Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
multiple targets of nitric oxide in the tricarboxylic acid cycle of salmonella enterica serovar typhimurium.host nitric oxide (no·) production is important for controlling intracellular bacterial pathogens, including salmonella enterica serovar typhimurium, but the underlying mechanisms are incompletely understood. s. typhmurium 14028s is prototrophic for all amino acids but cannot synthesize methionine (m) or lysine (k) during nitrosative stress. here, we show that no·-induced mk auxotrophy results from reduced succinyl-coa availability as a consequence of no· targeting of lipoamide-dependent lipoami ...201121767810
another target for no.nitric oxide (no) is a poisonous free radical made by phagocytic cells to combat pathogens. richardson et al. (2011) show that the salmonella enterica serovar typhimurium lipoamide dehydrogenase is a target for the nitrosative stress exerted by no and related reactive nitrogen species.201121767805
characterization of a novel extended-spectrum ß-lactamase phenotype from oxa-1 expression in salmonella typhimurium strains from africa and ireland.salmonella enterica (s. typhimurium) strains from kenya, malawi, and ireland showing elevated cefepime mic values carried bla(oxa-1). these strains were not detected by current guidelines for extended-spectrum ß-lactamase production based on mic values or clavulanate inhibition, since cefepime is a preferred substrate for oxa-1 and this enzyme is reported to be resistant to clavulanate inhibition. bla(oxa-1) was located within a class i integron and an activated p(2) promoter was identified upst ...201121767713
intraperitoneal immunization of recombinant hsp70 (dnak) of salmonella typhi induces a predominant th2 response and protective immunity in mice against lethal salmonella infection.heat shock proteins serve as important antigens in defense against infectious diseases. members of hsp70 family, particularly microbial hsp70s have acquired special significance in immunity. in the present study, we evaluated the immunogenicity and protective efficacy of hsp70 of salmonella enterica serovar typhi against lethal infection by salmonella in mice with or without adjuvants. the hsp70 gene was cloned and expressed in escherichia coli bl21 and purified by affinity chromatography. immun ...201121767594
the heat-resistant agglutinin family includes a novel adhesin from enteroaggregative escherichia coli strain 60a.heat-resistant agglutinin 1 (hra1) is an accessory colonization factor of enteroaggregative escherichia coli (eaec) strain 042. tia, a close homolog of hra1, is an invasin and adhesin that has been described in enterotoxigenic e. coli. we devised a pcr-restriction fragment length polymorphism screen for these genes and found that they occur among 55 (36.7%) of enteroaggregative e. coli screened, as well as lower proportions of enterotoxigenic, enteropathogenic, enterohemorrhagic and commensal e. ...201121764925
metabolomics reveals phospholipids as important nutrient sources during salmonella growth in bile in vitro and in vivo.during the colonization of hosts, bacterial pathogens are presented with many challenges that must be overcome for colonization to successfully occur. this requires bacterial sensing of the surroundings and adaptation to the conditions encountered. one of the major impediments to pathogen colonization of the mammalian gastrointestinal tract is the antibacterial action of bile. salmonella enterica serovar typhimurium has specific mechanisms involved in resistance to bile. additionally, salmonella ...201121764918
oral administration of live attenuated salmonella enterica serovar typhimurium expressing chicken interferon-a alleviates clinical signs caused by respiratory infection with avian influenza virus h9n2.low pathogenic avian influenza (lpai) h9n2 has attracted considerable attention due to severe commercial losses in the poultry industry. furthermore, avian influenza virus (aiv) h9n2-infected chickens can be a reservoir for viral transmission to mammals including pigs and humans, complicating control of viral mutants. chicken interferon-alpha (chifn-a) may be useful as an exogenous antiviral agent to control aiv h9n2 infection. however, a superior vehicle for administration of chifn-a is needed ...201121764226
development and evaluation of gamma irradiated toxoid vaccine of salmonella enterica var typhimurium.development of a single effective vaccine against non-typhoidal salmonellosis is very challenging due to the presence of hundreds of serovars of salmonella which are antigenically different from each other. the salmonella enterotoxin (stn), a common virulence factor occurring amongst a wide range of serovars, used as a formalized toxoid vaccine has been found to be effective against homologous and heterologous serovars. however, the process of formalization has its own drawbacks. gamma radiation ...201121763085
independent evolutionary origins of functional polyamine biosynthetic enzyme fusions catalysing de novo diamine to triamine formation.we have identified gene fusions of polyamine biosynthetic enzymes s-adenosylmethionine decarboxylase (adometdc, sped) and aminopropyltransferase (spee) orthologues in diverse bacterial phyla. both domains are functionally active and we demonstrate the novel de novo synthesis of the triamine spermidine from the diamine putrescine by fusion enzymes from ß-proteobacterium delftia acidovorans and d-proteobacterium syntrophus aciditrophicus, in a ?spede gene deletion strain of salmonella enterica sv. ...201121762220
interkingdom crosstalk: host neuroendocrine stress hormones drive the hemolytic behavior of salmonella typhi.the ability of bacterial pathogens to sense their immediate environment plays a significant role on their capacity to survive and cause disease. salmonella enterica serovar typhi (s. typhi) is an exclusively human pathogen that causes typhoid fever. in a recent study, we have shown that s. typhi senses and responds to host neuroendocrine stress hormones to release the toxin hemolysin e. hormone-mediated hemolysis by s. typhi was inhibited by the ß-blocker propranolol and was dependent on the pre ...201121758008
inhibition studies of the ß-carbonic anhydrases from the bacterial pathogen salmonella enterica serovar typhimurium with sulfonamides and sulfamates.the two ß-carbonic anhydrases (cas, ec 4.2.1.1) from the bacterial pathogen salmonella enterica serovar typhimurium, stca 1 and stca 2, were investigated for their inhibition with a large panel of sulfonamides and sulfamates. unlike inorganic anions, which are weak, millimolar inhibitors of the two enzymes [vullo et al., bioorg. med. chem. lett.2011, 21, 3591], sulfonamides and sulfamates are effective micro-to nanomolar inhibitors of the two enzymes. various types of inhibitors have been detect ...201121757360
bacillus subtilis (dsm17299) significantly reduces salmonella in broilers.salmonella continues to be a major public health burden worldwide. poultry are known to be one of the main reservoirs for this zoonotic pathogen. it has previously been shown that a single dose of bacillus subtilis reduces fecal shedding of salmonella enterica serovar enteritidis, whereas no effect on long-term colonization of the cecum has been observed. here we report experiments that were undertaken to test the efficacy of a conventional diet supplemented with a probiotic (b. subtilis dsm1729 ...201121753205
microencapsulated sorbic acid and nature-identical compounds reduced salmonella hadar and salmonella enteritidis colonization in experimentally infected chickens.the reduction of salmonella prevalence in broilers is a priority in european union agricultural policies because treatment with antibiotics is forbidden by regulation (ec) 2160/2003. two trials were conducted to evaluate the efficacy of a microencapsulated blend of sorbic acid and nature-identical compounds (i.e., chemically synthesized botanicals; sab) on the reduction of the cecal prevalence and contents of salmonella enterica serovars hadar and enteritidis in experimentally infected chickens. ...201121753203
biological activity of twenty-three hydantoin derivatives on intrinsic efflux pump system of salmonella enterica serovar enteritidis nctc 13349.hydantoin derivatives have important biochemical and pharmacological properties. in the present study, 23 hydantoin compounds were evaluated for their efflux-modulating effects in salmonella enterica serovar enteritidis nctc 13349 using real-time fluorimetry based on the intracellular accumulation of ethidium bromide (eb), a universal substrate of efflux pumps.201121753132
outbreak of a novel enterobacter sp. carrying bla(ctx-m-15) in a neonatal unit of a tertiary care hospital in tanzania.enterobacter hormaechei and cronobacter sakazakii are amongst the most important causes of outbreaks of neonatal sepsis associated with powdered milk. in this study, we report for the first time an outbreak of a novel enterobacter sp. harbouring bla(ctx-m-15) in a neonatal unit in tanzania. seventeen gram-negative enteric isolates from neonatal blood cultures were studied. antibiotic susceptibility was assessed by disc diffusion testing, and the presence of the bla(ctx-m-15) gene was established ...201121752606
essential oils from moroccan plants as potential chemosensitisers restoring antibiotic activity in resistant gram-negative bacteria.bacterial drug resistance is a worrying public health problem. antibiotic efflux is a major non-specific resistance mechanism used by bacteria, and efflux pumps are involved in the low-level susceptibility of various important gram-negative pathogens. use of molecules that can block bacterial pumps is an attractive strategy, but several studies report only partial efficacy owing to limits of these molecules (stability, selectivity, bioavailability, toxicity, etc.). the objective of this study wa ...201121752605
impedimetric biosensor based on self-assembled hybrid cystein-gold nanoparticles and cramoll lectin for bacterial lipopolysaccharide recognition.we report the development of a new selective and specific electrochemical biosensor for bacterial lipolysaccharide (lps). an electrode interface was constructed using a l-cysteine-gold nanoparticle (aunpcys) composite to be immobilized by electrostatic interaction in the network of a poly(vinyl chloride-vinyl acetate maleic acid) (pvm) layer on a gold bare electrode. the impedimetric biosensor is fabricated by self-assembled cramoll lectin on the pvm-aunpcys-modified gold electrode through elect ...201121752390
ciprofloxacin-resistant salmonella enterica serotype typhi, united states, 1999-2008.we report 9 ciprofloxacin-resistant salmonella enterica serotype typhi isolates submitted to the us national antimicrobial resistance monitoring system during 1999-2008. the first 2 had indistinguishable pulsed-field gel electrophoresis patterns and identical gyra and parc mutations. eight of the 9 patients had traveled to india within 30 days before illness onset.201121749779
salmonella enterica serotype typhi with nonclassical quinolone resistance phenotype.we report salmonella enterica serotype typhi strains with a nonclassical quinolone resistance phenotype (i.e., decreased susceptibility to ciprofloxacin but with susceptibility to nalidixic acid) associated with a nonsynonymous mutation at codon 464 of the gyrb gene. these strains, not detected by the nalidixic acid disk screening test, can result in fluoroquinolone treatment failure.201121749778
increasing ceftriaxone resistance in salmonellae, taiwan.in taiwan, despite a substantial decline of salmonella enterica serotype choleraesuis infections, strains resistant to ciprofloxacin and ceftriaxone persist. a self-transferable blacmy-2-harboring inci1 plasmid was identified in s. enterica serotypes choleraesuis, typhimurium, agona, and enteritidis and contributed to the overall increase of ceftriaxone resistance in salmonellae.201121749777
establishing streptomycin epidemiological cut-off values for salmonella and escherichia coli.this study was conducted to elucidate the accuracy of the current streptomycin epidemiological cut-off value (ecoff) for escherichia coli and salmonella spp. a total of 236 salmonella enterica and 208 e. coli isolates exhibiting mics between 4 and 32?mg/l were selected from 12 countries. isolates were investigated by polymerase chain reaction for aada, stra, and strb streptomycin resistance genes. out of 236 salmonella isolates, 32 (13.5%) yielded amplicons for aada (n?=?23), stra (n?=?9), and s ...201121749212
salmonella interaction with and passage through the intestinal mucosa: through the lens of the organism.salmonella enterica serotypes are invasive enteric pathogens spread through fecal contamination of food and water sources, and represent a constant public health threat around the world. the symptoms associated with salmonellosis and typhoid disease are largely due to the host response to invading salmonella, and to the mechanisms these bacteria employ to survive in the presence of, and invade through the intestinal mucosal epithelia. surmounting this barrier is required for survival within the ...201121747800
contribution of a streptococcus mutans antigen expressed by a salmonella vector vaccine in dendritic cell activation.a salmonella vector vaccine expressing the saliva-binding region (sbr) of the adhesin agi/ii of streptococcus mutans has been shown to induce a mixed th1/th2 anti-sbr immune response in mice and to require tlr2, tlr4 and myd88 signaling for the induction of mucosal anti-sbr antibody responses. since dendritic cells (dc) are critical in innate and adaptive immunity, the present study assessed the role of sbr expression by the vector vaccine in dc activation. bone marrow-derived dc from wild type, ...201121746857
osteomyelitis due to salmonella enterica subsp. arizonae: the price of exotic pets.clin microbiol infect abstract: we describe a 31-year-old immunocompromised patient who developed sepsis and osteomyelitis due to salmonella enterica subsp. arizonae secondary to exposure to iguana and snakes kept as pets at her home, and review all 23 previously published cases of bone and joint infections due to this organism, for a total of nine children and 15 adults. eleven of the adults were female (73%), compared with three (33%) of the children (p <0.01). significant underlying illnesses ...201121745257
evaluation of salmonella enterica serovar typhimurium and choleraesuis slya mutant strains for use in live attenuated oral vaccines.slya protein plays a key role in virulence in salmonella enterica. in this study, we evaluated the ability of the slya mutant strain of s. enterica serovar choleraesuis (s. choleraesuis) to protect against swine salmonellosis. using a murine model infected with s. enterica serovar typhimurium (s. typhimurium), we showed that the salmonella strain with a deletion of slya could be used as a highly immunogenic, effective and safe vaccine in mice. based on these data, a slya mutant of s. enterica se ...201121840053
transposon tn5393e carrying the apha1-containing transposon tn6023 upstream of strab does not confer resistance to streptomycin.the simplest form of transposon tn5393 carries the stra and strb genes that confer resistance to streptomycin, in addition to its transposition determinants. tn5393e, made up of tn5393 and a second transposon, tn6023, was found in an inchi2 plasmid, psrc125, recovered from a multiply antibiotic-resistant salmonella enterica serovar typhimurium isolate of bovine origin. tn6023 is made up of the apha1b gene flanked by two inversely oriented copies of insertion sequence (is) is26 and is flanked by ...201121702681
salmonella-induced mucosal lectin regiii+¦ kills competing gut microbiota.intestinal inflammation induces alterations of the gut microbiota and promotes overgrowth of the enteric pathogen salmonella enterica by largely unknown mechanisms. here, we identified a host factor involved in this process. specifically, the c-type lectin regiii+¦ is strongly upregulated during mucosal infection and released into the gut lumen. in vitro, regiii+¦ kills diverse commensal gut bacteria but not salmonella enterica subspecies i serovar typhimurium (s. typhimurium). protection of the ...201121694778
contaminated commercial dehydrated food as source of multiple salmonella serotypes outbreak in a municipal kennel in tuscany.the authors describe a large outbreak of canine salmonellosis in a municipal kennel in tuscany. during the outbreak, 174 samples of 'diarrhetic' and 'normal' faeces and two batches of commercial dehydrated dog food were cultured for pathogenic bacteria. the results of 25, out of a total of 41 dogs (60.9%) revealed at least one faecal sample as being positive for salmonella; incidence per sampling ranged from 12.5% to 34%. nine of 10 samples of dehydrated food were positive. ten totally different ...201121706471
treatment of typhoid fever in the 21st century: promises and shortcomings.emergence of multidrug resistance and decreased ciprofloxacin susceptibility (dcs) in salmonella enterica serovar typhi in south asia have rendered older drugs, including ampicillin, chloramphenicol, trimethoprim-sulphamethoxazole, ciprofloxacin, and ofloxacin, ineffective or suboptimal for typhoid fever. ideally, treatment should be safe and available for adults and children in shortened courses of 5 days, cause defervescence within 1 week, render blood and stool cultures sterile, and prevent r ...201121722249
rhizosphere effect on survival of escherichia coli o157:h7 and salmonella enterica serovar typhimurium in manure-amended soil during cabbage (brassica oleracea) cultivation under tropical field conditions in sub-saharan africa.the effect of cabbage (brassica oleracea) rhizosphere on survival of escherichia coli o157:h7 and salmonella typhimurium in manure-amended soils under tropical field conditions was investigated in the central agro-ecological zone of uganda. three-week old cabbage seedlings were transplanted and cultivated for 120days on manure-amended soil inoculated with 4 or 7log cfu/g non-virulent e. coli o157:h7 and s. typhimurium. cabbage rhizosphere did not affect survival of the 4log cfu/g inocula in manu ...201121741722
evaluation of antibacterial activity against salmonella enteritidis.salmonella enterica serovar enteritidis is a well-known pathogenic bacterium responsible for human gastrointestinal enteritis mainly due to the consumption of eggs and egg-products. the first aim of this work was to study several virulence factors of a strain isolated from egg content: seovo. first, bacterial growth was studied at several temperatures and cell morphology was observed by scanning electronic microscopy. these experiments showed salmonella's ability to grow at low temperatures and ...201121717317
emergence of multi-drug resistant salmonella enterica serotype stanleyville infections among children in yaounde, cameroon. 201121712305
antioxidant oils and salmonella enterica typhimurium reduce tumor in an experimental model of hepatic metastasis.fruit seeds high in antioxidants have been shown to have anticancer properties and enhance host protection against microbial infection. recently we showed that a single oral dose of salmonella enterica serovar typhimurium expressing a truncated human interleukin-2 gene (salpil2) is avirulent, immunogenic, and reduces hepatic metastases through increased natural killer cell populations in mice. to determine whether antioxidant compounds enhance the antitumor effect seen in salpil2-treated animals ...201121691578
effects of two simulated oxytetracycline dosing regimens on horizontal transfer of antimicrobial resistance plasmids in an in vitro pharmacodynamic model.to evaluate the impact of oxytetracycline exposure on horizontal transfer of an antimicrobial resistance plasmid.201121728847
immunization of chickens with salmonella enterica subspecies enterica serovar enteritidis pathogenicity island-2 proteins.several structural components of the type iii secretion systems (t3ss) encoded by salmonella pathogenicity island (spi)-1 and spi-2 are exposed to the host's immune system prior to/during the infection/invasion process, making them potential vaccine candidates. in this study we evaluated whether chickens vaccinated with spi-2 t3ss components could mount a significant humoral immune response (as measured by serum igg titres) and whether these antibodies could be transferred to progeny (as measure ...201121684090
occurrence of incfii plasmids carrying the bla(ctx-m-15) gene in salmonella enterica serovar enteritidis sequence type 11 in korea.a total of 49 consecutive nonduplicate salmonella isolates collected in a nationwide survey performed in 2009 in korea were included in this study. resistance gene, sizes, and replicon sequence types (rsts) of r plasmids, and sequence types (sts) and xbai-macrorestriction patterns of extended-spectrum +¦-lactamase (esbl)-producing isolates were determined. six salmonella enterica serovar enteritidis isolates of st11 showed esbl phenotypes, and the isolates harbored an incompatibility group fii p ...201121840672
application of variable number of tandem repeat analysis to track salmonella enterica ssp. enterica serovar typhimurium infection of pigs reared on three british farms through the production cycle to the abattoir.aims:ôçé this study investigated the diversity and persistence of salmonella strains through the pork finishing cycle, from the farm into the abattoir. methods and results:ôçé isolates from four batches of finishers, from farm to abattoir, were used. salmonella typhimurium isolates were subjected to molecular typing using pulsed-field gel electrophoresis and variable number of tandem repeat analysis. the results demonstrated that infection was transferred from the farm to the abattoir. within th ...201121722278
foodborne outbreak of salmonella subspecies iv infections associated with contamination from bearded dragons.approximately 1.4 million salmonella infections and 400 deaths occur annually in the united states. approximately 6% of human salmonella cases are thought to be associated with reptiles; salmonella enterica subspecies iv is primarily reptile-associated. during 1-4 december, 2009, three isolates of salmonella iv 6,7:z4,z24:- with indistinguishable pulsed-field gel electrophoresis (pfge) patterns were identified through minnesota department of health laboratory-based surveillance. none of the thre ...201121824356
a multiplex real-time pcr assay targeting virulence and resistance genes in salmonella enterica serotype typhimurium.abstract:201121707966
b cell priming for extrafollicular antibody responses requires bcl-6 expression by t cells.t follicular helper cells (tfh cells) localize to follicles where they provide growth and selection signals to mutated germinal center (gc) b cells, thus promoting their differentiation into high affinity long-lived plasma cells and memory b cells. t-dependent b cell differentiation also occurs extrafollicularly, giving rise to unmutated plasma cells that are important for early protection against microbial infections. bcl-6 expression in t cells has been shown to be essential for the formation ...201121708925
a food borne outbreak of salmonella enterica serotype brandenburg as a hint to compare human, animal and food isolates identified in the years 2005-2009 in italy.there are only a few reported cases of salmonella enterica serotype brandenburg foodborne outbreaks in the literature. in italy brandenburg is consistently present among the top ten serotypes from human source, but at low prevalences.201121710817
coiled-coil domains enhance the membrane association of salmonella type iii effectors.coiled-coil domains in eukaryotic and prokaryotic proteins contribute to diverse structural and regulatory functions. here we have used in silico analysis to predict which proteins in the proteome of the enteric pathogen, salmonella enterica serovar typhimurium, harbour coiled-coil domains. we found that coiled-coil domains are especially prevalent in virulence-associated proteins, including type iii effectors. using sopb as a model coiled-coil domain type iii effector, we have investigated the ...201121679290
antimicrobial susceptibility to azithromycin among salmonella enterica isolates from the united states.due to emerging resistance to traditional antimicrobial agents, such as ampicillin, trimethoprim-sulfamethoxazole, and chloramphenicol, azithromycin is increasingly used for the treatment of invasive salmonella infections. in the present study, 696 isolates of non-typhi salmonella collected from humans, food animals, and retail meats in the united states were investigated for antimicrobial susceptibility to azithromycin. seventy-two salmonella enterica serotype typhi isolates from humans were al ...201121690279
salmonella typhimurium invasion of hep-2 epithelial cells in vitro is increased by n-acylhomoserine lactone quorum sensing signals.in gram-negative bacteria, the most commonly studied quorum sensing signals are the n-acylhomoserine lactones (ahls). in salmonella, ahls are recognized by sdia, which is believed to be a sensor of ahls produced by other bacteria, since salmonella does not produce ahls itself. it has been speculated that ahls produced by the gastrointestinal flora may influence the regulation of virulence traits in salmonella. the aim of the present work was to study the effect of ahls on epithelial cell invasio ...201121711544
management of quinolone-resistant typhoid osteomyelitis. 201121841594
the utility of diagnostic tests for enteric fever in endemic locations.enteric fever, an infection caused by salmonella enterica serovar typhi and serovar paratyphi a, is common and endemic in many areas of the asian and african continents. in endemic areas, diagnostic tests are needed to diagnose acute cases for clinical management, to detect convalescent and chronic fecal carriage and for contact tracing. a suitable test may also allow an assessment of disease burden in a community to determine the need for vaccination programs. each specific role may warrant a d ...201121692675
comparative genomics and phylogeny of the inci1 plasmids: a common plasmid type among porcine enterotoxigenic escherichia coli.increasing reports of multidrug resistance conferred by conjugative plasmids of enterobacteriaceae necessitate a better understanding of their evolution. one such group is the narrow-host-range inci1 plasmid type, known for their ability to carry genes encoding resistance to extended-spectrum beta lactamases. the focus of this study was to perform comparative sequencing of inci1 plasmids from porcine enterotoxigenic escherichia coli (etec), isolated irrespective of antimicrobial susceptibility p ...201121843549
immunization with an anti-idiotypic antibody against the broadly lipopolysaccharide-reactive antibody wn1 222-5 induces escherichia coli r3-core-type specific antibodies in rabbits.the mouse monoclonal antibody (mab) wn1 222-5 recognizes a carbohydrate epitope in the inner core region of lps that is shared by all strains of escherichia coli and salmonella enterica and is able to neutralize their endotoxic activity in vitro and in vivo. immunization of mice with mab wn1 222-5 yielded several anti-idiotypic mabs one of which (mab s81-19) competitively inhibited binding of mab wn1 222-5 to e. coli and salmonella lps. after immunization of rabbits with mab s81-19, the serologi ...201121844130
impairment of swimming motility by antidiarrheic lactobacillus acidophilus strain lb retards internalization of salmonella enterica serovar typhimurium within human enterocyte-like cells.we report that the culture and cell-free culture supernatant (cfcs) of l. acidophilus lb have the ability: (i) to delay the appearance of s. typhimurium sl1344-induced mobilization of f-actin; and (ii) subsequently, to retard the cell-entry of s. typhimurium sl1344. time-lapse imaging and western immunoblotting showed that the s. typhimurium sl1344 swimming motility cell-track types were rapidly but temporarily blocked without affecting the expression of flic flagellar propeller protein. we show ...201121825295
in vitro and in vivo synergistic effects of cryptdin 2 and ampicillin against salmonella.in view of the emergence of multidrug-resistant salmonella strains, there is a need for therapeutic alternatives. to reduce the dose of antibiotic required in order to decrease the associated side effects, the present study was aimed at evaluating the synergism between cryptdin 2 (a paneth cell antimicrobial peptide) and ampicillin (amp) against salmonella enterica serovar typhimurium. the synergy was evaluated in terms of the fractional bactericidal concentration (fbc) index, time-kill assay re ...201121690282
physico-chemical properties of salmonella typhi vi polysaccharide-diphtheria toxoid conjugate vaccines affect immunogenicity.in this study it was demonstrated that the immunogenicity of vi polysaccharide-diphtheria toxoid conjugates was related to the physical and chemical structure of the conjugate. conjugates were prepared in two steps, firstly binding adipic acid dihydrazide (adh) spacer molecules to diphtheria toxoid (dt) carrier protein then secondly binding varying amounts of this derivatized dt to a fixed amount of vi capsular polysaccharide purified from salmonella enterica serovar typhi. as the amount of dt b ...201121843575
salmonella exploits arl8b-directed kinesin activity to promote endosome tubulation and cell-to-cell transfer.the facultative intracellular pathogen salmonella enterica serovar typhimurium establishes a replicative niche, the salmonella-containing vacuole (scv), in host cells. here we demonstrate that these bacteria exploit the function of arl8b, an arf family gtpase, during infection. following infection, arl8b localized to scvs and to tubulated endosomes that extended along microtubules in the host cell cytoplasm. arl8b(+) tubules partially colocalized with lamp1 and scamp3. formation of lamp1(+) tubu ...201121824248
a salmonella typhimurium-typhi genomic chimera: a model to study vi polysaccharide capsule function in vivo.the vi capsular polysaccharide is a virulence-associated factor expressed by salmonella enterica serotype typhi but absent from virtually all other salmonella serotypes. in order to study this determinant in vivo, we characterised a vi-positive s. typhimurium (c5.507 vi(+)), harbouring the salmonella pathogenicity island (spi)-7, which encodes the vi locus. s. typhimurium c5.507 vi(+) colonised and persisted in mice at similar levels compared to the parent strain, s. typhimurium c5. however, the ...201121829346
detection and characterization of mycoplasma spp. and salmonella spp. in free-living european tortoises (testudo hermanni, testudo graeca, and testudo marginata).free-living and captive chelonians might suffer from upper respiratory tract disease (urtd), a pathology primarily caused by mycoplasma agassizii. wild tortoises can also be an important reservoir of salmonella spp., which are commensal in the host reptile but are potential zoonotic agents. between july 2009 and june 2010, we screened free-living european tortoises (spur-thighed tortoises testudo graeca, hermann's tortoises testudo hermanni, marginated tortoises testudo marginata) temporarily ho ...201121719840
the rhodanese domain of thii is both necessary and sufficient for synthesis of the thiazole moiety of thiamine in salmonella enterica.in salmonella enterica, thii is a bifunctional enzyme required for the synthesis of both the 4-thiouridine modification in trna and the thiazole moiety of thiamine. in 4-thiouridine biosynthesis, thii adenylates the trna uridine and transfers sulfur from a persulfide formed on the protein. the role of thii in thiazole synthesis is not yet well understood. mutational analysis described here found that thii residues required for 4-thiouridine synthesis were not involved in thiazole biosynthesis. t ...201121724998
rapid genoserotyping tool for classification of salmonella serovars.we have developed a salmonella genoserotyping array (sgsa) which rapidly generates an antigenic formula consistent with the white-kauffmann-le minor scheme, currently the gold standard for salmonella serotyping. a set of 287 strains representative of 133 salmonella serovars was assembled to validate the array and to test the array probes for accuracy, specificity, and reproducibility. initially, 76 known serovars were utilized to validate the specificity and repeatability of the array probes and ...201121697324
the non-motile phenotype of salmonella hha ydgt mutants is mediated through pefi-srgd.two ancestral nucleoid-associated proteins called hha and ydgt contribute to the negative regulation of several virulence-associated genes in salmonella enterica serovar typhimurium. our previous work showed that hha and ydgt proteins are required for negative regulation of salmonella pathogenicity island-2 and that hha ydgt double mutants are attenuated for murine infection. interestingly, hha ydgt mutant bacteria exhibited a non-motile phenotype suggesting that hha and ydgt have a role in flag ...201121689395
investigation of diversity of plasmids carrying the blatem-52 gene.objectives to investigate the diversity of plasmids that carry bla(tem-52) genes among escherichia coli and salmonella enterica originating from animals, meat products and humans. methods a collection of 22 bla(tem-52)-encoding plasmids was characterized by restriction fragment length polymorphism (rflp), replicon typing (by pcr or replicon sequencing), susceptibility testing, assessment of plasmid ability to self-transfer by conjugation and typing of the genetic environment of the bla(tem-52) g ...201121831988
molecular characterisation of multidrug-resistant salmonella enterica serotype infantis from humans, animals and the environment in italy.during 2005-2006, salmonella enterica serotype infantis strains isolated from human and non-human sources and resistant to ampicillin (a), chloramphenicol (c), streptomycin (s), sulphonamide (su), tetracycline (t), kanamycin (k) and trimethoprim/sulfamethoxazole (sxt) emerged in italy. the aim of this study was to analyse the molecular basis of antibiotic resistance and to evaluate the clonal origin of multiresistant s. infantis strains isolated from different sources. seventy s. infantis strain ...201121821397
molecular and comparative analysis of salmonella enterica senftenberg from humans and animals using pfge, mlst and narms.salmonella species are recognized worldwide as a significant cause of human and animal disease. in this study the molecular profiles and characteristics of salmonella enterica senftenberg isolated from human cases of illness and those recovered from healthy or diagnostic cases in animals were assessed. included in the study was a comparison with our own sequenced strain of s. senfteberg recovered from production turkeys in north dakota. isolates examined in this study were subjected to antimicro ...201121708021
phylogenetic relationship of salmonella enterica strains in tehran, iran, using 16s rrna and gyrb gene sequences.we assessed whether 16s rdna and gyrb gene sequences, alone or combined, were suitable for determining the phylogenetic relationship among salmonella enterica strains isolated from tehran, iran. patients over five years of age enrolled in an acute diarrheal surveillance project in tehran province between may 2004 and october 2006 were selected as our study group.201121727646
effect of growth under selection on appearance of chromosomal mutations in salmonella enterica.populations adapt physiologically using regulatory mechanisms and genetically by means of mutations that improve growth. during growth under selection, genetic adaptation can be rapid. in several genetic systems, the speed of adaptation has been attributed to cellular mechanisms that increase mutation rates in response to growth limitation. an alternative possibility is that growth limitation serves only as a selective agent but acts on small-effect mutations that are common under all growth con ...201121705757
modification of technical properties of lactobacillus johnsonii ncc 533 by supplementing growth medium with unsaturated fatty acids.the aim of this study was to investigate the influence of supplementing growth media with unsaturated fatty acids on the technical properties of the probiotic strain lactobacillus johnsonii ncc 533, such as heat and acid tolerance, and inhibition of salmonella typhimurium infection. our results showed that the membrane composition and morphology of l. johnsonii ncc 533 was significantly changed by supplementing a minimal lactobacillus media with oleic, linoleic and linolenic acids. the ratio of ...201121821758
deletion of the acee gene (encoding a component of pyruvate dehydrogenase) attenuates salmonella enterica serovar enteritidis.salmonella enterica serovar enteritidis (s. enteritidis) is a major food-borne pathogen. from a transposon insertion mutant library created previously using s. enteritidis 10/02, one of the mutants was identified to have a 50% lethal dose (ld(50) ) at least 100 times that of the parental strain in young chicks, with an attenuation in a poorly studied gene encoding a component of pyruvate dehydrogenase, namely the acee gene. evaluation of the in vitro virulence characteristics of the +öaceeôêàkan ...201121707778
reactive arthritis in a population exposed to an extensive waterborne gastroenteritis outbreak after sewage contamination in pirkanmaa, finland.objectives: to assess the occurrence, clinical picture, and triggering infections of reactive arthritis (rea) associated with a large waterborne gastroenteritis outbreak. methods: after an extensive sewage contamination of the water supply system, an estimated 8453 of the 30 016 inhabitants of the town of nokia fell ill. general practitioners and occupational physicians were advised to refer any patients with suspicion of new rea to rheumatological examination including faecal culture, human leu ...201121679096
a new rapid and micro-scale hydrolysis, using triethylamine citrate, for lipopolysaccharide characterization by mass spectrometry.endotoxin (lipopolysaccharide, lps) is, in general, composed of two moieties: a hydrophilic polysaccharide linked to a hydrophobic lipid a terminal unit and forms a major surface component of gram-negative bacteria. the structural features of lps moieties play a role in pathogenesis and also involve immunogenicity and diagnostic serology. the major toxic factor of lps resides in the lipid a moiety, anchored in the outer layer of the bacterium, and its relative biological activity is critically r ...201121698687
the pmra/pmrb regulatory system controls the expression of the wzzfepe gene involved in the o-antigen synthesis of salmonella enterica serovar typhimurium.the degree of polymerization of o-antigen from salmonella enterica serovar typhimurium is controlled by the products of the wzz(s)(t) and wzz(fepe) genes. in the present study we investigated the role of the pmra/pmrb regulatory system in wzz(fepe) transcription. we report that the direct binding of the pmra regulator to a specific promoter site induces the expression of the wzz(fepe) gene. this effect increases the amount of very long (vl) o-antigen, which is required for the resistance of salm ...201121719537
safety and efficacy of a virulence gene-deleted live vaccine candidate for fowl typhoid in young chickens.the safety and efficacy of a live lon-and-cpxr-deleted salmonella enterica serovar gallinarum (sg) vaccine candidate (jol916) was evaluated in young layer chickens. vaccinated (n=25) and unvaccinated (n=25) groups were organized, respectively, at 1, 2, 3, and 4 weeks of age. one-week-old and 2-week-old chickens were orally inoculated with 2+ù10(7) colony-forming units of jol916, and orally challenged with 2 x 10(6) colony-forming units of a wild-type sg strain at the third week post vaccination ...201121711190
a nationwide outbreak of salmonella bovismorbificans associated with sprouted alfalfa seeds in finland, 2009.salmonella enterica serotype bovismorbificans is a rare serotype in finland. in june 2009, a nationwide outbreak of s. bovismorbificans infections occurred, and 42 clinical isolates were identified. we conducted a case-control study enrolling 28 cases and 48 matched controls, and found ready-to-eat alfalfa sprouts associated with the infection (odds ratioôçâ=ôçâ35.2, 95% confidence interval 2.8-435). the sprouts were traced back to a domestic producer, with the seeds originating in italy. althou ...201121824360
recombination and population structure in salmonella enterica.salmonella enterica is a bacterial pathogen that causes enteric fever and gastroenteritis in humans and animals. although its population structure was long described as clonal, based on high linkage disequilibrium between loci typed by enzyme electrophoresis, recent examination of gene sequences has revealed that recombination plays an important evolutionary role. we sequenced around 10% of the core genome of 114 isolates of enterica using a resequencing microarray. application of two different ...201121829375
the dickeya dadantii biofilm matrix consists of cellulose nanofibers and is an emergent property dependent upon the type iii secretion system and the cellulose synthesis operon.dickeya dadantii is a plant pathogenic bacterium that produces cellulose-containing biofilms, called pellicles, at the air-liquid interface of liquid cultures. d. dadantii pellicle formation appears to be an emergent property dependent upon at least three gene clusters, including cellulose synthesis, type iii secretion system (t3ss), and flagellar genes. the d. dadantii cellulose synthesis operon is homologous to that of gluconacetobacter xylinus, which is used for industrial cellulose productio ...201121719543
how salmonella oxidises h(2) under aerobic conditions.salmonella enterica serovar typhimurium is a gram negative bacterial pathogen and a common cause of food-borne illness. molecular hydrogen has been shown to be a key respiratory electron donor during infection and h(2) oxidation can be catalysed by three genetically-distinct [nife] hydrogenases. of these, hydrogenases-1 (hyd-1) and hyd-2 have well-characterised homologues in escherichia coli. the third, designated hyd-5 here, is peculiar to salmonella and is expressed under aerobic conditions. i ...201121827758
characterization of d-boroala as a novel broad spectrum antibacterial agent targeting d-ala-d-ala ligase.d-boroala was previously characterized as an inhibitor of bacterial alanine racemase and d-ala-d-ala ligase enzymes [duncan, k., et al biochemistry 1989, 28:3541-9]. in the present study, d-boroala was identified and characterized as an antibacterial agent. d-boroala has activity against both gram-positive and gram-negative organisms, with mics down to 8 ++g/ml. a structure-function study on the alkyl side chain (nh(2) -chr-b(or')(2) ) revealed that d-boroala is the most effective agent in a ser ...201121827632
exposure of salmonella enterica serovar typhimurium to high level biocide challenge can select multidrug resistant mutants in a single step.biocides are crucial to the prevention of infection by bacteria, particularly with the global emergence of multiply antibiotic resistant strains of many species. concern has been raised regarding the potential for biocide exposure to select for antibiotic resistance due to common mechanisms of resistance, notably efflux.201121829527
transcriptional priming of salmonella pathogenicity island-2 precedes cellular invasion.invasive salmonellosis caused by salmonella enterica involves an enteric stage of infection where the bacteria colonize mucosal epithelial cells, followed by systemic infection with intracellular replication in immune cells. the type iii secretion system encoded in salmonella pathogenicity island (spi)-2 is essential for intracellular replication and the regulators governing high-level expression of spi-2 genes within the macrophage phagosome and in inducing media thought to mimic this environme ...201121738750
effect of biofilm formation on the excretion of salmonella enterica serovar typhi in feces.objectives: we hypothesized that salmonella enterica serovar typhi (s. typhi) with higher biofilm and capsule production capability are more able to survive continuously in typhoid patients/carriers, with subsequent prolonged shedding in feces. methods: bacterial cell release from biofilm (produced in vitro and confirmed by specific staining and electron microscopy) and comparative cytotoxicity were studied on caco2 cells. functionality of the biofilm diffusion barrier was tested against ciprofl ...201121816646
the influence of reduced susceptibility to fluoroquinolones in salmonella enterica serovar typhi on the clinical response to ofloxacin therapy.infection with salmonella enterica serovar typhi (s. typhi) with reduced susceptibility to fluoroquinolones has been associated with fluoroquinolone treatment failure. we studied the relationship between ofloxacin treatment response and the ofloxacin minimum inhibitory concentration (mic) of the infecting isolate. individual patient data from seven randomised controlled trials of antimicrobial treatment in enteric fever conducted in vietnam in which ofloxacin was used in at least one of the trea ...201121713025
salmonella enteritidis universal stress protein (usp) gene expression is stimulated by egg white and supports oviduct colonization and egg contamination in laying hens.salmonella enterica subspecies enterica serovar enteritidis has caused a worldwide egg-associated pandemic since the mid 1980s. the exact mechanisms causing this egg tropism are still largely unknown, and only a few salmonella genes have been implicated in the interaction with the oviduct or eggs. a in vivo expression technology screening performed previously, identified the uspa and uspb genes as being highly expressed in the chicken oviduct and in eggs. here, we demonstrate that uspa and uspb ...201121715109
salmonella - at home in the host cell.the gram-negative bacterium salmonella enterica has developed an array of sophisticated tools to manipulate the host cell and establish an intracellular niche, for successful propagation as a facultative intracellular pathogen. while salmonella exerts diverse effects on its host cell, only the cell biology of the classic "trigger"-mediated invasion process and the subsequent development of the salmonella-containing vacuole have been investigated extensively. these processes are dependent on coho ...201121687432
effects of orally administered bdellovibrio bacteriovorus on the well-being and salmonella colonization of young chicks.bdellovibrio bacteriovorus is a bacterium which preys upon and kills gram-negative bacteria, including the zoonotic pathogens escherichia coli and salmonella. bdellovibrio has potential as a biocontrol agent, but no reports of it being tested in living animals have been published, and no data on whether bdellovibrio might spread between animals are available. in this study, we tried to fill this knowledge gap, using b. bacteriovorus hd100 doses in poultry with a normal gut microbiota or predosed ...201121705523
cora, the magnesium/nickel/cobalt transporter, affects virulence and extracellular enzyme production in the soft rot pathogen pectobacterium carotovorum.pectobacterium carotovorum (formerly erwinia carotovora ssp. carotovora) is a phytopathogenic bacterium that causes soft rot disease, characterized by water-soaked soft decay, resulting from the action of cell wall-degrading exoenzymes secreted by the pathogen. virulence in soft rot bacteria is regulated by environmental factors, host and bacterial chemical signals, and a network of global and gene-specific bacterial regulators. we isolated a mini-tn5 mutant of p. carotovorum that is reduced in ...201121726393
integration host factor alleviates h-ns silencing of the salmonella enterica serovar typhimurium master regulator of spi1, hila.coordination of the expression of salmonella enterica invasion genes on salmonella pathogenicity island 1 (spi1) depends on a complex circuit involving several regulators that converge on expression of the hila gene, which encodes a transcriptional activator (hila) that modulates expression of the spi1 virulence genes. two of the global regulators that influence hila expression are the nucleoid-associated proteins hha and h-ns. they interact and form a complex that modulates gene expression. a c ...201121680637
the n-terminal region of the medium subunit (pdud) packages adenosylcobalamin-dependent diol dehydratase (pducde) into the pdu microcompartment.salmonella enterica produces a proteinaceous microcompartment for b(12)-dependent 1,2-propanediol utilization (pdu mcp). the pdu mcp consists of catabolic enzymes encased within a protein shell and its function is to sequester propionaldehyde, a toxic intermediate of 1,2-propanediol degradation. here, we report that a short n-terminal region of the medium subunit (pdud) is required for packaging the coenzyme b(12)-dependent diol dehydratase (pducde) into the lumen of the pdu mcp. analysis of sol ...201121821773
adaptation to the chicken intestine in salmonella enteritidis pt4 studied by transcriptional analysis.the transcriptional changes that occurred in salmonella enterica serovar enteritidis during colonization of the alimentary tract of newly hatched chickens were studied. a whole genome oligonucleotide microarray was used to compare the expression pattern with that from bacteria cultured in nutrient broth in vitro. amongst other changes salmonella pathogenicity island (spi)-1, spi-2 and spi-5 genes were up-regulated in vivo suggesting a close association with the mucosa during colonization. partic ...201121831537
[osteomyelitis of the costae caused by salmonella.]salmonella enterica serotype enteritidis was detected in a 34-year-old, previously healthy patient who suffered from osteomyelitis of the costae. radical surgical debridement and antibiotic therapy were able to stop the infection. an abdominal flap and a thoracic flap were used to cover the soft tissue defect.201121826496
antimicrobial resistance in enteric pathogens isolated from minnesota pigs from 1995 to 2004.this study investigated the occurrence and antimicrobial resistance profiles of escherichia coli and salmonella sp. isolated from swine samples submitted to the minnesota veterinary diagnostic laboratory (mvdl) in saint paul, minnesota from 1995 to 2004. during this time period, a total of 5072 e. coli and 2793 salmonella sp. was isolated. most of these isolates were found to be resistant to the tetracycline and beta-lactam group of antibiotics. resistance to spectinomycin was also frequently ob ...201121731182
nifedipine affects the course of salmonella enterica serovar typhimurium infection by modulating macrophage iron homeostasis.background.ôçâiron overload can adversely influence the course of infection by increasing microbial replication and suppressing antimicrobial immune effector pathways. recently, we have shown that the calcium channel blocker nifedipine can mobilize tissue iron in mouse models of iron overload. we therefore investigated whether nifedipine treatment affects the course of infection with intracellular bacteria via modulation of iron homeostasis. methods. the effect of nifedipine on intramacrophage r ...201121844295
tammar wallaby mammary cathelicidins are differentially expressed during lactation and exhibit antimicrobial and cell proliferative activity.cathelicidins secreted in milk may be central to autocrine feedback in the mammary gland for optimal development in addition to conferring innate immunity to both the mammary gland and the neonate. this study exploits the unique reproductive strategy of the tammar wallaby (macropus eugenii) model to analyse differential splicing of cathelicidin genes and to evaluate the bactericidal activity and effect of the protein on mammary epithelial cell proliferation. two linear peptides, con73 and con218 ...201121824524
antimicrobial resistance and virulence determinants in european salmonella genomic island 1-positive salmonella enterica isolates from different origins.salmonella genomic island 1 (sgi1) contains a multidrug resistance region conferring the ampicillin-chloramphenicol-streptomycin-sulfamethoxazole-tetracycline resistance phenotype encoded by bla(pse-1), flor, aada2, sul1, and tet(g). its increasing spread via interbacterial transfer and the emergence of new variants are important public health concerns. we investigated the molecular properties of sgi1-carrying salmonella enterica serovars selected from a european strain collection. a total of 38 ...201121705546
antimicrobial resistance trends in blood culture positive salmonella typhi isolates from pondicherry, india, 2005-2009.clin microbiol infect abstract: typhoid fever is caused by salmonella enterica serovar typhi, a major public health concern in developing countries. recently, there has been an upsurge in the occurrence of bacterial isolates that are resistant to ciprofloxacin, and the emergence of broad spectrum +¦-lactamases in typhoidal salmonellae constitutes a new challenge for the clinician. a total of 337 blood culture isolates of s.-átyphi, isolated from pondicherry, india, between january 2005 and decem ...201121714829
small-molecular virulence inhibitors show divergent and immunomodulatory effects in infection models of salmonella enterica serovar typhimurium.the virulence-associated salmonella pathogenicity island 2 (spi2) type iii secretion system supports intracellular replication of salmonella enterica serovar typhimurium in macrophage-like raw264.7 cells. in contrast, the salicylidene acylhydrazide inp0010 and the benzimidazole omeprazole prevent virulence factor-mediated replication of s. typhimurium in these cells. here we show that inp0010 enhances expression of inducible nitric oxide synthase (inos), nitric oxide (no) production, the oxidati ...201121821398
enhanced protection against infection with transmissible gastroenteritis virus in piglets by oral co-administration of live attenuated salmonella enterica serovar typhimurium expressing swine interferon-+¦ and interleukin-18.the enhanced effect of cytokine combinations has been assessed empirically, based on their immunobiological mechanisms. however, far less is known of the enhanced protection of practical cytokine combinations against viral infection in the livestock industry, due to cost and production issues associated with mass administration. this study demonstrates the enhanced protection of oral co-administration of swine interferon-+¦ (swifn-+¦) and interleukin-18 (swil-18) against infection with transmiss ...201121719106
high hydrostatic pressure processing reduces salmonella enterica serovars in diced and whole tomatoes.fresh and fresh-cut tomatoes have been associated with numerous outbreaks of salmonellosis in recent years. one effective post harvest treatment to reduce salmonella enterica in tomatoes may be high pressure processing (hpp). the objectives of the study were to determine the potential for hpp to reduce s. enterica serovars newport, javiana, braenderup and anatum in tryptic soy broth (tsb) and to determine the effect of hpp to reduce the most pressure resistant of the four serovars from fresh dic ...201121719138
microarray based analysis of inca/c plasmid associated genes from multidrug resistant salmonella enterica.in enterobacteriaceae, plasmids have been classified according to 27 incompatibility (inc) or replicon types which are based on the inability of different plasmids with the same replication mechanism to co-exist in the same cell. certain replicon types such as inca/c are associated with multidrug resistance (mdr). we developed a microarray that contains 286 unique 70 mer oligonucleotide probes based on sequences from five inca/c plasmids: pyr1 (yersinia ruckeri), ppip1202 (yersinia pestis), pp99 ...201121841024
The Cost of Virulence: Retarded Growth of Salmonella Typhimurium Cells Expressing Type III Secretion System 1.Virulence factors generally enhance a pathogen's fitness and thereby foster transmission. However, most studies of pathogen fitness have been performed by averaging the phenotypes over large populations. Here, we have analyzed the fitness costs of virulence factor expression by Salmonella enterica subspecies I serovar Typhimurium in simple culture experiments. The type III secretion system ttss-1, a cardinal virulence factor for eliciting Salmonella diarrhea, is expressed by just a fraction of t ...201121829349
Prevalence of Salmonella, Yersinia and Campylobacter spp. in Feral Raccoons (Procyon lotor) and Masked Palm Civets (Paguma larvata) in Japan.To estimate the public and animal health risk that alien species pose, the prevalence of Salmonella, Yersinia, and Campylobacter spp. in feral raccoons (Procyon lotor, nÔÇâ=ÔÇâ459) and masked palm civets (Paguma larvata, nÔÇâ=ÔÇâ153), which are abundant alien species in Japan, was investigated in urban and suburban areas of Japan. Salmonella enterica was detected from 29 samples [26 raccoons, 5.7%, 95% confidence interval (CI) 7.8-3.5%; three masked palm civets, 2.0%, 95% CI 4.2-0%]. Many of the ...201121824337
Reduced invasion to human epithelial cell lines of Salmonella enterica serovar Typhi carrying S. Typhimurium sopD2.Salmonella enterica serovar Typhi and Typhimurium are closely related serovars. However, S. Typhi, a human-specific pathogen, has 5% of genes as pseudogenes, far more than S. Typhimurium, which only has 1%. One of these pseudogenes corresponds to sopD2, which in S. Typhimurium encodes an effector protein involved in Salmonella-containing vacuole biogenesis in human epithelial cell lines, which is needed for full virulence of the pathogen. We investigated whether S. Typhi trans-complemented with ...201121707735
Characterization of Salmonella enterica Serovar Typhimurium Isolates Harboring a Chromosomally Encoded CMY-2 {beta}-Lactamase Gene Located on a Multidrug Resistance Genomic Island.Since 2004, extended-spectrum cephalosporin (ESC)-resistant Salmonella enterica serovar Typhimurium (S. Typhimurium) isolates have been detected from cattle in the northern major island of Japan, Hokkaido. Resistance to ESCs was found to be mediated by CMY-2 type +¦-lactamase among 22 epidemiologically unrelated isolates showing indistinguishable pulsed-field gel electrophoresis patterns. Southern blot analysis using I-CeuI-digested genomic DNA demonstrated that the CMY-2 +¦-lactamase gene (bla( ...201121709089
Molecular mechanism for eliminylation, a newly discovered post-translational modification.The newly discovered bacterial phosphothreonine lyases perform a post-translational modification of host cell signaling proteins through a novel catalytic mechanism that irreversibly removes the phosphate group from a phosphorylated threonine via +¦-elimination. This "eliminylation" reaction is shown by ab initio QM/MM studies to proceed via an E1cB-like pathway, in which the carbanion intermediate is stabilized by an enzyme oxyanion hole provided by Lys104 and Tyr158 of SpvC.201121710993
functional dissection of siie, a giant non-fimbrial adhesin of salmonella enterica.salmonella enterica deploys the giant non-fimbrial adhesin siie to adhere to the apical side of polarized epithelial cells. the establishment of close contact is a prerequisite for subsequent invasion mediated by translocation of effector proteins of the salmonella pathogenicity island 1 (spi1)-encoded type iii secretion system (t3ss). although siie is secreted into the culture medium, the adhesin is retained on the bacterial envelope in the phase of highest bacterial invasiveness. to dissect th ...201121729227
Refresh
firstprev
...41424344454647484950...
nextlast
Displaying items 4901 - 5000 of 11731