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flagella overexpression attenuates salmonella pathogenesis.flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. previous work showing appendage overexpression, referred to as attenuating gene expression (age), was found to enfeeble wild-type salmonella. thus, this approach was adapted to di ...201223056473
bioengineered nisin a derivatives with enhanced activity against both gram positive and gram negative pathogens.nisin is a bacteriocin widely utilized in more than 50 countries as a safe and natural antibacterial food preservative. it is the most extensively studied bacteriocin, having undergone decades of bioengineering with a view to improving function and physicochemical properties. the discovery of novel nisin variants with enhanced activity against clinical and foodborne pathogens has recently been described. we screened a randomized bank of nisin a producers and identified a variant with a serine to ...201223056510
antibiotic resistant salmonella and escherichia coli isolated from indigenous gallus domesticus in nairobi, kenya.to characterise and investigate antimicrobial resistance of esherichia coli and salmonella strains isolated from indigenous gallus gallus in a leading slaughterhouse/market outlet in nairobi-kenya.201023057283
a phosphotransferase system permease is a novel component of cadc signaling in salmonella enterica.in salmonella enterica serovar typhimurium, proteolytic cleavage of the membrane-bound transcriptional regulator cadc acts as a switch to activate genes of the lysine decarboxylase system in response to low ph and lysine signals. to identify the genetic factors required for the proteolytic activation of cadc, we performed genome-wide random mutagenesis. we show that a phosphotransferase system (pts) permease stm4538 acts as a positive modulator of cadc function. the transposon insertion in stm45 ...201323066934
immunological characterization of recombinant salmonella enterica serovar typhi flic protein expressed in escherichia coli.like any other enteric pathogen, salmonella also encounters acidic stress in the stomach as well as within the host macrophage milieu. however, the pathogen is reported to combat this stress through acid tolerance response (atr), expressing a number of genes and eventually the proteins. recently, an acid induced outer membrane phenotype encoded by flic gene in salmonella enterica serovar typhi has been identified. in the present study, flic gene was cloned to study its biological implications. t ...201223067582
humanized tlr4/md-2 mice reveal lps recognition differentially impacts susceptibility to yersinia pestis and salmonella enterica.although lipopolysaccharide (lps) stimulation through the toll-like receptor (tlr)-4/md-2 receptor complex activates host defense against gram-negative bacterial pathogens, how species-specific differences in lps recognition impact host defense remains undefined. herein, we establish how temperature dependent shifts in the lipid a of yersinia pestis lps that differentially impact recognition by mouse versus human tlr4/md-2 dictate infection susceptibility. when grown at 37°c, y. pestis lps is hy ...201223071439
inactivation of salmonella enterica on tomato stem scars by antimicrobial solutions and vacuum perfusion.a study was conducted to identify sanitizing solutions effective at inactivating ca. 5logcfu of salmonella enterica inoculated onto the stem scar of red round tomatoes during two-minute immersion treatments. sixty-three antimicrobial combinations were tested. vacuum perfusion was applied to tomatoes during selected treatments to promote infiltration of sanitizer into porous tomato stem scar tissue. red round tomatoes were inoculated to ca. 6.9logcfu/stem scar with a four-serovar composite of sal ...201223072692
behaviour of co-inoculated pathogenic and spoilage bacteria on poultry following several decontamination treatments.the potential of chemical decontaminants to cause harmful effects on human health is among the causes of the rejection of antimicrobial treatments for removing surface contamination from poultry carcasses in the european union. this study was undertaken to determine whether decontaminants might give a competitive advantage to pathogenic bacteria on poultry and involve a potential risk to consumer. a total of 144 chicken legs were co-inoculated with similar concentrations of pathogenic bacteria ( ...201223072701
silencing of vamp3 expression does not affect brucella melitensis infection in mouse macrophages.it has been proposed that intracellular pathogens may interfere with expression or function of proteins that mediate vesicular traffic in order to survive inside cells. brucella melitensis is an intracellular pathogen that evades phagosome-lysosome fusion, surviving in the so-called brucella-containing vacuoles (bcv). vesicle-associated membrane protein 3 (vamp3) is a v-snare protein that promotes the exocytosis of the proinflammatory cytokine tnf at the phagocytic cup when docking to its cognat ...201223076244
extremely drug-resistant salmonella enterica serovar senftenberg infections in patients in zambia.two cases of extremely drug-resistant salmonella enterica serovar senftenberg isolated from patients in zambia were investigated by utilizing mic determinations and whole-genome sequencing. the isolates were resistant to, and harbored genes toward, nine drug classes, including fluoroquinolones and extended-spectrum cephalosporins, contained two plasmid replicons, and differed by 93 single-nucleotide polymorphisms.201323077128
the pduq enzyme is an alcohol dehydrogenase used to recycle nad+ internally within the pdu microcompartment of salmonella enterica.salmonella enterica uses a bacterial microcompartment (mcp) for coenzyme b(12)-dependent 1,2-propanediol (1,2-pd) utilization (pdu). the pdu mcp consists of a protein shell that encapsulates enzymes and cofactors required for metabolizing 1,2-pd as a carbon and energy source. here we show that the pduq protein of s. enterica is an iron-dependent alcohol dehydrogenase used for 1,2-pd catabolism. pduq is also demonstrated to be a new component of the pdu mcp. in addition, a series of in vivo and i ...201223077559
characterization of curli a production on living bacterial surfaces by scanning probe microscopy.curli are adhesive surface fibers produced by many enterobacteriaceae, such as escherichia coli and salmonella enterica. they are implicated in bacterial attachment and invasion to epithelial cells. in this study, atomic force microscopy was used to determine the effects of curli on topology and mechanical properties of live e. coli cells. young's moduli of both curli-deficient and curli-overproducing mutants were significantly lower than that of their wild-type (wt) strain, while decay lengths ...201223083709
live oral typhoid vaccine salmonella typhi ty21a - a surrogate vaccine against non-typhoid salmonella?non-typhoid salmonella (nts) is a leading cause of food-borne illness with more than 90 million annual cases and an emerging antimicrobial resistance among the strains worldwide. paradoxically, no vaccines are available against these pathogens. numerous nts strains share surface o-antigens with salmonella enterica serotype typhi. as intestinal antibodies against o-antigens have proven protective against nts in animal experiments, it appears conceivable that the oral whole-cell typhoid vaccine, s ...201223084770
real-time evolution of new genes by innovation, amplification, and divergence.gene duplications allow evolution of genes with new functions. here, we describe the innovation-amplification-divergence (iad) model in which the new function appears before duplication and functionally distinct new genes evolve under continuous selection. one example fitting this model is a preexisting parental gene in salmonella enterica that has low levels of two distinct activities. this gene is amplified to a high copy number, and the amplified gene copies accumulate mutations that provide ...201223087246
genome expression analysis of nonproliferating intracellular salmonella enterica serovar typhimurium unravels an acid ph-dependent phop-phoq response essential for dormancy.genome-wide expression analyses have provided clues on how salmonella proliferates inside cultured macrophages and epithelial cells. however, in vivo studies show that salmonella does not replicate massively within host cells, leaving the underlying mechanisms of such growth control largely undefined. in vitro infection models based on fibroblasts or dendritic cells reveal limited proliferation of the pathogen, but it is presently unknown whether these phenomena reflect events occurring in vivo. ...201323090959
polyphasic characterization of salmonella enteritidis isolates on persistently contaminated layer farms during the implementation of a national control program with obligatory vaccination: a longitudinal study.since 2007, a national salmonella control program including obligatory vaccination has been ongoing in belgium. in this context, the aim of the present study was to investigate the diversity of salmonella enterica serovar enteritidis isolates on 5 persistently contaminated belgian layer farms and to examine the potential sources and transmission routes of salmonella enteritidis contamination on the farms during successive laying rounds. a collection of 346 salmonella isolates originating from th ...201223091125
optimized culturing and nucleic acid-based methods for the detection of salmonella enterica in poultry environments.the main objective of this trial was to set up a series of assays following quantified inoculation of salmonella samples in 2 initial enrichment methods to ultimately determine the most effective and fastest detection method for recovery of salmonella in a poultry environment matrix. samples were randomly split into 2 different containers containing either buffered peptone water (bpw) + yeast extract, or tetrathionate broth (tt) with added iodine and brilliant green solution 0.1%. a frozen stock ...201223091129
intestinal epithelial responses to salmonella enterica serovar enteritidis: effects on intestinal permeability and ion transport.salmonella infection of chickens that leads to potential human foodborne salmonellosis continues to be a major concern. chickens serve as carriers but, in contrast to humans, rarely show any clinical signs including diarrhea. the present investigations aimed to elucidate whether the absence of diarrhea during acute salmonella enterica serovar enteritidis (salmonella enteritidis) infection may be linked to specific changes in the electrophysiological properties of the chicken gut. immediately aft ...201223091155
use of bioluminescence mutant screening for identification of edwardsiella ictaluri genes involved in channel catfish (ictalurus punctatus) skin colonization.initial invasion of the host is the first and vital part of any infection process. we have demonstrated that edwardsiella ictaluri is capable of colonizing and penetrating catfish skin. therefore, a mutant library was constructed by random insertion of the mar2xt7 transposon into the chromosome of e. ictaluri harboring the bioluminescence plasmid pakgfplux1. this library was then screened through a series of three consecutive challenges for mutants showing a decreased ability to colonize the cat ...201323092811
characterization of chicken spleen transcriptome after infection with salmonella enterica serovar enteritidis.in this study we were interested in identification of new markers of chicken response to salmonella enteritidis infection. to reach this aim, gene expression in the spleens of naive chickens and those intravenously infected with s. enteritidis with or without previous oral vaccination was determined by 454 pyrosequencing of splenic mrna/cdna. forty genes with increased expression at the level of transcription were identified. the most inducible genes encoded avidin (avd), extracellular fatty aci ...201223094107
the population structure of salmonella enterica enteritidis in iran analyzed by multiple-locus variable-number tandem repeat analysis.salmonella enterica enteritidis is the most frequent etiological agent of salmonellosis in humans and poultry. to understand the genetic diversity of s. enteritidis in iran, we examined 69 chicken isolates from 18 broiler farms and six non-epidemic human isolates from six geographically distant provinces by multi-locus variable-number tandem repeat analysis (mlva). among se2, se3, se5, se7, se8, sentr4, and sentr7, only se5 with four and sentr7 with two alleles, respectively, proved variable giv ...201323096767
exchangeability of the flagellin (flic) and the cap protein (flid) among different species in flagellar assembly.flagellar filament self-assembles from the component protein, flagellin or flic, with the aid of the capping protein, hap2 or flid. depending on the helical parameters of filaments, flagella from various species are divided into three groups, family i, ii, and iii. each family coincides with the traditional classification of flagella, peritrichous flagella, polar flagella, and lateral flagella, respectively. to elucidate the physico-chemical properties of flagellin to separate families, we chose ...201323097231
impacts of salmonella enteritidis infection on liver transcriptome in broilers.salmonella enterica serovar enteritidis is an enteric bacterium that can contaminate chicken eggs and meat, resulting in production losses and consumer illness. to provide insight into the systemic metabolic effects of s. enteritidis infection, liver samples were harvested 10-days postinfection from broiler hens. hepatic global gene expression levels were assessed using a chicken 44k agilent microarray. forty-four genes were differentially expressed at a significance level of q value < 0.05. one ...201323097340
evaluation of a simple blood culture amplification and antigen detection method for diagnosis of salmonella enterica serovar typhi bacteremia.in most areas where typhoid is endemic, laboratory diagnosis is not possible due to the lack of appropriate facilities. we investigated whether the combination of blood culture amplification of salmonella enterica serovar typhi with an s. typhi antigen rapid diagnostic test (rdt) could be an accurate and inexpensive tool for the accelerated diagnosis of patients with acute typhoid in laos. for a panel of 23 gram-negative reference pathogens, the standard diagnostics (catalog no. 15fk20; kyonggi- ...201323100346
a tollgate for typhoid.humans are uniquely susceptible to typhoid fever caused by infection with salmonella enterica serovar typhi. mathur et al. now report that mice lacking toll-like receptor 11, which is absent in humans, can be lethally infected with s. typhi, a breakthrough that promises to speed the development of better vaccines.201223101620
anthranilate phosphoribosyl transferase (trpd) generates phosphoribosylamine for thiamine synthesis from enamines and phosphoribosyl pyrophosphate.anthranilate phosphoribosyl transferase (trpd) has been well characterized for its role in the tryptophan biosynthetic pathway. here, we characterized a new reaction catalyzed by trpd that resulted in the formation of the purine/thiamine intermediate metabolite phosphoribosylamine (pra). the data showed that 4- and 5-carbon enamines served as substrates for trpd, and the reaction product was predicted to be a phosphoribosyl-enamine adduct. isotopic labeling data indicated that the trpd reaction ...201323101964
is nalidixic acid screening still valid for the detection of reduced susceptibility of fluoroquinolone with salmonella typhi?considering the limitations of screening with nalidixic acid to detect reduced susceptibility to fluoroquinolones of salmonella enterica serovar typhi (s.typhi) strains, we evaluated the use of a 30 µg nalidixic acid disc screening method in pakistan.201223103891
the salmonella transcriptome in lettuce and cilantro soft rot reveals a niche overlap with the animal host intestine.fresh vegetables have been recurrently associated with salmonellosis outbreaks, and salmonella contamination of retail produce has been correlated positively with the presence of soft rot disease. we observed that population sizes of salmonella enterica serovar typhimurium sl1344 increased 56-fold when inoculated alone onto cilantro leaves, versus 2,884-fold when coinoculated with dickeya dadantii, a prevalent pathogen that macerates plant tissue. a similar trend in s. enterica populations was o ...201323104408
immunological evaluation of vi capsular polysaccharide of salmonella enterica subsp. typhi vaccine by serum bactericidal assay.salmonella enterica subsp. typhi (s. typhi) vi antigen capsular polysaccharide (vi-cps) is a licensed vaccine against typhoid fever. as there is no animal model for s. typhi fever to evaluate the protective efficacy of the vi-cps vaccine, a serum bactericidal assay (sba) is the recommended 'gold standard' to evaluate its potency. vi-cps was extracted from s. typhi ty6s (csbpi-b191) using a modified gotschlich method. purified vi-cps (50 µg) was injected intramuscularly into three groups of five ...201323105026
draft genome sequence of salmonella enterica serovar typhimurium st1660/06, a multidrug-resistant clinical strain isolated from a diarrheic patient.salmonella enterica serovar typhimurium is one of the most prevalent serovars of salmonella that causes human gastroenteritis. here, we report the draft genome sequence of the s. typhimurium multidrug-resistant strain st1660/06. comparative genomic analysis unveiled three strain-specific genomic islands that potentially confer the multidrug resistance and virulence of the strain.201223105062
synthesis and anti-microbial potencies of 1-(2-hydroxyethyl)-3-alkylimidazolium chloride ionic liquids: microbial viabilities at different ionic liquids concentrations.three 1-(2-hydroxyethyl)-3-alkylimidazolium chloride room temperature ionic liquids (ils) [2ohimc(n)][cl]; (n=0, 1, 4) have been synthesized from the appropriate imidazole precursors and characterized by ir and nmr spectroscopies and elemental analysis. their anti-microbial activities were investigated using the well-diffusion method. the viabilities of escherichia coli, aeromonas hydrophila, listeria monocytogenes and salmonella enterica as a function of il concentrations were studied. the mini ...201323107478
porcine circovirus type 2 (pcv2) vaccination reduces pcv2 in a pcv2 and salmonella enterica serovar choleraesuis coinfection model.we previously reported that prior porcine circovirus type 2 (pcv2) infection potentiates the severity of clinical signs, lung lesions, and fecal shedding and tissue dissemination of salmonella enterica serovar choleraesuis in infected pigs. here, we evaluated whether pcv2 vaccination is effective in reducing fecal shedding and tissue dissemination of s. choleraesuis and improving clinical signs associated with pcv2 and s. choleraesuis infection in 15 cesarean-derived, colostrum-deprived pigs ran ...201323107657
manipulation of innate immunity by a bacterial secreted peptide: lantibiotic nisin z is selectively immunomodulatory.innate immunity is triggered by a variety of bacterial molecules, resulting in both protective and potentially harmful pro-inflammatory responses. further, innate immunity also provides a mechanism for the maintenance of homeostasis between the host immune system and symbiotic or non-pathogenic microorganisms. however, the bacterial factors that mediate these protective effects have been incompletely defined. here, it was demonstrated that the lantiobiotic nisin z is able to modulate host immune ...201323109507
detection of non-pcr amplified s. enteritidis genomic dna from food matrices using a gold-nanoparticle dna biosensor: a proof-of-concept study.bacterial pathogens pose an increasing food safety and bioterrorism concern. current dna detection methods utilizing sensitive nanotechnology and biosensors have shown excellent detection, but require expensive and time-consuming polymerase chain reaction (pcr) to amplify dna targets; thus, a faster, more economical method is still essential. in this proof-of-concept study, we investigated the ability of a gold nanoparticle-dna (aunp-dna) biosensor to detect non-pcr amplified genomic salmonella ...201223112611
increased susceptibility of melanin-concentrating hormone-deficient mice to infection with salmonella enterica serovar typhimurium.melanin-concentrating hormone (mch) was initially identified in mammals as a hypothalamic neuropeptide regulating appetite and energy balance. however, the wide distribution of mch receptors in peripheral tissues suggests additional functions for mch which remain largely unknown. we have previously reported that mice lacking mch develop attenuated intestinal inflammation when exposed to clostridium difficile toxin a. to further characterize the role of mch in host defense mechanisms against inte ...201323115043
bloodstream infection among children presenting to a general hospital outpatient clinic in urban nepal.there are limited data on the etiology and characteristics of bloodstream infections in children presenting in hospital outpatient settings in south asia. previous studies in nepal have highlighted the importance of murine typhus as a cause of febrile illness in adults and enteric fever as a leading bacterial cause of fever among children admitted to hospital.201223115652
composition and antimicrobial activity of the skin peptidome of russian brown frog rana temporaria.a nano-hplc-esi-orbitrap study involving hcd and etd spectra has been carried out to clarify the composition of the skin peptidome of brown russian frogs rana temporaria. this approach allowed determinantion of 76 individual peptides, increasing 3-fold the identified portion of the peptidome in comparison to that obtained earlier with fticr ms. a search for the new bradykinin related peptides (brps) was carried out by reconstructing mass chromatograms based on the ion current of characteristic b ...201223121565
inactivation of salmonella enterica serovar typhimurium on fresh produce by cold atmospheric gas plasma technology.cold atmospheric gas plasma treatment (cap) is an alternative approach for the decontamination of fresh and minimally processed food. in this study, the effects of growth phase, growth temperature and chemical treatment regime on the inactivation of salmonella enterica serovar typhimurium (s. typhimurium) by nitrogen cap were examined. furthermore, the efficacy of cap treatment for decontaminating lettuce and strawberry surfaces and potato tissue inoculated with s. typhimurium was evaluated. it ...201323122497
enteric fever in cambodian children is dominated by multidrug-resistant h58 salmonella enterica serovar typhi with intermediate susceptibility to ciprofloxacin.infections with salmonella enterica serovar typhi isolates that are multidrug resistant (mdr: resistant to chloramphenicol, ampicillin, trimethoprim-sulphamethoxazole) with intermediate ciprofloxacin susceptibility are widespread in asia but there is little information from cambodia. we studied invasive salmonellosis in children at a paediatric hospital in siem reap, cambodia. between 2007 and 2011 salmonella was isolated from a blood culture in 162 children. there were 151 children with enteric ...201223122884
persistence and leaching potential of microorganisms and mineral n in animal manure applied to intact soil columns.pathogens may reach agricultural soils through application of animal manure and thereby pose a risk of contaminating crops as well as surface and groundwater. treatment and handling of manure for improved nutrient and odor management may also influence the amount and fate of manure-borne pathogens in the soil. a study was conducted to investigate the leaching potentials of a phage (salmonella enterica serovar typhimurium bacteriophage 28b) and two bacteria, escherichia coli and enterococcus spec ...201323124240
a novel synthetic peptide from a tomato defensin exhibits antibacterial activities against helicobacter pylori.defensins are a class of cysteine-rich proteins, which exert broad spectrum antimicrobial activity. in this work, we used a bioinformatic approach to identify putative defensins in the tomato genome. fifteen proteins had a mature peptide that includes the well-conserved tetradisulfide array. we selected a representative member of the tomato defensin family; we chemically synthesized its γ-motif and tested its antimicrobial activity. here, we demonstrate that the synthetic peptide exhibits potent ...201223124812
epidemic of salmonellosis in passerine birds in switzerland with spillover to domestic cats.a die-off of passerine birds, mostly eurasian siskins (carduelis spinus), occurred in multiple areas of switzerland between february and march 2010. several of the dead birds were submitted for full necropsy. bacteriological examination was carried out on multiple tissues of each bird. at gross examination, common findings were light-tan nodules, 1 to 4 mm in diameter, scattered through the esophagus/crop. histologically, a necroulcerative transmural esophagitis/ingluvitis was observed. bacteria ...201323125146
carbon and clay nanoparticles induce minimal stress responses in gram negative bacteria and eukaryotic fish cells.we investigated in vitro the potential mutagenic and toxic effects of two clay-based nanoparticles, cloisite® na(+) (cloisite) and halloysite; and multi-walled carbon nanotubes (mwcnt), commonly used in the polymer composite industry. using the ames test, the three nanoparticles did not have a true mutagenic effect, although growth of salmonella enterica var. typhimurium (s.typhimurium) was diminished at higher nanoparticle concentrations. we investigated the impact of nanoparticles on escherich ...201423125163
salmonella enterica serotype bovismorbificans, a new host for ctx-m-9. 201323127480
the effect of environmental pollutants and food processing on the development of antibiotic resistance.the purpose of this study was to determine how various compounds known to be positive mutagens, contribute to the development of mutations leading to ciprofloxacin resistance in salmonella enterica subsp. enterica serotype typhimurium. the molecular mechanism of ciprofloxacin resistance in treated strains was investigated.201423128813
polythiophene synthesis coupled to quartz crystal microbalance and raman spectroscopy for detecting bacteria.a simple electrochemical procedure was used for the synthesis of a polythiophene containing para-benzenesulfonyl chloride groups. the obtained polymer was shown to be very reactive and directly able to covalently bind nucleophile biomolecules. protein a and a specific antibody were then successively immobilized on the conductive polymer through a covalent bonding of protein a with the as-prepared linker for bacteria trapping purpose. all reactions were controlled in situ by cyclic voltammetry, q ...201223129343
immunological changes at point-of-lay increase susceptibility to salmonella enterica serovar enteritidis infection in vaccinated chickens.chicken eggs are the main source of human salmonella enterica serovar enteritidis infection. s. enteritidis infects the oviduct and ovary of the chicken leading to infection of developing eggs. therefore, control in poultry production is a major public health priority. vaccination of hens has proved successful in control strategies in united kingdom leading to a 70% drop in human cases since introduced. however, as hens reach sexual maturity they become immunosuppressed and it has been postulate ...201223133568
perturbations in histidine biosynthesis uncover robustness in the metabolic network of salmonella enterica.phosphoribosylamine (pra) is an intermediate in the biosynthetic pathway that is common to thiamine and purines. glutamine phosphoribosyl pyrophosphate (prpp) amidotransferase is the product of the purf gene in salmonella enterica and catalyzes the synthesis of pra from prpp and glutamine. strains lacking purf require exogenous addition of purines for growth. however, under some growth conditions or with specific secondary mutations these strains grow in the absence of exogenous thiamine. mutant ...201223133571
genetic analysis of non-hydrogen sulfide-producing salmonella enterica serovar typhimurium and s. enterica serovar infantis isolates in japan.whole-genome sequencing of non-h(2)s-producing salmonella enterica serovar typhimurium and s. enterica serovar infantis isolates from poultry meat revealed a nonsense mutation in the phsa thiosulfate reductase gene and carriage of a cmy-2 β-lactamase. the lack of production of h(2)s might lead to the incorrect identification of s. enterica isolates carrying antimicrobial resistance genes.201323135931
tissue dyslipidemia in salmonella-infected rats treated with amoxillin and pefloxacin.this study investigated the effects of salmonella infection and its chemotherapy on lipid metabolism in tissues of rats infected orally with salmonella typhimurium and treated intraperitoneally with pefloxacin and amoxillin.201223137290
oligosaccharide structure determines prebiotic role of β-galactomannan against salmonella enterica ser. typhimurium in vitro.prebiotics and probiotics are considered natural alternatives to dietary antibiotics in animal production. plant extracts and yeast cell walls are mannose-rich products that can be used as substrate for adhesion of gram-negative bacteria. we assessed whether the structure of these saccharides is relevant to develop their role as prebiotics and therefore, their suitability to be used as alternatives to antibiotics to prevent intestinal infections in pigs. the prebiotic functionality of β-galactom ...201523137964
phenotypic and genotypic features of antibiotic resistance in salmonella enterica isolated from chicken meat and chicken and quail carcasses.one hundred and twenty-three salmonella enterica isolated in italy from chicken meat and carcasses and from quail carcasses were analyzed to determine their levels of antibiotic resistance using antibiograms (phenotypic method) and pcr amplification of antimicrobial resistance-associated genes (genotypic method). the isolates were screened for the ability to grow in the presence of antibiotics (ampicillin, gentamicin, sulfamethoxazole and tetracycline) and for the presence of the following genes ...201223141641
adhesion and splash dispersal of salmonella enterica typhimurium on tomato leaflets: effects of rdar morphotype and trichome density.salmonella enterica strains with rdar (red dry and rough) and saw (smooth and white) morphotypes have previously been associated with tomato outbreaks but the dispersal mechanisms of these morphotypes are still poorly understood. in this study, salmonella adhesion was distinguished from attachment by comparing different contact periods. initial adhesion of rdar and saw morphotypes of salmonella was compared in relation to tomato plants with different leaf trichome densities. trichome densities w ...201223141646
immunogenicity of salmonella enterica serovar enteritidis virulence protein, invh, and cross-reactivity of its antisera with salmonella strains.acellular vaccines containing bacterial immunodominant components such as surface proteins may be potent alternatives to live attenuated vaccines in order to reduce salmonellosis risk to human health. invh gene, an important part of needle complex in type three secretion system (ttss) plays important role in efficient bacterial adherence and entry into epithelial cells. in this work we hypothesize that use of a 15 kda recombinant invh as salmonella enterica serovar enteritidis surface protein co ...201323141708
a scalable method for o-antigen purification applied to various salmonella serovars.the surface lipopolysaccharide of gram-negative bacteria is both a virulence factor and a b cell antigen. antibodies against o-antigen of lipopolysaccharide may confer protection against infection, and o-antigen conjugates have been designed against multiple pathogens. here, we describe a simplified methodology for extraction and purification of the o-antigen core portion of salmonella lipopolysaccharide, suitable for large-scale production. lipopolysaccharide extraction and delipidation are per ...201323142430
influence of salmonella enterica serovar enteritidis infection on the development of the cecum microbiota in newly hatched chicks.terminal restriction fragment length polymorphism and quantitative pcr showed that the cecal microbiota of chicks up to the age of 21 days was dominated by representatives of the orders enterobacteriales, clostridiales, and lactobacillales. salmonella enterica serovar enteritidis infection caused the greatest changes in the gut microbiota when 1-day-old chicks were infected, compared with the infection of 4- and 16-day-old chicks.201323144133
landscape and meteorological factors affecting prevalence of three food-borne pathogens in fruit and vegetable farms.produce-related outbreaks have been traced back to the preharvest environment. a longitudinal study was conducted on five farms in new york state to characterize the prevalence, persistence, and diversity of food-borne pathogens in fresh produce fields and to determine landscape and meteorological factors that predict their presence. produce fields were sampled four times per year for 2 years. a total of 588 samples were analyzed for listeria monocytogenes, salmonella, and shiga toxin-producing ...201323144137
structural insight into the clostridium difficile ethanolamine utilisation microcompartment.bacterial microcompartments form a protective proteinaceous barrier around metabolic enzymes that process unstable or toxic chemical intermediates. the genome of the virulent, multidrug-resistant clostridium difficile 630 strain contains an operon, eut, encoding a bacterial microcompartment with genes for the breakdown of ethanolamine and its utilisation as a source of reduced nitrogen and carbon. the c. difficile eut operon displays regulatory genetic elements and protein encoding regions in co ...201223144756
o:2-crm(197) conjugates against salmonella paratyphi a.enteric fevers remain a common and serious disease, affecting mainly children and adolescents in developing countries. salmonella enterica serovar typhi was believed to cause most enteric fever episodes, but several recent reports have shown an increasing incidence of s. paratyphi a, encouraging the development of a bivalent vaccine to protect against both serovars, especially considering that at present there is no vaccine against s. paratyphi a. the o-specific polysaccharide (o:2) of s. paraty ...201223144798
type 1 interferon-associated necroptosis: a novel mechanism for salmonella enterica typhimurium to induce macrophage death. 201223147719
first detection of oqxab in salmonella spp. isolated from food.food-borne salmonellosis is an important public health problem worldwide and the second leading cause of food-borne illnesses in hong kong. in this study, the prevalence and antimicrobial resistance of salmonella in meat products in hong kong were determined. interestingly, a plasmid-mediated quinolone resistance (pmqr) gene combination, oqxab, which mediates resistance to nalidixic acid, chloramphenicol, and olaquindox, was for the first time detectable on the chromosomes of two salmonella ente ...201323147728
structural insights into the mechanism of four-coordinate cob(ii)alamin formation in the active site of the salmonella enterica atp:co(i)rrinoid adenosyltransferase enzyme: critical role of residues phe91 and trp93.atp:co(i)rrinoid adenosyltransferases (acats) are enzymes that catalyze the formation of adenosylcobalamin (adocbl, coenzyme b(12)) from cobalamin and atp. there are three families of acats, namely, coba, eutt, and pduo. in salmonella enterica, coba is the housekeeping enzyme that is required for de novo adocbl synthesis and for salvaging incomplete precursors and cobalamin from the environment. here, we report the crystal structure of coba in complex with atp, four-coordinate cobalamin, and fiv ...201223148601
systemic flagellin immunization stimulates mucosal cd103+ dendritic cells and drives foxp3+ regulatory t cell and iga responses in the mesenteric lymph node.mucosal immunity is poorly activated after systemic immunization with protein ags. nevertheless, induction of mucosal immunity in such a manner would be an attractive and simple way to overcome the intrinsic difficulties in delivering ag to such sites. flagellin from salmonella enterica serovar typhimurium (flic) can impact markedly on host immunity, in part via its recognition by tlr5. in this study, we show that systemic immunization with soluble flic (sflic) drives distinct immune responses c ...201223152564
neutrophil elastase alters the murine gut microbiota resulting in enhanced salmonella colonization.the intestinal microbiota has been found to play a central role in the colonization of salmonella enterica serovar typhimurium in the gastrointestinal tract. in this study, we present a novel process through which salmonella benefit from inflammatory induced changes in the microbiota in order to facilitate disease. we show that salmonella infection in mice causes recruitment of neutrophils to the gut lumen, resulting in significant changes in the composition of the intestinal microbiota. this oc ...201223155475
[pyopneumothorax caused by salmonella choleraesuis: a case report and review of the literature].to improve understanding of the clinical features, diagnosis and treatment of pyopneumothorax caused by salmonella choleraesuis.201223158072
m cell differentiation: distinct lineage or phenotypic transition? salmonella provides answers.whether m cells arise from a distinct lineage or result from phenotypic transition is a matter of debate. in this issue of cell host & microbe, tahoun et al. (2012) provide evidence that sopb, a virulence factor of salmonella enterica serovar typhimurium, can induce phenotypic transition of lymphoid follicle-associated enterocytes into m cells.201223159049
deletion of invh gene in salmonella enterica serovar typhimurium limits the secretion of sip effector proteins.the type-iii secretion system-i (t3ss-i) of salmonella enterica serovar typhimurium (s. typhimurium) is an essential component to mediate active invasion and subsequent inflammation in genetically susceptible c57bl/6 mice. s. typhimurium translocates its effector proteins through salmonella pathogenicity island-i (spi-i) encoded t3ss-i needle complex. this study focuses on invh gene of s. typhimurium, which plays an active role in spi-i mediated effector protein translocation. the deletion of in ...201323159244
salmonella inhibits retrograde trafficking of mannose-6-phosphate receptors and lysosome function.salmonella enterica is an intracellular bacterial pathogen that replicates within membrane-bound vacuoles through the action of effector proteins translocated into host cells. salmonella vacuoles have characteristics of lysosomes but are reduced in hydrolytic enzymes transported by mannose-6-phosphate receptors (mprs). we found that the effector sifa subverted rab9-dependent retrograde trafficking of mprs, thereby attenuating lysosome function. this required binding of sifa to its host cell targ ...201223162002
comparative study of the protective capacity against salmonella infection between probiotic and nonprobiotic lactobacilli.to investigate the immunoprotective ability of three lactobacilli strains against salmonella enterica serovar typhimurium in a mouse model. to identify the probiotic properties involved in the protection against infection caused by this pathogen.201323163296
glycoengineering of host mimicking type-2 lacnac polymers and lewis x antigens on bacterial cell surfaces.bacterial carbohydrate structures play a central role in mediating a variety of host-pathogen interactions. glycans can either elicit protective immune response or lead to escape of immune surveillance by mimicking host structures. lipopolysaccharide (lps), a major component on the surface of gram-negative bacteria, is composed of a lipid a-core and the o-antigen polysaccharide. pathogens like neisseria meningitidis expose a lipooligosaccharide (los), which outermost glycans mimick mammalian epi ...201323163552
expression of hila in response to mild acid stress in salmonella enterica is serovar and strain dependent.salmonella enterica is the leading cause of foodborne illness with poultry and poultry products being primary sources of infection. the 2 most common s. enterica serovars associated with human infection are typhimurium and enteritidis. however, kentucky and heidelburg and the 2 most prevalent serovars isolated from poultry environments. given the prevalence of other serovars in poultry products and environments, research is needed to understand virulence modulation in response to stress in serov ...201223163946
solar inactivation of four salmonella serovars in fresh and marine waters.sunlight-mediated disinfection of water is of interest to both the drinking and recreational water quality community of researchers due to its potential to reduce microbial contamination and waterborne illness. photo-inactivation of enteric bacteria has primarily been investigated using escherichia coli and laboratory strains of model bacteria. the present study sought to document the photo-inactivation of environmental isolates of salmonella in filter-sterilized natural seawater and freshwater ...201223165707
the "decline and fall" of nontyphoidal salmonella in the united kingdom.remarkable changes in the epidemiology of human nontyphoidal salmonellosis have occurred in the united kingdom over the last century. between 1981 and 1991, the incidence of nontyphoidal salmonellosis in the united kingdom rose by >170%, driven primarily by an epidemic of salmonella enterica subspecies enterica serovar enteritidis phage type (pt) 4, which peaked in 1993. measures introduced to control this epidemic included legislation, food safety advice, and an industry-led vaccination program ...201323166188
complete genome sequence of the novel lytic avian pathogenic coliphage nj01.bacteriophages of the c3 morphotype, characterized by very long heads that exceed their width several times, are extremely rare among the podoviridae family members and constitute only 0.5% of over 5,500 phages that have been examined by the electron microscope (h. w. ackermann, arch. virol. 152:227-243, 2007; h. w. ackermann, arch. virol. 146:843-857, 2001). to date, among those phages proven to be c3, only coliphage phieco32, lactococcus phage ksy1, vibrio phage 71a-6, and salmonella enterica ...201223166270
an altered immune response, but not individual cationic antimicrobial peptides, is associated with the oral attenuation of ara4n-deficient salmonella enterica serovar typhimurium in mice.salmonella enterica serovar typhimurium (s. typhimurium) uses two-component regulatory systems (tcrs) to respond to stimuli in the local microenvironment. upon infection, the salmonella tcrss phop-phoq (phopq) and pmra-pmrb (pmrab) are activated by environmental signals in the intestinal lumen and within host cells. tcrs-mediated gene expression results in lipopolysaccharide (lps) modification and cationic antimicrobial peptide resistance. the pmra-regulated pmrhfijklm operon mediates 4-amino-4- ...201223166721
salmonella typhi in the democratic republic of the congo: fluoroquinolone decreased susceptibility on the rise.drug resistance of salmonella enterica serovar typhi (salmonella typhi) to first-line antibiotics is emerging in central africa. although increased use of fluoroquinolones is associated with spread of resistance, salmonella typhi with decreased ciprofloxacin susceptibility (dcs) has rarely been reported in central africa.201223166855
salmonella serotype diversity and seasonality in urban and rural streams.to investigate the prevalence, seasonality and genetic diversity of salmonella enterica serotypes, particularly those of human and veterinary health significance, in urban and rural streams.201323167768
multistate outbreak of salmonella serotype bovismorbificans infections associated with hummus and tahini--united states, 2011.on september 27, 2011, three clinical isolates of salmonella enterica serotype bovismorbificans with indistinguishable pulsed-field gel electrophoresis (pfge) patterns were identified by the district of columbia public health laboratory (phl). human infection with s. bovismorbificans is rare in the united states. through query of pulsenet, the national molecular subtyping network for foodborne disease surveillance, six additional cases with indistinguishable pfge patterns were identified in thre ...201223169315
multiplicity of salmonella entry mechanisms, a new paradigm for salmonella pathogenesis.the salmonella enterica species includes about 2600 diverse serotypes, most of which cause a wide range of food- and water-borne diseases ranging from self-limiting gastroenteritis to typhoid fever in both humans and animals. moreover, some serotypes are restricted to a few animal species, whereas other serotypes are able to infect plants as well as cold- and warm-blooded animals. an essential feature of the pathogenicity of salmonella is its capacity to cross a number of barriers requiring inva ...201223170225
the copper supply pathway to a salmonella cu,zn-superoxide dismutase (sodcii) involves p(1b)-type atpase copper efflux and periplasmic cuep.periplasmic cu,zn-superoxide dismutases (cu,zn-sods) are implicated in bacterial virulence. it has been proposed that some bacterial p(1b)-type atpases supply copper to periplasmic cupro-proteins and such transporters have also been implicated in virulence. here we show that either of two p(1b)-type atpases, copa or golt, is needed to activate a periplasmic cu,zn-sod (sodcii) in salmonella enterica serovar typhimurium. a δcopa/δgolt mutant accumulates inactive zn-sodcii which can be activated by ...201323171030
occurrence of pathogens in wild rodents caught on swedish pig and chicken farms.a total of 207 wild rodents were caught on nine pig farms, five chicken farms and five non-farm locations in sweden and surveyed for a selection of bacteria, parasites and viruses. lawsonia intracellularia and pathogenic yersinia enterocolitica were only detected in rodents on pig farms (9% and 8% prevalence, respectively) which indicate that these agents are more likely to be transmitted to rodents from pigs or the environment on infected farms. brachyspira hyodysenteriae (1%), brachyspira inte ...201323174339
strain variability of the biofilm-forming ability of salmonella enterica under various environmental conditions.the biofilm-forming ability of 60 salmonella enterica strains was assessed at different ph values (3.8-7.0), nacl concentrations (0.5-8.0%) and temperatures (4-37°c). a total of 4320 biofilm formation tests (60 strains×12 different environmental conditions×6 replicates) were carried out. biofilm formation was evaluated in tryptone soy broth after 48h of incubation in polystyrene microtiter plates using crystal violet staining, and its quantification was based on the difference between the optica ...201223177057
phenotypic and genetic traits of salmonella enterica subsp. serovar typhimurium strains causing salmonellosis foci in rabbit farms from southern italy in 1999-2003.in this study, we characterised the salmonella typhimurium strains responsible for four outbreaks which occurred in distinct rabbit farms (southern italy) from 1999 to 2003. strains were typed by pulsed field gel electrophoresis (pfge) and the genetic basis of antimicrobial resistance was established. a major group of clonally related isolates, pulsotype stymxb.0061, accounted for three of the salmonellosis foci. strains were resistant to streptomycin, chloramphenicol, tetracycline, ampicillin a ...201323178046
failure of oral antibiotic therapy, including azithromycin, in the treatment of a recurrent breast abscess caused by salmonella enterica serotype paratyphi a.we report a case of recurrent, multifocal salmonella enterica serotype paratyphi a breast abscesses, resistant to ciprofloxacin, which relapsed despite surgery, aspiration and multiple courses of antibiotics, including co-trimoxazole and azithromycin. the patient was cured after a prolonged course of intravenous ceftriaxone.201223182142
molecular characterization of antibiotic-resistant bacteria in contaminated chicken meat sold at supermarkets in bangkok, thailand.we assessed contamination by antibiotic-resistant bacteria in chicken meat obtained from supermarkets in bangkok, thailand. the prevalence of salmonella enterica and escherichia coli was 18.7% (14/75) and 53% (106/200), respectively. most probable number (mpn) analysis showed that 56.7% of the samples (34/60) were in violation of the limit of allowable coliform bacteria in chicken meat, for which the maximum is 46,000 mpn/g. multidrug-resistant phenotypes of both s. enterica and e. coli were fou ...201223183206
extended-spectrum β-lactamase- and ampc β-lactamase-producing salmonella enterica strains isolated from domestic retail chicken meat from 2006 to 2011. 201223183214
salmonella enterica serovar typhi plasmid pr st98 -mediated inhibition of autophagy promotes bacterial survival in infected fibroblasts.pr (st98) is a chimeric plasmid isolated from salmonella enterica serovar typhi (s. typhi) and mediates both drug-resistance and virulence of s. typhi. autophagy has been recently reported as an important component of the innate immune response against intracellular pathogen. in this study, we investigated the effect of pr (st98) on cellular autophagy, apoptosis and bacterial survival in infected fibroblasts. s. typhi strain st 8 carrying pr (st98) , salmonella typhimurium strain sr-11 carrying ...201223183467
interferon-γ- and glucocorticoid-mediated pathways synergize to enhance death of cd4(+) cd8(+) thymocytes during salmonella enterica serovar typhimurium infection.thymic atrophy is known to occur during infections; however, there is limited understanding of its causes and of the cross-talk between different pathways. this study investigates mechanisms involved in thymic atrophy during a model of oral infection by salmonella enterica serovar typhimurium (s. typhimurium). significant death of cd4(+) cd8(+) thymocytes, but not of single-positive thymocytes or peripheral lymphocytes, is observed at later stages during infection with live, but not heat-killed, ...201323186527
chip-seq and transcriptome analysis of the ompr regulon of salmonella enterica serovars typhi and typhimurium reveals accessory genes implicated in host colonization.ompr is a multifunctional dna binding regulator with orthologues in many enteric bacteria that exhibits classical regulator activity as well as nucleoid-associated protein-like characteristics. in the enteric pathogen salmonella enterica, using chromatin immunoprecipitation of ompr:flag and nucleotide sequencing, 43 putative ompr binding sites were identified in s. enterica serovar typhi, 22 of which were associated with ompr-regulated genes. mutation of a sequence motif (tgtwacaw) that was asso ...201323190111
immunological characterization of a gida mutant strain of salmonella for potential use in a live-attenuated vaccine.salmonella is often associated with gastrointestinal disease outbreaks in humans throughout the world due to the consumption of contaminated food. our previous studies have shown that deletion of glucose-inhibited division gene (gida) significantly attenuated salmonella enterica serovar typhimurium (stm) virulence in both in vitro and in vivo models of infection. most importantly, immunization with the gida mutant protected mice from a lethal dose challenge of wild-type stm. in this study, we fu ...201223194372
genomic paradigms for food-borne enteric pathogen analysis at the usfda: case studies highlighting method utility, integration and resolution.modern risk control and food safety practices involving food-borne bacterial pathogens are benefiting from new genomic technologies for rapid, yet highly specific, strain characterisations. within the united states food and drug administration (usfda) center for food safety and applied nutrition (cfsan), optical genome mapping and dna microarray genotyping have been used for several years to quickly assess genomic architecture and gene content, respectively, for outbreak strain subtyping and to ...201323199033
multiplex fiber optic biosensor for detection of listeria monocytogenes, escherichia coli o157:h7 and salmonella enterica from ready-to-eat meat samples.listeria monocytogenes, escherichia coli o157:h7 and salmonella enterica are the most common foodborne bacterial pathogens and are responsible for many outbreaks. therefore, multiplex detection of these three using a single assay platform is highly desirable. the objective was to develop and optimize a fiber optic sensor for simultaneous detection of these three from food. the streptavidin coated optical waveguides were immobilized with biotinylated polyclonal antibodies and exposed to the bacte ...201323200648
comparison of heat stress responses of immobilized and planktonic salmonella enterica serovar typhimurium.salmonellae are often present as immobilized cells in food products in the form of micro-colonies. despite this, most research into salmonella physiology has been performed with bacteria grown as planktonic cultures. in the current study, we compared the transcriptome of planktonic and immobilized salmonella enterica subsp. enterica serovar typhimurium (s. typhimurium) subjected to 30 min of heat stress at 45 °c. the expression of 538 genes was differently regulated between the two conditions af ...201323200655
analysis of bacterial diversity during the fermentation of inyu, a high-temperature fermented soy sauce, using nested pcr-denaturing gradient gel electrophoresis and the plate count method.the diversity of bacteria associated with the fermentation of inyu, also known as black soy sauce, was studied through the nested pcr-denaturing gradient gel electrophoresis (dgge) of samples collected from the fermentation stages of the inyu production process. the dgge profiles targeted the bacterial 16s rdna and revealed the presence of citrobacter farmeri, enterobacter cloacae, enterobacter hormaechei, enterococcus faecium, klebsiella pneumoniae, pantoea agglomerans, salmonella enterica, ser ...201323200659
a dry-inoculation method for nut kernels.a dry-inoculation method for almonds and walnuts was developed to eliminate the need for the postinoculation drying required for wet-inoculation methods. the survival of salmonella enterica enteritidis pt 30 on wet- and dry-inoculated almond and walnut kernels stored under ambient conditions (average: 23 °c; 41 or 47% rh) was then compared over 14 weeks. for wet inoculation, an aqueous salmonella preparation was added directly to almond or walnut kernels, which were then dried under ambient cond ...201323200663
isolation of highly persistent mutants of salmonella enterica serovar typhimurium reveals a new toxin-antitoxin module.bacterial persistence is characterized by the ability of a subpopulation within bacterial cultures to survive exposure to antibiotics and other lethal treatments. the surviving persisters are not the result of genetic changes but represent epigenetic variants that are in a physiological state where growth is inhibited. since characterization of persisters has been performed mainly in escherichia coli k-12, we sought to identify mechanisms of persistence in the pathogen salmonella enterica serova ...201323204462
characterization of aminoglycoside-modifying enzymes in enterobacteriaceae clinical strains and characterization of the plasmids implicated in their diffusion.a total of 788 clinical enterobacteriaceae were collected to describe the aminoglycoside-modifying genes (ame genes) and to characterize the plasmids that carry these genes. among the 788 strains collected, 330 (41.8%) were aminoglycoside-resistant: 264 escherichia coli (80%), 33 proteus mirabilis (10%), 10 klebsiella pneumoniae (3%), six k. oxytoca (1.8%), five enterobacter cloacae (1.5%), three morganella morganii (0.9%), three providencia stuartii (0.9%), two salmonella enterica (0.6%), and o ...201323206280
prevalence and characterization of foodborne pathogens in dairy cattle in the eastern part of japan.to investigate the prevalence and characterization of foodborne pathogens [campylobacter spp., shiga toxin-producing escherichia coli (stec), listeria monocytogenes and salmonella spp.] in dairy cows, rectal content grab samples were collected from 250 dairy cows reared on 25 dairy farms in eastern japan from december 2010 through february 2011. campylobacter jejuni was isolated from 106 (42%) cows on 23 (92%) farms, stec o157 from three cows on one farm, l. monocytogenes from three cows on anot ...201323208291
epithelial cells augment barrier function via activation of the toll-like receptor 2/phosphatidylinositol 3-kinase pathway upon recognition of salmonella enterica serovar typhimurium curli fibrils in the gut.curli fibrils, the best-characterized functional bacterial amyloids, are an important component of enterobacterial biofilms. we have previously shown that curli fibrils are recognized by the toll-like receptor 2 (tlr2)/tlr1 heterodimer complex. utilizing polarized t-84 cells, an intestinal epithelial cell line derived from colon carcinoma grown on semipermeable tissue culture inserts, we determined that infection with a salmonella enterica serovar typhimurium csgba mutant, which does not express ...201323208603
utilization and accessibility of healthcare on pemba island, tanzania: implications for health outcomes and disease surveillance for typhoid fever.salmonella enterica serotype typhi (s. typhi) was estimated to cause over 200,000 deaths and more than 21 million illnesses worldwide, including over 400,000 illnesses in africa. the current study was conducted in four villages on pemba island, zanzibar, in 2010. we present data on policy makers', health administrators', and village residents' and leaders' perceptions of typhoid fever, and hypothetical and actual health care use among village residents for typhoid fever. qualitative data provide ...201323208887
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