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nlrp10 enhances shigella-induced pro-inflammatory responses.members of the nlr family evolved as intracellular sensors for bacterial and viral infection. however, our knowledge on the implication of most of the human nlr proteins in innate immune responses still remains fragmentary. here we characterized the role of human nlrp10 in bacterial infection. our data revealed that nlrp10 is a cytoplasmic localized protein that positively contributes to innate immune responses induced by the invasive bacterial pathogen shigella flexneri. sirna-mediated knock-do ...201222672233
two live attenuated shigella flexneri 2a strains wrsf2g12 and wrsf2g15: a new combination of gene deletions for 2nd generation live attenuated vaccine candidates.shigella infections are a major cause of inflammatory diarrhea and dysentery worldwide. first-generation virg-based live attenuated shigella strains have been successfully tested in phase i and ii clinical trials and are a leading approach for shigella vaccine development. additional gene deletions in sena, senb and msbb2 have been engineered into second-generation virg-based shigella flexneri 2a strains producing wrsf2g12 and wrsf2g15. both strains harbor a unique combination of gene deletions ...201222658966
roles of h2 uptake hydrogenases in shigella flexneri acid tolerance.hydrogenases play many roles in bacterial physiology, and use of h(2) by the uptake-type enzymes of animal pathogens is of particular interest. hydrogenases have never been studied in the pathogen shigella, so targeted mutant strains were individually generated in the two shigella flexneri h(2)-uptake enzymes (hya and hyb) and in the h(2)-evolving enzyme (hyc) to address their roles. under anaerobic fermentative conditions, a hya mutant strain (hya) was unable to oxidize h(2), while a hyb mutant ...201222628482
synthesis of s-triazine-based thiazolidinones as antimicrobial agents.a novel series of thiazolidinone derivatives, namely 4-{4-dimethylamino-6-[4-oxo-2-phenyl-5-(4-pyridin-2-yl-piperazin-1-ylmethyl)-thiazolidin-3-yl]-[1,3,5]-triazin-2-yloxy}-1-methyl-1h-quinolin-2-ones, have been synthesized from the key intermediate 4-(4-amino-6-dimethylamino-[1,3,5]-triazin-2-yloxy)-1-methyl-1h-quinolin-2-one (5). compound 5 was condensed with various aldehydes to give schiff base derivatives, which after cyclization gave thiazolidinones that were linked with 1-pyridin-2-yl-pip ...201222624326
functional analysis of nopm, a novel e3 ubiquitin ligase (nel) domain effector of rhizobium sp. strain ngr234.type 3 effector proteins secreted via the bacterial type 3 secretion system (t3ss) are not only virulence factors of pathogenic bacteria, but also influence symbiotic interactions between nitrogen-fixing nodule bacteria (rhizobia) and leguminous host plants. in this study, we characterized nopm (nodulation outer protein m) of rhizobium sp. strain ngr234, which shows sequence similarities with novel e3 ubiquitin ligase (nel) domain effectors from the human pathogens shigella flexneri and salomone ...201222615567
[development of a singleplex pcr assay targeting o-antigen modification genes for molecular serotyping of shigella flexneri].to develop a singleplex pcr assay targeting o-antigen modification genes for molecular serotyping of shigella (s.) flexneri.201222613389
antimicrobial effects of psidium guajava extract as one mechanism of its antidiarrhoeal action.a morphine-like spasmolytic action (not naloxone reversible; involving the inhibition of acetylcholine release) and also effects on the transmural transport of electrolytes (na(+) and k(+)) and water have been reported as possible modes of the antidiarrhoeal action of polar fractions of psidium guajava leaf extractives. the objective for this study was to verify if the reported modes of the antidiarrhoeal action should be broadened to include direct antimicrobial actions on some of the more comm ...199922589684
investigations of antimicrobial activity of some cameroonian medicinal plant extracts against bacteria and yeast with gastrointestinal relevance.resistance against antibiotics of many bacteria is accumulating. therefore, searches for new substances with antimicrobial activity have become an urgent necessity. medicinal plants are frequently used in popular medicine as remedies for many infectious diseases (intestinal infection, malaria, tuberculosis, etc.).201222583961
antimicrobial activity of sesbania grandiflora flower polyphenol extracts on some pathogenic bacteria and growth stimulatory effect on the probiotic organism lactobacillus acidophilus.polyphenolic extracts (pe) of edible flower of sesbania grandiflora were tested to evaluate its antimicrobial effect against some common pathogenic bacteria and growth promoting property against probiotic organism lactobacillus acidophilus. the antimicrobial activity of s. grandiflora flower pe against selected pathogens was evaluated using both in vitro and in situ methods. in vitro studies suggested that pe has inhibitory effect against staphylococcus aureus, shigella flexneri 2a, salmonella t ...201222583547
genome sequence of shigella flexneri serotype 5a strain m90t sm.bacteria of the genus shigella are a major cause of death worldwide (l. von seidlein et al., plos med. 3:e353, 2006). we sequenced the genome of shigella flexneri strain m90t sm (serotype 5a) and compared it to the published genome sequence of s. flexneri strain 8401 (serotype 5b).201222582379
antimicrobial susceptibility patterns of shigella isolates in foodborne diseases active surveillance network (foodnet) sites, 2000-2010.treatment of shigellosis with appropriate antimicrobial agents shortens duration of illness and bacterial shedding, but resistance to commonly used agents is increasing.201222572670
shigella flexneri effectors ospe1 and ospe2 mediate induced adherence to the colonic epithelium following bile salts exposure.shigella flexneri is a gram-negative pathogen that invades the colonic epithelium. while invasion has been thoroughly investigated, it is unknown how shigella first attaches to the epithelium. previous literature suggests that shigella utilizes adhesins that are induced by environmental signals, including bile salts, encountered in the small intestine prior to invasion. we hypothesized that bile would induce adherence factors to facilitate attachment to colonic epithelial cells. to test our hypo ...201222571618
intestinal microbial community diversity between healthy and orally infected rabbit with entamoeba histolytica by eric-pcr.enterobacterial repetitive intergenic consensus (eric)-pcr was applied to analyze the difference of intestinal microbial community diversity between healthy and orally infected rabbits with entamoeba histolytica. the dynamic changes in different parts of digestive system including the duodenum, jejunum, ileum, caecum, and rectum in healthy and infected rabbits at different time points were also tested. the intestinal microbial community of the control healthy rabbits was steady, and the total nu ...201222562215
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
antibacterial acivity of the essential oil of lippie nodiflora.the plant lippia nodiflora (family-verbenaceae) has medicinal properties and particularly used as an antidandruff agent. the essential oil of the plant was tested for its antibacterial activity against both gram positive and gram negative bacteria. it showed good activity and compared with standard neomycin sulphate. however, it was inactive in the case of shigella flexneri.199622556775
prevalence of plasmid-mediated quinolone resistance determinants in association with β-lactamases, 16s rrna methylase genes and integrons amongst clinical isolates of shigella flexneri. 201222556328
complete nucleotide sequence of pvqs1 containing a quinolone resistance determinant from salmonella enterica serovar virchow associated with foreign travel.nalidixic acid-resistant salmonella enterica serovars kentucky (n = 5) and virchow (n = 6) cultured from individuals were investigated for the presence of plasmid-mediated quinolone resistance (pmqr) determinants.201222553140
nlrc4 inflammasome-mediated production of il-1β modulates mucosal immunity in the lung against gram-negative bacterial infection.bacterial flagellin is critical to mediate nlrc4 inflammasome-dependent caspase-1 activation. however, shigella flexneri, a nonflagellated bacterium, and a flagellin (flic) knockout strain of pseudomonas aeruginosa are known to activate nlrc4 in bone marrow-derived macrophages. furthermore, the flagellin-deficient flic strain of p. aeruginosa was used in a mouse model of peritonitis to show the requirement of nlrc4. in a model of pulmonary p. aeruginosa infection, flagellin was shown to be essen ...201222547706
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
molecular cloning and characterization of nucleotide binding and oligomerization domain-1 (nod1) receptor in the indian major carp, rohu (labeo rohita), and analysis of its inductive expression and down-stream signalling molecules following ligands exposure and gram-negative bacterial infections.nucleotide binding and oligomerization domain-1 (nod1) is a cytoplasmic pattern recognition receptor (prr), and is a member of the nod-like receptor (nlr) family. it senses a wide range of bacteria and viruses or their products, and plays a key role in inducing innate immunity. in this report, nod1 gene was cloned and characterized in rohu (labeo rohita), a fish species of highest commercial importance in the indian subcontinent. the full-length rohu nod1 (rnod1) cdna comprised of 3168 bp with a ...201222530240
molecular-phylogenetic characterization of the microbiota in ulcerated and non-ulcerated regions in the patients with crohn's disease.the dysbiosis of intestinal microbiota has been established in crohn's disease (cd), but the molecular characterization of this dysbiosis in chinese subjects with cd remains unclear. this study aims to investigate the predominant bacterial composition of the faecal and mucosal-associated microbiota in chinese cd patients using culture-independent techniques.201222529960
hierarchies of host factor dynamics at the entry site of shigella flexneri during host cell invasion.shigella flexneri, the causative agent of bacillary dysentery, induces massive cytoskeletal rearrangement, resulting in its entry into nonphagocytic epithelial cells. the bacterium-engulfing membrane ruffles are formed by polymerizing actin, a process activated through injected bacterial effectors that target host small gtpases and tyrosine kinases. once inside the host cell, s. flexneri escapes from the endocytic vacuole within minutes to move intra- and intercellularly. we quantified the fluor ...201222526677
storing drinking-water in copper pots kills contaminating diarrhoeagenic bacteria.microbially-unsafe water is still a major concern in most developing countries. although many water-purification methods exist, these are expensive and beyond the reach of many people, especially in rural areas. ayurveda recommends the use of copper for storing drinking-water. therefore, the objective of this study was to evaluate the effect of copper pot on microbially-contaminated drinking-water. the antibacterial effect of copper pot against important diarrhoeagenic bacteria, including vibrio ...201222524115
temperature depended role of shigella flexneri invasion plasmid on the interaction with acanthamoeba castellanii.shigella flexneri is a gram-negative bacterium causing the diarrhoeal disease shigellosis in humans. the virulence genes required for invasion are clustered on a large 220 kb plasmid encoding type three secretion system (ttss) apparatus and virulence factors such as adhesions and invasion plasmid antigens (ipa). the bacterium is transmitted by contaminated food, water, or from person to person. acanthamoebae are free-living amoebae (fla) which are found in diverse environments and isolated from ...201222518151
synthesis of benzimidazolyl-1,3,4-oxadiazol-2ylthio-n-phenyl (benzothiazolyl) acetamides as antibacterial, antifungal and antituberculosis agents.to affiliate multiple bioactivities in a compact heteronuclei, two series of benzimidazole based 1,3,4-oxadiazoles were synthesized and assessed in vitro for their efficacy as antimicrobial agents against eight bacteria (staphylococcus aureus, bacillus cereus, escherichia coli, pseudomonas aeruginosa, klebsiella pneumoniae, salmonella typhi, proteus vulgaris, shigella flexneri), four fungi (aspergillus niger, aspergillus fumigatus, aspergillus clavatus, candida albicans) and mycobacterium tuberc ...201222516426
self-association of the shigella flexneri icsa autotransporter protein.the icsa autotransporter protein is a major virulence factor of the human intracellular pathogen shigella flexneri. icsa is distributed at the poles in the outer membrane (om) of s. flexneri and interacts with components of the host actin-polymerization machinery to facilitate intracellular actin-based motility and subsequent cell-to-cell spreading of the bacterium. we sought to characterize the biochemical properties of icsa in the bacterial om. chemical cross-linking data suggested that icsa e ...201222516224
standardization and international multicenter validation of a pulsenet pulsed-field gel electrophoresis protocol for subtyping shigella flexneri isolates.shigella flexneri is one of the agents most frequently linked to diarrheal illness in developing countries and often causes outbreaks in settings with poor hygiene or sanitary conditions. travel is one of the means by which s. flexneri can be imported into developed countries, where this pathogen is not commonly seen. a robust and discriminatory subtyping method is needed for the surveillance of s. flexneri locally and regionally, and to aid in the detection and investigation of outbreaks. the p ...201222506731
epidemiological study of shigellosis in an urban area of argentina.shigellosis represents one of the main causes of bloody diarrhoea in south america. this study aimed to establish the incidence of shigellosis in an urban zone of buenos aires, argentina, by examining the type of shigella and living conditions associated with this infection.201222505441
binding affects the tertiary and quaternary structures of the shigella translocator protein ipab and its chaperone ipgc.shigella flexneri uses its type iii secretion system (t3ss) to promote invasion of human intestinal epithelial cells as the first step in causing shigellosis, a life-threatening form of dysentery. the shigella type iii secretion apparatus (t3sa) consists of a basal body that spans the bacterial envelope and an exposed needle that injects effector proteins into target cells. the nascent shigella t3sa needle is topped with a pentamer of the needle tip protein invasion plasmid antigen d (ipad). bil ...201222497344
ongoing outbreak of shigella flexneri serotype 3a in men who have sex with men in england and wales, data from 2009-2011.diagnoses of shigella flexneri in the united kingdom (uk) are usually travel-related. however, since 2009, there has been an overall increase in uk-acquired cases. the health protection agency has been investigating a national outbreak of s. flexneri detected in 2011 and which is still ongoing. cases occurred mostly in men who have sex with men and were of serotype 3a. the investigation aimed at obtaining epidemiological data to inform targeted outbreak management and control.201222490381
comparison of the prevalence and changing resistance to nalidixic acid and ciprofloxacin of shigella between europe-america and asia-africa from 1998 to 2009.shigella is becoming an increasing public health problem due to development of multiple antimicrobial resistance, frequently resulting in treatment failure. a systematic review was conducted based on a literature search of computerised databases. random or fixed-effects models were used, based on the p-value considering the possibility of heterogeneity between studies, for meta-analysis. statistical analyses were performed using stata 10.0. in the area of asia-africa, resistance rates to nalidix ...201222483324
ultrastructural analysis of ipad at the tip of the nascent mxih type iii secretion apparatus of shigella flexneri.shigella flexneri is a gram-negative enteric pathogen that is the predominant cause of bacillary dysentery. shigella uses a type iii secretion system to deliver effector proteins that alter normal target cell functions to promote pathogen invasion. the type iii secretion apparatus (t3sa) consists of a basal body, an extracellular needle, and a tip complex that is responsible for delivering effectors into the host cell cytoplasm. ipad [ipa (invasion plasmid antigen)] is the first protein to local ...201222480614
systemic shigellosis in south africa.systemic disease due to shigellae is associated with human immunodeficiency virus (hiv), malnutrition, and other immunosuppressed states. we examined the clinical and microbiologic characteristics of systemic shigellosis in south africa, where rates of hiv infection are high.201222474223
[antagonistic activity of lactobacilli of the colon].study of antagonistic activity of lactobacilli of the colon against members of its autochthonous bacterial flora and agents of some acute infectious and chronic diseases of the gastrointestinal tract.201222442970
structural characterization of closely related o-antigen lipopolysaccharide (lps) chain length regulators.the surface o-antigen polymers of gram-negative bacteria exhibit a modal length distribution that depends on dedicated chain length regulator periplasmic proteins (polysaccharide co-polymerases, pcps) anchored in the inner membrane by two transmembrane helices. in an attempt to determine whether structural changes underlie the o-antigen modal length specification, we have determined the crystal structures of several closely related pcps, namely two chimeric pcp-1 family members solved at 1.6 and ...201222437828
common changes in global gene expression induced by rna polymerase inhibitors in shigella flexneri.characterization of expression profile of organisms in response to antimicrobials provides important information on the potential mechanism of action of the drugs. the special expression signature can be used to predict whether other drugs act on the same target. here, the common response of shigella flexneri to two inhibitors of rna polymerase was examined using gene expression profiling. consistent with similar effects of the two drugs, the gene expression profiles indicated that responses of ...201222428000
characterization of the promoter, mxie box and 5' utr of genes controlled by the activity of the type iii secretion apparatus in shigella flexneri.activation of the type iii secretion apparatus (t3sa) of shigella flexneri, upon contact of the bacteria with host cells, and its deregulation, as in ipab mutants, specifically increases transcription of a set of effector-encoding genes controlled by mxie, an activator of the arac family, and ipgc, the chaperone of the ipab and ipac translocators. thirteen genes carried by the virulence plasmid (ospb, ospc1, ospd2, ospd3, ospe1, ospe2, ospf, ospg, vira, ipah1.4, ipah4.5, ipah7.8 and ipah9.8) and ...201222427898
shigella flexneri utilize the spectrin cytoskeleton during invasion and comet tail generation.the spectrin cytoskeleton is emerging as an important host cell target of enteric bacterial pathogens. recent studies have identified a crucial role for spectrin and its associated proteins during key pathogenic processes of listeria monocytogenes and salmonella typhimurium infections. here we investigate the involvement of spectrin cytoskeletal components during the pathogenesis of the invasive pathogen shigella flexneri.201222424399
calpain activation by the shigella flexneri effector vira regulates key steps in the formation and life of the bacterium's epithelial niche.the enteropathogen shigella flexneri invades epithelial cells, leading to inflammation and tissue destruction. we report that shigella infection of epithelial cells induces an early genotoxic stress, but the resulting p53 response and cell death are impaired due to the bacterium's ability to promote p53 degradation, mainly through calpain protease activation. calpain activation is promoted by the shigella virulence effector vira and dependent on calcium flux and the depletion of the endogenous c ...201222423964
identification of the bile salt binding site on ipad from shigella flexneri and the influence of ligand binding on ipad structure.type iii secretion (tts) is an essential virulence factor for shigella flexneri, the causative agent of shigellosis. the shigella tts apparatus (ttsa) is an elegant nanomachine that is composed of a basal body, an external needle to deliver effectors into human cells, and a needle tip complex that controls secretion activation. ipad is at the tip of the nascent ttsa needle where it controls the first step of tts activation. the bile salt deoxycholate (doc) binds to ipad to induce recruitment of ...201222423359
cephalosporin-resistant shigella flexneri over 9 years (2001-09) in india.to determine the pattern and antimicrobial resistance genes of cephalosporin resistance in shigella flexneri and shigella dysenteriae over 9 years.201222410619
the shigella flexneri effector ospi deamidates ubc13 to dampen the inflammatory response.many bacterial pathogens can enter various host cells and then survive intracellularly, transiently evade humoral immunity, and further disseminate to other cells and tissues. when bacteria enter host cells and replicate intracellularly, the host cells sense the invading bacteria as damage-associated molecular patterns (damps) and pathogen-associated molecular patterns (pamps) by way of various pattern recognition receptors. as a result, the host cells induce alarm signals that activate the inna ...201222407319
effect of bovine lactoferrin on the minimum inhibitory concentrations of ampicillin and trimethoprim-sulfamethoxazole for clinical shigella spp. strains.here, we determined the effect of bovine lactoferrin (blf) on the minimum inhibitory concentration (mic) of ampicillin and trimethoprim-sulfamethoxazole in shigella . using a microdilution method, the mic was determined in the presence or absence of bovine lactoferrin (10 mg/ml) on 88 shigella strains (56 shigella flexneri , 15 shigella boydii , 13 shigella sonnei , and 4 shigella dysenteriae ) previously isolated from peruvian children <2 years old. a fold change of 2 or more in mic values was ...201222397495
antimicrobial and safety properties of lactobacilli isolated from two cameroonian traditional fermented foods.twenty-one lactobacillus isolates from "sha'a" (a maize - based fermented beverage) and "kossam" (traditionally fermented cow milk) were selected in accordance with their antagonistic activities and tested for their bacteriocinogenic potential as well as safety properties. these isolates were preliminarily identified as lactobacillus plantarum (62%), lactobacillus rhamnosus (24%), lactobacillus fermentum (10%) and lactobacillus coprophilus (4%) based on phenotypic characteristics and rep-pcr gen ...201122396914
structure of a type iii secretion needle at 7-å resolution provides insights into its assembly and signaling mechanisms.type iii secretion systems of gram-negative bacteria form injection devices that deliver effector proteins into eukaryotic cells during infection. they span both bacterial membranes and the extracellular space to connect with the host cell plasma membrane. their extracellular portion is a needle-like, hollow tube that serves as a secretion conduit for effector proteins. the needle of shigella flexneri is approximately 50-nm long and 7-nm thick and is made by the helical assembly of one protein, ...201222388746
in vitro microbiological evaluation of 1,1'-(5,5'-(1,4-phenylene)bis(3-aryl-1h-pyrazole-5,1-(4h,5h)-diyl))diethanones, novel bisacetylated pyrazoles.novel 1,1'-(5,5'-(1,4-phenylene)bis(3-aryl-1h-pyrazole-5,1-(4h,5h)-diyl))diethanones 7-12 were tested for their antimicrobial activity by disc diffusion and twofold serial dilution method against the tested bacterial and fungal strains. compounds 7 against micrococcus luteus, 8 against β-heamolytic streptococcus, m. luteus, klebsiella pneumonia, microsporum gypseum, 9 against staphylococcus aureus, shigella flexneri, vibreo cholerae, pseudomonas aeruginosa, aspergillus flavus, mucor indicus, 10 ...201122373408
transmission and strain variation of shigella flexneri 4a after mass prophylaxis in a long-stay psychiatric centre.shigella flexneri 4a caused sustained outbreaks in a large long-stay psychiatric centre, taiwan, 2001-2006. trimethoprim-sulphamethoxazole (sxt) prophylaxis was administered in 2004. we recovered 108 s. flexneri 4a isolates from 83 symptomatic (including one caregiver) and 12 asymptomatic subjects (11 contacts, one caregiver). the isolates were classified into eight antibiogram types and 15 genotypes (six clusters) by using antimicrobial susceptibility testing and pulsed-field gel electrophoresi ...201322364591
antimicrobial-resistant shigella infections from iran: an overlooked problem?in this study, we wanted to assess the level of antimicrobial resistance, the presence of genes encoding resistance to cephalosporins and plasmid-mediated quinolone resistance (pmqr), and genetic relatedness among shigella isolates obtained from iranian patients.201222345385
emergence and stability of high-pressure resistance in different food-borne pathogens.high hydrostatic pressure (hhp) processing is becoming a valuable nonthermal food pasteurization technique, although there is reasonable concern that bacterial hhp resistance could compromise the safety and stability of hhp-processed foods. while the degree of natural hhp resistance has already been shown to vary greatly among and within bacterial species, a still unresolved question remains as to what extent different food-borne pathogens can actually develop hhp resistance. in this study, we t ...201222344661
outer membrane protein a (ompa) of shigella flexneri 2a links innate and adaptive immunity in a tlr2-dependent manner and involvement of il-12 and nitric oxide.we determine that ompa of shigella flexneri 2a is recognized by tlr2 and consequently mediates the release of proinflammatory cytokines and activates nf-κb in hek 293 cells transfected with tlr2. we also observe that in raw macrophages tlr2 is essential to instigate the early immune response to ompa via nf-κb activation and secretion of cytokines and no. consistent with these results, tlr2 knockdown using sirna abolishes the initiation of immune responses. processing and presentation of ompa dep ...201222343631
ethnopharmacological study of plants from pondoland used against diarrhoea.waterborne diseases such as diarrhoea are common world wide, including in bizana, south africa where the majority of rural dwellers depend largely on water from unprotected sources. the people from bizana use medicinal plants as their first line of health care to cure and prevent diarrhoea.201222338648
distinct roles of secreted htra proteases from gram-negative pathogens in cleaving the junctional protein and tumor suppressor e-cadherin.the periplasmic chaperone and serine protease htra is important for bacterial stress responses and protein quality control. recently, we discovered that htra from helicobacter pylori is secreted and cleaves e-cadherin to disrupt the epithelial barrier, but it remained unknown whether this maybe a general virulence mechanism. here, we show that important other pathogens including enteropathogenic escherichia coli, shigella flexneri, and campylobacter jejuni, but not neisseria gonorrhoeae, cleaved ...201222337879
emergence of resistance to fluoroquinolones and third-generation cephalosporins in shigella flexneri subserotype 1c isolates from china.we report here on the first identification of shigella flexneri subserotype 1c in china. we also report the emergence of resistance to ciprofloxacin and third-generation cephalosporins in this subserotype 1c for the first time. isolates of seven strains circulating in china yielded three new sequence types and seven pulsed-field gel electrophoresis patterns, thus demonstrating the existence of high genetic diversity within the isolates. overall, the seven isolates showed reduced susceptibility t ...201222329572
the structures of coiled-coil domains from type iii secretion system translocators reveal homology to pore-forming toxins.many pathogenic gram-negative bacteria utilize type iii secretion systems (t3sss) to alter the normal functions of target cells. shigella flexneri uses its t3ss to invade human intestinal cells to cause bacillary dysentery (shigellosis) that is responsible for over one million deaths per year. the shigella type iii secretion apparatus is composed of a basal body spanning both bacterial membranes and an exposed oligomeric needle. host altering effectors are secreted through this energized unidire ...201222321794
recognition of enteroinvasive escherichia coli and shigella flexneri by dendritic cells: distinct dendritic cell activation states.the innate and adaptive immune responses of dendritic cells (dcs) to enteroinvasive escherichia coli (eiec) infection were compared with dc responses to shigella flexneri infection. eiec triggered dcs to produce interleukin (il)-10, il-12 and tumour necrosis factor (tnf)-α, whereas s. flexneri induced only the production of tnf-α. unlike s. flexneri, eiec strongly increased the expression of toll like receptor (tlr)-4 and tlr-5 in dcs and diminished the expression of co-stimulatory molecules tha ...201222310548
icsa autotransporter passenger promotes increased fusion protein expression on the cell surface.autotransporters are attractive cell surface display vehicles as they lack complex adaptor proteins necessary for protein export. recent reports have suggested that the native effector domain (α domain) and translocation domain (β domain) interact with each other to drive translocation of the effector domain to the outer membrane. in this report we compared the expression, surface localisation and folding of tem-1 β-lactamase (bla) and maltose binding protein (male or mbp) fused to either full l ...201222309506
characterization of sfpgda, a shigella flexneri peptidoglycan deacetylase required for bacterial persistence within polymorphonuclear neutrophils.peptidoglycan deacetylases protect the gram-positive bacteria cell wall from host lysozymes by deacetylating peptidoglycan. sequence analysis of the genome of shigella flexneri predicts a putative polysaccharide deacetylase encoded by the plasmidic gene orf185, renamed here sfpgda. we demonstrated a peptidoglycan deacetylase (pgd) activity with the purified sfpgda in vitro. to investigate the role sfpgda in virulence, we constructed a sfpgda mutant and studied its phenotype in vitro. the mutant ...201222307019
an expert panel report of a proposed scientific model demonstrating the effectiveness of antibacterial handwash products.in 2005, a us food and drug administration nonprescription drug advisory committee (ndac) review of consumer antiseptic handwash product studies concluded that the data regarding existing products failed to demonstrate any association between specific log reductions of bacteria achieved by antiseptic handwashing and reduction of infection. the ndac recommended that consumer antibacterial handwashing products should demonstrate a reduction in infection compared with non-antibacterial handwash pro ...201222300895
milk microbiome signatures of subclinical mastitis-affected cattle analysed by shotgun sequencing.metagenomic analysis of milk samples collected from kankrej, gir (bos indicus) and crossbred (bos taurus × b. indicus) cattle harbouring subclinical mastitis was carried out by next-generation sequencing 454 gs-flx technology to elucidate the microbial community structure of cattle milk.201222277077
development and evaluation of a multiplex pcr for simultaneous detection of five foodborne pathogens.to develop a rapid multiplex pcr method for simultaneous detection of five major foodborne pathogens (staphylococcus aureus, listeria monocytogenes, escherichia coli o157:h7, salmonella enteritidis and shigella flexneri, respectively).201222268759
shigella flexneri encephalopathy in a male child. 200622266506
antimicrobial activity of ulopterol isolated from toddalia asiatica (l.) lam.: a traditional medicinal plant.aim of the study: the leaves of toddalia asiatica (l.) lam. (rutaceae) are widely used in folk medicine in india to treat various ailments. in our earlier communication we have reported the antimicrobial study on the various extracts of the leaves and the isolation and identification of flindersine, a quinolone alkaloid as the major active principle. in the present study, we report the antibacterial and antifungal activities of ulopterol, a coumarin isolated as another major active antimicrobial ...201222265751
interaction of mxig with the cytosolic complex of the type iii secretion system controls shigella virulence.gram-negative bacteria use the type 3 secretion system (t3ss) to colonize host cells. t3sss are ring-shaped macromolecular complexes specific for the transport of effector molecules into host cells. it was recently suggested that a cytosolic ring-shaped protein complex delivers effector molecules to the t3ss. however, how transport of effector proteins is regulated is not known. here, we report the high-resolution x-ray crystal structure of the whole cytosolic domain of mxig (mxig(1-126)), a maj ...201222247334
shigella flexneri infection in a newly acquired rhesus macaque (macaca mulatta).a 3.4 year-old rhesus macaque weighing 4.5 kg, was suffering from anorexia, acute mucous and bloody diarrhea. on physical examination, the monkey showed a loss of activity, hunched posture, abdominal pain, dehydration, mild gingivitis and unclean anus with discharge. whole blood was collected for the examination of electrolytes, hematology and serum chemistry; fresh stool was also collected for bacterial culture. blood profiles showed leukocytosis (14.5 k/µl) and neutrophilia (11.0 k/µl) on comp ...201122232644
Genesis of a novel Shigella flexneri serotype by sequential infection of serotype-converting bacteriophages SfX and SfI.ABSTRACT: BACKGROUND: Shigella flexneri is the major pathogen causing bacillary dysentery. Fifteen serotypes have been recognized up to now. The genesis of new S. flexneri serotypes is commonly mediated by serotype-converting bacteriophages. Untypeable or novel serotypes from natural infections had been reported worldwide but have not been generated in laboratory. RESULTS: A new S. flexneri serotype-serotype 1 d was generated when a S. flexneri serotype Y strain (native LPS) was sequentially in ...201122208551
emergence of ceftriaxone resistant shigella.shigellosis is endemic in many resource-poor countries due to feco-oral transmission, resulting in considerable morbidity and mortality. there is rapid emergence of multi-drug resistant (mdr) shigella spp. resulting in poor reliability of first line antibiotics like quinolones, co-trimoxazole and ampicillin. ceftriaxone has been used as a reserved antibiotic for treatment of mdr shigella spp. the authors report a case of ceftriaxone resistant shigella flexneri successfully managed with meropenem ...201122205379
a broadly protective shigella vaccine based on type iii secretion apparatus proteins.shigella ssp. are food and water-borne pathogens that cause severe diarrheal and dysenteric disease associated with high morbidity and mortality. individuals most often affected are children under 5 years of age in the developing world. the existence of multiple shigella serotypes and the heterogenic distribution of pathogenic strains as well as emerging antibiotic resistance require the development of a broadly protective vaccine. all shigella ssp. utilize a type iii secretion system (ttss) to ...201122202122
topological characterisation and identification of critical domains within glucosyltransferase iv (gtriv) of shigella flexneri.abstract:201122188643
synthesis and biological evaluation of some thiazolidinones as antimicrobial agents.a novel series of thiazolidinone derivatives namely 4-(4-dimethylamino-6-{4-[5-(4-ethylpiperazin-1-ylmethyl)-4-oxo-2-phenylthiazolidin-3-yl]-phenylamino}-[1,3,5]triazin-2-yloxy)-1-methyl-1h-quinolin-2-one have been synthesized from the key intermediate 4-[4-(4-aminophenylamino)-6-dimethylamino-[1,3,5]triazin-2-yloxy]-1-methyl-1h-quinolin-2-one (7). condensation reaction of compound 7 with different aldehyde derivatives were performed to obtain schiff base derivatives, which after cyclization gav ...201122182927
reflectron maldi tof and maldi tof/tof mass spectrometry reveal novel structural details of native lipooligosaccharides.lipooligosaccharides (los) are powerful gram-negative glycolipids that evade the immune system and invade host animal and vegetal cells. the structural elucidation of los is pivotal to understanding the mechanisms of infection at the molecular level. the amphiphilic nature of los has been the main obstacle for structural analysis by matrix-assisted laser desorption/ionization (maldi) mass spectrometry (ms). our approach has resolved this important issue and has permitted us to obtain reflectron ...201122124985
neurological manifestations of shigellosis in children in southwestern iran. 201122115119
analysis of synonymous codon usage in shigella flexneri 2a strain 301 and other shigella and escherichia coli strains.in this study, we analysed synonymous codon usage in shigella flexneri 2a strain 301 (sf301) and performed a comparative analysis of synonymous codon usage patterns in sf301 and other strains of shigella and escherichia coli. although there was a significant variety in codon usage bias among different sf301 genes, there was a slight but observable codon usage bias that could primarily be attributable to mutational pressure and translational selection. in addition, the relative abundance of dinuc ...201122112197
up-regulation of muc2 and il-1β expression in human colonic epithelial cells by shigella and its interaction with mucins.the entire gastrointestinal tract is protected by a mucous layer, which contains complex glycoproteins called mucins. muc2 is one such mucin that protects the colonic mucosa from invading microbes. the initial interaction between microbes and mucins is an important step for microbial pathogenesis. hence, it was of interest to investigate the relationship between host (mucin) and pathogen interaction, including shigella induced expression of muc2 and il-1β during shigellosis.201122073249
[Etiological aspects of acute gastroenteritis--a ten-year review (1.01. 2001-31.12.2010)].Acute gastroentritis is one of the most common diseases in humans, and continues to be a significant cause of morbidity worldwide.201122046776
bacterial aetiology of diarrhoeal diseases and antimicrobial resistance in dhaka, bangladesh, 2005-2008.summaryinfectious diarrhoea caused by bacterial pathogens contributes to the high level of mortality in developing countries like bangladesh. following standard bacteriological procedures, a total of 14 428 bacterial pathogens were isolated from 56 132 stool samples and rectal swabs collected from diarrhoeal patients between 2005 and 2008. the rate of isolation and antimicrobial susceptibility data were retrospectively analysed for these isolates and among them vibrio spp. (42·9%) were the most ...201122040529
Crystal Structure of the VapBC Toxin-Antitoxin Complex from Shigella flexneri Reveals a Hetero-Octameric DNA-Binding Assembly.Toxin-antitoxin (TA) loci are common in archaea and prokaryotes and allow cells to rapidly adapt to changing environmental conditions through release of active regulators of metabolism. Many toxins are endonucleases that target cellular mRNA and tRNAs, while the antitoxins tightly wrap around the toxins to inhibit them under normal circumstances. The antitoxins also bind to operators in the promoter regions of the cognate TA operon and thereby regulate transcription. For enteric vapBC TA loci, t ...201122037005
a proteogenomic analysis of shigella flexneri using 2d lc-maldi tof/tof.new strategies for high-throughput sequencing are constantly appearing, leading to a great increase in the number of completely sequenced genomes. unfortunately, computational genome annotation is out of step with this progress. thus, the accurate annotation of these genomes has become a bottleneck of knowledge acquisition.201122032405
the role of oxyr and soxrs in oxidative stress survival in shigella flexneri.shigella flexneri, a facultative intracellular pathogen, is exposed to a variety of environments inside and outside of the human host. some of these environments may contain significant oxidative stress. s. flexneri mutants were generated with deletions in the major oxidative stress regulators oxyr and/or soxrs to test their importance in shigella biology. strains that contained a deletion of oxyr had reduced growth and survival during aerobic growth, but not microaerobic growth. the mutants wer ...201122015257
Morning Glory Resin Glycosides as Modulators of Antibiotic Activity in Multidrug-Resistant Gram-Negative Bacteria.Twenty-six microbiologically inactive (MIC >?512?µg/mL) convolvulaceous resin glycosides ( 1- 26) were tested for resistance modulatory activity IN VITRO against ESCHERICHIA COLI Rosetta-gami and two nosocomial pathogens, SALMONELLA TYPHI and SHIGELLA FLEXNERI. These compounds exerted a potentiation effect of the clinically useful antibiotics tetracycline, kanamycin, and chloramphenicol against the tested gram-negative bacteria by increasing antibiotic susceptibility up to 32-fold at concent ...201122002849
antisense inhibition of gene expression and growth in gram-negative bacteria by cell-penetrating peptide conjugates of peptide nucleic acids targeted to rpod gene.gram-negative bacteria (gnb) cause common and severe hospital- and community-acquired infections with a high incidence of multidrug resistance (mdr) and mortality. the emergence and spread of mdr-gnb strains limit therapeutic options and highlight the need to develop new therapeutic strategies. in this study, the peptide (rxr)(4)xb- and (kff)(3)k-conjugated peptide nucleic acids (ppnas) were developed to target rpod, which encodes an rna polymerase primary σ(70) that is thought to be essential f ...201122000398
Molecular mechanism of multi-drug resistance in Shigella isolates from rural China.Diarrhoeal diseases and enteric infections are major causes of morbidity and mortality in the developing countries. Shigellosis was sixth in the rank of death caused by infectious disease in China. Present study assess the patterns of antimicrobial susceptibility and mutations in marA genes of Shigella isolates and its association. One hundred isolates of Shigella spp were tested to evaluate the antimicrobial susceptibility and mutation of marA through PCR-SSCP. The antimicrobial resistance prof ...201121991697
contribution of the lipopolysaccharide to resistance of shigella flexneri 2a to extreme acidity.shigella flexneri is endemic in most underdeveloped countries, causing diarrheal disease and dysentery among young children. in order to reach its target site, the colon, shigella must overcome the acid environment of the stomach. shigella is able to persist in this stressful environment and, because of this ability it can initiate infection following the ingestion of very small inocula. thus, acid resistance is considered an important virulence trait of this bacterium. it has been reported that ...201121984920
interaction of concanavalin a with bacterial lipopolysaccharides in agarose gel.binding of fluorescein isothiocyanate-labeled concanavalin a to a series of molecular species of lipopolysaccharide (lps), purified from pathogenic bacteria, was studied via agarose gel precipitation experiments and the results were compared with available structural data.the lps species could be divided into cona-reactive and non-reactive ones. reactivity resided in the o-specific chain of lps, and binding to the lipid a or core moieties of lps could not be demonstrated by the present methods. ...201121983321
a 35 kda antigenic protein from shigella flexneri: in silico structural and functional studies.shigella flexneri serotype 2a is a major public health concern in the developing and under-developed countries which contributes to shigellosis endemic and mortality. thus, there is an urgent need for a rapid diagnostic test for effective therapy and disease management. previous study showed that a ∼35 kda antigenic protein from s. flexneri is a potential biomarker. we therefore modelled the three-dimensional structure of the antigen to probe its functionality which could aid in the development ...201121982766
Investigation of the binding of a carbohydrate-mimetic peptide to its complementary anticarbohydrate antibody by STD-NMR spectroscopy and molecular-dynamics simulations.Saturation transfer difference (STD)-NMR spectroscopy was used to probe experimentally the bioactive solution conformation of the carbohydrate mimic MDWNMHAA 1 of the O-polysaccharide of Shigella flexneri Y when bound to its complementary antibody, mAb SYA/J6. Molecular dynamics simulations using the ZymeCAD™ Molecular Dynamics platform were also undertaken to give a more accurate picture of the conformational flexibility and the possibilities for bound ligand conformations. The ligand topology, ...201121953925
shigella flexneri infection generates the lipid pi5p to alter endocytosis and prevent termination of egfr signaling.the phosphoinositide metabolic pathway, which regulates cellular processes implicated in survival, motility, and trafficking, is often subverted by bacterial pathogens. shigella flexneri, a bacterium that causes dysentery, injects ipgd, a phosphoinositide phosphatase that generates the lipid phosphatidylinositol 5-phosphate (pi5p), into host cells, thereby activating the phosphoinositide 3-kinase-akt survival pathway. we show that epidermal growth factor receptor (egfr) is required for pi5p-depe ...201121934107
Sepsis-related myocardial calcification. 201121934087
Mucosal immunization with Shigella flexneri outer membrane vesicles induced protection in mice.Vaccination appears to be the only rational prophylactic approach to control shigellosis. Unfortunately, there is still no safe and efficacious vaccine available. We investigated the protection conferred by a new vaccine containing outer membrane vesicles (OMVs) from Shigella flexneri with an adjuvant based on nanoparticles in an experimental model of shigellosis in mice. OMVs were encapsulated in poly(anhydride) nanoparticles prepared by a solvent displacement method with the copolymer PMV/MA. ...201121911022
waterlogsy nmr experiments in conjunction with molecular-dynamics simulations identify immobilized water molecules that bridge peptide mimic mdwnmhaa to anticarbohydrate antibody sya/j6.x-ray crystallographic data of the carbohydrate mimic mdwnmhaa when bound to an anti-shigella flexneri y mab sya/j6 indicate the immobilization of water molecules, that is, the presence of "bound" waters, in the active site. water ligand observed via gradient spectroscopy (waterlogsy) was used in conjunction with saturation transfer difference (std)-nmr spectroscopy to probe the existence of immobilized water molecules in the complex of mdwnmhaa 1 bound to mab sya/j6. molecular dynamics simulati ...201121887835
Development of a multiplex PCR assay targeting O-antigen modification genes for molecular serotyping of Shigella flexneri.Shigella flexneri is the major Shigella species that causes diarrheal disease in developing countries. It is further subdivided into 15 serotypes based on O-antigen structure. Serotyping of S. flexneri is important for epidemiological purposes. In this study, we developed a multiplex PCR assay targeting the O-antigen synthesis gene wzx and the O-antigen modification genes gtrI, gtrIC, gtrII, oac, gtrIV, gtrV, and gtrX for molecular serotyping of S. flexneri. The multiplex PCR assay contained eig ...201121880974
rational design of an artificial genetic switch: co-option of the h-ns-repressed prou operon by the virb virulence master regulator.the h-ns protein represses the transcription of hundreds of genes in gram-negative bacteria. derepression is achieved by a multitude of mechanisms, many of which involve the binding of a protein to dna at the repressed promoter in a manner that compromises the maintenance of the h-ns-dna nucleoprotein repression complex. the principal virulence gene promoters in shigella flexneri, the cause of bacillary dysentery, are repressed by h-ns. virb, a protein that closely resembles members of the parb ...201121873493
antimicrobial and toxicological activities of five medicinal plant species from cameroon traditional medicine.infectious diseases caused by multiresistant microbial strains are on the increase. fighting these diseases with natural products may be more efficacious. the aim of this study was to investigate the in vitro antimicrobial activity of methanolic, ethylacetate (etoac) and hexanic fractions of five cameroonian medicinal plants (piptadeniastum africana, cissus aralioides, hileria latifolia, phyllanthus muellerianus and gladiolus gregasius) against 10 pathogenic microorganisms of the urogenital and ...201121867554
The iron-responsive Fur/RyhB regulatory cascade modulates the Shigella outer membrane protease IcsP.Actin-based motility is central to the pathogenicity of the intracellular bacterial pathogen Shigella. Two Shigella outer membrane proteins, IcsA and IcsP, are required for efficient actin-based motility in the host cell cytoplasm, and the genes encoding both proteins are carried on the large virulence plasmid. IcsA triggers actin polymerization on the surface of the bacterium, leading to the formation of an actin tail that allows both intra- and intercellular spread. IcsP, an outer membrane pro ...201121859852
wide dissemination of multidrug-resistant shigella isolates in china.to evaluate the prevalence of antimicrobial resistance and selected antimicrobial resistance mechanisms in shigella isolates recovered in outpatients from 1997 to 2009 in china.201121859815
the effect of the potential phoq histidine kinase inhibitors on shigella flexneri virulence.phoq/phop is an important two-component system that regulates shigella virulence. we explored whether the phoq/phop system is a promising target for new antibiotics against s. flexneri infection. by using a high-throughput screen and enzymatic activity coupled assay, four compounds were found as potential phoq inhibitors. these compounds not only inhibited the activity of sf-phoqc autophosphorylation but also displayed high binding affinities to the sf-phoqc protein in the surface plasmon resona ...201121853073
recovery and characterization of environmental variants of shigella flexneri from surface water in bangladesh.little is known about the distribution, survival, and transmission of shigella in environmental surface waters. to gain more insight into the environmental biology of shigella we isolated five bacterial strains serotyped as shigella flexneri 2b from a freshwater lake in bangladesh using a modified nutrient broth supplemented with nucleic acid bases. the biochemical properties of the isolates, including inability to ferment lactose and a negative lysine decarboxylase test, indicated common physio ...201121826486
outer membrane protein a (ompa) of shigella flexneri 2a, induces protective immune response in a mouse model.in our earlier studies 34 kda outer membrane protein (omp) of shigella flexneri 2a has been identified as an efficient immunostimulant.201121818362
the future is cold: cryo-preparation methods for transmission electron microscopy of cells.our knowledge of the organization of the cell is linked, to a great extent, to light and electron microscopy. choosing either photons or electrons for imaging has many consequences on the image obtained, as well as on the experiment required in order to generate the image. one apparent effect on the experimental side is in the sample preparation, which can be quite elaborate for electron microscopy. in recent years, rapid freezing, cryo-preparation and cryo-electron microscopy have been more wid ...201121812762
the vibrio cholerae vctpdgc system transports catechol siderophores and a siderophore-free iron ligand.vibrio cholerae, the causative agent of cholera, has an absolute requirement for iron. it transports the catechol siderophores vibriobactin, which it synthesizes and secretes, and enterobactin. these siderophores are transported across the inner membrane by one of two periplasmic binding protein-dependent abc transporters, vctpdgc or viupdgc. we show here that one of these inner membrane transport systems, vctpdgc, also promotes iron acquisition in the absence of siderophores. plasmids carrying ...201121790806
safety, and immunogenicity of an intranasal shigella flexneri 2a invaplex 50 vaccine.background: shigella flexneri 2a invaplex 50 is a nasally delivered subunit vaccine consisting of a macromolecular complex composed of lps, ipab, ipac and ipad. the current study examined vaccine safety and immunogenicity across a dose range and the clinical performance of a new intranasal delivery device. methods: volunteers (n=36) were randomized to receive vaccine via the dolphin™ (valois of america, congers, new york) intranasal spray device at one of three doses (240, 480, and 690µg) on day ...201121787825
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