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salmonella enterica serovar typhimurium invades fibroblasts by multiple routes differing from the entry into epithelial cells.fibroblasts are ubiquitous cells essential to tissue homeostasis. despite their nonphagocytic nature, fibroblasts restrain replication of intracellular bacterial pathogens such as salmonella enterica serovar typhimurium. the extent to which the entry route of the pathogen determines this intracellular response is unknown. here, we analyzed s. typhimurium invasion in fibroblasts obtained from diverse origins, including primary cultures and stable nontransformed cell lines derived from normal tiss ...201020368348
rck of salmonella enterica, subspecies enterica serovar enteritidis, mediates zipper-like internalization.salmonella can invade non-phagocytic cells through its type iii secretion system (t3ss-1), which induces a trigger entry process. this study showed that salmonella enterica, subspecies enterica serovar enteritidis can also invade cells via the rck outer membrane protein. rck was necessary and sufficient to enable non-invasive e. coli and rck-coated beads to adhere to and invade different cells. internalization analysis of latex beads coated with different rck peptides showed that the peptide con ...201020368731
antibacterial effect of the bioactive compound beauvericin produced by fusarium proliferatum on solid medium of wheat.to obtain the bioactive compound beauvericin (bea), fusarium proliferatum cect 20569 was grown on a solid medium of wheat, utilizing the technique of the solid state fermentation (ssf), being this mycotoxin purified by high performance liquid chromatography (hplc) with a reverse phase semi-preparative column using as the mobile phase acetonitrile/water in gradient condition. the purity of the bea was verified by analytical hplc and liquid chromatography tandem mass spectrometry (lc/ms-ms). the p ...201020371252
proteins from latex of calotropis procera prevent septic shock due to lethal infection by salmonella enterica serovar typhimurium.the latex of calotropis procera has been used in traditional medicine to treat different inflammatory diseases. the anti-inflammatory activity of latex proteins (lp) has been well documented using different inflammatory models. in this work the anti-inflammatory protein fraction was evaluated in a true inflammatory process by inducing a lethal experimental infection in the murine model caused by salmonella enterica subsp. enterica serovar typhimurium.201020371281
oral vaccination with attenuated salmonella enterica strains encoding t-cell epitopes from tumor antigen ny-eso-1 induces specific cytotoxic t-lymphocyte responses.bacterial fimbriae can accept foreign peptides and display them on the cell surface. a highly efficient gene replacement method was used to generate peptide vaccines based on salmonella enterica serovar typhimurium sl3261. the t-cell epitopes (ny-eso-1 p157-165 and p157-167) from ny-eso-1, which is a promising target antigen in patients for the specific immune recognition of cancer, were incorporated into the gene encoding agfa (the major subunit protein of thin aggregative fimbriae of salmonell ...201020375244
safety and immunogenicity of salmonella typhimurium expressing c-terminal truncated human il-2 in a murine model.salmonella enterica serovar typhimurium preferentially colonizes tumors in vivo and has proven to be an effective biologic vector. the attenuated s. enterica typhimurium strain chi4550 was engineered to express truncated human interleukin-2 and renamed salpil2. previously, we observed that a single oral administration of salpil2 reduced tumor number and volume, while significantly increasing local and systemic natural killer (nk) cell populations in an experimental metastasis model. here we repo ...201020376175
functional dissection of translocon proteins of the salmonella pathogenicity island 2-encoded type iii secretion system.type iii secretion systems (t3ss) are essential virulence factors of most gram-negative bacterial pathogens. t3ss deliver effector proteins directly into the cytoplasm of eukaryotic target cells and for this function, the insertion of a subset of t3ss proteins into the target cell membrane is important. these proteins form hetero-oligomeric pores acting as translocon for the delivery of effector proteins. salmonella enterica is a facultative intracellular pathogen that uses the salmonella pathog ...201020377892
use of ionic liquid-based extraction for recovery of salmonella typhimurium and listeria monocytogenes from food matrices.methods for rapid separation (<5 h) and concentration of bacteria based on solubilization of complex food matrices have been developed recently to facilitate rapid molecular detection methods. however, a major disadvantage of these protocols is the resulting lack of viability of the microorganisms under study due to extensive use of chemicals and enzymes, which can inhibit subsequent quantitative microbiological analyses. in this study, a new class of organic salts, ionic liquids, were used for ...201020377956
rapid detection and identification of bacterial pathogens by using an atp bioluminescence immunoassay.rapid identification of viable bacterial contaminants in food products is important because of their potential to cause disease. this study examined a method for microbial detection by using a combined atp bioluminescence immunoassay. escherichia coli o157:h7 and salmonella enterica serovar typhimurium were selected as target organisms because of their implication in foodborne illness. various matrices containing the target cells were examined, including ground beef homogenate, apple juice, milk ...201020377965
development of a novel multiplex pcr for the detection and differentiation of salmonella enterica serovars typhi and paratyphi a.in this study, we developed a multiplex polymerase chain reaction (mpcr) assay for pan-salmonella detection as well as for specific detection of serovars typhi and paratyphi a. the assay detects members of the salmonella genus by amplifying the outer membrane protein c (ompc). the presence of either salmonella serovar typhi or paratyphi a is indicated by amplification of the putative regulatory protein gene sty4220, which is common to both serovars. further differentiation of the serovars was ac ...201020381608
thiamine biosynthesis can be used to dissect metabolic integration.the emergence of systems biology has re-emphasized the advantages of understanding biological processes with a global perspective. one biological process amenable to global approaches is microbial metabolism. this review describes a model system that contributes to the goals of systems biology by experimentally defining metabolic integration found in a bacterial cell and thus providing data needed for implementation and interpretation of systems approaches. we have taken a largely unbiased in vi ...201020382023
study of matrix additives for sensitive analysis of lipid a by matrix-assisted laser desorption ionization mass spectrometry.matrix-assisted laser desorption ionization-time of flight mass spectrometry (maldi-tof ms) has been widely used for structural characterization of bacterial endotoxins (lipid a). however, the mass spectrometric behavior of the lipid a molecule is highly dependent on the matrix. furthermore, this dependence is strongly linked to phosphorylation patterns. using lipid a from escherichia coli o116 as a model system, we have investigated the effects of different matrices and comatrix compounds on th ...201020382818
anti-infective mechanisms induced by a probiotic lactobacillus strain against salmonella enterica serovar typhimurium infection.the prevention of pathogen infections is one of the most extensively studied effects of probiotics. l. casei crl 431 is a probiotic bacterium and its effects on the gut immune cells have been extensively studied. the aim of the present study was to determine, using a mouse model, the preventive and therapeutic effect of l. casei crl 431 to achieve protection against salmonella enteritidis serovar typhimurium infection. in both previous and continuous (previous and post-infection) probiotic admin ...201020193971
salmonella enterica serovar typhimurium-induced placental inflammation and not bacterial burden correlates with pathology and fatal maternal disease.food-borne infections caused by salmonella enterica species are increasing globally, and pregnancy poses a high risk. pregnant mice rapidly succumb to s. enterica serovar typhimurium infection. to determine the mechanisms involved, we addressed the role of inflammation and bacterial burden in causing placental and systemic disease. in vitro, choriocarcinoma cells were a highly conducive niche for intracellular s. typhimurium proliferation. while infection of mice with s. typhimurium wild-type (w ...201020194592
chronic murine typhoid fever is a natural model of secondary hemophagocytic lymphohistiocytosis.hemophagocytic lymphohistiocytosis (hlh) is a hyper-inflammatory clinical syndrome associated with neoplastic disorders especially lymphoma, autoimmune conditions, and infectious agents including bacteria, viruses, protozoa and fungi. in both human and veterinary medicine, hemophagocytic histiocytic disorders are clinically important and frequently fatal. hlh in humans can be a primary (familial, autosomal recessive) or secondary (acquired) condition, with both types generally precipitated by an ...201020195482
structure of the o-polysaccharide of salmonella enterica o41.an o-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide of salmonella enterica o41, and the following structure of the o-unit was determined by chemical analyses along with 1d and 2d (1)h and (13)c nmr spectroscopy: -->2)-beta-d-manp-(1-->4)-alpha-d-glcp-(1-->3)-alpha-l-quipnac-(1-->3)-alpha-d-glcpnac-(1--> where quinac stands for 2-acetamido-2,6-dideoxyglucose. the structure established is in agreement with the o-antigen gene cluster of s. enterica o41 and tentative ...201020199769
salmonella pathogenicity island 1 differentially modulates bacterial entry to dendritic and non-phagocytic cells.salmonella enterica serovar typhimurium can enter non-phagocytic cells, such as intestinal epithelial cells, by virtue of a type three secretion system (ttss) encoded in the salmonella pathogenicity island 1 (spi-1), which translocates bacterial effector molecules into the host cell. salmonella can also be taken up by dendritic cells (dcs). although the role of spi-1 in non-phagocytic cell invasion is well established, its contribution to invasion of phagocytic cells has not been evaluated. here ...201020201987
probiotics down-regulate genes in salmonella enterica serovar typhimurium pathogenicity islands 1 and 2.salmonella typhimurium pathogenesis relies mainly on the expression of genes of two pathogenicity islands, salmonella pathogenicity islands 1 and 2 (spi1 and spi2). each island has its own pattern of expression and regulation. success in suppression of the responsible key activator of each island would be an effective way of controlling salmonella, especially with the emerging problem of antibiotic-resistant strains. probiotics have been shown to inhibit several foodborne pathogens, and their mo ...201020202329
lessons learned from the management of a national outbreak of salmonella ohio linked to pork meat processing and distribution.during the summer of 2005, an increase in reports of human cases of salmonella enterica serovar ohio infection was observed in belgium. during 11 weeks, between 1 july and 13 september, 60 cases of laboratory-confirmed salmonella ohio infection were reported to the national reference centre for salmonella, with a peak onset of symptoms in the third week of july. all clinical isolates caused self-limiting gastroenteritis; both genders (32 males and 28 females) and all age groups (three children < ...201020202340
synergistic effects of ethanol and uv radiation to reduce levels of selected foodborne pathogenic bacteria.the purpose of this study was to determine whether combined treatments would produce synergistic disinfection effects on food products during food processing compared with single treatments. we investigated the bactericidal effects of a commercial chemical disinfectant (ethanol) and of uv radiation on bacillus cereus f4810/72, cronobacter sakazakii kctc 2949, staphylococcus aureus atcc 35556, escherichia coli atcc 10536, and salmonella enterica typhimurium no/na in vitro. various concentrations ...201020202345
salmonella isolated from the feces of migrating cranes at the izumi plain (2002-2008): serotype, antibiotic sensitivity and pfge type.from november 2002 to february 2008, 2,251 crane feces were collected at the izumi plain in kagoshima prefecture. salmonella enterica was isolated from 359 feces (15.9%), of which 332 (92.5%) were salmonella typhimurium (st), 9 were s. hvittingfoss/ii, 4 were s. abaetetuba, 3 were s. enteritidis, 2 were s. konstanz, 1 was s. pakistan and 8 were untyped isolates, respectively. against 12 antimicrobial agents, no resistant strains were found in 154 isolates examined, but one was found to be resist ...201020203434
synergistic antimicrobial effect of nisin and p-cymene on salmonella enterica serovar typhi in vitro and on ready-to-eat food.foods contaminated with salmonella enterica serovar typhi are a major cause of typhoid fever, leading to public health problems and economic losses worldwide. nisin and rho-cymene were tested in this study for their antimicrobial activity against s. typhi at 4 degrees c and 37 degrees c. nisin and rho-cymene, when used separately, did not inhibit the bacterium at either temperature. a synergistic antimicrobial effect between both compounds was observed when they were used simultaneously. this sy ...201020208367
the c terminus of sipc binds and bundles f-actin to promote salmonella invasion.salmonella enterica serovar typhimurium invade non-phagocytic cells by injecting bacterial effector proteins to exploit the host actin cytoskeleton network. sipc is such a salmonella effector known to nucleate actin, bundle f-actin, and translocate type iii effectors. the molecular mechanism of how sipc bundles f-actin and sipc domains responsible for these activities are not well characterized. we successfully separated these activities through a series of genetic deletion/insertions in sipc. w ...201020212042
the tandem inversion duplication in salmonella enterica: selection drives unstable precursors to final mutation types.during growth under selection, mutant types appear that are rare in unselected populations. stress-induced mechanisms may cause these structures or selection may favor a series of standard events that modify common preexisting structures. one such mutation is the short junction (sj) duplication with long repeats separated by short sequence elements: ab*(cd)*(cd)*e (* = a few bases). another mutation type, described here, is the tandem inversion duplication (tid), where two copies of a parent seq ...201020215473
differential inhibition of human immunodeficiency virus type 1 in peripheral blood mononuclear cells and tzm-bl cells by endotoxin-mediated chemokine and gamma interferon production.bacterial lipopolysaccharide (endotoxin) is a frequent contaminant of biological specimens and is also known to be a potent inducer of beta-chemokines and other soluble factors that inhibit hiv-1 infection in vitro. though lipopolysaccharide (lps) has been shown to stimulate the production of soluble hiv-1 inhibitors in cultures of monocyte-derived macrophages, the ability of lps to induce similar inhibitors in other cell types is poorly characterized. here we show that lps exhibits potent anti- ...201020218881
ppgpp-mediated stationary phase induction of the genes encoded by horizontally acquired pathogenicity islands and cob/pdu locus in salmonella enterica serovar typhimurium.salmonella enterica is highly diverse in terms of genome structure, which is at least partly due to the horizontal transfer of genetic elements from various sources. in this study, we examined the expression profiles of such genes in salmonella pathogenicity islands (spis) and the cob/pdu locus, horizontally acquired large dna segments, during growth under standard growth conditions. transcripts from exponentially growing and early stationary phase salmonellae were compared using various methods ...201020221735
influence of 5 major salmonella pathogenicity islands on nk cell depletion in mice infected with salmonella enterica serovar enteritidis.in this study we were interested in the colonisation and early immune response of balb/c mice to infection with salmonella enteritidis and isogenic pathogenicity island free mutants.201020226037
differences in attachment of salmonella enterica serovars to cabbage and lettuce leaves.this study investigated the ability of five salmonella enterica serovars to attach to and colonize intact and cut lettuce (iceberg, romaine) and cabbage surfaces. biofilm formation and attachment of salmonella serovars to intact and cut leaves were determined. populations of loosely and strongly attached salmonella were obtained to calculate the attachment strength (s(r)). biofilm formation, as determined by microtiter plate assay, varied with strain and growth medium used. salmonella tennessee ...201020226552
inactivation of salmonella enteritidis strains by combination of high hydrostatic pressure and nisin.the effects of high hydrostatic pressure (hhp) and nisin treatment alone and in combination on cellular components and viability of two salmonella enterica subsp. enterica serovar enteritidis (s. enteritidis) strains were evaluated by differential scanning calorimetry (dsc) and plate counting in order to evaluate the relative resistance and optimize the treatment conditions. s. enteritidis fda and osu 799 strains were subjected to hhp (0.1-550 mpa for 10 min at 25 degrees c) alone and in combina ...201020226554
in vitro antagonistic activities of animal intestinal strains against swine-associated pathogens.a wide range of enteropathogens cause costly diarrhoeal diseases in fattening piglets and account for food-related infections in humans. the objective of this study was to screen beneficial bacterial strains from the gastrointestinal tract of various animal sources for antagonistic activity against diverse pathogens associated with hazardous pig production times. using agar spot assays, 15 well-characterized strains belonging to lactobacillus, enterococcus, bifidobacterium and bacillus were stud ...201020226602
the salmonella enterica serovar typhimurium qseb response regulator negatively regulates bacterial motility and swine colonization in the absence of the qsec sensor kinase.salmonella enterica serovar typhimurium (s. typhimurium) responds to the catecholamine, norepinephrine by increasing bacterial growth and enhancing motility. in this study, iron with or without the siderophore, ferrioxamine e also enhanced bacterial motility. iron-enhanced motility was growth-rate dependent, while norepinephrine-enhanced motility was growth-rate independent. the outer membrane catecholate receptors, iron, fepa and cira (required for norepinephrine-enhanced growth) were not requi ...201020227482
kinetics of growth and inactivation of salmonella enterica serotype typhimurium dt104 in pasteurised liquid egg products.the potential impact of post-pasteurisation contamination of liquid egg products with the multi-antibiotic resistant pathogen salmonella enterica serotype typhimurium definitive type 104 (dt104) was assessed by determining the viability of this bacterium in whole egg, albumen and 10% w/w sugared and salted yolk incubated at 4-42 degrees c. results indicated that populations of s. typhimurium dt104 were slowly inactivated in all four products when stored at 4 degrees c. however, based on the typi ...201020227605
cryptdin-2: a novel therapeutic agent for experimental salmonella typhimurium infection.salmonella infections represent a major health hazard and have been responsible for a number of epidemics. in view of the emergence of multidrug-resistant salmonella strains, there is a need for therapeutic alternatives. the purpose of this study was to evaluate the therapeutic potential of cryptdin-2 (a paneth cell antimicrobial peptide) against salmonella infection.201020228082
accuracy and sensitivity of commercial pcr-based methods for detection of salmonella enterica in feed.the present study compared the performance of commercial pcr-based salmonella enterica detection methods (bax system q7, the iq-check salmonella ii kit, and the taqman salmonella enterica detection kit) with culture-based methods (modified semisolid rappaport-vassiliadis [msrv] and nmkl71) in spiked and naturally contaminated samples of feed mill scrapings (fms), palm kernel meal (pkm), pelleted feed (pf), rape seed meal (rsm), soybean meal (sm), and wheat grain (wg). when results from the vario ...201020228106
imaging type-iii secretion reveals dynamics and spatial segregation of salmonella effectors.the type-iii secretion system (t3ss) enables gram-negative bacteria to inject effector proteins into eukaryotic host cells. upon entry, t3ss effectors work cooperatively to reprogram host cells, enabling bacterial survival. progress in understanding when and where effectors localize in host cells has been hindered by a dearth of tools to study these proteins in the native cellular environment. we report a method to label and track t3ss effectors during infection using a split-gfp system. we demo ...201020228815
the multi-copper-ion oxidase cueo of salmonella enterica serovar typhimurium is required for systemic virulence.salmonella enterica serovar typhimurium possesses a multi-copper-ion oxidase (multicopper oxidase), cueo (also known as cuid), a periplasmic enzyme known to be required for resistance to copper ions. cueo from s. typhimurium was expressed as a recombinant protein in escherichia coli, and the purified protein exhibited a high cuprous oxidase activity. we have characterized an s. typhimurium cueo mutant and confirmed that it is more sensitive to copper ions. using a murine model of infection, it w ...201020231415
identification by pcr of non-typhoidal salmonella enterica serovars associated with invasive infections among febrile patients in mali.in sub-saharan africa, non-typhoidal salmonella (nts) are emerging as a prominent cause of invasive disease (bacteremia and focal infections such as meningitis) in infants and young children. importantly, including data from mali, three serovars, salmonella enterica serovar typhimurium, salmonella enteritidis and salmonella dublin, account for the majority of non-typhoidal salmonella isolated from these patients.201020231882
periplasmic peptidyl-prolyl isomerases sura and fkpa play an important role in the starvation-stress response (ssr) of salmonella enterica serovar typhimurium.carbon-energy source (c)-starved cells of salmonella enterica serovar typhimurium (s. typhimurium) are remarkably more resistant to stress than actively growing ones. carbon-starved s. typhimurium is capable of withstanding extended periods of starvation and assault from a number of different stresses that rapidly kill growing cells. these unique properties of the c-starved cell are the direct result of a series of genetic and physiological adaptations referred to as the starvation-stress respon ...201020232248
structural and functional characterization of three dsba paralogues from salmonella enterica serovar typhimurium.in prototypic escherichia coli k-12 the introduction of disulfide bonds into folding proteins is mediated by the dsb family of enzymes, primarily through the actions of the highly oxidizing protein ecdsba. homologues of the dsb catalysts are found in most bacteria. interestingly, pathogens have developed distinct dsb machineries that play a pivotal role in the biogenesis of virulence factors, hence contributing to their pathogenicity. salmonella enterica serovar (sv.) typhimurium encodes an exte ...201020233716
intrafamilial transmission of extended-spectrum-beta-lactamase-producing escherichia coli and salmonella enterica babelsberg among the families of internationally adopted children.international adoption from developing countries has become an increasing phenomenon in recent years. given the high prevalence of multidrug-resistant (mdr) bacteria in these countries, the adopted children represent a group at risk for both carriage and infection with mdr bacteria. the dynamics of intrafamilial transmission of mdr bacteria after adoption was studied in a prospective study from january 2002 to january 2005.201020233775
mechanisms and physiological effects of protamine resistance in salmonella enterica serovar typhimurium lt2.protamines are cationic peptides that exert antimicrobial activity. we have examined the evolution of bacterial resistance to protamine sulphate and the resulting effects on fitness and physiology, with the objective of increasing knowledge about mechanisms of bacterial resistance to antimicrobial peptides.201020233778
salicylate reduces the antimicrobial activity of ciprofloxacin against extracellular salmonella enterica serovar typhimurium, but not against salmonella in macrophages.salicylate, a potent inducer of the mara activator in salmonella enterica, is the principal metabolite of aspirin, which is often consumed for medicinal and cosmetic uses. our research was aimed at testing if salicylate activates the mar regulon in macrophage-associated salmonella (intracellular bacteria), and investigating its effects on bacterial susceptibility to ciprofloxacin extracellularly and intracellularly.201020237076
attenuated salmonella choleraesuis-mediated rnai targeted to conserved regions against foot-and-mouth disease virus in guinea pigs and swine.in this study, specific sequences within three genes (3d, vp4 and 2b) of the foot-and-mouth disease virus (fmdv) genome were determined to be effective rnai targets. these sequences are highly conserved among different serotype viruses based on sequence analysis. small interfering rna (sirna)-expressing plasmids (p3d-nt19, p3d-nt56, pvp4-nt19, pvp4-nt65 and p2b-nt25) were constructed to express sirna targeting 3d, vp4 and 2b, respectively. the antiviral potential of these sirna for various fmdv ...201020167192
cell biology. rise of the rival. 201020167774
[antimicrobial susceptibility and resistance genes among salmonella enterica serovar weltevreden isolates from humans, farm animals, and the environment in okinawa prefecture between 1992 and 2007].between 1992 and 2007, a total of 86 isolates of salmonella enterica weltevreden were obtained from clinical human samples (n = 41), 45 farm animals and their environment on 20 farms, including poultry (n = 25), beef cattle (n = 5), swine (n = 5), dairy cattle (n = 3), mice (n = 2), pony (n = 1), fly (n = 1) and feed samples (n = 3), in okinawa prefecture, japan. only seven isolates (8.1%) of the isolates were resistance to one or more antimicrobial agents tested; six streptomycin (7.0%), six ox ...201020170010
[a 14-year-old healthy boy with splenic abscess due to salmonella enterica serovar senftenberg].salmonella enterica serovar senftenberg may very rarely cause splenic abscess, which can be diagnosed using gallium scintigraphy and drained. a 14-year-old boy admitted for stomachache, diarrhea and fever and diagnosed from his symptoms as having enteritis did not respond when treated with fosfomycin, meropenem, and clindamycin. a low-density splenic area seen in abdominal computed tomography on admission did not show contrast medium enhancement. gallium scintigraphy on hospital day 10, however, ...201020170018
immunogenic properties of a recombinant fusion protein containing the c-terminal 19 kda of plasmodium falciparum merozoite surface protein-1 and the innate immunity agonist flic flagellin of salmonella typhimurium.in a recent study, we demonstrated the immunogenic properties of a new malaria vaccine polypeptide based on a 19 kda c-terminal fragment of the merozoite surface protein-1 (msp1(19)) from plasmodium vivax and an innate immunity agonist, the salmonella enterica serovar typhimurium flagellin (flic). herein, we tested whether the same strategy, based on the msp1(19) component of the deadly malaria parasite plasmodium falciparum, could also generate a fusion polypeptide with enhanced immunogenicity. ...201020170765
spontaneous excision of the salmonella enterica serovar enteritidis-specific defective prophage-like element phise14.salmonella enterica serovar enteritidis has emerged as a major health problem worldwide in the last few decades. dna loci unique to s. enteritidis can provide markers for detection of this pathogen and may reveal pathogenic mechanisms restricted to this serovar. an in silico comparison of 16 salmonella genomic sequences revealed the presence of an approximately 12.5-kb genomic island (gei) specific to the sequenced s. enteritidis strain nctc13349. the gei is inserted at the 5' end of gene ydao ( ...201020172996
autonomous growth of isolated single listeria monocytogenes and salmonella enterica serovar typhimurium cells in the absence of growth factors and intercellular contact.the aim of this study was to observe growth of isolated single bacterial cells in the absence of growth factors and intercellular contact. in order to exclude stochastic uncertainties induced by dilution series, a new micromanipulation method was developed to ensure explicit results under visual control. this was performed with particular care for production of single prokaryotic cells and subsequent investigation of their autonomous growth. over 450 single isolated listeria monocytogenes and sa ...201020173058
an antimicrobial peptide that targets dna repair intermediates in vitro inhibits salmonella growth within murine macrophages.the hexapeptide wrwycr was previously identified on the basis of its ability to inhibit bacteriophage lambda integrase-mediated recombination by trapping and preventing resolution of the holliday junction intermediate. this peptide inhibits several unrelated dna repair enzymes that bind to and process holliday junctions and branched dna substrates. wrwycr and its d stereoisomer, wrwycr, are bactericidal against both gram-positive and gram-negative bacteria, causing the accumulation of dna breaks ...201020176906
gallstones play a significant role in salmonella spp. gallbladder colonization and carriage.salmonella enterica serovar typhi can colonize the gallbladder and persist in an asymptomatic carrier state that is frequently associated with the presence of gallstones. we have shown that salmonellae form bile-mediated biofilms on human gallstones and cholesterol-coated surfaces in vitro. here, we test the hypothesis that biofilms on cholesterol gallbladder stones facilitate typhoid carriage in mice and men. naturally resistant (nramp1(+/+)) mice fed a lithogenic diet developed cholesterol gal ...201020176950
amplification of the gene for isoleucyl-trna synthetase facilitates adaptation to the fitness cost of mupirocin resistance in salmonella enterica.mutations that cause resistance to antibiotics in bacteria often reduce growth rate by impairing some essential cellular function. this growth impairment is expected to counterselect resistant organisms from natural populations following discontinuation of antibiotic therapy. unfortunately (for disease control) bacteria adapt and improve their growth rate, often without losing antibiotic resistance. this adaptation process was studied in mupirocin-resistant (mup(r)) strains of salmonella enteric ...201020176977
proton-conductivity assay of plugged and unplugged mota/b proton channel by cytoplasmic phluorin expressed in salmonella.mota and motb form the proton-channel complex of the proton-driven bacterial flagellar motor. a plug segment of escherichia coli motb suppresses proton leakage through the mota/b complex when it is not assembled into the motor. using a ratiometric ph indicator protein, phluorin, we show that the proton-conductivity of a salmonella mota/b complex not incorporated into the motor is two orders of magnitude lower than that of a complex that is incorporated and activated. this leakage is, however, si ...201020178785
pulsed-field gel electrophoresis diversity of human and bovine clinical salmonella isolates.pulsed-field gel electrophoresis (pfge) characterization of 335 temporally and spatially matched clinical, bovine, and human salmonella enterica subsp. enterica isolates revealed 167 xbai pfge patterns. these isolates were previously classified into 51 serotypes and 73 sequence types, as determined by multilocus sequence typing. discriminatory power of pfge (simpson's index, d = 0.991) was considerably higher than that of multilocus sequence typing (d = 0.920) or serotyping (d = 0.913). although ...201020180633
sialic acid is required for nonspecific adherence of salmonella enterica ssp. enterica serovar typhi on caco-2 cells.to initiate infection, bacteria must adhere to and colonize host tissues. specific and nonspecific mechanisms participate in the adherence process. salmonella enterica ssp. enterica serovar typhi (s. typhi) must first adhere to the intestinal epithelium to invade and disseminate throughout the host. in this study, the role of colonic epithelial cell surface sialic acid in the adherence of s. typhi was defined. neuraminidase treatment of colonic caco-2 cells removed 27-58% of surface sialic acid. ...201020180850
relatedness of the o-polysaccharide structures of escherichia coli o123 and salmonella enterica o58, both containing 4,6-dideoxy-4-{n-[(s)-3-hydroxybutanoyl]-d-alanyl}amino-d-glucose; revision of the e. coli o123 o-polysaccharide structure.o-polysaccharides were isolated by mild acid degradation of the lipopolysaccharides of escherichia coli o123 and salmonella enterica o58 and studied by chemical methods and 2d (1)h and (13)c nmr spectroscopy, including experiments in a h(2)o/d(2)o mixture, which enabled observation of correlations for nitrogen-linked protons. the following structure of the o-polysaccharide of e. coli o123 was established: -->3)-beta-d-quip4nalahb-(1-->6)-alpha-d-glcpnac-(1-->3)-alpha-l-quipnac-(1-->3)-alpha-d-gl ...201020181329
salmonella pathogenicity island 1 (spi-1) type iii secretion of sopd involves n- and c-terminal signals and direct binding to the invc atpase.salmonella enterica serovar typhimurium (s. typhimurium) is an important pathogen and a causative agent of gastroenteritis. during infection, s. typhimurium assembles molecular-needle complexes termed type iii secretion (t3s) systems to translocate effector proteins from the bacterial cytoplasm directly into the host cell. the t3s signals that direct the secretion of effectors still remain enigmatic. sopd is a key t3s effector contributing to the systemic virulence of s. typhimurium and the deve ...201020185511
salmonella enterica serotype cerro among dairy cattle in new york: an emerging pathogen?the focus of this study was salmonella enterica serotype cerro, a potentially emerging pathogen of cattle. our objectives were to document the within-herd prevalence of salmonella cerro among a sample of new york dairy herds, to describe the antimicrobial resistance patterns and pulsed-field gel electrophoresis types of the isolates, and to elucidate the status of this serotype as a bovine pathogen. data were collected prospectively from dairy herds throughout new york that had at least 150 lact ...201020187753
sub-iliac lymph nodes at slaughter lack ability to predict salmonella enterica prevalence for swine farms.the aim of this study was to assess the value of deep systemic sub-iliac lymph nodes collected at slaughter as predictors of salmonella prevalence in live hogs. an observational study was conducted on 24 farms from september 2006 to february 2009. at least one cohort of market-weight pigs was visited for each farm. within each cohort, 30 farm fecal samples on farm and 30 sub-iliac lymph nodes from matched pigs at slaughter were collected. samples were cultured for salmonella enterica and serotyp ...201020187754
drug resistance patterns in salmonella enterica subspecies enterica serotype typhi strains isolated over a period of two decades, with special reference to ciprofloxacin and ceftriaxone.fluoroquinolone-resistant salmonella enterica subspecies enterica serotype typhi are being increasingly reported from the asian subcontinent. this has been hypothesised to be due to a double mutation in the gyra gene. a total of 113 s. typhi strains isolated during 1987-2006 in a tertiary-level hospital of north india were monitored for their antibiotic susceptibility by the disk diffusion and minimum inhibitory concentration (mic) methods. the study period was arbitrarily divided into four equa ...201020188522
listeria and salmonella bacterial vectors of tumor-associated antigens for cancer immunotherapy.this review covers the use of the facultative intracellular bacteria, listeriamonocytogenes and salmonella enterica serovar typhimurium as delivery systems for tumor-associated antigens in tumor immunotherapy. because of their ability to infect and survive in antigen presenting cells, these bacteria have been harnessed to deliver tumor antigens to the immune system both as bacterially expressed proteins and encoded on eukaryotic plasmids. they do this in the context of strong innate immunity, wh ...201020299242
the high-adhesive properties of the fimh adhesin of salmonella enterica serovar enteritidis are determined by a single f118s substitution.the binding properties of low- and high-adhesive forms of fimh adhesins from salmonella enterica serovars enteritidis and typhimurium (s. enteritidis and s. typhimurium) were studied using chimeric proteins containing an additional peptide that represents an n-terminal extension of the fimf protein. this modification, by taking advantage of a donor strand exchange mechanism, closes the hydrophobic groove in the fimbrial domain of the fimh adhesin. such self-complemented adhesins (scfimh) did not ...201020299404
inhibition of the ptdins(5) kinase pikfyve disrupts intracellular replication of salmonella.3-phosphorylated phosphoinositides (3-ptdins) orchestrate endocytic trafficking pathways exploited by intracellular pathogens such as salmonella to gain entry into the cell. to infect the host, salmonellae subvert its normal macropinocytic activity, manipulating the process to generate an intracellular replicative niche. disruption of the ptdins(5) kinase, pikfyve, be it by interfering mutant, sirna-mediated knockdown or pharmacological means, inhibits the intracellular replication of salmonella ...201020300065
identification of the regulatory logic controlling salmonella pathoadaptation by the ssra-ssrb two-component system.sequence data from the past decade has laid bare the significance of horizontal gene transfer in creating genetic diversity in the bacterial world. regulatory evolution, in which non-coding dna is mutated to create new regulatory nodes, also contributes to this diversity to allow niche adaptation and the evolution of pathogenesis. to survive in the host environment, salmonella enterica uses a type iii secretion system and effector proteins, which are activated by the ssra-ssrb two-component syst ...201020300643
expression of the avian-specific toll-like receptor 15 in chicken heterophils is mediated by gram-negative and gram-positive bacteria, but not tlr agonists.toll-like receptors (tlrs) are a critical component of the innate immune response of mammalian and avian species. while most mammalian tlrs have been well characterized, the chicken-specific tlr15 has not been extensively studied. we recently demonstrated that tlr15 is differentially expressed between salmonella-susceptible-and-resistant chickens, indicating a potential role in the innate immune response to infection with salmonella. the aim of the present study was to gain better insight into t ...201020303182
evaluation of suspension array analysis for detection of egg yolk antibodies against salmonella enteritidis.salmonella enterica serovar enteritidis (se) is an important source of food-related diarrhoea in humans, and table eggs are considered the primordial source of contamination of the human food chain. using eggs collected at egg-packing stations as samples could be a convenient strategy to detect colonization of layer flocks. the aim of this study was to evaluate egg yolk anti-salmonella antibody detection using suspension array analysis. an egg yolk panel from contact-infected and non-colonized l ...201020303192
characterisation of multidrug-resistant salmonella typhimurium 4,[5],12:i:- dt193 strains carrying a novel genomic island adjacent to the thrw trna locus.in 2006, monophasic, multidrug-resistant salmonella enterica spp. enterica serovar 4,[5],12:i:- strains appeared as a novel serotype in germany, associated with large diffuse outbreaks and increased need for hospitalisation. the emerging 4,[5],12:i:- strains isolated from patients in germany belong mainly to phage type dt193 according to the anderson phage typing scheme for s. typhimurium (stm) and exhibit at least a tetra-drug resistance. the strains have been shown to harbour stm-specific gifs ...201020303825
natural and synthetic compounds such as trimethoprim behave as inhibitors of efflux in gram-negative bacteria.we hypothesized that small heterocyclic or nitrogen-containing compounds could act as rnd efflux pump inhibitors (epis). to ascertain possible epis, we sought to identify compounds that synergized with substrates of rnd efflux pumps for wild-type bacteria and those that overexpress an efflux pump, but had no synergistic activity against strains in which a gene encoding a component of the acrab-tolc efflux pump had been inactivated.201020304975
thiol peroxidase protects salmonella enterica from hydrogen peroxide stress in vitro and facilitates intracellular growth.at present, salmonella is considered to express two peroxiredoxin-type peroxidases, tsaa and ahpc. here we describe an additional peroxiredoxin, tpx, in salmonella enterica and show that a single tpx mutant is susceptible to exogenous hydrogen peroxide (h(2)o(2)), that it has a reduced capacity to degrade h(2)o(2) compared to the ahpcf and tsaa mutants, and that its growth is affected in activated macrophages. these results suggest that tpx contributes significantly to the sophisticated defense ...201020304995
effect of bovine lactoferrin in salmonella ser. typhimurium infection in mice.lactoferrin (lf) has in vitro antimicrobial activity against gram-negative bacteria. salmonella enterica subsp. enterica serovar typhimurium causes systemic infection and acute diarrhea in humans, mainly in children younger than 2 years of age. the aim of the study was to determine the in vivo effect of bovine lf in salmonella ser. typhimurium infection in mice. 58 balb/c mice were employed. two hours before the infection with 300 microl of 10(7) cfu of salmonella ser. typhimurium, 29 mice recei ...201020306285
fine-tuning synthesis of yersinia pestis lcrv from runaway-like replication balanced-lethal plasmid in a salmonella enterica serovar typhimurium vaccine induces protection against a lethal y. pestis challenge in mice.a balanced-lethal plasmid expression system that switches from low-copy-number to runaway-like high-copy-number replication (pya4534) was constructed for the regulated delayed in vivo synthesis of heterologous antigens by vaccine strains. this is an antibiotic resistance-free maintenance system containing the asda gene (essential for peptidoglycan synthesis) as a selectable marker to complement the lethal chromosomal deltaasda allele in live recombinant attenuated salmonella vaccines (rasvs) suc ...201020308296
short n-terminal sequences package proteins into bacterial microcompartments.hundreds of bacterial species produce proteinaceous microcompartments (mcps) that act as simple organelles by confining the enzymes of metabolic pathways that have toxic or volatile intermediates. a fundamental unanswered question about bacterial mcps is how enzymes are packaged within the protein shell that forms their outer surface. here, we report that a short n-terminal peptide is necessary and sufficient for packaging enzymes into the lumen of an mcp involved in b(12)-dependent 1,2-propaned ...201020308536
the salmonella type iii secretion effector, salmonella leucine-rich repeat protein (slrp), targets the human chaperone erdj3.effectors of the type iii secretion systems (t3ss) are key elements in the interaction between many gram-negative pathogens and their hosts. slrp is an effector that is translocated into the eukaryotic host cell through the two virulence-associated t3ss of salmonella enterica. we found previously that this effector is an e3 ubiquitin ligase for mammalian thioredoxin. here, we identified erdj3, an endoplasmic reticulum lumenal chaperone of the hsp40/dnaj family, as a new target for slrp. experime ...201020335166
detection and control of a nosocomial outbreak caused by salmonella newport at a large animal hospital.nosocomial salmonellosis is often assumed to occur because infection control and surveillance practices are inadequate, but published evidence is lacking to support the related contention that rigorous application of these practices can impact the severity of outbreaks.201020337913
reactogenicity and immunogenicity of live attenuated salmonella enterica serovar paratyphi a enteric fever vaccine candidates.eight salmonella enterica serovar paratyphi a strains were screened as candidates to create a live attenuated paratyphoid vaccine. based on biochemical and phenotypic criteria, four strains, rks2900, mgn9772, mgn9773 and mgn9779, were selected as progenitors for the construction of deltaphopq mutant derivatives. all strains were evaluated in vitro for auxotrophic phenotypes and sensitivity to deoxycholate and polymyxin b. all deltaphopq mutants were more sensitive to deoxycholate and polymyxin b ...201020338215
determination of water quality variables, endotoxin concentration, and enterobacteriaceae concentration and identification in southern high plains dairy lagoons.the objectives of this study were to determine the concentration of endotoxin, determine 20 water quality variables, and identify and enumerate fungal and bacterial pathogens from united states southern high plains dairy lagoons and control lakes during summer and winter. water samples were collected in triplicate from the north, south, east, and west quadrants of each body of water. the mean (+/- sem) winter dairy lagoon endotoxin concentration was significantly higher (9,678+/-1,834 ng/ml) tha ...201020338428
genetic analysis of multidrug-resistant salmonella enterica serovars stanley and typhimurium from cattle.during 2005-2008, a longitudinal study was conducted in southern japan to detect and characterize multidrug-resistant salmonella enterica serovars recovered from cattle diagnostic specimens. determination of antimicrobial resistance phenotypes and genotypes, identification of salmonella genomic island 1 (sgi1), detection of virulence genes, plasmid analysis, conjugal transfer experiments, and sequencing of class 1 integrons were conducted. multidrug-resistant salmonella detected were serovars st ...201020338699
[construction and characterization of recombinant salmonella enterica serovar choleraesuis vaccine strain expressing heterologous antigen of pasteurella multocida toxin].this study was aimed to construct and characterize salmonella vaccine strain c500 expressing the recombinant pasteurella multocida toxin (pmt) antigen by the asd+ balanced-lethal host-vector system.201020344946
reversible n epsilon-lysine acetylation regulates the activity of acyl-coa synthetases involved in anaerobic benzoate catabolism in rhodopseudomonas palustris.rhodopseudomonas palustris grows photoheterotrophically on aromatic compounds available in aquatic environments rich in plant-derived lignin. benzoate degradation is regulated at the transcriptional level in r. palustris in response to anoxia and the presence of benzoate and/or benzoyl-coa (bz-coa). here, we report evidence that anaerobic benzoate catabolism in this bacterium is also regulated at the post-translational level. in this pathway, benzoate is activated to bz-coa by the amp-forming bz ...201020345662
a soluble form of the pilus protein fima targets the vdac-hexokinase complex at mitochondria to suppress host cell apoptosis.inhibition of apoptotic response of host cells during an early phase of infection is a strategy used by many enteroinvasive bacterial pathogens to enhance their survival. here, we report the identification of a soluble form of the pilus protein fima from the culture supernatants of e. coli k1, salmonella, and shigella that can potently inhibit bax-mediated release of cytochrome c from isolated mitochondria. similar to the infected cells, hct116 cells stably expressing fima display a delay in the ...201020347420
16s rrna methyltransferase rmtc in salmonella enterica serovar virchow.we screened salmonella and escherichia coli isolates, collected 2004-2008 in the united kingdom, for 16s rrna methyltransferases. rmtc was identified in s. enterica serovar virchow isolates from clinical samples and food. all isolates were clonally related and bore the rmtc gene on the bacterial chromosome. surveillance for and research on these resistance determinants are essential.201020350396
ramr mutations in clinical isolates of klebsiella pneumoniae with reduced susceptibility to tigecycline.five klebsiella pneumoniae isolates with reduced susceptibility to tigecycline (mic, 2 microg/ml) were analyzed. a gene homologous to ramr of salmonella enterica was identified in klebsiella pneumoniae. sequencing of ramr in the nonsusceptible klebsiella strains revealed deletions, insertions, and point mutations. transformation of mutants with wild-type ramr genes, but not with mutant ramr genes, restored susceptibility to tigecycline and repressed overexpression of rama and acrb. thus, this st ...201020350947
the role of the flik molecular ruler in hook-length control in salmonella enterica.a molecular ruler, flik, controls the length of the flagellar hook. flik measures hook length and catalyses the secretion-substrate specificity switch from rod-hook substrate specificity to late substrate secretion, which includes the filament subunits. here, we show normal hook-length control and filament assembly in the complete absence of the c-ring thus refuting the previous 'cup' model for hook-length control. mutants of c-ring components, which are reported to produce short hooks, show a r ...201020132451
carvacrol and cinnamaldehyde inactivate antibiotic-resistant salmonella enterica in buffer and on celery and oysters.the emergence of antibiotic-resistant salmonella is of concern to food processors. the objective of this research was to identify antimicrobial activities of cinnamaldehyde and carvacrol against antibiotic-resistant salmonella enterica in phosphate-buffered saline (pbs) and on celery and oysters. twenty-three isolates were screened for resistance to seven antibiotics. two resistant and two susceptible strains were chosen for the study. s. enterica cultures (10(5) cfu/ml) were added to different ...201020132667
use of electron beam radiation for the reduction of salmonella enterica serovars typhimurium and tennessee in peanut butter.peanut butter and peanut paste products were implicated as the vehicle of contamination in an outbreak of salmonella typhimurium, which began in september 2008, and in the november 2006 outbreak of salmonella tennessee. therefore, this study evaluated the effectiveness of electron beam (e-beam) radiation for the reduction of salmonella serovars tennessee (atcc 10722) and typhimurium (atcc 14028) in creamy peanut butter. each strain was studied independently. peanut butter samples were inoculated ...201020132682
dynamics of intracellular bacterial replication at the single cell level.several important pathogens cause disease by surviving and replicating within host cells. bacterial proliferation is the product of both replication and killing undergone by the population. however, these processes are difficult to distinguish, and are usually assessed together by determination of net bacterial load. in addition, measurement of net load does not reveal heterogeneity within pathogen populations. this is particularly important in persistent infections in which slow or nongrowing b ...201020133586
an oligonucleotide microarray to characterize multidrug resistant plasmids.many of the enterobacteriaceae carry multiple drug resistance (mdr) genes on large plasmids of replicon type inc a/c and inc h1. it is important to understand the transmission of these mdr plasmids because the genes they carry can affect the outcome of antimicrobial therapy. the aim of this study was to design a microarray with oligonucleotide probes for every gene in the six inc a/c and one inc h1 plasmids of interest while representing all redundant sequences only once. the microarray is print ...201020138094
genetic modification of the salmonella membrane physical state alters the pattern of heat shock response.it is now recognized that membranes are not simple physical barriers but represent a complex and dynamic environment that affects membrane protein structures and their functions. recent data emphasize the role of membranes in sensing temperature changes, and it has been shown that the physical state of the plasma membrane influences the expression of a variety of genes such as heat shock genes. it has been widely shown that minor alterations in lipid membranes are critically involved in the conv ...201020139186
relevance of dna alkylation damage repair systems in salmonella enterica virulence.systematic inactivation of pathways involved in dna alkylation damage repair demonstrated that inactivation of the ada, ogt, tag, uvra, and mfd genes is required to detect a salmonella enterica virulence decrease. furthermore, the fitness of s. enterica, defective in these genes, is lowered only when the bacterium is orally, but not intraperitoneally, inoculated.201020139190
changes in membrane fluid state and heat shock response cause attenuation of virulence.so far attenuation of pathogens has been mainly obtained by chemical or heat treatment of microbial pathogens. recently, live attenuated strains have been produced by genetic modification. we have previously demonstrated that in several prokaryotes as well as in yeasts and mammalian cells the heat shock response is controlled by the membrane physical state (mps). we have also shown that in salmonella enterica serovar typhimurium lt2 (salmonella typhimurium) overexpression of a delta(12)-desatura ...201020139193
synthesis of ag/cnt hybrid nanoparticles and fabrication of their nylon-6 polymer nanocomposite fibers for antimicrobial applications.ag-coated cnts hybrid nanoparticles (ag/cnts) were prepared by ultrasonic irradiation of dimethylformamide (dmf) and silver (i) acetate precursors in the presence of cnts. the morphology of ag/cnts was characterized using x-ray diffraction and transmission electron microscopy (tem) techniques. the nylon-6 powder and 1 wt% ag/cnts mixture was dispersed uniformly using a noncontact spinning technique. the dried mixture was melted in a single screw extrusion machine and then extruded through an ori ...201020139493
structural and biochemical characterization of srca, a multi-cargo type iii secretion chaperone in salmonella required for pathogenic association with a host.many gram-negative bacteria colonize and exploit host niches using a protein apparatus called a type iii secretion system (t3ss) that translocates bacterial effector proteins into host cells where their functions are essential for pathogenesis. a suite of t3ss-associated chaperone proteins bind cargo in the bacterial cytosol, establishing protein interaction networks needed for effector translocation into host cells. in salmonella enterica serovar typhimurium, a t3ss encoded in a large genomic i ...201020140193
chicken meat is an infection source of salmonella serovar infantis for humans in japan.the study sets out to either confirm or refute a recent study's findings that chicken meat is an unlikely source of salmonella enterica subspecies enterica serovar infantis (salmonella infantis) in humans in the kyushu-okinawa region, japan.201020141347
antibacterial activity of carvacrol and 2-nitro-1-propanol against single and mixed populations of foodborne pathogenic bacteria in corn flour dough.cereal doughs are an important part of human diet, but at the same time can act as vehicles for the transmission of human pathogenic bacteria. in the present study, four pathogenic or toxinogenic bacteria (escherichia coli o157:h7, salmonella enterica serovar enteritidis, bacillus cereus and staphylococcus aureus) were inoculated in a dough made from corn flour in combination with the single antimicrobial compounds carvacrol and 2-nitro-1-propanol (2npoh). survival of single and mixed population ...201020141946
so similar, yet so different: uncovering distinctive features in the genomes of salmonella enterica serovars typhimurium and typhi.salmonella enterica represents a major human and animal pathogen. many s. enterica genomes have been completed and many more genome sequencing projects are underway, constituting an excellent resource for comparative genome analysis studies leading to a better understanding of bacterial evolution and pathogenesis. salmonella enterica serovar typhimurium and typhi are the best-characterized serovars, with the first being involved in localized gastroenteritis in many hosts and the latter causing a ...201020146749
salmonella enterica serovar typhimurium vaccine strains expressing a nontoxic shiga-like toxin 2 derivative induce partial protective immunity to the toxin expressed by enterohemorrhagic escherichia coli.shiga-like toxin 2 (stx2)-producing enterohemorrhagic escherichia coli (referred to as ehec or stec) strains are the primary etiologic agents of hemolytic-uremic syndrome (hus), which leads to renal failure and high mortality rates. expression of stx2 is the most relevant virulence-associated factor of ehec strains, and toxin neutralization by antigen-specific serum antibodies represents the main target for both preventive and therapeutic anti-hus approaches. in the present report, we describe t ...201020147499
elucidation of the outer membrane proteome of salmonella enterica serovar typhimurium utilising a lipid-based protein immobilization technique.salmonella enterica serovar typhimurium (s. typhimurium) is a major cause of human gastroenteritis worldwide. the outer membrane proteins expressed by s. typhimurium mediate the process of adhesion and internalisation within the intestinal epithelium of the host thus influencing the progression of disease. since the outer membrane proteins are surface-exposed, they provide attractive targets for the development of improved antimicrobial agents and vaccines. various techniques have been developed ...201020149234
characterization of antimicrobial resistance, molecular and phage types of salmonella enterica serovar typhi isolations.isolation rates in canada of salmonella enterica serovar typhi increased from 0.29 to 0.55 isolations/100,000 population during 2000-2006. although no ciprofloxacin resistance was detected, nalidixic acid resistance increased from 41% to 80%. multidrug-resistant s. typhi represented 18% of the strains tested. pulsed-field gel electrophoresis (pfge) analysis of 222 isolates resulted in 91 distinct patterns clustering into four major genetic similarity groups. the five most frequently occurring pf ...201020149265
further evidence of plasmid-encoded bla-(ctx-m-15) and bla-(tem-1) genes in lebanese isolates of salmonella enterica serovar typhimurium that produce extended-spectrum beta-lactamase. 201020149296
ribosomes lacking protein s20 are defective in mrna binding and subunit association.the functional significance of ribosomal proteins is still relatively unclear. here, we examined the role of small subunit protein s20 in translation using both in vivo and in vitro techniques. by means of lambda red recombineering, the rpst gene, encoding s20, was removed from the chromosome of salmonella enterica var. typhimurium lt2 to produce a deltas20 strain that grew markedly slower than the wild type while maintaining a wild-type rate of peptide elongation. removal of s20 conferred a sig ...201020149799
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