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inflammation induced by phytomodulatory proteins from the latex of calotropis procera (asclepiadaceae) protects against salmonella infection in a murine model of typhoid fever.laticifer proteins (lp) of calotropis procera were fractionated by ion-exchange chromatography, and the influence of a sub-fraction (lp(pi)) on the inflammatory response of swiss mice challenged by salmonella enterica ser. typhimurium was investigated.201222487850
salmonellosis in cattle: advantages of being an experimental model.salmonellosis is an important disease of cattle caused predominantly by salmonella enterica serotypes typhimurium (s. typhimurium) and dublin (s. dublin). s. typhimurium causes acute enteritis and exudative diarrhea in calves. in addition to enteric disease, s. dublin can cause systemic infections, and may cause abortion in pregnant cows. calves are considered a relevant model for non-typhoidal salmonellosis in humans. experimental oral infections or inoculation of ligated ileal loops in calves ...201222483382
impact of a mutator phenotype on motility and cell adherence in salmonella heidelberg.in this study, we investigated adherence and motility of the hypermutator salmonella enterica heidelberg b182 bovine strain related to a 12bp deletion in muts. this mutator phenotype was associated with increased adherence to epithelial cells and with high expression of fima as shown by real-time rt-pcr. motility studies showed that flic were up-regulated in the b182 strain, while flja and fljb were down-regulated. in order to determine if mutated muts is implicated in this genes expression, iso ...201222483239
efficacy of antimicrobials for the disinfection of pathogen contaminated green bell pepper and of consumer cleaning methods for the decontamination of knives.while there is strong focus on eliminating pathogens from produce at a commercial level, consumers can employ simple methods to achieve additional pathogen reductions in the domestic kitchen. to determine the ability of antimicrobials to decontaminate peppers, samples of green bell pepper were inoculated with salmonella enterica and escherichia coli o157:h7 and then immersed in 3% (v/v) hydrogen peroxide (h₂o₂), 2.5% (v/v) acetic acid (aa), 70% (v/v) ethyl alcohol (etoh), or sterile distilled wa ...201222476008
immune dynamics following infection of avian macrophages and epithelial cells with typhoidal and non-typhoidal salmonella enterica serovars; bacterial invasion and persistence, nitric oxide and oxygen production, differential host gene expression, nf-κb signalling and cell cytotoxicity.poultry-derived food is a common source of infection of human with the non-host-adapted salmonellae while fowl typhoid and pullorum disease are serious diseases in poultry. development of novel immune-based control strategies against salmonella infection necessitates a better understanding of the host-pathogen interactions at the cellular level. intestinal epithelial cells are the first line of defence against enteric infections and the role of macrophages is crucial in salmonella infection and ...201222475571
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
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
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
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
characterization of multidrug-resistant salmonella enterica serovar heidelberg from a ground turkey-associated outbreak in the united states in 2011. 201222450975
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
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
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
salmonella enterica serovar typhi strain producing extended-spectrum β-lactamases in dhaka, bangladesh. 201222442289
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
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
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
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
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
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
[protection against salmonella via immunization with recombinant lactic acid bacteria].mucosal immunization of hens may be effective to prevent contamination of salmonella enterica serovar enteritidis (se) in eggs. lactic acid bacteria have been considered potential vaccine delivery agents because they are safe, immunogenic, and inexpensive. our research group has been investigating the development of oral vaccines against se using a lactobacillus casei strain as an antigen delivery vehicle. recombinant lactobacilli expressing se antigens flic and sipc have been constructed and ad ...201222894061
glycerol supplementation enhances l. reuteri's protective effect against s. typhimurium colonization in a 3-d model of colonic epithelium.the probiotic effects of lactobacillus reuteri have been speculated to partly depend on its capacity to produce the antimicrobial substance reuterin during the reduction of glycerol in the gut. in this study, the potential of this process to protect human intestinal epithelial cells against infection with salmonella enterica serovar typhimurium was investigated. we used a three-dimensional (3-d) organotypic model of human colonic epithelium that was previously validated and applied to study inte ...201222693569
a modified weibull model for growth and survival of listeria innocua and salmonella typhimurium in chicken breasts during refrigerated and frozen storage.the potential of food-borne pathogens to survive and grow during refrigerated and frozen storage has raised serious concerns over the safety of stored poultry products. in this study, the effect of refrigeration and freezing temperatures (-20, -12, 0, 4, and 8°c) on growth and survival of listeria innocua and salmonella enterica serovar typhimurium in raw chicken breasts for storage times of 3, 7, 10, 14, and 21 d were investigated. a modified weibull model was also developed to analyze the micr ...201222582310
[real-time pcr detection and quantification of emerging waterborne pathogens (ewps) and antibiotic resistance genes (args) in the downstream area of jiulong river].the emerging waterborne pathogens (ewps) and antibiotic resistance genes (args) are important for drinking water safety. the detection and quantification of 7 ewps and 4 args were carried out in jiulong river, which is the main water source of southwestern fujian province. the water samples were collected from four sites of the jiulong river downstream area and a drinking water treatment plant nearby. dna was extracted and quantified by real-time (sybr green) pcr methods after the samples were f ...201223213891
enhancement of th1-biased protective immunity against avian influenza h9n2 virus via oral co-administration of attenuated salmonella enterica serovar typhimurium expressing chicken interferon-α and interleukin-18 along with an inactivated vaccine.control of currently circulating re-assorted low-pathogenicity avian influenza (lpai) h9n2 is a major concern for both animal and human health. thus, an improved lpai h9n2 vaccination strategy is needed to induce complete immunity in chickens against lpai h9n2 virus strains. cytokines play a crucial role in mounting both the type and extent of an immune response generated following infection with a pathogen or after vaccination. to improve the efficacy of inactivated lpai h9n2 vaccine, attenuate ...201222776696
differential modulation of intracellular survival of cytosolic and vacuolar pathogens by curcumin.curcumin, a principal component of turmeric, acts as an immunomodulator regulating the host defenses in response to a diseased condition. the role of curcumin in controlling certain infectious diseases is highly controversial. it is known to alleviate symptoms of helicobacter pylori infection and exacerbate that of leishmania infection. we have evaluated the role of curcumin in modulating the fate of various intracellular bacterial pathogens. we show that pretreatment of macrophages with curcumi ...201222890770
the mammalian microrna response to bacterial infections.micrornas are small rnas that post-transcriptionally regulate eukaryotic gene expression. in addition to their involvement in a wide range of physiological and pathological processes, including viral infections, micrornas are increasingly implicated in the eukaryotic response to bacterial pathogens. recent studies have characterized changes in host microrna expression following infection with exclusively extracellular (helicobacter pylori) or intracellular (salmonella enterica) gram-negative bac ...201222664920
construction and immunological evaluation of dual cell surface display of hiv-1 gag and salmonella enterica serovar typhimurium flic in lactobacillus acidophilus for vaccine delivery.oral vaccines that elicit a mucosal immune response may be effective against human immunodeficiency virus type 1 (hiv-1) because its transmission occurs mainly at the mucosa. the aim of this study was to construct recombinant lactobacillus for oral delivery of oral vaccines against hiv-1 and to evaluate their immunogenicity. a recombinant lactobacillus acidophilus strain expressing the hiv-1 gag on the bacterial cell surface was established by fusion with the signal peptide and anchor motif of a ...201222761297
enhanced influenza virus-like particle vaccines containing the extracellular domain of matrix protein 2 and a toll-like receptor ligand.the extracellular domain of matrix protein 2 (m2e) is conserved among influenza a viruses. the goal of this project is to develop enhanced influenza vaccines with broad protective efficacy using the m2e antigen. we designed a membrane-anchored fusion protein by replacing the hyperimmunogenic region of salmonella enterica serovar typhimurium flagellin (flic) with four repeats of m2e (4.m2e-tflic) and fusing it to a membrane anchor from influenza virus hemagglutinin (ha). the fusion protein was in ...201222647270
tigecycline challenge triggers srna production in salmonella enterica serovar typhimurium.bacteria employ complex transcriptional networks involving multiple genes in response to stress, which is not limited to gene and protein networks but now includes small rnas (srnas). these regulatory rna molecules are increasingly shown to be able to initiate regulatory cascades and modulate the expression of multiple genes that are involved in or required for survival under environmental challenge. despite mounting evidence for the importance of srnas in stress response, their role upon antibi ...201222958399
mitsuokella jalaludinii inhibits growth of salmonella enterica serovar typhimurium.salmonella continues to be a significant human health threat, and the objective of this study was to identify microorganisms with the potential to improve porcine food-safety through their antagonism of salmonella. anaerobic culture supernatants of 973 bacterial isolates from the gastrointestinal tract and feces of swine were screened for their capacity to inhibit the growth of salmonella enterica serovar typhimurium. growth inhibition of 1000-fold or greater was observed from 16 isolates, and 1 ...201222503601
effects of x-ray treatments on pathogenic bacteria, inherent microflora, color, and firmness on whole cantaloupe.inactivation of inoculated escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri on whole cantaloupes using x-ray at different doses (0.1, 0.5, 1.0, 1.5, and 2.0 kgy) was studied. the effect of x-ray on quality parameters (color and texture) of untreated and treated whole cantaloupes was instrumentally determined. the effect of x-ray on microflora counts (mesophilic counts, psychrotrophic counts and yeast and mold counts) of untreated and treated whole canta ...201222560020
sanitation of selected ready-to-eat intermediate-moisture foods of animal origin by e-beam irradiation.to optimize the sanitation treatment of ready-to-eat (rte) intermediate-moisture foods (imf), the behavior of listeria monocytogenes scott a (cip 103575), l. innocua (ntc 11288), salmonella enterica serovar typhimurium (cect 443), and escherichia coli o157:h7 (cect 4972) following treatment with electron-beam irradiation has been studied. as food matrixes, three rte vacuum-packed products (iberian dry-cured ham, dry beef [cecina], and smoked tuna) were used. although an irradiation treatment is ...201222551071
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
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
antimicrobial activity of lauric arginate-coated polylactic acid films against listeria monocytogenes and salmonella typhimurium on cooked sliced ham.a novel type of environmentally friendly packaging with antibacterial activity was developed from lauric arginate (lae)-coating of polylactic acid (pla) films after surface activation using a corona discharge. scanning electron microscopy (sem)-based analysis of the lae/pla films confirmed the successful coating of lae on the pla surface. the mechanical properties of the lae/pla films with different levels of lae-coating (0% to 2.6%[w/w]) were essentially the same as those of the neat pla film. ...201222309353
effect of storage temperature on survival and growth of foodborne pathogens on whole, damaged, and internally inoculated jalapeños (capsicum annuum var. annuum).there is a lack of general knowledge regarding the behavior of foodborne pathogenic bacteria associated with jalapeño peppers. the survival and growth behaviors of listeria monocytogenes, escherichia coli o157:h7, and salmonella enterica on the interior and exterior of jalapeño peppers were determined under different storage conditions. jalapeños were inoculated with a five-strain cocktail of l. monocytogenes, e. coli o157:h7, or s. enterica on the intact external surface, injured external surfa ...201222289602
survival of salmonella enterica, escherichia coli o157:h7, and listeria monocytogenes on inoculated walnut kernels during storage.the survival of single strains or cocktails of salmonella, escherichia coli o157:h7, and listeria monocytogenes was evaluated on walnut kernels. kernels were separately inoculated with an aqueous preparation of the pathogens at 3 to 10 log cfu/g, dried for 7 days, and then stored at 23°c for 3 weeks to more than 1 year. a rapid decrease of 1 to greater than 4 log cfu/g was observed as the inoculum dried. in some cases, the time of storage at 23°c did not influence bacterial levels, and in other ...201222289584
modeling the growth rate and lag time of different strains of salmonella enterica and listeria monocytogenes in ready-to-eat lettuce.the growth parameters (growth rate, μ and lag time, λ) of three different strains each of salmonella enterica and listeria monocytogenes in minimally processed lettuce (mpl) and their changes as a function of temperature were modeled. mpl were packed under modified atmosphere (5% o₂, 15% co₂ and 80% n₂), stored at 7-30 °c and samples collected at different time intervals were enumerated for s. enterica and l. monocytogenes. growth curves and equations describing the relationship between μ and λ ...201222265311
effect of x-ray treatments on pathogenic bacteria, inherent microbiota, color, and texture on parsley leaves.this work is a part of systematic studies of the effect of x-ray treatments on fresh produce. the main objective of this investigation was to study the effects of x-ray treatments in reducing the concentration of artificially inoculated escherichia coli o157:h7, listeria monocytogenes, salmonella enterica, and shigella flexneri, and inherent microbiota on parsley leaves. the secondary objective was to study the effects of x-ray treatments on color and texture parameters on treated parsley leaves ...201223035726
annual cost of illness and quality-adjusted life year losses in the united states due to 14 foodborne pathogens.in this article we estimate the annual cost of illness and quality-adjusted life year (qaly) loss in the united states caused by 14 of the 31 major foodborne pathogens reported on by scallan et al. (emerg. infect. dis. 17:7-15, 2011), based on their incidence estimates of foodborne illness in the united states. these 14 pathogens account for 95 % of illnesses and hospitalizations and 98 % of deaths due to identifiable pathogens estimated by scallan et al. we estimate that these 14 pathogens caus ...201222980013
filter-based pathogen enrichment technology for detection of multiple viable foodborne pathogens in 1 day.conventional foodborne pathogen assays currently used in the food industry often require long culture enrichments to increase pathogen levels so they can be detected. even using sensitive real-time pcr assays, culture enrichment at least overnight is necessary especially for detection of pathogens with slow growth rates such as listeria monocytogenes. to eliminate this cumbersome enrichment step and detect minute amounts of pathogens within 1 day, filter-based pathogen enrichment technology was ...201222947467
on the different growth conditions affecting silver antimicrobial efficacy on listeria monocytogenes and salmonella enterica.silver is known to inhibit microorganisms and therefore it is an ideal candidate for its incorporation in a wide variety of materials for food applications. however, there is still a need for understanding how silver prolonged exposure to bacterial contamination affects the bioavailability of the active silver species. in the present study, growth curves of listeria monocytogenes and salmonella enterica were performed for 3-5 days in tryptic soy broth (tsb) and m9 minimal medium (m9) in the pres ...201222835228
reduction in resident microflora, and experimentally inoculated salmonella enterica, on spinach leaves treated with vinegar and canola oil.in this study, we explored the use of vinegar, or vinegar and canola oil as a salad dressing, to reduce bacterial levels on spinach leaves. we found that incubation of spinach leaves with various types of vinegar substantially reduced the predominantly gram-negative microflora. a similar response was observed when spinach leaves were incubated with white vinegar mixed in various proportions with canola oil, as used in salad dressing. we assessed the effects of vinegar, or vinegar and oil, on spi ...201222828283
evaluation of near-infrared pasteurization in controlling escherichia coli o157:h7, salmonella enterica serovar typhimurium, and listeria monocytogenes in ready-to-eat sliced ham.this study was conducted to investigate the efficacy of near-infrared (nir) heating to reduce salmonella enterica serovar typhimurium, escherichia coli o157:h7, and listeria monocytogenes in ready-to-eat (rte) sliced ham compared to conventional convective heating, and the effect of nir heating on quality was determined by measuring the color and texture change. a cocktail of three pathogens was inoculated on the exposed or protected surfaces of ham slices, followed by nir or conventional heatin ...201222773635
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
transcriptome mapping of par060302, a blacmy-2-positive broad-host-range inca/c plasmid.the multidrug resistance-encoding plasmids belonging to the inca/c incompatibility group have recently emerged among escherichia coli and salmonella enterica strains in the united states. these plasmids have a unique genetic structure compared to other enterobacterial plasmid types, a broad host range, and a propensity to acquire large numbers of antimicrobial resistance genes via their accessory regions. using e. coli strain dh5α harboring the prototype inca/c plasmid par060302, we sought to de ...201222344651
dynamics of salmonella small rna expression in non-growing bacteria located inside eukaryotic cells.small non-coding regulatory rnas (srnas) have been studied in many bacterial pathogens during infection. however, few studies have focused on how intracellular pathogens modulate srna expression inside eukaryotic cells. here, we monitored expression of all known srnas of salmonella enterica serovar typhimurium (s. typhimurium) in bacteria located inside fibroblasts, a host cell type in which this pathogen restrains growth. srna sequences known in s. typhimurium and escherichia coli were searched ...201222336761
role of anionic charges of osmoregulated periplasmic glucans of salmonella enterica serovar typhimurium sl1344 in mice virulence.opgb gene of salmonella enterica serovar typhimurium was identified earlier in a genome-wide screen for mice virulence (valentine et al. in infect immun 66:3378-3383, 1998). although mutation in opgb resulted in avirulent salmonella strain, how this gene contributes to pathogenesis remains unclear. based on dna homology, opgb is predicted to be responsible for adding phosphoglycerate residues to osmoregulated periplasmic glucans (opgs) giving them anionic characteristics. in escherichia coli, ye ...201222278765
pathogenic and multidrug-resistant escherichia fergusonii from broiler chicken.an escherichia spp. isolate, ecd-227, was previously identified from the broiler chicken as a phylogenetically divergent and multidrug-resistant escherichia coli possessing numerous virulence genes. in this study, whole genome sequencing and comparative genome analysis was used to further characterize this isolate. the presence of known and putative antibiotic resistance and virulence open reading frames were determined by comparison to pathogenic (e. coli o157:h7 tw14359, apec o1:k1:h7, and upe ...201222252367
carriage of antibiotic-resistant enteric bacteria varies among sites in galapagos reptiles.increased overlap between humans and wildlife populations has increased the risk for novel disease emergence. detecting contacts with a high risk for transmission of pathogens requires the identification of dependable measures of microbial exchange. we evaluated antibiotic resistance as a molecular marker for the intensity of human-wildlife microbial connectivity in the galápagos islands. we isolated escherichia coli and salmonella enterica from the feces of land iguanas (conolophus sp.), marine ...201222247374
gut inflammation can boost horizontal gene transfer between pathogenic and commensal enterobacteriaceae.the mammalian gut harbors a dense microbial community interacting in multiple ways, including horizontal gene transfer (hgt). pangenome analyses established particularly high levels of genetic flux between gram-negative enterobacteriaceae. however, the mechanisms fostering intraenterobacterial hgt are incompletely understood. using a mouse colitis model, we found that salmonella-inflicted enteropathy elicits parallel blooms of the pathogen and of resident commensal escherichia coli. these blooms ...201222232693
arginine 66 residue of fur is required for the regulatory function of this protein in the acid adaptation mechanism of helicobacter pylori.helicobacter pylori colonizes the gastric mucosa and must survive the acid ph of that environment. like other enteric bacterial pathogens, including salmonella enterica, h. pylori develops an acid tolerance response that is dependent on the function of the transcriptional regulator protein fur.201222221611
improved immune responses against avian influenza virus following oral vaccination of chickens with ha dna vaccine using attenuated salmonella typhimurium as carrier.this study evaluates the immune responses of single avian influenza virus (aiv) ha dna vaccine immunization using attenuated salmonella enterica sv. typhimurium as an oral vaccine carrier and intramuscular (im) dna injection. one-day-old specific-pathogen-free (spf) chicks immunized once by oral gavage with 10(9) salmonella colony-forming units containing plasmid expression vector encoding the ha gene of a/ck/malaysia/5858/04 (h5n1) (pcdna3.1.h5) did not show any clinical manifestations. serum h ...201222512819
structural characterization of the h-ns protein from xylella fastidiosa and its interaction with dna.the nucleoid-associated protein h-ns is a major component of the bacterial nucleoid involved in dna compaction and transcription regulation. the nmr solution structure of the xylella fastidiosa h-ns c-terminal domain (residues 56-134) is presented here and consists of two beta-strands and two alpha helices, with one loop connecting the two beta-strands and a second loop connecting the second beta strand and the first helix. the amide (1)h and (15)n chemical shift signals for a sample of xfh-ns(5 ...201222772065
differential expression of the transcription factors mara, rob, and soxs of salmonella typhimurium in response to sodium hypochlorite: down-regulation of rob by mara and soxs.to survive, salmonella enterica serovar typhimurium (s. typhimurium) must sense signals found in phagocytic cells and modulate gene expression. in the present work, we evaluated the expression and cross-regulation of the transcription factors mara, rob, and soxs in response to naocl. we generated strains δsoxs and δmara, which were 20 times more sensitive to naocl as compared to the wild-type strain; while δrob only 5 times. subsequently, we determined that mara and soxs transcript and protein l ...201222752112
construction of recombinant e. coli nissle 1917 (ecn) strains for the expression and secretion of defensins.the probiotic escherichia coli strain nissle 1917 (ecn) is one of the few probiotics licensed as a medication in several countries. best documented is its effectiveness in keeping patients suffering from ulcerative colitis (uc) in remission. this might be due to its ability to induce the production of human β-defensin 2 (hbd2) in a flagellin-dependent way in intestinal epithelial cells. in contrast to ulcerative colitis, for crohn's disease (cd) convincing evidence is lacking that ecn might be c ...201222748509
traditional copper water storage vessels and sub-lethal injury of salmonella enterica serovar typhi and vibrio cholerae.recent studies on escherichia coli have demonstrated sub-lethal injury-sensitivity to oxygen and selective agents prior to irreversible inactivation when kept in water in a brass vessel. the present study was carried out to investigate whether equivalent responses occur in copper vessels using the pathogens salmonella enterica serovar typhi and vibrio cholerae. bacterial suspensions were stored in water in a traditional copper vessel for up to 24 h at 30 °c. samples were withdrawn and plated on ...201222717752
scano-magneto immunoassay based on carbon nanotubes/gold nanoparticles nanocomposite for salmonella enterica serovar typhimurium detection.to improve sensitivity of s. enterica serovar typhimurium detection, multiwalled carbon nanotubes (mwcnts) and gold nanoparticles (aunps) were combined and used as a label to amplify signal in a scanometric based assay. in this study, the mwcnts/aunps nanocomposite was fabricated by directly assemble of au(3+) to mwcnts and allowed growing of aunps along the mwcnts surface. this mwcnts/aunps nanocomposite was then attached to anti-s. typhimurium antibody (mwcnts/aunps/ab(1)) and used as a detect ...201222705403
the application of stem and in situ controlled dehydration to bacterial systems using esem.transmission imaging with an environmental scanning electron microscope (esem) (wet stem) is a recent development in the field of electron microscopy, combining the simple preparation inherent to esem work with an alternate form of contrast available through a stem detector. because the technique is relatively new, there is little information available on how best to apply this technique and which samples it is best suited for. this work is a description of the sample preparation and microscopy ...201222689513
receptor-independent interaction of bacterial lipopolysaccharide with lipid and lymphocyte membranes; the role of cholesterol.lipopolysaccharide (lps) is a major constituent of bacterial outer membranes where it makes up the bulk of the outer leaflet and plays a key role as determinant of bacterial interactions with the host. membrane-free lps is known to activate t-lymphocytes through interactions with toll-like receptor 4 via multiprotein complexes. in the present study, we investigate the role of cholesterol and membrane heterogeneities as facilitators of receptor-independent lps binding and insertion, which underpi ...201222685597
impact of hfq on the intrinsic drug resistance of salmonella enterica serovar typhimurium.salmonella enterica is an important enteric pathogen, and its various serovars cause both systemic and intestinal diseases in humans and domestic animals. the emergence of multidrug-resistant strains of salmonella, leading to increased morbidity and mortality, has further complicated its management. hfq is an rna chaperon that mediates the binding of small rnas to mrna and assists in post-transcriptional gene regulation in bacteria. although hfq is related to important phenotypes including virul ...201222675323
antibiotic resistance of salmonella enterica serovar typhi in kolkata, india, and in vitro experiments on effect of combined chemotherapy.this communication states the changing patterns of salmonella enterica serovar typhi (s. typhi) isolates causing enteric fever in and around kolkata, india. among the isolates resistance to ampicillin (a), chloramphenicol (c), cotrimoxazole (co) and tetracycline (t) were plasmid mediated; the plasmid was unstable in s. typhi, and the other enteric bacteria like escherichia coli, klebsiella pneumoniae and proteus vulgaris were found to be the potential source of dissemination of such plasmids int ...201222666124
antimicrobial food packaging film based on the release of lae from evoh.the aim of this work was to develop antimicrobial films for active packaging applications containing the natural antimicrobial compound lae (lauramide arginine ethyl ester) in evoh copolymers with different mol % ethylene contents (i.e. evoh-29 and evoh-44). evoh-29 and evoh-44 films were made by casting and incorporating 0.25%, 1%, 5%, and 10% lae in the film forming solution (w/w with respect to polymer weight). previously, the minimum inhibitory concentration (mic) and the minimum bactericida ...201222640726
development of antimicrobial films for microbiological control of packaged salad.the aim of the present work was to characterize the antimicrobial efficiency of films consisting of pp/evoh structures with oregano essential oil and citral. both substances are known for their antimicrobial activity based on their interaction with the cell membrane. the films developed were used to pack minimally processed salads, combining modified atmosphere technology to extend shelf-life and active packaging technology to reduce possible microbiological risks. the antimicrobial activity of ...201222633535
community-acquired bacterial bloodstream infections in developing countries in south and southeast asia: a systematic review.information about community-acquired bacteraemia in developing countries in south and southeast asia is scarce. we aimed to establish the case fraction of bacteraemia in febrile patients admitted to hospital. we searched four databases and identified studies of south and southeast asia published between 1990 and 2010 that prospectively assessed patients admitted to hospital and from whom a blood culture was taken. we reviewed 17 eligible studies describing 40,644 patients. pathogenic organisms w ...201222632186
effects of indole on drug resistance and virulence of salmonella enterica serovar typhimurium revealed by genome-wide analyses.many gram-positive and gram-negative bacteria produce large quantities of indole as an intercellular signal in microbial communities. indole demonstrated to affect gene expression in escherichia coli as an intra-species signaling molecule. in contrast to e. coli, salmonella does not produce indole because it does not harbor tnaa, which encodes the enzyme responsible for tryptophan metabolism. our previous study demonstrated that e. coli-conditioned medium and indole induce expression of the acra ...201222632036
the acyl homoserine lactone receptor, sdia, of escherichia coli and salmonella enterica serovar typhimurium does not respond to indole.in this study, we tested the hypothesis that the sdia proteins of escherichia coli and salmonella enterica serovar typhimurium respond to indole. while indole was found to have effects on gene expression and biofilm formation, these effects were not sdia dependent. however, high concentrations of indole did inhibit n-acyl-l-homoserine lactone (ahl) sensing by sdia. we conclude that sdia does not respond to indole but indole can inhibit sdia activity in e. coli and salmonella.201222610437
instability of escherichia coli r-factors in salmonella enterica serovar typhi involves formation of recombinant composite plasmid structures.in spite of a well-documented ability of samonella enterica typhi strains to receive r factors from escherichia coli and other enterobacteria, epidemiological data show that typhi is a rather poor host of antibiotic-resistance genes and in fact, of plasmids, suggesting that most of the plasmids naturally acquired by typhi strains become unstable and eventually segregate. we have previously reported evidence that each of three plasmids conjugatively transferred to s. enterica typhi experienced de ...201222579995
c1 inhibitor suppresses the endotoxic activity of a wide range of lipopolysaccharides and interacts with live gram-negative bacteria.human c1 inhibitor (c1inh) prevents endotoxin shock via a direct interaction with gram-negative bacterial lipopolysaccharide (lps) and improves survival in animal models of sepsis. in this report, we further characterize the interaction of c1inh with lps and whole live bacteria. we investigate c1inh interactions with lps from five different strains of gram-negative enteric bacteria known to participate in the pathogenesis of human sepsis. treatment with c1inh improved survival in mice with endot ...201222576004
characterization of salmonella enterica and detection of the virulence genes specific to diarrheagenic escherichia coli from poultry carcasses in ouagadougou, burkina faso.one hundred chicken carcasses purchased from three markets selling poultry in ouagadougou, burkina faso, between june 2010 and october 2010 were examined for their microbiological quality. the presence of salmonella was investigated using standard bacteriological procedures, and the isolates obtained were serotyped and tested for antimicrobial susceptibility. the presence of virulence-associated genes of the five main pathogroups of diarrheagenic escherichia coli-shiga toxin-producing e. coli (s ...201222551070
conversion of viable but nonculturable enteric bacteria to culturable by co-culture with eukaryotic cells.viable but nonculturable (vbnc) vibrio cholerae non-o1/non-o139, v. parahaemolyticus, enterohemorrhagic escherichia coli, enterotoxigenic e. coli, enteropathogenic e. coli, shigella flexneri, and salmonella enterica were converted to the culturable state by co-culture with selected eukaryotic cells, e.g., ht-29, caco-2, t84, hela, intestine 407, and cho cells.201222537150
variability of rna quality extracted from biofilms of foodborne pathogens using different kits impacts mrna quantification by qpcr.the biofilm formation by foodborne pathogens is known to increase the problem related with surface disinfection procedure in the food processing environment and consequent transmission of these pathogens into the population. messenger rna has been increasingly used to understand the action and the consequences of disinfectants in the virulence on such biofilms. rna quality is an important requirement for any rna-based analysis since the quality can impair the mrna quantification. therefore, we e ...201222526569
antioxidant and antibacterial activities of the leaf essential oil and its constituents furanodienone and curzerenone from lindera pulcherrima (nees.) benth. ex hook. f.lindera pulcherrima (nees.) benth. ex hook. f. (family: lauraceae), an evergreen shrub, is an important medicinal plant distributed in temperate himalayan regions. the leaves and bark are used as spice in cold, fever, and cough.201222518079
detection and characterization of pct-like plasmid vectors for blactx-m-14 in escherichia coli isolates from humans, turkeys and cattle in england and wales.to detect and characterize escherichia coli strains and pct-like plasmids implicated in the dissemination of the ctx-m-14 gene in animals and humans, in england and wales.201222514265
the missing link in coenzyme a biosynthesis: panm (formerly yhhk), a yeast gcn5 acetyltransferase homologue triggers aspartate decarboxylase (pand) maturation in salmonella enterica.coenzyme a (coa) is an essential cofactor for all forms of life. the biochemistry underpinning the assembly of coa in escherichia coli and other enterobacteria is well understood, except for the events leading to maturation of the l-aspartate-α-decarboxylase (pand) enzyme that converts pantothenate to β-alanine. pand is synthesized as pro-pand, which undergoes an auto-proteolytic cleavage at residue ser25 to yield the catalytic pyruvoyl moiety of the enzyme. since 1990, it has been known that e. ...201222497218
salmonella chemoreceptors mcpb and mcpc mediate a repellent response to l-cystine: a potential mechanism to avoid oxidative conditions.chemoreceptors mcpb and mcpc in salmonella enterica have been reported to promote chemotaxis in lb motility-plate assays. of the chemicals tested as potential effectors of these receptors, the only response was towards l-cysteine and its oxidized form, l-cystine. although enhanced radial migration in plates suggested positive chemotaxis to both amino acids, capillary assays failed to show an attractant response to either, in cells expressing only these two chemoreceptors. in vivo fluorescence re ...201222486902
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
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
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
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
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
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
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
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
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
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
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
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
mobile effector proteins on phage genomes.bacteriophage genomes found in a range of bacterial pathogens encode a diverse array of virulence factors ranging from superantigens or pore forming lysins to numerous exotoxins. recent studies have uncovered an entirely new class of bacterial virulence factors, called effector proteins or effector toxins, which are encoded within phage genomes that reside among several pathovars of escherichia coli and salmonella enterica. these effector proteins have multiple domains resulting in proteins that ...201223275865
a novel target of iscs in escherichia coli: participating in dna phosphorothioation.many bacterial species modify their dna with the addition of sulfur to phosphate groups, a modification known as dna phosphorothioation. dnda is known to act as a cysteine desulfurase, catalyzing a key biochemical step in phosphorothioation. however, bioinformatic analysis revealed that 19 out of the 31 known dnd gene clusters, contain only four genes (dndb-e), lacking a key cysteine desulfurase corresponding gene. there are multiple cysteine desulfurase genes in escherichia coli, but which one ...201223240007
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
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
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
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
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
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
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
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
evolution of transcriptional regulation in closely related bacteria.the exponential growth of the number of fully sequenced genomes at varying taxonomic closeness allows one to characterize transcriptional regulation using comparative-genomics analysis instead of time-consuming experimental methods. a transcriptional regulatory unit consists of a transcription factor, its binding site and a regulated gene. these units constitute a graph which contains so-called "network motifs", subgraphs of a given structure. here we consider genomes of closely related enteroba ...201223039862
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