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fungal and bacterial killing by neutrophils.neutrophils are professional phagocytes of the innate immune system that are essential to control bacterial and fungal infections. these cells engulf and kill invading microbes. additionally, activated neutrophils are able to release neutrophil extracellular traps (nets). these fibers consist of chromatin decorated with antimicrobial proteins to trap and kill microbes. appropriate quantitative methods are required to understand the nature of interactions of neutrophils with pathogens. here we pr ...200919089391
extensive antibody cross-reactivity among infectious gram-negative bacteria revealed by proteome microarray analysis.antibodies provide a sensitive indicator of proteins displayed by bacteria during sepsis. because signals produced by infection are naturally amplified during the antibody response, host immunity can be used to identify biomarkers for proteins that are present at levels currently below detectable limits. we developed a microarray comprising approximately 70% of the 4066 proteins contained within the yersinia pestis proteome to identify antibody biomarkers distinguishing plague from infections ca ...200919112181
antimicrobial activity of prulifloxacin tested against a worldwide collection of gastroenteritis-producing pathogens, including those causing traveler's diarrhea.prulifloxacin, the prodrug of ulifloxacin (active component), is a newer fluoroquinolone with broad activity against enteric and nonenteric gram-negative bacilli. ulifloxacin and other oral comparator agents were tested for activity against 582 gastroenteritis strains from global surveillance studies. ulifloxacin was highly active against escherichia coli, salmonella spp., shigella spp., yersinia spp., vibrio spp., aeromonas spp., and plesiomonas spp. (mic(50)s and mic(90)s, <or=0.03 microg/ml a ...200919114678
diagnosis and prevalence of enteropathogenic bacteria in children less than 5 years of age with acute diarrhea in tehran children's hospitals.acute diarrhea disease is the second cause of death among all infectious diseases in children younger than 5 years of age worldwide. the aim of this study was to employ a combination of biochemical, microbiological and molecular diagnostic techniques to investigate the stools of iranian children with acute diarrhea for bacterial enteropathogens.200919117609
bacterial particle endocytosis by epithelial cells is selective and enhanced by tumor necrosis factor receptor ligands.bacterial pathogens use virulence strategies to invade epithelial barriers, but active processes of epithelial cells may also contribute to the endocytosis of microbial particles. to focus on the latter, we studied the uptake of fixed and fluorescently labeled bacterial particles in intestinal and bronchoepithelial cell cultures and found it to be enhanced in caco-2bbe and nci-h292 cells after treatment with tumor necrosis factor alpha and an agonist antibody against the lymphotoxin beta recepto ...200919129472
genetics and environmental regulation of shigella iron transport systems.shigella spp. have transport systems for both ferric and ferrous iron. the iron can be taken up as free iron or complexed to a variety of carriers. all shigella species have both the feo and sit systems for acquisition of ferrous iron, and all have at least one siderophore-mediated system for transport of ferric iron. several of the transport systems, including sit, iuc/iuta (aerobactin synthesis and transport), fec (ferric di-citrate uptake), and shu (heme transport) are encoded within pathogen ...200919130265
outbreaks of shigella sonnei infections in denmark and australia linked to consumption of imported raw baby corn.we investigated an outbreak of shigella sonnei infections in denmark and australia associated with imported baby corn from one packing shed in thailand. we reviewed nationwide surveillance and undertook case finding, food trace-back and microbiological investigation of human, food and environmental samples. a recall of baby corn and sugar snaps was based on descriptive epidemiological evidence. in denmark, we undertook a retrospective cohort study in one workplace. in total, 215 cases were labor ...200919134229
frequency of isolation of various subtypes and antimicrobial resistance of shigella from urban slums of karachi, pakistan.shigellosis remains a major public health problem in developing countries. antimicrobial resistance has complicated the empirical treatment. knowledge of serotypes is crucial in vaccine development, as cross-protection between various serotypes is limited. therefore we conducted a prospective study to determine the frequency of isolation of shigella serotypes and antimicrobial resistance.200919135399
safety and immunogenicity of sc599, an oral live attenuated shigella dysenteriae type-1 vaccine in healthy volunteers: results of a phase 2, randomized, double-blind placebo-controlled trial.sc599 vaccine is a live shigella dysenteriae 1 strain attenuated by deletion of invasion [icsa], iron chelation [ent, fep] and shiga toxin a subunit [stxa] genes. in a preliminary phase 1 single dose prospective study, we showed that sc599 vaccine was well tolerated, and the maximum tolerable dose was greater than 10(8) cfu [sadorge c, ndiaye a, beveridge n, frazer s, giemza r, jolly n, et al. phase 1 clinical trial of live attenuated shigella dysenteriae type-1 deltaicsa deltaent deltafep delta ...200919135496
trends in antimicrobial resistance of fecal shigella and salmonella isolates in tehran, iran.the resistance of bacteria to commonly prescribed antibiotics is increasing both in developing as well as developed countries. resistance has emerged even to newer, more potent antimicrobial agents. the present study was therefore undertaken to report resistance rates to antimicrobial agents in 2487 stool culture isolates in a tertiary care hospital between 1996 and 2000 and 2001 and 2005.200919136781
functions and pathologies of bip and its interaction partners.the endoplasmic reticulum (er) is involved in a variety of essential and interconnected processes in human cells, including protein biogenesis, signal transduction, and calcium homeostasis. the central player in all these processes is the er-lumenal polypeptide chain binding protein bip that acts as a molecular chaperone. bip belongs to the heat shock protein 70 (hsp70) family and crucially depends on a number of interaction partners, including co-chaperones, nucleotide exchange factors, and sig ...200919151922
overexpression, purification, characterization and preliminary crystallographic study of phosphoglycolate phosphatase from shigella flexneri 2a strain 301.phosphoglycolate phosphatase has a salvage function in the metabolism of the 2-phosphoglycolate formed during bacterial dna repair. in order to better understand its dimerization behaviour, the influence of metal ions on its activity and its catalytic mechanism at the molecular level, recombinant phosphoglycolate phosphatase from shigella flexneri was overexpressed, purified, characterized and crystallized by the hanging-drop vapour-diffusion method at 291 k using polyethylene glycol 3500 as a p ...200919153451
simultaneous detection of multifood-borne pathogenic bacteria based on functionalized quantum dots coupled with immunomagnetic separation in food samples.this paper reports a method that simultaneously detects three food-borne pathogenic bacteria, salmonella typhimurium, shigella flexneri, and escherichia coli o157:h7, via an approach that combines magnetic microparticles for the enrichment and antibody-conjugated semiconductor quantum dots (qds) as fluorescence markers. using the water-in-oil reverse microemulsions method, the gamma-fe(2)o(3) magnetic nanoparticles were coated with silica to empower the particles with high dispersibility and bro ...200919154162
shigella type iii secretion effectors: how, where, when, for what purposes?bacteria of shigella spp., the causative agents of shigellosis in humans, possess a repertoire of approximately 25-30 effectors injected into host cells by a type iii secretion apparatus (t3sa). the t3sa activity is activated upon contact of bacteria with cells and controls expression of some effectors. recent structural and functional studies suggest that two different sets of effectors are involved in inducing actin cytoskeleton reorganization to promote entry of bacteria into epithelial cells ...200919157960
rapid dna amplification using a battery-powered thin-film resistive thermocycler.a prototype handheld, compact, rapid thermocycler was developed for multiplex analysis of nucleic acids in an inexpensive, portable configuration. instead of the commonly used peltier heating/cooling element, electric thin-film resistive heater and a miniature fan enable rapid heating and cooling of glass capillaries leading to a simple, low-cost thin-film resistive thermocycler (tfrt). computer-based pulse width modulation control yields heating rates of 6-7 k/s and cooling rates of 5 k/s. the ...200919159110
organised genome dynamics in the escherichia coli species results in highly diverse adaptive paths.the escherichia coli species represents one of the best-studied model organisms, but also encompasses a variety of commensal and pathogenic strains that diversify by high rates of genetic change. we uniformly (re-) annotated the genomes of 20 commensal and pathogenic e. coli strains and one strain of e. fergusonii (the closest e. coli related species), including seven that we sequenced to completion. within the approximately 18,000 families of orthologous genes, we found approximately 2,000 comm ...200919165319
the ipac carboxyterminal effector domain mediates src-dependent actin polymerization during shigella invasion of epithelial cells.shigella, the causative agent of bacillary dysentery, invades epithelial cells by locally reorganizing the actin cytoskeleton. shigella invasion requires actin polymerization dependent on the src tyrosine kinase and a functional bacterial type iii secretion (t3s) apparatus. using dynamic as well as immunofluorescence microscopy, we show that the t3s translocon component ipac allows the recruitment of the src kinase required for actin polymerization at bacterial entry sites during the initial sta ...200919165331
phage-mediated shiga toxin 2 gene transfer in food and water.shiga toxin (stx) transduction in various food matrices has been evaluated with lysogens of stx phages. stx transduction events were observed for many phages under appropriate conditions. transduction did not occur at low ph and low temperatures. a total of 10(3) to 10(4) cfu ml(-1) was the minimal amount of donor and recipient strains necessary to generate transductants.200919168651
short report: high prevalence of serine protease autotransporter cytotoxins among strains of enteroaggregative escherichia coli.enteroaggregative escherichia coli (eaec) pathogenesis is thought to comprise intestinal colonization followed by the release of enterotoxins and cytotoxins. here, we use a polymerase chain reaction (pcr) to determine the prevalence of 10 genes encoding serine protease autotransporter toxins (spates) in a collection of clinical eaec isolates. eighty-six percent of eaec strains harbored genes encoding one or more class i cytotoxic spate proteins (pet, sat, espp, or siga). two class ii, non-cytoto ...200919190229
molecular epidemiological characteristics of shigella spp. isolated from river narmada during 2005-2006.shigellosis is an acute gastroenteritis caused by shigella species. forty isolates of shigella spp. were obtained from the river narmada during 2005-2006. twenty-three isolates were identified as s. flexneri, 10 as s. sonnei, and seven as s. dysenteriae on the basis of biochemical tests and serotyping. all the isolates harbored at least one plasmid (range: 1-4) and exhibited 12 distinct plasmid profile patterns. out of 40 isolates, 90% were found to be resistant against more than two antibiotics ...200919192746
crystal structure analysis and in silico pka calculations suggest strong pka shifts of ligands as driving force for high-affinity binding to tgt.a novel ligand series is presented to inhibit trna-guanine transglycosylase (tgt), a protein with a significant role in the pathogenicity mechanism of shigella flexneri, the causative agent of shigellosis. the enzyme exchanges guanine in the wobble position of trna(asn,asp,his,tyr) against a modified base. to prevent the base-exchange reaction, several series of inhibitors have already been designed, synthesized, and tested. one aim of previous studies was to address a hydrophobic pocket with di ...200919199329
streptococcus-, shigella-, and listeria-induced autophagy.autophagy has recently been described as an intrinsic host defense system for recognizing and eliminating intracellular-invading bacterial pathogens. some cytoplasmic-invading bacteria are trapped through the process of autophagy and are ultimately degraded within autolysosomal compartments. however, others exhibit highly evolved maneuvers for circumventing autophagic recognition and are capable of surviving and replicating within the cytoplasm. in this chapter, we describe bacterial infectious ...200919200893
a synthetic carbohydrate-protein conjugate vaccine candidate against shigella flexneri 2a infection.the protective ag of shigella, the gram-negative enteroinvasive bacterium causing bacillary dysentery, or shigellosis, is its o-specific polysaccharide (o-sp) domain of the lps, the major bacterial surface component. as an alternative to the development of detoxified lps-based conjugate vaccines, recent effort was put into the investigation of neoglycoproteins encompassing synthetic oligosaccharides mimicking the protective ags of the o-sp. we previously reported that when coupled to tetanus tox ...200919201878
development of prophylactic recombinant hpv58-attenuated shigella live vector vaccine and evaluation of its protective efficacy and immunogenicity in the guinea pig keratoconjunctivitis model.to develop a prophylactic recombinant hpv58l1-attenuated shigella live vector vaccine and evaluate its protective efficacy and immunogenicity in the guinea pig keratoconjunctivitis model, the hpv58l1 gene was cloned into vector pucmt, and then subcloned into the suicide vector pcvd442. the recombinant plasmid pcvd442-hpv58l1 was introduced into attenuated shigella (sf301:deltavirg) with the helper plasmid prk2013 by filter mating. the positive colonies were harvested and confirmed by polymerase ...200919204831
the poultry red mite (dermanyssus gallinae): a potential vector of pathogenic agents.the poultry red mite, d. gallinae has been involved in the transmission of many pathogenic agents, responsible for serious diseases both in animals and humans. nowadays, few effective methods are available to control the ectoparasite in poultry farms. consequently, this is an emerging problem which must be taken into account to maintain good health in commercial egg production. this paper addresses the vector capacity of the ectoparasite with special emphasis on salmonellae, pathogenic agents re ...200919205905
pathogen trafficking pathways and host phosphoinositide metabolism.phosphoinositide (pi) glycerolipids are key regulators of eukaryotic signal transduction, cytoskeleton architecture and membrane dynamics. the host cell pi metabolism is targeted by intracellular bacterial pathogens, which evolved intricate strategies to modulate uptake processes and vesicle trafficking pathways. upon entering eukaryotic host cells, pathogenic bacteria replicate in distinct vacuoles or in the host cytoplasm. vacuolar pathogens manipulate pi levels to mimic or modify membranes of ...200919208094
a look back at an ongoing problem: shigella dysenteriae type 1 epidemics in refugee settings in central africa (1993-1995).shigella dysenteriae type 1 (sd1) is a cause of major dysentery outbreaks, particularly among children and displaced populations in tropical countries. although outbreaks continue, the characteristics of such outbreaks have rarely been documented. here, we describe the sd1 outbreaks occurring between 1993 and 1995 in 11 refugee settlements in rwanda, tanzania and democratic republic of the congo (drc). we also explored the links between the different types of the camps and the magnitude of the o ...200919214226
antimicrobial pentacyclic triterpenoids from terminalia superba.antibacterial bioassay-guided fractionation of the methanol extract of the stem bark of terminalia superba led to the isolation of four new triterpene glucosides (1-4) which were characterized as 2 alpha,3 beta-dihydroxyolean-12-en-28-oic acid 28-o-beta-d-glucopyranoside (1), 2 alpha,3 beta, 21 beta-trihydroxyolean-12-en-28-oic acid 28-o-beta-d-glucopyranoside (2), 2 alpha,3 beta, 29-trihydroxyolean-12-en-28-oic acid 28-o-beta-d-glucopyranoside (3) and 2 alpha,3 beta,23,27-tetrahydroxyolean-12-e ...200919214947
apyrase-based colorimetric test for detection of shigella and enteroinvasive escherichia coli in stool.for lack of simple inexpensive early detection methods for shigella spp. and enteroinvasive escherichia coli (eiec), bacillary dysentery remains a major cause of childhood mortality and morbidity in india and other developing countries. rapid stool testing for apyrase, a specific periplasmic enzyme essential for the pathogen's intracellular spread, may provide a solution. we have developed a whole-cell colorimetric pyrophosphate hydrolysis assay based on cheap, stable, and locally available reag ...200919216937
shigella targets the mitochondrial checkpoint of programmed necrosis.in nonmyeloid cells, shigella hijacks the mitochondrial checkpoint of cell death, thereby inducing a regulated form of necrosis depending on bnip3 and cyclophilin d. carneiro et al. (2009) describe the interplay between this program and a prosurvival response transmitted via the nod1/rip2/nf-kappab/bcl-2 axis, which determines the fate of infected cells.200919218080
shigella induces mitochondrial dysfunction and cell death in nonmyleoid cells.shigella rapidly kills myeloid cells via a caspase-1 inflammasome-dependent cell death mechanism. however, despite a critical role for nonmyeloid cells in the physiopathology of shigella infection, the mechanism by which shigella kills nonmyeloid cells remains uncharacterized. here we demonstrate that, in nonmyeloid cells, shigella infection induces loss of mitochondrial inner membrane potential, mitochondrial damage, and necrotic cell death through a pathway dependent on bnip3 and cyclophilin d ...200919218084
the 3'-to-5' exoribonuclease (encoded by hp1248) of helicobacter pylori regulates motility and apoptosis-inducing genes.the human gastric pathogen helicobacter pylori has many virulence factors involved in pathogenesis, but the mechanisms regulating these virulence factors are not yet fully understood. in this study, we cloned hp1248, which is similar in sequence to escherichia coli vacb, which was previously shown to be associated with the expression of virulence in shigella and enteroinvasive e. coli. e. coli vacb encodes rnase r. rnase r is involved in the posttranscriptional regulation of mrna stability. by g ...200919218383
the expression of lipopolysaccharide by strains of shigella dysenteriae, shigella flexneri and shigella boydii and their cross-reacting strains of escherichia coli.strains of shigella dysenteriae, shigella flexneri and shigella boydii express lipopolysaccharides, that enable the serotyping of strains based on their antigenic structures. certain strains of s. dysenteriae, s. flexneri and s. boydii are known to share epitopes with strains of escherichia coli; however, the lipopolysaccharide profiles of the cross-reacting organisms have not been compared by sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page) lipopolysaccharides profiling. in ...200919222579
[distribution and antibiotic resistance of pathogens isolated from children with infectious diarrhea in guangzhou].to study the distribution and antibiotic resistance of the isolated pathogens from children with infectious diarrhea in guangzhou.200919222945
mucosal adjuvanticity of a shigella invasin complex with dna-based vaccines.protection against many infectious diseases may require the induction of cell-mediated and mucosal immunity. immunization with plasmid dna-based vaccines has successfully induced cell-mediated immune responses in small animals but is less potent in humans. therefore, several methods are under investigation to augment dna vaccine immunogenicity. in the current study, a mucosal adjuvant consisting of an invasin protein-lipopolysaccharide complex (invaplex) isolated from shigella spp. was evaluated ...200919225079
utility of multilocus variable-number tandem-repeat analysis as a molecular tool for phylogenetic analysis of shigella sonnei.a panel of 916 isolates, including 703 closely related ist1 isolates, were characterized by inter-is1 spacer typing (ist), pulsed-field gel electrophoresis (pfge), and multilocus variable-number tandem-repeat (vntr) analysis (mlva) to evaluate the utility of mlva as a molecular tool for the phylogenetic analysis of shigella sonnei. the global phylogenetic patterns determined by ist, pfge, and mlva were concordant. mlva was carried out using 26 vntr loci with a range of degrees of variability. ml ...200919225095
eliminylation: a post-translational modification catalyzed by phosphothreonine lyases.we propose the classification of a protein post-translational modification, eliminylation, based on the recently delineated mechanism of the shigella ospf and salmonella spvc phosphothreonine lyases. these bacterial type-iii secretion-system virulence factors are injected into eukaryotic cells and inhibit signalling by irreversibly inactivating mitogen-activated protein kinases (mapks). remarkably, they employ an unusual beta-elimination reaction, removing the phosphate from phosphothreonine and ...200919233656
analytical specificity and sensitivity of a real-time polymerase chain reaction assay for identification of bovine mastitis pathogens.intramammary infection (imi), also known as mastitis, is the most frequently occurring and economically the most important infectious disease in dairy cattle. this study provides a validation of the analytical specificity and sensitivity of a real-time pcr-based assay that identifies 11 major pathogen species or species groups responsible for imi, and a gene coding for staphylococcal beta-lactamase production (penicillin resistance). altogether, 643 culture isolates originating from clinical bov ...200919233788
structural mimicry of o-antigen by a peptide revealed in a complex with an antibody raised against shigella flexneri serotype 2a.the use of carbohydrate-mimicking peptides to induce immune responses against surface polysaccharides of pathogenic bacteria offers a novel approach to vaccine development. factors governing antigenic and immunogenic mimicry, however, are complex and poorly understood. we have addressed this question using the anti-lipopolysaccharide monoclonal antibody f22-4, which was raised against shigella flexneri serotype 2a and shown to protect against homologous infection in a mouse model. in a previous ...200919328810
antimicrobial susceptibility and mechanisms of resistance in shigella and salmonella isolates from children under five years of age with diarrhea in rural mozambique.the antimicrobial susceptibility and mechanisms of resistance of 109 shigella and 40 salmonella isolates from children with diarrhea in southern mozambique were assessed. the susceptibility to seven antimicrobial agents was tested by disk diffusion, and mechanisms of resistance were searched by pcr or colorimetric method. a high proportion of shigella isolates were resistant to chloramphenicol (chl) (52%), ampicillin (amp) (56%), tetracycline (tet) (66%), and trimethoprim-sulfamethoxazole (sxt) ...200919332670
solar disinfection (sodis) and subsequent dark storage of salmonella typhimurium and shigella flexneri monitored by flow cytometry.pathogenic enteric bacteria are a major cause of drinking water related morbidity and mortality in developing countries. solar disinfection (sodis) is an effective means to fight this problem. in the present study, sodis of two important enteric pathogens, shigella flexneri and salmonella typhimurium, was investigated with a variety of viability indicators including cellular atp levels, efflux pump activity, glucose uptake ability, and polarization and integrity of the cytoplasmic membrane. the ...200919332832
[postinfection irritable bowel syndrome].to characterize pathogenesis, clinicolaboratory criteria and treatment of postinfection irritable bowel syndrome (pics).200919334488
expression, purification, crystallization and preliminary x-ray diffraction analysis of the tonb-dependent haem outer membrane transporter shua from shigella dysenteriae.as part of efforts towards understanding the crystallization of membrane proteins and membrane transport across the outer membrane of gram-negative bacteria, the tonb-dependent haem outer membrane transporter shua of shigella dysenteriae bound to heavy atoms was crystallized in several crystallization conditions using detergents. the insertion of a his(6) tag into an extracellular loop of shua, instead of downstream of the escherichia coli peptide signal, allowed efficient targeting to the outer ...200919342792
global etiology of travelers' diarrhea: systematic review from 1973 to the present.fifty-one published studies of travelers' diarrhea (td) were examined to look for regional differences in pathogens identified. enterotoxigenic e. coli was detected in 1,678/5,518 (30.4%) of td cases overall, with rates in latin america/caribbean (l. america), africa, south asia, and southeast asia of 1,109/3,302 (33.6%), 389/1,217 (31.2%), 153/499 (30.6%), and 36/500 (7.2%), respectively (p < 0.001). enteroaggregative e. coli was the second most common agent in l. america, found in 166/689 (24. ...200919346386
synthesis, characterization, and immunogenicity in mice of shigella sonnei o-specific oligosaccharide-core-protein conjugates.shigellosis, an enteric disease, is on the world health organization's priority prevention list. in one study, the shigella sonnei o-specific polysaccharide (o-sp)-protein conjugate showed 72% protection against disease in israeli army recruits exposed to high rates (8-14%) of infection. the protection was related to vaccine-induced igg anti-o-sp levels. synthetic oligosaccharides of shigella dysenteriae type 1, bound by their reducing ends to a carrier protein ("sun"-type configuration), induce ...200919346477
molecular characterisation of the reca locus in clinical isolates of verocytotoxigenic e. coli o157:h7.molecular epidemiology of verocytoxigenic escherichia coli o157:h7 is important to help elucidate reservoirs and modes of transmission, particularly between animals and humans. as the reca gene locus is now beginning to gain application in bacterial genotyping schemes, and as it has not been examined previously in e. coli o157 isolates, this study aims to examine potential polymorphic variation as a possible epidemiological marker for the subspecies characterisation of clinically significant ver ...200919348125
the pic protease of enteroaggregative escherichia coli promotes intestinal colonization and growth in the presence of mucin.enteroaggregative escherichia coli (eaec) is increasingly being recognized as a cause of diarrheal disease in diverse populations. no small animal model is currently available to study this pathogen. we report here that conventional mice orally inoculated with prototype eaec strain 042 generally became colonized, though the abundance of organisms cultured from their stool varied substantially among individual animals. in contrast, mice whose water contained 5 g/liter streptomycin consistently be ...200919349428
enteric bacterial pathogens in hiv-infected children with acute diarrhea in mulago referral and teaching hospital, kampala, uganda.hiv-infected children develop severe bacterial infections. we set out to determine the enteric bacterial pathogens in hiv-infected children and hiv-negative controls with acute diarrhea and their antimicrobial sensitivities.200919357426
preliminary foodnet data on the incidence of infection with pathogens transmitted commonly through food--10 states, 2008.foodborne diseases remain an important public health problem in the united states. the foodborne diseases active surveillance network (foodnet) of cdc's emerging infections program collects data from 10 u.s. states on diseases caused by enteric pathogens transmitted commonly through food. foodnet is an active, population-based surveillance system for these laboratory-confirmed infections. this report describes preliminary surveillance data for 2008 and trends since 1996. in 2008, the estimated i ...200919357633
virb alleviates h-ns repression of the icsp promoter in shigella flexneri from sites more than one kilobase upstream of the transcription start site.the icsp promoter of shigella spp. is repressed by h-ns and derepressed by virb. here, we show that an inverted repeat located between positions -1144 and -1130 relative to the icsp transcription start site is necessary for virb-dependent derepression. the atypical location of this cis-acting site is discussed.200919363111
potent bactericidal action of a flavonoid fraction isolated from the stem bark of butea frondosa.the flavonoid fraction isolated from the ethyl acetate fraction (bf-1) of butea frondosa (l.) stem bark exhibited distinct antimicrobial activity when tested against 129 bacterial strains belonging to 9 different genera of both gram-positive and gram-negative types. minimum inhibitory concentration (mic) of the fraction bf-1 was determined following nccls guidelines using the agar dilution method. twenty-four out of 36 strains of staphylococcus aureus were inhibited by 50-200 mg/l of the fractio ...200919368121
life on the inside: the intracellular lifestyle of cytosolic bacteria.bacterial pathogens exploit a huge range of niches within their hosts. many pathogens can invade non-phagocytic cells and survive within a membrane-bound compartment. however, only a small number of bacteria, including listeria monocytogenes, shigella flexneri, burkholderia pseudomallei, francisella tularensis and rickettsia spp., can gain access to and proliferate within the host cell cytosol. here, we discuss the mechanisms by which these cytosolic pathogens escape into the cytosol, obtain nut ...200919369949
mechanism of unusual formation of 3-(5-phenyl-3h-[1,2,4]dithiazol-3-yl)chromen-4-ones and 4-oxo-4h-chromene-3-carbothioic acid n-phenylamides and their antimicrobial evaluation.6/6,7-substituted 3-formylchromones (9a-e) react with 2 equivalents of 2-phenyl-4-dimethylamino-1-thia-3-azabuta-1,3-diene (10) or thiobenzamide (11) in refluxing toluene to furnish novel substituted 3-(5-phenyl-3h-[1,2,4]dithiazol-3-yl)chromen-4-ones (12a-e). however, reactions of substituted 2-anilino-3-formylchromones (15a-d) with thiobenzamide (11, 2 equivalents) in refluxing xylene furnish 4-oxo-4h-chromene-3-carbothioic acid n-phenylamide (17a-d) in high yields. a mechanistic rationalizati ...200919375826
intuitionistic fuzzy set vs. fuzzy set application in medical pattern recognition.one of the toughest challenges in medical diagnosis is uncertainty handling. the detection of intestinal bacteria such as salmonella and shigella which cause typhoid fever and dysentery, respectively, is one such challenging problem for microbiologists. they detect the bacteria by the comparison with predefined classes to find the most similar one. consequently, we observe uncertainty in determining the similarity degrees, and therefore, in the bacteria classification. in this paper, we take an ...200919375899
a new ethanolamine phosphate-containing variant of the o-antigen of shigella flexneri type 4a.the o-specific polysaccharide (o-antigen) structure of a shigella flexneri type 4a strain from the dysentery reference laboratory (london, uk) was elucidated in 1978 and its characteristic feature was found to be alpha-d-glucosylation of glcnac at position 6, which defines o-factor iv. our nmr spectroscopic studies of the o-specific polysaccharides of two other strains belonging to s. flexneri type 4a (g1668 from adelaide, australia, and 1359 from moscow, russia) confirmed the carbohydrate backb ...200919376498
[complete structure of the o-polysaccharide from shigella dysenteriae type 10].the structure of the o-specific polysaccharide from shigella dysenteriae type 10, which has been reported previously in bioorg. khim. (1977, vol. 3, pp. 1219-1225), was refined: [formula: see text].200919377533
activating mutations of n-wasp alter shigella pathogenesis.the pathogenesis of shigella requires binding to the host protein n-wasp. to examine the roles of structural conformation and phospho-regulation of n-wasp during shigella pathogenesis, mutant n-wasp constructs predicted to result in a constitutively open conformation (l229p and l232p) or either a phospho-mimicking (y253e) or phospho-disruptive (y253f) structure were constructed. pyrene actin assays demonstrated that the n-wasp l229p and l232p constructs are constitutively active. despite the inc ...200919379711
unc119 protects from shigella infection by inhibiting the abl family kinases.bacteria engage cell surface receptors and intracellular signaling molecules to enter the cell. unc119 is an adaptor protein, which interacts with receptors and tyrosine kinases. its role in bacterial invasion of cells is unknown.200919381274
role of azithromycin against clinical isolates of family enterobacteriaceae: a comparison of its minimum inhibitory concentration by three different methods.to determine the effect of azithromycin, a new azalide antibiotic, on clinical isolates of the family enterobacteriaceae and to determine and compare its minimum inhibitory concentration (mic) by disk diffusion, agar dilution and e-test methods.200919384031
altered expression of inflammatory cytokine receptors in response to lps challenge through interaction between intestinal epithelial cells and lymphocytes of peyer's patch.the intense innate immunological activities occurring at the enteric mucosal surface involve interactions between intestinal epithelial cells and immune cells. our previous studies have indicated that peyer's patch lymphocytes may modulate intestinal epithelial barrier and ion transport function in homeostasis and host defense via cell-cell contact as well as cytokine signaling. the present study was undertaken using the established co-culture system of caco-2 epithelial cells with lymphocytes o ...200919385035
inactivation of salmonella enteritidis in chicken breast fillets by single-cycle and multiple-cycle high pressure treatments.the effect of single-cycle and multiple-cycle high hydrostatic pressure (hhp) treatments on the survival of three salmonella enteritidis strains in chicken breast fillets was investigated. the surface of fillets was inoculated with a cocktail of three salmonella strains at approximately 10(7) colony-forming units (cfu)/g, and held at 4 degrees c for 20 hours before hhp treatments. reduction of salmonella counts on tryptic soy agar (tsa) by single-cycle treatments at 300 mpa and 12 degrees c rang ...200919388832
three-dimensional reconstruction of the shigella t3ss transmembrane regions reveals 12-fold symmetry and novel features throughout.type iii secretion systems (t3sss) mediate bacterial protein translocation into eukaryotic cells, a process essential for virulence of many gram-negative pathogens. they are composed of a cytoplasmic secretion machinery and a base that bridges both bacterial membranes, into which a hollow, external needle is embedded. when isolated, the latter two parts are termed the 'needle complex'. an incomplete understanding of the structure of the needle complex has hampered studies of t3ss function. to es ...200919396171
ectopic production of vapcs from enterobacteria inhibits translation and trans-activates yoeb mrna interferase.toxin-antitoxin loci have been identified in almost all free-living prokaryotes, often in high copy numbers. the biological function and molecular targets of the abundant vapbc loci are not yet known. here we analyse the vapbc loci of salmonella lt2 and shigella plasmid pmysh6000. both loci encode putative pin (pilt n-terminal) domain toxins, and antitoxins that may regulate vapbc transcription. we show that vapbc(lt2) and vapbc(pmysh) are bona fide ta loci: (i) both vapcs inhibited cell growth ...200919400780
antimicrobial activity of endemic digitalis lamarckii ivan from turkey.antimicrobial activity of the methanolic extracts of leaves and flowers of d. lamarckii ivan, (scophulariaceae), an endemic plant species of turkey, was tested on ten bacterial and four yeast strains. effective antibacterial activity was observed in four bacterial strains. minimum inhibitory concentration (mic) was calculated by use of liquid culture tests and in all the four effective bacterial strains, the mic was found to be > or = 199.5 mg/ml. the minimum bactericidal concentration (mbc) of ...200919405389
estimated burden of human salmonella, shigella, and brucella infections in jordan, 2003-2004.there is limited information on the disease burden due to foodborne pathogens in the eastern mediterranean region. this study estimates the burden of disease in jordan for salmonella, shigella, and brucella during 1 year.200919415972
rapidly fatal bacteremia caused by shigella sonnei without preceding gastrointestinal symptoms in an adult patient with lung cancer. 200919416029
synthesis, spectral characterization, in-vitro microbiological evaluation and cytotoxic activities of novel macrocyclic bis hydrazone.a macrocyclic hydrazone schiff base was synthesized by reacting 1,4-dicarbonyl phenyl dihydrazide with 2,6-diformyl-4-methyl phenol and a series of metal complexes with this new schiff base were synthesized by reaction with co(ii), ni(ii) and cu(ii) metal salts. the schiff base and its complexes have been characterized by elemental analyses, ir, (1)h nmr, uv-vis, fab mass, esr spectra, fluorescence, thermal, magnetic and molar conductance data. the analytical data reveal that the co(ii), ni(ii) ...200919419802
going round in circles: the structural biology of type iii secretion systems. 200919421157
determination of emitted airborne microorganisms from a bio-pak wastewater treatment plant.results of a study conducted to assess the degree of airborne microbial contamination generated by a wastewater treatment plant (wwtp) with bioreactor "bio-pak" closed treatment system and evaluation of the dispersion of potential pathogens are described. over the year aerosol samples were collected simultaneously with sedimentation and impact methods from several plant sites and the surroundings. external upwind sites were used as control. total colony-forming counts of heterotrophic psychrophi ...200919428042
design of alpha-transglucosidases of controlled specificity for programmed chemoenzymatic synthesis of antigenic oligosaccharides.combined with chemical synthesis, the use of biocatalysts holds great potential to open the way to novel molecular diversity. we report in vitro chemoenzymatic pathways that, for the first time, take advantage of enzyme engineering to produce complex microbial cell-surface oligosaccharides and circumvent the chemical boundaries of glycochemistry. glycoenzymes were designed to act on nonnatural conveniently protected substrates to produce intermediates compatible with a programmed chemical elonga ...200919432472
liposomes recruit ipac to the shigella flexneri type iii secretion apparatus needle as a final step in secretion induction.shigella flexneri contact with enterocytes induces a burst of protein secretion via its type iii secretion apparatus (ttsa) as an initial step in cellular invasion. we have previously reported that ipad is positioned at the ttsa needle tip (m. espina et al., infect. immuno. 74:4391-4400, 2006). from this position, ipad senses small molecules in the environment to control the presentation of ipab to the needle tip. this step occurs without type iii secretion induction or ipac recruitment to the s ...200919433542
the rho gtpase inactivation domain in vibrio cholerae martx toxin has a circularly permuted papain-like thiol protease fold.a rho gtpase inactivation domain (rid) has been discovered in the multifunctional, autoprocessing rtx toxin rtxa from vibrio cholerae. the rid domain causes actin depolymerization and rounding of host cells through inactivation of the small rho gtpases rho, rac, and cdc42. with only a few toxin proteins containing rid domains in the current sequence database, the structure and molecular mechanisms of this domain are unknown. using comparative sequence and structural analyses, we report homology ...200919434753
go4genome: a prokaryotic phylogeny based on genome organization.determining the phylogeny of closely related prokaryotes may fail in an analysis of rrna or a small set of sequences. whole-genome phylogeny utilizes the maximally available sample space. for a precise determination of genome similarity, two aspects have to be considered when developing an algorithm of whole-genome phylogeny: (1) gene order conservation is a more precise signal than gene content; and (2) when using sequence similarity, failures in identifying orthologues or the in situ replaceme ...200919436929
determination of foodborne pathogenic bacteria by multiplex pcr-microchip capillary electrophoresis with genetic algorithm-support vector regression optimization.a rapid and sensitive method based on microchip capillary electrophoresis with condition optimization of genetic algorithm-support vector regression (ga-svr) was developed and applied to simultaneous analysis of multiplex pcr products of four foodborne pathogenic bacteria. four pairs of oligonucleotide primers were designed to exclusively amplify the targeted gene of vibrio parahemolyticus, salmonella, escherichia coli (e. coli) o157:h7, shigella and the quadruplex pcr parameters were optimized. ...200919446070
rapid emergence of third generation cephalosporin resistant shigella spp. in southern vietnam. 200919141753
giardia duodenalis assemblages associated with diarrhea in children in south india identified by pcr-rflp.giardial diarrhea in a birth cohort of 452 children in an urban slum in south india was characterized. of the 155 episodes that occurred in 99 children, 73% were acute diarrhea. children with better educated mothers and a toilet at home had lower odds of acquiring giardial diarrhea, whereas low socioeconomic status and drinking municipal water were associated with greater risk. children with co-infections tended to have a slightly longer duration of diarrhea (p = 0.061) and showed significantly ...200919141832
improvement in detection of enterotoxigenic escherichia coli in patients with travelers' diarrhea by increasing the number of e. coli colonies tested.no cause of one-third of travelers' diarrhea (td) cases can be detected despite microbiologic assessment. we propose that these pathogen-negative td cases include undetected enterotoxigenic escherichia coli (etec). as a standard in diagnostic microbiology, samples of five e. coli colonies were tested to detect etec from stool cultures. we compared the sensitivities and the number of etec detected by 20 colonies with those of 5, 10, and 15 colonies. the percent detection of etec with five e. coli ...200919141833
septins regulate bacterial entry into host cells.septins are conserved gtpases that form filaments and are required in many organisms for several processes including cytokinesis. we previously identified sept9 associated with phagosomes containing latex beads coated with the listeria surface protein inlb.200919145258
etiology of acute gastroenteritis in three sentinel general practices, austria 2007.we studied the etiology of acute gastroenteritis in a village with a total population of approximately 6,000. this is the first study in austria that has investigated a broad range of pathogens recovered from an unselected population of patients who had consulted general practitioners because of gastroenteritis.200919148576
molecular detection of all 34 distinct o-antigen forms of shigella.shigella is the cause of shigellosis or bacillary dysentery, the occurrence of which is estimated to be 165 million cases per year worldwide, resulting in 1.1 million deaths. rapid and reliable assays for detecting and identifying shigella in food, environmental and clinical samples are therefore necessary. shigella species are traditionally identified by their o antigens. this study developed a dna microarray targeting o-serotype-specific genes to detect all 34 distinct o-antigen forms of shige ...200919074655
a similarity in the o-acetylation pattern of the o-antigens of shigellaflexneri types 1a, 1b, and 2a.shigella flexneri type 2a is the first, and type 1b is the second, most prevalent isolates from patients with shigellosis in russia. the o-specific polysaccharides (opss, o-antigens) of s. flexneri types 1-5 possess a common -->2)-alpha-l-rhapiii-(1-->2)-alpha-l-rhapii-(1-->3)-alpha-l-rhapi-(1-->3)-beta-d-glcpnac-(1--> backbone and differ from each other in its glucosylation or/and o-acetylation at various positions, the modifications being responsible for various o-factors. it was suggested tha ...200919246033
the clinical course of postinfectious irritable bowel syndrome: a five-year follow-up study.irritable bowel syndrome (ibs) is a common disorder seen in general practice. bacterial gastroenteritis has been known to be a risk factor for ibs. we investigated the clinical course, risk factors, and prognosis of postinfectious ibs (pi-ibs) 5 years after shigella infection.200919262407
the mere protein encoded by transposon tn21 is a broad mercury transporter in escherichia coli.in order to clarify the physiological role of the mere gene of transposon tn21, a pe4 plasmid that contained the merr gene of plasmid pmr26 from pseudomonas strain k-62, and the mere gene of tn21 from the shigella flexneri plasmid nr1 (r100) was constructed. bacteria with plasmid pe4 (merr-o/p-mere) were more hypersensitive to ch(3)hg(i) and hg(ii), and took up significantly more ch(3)hg(i) and hg(ii), than the isogenic strain. the mere protein encoded by pe4 was localized in the membrane cell f ...200919265693
piscidin 4, a novel member of the piscidin family of antimicrobial peptides.piscidins are linear, amphipathic, antimicrobial peptides (amps) with broad, potent, activity spectrum. piscidins and other members of the piscidin family appear to comprise the most common group of amps in teleost fish. all piscidins and related members of the piscidin family described to date are 18-26 amino acids long.we report here the isolation of a novel 5329.25 da, 44-residue (ffrhlfrgakaifrgarqgxrahkvvsryrnrdvpetdnnqeep) antimicrobial peptide from hybrid striped bass (morone chrysops fem ...200919266617
high-let ion radiolysis of water: oxygen production in tracks.it is known that molecular oxygen is a product of the radiolysis of water with high-linear energy transfer (let) radiation, a result that is of particular significance in radiobiology and of practical relevance in radiotherapy. in fact, it has been suggested that the radiolytic formation of an oxygenated microenvironment around the tracks of high-let heavy ions is an important factor in their enhanced biological efficiency in the sense that this may be due to an "oxygen effect" by o(2) produced ...200919267566
the effects of the bacterial interaction with visible-light responsive titania photocatalyst on the bactericidal performance.bactericidal activity of traditional titanium dioxide (tio2) photocatalyst is effective only upon irradiation by ultraviolet light, which restricts the potential applications of tio2 for use in our living environments. recently carbon-containing tio2 was found to be photoactive at visible-light illumination that affords the potential to overcome this problem; although, the bactericidal activity of these photocatalysts is relatively lower than conventional disinfectants. evidenced from scanning e ...200919272171
characterisation of early mucosal and neuronal lesions following shigella flexneri infection in human colon.shigella, an enteroinvasive bacteria induces a major inflammatory response responsible for acute rectocolitis in humans. however, early effect of shigella flexneri (s. flexneri) infection upon the human mucosa and its microenvironement, in particular the enteric nervous system, remains currently unknown. therefore, in this study, we sought to characterize ex vivo the early events of shigellosis in a model of human colonic explants. in particular, we aimed at identifying factors produced by s. fl ...200919274103
efficient synthesis of six tri- to hexasaccharide fragments of shigella flexneri serotypes 3a and/or x o-antigen, including a study on acceptors containing n-trichloroacetylglucosamine versus n-acetylglucosamine.six tri- to hexasaccharide fragments of the {2)-[alpha-d-glcp-(1-->3)]-alpha-l-rhap-(1-->2)-alpha-l-rhap-(1-->3)-[ac-->2]-alpha-l-rhap-(1-->3)-beta-d-glcpnac-(1-->}(n) polymer ([(e)ab(ac)cd](n)) were synthesized as their propyl glycosides. all targets share the (e)ab sequence. following a thorough investigation on the use of n-trichloroacetylglucosamine- versus n-acetylglucosamine-containing tri- and tetrasaccharide acceptors, the successful strategy was based on an efficient combination of the ...200919278208
foodborne outbreaks, austria 2007.in 2007 austria reported a total of 438 foodborne outbreaks affecting 1715 people, including 286 hospitalized patients and one death. salmonella spp. and campylobacter spp. accounted for 95% of all reported outbreaks. forty-eight (11%) of the 438 austrian outbreaks were acquired abroad. of the 390 domestically acquired foodborne outbreaks, bacterial infection caused 376, viruses (norovirus and 1-time hepatitis a virus) caused 11, and intoxications (staphylococcus aureus enterotoxins, alkaloid to ...200919280130
a food-borne outbreak of shigella sonnei gastroenteritis, austria, 2008.we report on the first foodborne outbreak of shigella sonnei described in austria. on july 14 2008, ages was informed of a cluster of 22 laboratory-confirmed cases of infection with s. sonnei restricted to public health district x in the province of salzburg. all cases had attended a youth-group trip to a small village in the province of tyrol from july 7 to july 9. an outbreak case among the trip participants was a person who (1) attended the trip and (2) fell ill with diarrhea in the period be ...200919280143
tri-county comprehensive assessment of risk factors for sporadic reportable bacterial enteric infection in children.the aim of this study was to determine risk factors for childhood sporadic reportable enteric infection (rei) caused by bacteria, specifically campylobacter, salmonella, escherichia coli o157, or shigella (rei-b).200919281302
application of a multiplex pcr assay for the detection of shigella, escherichia coli and shiga toxin-producing esch. coli in milk.a multiplex pcr (mpcr) assay using previously known genetic markers of shigella, escherichia coli and shiga-toxic esch. coli was standardized. uida gene was targeted for the common detection of esch. coli and shigella, whereas ipah and stx1 genes were used as markers for the detection of shigella and shiga-toxin producing strains, respectively. the standardized assays detected the target organism specifically and selectively. the mpcr developed by combining all the three reactions generated spec ...200919281632
antimicrobial activity of the methanolic extract and compounds from morus mesozygia stem bark.this study was aimed at investigating the antimicrobial activity of the methanolic extract (mmb) and compounds isolated from the stem bark of morus mesozygia, namely 3beta-acetoxyurs-12-en-11-one (1), moracin q (2), moracin t (3), artocarpesin (4), cycloartocarpesin (5), moracin r (6), moracin u (8), moracin c (9), and moracin m (10).200919450674
diagnosis and treatment of acute or persistent diarrhea.studies of microbial pathogens and the toxins they produce are important for determining the mechanisms by which they cause disease and spread throughout a population. some bacteria produce secretory enterotoxins (such as cholera toxin or the heat-labile or stable enterotoxins produced by escherichia coli) that invade cells directly. others invade cells or produce cytotoxins (such as those produced by shigella, enteroinvasive e coli, or clostridium difficile) that damage cells or trigger host re ...200919457416
molecular typing methodologies for microbial source tracking and epidemiological investigations of gram-negative bacterial foodborne pathogens.gram-negative bacterial foodborne pathogens are a worldwide cause of morbidity and mortality. the ability to carry out epidemiological investigations to determine the primary sources of bacterial contamination is important to improve public health. multiple methods are available for bacterial source tracking and to determine the distribution of pathogens isolated from sick patients. the molecular based typing methods available fall into three general categories: those based on restriction analys ...200919460308
metabolic control through ornithine and uracil of epithelial cell invasion by shigella flexneri.this paper shows that compounds in defined growth media strongly influence the expression of the effectors of virulence in the human invasive pathogen shigella flexneri. ornithine in conjunction with uracil reduces the haemolytic ability of wild-type cultures more than 20-fold and the expression of the type iii secretion system more than 8-fold, as monitored by an mxic : : lacz transcriptional reporter. mxic gene expression is further decreased by the presence of methionine or branched-chain ami ...200919460819
design, synthesis, and immunochemical characterization of a chimeric glycopeptide corresponding to the shigella flexneri y o-polysaccharide and its peptide mimic mdwnmhaa.two glycopeptide chimeras corresponding to the shigella flexneri y o-polysaccharide and its peptide mimic were designed in an attempt to improve the binding affinity by increasing the entropy of binding relative to the original octapeptide mimic of the o-polysaccharide. the design was based on the x-ray crystal structures of a monoclonal antibody sya/j6 in complex with its cognate ligands, a pentasaccharide corresponding to the s. flexneri y o-polysaccharide and the octapeptide mimic, mdwnmhaa. ...200919467535
rapid detection of intestinal pathogens in fecal samples by an improved reverse dot blot method.to develop a new, rapid and accurate reverse dot blot (rdb) method for the detection of intestinal pathogens in fecal samples.200919469006
incidence of multiple antibiotic resistant gram-negative bacteria isolated from surface and underground water sources in south western region of nigeria.in most rural and urban settlements, particularly in nigeria, wells, spring, streams or rivers and lakes serves as major sources of water supply for drinking and other domestic purposes. unfortunately, many of the available water sources are not potable without some form of treatment which is seldom available in most settings. the use of untreated surface water sources for drinking and for domestic purposes remains a major threat to public health as these could serve as reservoirs the for transf ...200919474486
involvement of rna-binding protein hfq in the osmotic-response regulation of inve gene expression in shigella sonnei.the expression of type iii secretion system (ttss) in shigella is regulated in response to changes in environmental osmolarity and temperature. temperature-dependent regulation of virf, the master regulator of ttss synthesis, is believed to occur at the transcriptional level. we recently demonstrated, however, that ttss synthesis also involves post-transcriptional regulation of the synthesis of inve, a target of virf and key regulator of ttss synthesis. the mrna levels of inve (virb) are stable ...200919476612
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