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evanescent wave fiber optic biosensor for salmonella detection in food.salmonella enterica is a major food-borne pathogen of world-wide concern. sensitive and rapid detection methods to assess product safety before retail distribution are highly desirable. since salmonella is most commonly associated with poultry products, an evanescent wave fiber-optic assay was developed to detect salmonella in shell egg and chicken breast and data were compared with a time-resolved fluorescence (trf) assay. anti-salmonella polyclonal antibody was immobilized onto the surface of ...200922346728
distribution and genetic diversity of salmonella enterica in the upper suwannee river.the suwannee river spans the florida/georgia border to the gulf of mexico, and contributes to regional irrigation and recreational activities. association of salmonella enterica with these resources may result in the contamination of produce and disease outbreaks. therefore, surface water was examined for the distribution of s. enterica at multiple time points from 4 sites on the upper suwannee river. isolates were confirmed by detection of the inva gene, and 96% of all samples were positive for ...201122347228
pcr-restriction fragment length polymorphism analysis of fljb gene in salmonella enterica subspecies enterica serovar typhimurium isolated from avians.economic constraint of diseases arising from salmonella typhimurium causes the study of this zoonotic organism more important. most studies on identification and characterization of s. typhimurium are conducted at dna level. flagellin genes (flic and fljb genes encoding phase-1 and phase-2 flagella, respectively) are useful as a model system for studying genetic differentiation. the objectives of the present study were to identify the polymorphism of fljb among avians in different regions by the ...201022347569
antimicrobial resistance profile and presence of class i integrongs among salmonella enterica serovars isolated from human clinical specimens in tehran, iran.salmonella is one of the leading causes of food-borne diseases. increasing occurrence of antimicrobial resistance, especially multidrug-resistance, in salmonella serovars is a major public health problem worldwide. this study was carried out to detect class i integrons and antibiotic resistance profiles in clinical isolates of salmonella serovars collected from seven hospitals in tehran during november 2009 to june 2010.201122347592
screening for efflux pump systems of bacteria by the new acridine orange agar method.development of a non-toxic, fluorescent-based, agar system for the screening of overexpressed bacterial efflux pump systems with common, inexpensive uv accessories.201322351659
igg keeps virulent salmonella from evading dendritic cell uptake.dendritic cells (dcs) are phagocytic professional antigen-presenting cells that can prime naive t cells and initiate anti-bacterial immunity. however, several pathogenic bacteria have developed virulence mechanisms to impair dc function. for instance, salmonella enterica serovar typhimurium can prevent dcs from activating antigen-specific t cells. in addition, it has been described that the salmonella pathogenicity island 1 (spi-1), which promotes phagocytosis of bacteria in non-phagocytic cells ...201222352313
reverse-transcriptase loop-mediated isothermal amplification as a rapid screening/monitoring tool for salmonella enterica detection in liquid whole eggs.reverse-transcriptase loop-mediated isothermal amplification (rt-lamp) is a novel molecular detection method that is specific, fast, and simple. it is based on reverse transcription followed by dna amplification using the bst dna polymerase large fragment requiring one temperature and a simple waterbath, without the need for any expensive equipment. detection is by turbidity or agarose gel electrophoresis. our objective was to apply this lamp-based technology to rapidly and sensitively detect sa ...201222352954
wild birds as sentinels for multiple zoonotic pathogens along an urban to rural gradient in greater chicago, illinois.wild birds are important in the maintenance and transmission of many zoonotic pathogens. with increasing urbanization and the resulting emergence of zoonotic diseases, it is critical to understand the relationships among birds, vectors, zoonotic pathogens, and the urban landscape. here, we use wild birds as sentinels across a gradient of urbanization to understand the relative risk of diseases caused by three types of zoonotic pathogens: salmonella pathogens, mosquito-borne west nile virus (wnv) ...201222353581
peroral ciprofloxacin therapy impairs the generation of a protective immune response in a mouse model for salmonella enterica serovar typhimurium diarrhea, while parenteral ceftriaxone therapy does not.nontyphoidal salmonella (nts) species cause self-limiting diarrhea and sometimes severe disease. antibiotic treatment is considered only in severe cases and immune-compromised patients. the beneficial effects of antibiotic therapy and the consequences for adaptive immune responses are not well understood. we used a mouse model for salmonella diarrhea to assess the effects of per os treatment with ciprofloxacin (15 mg/kg of body weight intragastrically 2 times/day, 5 days) or parenteral ceftriaxo ...201222354292
complete genome sequence of salmonella enterica serovar typhimurium bacteriophage spn3ub.salmonella is one of the major pathogenic bacteria that cause food poisoning. to elucidate the host infection mechanism of salmonella enterica serovar typhimurium-targeting phages, the bacteriophage spn3ub was isolated from a chicken fecal sample. this phage belongs morphologically to the siphoviridae family and infects the host via the o antigen of lipopolysaccharide (lps). to further understand its infection mechanism, we completely sequenced and analyzed the genome. here, we announce its comp ...201222354944
gene expression analysis of salmonella enterica enteritidis nal(r) and salmonella enterica kentucky 3795 exposed to hcl and acetic acid in rich medium.in the united states, serovar kentucky has become one of the most frequently isolated salmonella enterica serovars from chickens. the reasons for this prevalence are not well understood. phenotypic comparisons of poultry salmonella isolates belonging to various serovars demonstrated that serovar kentucky isolates differed from those of most other serovars in their response to acid. microarray and qpcr analyses were performed with aerated exponentially growing poultry isolates, salmonella enteric ...201222356573
laboratory-based surveillance of non-typhoidal salmonella infections in guangdong province, china.salmonella is one of the most common foodborne pathogens in humans. laboratory-based surveillance for non-typhoidal salmonella infection was conducted in guangdong province, china to improve understanding about the disease burden and detection of dispersed outbreaks. salmonella isolated from patients with diarrhea were sent from 16 sentinel hospitals to local public health laboratories for confirmation, serotyping, antimicrobial susceptibility testing, and pulsed-field gel electrophoresis (pfge) ...201222356574
a third mode of surface-associated growth: immobilization of salmonella enterica serovar typhimurium modulates the rpos-directed transcriptional programme.although the growth of bacteria has been studied for more than a century, it is only in recent decades that surface-associated growth has received attention. in addition to the well-characterized biofilm and swarming lifestyles, bacteria can also develop as micro-colonies supported by structured environments in both food products and the gi tract. this immobilized mode of growth has not been widely studied. to develop our understanding of the effects of immobilization upon a food-borne bacterial ...201222356617
multidrug-resistant typhoid fever with neurologic findings on the malawi-mozambique border.salmonella enterica serovar typhi causes an estimated 22 million cases of typhoid fever and 216 000 deaths annually worldwide. we investigated an outbreak of unexplained febrile illnesses with neurologic findings, determined to be typhoid fever, along the malawi-mozambique border.201222357702
a large outbreak of typhoid fever associated with a high rate of intestinal perforation in kasese district, uganda, 2008-2009.salmonella enterica serovar typhi (salmonella typhi) causes an estimated 22 million typhoid fever cases and 216 000 deaths annually worldwide. in africa, the lack of laboratory diagnostic capacity limits the ability to recognize endemic typhoid fever and to detect outbreaks. we report a large laboratory-confirmed outbreak of typhoid fever in uganda with a high proportion of intestinal perforations (ips).201222357703
[serotypes and antimicrobial susceptibility patterns of salmonella strains isolated from food in cuba].the serotypes of 178 isolates of salmonella enterica taken from food in different regions of cuba between january 2008 and december 2009 were identified, and the antimicrobial susceptibility pattern of 100 selected isolates was determined by strata sampling. a total of 20 salmonella serotypes were identified, with a predominance of s. enteritidis (23%), s. agona (13.5%), and s. london (11.2%). of all the strains, 75% were resistant or presented intermediate resistance to at least one of the drug ...201122358403
isolation and preliminary characterization of amino acid substitution mutations that increase the activity of the osmoregulated prop protein of salmonella enterica serovar typhimurium.in enterobacteriaceae, the prop protein, which takes up proline and glycine betaine, is subject to a post-translational control mechanism that increases its activity at high osmolarity. in order to investigate the osmoregulatory mechanism of the salmonella enterica prop, we devised a positive selection for mutations that conferred increased activity on this protein at low osmolarity. the selection involved the isolation of mutations in a proline auxotroph that resulted in increased accumulation ...201222360681
salmonella enterica serovar paratyphi a: an emerging cause of febrile illness in nepal.with an aim to evaluate the isolation rate and antibiotic susceptibility pattern in salmonella enterica serovar typhi and s. paratyphi a, 656 blood samples collected from clinically diagnosed enteric fever patients at national public health laboratory, nepal during january through december 2008 were processed. isolates were identified by standard microbiological procedures including serotyping. antibiotic susceptibility testing was performed by disc diffusion method and minimum inhibitory concen ...201122364084
decreased colonization of chicks by salmonella enterica serovar gallinarum expressing mannose-sensitive fimh adhesin from salmonella enterica serovar enteritidis.to investigate the role of non-hemagglutinating type 1 fimbriae in the pathogenesis of salmonella gallinarum, the isogenic mutant elaborating type 1 fimbriae with mannose-sensitive (ms) variant of the fimh adhesin from salmonella enteritidis and the mutant strain with no fimh expression were constructed. their binding to chicken leukocytes in vitro and invasiveness in 1-day-old chicks were studied. our results demonstrated that s. gallinarum type 1 fimbriae with an endogenous variant of the fimh ...201222364838
repression of salmonella enterica phop expression by small molecules from physiological bile.infection with salmonella enterica serovar typhi in humans causes the life-threatening disease typhoid fever. in the laboratory, typhoid fever can be modeled through the inoculation of susceptible mice with salmonella enterica serovar typhimurium. using this murine model, we previously characterized the interactions between salmonella typhimurium and host cells in the gallbladder and showed that this pathogen can successfully invade gallbladder epithelial cells and proliferate. additionally, we ...201222366421
isolation of a paenibacillus sp. strain and structural elucidation of its broad-spectrum lipopeptide antibiotic.this research was initiated to search for novel antimicrobial compounds produced by food or environmental microorganisms. a new bacterial strain, designated osy-se, which produces a unique and potent antimicrobial agent was isolated from soil. the isolate was identified as a paenibacillus sp. through cultural, biochemical, and genetic analyses. an antimicrobial compound was extracted from paenibacillus osy-se with acetonitrile and purified using liquid chromatography. after analyses by mass spec ...201222367082
efficacy of biocides used in the modern food industry to control salmonella enterica, and links between biocide tolerance and resistance to clinically relevant antimicrobial compounds.biocides play an essential role in limiting the spread of infectious disease. the food industry is dependent on these agents, and their increasing use is a matter for concern. specifically, the emergence of bacteria demonstrating increased tolerance to biocides, coupled with the potential for the development of a phenotype of cross-resistance to clinically important antimicrobial compounds, needs to be assessed. in this study, we investigated the tolerance of a collection of susceptible and mult ...201222367085
genome scanning for conditionally essential genes in salmonella enterica serotype typhimurium.as more whole-genome sequences become available, there is an increasing demand for high-throughput methods that link genes to phenotypes, facilitating discovery of new gene functions. in this study, we describe a new version of the tn-seq method involving a modified ez:tn5 transposon for genome-wide and quantitative mapping of all insertions in a complex mutant library utilizing massively parallel illumina sequencing. this tn-seq method was applied to a genome-saturating salmonella enterica sero ...201222367088
recent findings about the yersinia enterocolitica phage shock protein response.the phage shock protein (psp) system is a conserved extracytoplasmic stress response in bacteria that is essential for virulence of the human pathogen yersinia enterocolitica. this article summarizes some recent findings about y. enterocolitica psp system function. increased psp gene expression requires the transcription factor pspf, but under non-inducing conditions pspf is inhibited by an interaction with another protein, pspa, in the cytoplasm. a psp-inducing stimulus causes pspa to relocate ...201222367931
copper redistribution in murine macrophages in response to salmonella infection.the movement of key transition metal ions is recognized to be of critical importance in the interaction between macrophages and intracellular pathogens. the present study investigated the role of copper in mouse macrophage responses to salmonella enterica sv. typhimurium. the copper chelator bcs (bathocuproinedisulfonic acid, disodium salt) increased intracellular survival of s. typhimurium within primary mouse bmm (bone-marrow-derived macrophages) at 24 h post-infection, implying that copper co ...201222369063
glycoconjugate vaccine strategies for protection against invasive salmonella infections.salmonella enterica serovars typhi and paratyphi a and b and certain non-typhoidal salmonella enterica (nts) serovars are important causes of invasive salmonella disease worldwide. nts serovars typhimurium and enteritidis typically cause gastroenteritis in healthy children and adults in industrialized countries but in certain hosts (e.g., young infants, the elderly, immunocompromised individuals) they also cause invasive infections. these two serovars also cause invasive disease in infants and y ...201222370510
genomic comparison of the closely related salmonella enterica serovars enteritidis and dublin.the enteritidis and dublin serovars of salmonella enterica are closely related, yet they differ significantly in pathogenicity and epidemiology. s. enteritidis is a broad host range serovar that commonly causes gastroenteritis and infrequently causes invasive disease in humans. s. dublin mainly colonizes cattle but upon infecting humans often results in invasive disease.to gain a broader view of the extent of these differences we conducted microarray-based comparative genomics between several fi ...201222371816
highly resistant salmonella enterica serovar typhi with a novel gyra mutation raises questions about the long-term efficacy of older fluoroquinolones for treating typhoid fever.as a consequence of multidrug resistance, clinicians are highly dependent on fluoroquinolones for treating the serious systemic infection typhoid fever. while reduced susceptibility to fluoroquinolones, which lessens clinical efficacy, is becoming ubiquitous, comprehensive resistance is exceptional. here we report ofloxacin treatment failure in typhoidal patient infected with a novel, highly fluoroquinolone-resistant isolate of salmonella enterica serovar typhi. the isolation of this organism ha ...201222371897
a glycine betaine importer limits salmonella stress resistance and tissue colonization by reducing trehalose production.mechanisms by which salmonella establish chronic infections are not well understood. microbes respond to stress by importing or producing compatible solutes, small molecules that stabilize proteins and lipids. the salmonella locus opuabcd (also called opuc) encodes a predicted importer of the compatible solute glycine betaine. under stress conditions, if glycine betaine cannot be imported, salmonella enterica produce the disaccharide trehalose, a highly effective compatible solute. we demonstrat ...201222375627
transient gut retention and persistence of salmonella through metamorphosis in the lesser mealworm, alphitobius diaperinus (coleoptera: tenebrionidae).this study was undertaken to determine the retention of salmonella through alphitobius diaperinus metamorphosis and its contribution, through defecation, to external contamination.201222380581
ydiv: a dual function protein that targets flhdc for clpxp-dependent degradation by promoting release of dna-bound flhdc complex.ydiv is an eal-like protein that acts as a post-transcriptional, negative regulator of the flagellar master transcriptional activator complex, flhd(4)c(2), in salmonella enterica to couple flagellar gene expression to nutrient availability. mutants defective in clpxp protease no longer exhibit ydiv-dependent inhibition of flhd(4)c(2)-dependent transcription under moderate ydiv expression conditions. clpxp protease degrades flhd(4)c(2), and this degradation is accelerated in the presence of ydiv. ...201222380597
salmonella enterica shedding in hospitalized horses and associations with diarrhea occurrence among their stablemates and gastrointestinal-related illness or death following discharge.to evaluate the potential association between salmonella enterica shedding in hospitalized horses and the risk of diarrhea among stablemates, and to characterize gastrointestinal-related illness and death following discharge among horses that shed s. enterica while hospitalized.201222380811
cytokine signaling in splenic leukocytes from vaccinated and non-vaccinated chickens after intravenous infection with salmonella enteritidis.in order to design a new salmonella enterica vaccine, one needs to understand how naive and immune chickens interact differently when exposed to s. enterica. in this study we therefore determined the immune response of vaccinated and non-vaccinated chickens after intravenous infection with salmonella enterica serovar enteritidis (s. enteritidis). using flow cytometry we showed that 4 days post infection (dpi), counts of cd4 and b-lymphocytes did not change, cd8 and γδ t-lymphocytes decreased and ...201222384225
stability, entrapment and variant formation of salmonella genomic island 1.the salmonella genomic island 1 (sgi1) is a 42.4 kb integrative mobilizable element containing several antibiotic resistance determinants embedded in a complex integron segment in104. the numerous sgi1 variants identified so far, differ mainly in this segment and the explanations of their emergence were mostly based on comparative structure analyses. here we provide experimental studies on the stability, entrapment and variant formation of this peculiar gene cluster originally found in s. typhim ...201222384263
differential outcome of infection with attenuated salmonella in myd88-deficient mice is dependent on the route of administration.activation of the innate immune system is a prerequisite for the induction of adaptive immunity to both infectious and non-infectious agents. tlrs are key components of the innate immune recognition system and detect pathogen-associated molecular patterns. most tlrs utilize the myd88 adaptor for their signaling pathways. in the current study, we investigated innate and adaptive immune responses to primary as well as secondary salmonella infections in myd88-deficient (myd88(-/-)) mice. using i.p. ...201322386951
discovery and characterization of coturnix chinensis avian β-defensin 10, with broad antibacterial activity.a novel avian β-defensin (avbd), avbd10, was discovered in the liver and bone marrow tissues from chinese painted quail (coturnix chinensis) in the present study. the complete nucleotide sequence of quail avbd10 contains a 207-bp open reading frame that encodes 68 amino acids. the quail avbd10 was expressed widely in all the tissues from quails except the tongue, crop, breast muscle, and thymus and was highly expressed in the bone marrow. in contrast to the expression pattern of avbd10 in tissue ...201222389044
strand length-dependent antimicrobial activity and membrane-active mechanism of arginine- and valine-rich β-hairpin-like antimicrobial peptides.antimicrobial peptides with amphipathic β-hairpin-like structures have potent antimicrobial properties and low cytotoxicity. the effect of vr or rv motifs on β-hairpin-like antimicrobial peptides has not been investigated. in this study, a series of β-hairpin-like peptides, ac-c(vr)(n)(d)pg (rv)(n)c-nh(2) (n = 1, 2, 3, 4, or 5), were synthesized, and the effect of chain length on antimicrobial activity was evaluated. the antimicrobial activity of the peptides initially increased and then decreas ...201222391533
cell viability and immunostimulating and protective capacities of bifidobacterium longum 51a are differentially affected by technological variables in fermented milks.to investigate the cell viability of bifidobacterium longum 5(1a) in fermented milks and to study its immunostimulating and protective capacity against salmonella enterica ssp. enterica serovar typhimurium infection in mice.201222394272
antimicrobial and safety properties of lactobacilli isolated from two cameroonian traditional fermented foods.twenty-one lactobacillus isolates from "sha'a" (a maize - based fermented beverage) and "kossam" (traditionally fermented cow milk) were selected in accordance with their antagonistic activities and tested for their bacteriocinogenic potential as well as safety properties. these isolates were preliminarily identified as lactobacillus plantarum (62%), lactobacillus rhamnosus (24%), lactobacillus fermentum (10%) and lactobacillus coprophilus (4%) based on phenotypic characteristics and rep-pcr gen ...201122396914
synthesis of a tetrasaccharide analog corresponding to the repeating unit of the o-polysaccharide of salmonella enterica o59: unexpected stereo outcome in glycosylation.convergent synthesis of a tetrasaccharide analog corresponding to the repeating unit of the o-polysaccharide of salmonella enterica o59 is presented. a thioglycoside disaccharide donor was prepared by the glycosylation of two thioglycosides by tuning their relative reactivity. an unexpected stereochemical outcome was observed in a glycosylation using an ethyl 2-o-acetyl-3-o-benzyl-4,6-o-bensylidene-thio-galactoside donor, where the alpha-galactoside was formed in spite of the presence of the 2-o ...201222398254
effect of xylanase and a blend of essential oils on performance and salmonella colonization of broiler chickens challenged with salmonella heidelberg.the present experiment examined the influence of xylanase supplementation and a blend of essential oils (eo; cinnamaldehyde and thymol) on performance and salmonella horizontal transmission in broiler chickens challenged with salmonella. two thousand 1-d-old broiler chicks were randomly assigned to 5 dietary treatments (8 pens/treatment of 50 male broilers each). four dietary treatments were challenged with salmonella: 1) control, 2) basal diets supplemented with eo, 3) basal diet supplemented w ...201222399734
development and clinical verification of a loop-mediated isothermal amplification method for detection of salmonella species in suspect infected ducks.to detect salmonella spp. in suspect infected ducks, a loop-mediated isothermal amplification (lamp) assay was developed. with the help of this assay, we can detect salmonella enterica serovar enteriditis and salmonella enterica serovar anatis above 6.0 cfu/test and 4.8 cfu/test, respectively, in pure-culture conditions, even in the existence of 0.01 g of duck liver or spleen homogenates; the detection thresholds were still achieved at 6.0 cfu per test tube. further experiments of the test strai ...201222399738
an evaluation of the effect of sodium bisulfate as a feed additive on salmonella enterica serotype enteritidis in experimentally infected broilers.the colonization of broiler chickens with salmonella can pose serious health and economic risks for both consumers and the poultry industry. because colonization with salmonella can lead to subsequent contamination of chicken carcasses during processing, preemptive control measures should include the reduction of this pathogen in chickens before slaughter. in this study, we evaluated the effect of sodium bisulfate, a potential antimicrobial feed additive, on salmonella colonization of experiment ...201222399744
loxoribine pretreatment reduces salmonella enteritidis organ invasion in 1-day-old chickens.young poultry exhibit a transient colonization by some food-borne pathogens, including salmonella, during the first week of life that stems from immature innate and acquired defense mechanisms. consequently, modulation of the hosts' natural immune response is emerging as an important area of interest for food animal producers, including the poultry industry. toll-like receptor (tlr) agonists have been shown to boost the innate immune response in young chickens and increase their resistance to co ...201222399745
clonal dissemination of salmonella enterica serovar infantis in germany.salmonella enterica serovar infantis (salmonella infantis) is consistently isolated from broiler chickens, pigs, and humans worldwide. this study investigated 93 epidemiologically unrelated salmonella infantis strains isolated in germany between 2005 and 2008 in respect to their transmission along the food chain. various phenotypic and genotypic methods were applied, and the pathogenicity and resistance gene repertoire was determined. phenotypically, 66% of the strains were susceptible to all 17 ...201222401270
microelectrode array biosensor for studying carbohydrate-mediated interactions.carbohydrate-mediated host-pathogen interactions are essential to bacterial and viral pathogenesis, and represent an attractive target for the development of antiadhesives to prevent infection. we present a versatile microelectrode array-based platform to investigate carbohydrate-mediated protein and bacterial binding, with the objective of developing a generalizable method for screening inhibitors of host-microbe interactions. microelectrode arrays are well suited for interrogating biological b ...201222405843
occurrence and antibiotic resistance of multiple salmonella serotypes recovered from water, sediment and soil on mid-atlantic tomato farms.salmonella outbreaks associated with the consumption of raw tomatoes have been prevalent in recent years. however, sources of salmonella contamination of tomatoes remain poorly understood. the objectives of this study were to identify ecological reservoirs of salmonella on tomato farms, and to test antimicrobial susceptibilities of recovered salmonella isolates. fourteen mid-atlantic tomato farms in the u.s. were sampled in 2009 and 2010. groundwater, irrigation pond water, pond sediment, irriga ...201222406288
[epidemiology, microbiology, and outcomes of septicemia in children treated at the charles de gaulle university pediatric hospital in burkina faso].the aim of this study is to describe the epidemiological and microbiological characteristics and outcome of children with septicemia at the charles de gaulle university pediatric hospital of ouagadougou to help improve probabilistic antibiotic therapy in this type of infection. this retrospective descriptive study covered all the children from 0 to 15 years old seen over a period of 7 years in any hospital department with suspected bacteriemia and for whom the bacteriology laboratory performed a ...201122407247
functional characterization of udp-glucose:undecaprenyl-phosphate glucose-1-phosphate transferases of escherichia coli and caulobacter crescentus.escherichia coli k-12 wcaj and the caulobacter crescentus hfse, pssy, and pssz enzymes are predicted to initiate the synthesis of colanic acid (ca) capsule and holdfast polysaccharide, respectively. these proteins belong to a prokaryotic family of membrane enzymes that catalyze the formation of a phosphoanhydride bond joining a hexose-1-phosphate with undecaprenyl phosphate (und-p). in this study, in vivo complementation assays of an e. coli k-12 wcaj mutant demonstrated that wcaj and pssy can c ...201222408159
genomic variation in salmonella enterica core genes for epidemiological typing.technological advances in high throughput genome sequencing are making whole genome sequencing (wgs) available as a routine tool for bacterial typing. standardized procedures for identification of relevant genes and of variation are needed to enable comparison between studies and over time. the core genes--the genes that are conserved in all (or most) members of a genus or species--are potentially good candidates for investigating genomic variation in phylogeny and epidemiology.201222409488
survival and growth of epidemically successful and nonsuccessful salmonella enterica clones after freezing and dehydration.the spread of epidemically successful nontyphoidal salmonella clones has been suggested as the most important cause of salmonellosis in industrialized countries. factors leading to the emergence of success clones are largely unknown, but their ability to survive and grow after physical stress may contribute. during epidemiological studies, a mathematical model was developed that allowed estimation of a factor (q) accounting for the relative ability of salmonella serovars with different antimicro ...201222410218
dispersal of salmonella typhimurium by rain splash onto tomato plants.outbreaks of salmonella enterica have increasingly been associated with tomatoes and traced back to production areas, but the spread of salmonella from a point source onto plants has not been described. splash dispersal by rain could be one means of dissemination. green fluorescent protein-labeled, kanamycin-resistant salmonella enterica sv. typhimurium dispensed on the surface of plastic mulch, organic mulch, or soil at 10⁸ cfu/cm² was used as the point source in the center of a rain simulator. ...201222410220
high pressure inactivation of escherichia coli, campylobacter jejuni, and spoilage microbiota on poultry meat.this study evaluated the high pressure inactivation of campylobacter jejuni, escherichia coli, and poultry meat spoilage organisms. all treatments were performed in aseptically prepared minced poultry meat. treatment of 19 strains of c. jejuni at 300 mpa and 30°c revealed a large variation of pressure resistance. the recovery of pressure-induced sublethally injured c. jejuni depended on the availability of iron. the addition of iron content to enumeration media was required for resuscitation of ...201222410223
survival of campylobacter jejuni and salmonella enterica typhimurium in vacuum-packed, moisture-enhanced pork.the abilities of campylobacter jejuni and salmonella enterica typhimurium to survive in vacuum-packaged, moisture-enhanced pork stored at 4 or 10°c were examined. pork loins were surface inoculated with either c. jejuni or salmonella typhimurium and then moisture enhanced to a target of 10 or 20%. the enhanced pork loins were sliced 1 cm thick and vacuum packaged. a pork loin without moisture enhancement was sliced and vacuum packaged as a control. samples were collected, plated, and the numbers ...201222410234
characterization of salmonella type iii secretion hyper-activity which results in biofilm-like cell aggregation.we have previously reported the cloning of the salmonella enterica serovar typhimurium spi-1 secretion system and the use of this clone to functionally complement a δspi-1 strain for type iii secretion activity. in the current study, we discovered that s. typhimurium cultures containing cloned spi-1 display an adherent biofilm and cell clumps in the media. this phenotype was associated with hyper-expression of spi-1 type iii secretion functions. the biofilm and cell clumps were associated with c ...201222412985
glass wool filters for concentrating waterborne viruses and agricultural zoonotic pathogens.the key first step in evaluating pathogen levels in suspected contaminated water is concentration. concentration methods tend to be specific for a particular pathogen group, for example us environmental protection agency method 1623 for giardia and cryptosporidium, which means multiple methods are required if the sampling program is targeting more than one pathogen group. another drawback of current methods is the equipment can be complicated and expensive, for example the viradel method with th ...201222415031
system-wide studies of n-lysine acetylation in rhodopseudomonas palustris reveal substrate specificity of protein acetyltransferases.n-lysine acetylation is a posttranslational modification that has been well studied in eukaryotes and is likely widespread in prokaryotes as well. the central metabolic enzyme acetyl-coa synthetase is regulated in both bacteria and eukaryotes by acetylation of a conserved lysine residue in the active site. in the purple photosynthetic α-proteobacterium rhodopseudomonas palustris, two protein acetyltransferases (rppat and the newly identified rpkata) and two deacetylases (rpldaa and rpsrtn) regul ...201222416131
survival of salmonella typhi and shigella dysenteriae in dehydrated infant formula.powdered infant formula has previously been linked to the transmission of various bacterial pathogens in infants resulting in life-threatening disease and death. survival studies of 2 common foodborne pathogens, salmonella enterica serovar typhi and shigella dysenteriae, in powdered infant formula have not been previously studied despite the potentially devastating consequences from ingestion of these organisms, particularly by newborns, in case of a natural or deliberate contamination event. th ...201122417504
characterization of dals, an atp-binding cassette transporter for d-alanine, and its role in pathogenesis in salmonella enterica.expansion into new host niches requires bacterial pathogens to adapt to changes in nutrient availability and to evade an arsenal of host defenses. horizontal acquisition of salmonella pathogenicity island (spi)-2 permitted the expansion of salmonella enterica serovar typhimurium into the intracellular environment of host cells by allowing it to deliver bacterial effector proteins across the phagosome membrane. this is facilitated by the ssra-ssrb two-component regulatory system and a type iii se ...201222418438
evasion of human innate immunity without antagonizing tlr4 by mutant salmonella enterica serovar typhimurium having penta-acylated lipid a.modification of a lipid a moiety in gram-negative bacterial lps to a less acylated form is thought to facilitate bacterial evasion of host innate immunity, thereby enhancing pathogenicity. the contribution of less-acylated lipid a to interactions of whole bacterial cells with host cells (especially in humans) remains unclear. mutant strains of salmonella enterica serovar typhimurium with fewer acylated groups were generated. the major lipid a form in wild-type (wt) and the mutant kcs237 strain i ...201222419537
bacteriophage-encoded bacterial virulence factors and phage-pathogenicity island interactions.the role of bacteriophages as natural vectors for some of the most potent bacterial toxins is well recognized and includes classical type i membrane-acting superantigens, type ii pore-forming lysins, and type iii exotoxins, such as diphtheria and botulinum toxins. among gram-negative pathogens, a novel class of bacterial virulence factors called effector proteins (eps) are phage encoded among pathovars of escherichia coli, shigella spp., and salmonella enterica. this chapter gives an overview of ...201222420852
allele-specific primer polymerase chain reaction for a single nucleotide polymorphism (c1205t) of swine toll-like receptor 5 and comparison of the allelic frequency among several pig breeds in japan and the czech republic.in the present study, an allele-specific primer-polymerase chain reaction (asp-pcr) for genotyping a single nucleotide polymorphism (snp) of swine toll-like receptor 5 (tlr5) (c1205t; p402l) that is related to the impaired recognition of salmonella enterica serovar choleraesuis (sc) was developed. the allele frequencies in several pig breeds in japan and the czech republic were also compared. the swine tlr5 c1205t mutation was successfully determined by asp-pcr using genomic dna samples in japan ...201222420886
functions of the salmonella pathogenicity island 2 (spi-2) type iii secretion system effectors.salmonella enterica serovars cause severe disease in humans, such as gastroenteritis and typhoid fever. the bacteria are able to invade and replicate within host cells, including epithelial cells and macrophages. pathogenesis of salmonella is facilitated by a type iii secretion system (t3ss) encoded by genes of salmonella pathogenicity island 2 (spi-2). intracellular replication occurs in a specialized membrane compartment, the salmonella-containing vacuole (scv), and depends on translocation of ...201222422755
use of rapidchek® select™ salmonella to detect shedding of live attenuated salmonella enterica serovar typhi vaccine strains.identification of individuals shedding salmonella enterica serovar typhi in stool is imperative during clinical trial safety evaluations. recovery of live attenuated s. typhi vaccine strains can be difficult because the mutations necessary for safety in humans often compromise survival in stringent selective enrichment media. rapidchek® select™ salmonella is a highly sensitive detection method for s. enterica species which utilizes a bacteriophage cocktail designed to reduce the growth of compet ...201222425882
preparation and evaluation of immunogenic conjugates of salmonella enterica serovar typhi o-specific polysaccharides with diphtheria toxoid.typhoid fever, caused by salmonella enterica serovar typhi (s. typhi), is a major health problem particularly in developing countries. the available vaccines have certain limitations regarding their efficacy, and inability to induce an immune response especially in individuals under 2 years of age. conjugate vaccines which consist of a bacteria-specific polysaccharide chemically bound to a carrier protein overcome these problems by inducing a t-cell dependent immune response characterized by enh ...201222426380
the late endosomal adaptor p14 is a macrophage host-defense factor against salmonella infection.the outcome of an infection depends on the balance between host resistance and bacterial virulence. here, we show that the late endosomal adaptor p14 (also known as lamtor2) is one of the components for cellular host defense against the intracellular pathogen salmonella enterica serovar typhimurium. during salmonella infection, the complex of p14 and mp1 is required for the accurately timed transport of salmonella through the endolysosomal system. loss of p14 opens a time window that allows salm ...201222427693
divergent roles of salmonella pathogenicity island 2 and metabolic traits during interaction of s. enterica serovar typhimurium with host cells.the molecular mechanisms of virulence of the gastrointestinal pathogen salmonella enterica are commonly studied using cell culture models of infection. in this work, we performed a direct comparison of the interaction of s. enterica serovar typhimurium (s. typhimurium) with the non-polarized epithelial cell line hela, the polarized cell lines caco2, t84 and mdck, and macrophage-like raw264.7 cells. the ability of s. typhimurium wild-type and previously characterized auxotrophic mutant strains to ...201222427996
engineered protein nano-compartments for targeted enzyme localization.compartmentalized co-localization of enzymes and their substrates represents an attractive approach for multi-enzymatic synthesis in engineered cells and biocatalysis. sequestration of enzymes and substrates would greatly increase reaction efficiency while also protecting engineered host cells from potentially toxic reaction intermediates. several bacteria form protein-based polyhedral microcompartments which sequester functionally related enzymes and regulate their access to substrates and othe ...201222428024
riboswitch control of rho-dependent transcription termination.riboswitches are rna sensors that regulate gene expression upon binding specific metabolites or ions. bacterial riboswitches control gene expression primarily by promoting intrinsic transcription termination or by inhibiting translation initiation. we now report a third general mechanism of riboswitch action: governing the ability of the rna-dependent helicase rho to terminate transcription. we establish that rho promotes transcription termination in the mg(2+)-sensing mgta riboswitch from salmo ...201222431636
twenty-six years of enteric fever in australia: an epidemiological analysis of antibiotic resistance.to determine incidence and trends in antibiotic resistance in australian salmonella enterica subspecies enterica serovars typhi (s. typhi) and paratyphi (s. paratyphi) isolates over the past 26 years.201222432672
a simple method for construction of pir+ enterobacterial hosts for maintenance of r6k replicon plasmids.the r6k replicon is one of the best studied bacterial plasmid replicons. replication of the r6k plasmid and derivatives harboring its γ origin of replication (ori(r6kγ)) is dependent on the pir gene-encoded π protein. originally encoded by r6k, this protein is usually provided in trans in hosts engineered to support replication of plasmids harboring ori(r6kγ). in escherichia coli this is commonly achieved by chromosomal integration of pir either via lysogenization with a λpir phage or homologous ...201222433797
the promoter architectural landscape of the salmonella phop regulon.the dna-binding protein phop controls virulence and mg²⁺ homeostasis in the gram-negative pathogen salmonella enterica serovar typhimurium. phop regulates expression of a large number of genes that differ both in their ancestry and in the biochemical functions and physiological roles of the encoded products. this suggests that phop-regulated genes are differentially expressed. to understand how a bacterial activator might generate varied gene expression behaviour, we investigated the cis-acting ...201222435712
loss of flhe in the flagellar type iii secretion system allows proton influx into salmonella and escherichia coli.flhe belongs to the flhbae flagellar operon in enterobacteria, whose first two members function in type iii secretion (t3s). in salmonella enterica, absence of flhe affects swarming, but not swimming, motility. based on a chance observation of a 'green' colony phenotype of flhe mutants on ph indicator plates containing glucose, we have established that this phenotype is associated with lysis of flagellated cells in an acidic environment created by glucose metabolism. the flhe mutant phenotype of ...201222435757
evolution of the metabolic and regulatory networks associated with oxygen availability in two phytopathogenic enterobacteria.dickeya dadantii and pectobacterium atrosepticum are phytopathogenic enterobacteria capable of facultative anaerobic growth in a wide range of o2 concentrations found in plant and natural environments. the transcriptional response to o2 remains under-explored for these and other phytopathogenic enterobacteria although it has been well characterized for animal-associated genera including escherichia coli and salmonella enterica. knowledge of the extent of conservation of the transcriptional respo ...201222439737
oral and intranasal administration of somatostatin dna vaccine mediated by attenuated salmonella enterica serovar typhimurium to promote growth of piglets.an attenuated strain of salmonella typhimurium has been used as a carrier for oral and intranasal genetic immunization. here, we evaluate the efficacy of a vaccine strain of s. typhimurium. cso22 (pgm-csf/ss, plasmid granulocyte-macrophage colony-stimulating factor/somatostatin) expressing two copies of ss genes. a total of 115 piglets, aged 2 months old, were either orally or intranasally immunized against the vaccine strain cso22 (pgm-csf/ss) with three dosages (5 × 10(10) colony forming units ...201122440175
salmonella enterica serovar typhi strain producing extended-spectrum β-lactamases in dhaka, bangladesh. 201222442289
automated pangenomic analysis in target selection for pcr detection and identification of bacteria by use of ssgenefinder webserver and its application to salmonella enterica serovar typhi.with the advent of high-throughput dna sequencing, more than 4,000 bacterial genomes have been sequenced and are publicly available. we report a user-friendly web platform, ssgenefinder webserver (http://147.8.74.24/ssgenefinder/), which is updated weekly for the automated pangenomic selection of specific targets for direct pcr detection and the identification of clinically important bacteria without the need of gene sequencing. to apply the ssgenefinder webserver for identifying specific target ...201222442318
modification of salmonella typhimurium motility by the probiotic yeast strain saccharomyces boulardii.motility is an important component of salmonella enterica serovar typhimurium (st) pathogenesis allowing the bacteria to move into appropriate niches, across the mucus layer and invade the intestinal epithelium. in vitro, flagellum-associated motility is closely related to the invasive properties of st. the probiotic yeast saccharomyces boulardii biocodex (s.b-b) is widely prescribed for the prophylaxis and treatment of diarrheal diseases caused by bacteria or antibiotics. in case of salmonella ...201222442723
[antagonistic activity of lactobacilli of the colon].study of antagonistic activity of lactobacilli of the colon against members of its autochthonous bacterial flora and agents of some acute infectious and chronic diseases of the gastrointestinal tract.201222442970
optimization of pulsed-field gel electrophoresis protocols for salmonella paratyphi a subtyping.salmonella enterica serovar paratyphi a infection has caused public health problems in some countries in recent years. pulsed-field gel electrophoresis (pfge) has been used for the subtyping and epidemiological investigations of some serotypes of salmonella, mainly in outbreaks caused by non-typhoidal salmonella. in this study, different restriction endonucleases and electrophoresis parameters were compared for the pfge subtyping by using salmonella paratyphi a strain panels. two protocols for t ...201222443482
stress and microbial endocrinology: prospects for ruminant nutrition.the feed efficiency of ruminant meat and dairy livestock can be significantly influenced by factors within their living environments. in particular, events perceived by the animals as stressful (such as parturition, transport or handling) have been found to affect susceptibility to infection. it has been well documented that even minor stress such as weighing can result in an increase in colonisation and faecal shedding of enteric pathogens such as salmonella enterica and escherichia coli o157:h ...201022444620
enhancement of the anti-salmonella immune response in cd154-deficient mice by an attenuated, ifn-γ-expressing, strain of salmonella enterica serovar typhimurium.previously, we demonstrated that cell-cell communications via the cd40-cd154 pathway play a critical role in the induction of type 1 cytokine responses, including il-12 and ifn-γ, which in turn greatly influence the response to salmonella infections. mice genetically deficient in the expression of cd154 exhibited markedly increased susceptibility to infection by an attenuated, double auxotrophic (aroa-arod-) strain, designated brd509, of salmonella enterica serovar typhimurium. in the present st ...201222445817
[detection of salmonella and mycobacterium species in seagulls captured in talcahuano, chile].salmonella can be isolated from the feces of seagulls. therefore these birds can be a vector for dissemination of this pathogen.201122446658
typhoid fever & vaccine development: a partially answered question.typhoid fever is a systemic disease caused by the human specific gram-negative pathogen salmonella enterica serovar typhi (s. typhi). the extra-intestinal infections caused by salmonella are very fatal. the incidence of typhoid fever remains very high in impoverished areas and the emergence of multidrug resistance has made the situation worse. to combat and to reduce the morbidity and mortality caused by typhoid fever, many preventive measures and strategies have been employed, the most importan ...201222446857
presence and persistence of salmonella enterica serotype typhimurium in the phyllosphere and rhizosphere of spray-irrigated parsley.salmonella enterica is one of the major food-borne pathogens associated with ready-to-eat fresh foods. although polluted water might be a significant source of contamination in the field, factors that influence the transfer of salmonella from water to the crops are not well understood, especially under conditions of low pathogen levels in water. the aim of this study was to investigate the short- and long-term (1 h to 28 days) persistence of salmonella enterica serotype typhimurium in the phyllo ...201222447598
high-density transcriptional initiation signals underline genomic islands in bacteria.genomic islands (gis), frequently associated with the pathogenicity of bacteria and having a substantial influence on bacterial evolution, are groups of "alien" elements which probably undergo special temporal-spatial regulation in the host genome. are there particular hallmark transcriptional signals for these "exotic" regions? we here explore the potential transcriptional signals that underline the gis beyond the conventional views on basic sequence composition, such as codon usage and gc prop ...201222448273
biofilm building capacity of salmonella enterica strains from the poultry farm environment.the biofilm (bf) building capacity of different serotypes of salmonella enterica derived from the poultry farm environment was investigated. starting point for the investigation was the question if farm-isolated salmonella serotypes with high importance for poultry meat and egg production are capable of forming a bf under defined laboratory conditions. several isolates from different stages of the production cycle were chosen and compared to laboratory grown strains of the same serotype. bf buil ...201222448648
characterization of multidrug-resistant salmonella enterica serovar heidelberg from a ground turkey-associated outbreak in the united states in 2011. 201222450975
a comparison of methods used to extract bacterial dna from raw milk and raw milk cheese.in this study, we compare seven different methods which have been designed or modified to extract total dna from raw milk and raw milk cheese with a view to its subsequent use for the pcr of bacterial dna.201222452460
infection of zebrafish embryos with intracellular bacterial pathogens.zebrafish (danio rerio) embryos are increasingly used as a model for studying the function of the vertebrate innate immune system in host-pathogen interactions. the major cell types of the innate immune system, macrophages and neutrophils, develop during the first days of embryogenesis prior to the maturation of lymphocytes that are required for adaptive immune responses. the ease of obtaining large numbers of embryos, their accessibility due to external development, the optical transparency of ...201222453760
evolution of inflammasome functions in vertebrates: inflammasome and caspase-1 trigger fish macrophage cell death but are dispensable for the processing of il-1β.members of the nucleotide binding and oligomerization domain-like receptors (nlrs) and the pyd and card domain containing adaptor protein (pycard) assemble into multi-protein platforms, termed inflammasomes, to mediate in the activation of caspase-1 and the subsequent secretion of il-1β and il-18, and the induction of pyroptotic cell death. while the recognition site for caspase-1 is well conserved in mammals, most of the non-mammalian il-1β genes cloned so far lack this conserved site. we repor ...201222456941
a fundamental regulatory mechanism operating through ompr and dna topology controls expression of salmonella pathogenicity islands spi-1 and spi-2.dna topology has fundamental control over the ability of transcription factors to access their target dna sites at gene promoters. however, the influence of dna topology on protein-dna and protein-protein interactions is poorly understood. for example, relaxation of dna supercoiling strongly induces the well-studied pathogenicity gene ssra (also called spir) in salmonella enterica, but neither the mechanism nor the proteins involved are known. we have found that relaxation of dna supercoiling in ...201222457642
acidic ph: enemy or ally for enteric bacteria?the first stress that foodborne pathogens find upon ingestion is the very acidic ph of the stomach of the host. in addition, intracellular pathogens like salmonella are submitted to low ph inside the host cells. two general acid survival systems are found in these organisms: acid resistance mechanisms and acid tolerance responses. these mechanisms involve the synthesis of a series of acid shock proteins. only a subset of these proteins is directly involved in acid survival. this is related to th ...201222460638
extracellular proteins from lactobacillus plantarum bmcm12 prevent adhesion of enteropathogens to mucin.the aim of this study was to study the interference of the extracellular proteins produced by lactobacillus plantarum bmcm12 with the adhesion of some well-known gut pathogens. the extracellular proteins secreted by l. plantarum bmcm12 in mrs broth were precipitated, resolved by sds-page, and identified by tandem mass spectrometry. discordances between the observed and the theoretical molecular masses of several proteins suggested the presence of protein glycosylation, corroborated with specific ...201222461079
functional and expressional analyses of the anti-flhd4c2 factor gene ydiv in escherichia coli.although escherichia coli and salmonella enterica serovar typhimurium have a similar flagellar regulatory system, the response of flagellar synthesis to nutrient conditions is quite different between the two: that is, in low-nutrient conditions, flagellar synthesis is inhibited in salmonella and enhanced in e. coli. in salmonella, this inhibition is mediated by an anti-flhd(4)c(2) factor, ydiv, which is expressed in low-nutrient conditions and binds to flhd(4)c(2) to inhibit the expression of th ...201222461489
complete genome sequence of salmonella enterica subsp. enterica serovar typhi p-stx-12.we report here the complete genome sequence of salmonella enterica subsp. enterica serovar typhi p-stx-12, a clinical isolate obtained from a typhoid carrier in india.201222461552
improving resolution of public health surveillance for human salmonella enterica serovar typhimurium infection: 3 years of prospective multiple-locus variable-number tandem-repeat analysis (mlva).prospective typing of salmonella enterica serovar typhimurium (stm) by multiple-locus variable-number tandem-repeat analysis (mlva) can assist in identifying clusters of stm cases that might otherwise have gone unrecognised, as well as sources of sporadic and outbreak cases. this paper describes the dynamics of human stm infection in a prospective study of stm mlva typing for public health surveillance.201222462487
discovery of an archetypal protein transport system in bacterial outer membranes.bacteria have mechanisms to export proteins for diverse purposes, including colonization of hosts and pathogenesis. a small number of archetypal bacterial secretion machines have been found in several groups of bacteria and mediate a fundamentally distinct secretion process. perhaps erroneously, proteins called 'autotransporters' have long been thought to be one of these protein secretion systems. mounting evidence suggests that autotransporters might be substrates to be secreted, not an autonom ...201222466966
effective inactivation of food pathogens listeria monocytogenes and salmonella enterica by combined treatment of hypericin-based photosensitization and high power pulsed light.the aim of this study was to evaluate the inactivation efficiency of listeria monocytogenes atc(l3) c 7644 and salmonella enterica serovar typhimurium strain ds88 by combined treatment of hypericin (hyp)-based photosensitization and high power pulsed light (hppl).201222469030
increase in extraintestinal infections caused by salmonella enterica subspecies ii-iv.to garner information regarding site of infection and age and sex of persons infected with salmonella enterica subspecies ii-iv, we retrospectively analyzed data on salmonella spp. infections in california, usa, 1985-2009. these subspecies were found to cause significantly more frequent invasive disease (e.g., bacteremia) than did salmonella subspecies i strains.201222469432
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