salmonella infection is largely unknown. in this study, we have precisely calibrated the metal-specificities of two metal-responsive promoters, p(irobcde) and p(sodb), from salmonella enterica serovar typhimurium and used these to directly monitor iron-levels in salmonella-containing macrophage-phagosomes. expression from the p(irobcde) promoter is highly elevated in metal-depleted media but low in media supplemented with iron or cobalt, and to a ...200919049822
selection, characterization, and application of dna aptamers for the capture and detection of salmonella enterica serovars.sensitive and specific pre-analytical sample processing methods are needed to enhance our ability to detect and quantify food borne pathogens from complex food and environmental samples. in this study, dna aptamers were selected and evaluated for the capture and detection of salmonella enterica serovar. typhimurium. a total of 66 candidate sequences were enriched against s. typhimurium outer membrane proteins (omps) with counter-selection against escherichia coli omps and lipopolysaccharides (lp ...200919049862
differentially evolved genes of salmonella pathogenicity islands: insights into the mechanism of host specificity in salmonella.the species salmonella enterica (s. enterica) includes many serovars that cause disease in avian and mammalian hosts. these serovars differ greatly in their host range and their degree of host adaptation. the host specificity of s. enterica serovars appears to be a complex phenomenon governed by multiple factors acting at different stages of the infection process, which makes identification of the cause/s of host specificity solely by experimental methods difficult.200819050757
detection of salmonella enterica serotype typhimurium dt104 in mozambique.the spread of salmonella enterica serotype typhimurium definitive phage type dt104 in sub-saharan africa is a public health concern. we obtained two isolates of s. typhimurium dt104 from blood cultures of infants with malaria in mozambique. both isolates contained salmonella genomic island 1a and had the same pulsed-field gel electrophoresis pulsenet pattern (stymxb.0005). results showed the need for continuous surveillance of salmonella spp. serotypes circulating in this area.200819052305
aroa and arod mutations influence biofilm formation in salmonella enteritidis.aro mutants of salmonella enterica are frequently used as live vaccines for the oral vaccination of domestic animals. interestingly, besides their auxotrophy, they appear to be of reduced resistance to the components of innate immune response due to a defect in outer membrane and/or cell wall integrity. because different extracellular structures associated with the cell wall or outer membrane are involved in biofilm formation, we were interested in the ability of aroa and arod mutants of s. ente ...200919054077
the survival of salmonella enterica serovar typhimurium dt104 and total viable counts on beef surfaces at different relative humidities and temperatures.the aim of this study was to investigate changes in salmonella and total viable count (tvc) survival on beef carcass surfaces stored for 72 h under different combinations of relative humidity (i.e. rh 75% or 96%) and temperature (5 degrees c or 10 degrees c).200919054240
typhoid fever in southern taiwan: a medical center experience.typhoid fever is caused by salmonella enterica serotype typhi (5. typhi). growing communication between taiwan and neighboring regions in recent years could be an important source of typhoid fever. the aim of this study was to analyze the clinical characteristics of typhoid fever treated at a medical center in southern taiwan.200819054916
detection of qnr genes in salmonella isolated from humans in denmark. 200919056747
probiotic bacteria are antagonistic to salmonella enterica and campylobacter jejuni and influence host lymphocyte responses in human microbiota-associated immunodeficient and immunocompetent mice.a defined human microbiota-associated (hma) mouse model in balb/c and immunodeficient tgepsilon26 mice was used to assess the ability of probiotic lactobacilli and bifidobacteria to enhance colonization resistance to gastrointestinal (gi) tract pathogens. probiotic bacteria (1x10(8) colony forming unit (cfu)/ml) successfully excluded campylobacter jejuni from both strains of mice 7 days after challenge. the probiotic bacteria also reduced the number of salmonella in the large intestines of both ...200919065588
construction of phage mutants.recent studies have established that the most abundant life form, that of phages, has had major influence on the biosphere, bacterial evolution, bacterial genome, and lateral gene transmission. importantly the phages have served and continue to serve as valuable model systems. such studies have led to a renewed interest and activity in the study of phages and their genomes. in order to determine the details of the involvement of phages in these important processes and activities, it is critical ...200919066824
generalized transduction.transduction is the process in which bacterial dna is transferred from one bacterial cell to another by means of a phage particle. there are two types of transduction, generalized transduction and specialized transduction. in this chapter two of the best-studied systems - escherichia coli-phage p1, and salmonella enterica-phage p22 - are discussed from theoretical and practical perspectives.200919066827
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