Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| the serine protease pic from enteroaggregative escherichia coli mediates immune evasion by the direct cleavage of complement proteins. | enteroaggregative and uropathogenic escherichia coli, shigella flexneri 2a, and the hybrid enteroaggregative/shiga toxin-producing e. coli strain (o104:h4) are important pathogens responsible for intestinal and urinary tract infections, as well as sepsis and hemolytic uremic syndrome. they have in common the production of a serine protease called pic. several biological roles for pic have been described, including protection of e. coli dh5α from complement-mediated killing. hereby we showed that ... | 2015 | 25583166 |
| [preparation and identification of the polyclonal antibody against heat shock protein 70 (dnak) from shigella flexneri 5a m90t]. | to generate polyclonal antibodies against shigella flexneri 5a m90t heat shock protein 70 (dnak) and identify the specificity and titer of antibodies. | 2015 | 25575068 |
| short communication: in vitro assessment of antioxidant, antibacterial and phytochemical analysis of peel of citrus sinensis. | antibacterial effect of citrus sinensis peel extracts was evaluated against several pathogenic bacteria associated with human and fish infections viz., escherichia coli, pseudomonas aeruginosa, klebsiella pneumonia, staphylococcus aureus, streptococcus pyogenes, staphylococcus epidermidis, serratia marcesnces, shigella flexneri, enterobacter amnigenus, salmonella typhimurium and serratia odorifera. methanol, ethanol, chloroform and diethyl ether solvents were used for extraction. in vitro antiba ... | 2015 | 25553700 |
| characterization and bioactivities of an exopolysaccharide produced by lactobacillus plantarum yw32. | the exopolysaccharide (eps) produced by lactobacillus plantarum yw32 was purified and characterized, and the in vitro bioactivities of the purified eps were also evaluated. the eps had a molecular weight of 1.03×10(5) da, and it consisted of mannose, fructose, galactose and glucose in an approximate molar ratio of 8.2:1:4.1:4.2. microstructural studies of the eps demonstrated a web-like structure composed of compact ropes, and presence of many homogeneous rod-shaped lumps. the eps also showed hi ... | 2015 | 25532782 |
| prediction of intra-species protein-protein interactions in enteropathogens facilitating systems biology study. | protein-protein interactions in escherichia coli (e. coli) has been studied extensively using high throughput methods such as tandem affinity purification followed by mass spectrometry and yeast two-hybrid method. this can in turn be used to understand the mechanisms of bacterial cellular processes. however, experimental characterization of such huge amount of interactions data is not available for other important enteropathogens. here, we propose a support vector machine (svm)-based prediction ... | 2015 | 26717407 |
| microbial contamination of street vended foods from a university campus in bangladesh. | the microbiological quality of street vended food samples from dhaka, bangladesh was evaluated. the objective of the study was to identify the presence of common pathogens (escherichia coli, shigella spp, salmonella and vibrio spp) and to describe the molecular characterization of e coli, a commonly found pathogen in various street foods. fifty food samples were collected from fixed and mobile vendors from two sampling locations (mohakhali and aftabnagar) in dhaka city, bangladesh. the tested sa ... | 2015 | 26521522 |
| antimicrobial activity and the presence of virulence factors and bacteriocin structural genes in enterococcus faecium cm33 isolated from ewe colostrum. | screening of lactic acid bacteria (lab) isolated from ewe colostrum led to the identification and isolation of enterococcus faecium cm33 with interesting features like high survival rates under acidic or bile salts condition, high tolerance for the simulated gastrointestinal condition, and high adhesive potential to caco-2 cells. according the inhibition of pathogen adhesion test results, this strain can reduce more than 50% adhesion capacity of escherichia coli, shigella flexneri, klebsiella pn ... | 2015 | 26284059 |
| notes from the field: outbreak of diarrheal illness caused by shigella flexneri - american samoa, may-june 2014. | on may 9, 2014, a physician at hospital a in american samoa noticed an abnormally high number of children presenting to the emergency department with bloody diarrhea. based on preliminary testing of stool specimens, entamoeba histolytica infection was suspected as a possible cause. shigella was also suspected in a subset of samples. on may 22, the american samoa department of health requested assistance from cdc with the outbreak investigation. the goals of the investigation were to establish th ... | 2015 | 25590684 |
| attributes of carbapenemase encoding conjugative plasmid pndm-sal from an extensively drug-resistant salmonella enterica serovar senftenberg. | a carbapenem resistant salmonella enterica serovar senftenberg isolate bch 2406 was isolated from a diarrheal child attending an outpatient unit of b.c. roy hospital in kolkata, india. this isolate was positive for the bla ndm-1 in the pcr assay, which was confirmed by amplicon sequencing. except for tetracycline, this isolate was resistant to all the tested antimicrobials. the bla ndm-1 was found to be located on a 146.13-kb mega plasmid pndm-sal, which could be conjugally transferred into esch ... | 2015 | 26441902 |
| antibacterial activity of lactobacillus spp. isolated from the feces of healthy infants against enteropathogenic bacteria. | lactobacilli are normal microflora of the gastrointestinal (gi) tract and are a heterogeneous group of lactic acid bacteria (lab). lactobacillus strains with probiotic activity may have health benefits for human. this study investigates the probiotic potential of lactobacillus strains obtained from the feces of healthy infants and also explores antibacterial activity of lactobacillus strains with probiotic potential against enteropathogenic bacteria. fecal samples were collected from 95 healthy ... | 2015 | 25930687 |
| development of a multi-pathogen enrichment broth for simultaneous growth of five common foodborne pathogens. | the objective of the present study was to formulate a multi-pathogen enrichment broth which could support the simultaneous growth of five common foodborne pathogens (salmonella enterica, staphylococcus aureus, shigella flexneri, listeria monocytogenes and escherichia coli o157:h7). the formulated broth sssle was composed of potassium tellurite, bile salt, lithium chloride, and sodium chloride as growth-inhibitors; glucose, esculin, mannitol and sodium pyruvate as growth-promoters. compared with ... | 2015 | 26782652 |
| bacterial spread from cell to cell: beyond actin-based motility. | several intracellular pathogens display the ability to propagate within host tissues by displaying actin-based motility in the cytosol of infected cells. as motile bacteria reach cell-cell contacts they form plasma membrane protrusions that project into adjacent cells and resolve into vacuoles from which the pathogen escapes, thereby achieving spread from cell to cell. seminal studies have defined the bacterial and cellular factors that support actin-based motility. by contrast, the mechanisms s ... | 2015 | 26021574 |
| the class ii phosphatidylinositol 3-phosphate kinase pik3c2a promotes shigella flexneri dissemination through formation of vacuole-like protrusions. | intracellular pathogens such as shigella flexneri and listeria monocytogenes achieve dissemination in the intestinal epithelium by displaying actin-based motility in the cytosol of infected cells. as they reach the cell periphery, motile bacteria form plasma membrane protrusions that resolve into vacuoles in adjacent cells, through a poorly understood mechanism. here, we report on the role of the class ii phosphatidylinositol 3-phosphate kinase pik3c2a in s. flexneri dissemination. time-lapse mi ... | 2015 | 25667265 |
| the n terminus of type iii secretion needle protein yscf from yersinia pestis functions to modulate innate immune responses. | the type iii secretion system is employed by many pathogens, including the genera yersinia, shigella, pseudomonas, and salmonella, to deliver effector proteins into eukaryotic cells. the injectisome needle is formed by the polymerization of a single protein, e.g., yscf (yersinia pestis), pscf (pseudomonas aeruginosa), prgi (salmonella enterica spi-1), ssag (salmonella enterica spi-2), or mxih (shigella flexneri). in this study, we demonstrated that the n termini of some needle proteins, particul ... | 2015 | 25644012 |
| isolation and development of bioluminescent reporter phages for bacterial dysentery. | shigellosis is a significant cause of morbidity and mortality worldwide, most notably amongst children. moreover, there is a global increase in the occurrence of multidrug-resistant isolates, including the epidemic and pandemic shigella dysenteriae type 1 strain. we developed a bioluminescent reporter phage assay to facilitate detection and simultaneously determine antibiotic susceptibility. a shigella flexneri phage (shfl25875) was isolated from environmental wastewater and characterized by dna ... | 2015 | 25252629 |
| intracellular and membrane-damaging activities of methyl gallate isolated from terminalia chebula against multidrug-resistant shigella spp. | shigella spp. (shigella dysenteriae, shigella flexneri, shigella boydii and shigella sonnei) cause bacillary dysentery (shigellosis), which is characterized by bloody mucous diarrhoea. although a variety of antibiotics have been effective for treatment of shigellosis, options are becoming limited due to globally emerging drug resistance. in the present study, in vitro antibacterial activity of methyl gallate (mg) isolated from terminalia chebula was determined by performing mic, minimal bacteric ... | 2015 | 26272388 |
| shigella outer membrane protein pssp-1 is broadly protective against shigella infection. | in developing countries, shigella is a primary cause of diarrhea in infants and young children. although antibiotic therapy is an effective treatment for shigellosis, therapeutic options are narrowing due to the emergence of antibiotic resistance. thus, preventive vaccination could become the most efficacious approach for controlling shigellosis. we have identified several conserved protein antigens that are shared by multiple shigella serotypes and species. among these, one antigen induced cros ... | 2015 | 25651919 |
| molecular characterization of multidrug-resistant shigella spp. of food origin. | shigella spp. are the causative agents of food-borne shigellosis, an acute enteric infection. the emergence of multidrug-resistant clinical isolates of shigella presents an increasing challenge for clinicians in the treatment of shigellosis. several studies worldwide have characterized the molecular basis of antibiotic resistance in clinical shigella isolates of human origin, however, to date, no such characterization has been reported for shigella spp. of food origin. in this study, we characte ... | 2015 | 25485847 |
| biophysical characterization of the type iii secretion tip proteins and the tip proteins attached to bacterium-like particles. | bacterium-like particles (blps), derived from lactococcus lactis, offer a self-adjuvanting delivery vehicle for subunit protein vaccines. proteins can be specifically loaded onto the blps via a peptidoglycan anchoring (pa) domain. in this study, the tip proteins ipad, sipd, and lcrv belonging to type iii secretion systems of shigella flexneri, salmonella enterica, and yersinia enterocolitica, respectively, were fused to the pa and loaded onto the blps. herein, we biophysically characterized thes ... | 2015 | 24916512 |
| [analysis of the drug resistance and the integron resistance gene cassette's characteristics of shigella flexneri]. | to investigate the correlation between shigella flexneri multi-drug resistance and drug resistance gene cassette of integrons. | 2015 | 26758113 |
| comparative proteomics of shigella flexneri 2a strain 301 using a rabbit ileal loop model reveals key proteins for bacterial adaptation in host niches. | many studies focusing on changes in the host following shigella spp invasion have been reported in recent years. however, the key factors required for the adaptation of these pathogens to host niches have usually been neglected. | 2015 | 26417879 |
| identification of shigella flexneri isolates carrying the shiga toxin 1-producing gene in quebec, canada, linked to travel to haiti. | 2015 | 26401981 | |
| vasodilator-stimulated phosphoprotein restricts cell-to-cell spread of shigella flexneri at the cell periphery. | shigella spp. are intracellular bacterial pathogens that cause diarrhoeal disease in humans. shigella utilize the host actin cytoskeleton to enter cells, move through the cytoplasm of cells and pass into adjacent cells. ena/vasp family proteins are highly conserved proteins that participate in actin-dependent dynamic cellular processes. we tested whether ena/vasp family members vasp (vasodilator-stimulated phosphoprotein), mena (mammalian-enabled) or evl (ena-vasp-like) contribute to shigella fl ... | 2015 | 26358985 |
| shigellosis outbreak in al batinah south governorate, oman: case-control study. | an outbreak of acute gastroenteritis due to shigella flexneri occurred in august 2012 in the catchment area of the wadi sahtan health center in rustaq, al batinah south governorate, oman. the aim of this study was to discover possible causes of this outbreak in the villages of fassa, rogh and amk and to measure the risk of exposure among cases and controls. | 2015 | 26357558 |
| mechanism of action and initial, in vitro sar of an inhibitor of the shigella flexneri virulence regulator virf. | shigella spp. are among the main causative agents of acute diarrheal illness and claim more than 1 million lives per year worldwide. there are multiple bacterial genes that control the pathogenesis of shigella, but the virf gene may be the most important. this gene, located on the primary pathogenicity island of shigella, encodes virf, an arac-family transcriptional activator that is responsible for initiating the pathogenesis cycle in shigella. we have previously shown that it is possible to at ... | 2015 | 26352269 |
| investigation on the synthesis of shigella flexneri specific oligosaccharides using disaccharides as potential transglucosylase acceptor substrates. | chemo-enzymatic strategies hold great potential for the development of stereo- and regioselective syntheses of structurally defined bioactive oligosaccharides. herein, we illustrate the potential of the appropriate combination of a planned chemo-enzymatic pathway and an engineered biocatalyst for the multistep synthesis of an important decasaccharide for vaccine development. we report the stepwise investigation, which led to an efficient chemical conversion of allyl α-d-glucopyranosyl-(1→4)-α-l- ... | 2015 | 26340432 |
| a small conserved motif supports polarity augmentation of shigella flexneri icsa. | the rod-shaped enteric intracellular pathogen shigella flexneri and other shigella species are the causative agents of bacillary dysentery. s. flexneri are able to spread within the epithelial lining of the gut, resulting in lesion formation, cramps and bloody stools. the outer membrane protein icsa is essential for this spreading process. icsa is the initiator of an actin-based form of motility whereby it allows the formation of a filamentous actin 'tail' at the bacterial pole. importantly, ics ... | 2015 | 26315462 |
| determinants of proteolysis and cell-binding for the shigella flexneri cytotoxin, siga. | shigella flexneri secretes an enterotoxic, spate family autotransporter (at), siga, which has cytopathic activity towards cultured epithelial cells. its cytopathic activity is due to its ability to degrade the cytoskeletal protein, α-fodrin. the mechanisms by which at toxins target cells and tissues differ and the details of how siga acts are not known. in the current study, the determinants of proteolysis and cell-targeting for siga were determined. we demonstrate that the siga passenger or α-d ... | 2015 | 26297175 |
| detection of wzy/wzz interaction in shigella flexneri. | the o antigen (oag) component of shigella flexneri lipopolysaccharide (lps) is important for virulence and a protective antigen. it is synthesized by the wzy-dependent mechanism. s. flexneri wzy has 12 transmembrane segments and two large periplasmic loops. the modal chain length of the oag is determined by wzz. experimental evidence supports multi-protein interactions in the wzy-dependent pathway. however, evidence for direct interaction of wzy with the other proteins of the wzy-dependent pathw ... | 2015 | 26296569 |
| quantification of cytosolic vs. vacuolar salmonella in primary macrophages by differential permeabilization. | intracellular bacterial pathogens can replicate in the cytosol or in specialized pathogen-containing vacuoles (pcvs). to reach the cytosol, bacteria like shigella flexneri and francisella novicida need to induce the rupture of the phagosome. in contrast, salmonella typhimurium replicates in a vacuolar compartment, known as salmonella-containing vacuole (scv). however certain mutants of salmonella fail to maintain scv integrity and are thus released into the cytosol. the percentage of cytosolic v ... | 2015 | 26274778 |
| sting signaling the energic way. | the effector proteins ipaj and vira, from the bacterium shigella flexneri, block the general secretory pathway (gsp) at different stages. in this issue of cell host & microbe, dobbs et al. (2015) use these proteins as a tool to pinpoint sting trafficking and signaling to the er-golgi intermediate compartment (ergic). | 2015 | 26269948 |
| mutations in gyra & parc genes of shigella flexneri 2a determining the fluoroquinolone resistance. | 2015 | 26205028 | |
| bacterial internalization, localization, and effectors shape the epithelial immune response during shigella flexneri infection. | intracellular pathogens are differentially sensed by the compartmentalized host immune system. nevertheless, gene expression studies of infected cells commonly average the immune responses, neglecting the precise pathogen localization. to overcome this limitation, we dissected the transcriptional immune response to shigella flexneri across different infection stages in bulk and single cells. this identified six distinct transcriptional profiles characterizing the dynamic, multilayered host respo ... | 2015 | 26123804 |
| hfq regulates acid tolerance and virulence by responding to acid stress in shigella flexneri. | shigella flexneri is an important etiological agent of bacillary dysentery in developing countries. the hfq protein is thought to play a major regulatory role in various cellular processes in this organism. however, the roles of hfq in stress tolerance and virulence in s. flexneri in response to environmental stress have not been fully studied. in this study, hfq was highly expressed when s. flexneri was exposed to low ph. growth retardation was observed in the hfq deletion mutant at ph values r ... | 2015 | 26117597 |
| clonal dissemination of a single shigella sonnei strain among iranian children during fall 2012 in tehran, i.r. iran. | shigella species are a common cause of bacterial diarrhea worldwide and the disease is characterized by seasonality. shigella has been encountered by widespread resistance to commonly used antibiotics which is a serious concern. the aim of this study was to analyze the epidemiological relatedness of shigella strains isolated from children during one year period by pfge method and to investigate antimicrobial resistance determinants and cassettes among shigella species. the occurrence of shigella ... | 2015 | 26117443 |
| bioimage analysis of shigella infection reveals targeting of colonic crypts. | few studies within the pathogenic field have used advanced imaging and analytical tools to quantitatively measure pathogenicity in vivo. in this work, we present a novel approach for the investigation of host-pathogen processes based on medium-throughput 3d fluorescence imaging. the guinea pig model for shigella flexneri invasion of the colonic mucosa was used to monitor the infectious process over time with gfp-expressing s. flexneri. a precise quantitative imaging protocol was devised to follo ... | 2015 | 26056271 |
| draft genomes of shigella strains used by the stopenterics consortium. | despite a significant global burden of disease, there is still no vaccine against shigellosis widely available. one aim of the european union funded stopenterics consortium is to develop vaccine candidates against shigella. given the importance of translational vaccine coverage, here we aimed to characterise the shigella strains being used by the consortium by whole genome sequencing, and report on the stability of strains cultured in different laboratories or through serial passage. | 2015 | 26042182 |
| antimicrobial resistance of shigella flexneri serotype 1b isolates in china. | shigella flexneri serotype 1b is among the most prominent serotypes in developing countries, followed by serotype 2a. however, only limited data is available on the global phenotypic and genotypic characteristics of s. flexneri 1b. in the present study, 40 s. flexneri 1b isolates from different regions of china were confirmed by serotyping and biochemical characterization. antimicrobial susceptibility testing showed that 85% of these isolates were multidrug-resistant strains and antibiotic susce ... | 2015 | 26039698 |
| shigella flexneri cell-to-cell spread, and growth and inflammation in mice, is limited by the outer membrane protease icsp. | the shigella flexneri autotransporter protein icsa is essential for intra- and intercellular spread, and icsa mutants are attenuated in several models. however, the pathogenic significance of the outer membrane protease icsp, which orchestrates the polar distribution of icsa on the bacterial surface, remains unclear. to further examine this point, we constructed icsp mutants in the two most commonly studied s. flexneri strains and evaluated their in vitro and in vivo performance relative to wild ... | 2015 | 26025071 |
| draft genome sequence of 24570, the type strain of shigella flexneri. | shigella flexneri is a diarrheal pathogen that causes a large disease burden worldwide. we sequenced the genome of the publicly available type strain (s. flexneri 2a strain 24570) of this bacterial species to increase its utility as a reference. we present genome assembly results and comparisons with other reference strains. | 2015 | 26021915 |
| escape of actively secreting shigella flexneri from atg8/lc3-positive vacuoles formed during cell-to-cell spread is facilitated by icsb and vira. | the enteropathogenic bacterium shigella flexneri uses a type 3 secretion apparatus (t3sa) to transfer proteins dubbed translocators and effectors inside host cells, inducing bacterial uptake and subsequent lysis of the entry vacuole. once in the cytoplasm, the outer membrane protein icsa induces actin polymerization, enabling cytoplasmic movement and cell-to-cell spread of bacteria. during this infectious process, s. flexneri is targeted by atg8/lc3. the effector icsb was proposed to inhibit lc3 ... | 2015 | 26015503 |
| prevalence and antimicrobial resistance of shigella flexneri serotype 2 variant in china. | shigella flexneri serotype 2 variant (ii:3,4,7,8) was isolated in 2008 and first reported in china in 2013. in the present study, epidemiological surveillance from 2003 to 2013 in china suggested that this serotype first appeared in guangxi in 2003; it then emerged in shanghai and xinjiang in 2004 and in henan in 2008. of the 1813 s. flexneri isolates, 58 s. flexneri serotype 2 variant strains were identified. serotype 2 variant has emerged as a prominent serotype in recent years, with 2a (32.6% ... | 2015 | 25999941 |
| effect of combination therapy between thyme oil and ciprofloxacin on ulcer-forming shigella flexneri. | shigella flexneri is a gram-negative bacteria that has the ability to invade the epithelium of the colon and cause colon ulcers. | 2015 | 25989168 |
| shigella flexneri: a cause of significant morbidity and associated with sexually transmitted infections in men who have sex with men. | 2015 | 25970314 | |
| intensified shigellosis epidemic associated with sexual transmission in men who have sex with men--shigella flexneri and s. sonnei in england, 2004 to end of february 2015. | surveillance data suggest an intensification of the shigellosis epidemic associated with sexual transmissionin men who have sex with men (msm) in england with separate introductions into the population. in 2014, sexual transmission between msm might have accounted for 97%, 89%, and 43% of non-travel associated shigella flexneri 3a and s. flexneri 2a, ands. sonnei diagnoses. clinicians should sensitively ascertain sexual history for men with enteric infections to facilitate prompt diagnosis and a ... | 2015 | 25953129 |
| intercontinental dissemination of azithromycin-resistant shigellosis through sexual transmission: a cross-sectional study. | shigellosis is an acute, severe bacterial colitis that, in high-income countries, is typically associated with travel to high-risk regions (africa, asia, and latin america). since the 1970s, shigellosis has also been reported as a sexually transmitted infection in men who have sex with men (msm), in whom transmission is an important component of shigellosis epidemiology in high-income nations. we aimed to use sophisticated subtyping and international sampling to determine factors driving shigell ... | 2015 | 25936611 |
| shigella flexneri serotype 3a: the rise of a superbug. | 2015 | 25936610 | |
| sex, drugs and smart phone applications: findings from semistructured interviews with men who have sex with men diagnosed with shigella flexneri 3a in england and wales. | to inform control strategies undertaken as part of an outbreak of shigella flexneri 3a among men who have sex with men (msm). | 2015 | 25921020 |
| o-antigen modifications providing antigenic diversity of shigella flexneri and underlying genetic mechanisms. | o-antigens (o-specific polysaccharides) of shigella flexneri, a primary cause of shigellosis, are distinguished by a wide diversity of chemical modifications following the oligosaccharide o-unit assembly. the present review is devoted to structural, serological, and genetic aspects of these modifications, including o-acetylation and phosphorylation with phosphoethanolamine that have been identified recently. the modifications confer the host with specific immunodeterminants (o-factors or o-antig ... | 2015 | 26542003 |
| the passenger-associated transport repeat promotes virulence factor secretion efficiency and delineates a distinct autotransporter subtype. | autotransporters are a superfamily of virulence factors secreted by gram negative bacteria. they are comprised of an n-terminal passenger domain that is translocated across the outer membrane and a c-terminal domain that inserts into the outer membrane forming a β-barrel anchor. it is still poorly understood how the passenger is efficiently translocated in the absence of external energy inputs. several mechanisms have been proposed in solution of this problem, yet due to the vast diversity of si ... | 2015 | 25869731 |
| enhanced resistance to fluoroquinolones in laboratory-grown mutants & clinical isolates of shigella due to synergism between efflux pump expression & mutations in quinolone resistance determining region. | there is a worldwide emergence of fluoroquinolone resistance in shigella species. to understand the molecular mechanisms associated with fluoroquinolone resistance, naturally occurring fluoroquinolone-resistant strains and laboratory-induced spontaneous mutants of shigella spp. were used and the relative contributions of acrab-tolc efflux pumps, gyrase and topoisomerase target gene mutations towards fluoroquinolone resistance were determined. | 2015 | 25857499 |
| myosin-x and disease. | myosin-x (myo10) is a motor protein best known for its role in filopodia formation. new research implicates myo10 in a number of disease states including cancer metastasis and pathogen infection. this review focuses on these developments with emphasis on the emerging roles of myo10 in formation of cancer cell protrusions and metastasis. a number of aggressive cancers show high levels of myo10 expression and knockdown of myo10 has been shown to dramatically limit cancer cell motility in 2d and 3d ... | 2015 | 25819274 |
| key residues of s. flexneri ompa mediate infection by bacteriophage sf6. | many viruses, including bacteriophage, have the inherent ability to utilize several types of proteinaceous receptors as an attachment mechanism to infect cells, yet the molecular mechanisms that drive receptor binding have not been elucidated. using bacteriophage sf6 and its host, shigella flexneri, we investigated how sf6 utilizes outer membrane protein a (ompa) for infection. specifically, we identified that surface loops of ompa mediate shigella infection. we further characterized which resid ... | 2015 | 25816773 |
| myristoylome profiling reveals a concerted mechanism of arf gtpase deacylation by the bacterial protease ipaj. | n-myristoylation is an essential fatty acid modification that governs the localization and activity of cell signaling enzymes, architectural proteins, and immune regulatory factors. despite its importance in health and disease, there are currently no methods for reversing protein myristoylation in vivo. recently, the shigella flexneri protease ipaj was found to cleave myristoylated glycine of eukaryotic proteins, yet the discriminatory mechanisms of substrate selection required for targeted demy ... | 2015 | 25773595 |
| shigella flexneri regulation of arf6 activation during bacterial entry via an ipgd-mediated positive feedback loop. | entry into cells is critical for virulence of the human bacterial pathogens shigella spp. shigella spp. induce membrane ruffle formation and macropinocytic uptake, but the events instigating this process are incompletely understood. the host small gtpase adp-ribosylation factor 6 (arf6) functions in membrane trafficking at the plasma membrane and activates membrane ruffle formation. we demonstrate that arf6 is required for efficient shigella flexneri entry, is activated by s. flexneri dependent ... | 2015 | 25736891 |
| aa479 antiserum: new reagent for the serotype characterization of atypical variants of shigella flexneri. | shigella flexneri is divided into 13 serotypes based on the combination of antigenic determinants present in the o-antigen. a new o-antigen modification with phosphoethanolamine has been identified. the presence of this antigenic determinant (called e1037) is recognized by monoclonal antibody masf iv-1. given the increasing incidence of these new variants and the difficulty in supplying the monoclonal antibody to our country, we produced a polyclonal antiserum (aa479) through immunization with a ... | 2015 | 25735215 |
| shift in serotype distribution of shigella species in china, 2003-2013. | we identified 2912 shigella isolates from diarrhoeal patients in china during 2003-2013. the most common species was shigella flexneri (55.3%), followed by shigella sonnei (44.1%); however, s. sonnei is becoming increasingly prevalent. among the s. flexneri isolates, serotypes 2a and x variant (-:7,8, e1037) were the two most prevalent serotypes, and serologically atypical isolates were also commonly identified. overall, s. sonnei, s. flexneri 2a and s. flexneri x variant (-:7,8, e1037) accounte ... | 2015 | 25658535 |
| shigella flexneri serotype 1 infections in men who have sex with men in vancouver, canada. | outbreaks of shigellosis have been documented in men who have sex with men (msm), associated with interpersonal transmission and underlying hiv infection. we observed a rise in shigella flexneri isolates identified in a downtown tertiary-care hospital laboratory located within the city centre community health area (cha-1) of vancouver, canada. the objectives of this study were to evaluate clinical outcomes of shigellosis cases among msm admitted to hospital and to evaluate trends in shigella cas ... | 2015 | 25656740 |
| the shigella flexneri ospb effector: an early immunomodulator. | through the action of the type three secretion system (t3ss) shigella flexneri delivers several effectors into host cells to promote cellular invasion, multiplication and to exploit host-cell signaling pathways to modulate the host innate immune response. although much progress has been made in the understanding of many type iii effectors, the molecular and cellular mechanism of the ospb effector is still poorly characterized. in this study we present new evidence that better elucidates the role ... | 2015 | 25434600 |
| update on molecular epidemiology of shigella infection. | shigella spp. are important etiologic agents of diarrhea worldwide. this review summarizes the recent findings on the epidemiology, diagnosis, virulence genes, and pathobiology of shigella infection. | 2015 | 25394237 |
| mutational analysis of the major periplasmic loops of shigella flexneri wzy: identification of the residues affecting o antigen modal chain length control, and wzz-dependent polymerization activity. | the o antigen (oag) component of lps is a major shigella flexneri virulence determinant. oag is polymerized by wzysf, and its modal chain length is determined by wzzsf and wzzphs2. site-directed mutagenesis was performed on wzysf in pwaldo-wzysf-tev-gfp to alter arg residues in wzysf's two large periplasmic loops (pls) (pl3 and pl5). analysis of the lps profiles conferred by mutated wzysf proteins in the wzysf deficient (δwzy) strain identified residues that affect wzysf activity. the importance ... | 2015 | 25627441 |
| specific 13c labeling of leucine, valine and isoleucine methyl groups for unambiguous detection of long-range restraints in protein solid-state nmr studies. | here we present an isotopic labeling strategy to easily obtain unambiguous long-range distance restraints in protein solid-state nmr studies. the method is based on the inclusion of two biosynthetic precursors in the bacterial growth medium, α-ketoisovalerate and α-ketobutyrate, leading to the production of leucine, valine and isoleucine residues that are exclusively (13)c labeled on methyl groups. the resulting spectral simplification facilitates the collection of distance restraints, the verif ... | 2015 | 25625825 |
| genetic characterization of shigella flexneri isolates in guizhou province, china. | shigella flexneri is one of the major etiologic causes of shigellosis in guizhou province, china. however, the genetic characteristics of circulating isolates are unknown. phenotypic and molecular profiles of 60 s. flexneri isolates recovered in guizhou between 1972 to 1982 and 2008 to 2010 were determined. nine serotypes (1a, 2a, 3a, 1b, 2b, x, y, 4av and yv) were identified. multi-locus sequence typing differentiated the isolates into 20 sequence types (sts); 18 were novel. four sts, st 129, s ... | 2015 | 25617838 |
| overexpression, purification, crystallization and preliminary x-ray crystallographic analysis of sf173 from shigella flexneri. | shigella flexneri is a gram-negative, anaerobic bacterium in the genus shigella that can cause diarrhoea in humans. sf173, a hypothetical protein from s. flexneri 5a strain m90t, has been cloned, overexpressed, purified and crystallized as a part of laboratory-scale structural genomics project. the sf173 protein was crystallized using the sitting-drop vapour-diffusion method in the presence of 0.8 m succinic acid ph 7.0 at 293 k. preliminary x-ray diffraction analysis revealed that the crystal d ... | 2015 | 25615969 |
| tom1 is a pi5p effector involved in the regulation of endosomal maturation. | phosphoinositides represent a major class of lipids specifically involved in the organization of signaling cascades, maintenance of the identity of organelles and regulation of multiple intracellular trafficking steps. we previously reported that phosphatidylinositol 5-monophosphate (pi5p), produced by the shigella flexneri phosphatase ipgd, is implicated in the endosomal sorting of the epidermal growth factor receptor (egfr). here, we show that the adaptor protein tom1 is a new direct binding p ... | 2015 | 25588840 |
| comparison of resistance to third-generation cephalosporins in shigella between europe-america and asia-africa from 1998 to 2012. | we conducted a systematic review to compare resistance to third-generation cephalosporins (tgcs) in shigella strains between europe-america and asia-africa from 1998 to 2012 based on a literature search of computerized databases. in asia-africa, the prevalence of resistance of total and different subtypes to ceftriaxone, cefotaxime and ceftazidime increased markedly, with a total prevalence of resistance up to 14·2% [95% confidence interval (ci) 3·9-29·4], 22·6% (95% ci 4·8-48·6) and 6·2% (95% c ... | 2015 | 25553947 |
| outbreak of locally acquired azithromycin-resistant shigella flexneri infection in men who have sex with men. | 2015 | 25474524 | |
| detection and analysis of crisprs of shigella. | the recently discovered crisprs (clustered regularly interspaced short palindromic repeats) and cas (crispr-associated) proteins are a novel genetic barrier that limits horizontal gene transfer in prokaryotes and the crispr loci provide a historical view of the exposure of prokaryotes to a variety of foreign genetic elements. the aim of study was to investigate the occurrence and distribution of the crisprs in shigella. a collection of 61 strains of shigella were screened for the existence of cr ... | 2015 | 25199561 |
| travel-related shigellosis in quebec, canada: an analysis of risk factors. | travel-related shigellosis is not well documented in canada although it is frequently acquired abroad and can cause severe disease. | 2015 | 24889090 |
| transcriptional adaptation of shigella flexneri during adherence to epithelial cells. | shigella adhesion to host cells is a transitional stage from an extracellular to an intracellular environment. however, the dynamic adaptations of shigella during adhesion are poorly understood. to address this, we performed the first transcriptome analysis of shigella flexneri 2457t during adhesion. a total of 1,757 genes were differentially regulated (>twofold). the majority of plasmid-borne ipa-mxi-spa locus genes were downregulated, indicating these virulence genes were strictly regulated af ... | 2015 | 25291620 |
| hypoxic stress, hepatocytes and caco-2 viability and susceptibility to shigella flexneri invasion. | inflammation due to shigella flexneri can cause damage to the colonic mucosa and cell death by necrosis and apoptosis. this bacteria can reach the bloodstream in this way, and the liver through portal veins. hypoxia is a condition present in many human diseases, and it may induce bacterial translocation from intestinal lumen. we studied the ability of s. flexneri to invade rat hepatocytes and caco-2 cells both in normoxic and hypoxic microenvironments, as well as morphological and physiological ... | 2015 | 24037289 |
| shigella flexneri enteritis in risk-taking hiv-infected msm. | 2014 | 24055803 | |
| outer membrane protein a (ompa) of shigella flexneri 2a induces tlr2-mediated activation of b cells: involvement of protein tyrosine kinase, erk and nf-κb. | b cells are critically important in combating bacterial infections and their differentiation into plasma cells and memory cells aids bacterial clearance and long-lasting immunity conferred by essentially all vaccines. outer membrane protein a (ompa) of shigella flexneri 2a has been demonstrated to induce the production of igg and iga in vivo following immunization of mice through intranasal route, but the direct involvement of b cells in ompa-mediated immune regulation was not determined. conseq ... | 2014 | 25286253 |
| high-resolution structure of the shigella type-iii secretion needle by solid-state nmr and cryo-electron microscopy. | we introduce a general hybrid approach for determining the structures of supramolecular assemblies. cryo-electron microscopy (cryo-em) data define the overall envelope of the assembly and rigid-body orientation of the subunits while solid-state nuclear magnetic resonance (ssnmr) chemical shifts and distance constraints define the local secondary structure, protein fold and inter-subunit interactions. finally, rosetta structure calculations provide a general framework to integrate the different s ... | 2014 | 25264107 |
| [shigella flexneri bacteremia, one adult case and review of the literature]. | 2014 | 25229381 | |
| use of shigella flexneri to study autophagy-cytoskeleton interactions. | shigella flexneri is an intracellular pathogen that can escape from phagosomes to reach the cytosol, and polymerize the host actin cytoskeleton to promote its motility and dissemination. new work has shown that proteins involved in actin-based motility are also linked to autophagy, an intracellular degradation process crucial for cell autonomous immunity. strikingly, host cells may prevent actin-based motility of s. flexneri by compartmentalizing bacteria inside 'septin cages' and targeting them ... | 2014 | 25226510 |
| an optofluidic imaging system to measure the biophysical signature of single waterborne bacteria. | in this paper, for the first time, an on-chip optofluidic imaging system is innovated to measure the biophysical signatures of single waterborne bacteria, including both their refractive indices and morphologies (size and shape), based on immersion refractometry. the key features of the proposed optofluidic imaging platform include (1) multiple sites for single-bacterium trapping, which enable parallel measurements to achieve higher throughput, and (2) a chaotic micromixer, which enables efficie ... | 2014 | 25205636 |
| spa13 of shigella flexneri has a dual role: chaperone escort and export gate-activator switch of the type iii secretion system. | the type iii secretion apparatus (t3sa) is used by numerous gram-negative pathogens to inject virulence factors into eukaryotic cells. the shigella flexneri t3sa spans the bacterial envelope and its assembly requires the products of ~20 mxi and spa genes. despite progress made in understanding how the t3sa is assembled, the role of several predicted soluble components, such as spa13, remains elusive. here, we show that the secretion defect of the spa13 mutant is associated with lack of t3sa asse ... | 2014 | 24126350 |
| shigella flexneri inhibits intestinal inflammation by modulation of host sphingosine-1-phosphate in mice. | infection with invasive shigella species results in intestinal inflammation in humans but no symptoms in adult mice. to investigate why adult mice are resistant to invasive shigellae, 6~8-week-old mice were infected orally with s. flexneri 5a. shigellae successfully colonized the small and large intestines. mild cell death was seen but no inflammation. the infected bacteria were cleared 24 hours later. microarray analysis of infected intestinal tissue showed that several genes that are involved ... | 2014 | 24851099 |
| non-stoichiometric o-acetylation of shigella flexneri 2a o-specific polysaccharide: synthesis and antigenicity. | synthetic functional mimics of the o-antigen from shigella flexneri 2a are seen as promising vaccine components against endemic shigellosis. herein, the influence of the polysaccharide non-stoichiometric di-o-acetylation on antigenicity is addressed for the first time. three decasaccharides, representing relevant internal mono- and di-o-acetylation profiles of the o-antigen, were synthesized from a pivotal protected decasaccharide designed to tailor late stage site-selective o-acetylation. the l ... | 2014 | 24836582 |
| genetic characterization of shigella spp. isolated from diarrhoeal and asymptomatic children. | phenotypic and genetic characteristics of shigella spp. isolated from diarrhoeal and asymptomatic children aged up to 5 years were analysed in this study. in total, 91 and 17 isolates were identified from diarrhoeal (case) and asymptomatic (control) children, respectively. all the isolates were tested for antimicrobial resistance, the presence of integrons, plasmid-mediated quinolone resistance (pmqr), virulence-associated genes and shigella pathogenicity island (sh-pai). the majority of the shi ... | 2014 | 24790083 |
| dynamin-related protein drp1 and mitochondria are important for shigella flexneri infection. | shigella infection in epithelial cells induces cell death which is accompanied by mitochondrial dysfunction. in this study the role of the mitochondrial fission protein, drp1 during shigella infection in hela cells was examined. significant lactate dehydrogenase (ldh) release was detected in the culture supernatant when hela cells were infected with shigella at a high multiplicity of infection. drp1 inhibition with mdivi-1 and sirna knockdown significantly reduced ldh release. hela cell death wa ... | 2014 | 24755420 |
| role of intracellular carbon metabolism pathways in shigella flexneri virulence. | shigella flexneri, which replicates in the cytoplasm of intestinal epithelial cells, can use the embden-meyerhof-parnas, entner-doudoroff, or pentose phosphate pathway for glycolytic carbon metabolism. to determine which of these pathways is used by intracellular s. flexneri, mutants were constructed and tested in a plaque assay for the ability to invade, replicate intracellularly, and spread to adjacent epithelial cells. mutants blocked in the embden-meyerhof-parnas pathway (pfkab and pykaf mut ... | 2014 | 24733092 |
| icsa is a shigella flexneri adhesin regulated by the type iii secretion system and required for pathogenesis. | following contact with the epithelium, the enteric intracellular bacterial pathogen shigella flexneri invades epithelial cells and escapes intracellular phagosomal destruction using its type iii secretion system (t3ss). the bacterium replicates within the host cell cytosol and spreads between cells using actin-based motility, which is mediated by the virulence factor icsa (virg). whereas s. flexneri invasion is well characterized, adhesion mechanisms of the bacterium remain elusive. we found tha ... | 2014 | 24721572 |
| draft genome sequences of the type strains of shigella flexneri held at public health england: comparison of classical phenotypic and novel molecular assays with whole genome sequence. | public health england (phe) holds a collection of shigella flexneri type strains isolated between 1949 and 1972 representing 15 established serotypes and one provisional type, e1037. in this study, the genomes of all 16 phe type strains were sequenced using the illumina hiseq platform. the relationship between core genome phylogeny and serotype was examined. | 2014 | 24684748 |
| ompa and ompc are critical host factors for bacteriophage sf6 entry in shigella. | despite being essential for successful infection, the molecular cues involved in host recognition and genome transfer of viruses are not completely understood. bacterial outer membrane proteins a and c co-purify in lipid vesicles with bacteriophage sf6, implicating both outer membrane proteins as potential host receptors. we determined that outer membrane proteins a and c mediate sf6 infection by dramatically increasing its rate and efficiency. we performed a combination of in vivo studies with ... | 2014 | 24673644 |
| serological identification and prevalence of a novel o-antigen epitope linked to 3- and 4-o-acetylated rhamnose iii of lipopolysaccharide in shigella flexneri. | shigella flexneri is the major cause of shigellosis in developing countries. all serotypes except for serotype 6 share an o-antigen backbone composed of a → 2)-α-l-rhap(iii)-(1 → 2)-α-l-rhap(ii)-(1 → 3)-α-l-rhap(i)-(1 → 3)-β-d-glcpnac-(1 → tetrasaccharide repeat. it can be modified by the addition of a glucosyl group to one or more sugar residues and/or an o-acetyl group to rha(i) and/or a phosphoethanolamine to rha(ii) and/or rha(iii). these modifications give rise to type i-, ic-, ii-, iv-, an ... | 2014 | 24671799 |
| new insights into the crosstalk between shigella and t lymphocytes. | subversion of host immune responses is the key infection strategy employed by most, if not all, human pathogens. modulation of the host innate response by pathogens has been vastly documented. yet, especially for bacterial infections, it was only recently that cells of the adaptive immune response were recognized as targets of bacterial weapons such as the type iii secretion system (t3ss) and its effector proteins. in this review, we focus on the recent advances made in the understanding of how ... | 2014 | 24613405 |
| conformational diversity of o-antigen polysaccharides of the gram-negative bacterium shigella flexneri serotype y. | o-antigen polysaccharides constitute the outer protective layer of most gram-negative bacteria, important for the bacterium's survival and adaption within its host. although important for many functions, the three-dimensional structure of the dense polysaccharide coat remains to be elucidated. in this study, we present a systematic numerical investigation of o-antigen polysaccharide chains of shigella flexneri serotype y composed of one up to four tetrasaccharide repeat units. to bridge the gap ... | 2014 | 24559142 |
| potential novel antibiotics from hts targeting the virulence-regulating transcription factor, virf, from shigella flexneri. | virf is an arac-type transcriptional regulator responsible for activating the transcription of virulence genes required for the intracellular invasion and cell-to-cell spread of shigella flexneri. gene disruption studies have validated virf as a potential target for an anti-virulence therapy to treat shigellosis by determining that virf is necessary for virulence, but not required for bacterial viability. using a bacteria-based, β-galactosidase reporter assay we completed a high-throughput scree ... | 2014 | 24549153 |
| a fluorescent reporter reveals on/off regulation of the shigella type iii secretion apparatus during entry and cell-to-cell spread. | numerous pathogenic gram-negative bacteria use a type three secretion apparatus (t3sa) to translocate effector proteins into host cells. detecting and monitoring the t3sa of intracellular bacteria within intact host cells has been challenging. taking advantage of the tight coupling between t3s effector-gene transcription and t3sa activity in shigella flexneri, together with a fast-maturing green fluorescent protein, we developed reporters to monitor t3sa activity in real time. these reporters re ... | 2014 | 24528864 |
| oral administration of live shigella vaccine candidates in rhesus monkeys show no evidence of competition for colonization and immunogenicity between different serotypes. | live oral monovalent shigella flexneri 2a vaccine candidates as well as bivalent formulations with shigella sonnei were evaluated in a rhesus monkey model for colonization and immunogenicity. freshly harvested suspensions of s. flexneri 2a vaccine candidates wrsf2g12 and wrsf2g15 as well as s. sonnei vaccine candidate wrss3 were nasogastrically administered to groups of rhesus monkeys, macaca mulatta, either in a monovalent form or when combined with each other. the animals were monitored daily ... | 2014 | 24522159 |
| shigellemia in a post renal transplant patient: a case report and literature review. | shigellemia is a complication of shigellosis that occurs generally in malnourished children. in adults, shigellemia is usually seen in immunocompromised individuals. here we report the first case of shigellemia in a renal transplant patient from india. the patient had history of diarrhea, which was treated symptomatically. subsequently, the patient developed high-grade fever and blood culture was positive for shigella flexneri. recovery was uneventful after the initiation of antimicrobial therap ... | 2014 | 24518636 |
| identification of an o-acyltransferase gene (oacb) that mediates 3- and 4-o-acetylation of rhamnose iii in shigella flexneri o antigens. | o antigen (o polysaccharide) is an important and highly variable cell component present on the surface of cells which defines the serospecificity of gram-negative bacteria. most o antigens of shigella flexneri, a cause of shigellosis, share a backbone composed of →2)-α-l-rhap(iii)-(1→2)-α-l-rhap(ii)-(1→3)-α-l-rhap(i)-(1→3)-β-d-glcpnac-(1→ repeats, which can be modified by adding various substituents, giving rise to 19 serotypes. the known modifications include glucosylation on various sugar resi ... | 2014 | 24509314 |
| case of shigella flexneri infection with treatment failure due to azithromycin resistance in an hiv-positive patient. | 2014 | 24488332 | |
| the vps/vacj abc transporter is required for intercellular spread of shigella flexneri. | the vps/vacj abc transporter system is proposed to function in maintaining the lipid asymmetry of the outer membrane. mutations in vps or vacj in shigella flexneri resulted in increased sensitivity to lysis by the detergent sodium dodecyl sulfate (sds), and the vpsc mutant showed minor differences in its phospholipid profile compared to the wild type. vpsc mutants were unable to form plaques in cultured epithelial cells, but this was not due to a failure to invade, to replicate intracellularly, ... | 2014 | 24478081 |
| a substrate-fusion protein is trapped inside the type iii secretion system channel in shigella flexneri. | the type iii secretion system (t3ss) is a macromolecular complex used by gram-negative bacteria to secrete effector proteins from the cytoplasm across the bacterial envelope in a single step. for many pathogens, the t3ss is an essential virulence factor that enables the bacteria to interact with and manipulate their respective host. a characteristic structural feature of the t3ss is the needle complex (nc). the nc resembles a syringe with a basal body spanning both bacterial membranes and a long ... | 2014 | 24453973 |
| genomic portrait of the evolution and epidemic spread of a recently emerged multidrug-resistant shigella flexneri clone in china. | shigella flexneri is the major cause of shigellosis in developing countries. a new s. flexneri serotype, xv, appeared in 2000 and replaced serotype 2a as the most prevalent serotype in china. serotype xv is a variant of serotype x, with phosphoethanolamine modification of its o antigen mediated by a plasmid that contained the opt gene. serotype xv isolates belong to sequence type 91 (st91). in this study, whole-genome sequencing of 59 s. flexneri isolates of 14 serotypes (serotypes 1 to 4, y, yv ... | 2014 | 24452172 |
| plasmid-mediated sulfamethoxazole resistance encoded by the sul2 gene in the multidrug-resistant shigella flexneri 2a isolated from patients with acute diarrhea in dhaka, bangladesh. | in this study, mechanisms of plasmid-mediated sulfamethoxazole resistances in the clinical strains of multi-drug resistant (mdr) shigella flexneri 2a were elucidated for the first time in bangladesh. from 2006 to 2011, a total of 200 s. flexneri 2a strains were randomly selected from the stock of the enteric and food microbiology laboratory of icddr,b. antimicrobial susceptibility of the strains showed 73%, 98%, 93%, 58%, 98%, 64% and 4% resistance to trimethoprim-sulfamethoxazole, nalidixic aci ... | 2014 | 24416393 |
| effect of wild-type shigella species and attenuated shigella vaccine candidates on small intestinal barrier function, antigen trafficking, and cytokine release. | bacterial dysentery due to shigella species is a major cause of morbidity and mortality worldwide. the pathogenesis of shigella is based on the bacteria's ability to invade and replicate within the colonic epithelium, resulting in severe intestinal inflammatory response and epithelial destruction. although the mechanisms of pathogenesis of shigella in the colon have been extensively studied, little is known on the effect of wild-type shigella on the small intestine and the role of the host respo ... | 2014 | 24416363 |