Publications

TitleAbstractYear
Filter
PMID
Filter
vaccination against bacterial gut infections.recent developments in the field of vaccination against gut-borne bacterial illness are reviewed, including the major pathogens such as salmonella, shigella, cholera and escherichia coli. the approaches covered range from immunization with killed and live attenuated organisms to genetically detoxified toxin molecules and dna vaccination and transgenic foods. both homologous and heterologous responses to various organisms and vector technologies are discussed in murine, bovine and human models, a ...199817033426
host responses to secreted shigella virulence factors.shigella and related enteropathogens deliver effector molecules into the cytoplasm of epithelial cells and macrophages via a type iii secretion system. epithelial cells respond to contact with shigella by rearranging the cytoskeleton, which leads to uptake of the bacterium. apart from several cytoskeletal proteins, this process involves the recruitment and activation of kinases, and the small gtpase rho. macrophages infected with shigella undergo apoptosis and release mature il-1beta, a pro-infl ...199917035783
direct detection of bacterial faecal indicators in water samples using pcr.the presence of enteric pathogens in water resources represents a serious risk for public health. therefore, their precise detection, and especially detection of e. coli, which is obviously regarded as the main indicator of faecal contamination of water, is an essential step in ensuring bacterial safety of water. numerous pcr protocols for detection of e. coli have been published to date. they are usually based on amplification of regions derived from lacz (beta-d-galactosidase) and uida (beta-d ...200617037144
[rapid detection of pseudomonas aeruginosa by the fluorescence quantitative pcr assay targeting 16s rdna].the 16s rdna specific primers were designed for rapid detection of pseudomonas aeruginosa (pa) by the fluorescence quantitative pcr (fq-pcr) assay, based upon multiple sequence alignment and phylogenetic tree analysis of the 16s rdnas of over 20 bacteria. after extraction of pa genomic dna, the target 16s rdna fragment was amplified by pcr with specific primers, and used to construct recombinant pmdt-pfr plasmid, the dilution gradients of which were subjected to the standard quantitation curve i ...200617037203
wavelet analysis of dna walks.a wavelet transform of the dna "walk" constructed from a genomic sequence offers a direct visualization of short and long-range patterns in nucleotide sequences. we study sequences that encode diverse biological functions, taken from a variety of genomes. pattern irregularities in the transform are frequently associated with sequences of biological interest. exonic regions, for example, visualize differently under wavelet analysis than introns, and ribosomal rna regions display distinct universa ...200617037959
a field study of the microbiological quality of fresh produce of domestic and mexican origin.produce is responsible for an increasingly larger proportion of foodborne disease outbreaks. in particular, the globalization of the food supply may introduce new food safety risks and allow widespread distribution of contaminated food, particularly produce. the objectives of this study were to: (i) compare the overall quality of domestic and mexican produce throughout the packing process; (ii) examine changes in microbiological quality of both domestic and mexican produce at each stage of produ ...200617045687
detection of genogroup i and ii human picobirnaviruses showing small genomic rna profile causing acute watery diarrhoea among children in kolkata, india.picobirnaviruses (pbvs) with bisegmented small rna genome profile (1.75 and 1.55kbp for segment 1 and 2, respectively) were detected from 1999 to 2003 in faecal specimens of acute watery diarrhoea cases, largely children (n=20) and an adult in kolkata, india. varying degrees of dehydration necessitated their visit to hospital for further treatment and management of acute watery diarrhoea. pbv was associated with rotavirus (n=3) or astrovirus (n=3) and with both in one case. no co-infection with ...200717049316
13c nmr spectroscopy of core heme carbons as a simple tool to elucidate the coordination state of ferric high-spin heme proteins.evidence is presented demonstrating that the magnitudes of the 13c chemical shifts originating from heme meso carbons provide a straightforward diagnostic tool to elucidate the coordination state of high-spin heme proteins and enzymes. pentacoordinate high-spin heme centers exhibit 13c meso shifts centered at approximately 250 ppm, whereas their hexacoordinate counterparts exhibit 13c shifts centered at approximately -80 ppm. the relatively small spectral window (400 to -100 ppm) covering the me ...200617054345
distribution of shigella enterotoxin genes and secreted autotransporter toxin gene among diverse species and serotypes of shigella isolated from andaman islands, india.we studied the prevalence and distribution of the newly described genes for shigella enterotoxins (shet1 and shet2, encoded by set and sen genes) and secreted auto-transporter toxin (encoded by sat gene) in clinical isolates from the andaman islands, india. a total of 153 shigella isolates obtained from hospitalized patients during 1994-2004 were analysed. these isolates included all the four species of shigella (s. dyseteriae-29, s. flexneri-75, s. sonnei-38, s. boydii-5) that belonged to diver ...200617054749
the bacterial weaponry: lessons from shigella.shigella, a gram-negative bacterial species of the family enterobacteriaceae, causes bacillary dysentery in humans, an acute rectocolitis that reflects the capacity of the microorganism to disrupt, invade, and cause the inflammatory destruction of the intestinal epithelium. here, the pathogenesis of shigella infection is analyzed in the context of the disruption of the homeostatic balance that protects the gut against inflammation in the presence of its commensal flora. thus a unified view by wh ...200617057210
metalloantibiotics: synthesis, characterization and in-vitro antibacterial studies on cobalt (ii), copper (ii), nickel (ii) and zinc (ii) complexes with cloxacillin.the synthesis and characterization of cloxacillin (clox) complexes with divalent metal ions [co (ii), cu (ii), ni (ii) and zn (ii)] is described. the nature of bonding of the chelated cloxacillin and the structures of the metal complexes have been elucidated on the basis of their physical and spectroscopic data. in all the complexes, the cloxacillin acts as a uninegatively charged bidentate ligand with coordination involving the carboxylate-o and endocyclic-n of the beta-lactam ring. the new com ...200617059178
transcriptional slippage controls production of type iii secretion apparatus components in shigella flexneri.during transcription, series of approximately 9 as or ts can direct rna polymerase to incorporate into the mrna nucleotides not encoded by the dna, changing the reading frame downstream from the slippage site. we detected series of 9 or 10 as in spa13, spa33 and mxia encoding type iii secretion apparatus components. analysis of cdnas indicated that transcriptional slippage occurs in spa13, mxia and spa33. changes in the reading frame were confirmed by using plasmids carrying slippage sites in th ...200617059566
identification of essential loops and residues of glucosyltransferase v (gtrv) of shigella flexneri.lipopolysaccharide (lps), particularly the o-antigen component, is one of many virulence determinants necessary for shigella flexneri pathogenesis. o-antigen modification is mediated by glucosyltransferase (gtr) genes encoded by temperate serotype-converting bacteriophages. the gtrv and gtrx genes encode the gtrv and gtrx glucosyltransferases, respectively. these are integral membrane proteins, which catalyze the transfer of a glucosyl residue via an alpha1,3 linkage to rhamnose ii and rhamnose ...200617060158
ipaa targets beta1 integrins and rho to promote actin cytoskeleton rearrangements necessary for shigella entry.shigella invasion into the colonic epithelium involves many steps including the formation of large membrane protrusions by the epithelial cells that facilitate bacterial engulfment. ipaa, a shigella protein secreted into target cells upon cell contact induces a loss of actin stress fibers in cells and promotes the reorganization of actin at the site of entry. the mechanism for this is not known but is thought to involve recruitment of the focal adhesion protein vinculin to ipaa. here we have exa ...200617060328
effects of the bacteriocin psvp-10 produced by pseudomonas sp. on sensitive bacterial strains.the bacteriocin psvp-10 is a 2.6 kda peptide which was isolated and purified from pseudomonas sp. this bacteriocin possesses lethal activity over enterococcus faecalis, salmonella typhimurium and shigella flexneri. the experimental assays showed that the bacteriocin is able to be adsorbed by all cells of these bacterial species and also by their isolated cell walls. it was observed that the resistant mutants and their respective cell walls are unable to adsorb the bacteriocin. assays performed w ...200217061511
shigella flexneri strains produce bacteriocins active against members of the human microbial intestinal flora.the principal aim of this work was to detect the bacteriocinogenic capacity of s. flexneri strains on members of the human intestinal flora. a total of 49 bacteriocinogenic s. flexneri strains were isolated from individuals of both sexes and different ages. the bacteriocins were detected by means of the drop method using e. coli and b. fragilis as target strains. the serotypes of the s. flexneri were determined. the producer capacity of bacteriocins was analysed in 10 different colonies of the s ...200417061528
current aspects of shigella pathogenesis.bacillary dysentery (shigellosis) is a severe human disease caused by shigellae. in recent years, a large amount of information has been generated regarding the host, pathogen and environmental factors that impact the pathogenesis of shigellosis at the cellular and molecular level. this review summarizes what is currently known about shigella, detailing those factors that contribute to pathogenesis and examining the current progress in the development of a vaccine.200417061529
determination of the profile of fatty acids of 4 species of shigella spp by chromatography of gases.shigella boydii, shigella flexneri, shigella dysenteriae and shigella sonnei were identified using gas chromatography instead of the traditional techniques. their acid methyl esters profiles were determined using a gas chromatograph hewlett packard 5890a and a rsl-150 heliflex capillary column. a total of 192 samples were analyzed both reference strains (atcc 8700, indre b2188, b2194 and b2199) and environmental isolates. 12 fatty acids were included in the profiles from which 3-hydroxytetradeca ...200217063774
enterobacterial 38-kda outer membrane protein is an age-dependent molecular marker of innate immunity and immunoglobulin deficiency as results from its reactivity with igg and iga antibody.in earlier studies on an animal model we observed protective properties of outer membrane proteins (omps) of shigella, hafnia, and escherichia coli strains. in order to investigate human sera for reactivity with omps we subjected these proteins to immunoblotting with umbilical cord plasma and sera from children and adults. the igg and iga antibodies interacted primarily with a 38-kda protein, in similar way for several enterobacterial strains, but different for pseudomonas aeruginosa. this obser ...200617064276
prevalence and antimicrobial susceptibility patterns of shigella species in asmara, eritrea, northeast africa.diarrheal diseases are an important cause of morbidity and mortality in children in developing countries. of the bacterial causes of dysentery, shigella are the major enteropathogens with outbreak potential and common development of antimicrobial resistance. this study determined the prevalence and antimicrobial susceptibility patterns of different spp. of shigella in asmara, eritrea.200617066201
shigella sonnei outbreak among homosexual men, london. 200617073105
[amplified fragment length polymorphism genotyping of shigellae and comparison to pulsed-field gel electrophoresis and colicin typing].shigella is an etiological agent of communicable and food-borne disease worldwide, so it is important to develop typing for shigella in epidemiological studies. we compared amplified fragment length polymorphism (aflp), molecular epidemiological typing, to pulsed-field gel electrophoresis (pfge) and colicin typing in typeability, reproducibility, discriminatory power, ease of interpretation, and ease of use for 51 shigella isolates to determine aflp applicability to shigella. aflp showed less re ...200617073265
ce to monitor endotoxins by protein complexation.a new ce method for fast and efficient analysis of bacterial endotoxins (lipopolysaccharides) is described. it is based on the strong interaction between proteins and endotoxins. the uv absorption of the protein component in the complex is used for the detection. the electrophoretic mobility of the complex hemoglobin/endotoxin can be employed for qualitative analysis of the endotoxin. for instance, the structural differences between "smooth" and "rough" lipopolysaccharides from salmonella minnes ...200617075946
immunoproteome analysis of soluble and membrane proteins of shigella flexneri 2457t.to profile the immunogenic proteins of shigella flexneri (s. flexneri) expressed during human infection using a proteomic approach.200617075984
self-chaperoning of the type iii secretion system needle tip proteins ipad and bipd.bacteria expressing type iii secretion systems (t3ss) have been responsible for the deaths of millions worldwide, acting as key virulence elements in diseases ranging from plague to typhoid fever. the t3ss is composed of a basal body, which traverses both bacterial membranes, and an external needle through which effector proteins are secreted. we report multiple crystal structures of two proteins that sit at the tip of the needle and are essential for virulence: ipad from shigella flexneri and b ...200717077085
octaplex pcr and fluorescence-based capillary electrophoresis for identification of human diarrheagenic escherichia coli and shigella spp.a multiplex pcr assay, amplifying seven specific virulence genes and one internal control gene in a single reaction, was developed to identify the five main pathotypes of diarrheagenic escherichia coli and shigella spp. the virulence genes selected for each category were stx1, stx2, and eaea for enterohemorrhagic e. coli (ehec), eaea for enteropathogenic e. coli (epec), stib and lti for enterotoxigenic e. coli (etec), ipah for enteroinvasive e. coli (eiec) and shigella spp., and aggr for enteroa ...200717079041
structural studies of the o-antigenic polysaccharides from shigella dysenteriae type 3 and escherichia coli o124, a reinvestigation.the structures of the o-antigenic part of the lipopolysaccharides from shigella dysenteriae type 3 and escherichia coli o124 have been reinvestigated. (1)h and (13)c nmr spectroscopy in combination with selected 2d nmr techniques were used to determine the o-antigen pentasaccharide repeating units with the following structure: [see text]. from biosynthetic considerations this should also be the biological repeating unit. the structures of the repeating units also explain the previously observed ...200617081507
disinfection of sludge with high pathogenic content using silver and other compounds.a physicochemical sludge with high microbial content (10(2)-10(4) fpu/g ts bacteriophages, 10(6)-10(7) mpn/g ts faecal coliforms, 10(4) mpn/g ts salmonella spp., 10(4) mpn/g ts shigella spp., 10(3) mpn/g ts pseudomonas aeruginosa, 10(2) mpn/g ts vibrio cholerae, 10(2)-10(3) cysts/g ts giardia sp., 10(2)-10(4) oocyts/g ts cryptosporidium sp., 168-215 viable helminth ova/g ts) was disinfected using silver, silver-copper, and silver-copper plus a synergistic agent (sa). twenty milligrams ag/g ts in ...200617087384
o-acetylation in the o-specific polysaccharide isolated from shigella flexneri serotype 2a.shigella flexneri causes diarrheal diseases especially in infants and children in developing countries. modifications of the lipopolysaccharide (lps) molecule, like bacteriophage-mediated glucosylation and acetylation of the o-specific chain (o-sp), are important for the lps antigenicity and consequently for the immunogenicity of the polysaccharide-based vaccines against shigellosis. here, we report the degree of o-acetylation and the localisation of o-acetyl groups and side-chain glucose substi ...200717087926
shigella applies molecular mimicry to subvert vinculin and invade host cells.shigella flexneri, the causative agent of bacillary dysentery, injects invasin proteins through a type iii secretion apparatus upon contacting the host cell, which triggers pathogen internalization. the invasin ipaa is essential for s. flexneri pathogenesis and binds to the cytoskeletal protein vinculin to facilitate host cell entry. we report that ipaa harbors two vinculin-binding sites (vbss) within its c-terminal domain that bind to and activate vinculin in a mutually exclusive fashion. only ...200617088427
microbiology. bacterial bushwacking through a microtubule jungle. 200617095683
microtubule-severing activity of shigella is pivotal for intercellular spreading.some pathogenic bacteria actually invade the cytoplasm of their target host cells. invasive bacteria acquire the propulsive force to move by recruiting actin and inducing its polymerization. here we show that shigella movement within the cytoplasm was severely hindered by microtubules and that the bacteria destroyed surrounding microtubules by secreting vira by means of the type iii secretion system. degradation of microtubules by vira was dependent on its alpha-tubulin-specific cysteine proteas ...200617095701
genetic characterization of multidrug resistance in shigella spp. from japan.this study characterized the genetic basis of antimicrobial resistance of a number of shigella spp. isolated from humans from 2000 to 2004 in hiroshima prefecture, japan. a total of 26 isolates of shigella spp. were included in this study. antimicrobial susceptibility tests revealed high levels of resistance, especially to ampicillin, streptomycin, trimethoprim, tetracycline, nalidixic acid and ciprofloxacin. pcr and dna sequencing were used for screening and characterization of antibiotic-resis ...200617108272
ipad is localized at the tip of the shigella flexneri type iii secretion apparatus.type iii secretion (t3s) systems are used by numerous gram-negative pathogenic bacteria to inject virulence proteins into animal and plant host cells. the core of the t3s apparatus, known as the needle complex, is composed of a basal body transversing both bacterial membranes and a needle protruding above the bacterial surface. in shigella flexneri, ipad is required to inhibit the activity of the t3s apparatus prior to contact of bacteria with host and has been proposed to assist translocation o ...200717110044
enteropathogenic escherichia coli, shigella flexneri, and listeria monocytogenes recruit a junctional protein, zonula occludens-1, to actin tails and pedestals.enteropathogenic escherichia coli, shigella flexneri, and listeria monocytogenes induce localized actin polymerization at the cytoplasmic face of the plasma membrane or within the host cytoplasm, creating unique actin-rich structures termed pedestals or actin tails. the process is known to be mediated by the actin-related protein 2 and 3 (arp2/3) complex, which in these cases acts downstream of neural wiskott-aldrich syndrome protein (n-wasp) or of a listerial functional homolog of wasp family p ...200717118974
a new monoterpene glycoside and antibacterial monoterpene glycosides from paeonia suffruticosa.antibacterial activity-guided fractionation of the chci3-meoh (1:1) extract of paeonia suffruticosa root bark furnished three monoterpene glycosides, 6-o-vanillyoxypaeoniflorin (1), mudanpioside-h (2), and galloyl-oxypaeoniflorin (3). of the isolated compounds, compound 1 is a new compound. all isolated compounds showed broad, but moderate, antibacterial activity with minimum inhibitory concentration (mic) values in the range of 100 to 500 microg/ml against eighteen pathogenic microorganisms of ...200617121173
analysis of fecal leukocytes and erythrocytes in shigella infections in urban bangladesh.we evaluated the usefulness of enumeration of fecal leukocytes and erythrocytes in making an early diagnosis of shigella infection, where shigella is a leading cause of invasive diarrhea. stool specimens from 561 invasive diarrhea patients were submitted for microscopic examination. a presumptive diagnosis of shigellosis based on microscopic examination was made in 389 of them; 227 had stool cultures positive for shigella spp (shigella patients). one hundred sixty-two patients with no detectable ...200617121301
changing epidemiology of shigellosis and emergence of ciprofloxacin-resistant shigellae in india. 200717122011
a microbial diagnostic microarray technique for the sensitive detection and identification of pathogenic bacteria in a background of nonpathogens.a major challenge in microbial diagnostics is the parallel detection and identification of low-bundance pathogens within a complex microbial community. in addition, a high specificity providing robust, reliable identification at least at the species level is required. a microbial diagnostic microarray approach, using single nucleotide extension labeling with gyrb as the marker gene, was developed. we present a novel concept applying competitive oligonucleotide probes to improve the specificity o ...200717123456
the contribution of cytolethal distending toxin to bacterial pathogenesis.cytolethal distending toxin (cdt) is a bacterial toxin that initiates a eukaryotic cell cycle block at the g2 stage prior to mitosis. cdt is produced by a number of bacterial pathogens including: campylobacter species, escherichia coli, salmonella enterica serovar typhi, shigella dystenteriae, enterohepatic helicobacter species, actinobacillus actinomycetemcomitans (the cause of aggressive periodontitis), and haemophilus ducreyi (the cause of chancroid). the functional toxin is composed of three ...200617123907
incidence of enteric bacterial pathogens in water found at the bottom of commercial freezers in calabar, southeastern nigeria.bacteriological analysis of water that accumulates at the bottom of freezers in restaurants when the power was cut in calabar, southeastern nigeria, was carried out using standard procedures. mean heterotrophic bacterial counts and escherichia coli counts ranged from 3.1 +/- 0.02 to 7.1 +/- 0.30 x 10(4) cfu/ml and 0.2 +/- 0.10 to 0.6 +/- 0.50 x 10(4) cfu/ml, respectively, indicating heavy bacterial contamination whose source was mostly fecal. there was no significant difference (p > 0.05, 0.01) ...200617125005
occurrence and diversity of integrons and beta-lactamase genes among ampicillin-resistant isolates from estuarine waters.the aim of the present study was to assess the occurrence and molecular diversity of beta-lactamase genes and integrons among gram-negative ampicillin-resistant bacteria from ria de aveiro. ampicillin-resistant isolates were selected and subjected to genotyping using rep-pcr. representatives from each rep pattern were affiliated with the following taxa by sequencing the 16s rrna gene: aeromonas caviae, a. hydrophila, a. media, a. molluscorum, a. veronii, a. salmonicida, aeromonas sp., pseudomona ...200617125975
salmonella and shigella in freshly squeezed orange juice, fresh oranges, and wiping cloths collected from public markets and street booths in guadalajara, mexico: incidence and comparison of analytical routes.a survey of the presence of salmonella and shigella in freshly squeezed orange juice and related samples was conducted in guadalajara, mexico. one hundred samples of freshly squeezed orange juice were collected from 49 street booths and 51 small food service establishments. in addition, 75 fresh orange samples, each consisting of five orange units, and 75 wiping cloths were collected from the same establishments from which juice had been collected. salmonella was isolated from 14, 20, and 23% of ...200617133801
outbreak of gastroenteritis at a peruvian naval base.in april of 2003, an outbreak of gastroenteritis was reported in a training command (centro de instrucción técnica y entrenamiento naval (citen)) at a peruvian naval base located near lima, peru. the naval medical research center detachment, in collaboration with the national peruvian naval hospital, conducted an investigation to determine the causative agent and potential source of the outbreak. between april 3 and 5, 172 (16%) of 1,092 military trainees reported to the citen clinic with diarrh ...200617153548
occurrence of campylobacter jejuni in shiraz, southwest iran.to investigate the occurrence of campylobacter jejuni among other bacterial agents of acute diarrhea.200717159366
an injected bacterial effector targets chromatin access for transcription factor nf-kappab to alter transcription of host genes involved in immune responses.phosphorylation of histone h3 at ser10 increases chromatin accessibility to transcription factor nf-kappab on a subset of genes involved in immune responses. here we report that a bacterial pathogen abrogated phosphorylation of histone h3 to 'shape' the transcriptional responses of infected host cells. we identify the shigella flexneri protein effector ospf as a dually specific phosphatase that dephosphorylated mitogen-activated protein kinases in the nucleus, thus preventing histone h3 phosphor ...200717159983
revisiting the molecular evolutionary history of shigella spp.the theory that shigella is derived from multiple independent origins of escherichia coli (pupo et al. 2000) has been challenged by recent findings that the virulence plasmids (vps) and the chromosomes share a similar evolutionary history (escobar-paramo et al. 2003), which suggests that an ancestral vp entered an e. coli strain only once, which gave rise to shigella spp. in an attempt to resolve these conflicting theories, we constructed three phylogenetic trees in this study: a robust chromoso ...200717160643
[acute dysentery shigella sonnei outbreak in child day care center: study of the source of infection]. 200617163149
serological cross-reactivity of environmental isolates of enterobacter, escherichia, stenotrophomonas, and aerococcus with shigella spp.-specific antisera.using protocols designed for the isolation of shigella from environmental freshwater samples from different regions of bangladesh, 11 bacterial strains giving rise to shigella-like colonies on selective agar plates and showing serological cross-reaction with shigella-specific antisera were isolated. phylogenetic analyses revealed that three of the isolates were most closely related to escherichia coli, four to enterobacter sp., two to stenotrophomonas, and two isolates belonged to the gram-posit ...200717171463
shigella ipgb1 promotes bacterial entry through the elmo-dock180 machinery.shigella use a special mechanism to invade epithelial cells called 'the trigger mechanism of entry', which allows epithelial cells to trap several bacteria simultaneously. on contact, shigella deliver effectors into epithelial cells through the type iii secretion system. here, we show that one of the effectors, ipgb1, has a pivotal role in producing membrane ruffles by exploiting the rhog-elmo-dock180 pathway to stimulate rac1 activity. using pulldown assays, we identified engulfment and cell mo ...200717173036
vaccine potential for inactivated shigellae.we used human monocyte-derived dendritic cells (dc) and balb/c mice as models to establish the immunogenic and protective potential of formalin-inactivated shigella spp. incubation of dc with inactivated or live bacteria induced dc maturation and cytokine release. mice immunized orally or intranasally with killed s. flexneri, s. sonnei, or s. dysenteriae developed igg and fecal iga titers to the homologous lps. following respiratory challenge with the live homologous organisms, 80-100% survival ...200717178431
shigella rewrites host transcriptional responses. 200717179964
live-attenuated shigella vaccines.several live-attenuated shigella vaccines, with well-defined mutations in specific genes, have shown great promise in eliciting significant immune responses when given orally to volunteers. these responses have been measured by evaluating antibody-secreting cells, serum antibody levels and fecal immunoglobulin a to bacterial lipopolysaccharide and to individual bacterial invasion plasmid antigens. in this review, data collected from volunteer trials with live shigella vaccines from three differe ...200617181440
villin severing activity enhances actin-based motility in vivo.villin, an actin-binding protein associated with the actin bundles that support microvilli, bundles, caps, nucleates, and severs actin in a calcium-dependant manner in vitro. we hypothesized that the severing activity of villin is responsible for its reported role in enhancing cell plasticity and motility. to test this hypothesis, we chose a loss of function strategy and introduced mutations in villin based on sequence comparison with capg. by pyrene-actin assays, we demonstrate that this mutant ...200717182858
structural and genetic evidence that the escherichia coli o148 o antigen is the precursor of the shigella dysenteriae type 1 o antigen and identification of a glucosyltransferase gene.shigella dysenteriae type 1 is the most virulent serotype of shigella. enterotoxigenic escherichia coli o148 is pathogenic and can cause diarrhoea. the following structure was established for the tetrasaccharide repeating unit of the e. coli o148 o antigen: -->3)-alpha-l-rhap-(1-->3)-alpha-l-rhap-(1-->2)-alpha-d-glcp-(1-->3)-alpha-d-glcpnac-(1-->. this differs from the structure reported earlier for s. dysenteriae type 1 by having a glucose (glc) residue in place of a galactose (gal) residue. th ...200717185542
gene cluster analysis method identifies horizontally transferred genes with high reliability and indicates that they provide the main mechanism of operon gain in 8 species of gamma-proteobacteria.the formation mechanism of operons remains unresolved: operons may form by rearrangements within a genome or by acquisition of genes from other species, that is, horizontal gene transfer (hgt). one hindrance to its elucidation is the unavailability of a method to accurately identify hgt, although it is generally considered to occur. it is critically important first to select horizontally transferred (ht) genes reliably and then to determine the extent to which hgt is involved in operon formation ...200717185745
enterobacteriaceae in dehydrated powdered infant formula manufactured in indonesia and malaysia.to determine the occurrence of salmonella and shigella in infant formula from southeast asia, 74 packages of dehydrated powdered infant follow-on formula (recommended age, > 4 months) from five different manufacturers, four from indonesia and one from malaysia, were analyzed. none of the 25-g test portions yielded salmonella or shigella. however, further identification of colonies growing on selective media used for salmonella and shigella detection revealed the frequent occurrence of several ot ...200617186672
use of linear, weibull, and log-logistic functions to model pressure inactivation of seven foodborne pathogens in milk.survival curves of six foodborne pathogens suspended in ultra high-temperature (uht) whole milk and exposed to high hydrostatic pressure at 21.5 degrees c were obtained. vibrio parahaemolyticus was treated at 300 mpa and other pathogens, listeria monocytogenes, escherichia coli o157:h7, salmonella enterica serovar enteritidis, salmonella enterica serovar typhimurium, and staphylococcus aureus were treated at 600 mpa. all the survival curves showed a rapid initial drop in bacterial counts followe ...200717188197
polar positional information in escherichia coli spherical cells.shigella surface protein icsa and its cytoplasmic derivatives are localized to the old pole of rod-shaped cells when expressed in escherichia coli. in spherical mreb cells, icsa is targeted to ectopic sites and close to one extremity of actin-like mamk filament. to gain insight into the properties of the sites containing polar material, we studied the icsa localization in spherical cells. gfp was exported into the periplasm via the tat pathway and used as a periplasmic space marker. gfp displaye ...200717188233
[time course changes in cytokines content and gas composition in blood of patients with salmonellosis and acute shigellosis].to study changes in serum concentrations of interleukines (il) and tumor necrosis factor alpha (tnfa) in the course of acute moderate and severe shigellosis and salmonellosis; to elicit their correlation with disorders of gas and electrolyte blood composition and acid-base balance (abb).200617195521
case-control study of shigellosis in san francisco: the role of sexual transmission and hiv infection.shigella species infect approximately 450,000 persons annually in the united states. person-to-person transmission of shigella species, which have a low infectious dose, occurs frequently, particularly in areas with poor sanitation and hygiene. sexual transmission of shigella species among men who have sex with men (msm) has been inferred from outbreaks of shigellosis among that population, and limited studies have suggested the importance of human immunodeficiency virus (hiv) infection as a ris ...200717205436
another perfect storm: shigella, men who have sex with men, and hiv. 200717205437
[short communication: prevalence of extended spectrum beta-lactamases in gram negative rods: data of 2001-2004 period].this study was undertaken to determine the prevalence of extended spectrum beta-lactamase (esbl) production by gram negative rods (gnrs) isolated from various clinical specimens (3.240 urine, 336 pus, 277 feces, 83 blood, 38 sputum) sent to our hospital laboratory, between 2001-2004. of isolated bacteria 71.4% were identified as escherichia coli, 11.1% were klebsiella spp, 4.2% were salmonella spp, 3.7% were pseudomonas spp, 3.5% were proteus spp, 2.9% were shigella spp, 2.3% were enterobacter s ...200617205693
shigella's ways of manipulating the host intestinal innate and adaptive immune system: a tool box for survival?shigella, a gram-negative invasive enteropathogenic bacterium, causes the rupture, invasion and inflammatory destruction of the human colonic epithelium. this complex and aggressive process accounts for the symptoms of bacillary dysentery. the so-called invasive phenotype of shigella is linked to expression of a type iii secretory system (ttss) injecting effector proteins into the epithelial cell membrane and cytoplasm, thereby inducing local but massive changes in the cell cytoskeleton that lea ...200717213832
campylobacter diarrhea in alexandria, egypt.the role of campylobacter as a cause of bacterial diarrhea in young children in alexandria, egypt was investigated. stools or rectal swabs were collected from 880 children (mean age 9.8 months) presenting to a hospital with the primary complaint of diarrhea and from 1,079 well children (mean age 8.8 months) attending a vaccination clinic. isolation of campylobacter was significantly (p<0.0002) more frequent from cases (17.2%) than from controls (6.4%). campylobacter was isolated from children pr ...199517214155
bacteriological quality of ready to eat meals.microbial investigation of 30 samples of roasted liver and 30 samples of meat sandwiches, collected randomly from different peddlers and restaurants in alexandria city, was conducted to evaluate their sanitary status. the average count/gm of total aerobic bacterial count thermophilic, total coliform and faecal coliform counts isolated from liver sandwiches were 8.11 x 10(6), 1.05 x 10(5) and 9.04 x 10(3), but from meat sandwiches (shawerma) were 7.06 x 10(4), 6.24 x 10(3), 2.26 x 10(3) and 1.09 ...199517214179
shigella chromosomal ipah proteins are secreted via the type iii secretion system and act as effectors.shigella possess 220 kb plasmid, and the major virulence determinants, called effectors, and the type iii secretion system (ttss) are exclusively encoded by the plasmid. the genome sequences of s. flexneri strains indicate that several ipah family genes are located on both the plasmid and the chromosome, but whether their chromosomal ipah cognates can be secreted from shigella remains unknown. here we report that s. flexneri strain, ysh6000 encodes seven ipah cognate genes on the chromosome and ...200717214743
screening of some food poisoning bacteria in sausage and hamburger meat.microbial investigation of 30 samples of sausage meat and 30 samples of hamburger meat, freshly prepared, were collected randomly from different markets in alexandria city, to determine the bacteriological status of these products. the average counts/gm of total bacteria, total coliforms and fecal coliform in sausage meat were 1.33 x 10(7), 9.16 x 10(5) and 1.11 x 10(3) respectively, and in hamburger samples were 8.47 x 10(5), 2.63 x 10(3) and 1.35 x 10(3) respectively. shigella, escherichia col ...199617217001
[detection of class i integron and its relation to antimicrobial resistance of shigella flexneri in children].to investigate class i integron of shigella flexneri, its prevalence in children, and its relation to bacterial resistance to antimicrobial agents.200617217663
an h-ns-like stealth protein aids horizontal dna transmission in bacteria.the sfh protein is encoded by self-transmissible plasmids involved in human typhoid and is closely related to the global regulator h-ns. we have found that sfh provides a stealth function that allows the plasmids to be transmitted to new bacterial hosts with minimal effects on their fitness. introducing the plasmid without the sfh gene imposes a mild h-ns(-) phenotype and a severe loss of fitness due to titration of the cellular pool of h-ns by the a+t-rich plasmid. this stealth strategy seems t ...200717218529
erosion of interaction networks in reduced and degraded genomes.unlike eukaryotes, which often recruit duplicated genes into existing protein-protein interaction (ppi) networks, the low levels of gene duplication coupled with the high probability of lateral transfer of novel genes alters the manner in which ppi networks can evolve in bacteria. by inferring the ppis present in the ancestor to contemporary gammaproteobacteria, we were able to trace the changes in gene repertoires, and their consequences on ppi network evolution, in several bacterial lineages t ...200717219366
analysis of strategies to successfully vaccinate infants in developing countries against enterotoxigenic e. coli (etec) disease.enterotoxigenic escherichia coli (etec) is the most common bacterial cause of diarrhoea in the world, annually affecting up to 400,000,000 children under 5 years of age living in developing countries (dcs). although etec possesses numerous antigens, the relatively conserved colonization factor (cf) antigens and the heat labile enterotoxin (lt) have been associated with protection and most vaccine candidates have exploited these antigens. a safe and effective vaccine against etec is a feasible go ...200717224212
antibacterial activity and in vitro anti-tumor activity of the extract of the larvae of the housefly (musca domestica).one of the significant characteristics of traditional chinese medicine is the use of insects, other terrestrial arthropods and their products as drugs. in the present work, the extract of housefly (musca domestica) larvae was studied by an agar well diffusion assay and minimum bactericidal concentration (mbc) determination for detection of antimicrobial activity and by mtt assay method to test its in vitro anti-tumor activity. in our studies, the extract inhibited six tested bacterial pathogens ...200717227700
immunogenicity and characterization of wrsf2g11: a second generation live attenuated shigella flexneri 2a vaccine strain.recent clinical trials involving live attenuated shigella vaccine strains sc602 and wrss1 have revealed that deletion of the virg(icsa) gene dramatically reduces virulence in human volunteers. these strains can be given at low oral doses and induce a strong, and in some cases, protective immune responses. however, residual vaccine associated reactogenicity suggests that further attenuation is required. a recent clinical trial indicated that the set and sen enterotoxin genes contribute to the sym ...200717229494
role of infection in irritable bowel syndrome.infection by pathogenic organisms leads to mucosal damage and disruption of the gut's extensive commensal flora, factors which may lead to prolonged bowel dysfunction. six to 17% of unselected irritable bowel syndrome (ibs) patients believe their symptoms began with an infection, which is supported by prospective studies showing a 4%-31% incidence of postinfectious ibs-(pi) following bacterial gastroenteritis. the wide range of incidence can be accounted for by differences in risk factors, which ...200717238025
using european travellers as an early alert to detect emerging pathogens in countries with limited laboratory resources.the volume, extent and speed of travel have dramatically increased in the past decades, providing the potential for an infectious disease to spread through the transportation network. by collecting information on the suspected place of infection, existing surveillance systems in industrialized countries may provide timely information for areas of the world without adequate surveillance currently in place. we present the results of a case study using reported cases of shigella dysenteriae serotyp ...200717239228
high genetic stability of integrons in clinical isolates of shigella spp. of worldwide origin.over a 12-year period, 68 shigella strains (31 s. sonnei, 30 s. flexneri, 4 s. dysenteriae, and 3 s. boydii strains) were collected in a french university hospital from the stools of patients who generally had a recent history of travel to various parts of the world (91%), particularly africa (67%). these strains were often resistant (streptomycin, spectinomycin, trimethoprim, tetracycline, and sulfonamides, 66 to 84%; ampicillin and chloramphenicol, 34 to 38%; nalidixic acid, 4%) and even multi ...200717242143
the catalase reaction of shigella species and its use in rapid screening for epidemic shigella dysenteriae type 1.as epidemic dysentery caused by shigella dysenteriae type 1 is associated with high mortality, early identification of outbreaks is important. since s. dysenteriae type 1 differs from most of the enterobacteriaceae in that it does not produce catalase, a test for catalase may provide a useful screening method. the ability of a catalase test to provide rapid identification of s. dysenteriae type 1 has now been assessed, using isolates of this pathogen from five continents, shigella of other speci ...200717244412
[dysentery in poland in 2004].the number of notified dysentery cases is the lowest of all years since 1918 when notification started. only 74 cases were notified in the year 2004 (incidence rate 0.19/100,000 population) while 220 cases were registered in 2002 (incidence 0.58/100,000 population). no one death case was notified. the last three death cases were notified in 1999. two dysentery outbreaks (due to s. flexneri 3a): were notified when the outbreaks of food poisoning were examined by regional laboratory of sanitary-ep ...200617249165
antimicrobial resistance patterns in enterobacteriaceae isolated from an urban wastewater treatment plant.over 18 months, enterobacteria were isolated from the raw (189 isolates) and treated (156 isolates) wastewater of a municipal treatment plant. the isolates were identified as members of the genera escherichia (76%), shigella (7%), klebsiella (12%) and acinetobacter (4%). antimicrobial susceptibility phenotypes were determined using the agar diffusion method for the antibiotics amoxicillin, gentamicin, ciprofloxacin, sulfamethoxazole/trimethoprim, tetracycline and cephalothin, the disinfectants h ...200717250754
in-vitro antibacterial, antifungal and cytotoxic activity of cobalt (ii), copper (ii), nickel (ii) and zinc (ii) complexes with furanylmethyl- and thienylmethyl-dithiolenes: [1, 3-dithiole- 2-one and 1,3-dithiole-2-thione].some antibacterial and antifungal furanylmethyl-and thienylmethyl dithiolenes and, their co(ii), cu(ii), ni (ii) and zn (ii) complexes have been synthesized, characterized and screened for their in vitro antibacterial activity against four gram-negative; escherichia coli, pseudomonas aeruginosa, salmonella typhi and shigella flexeneri, and two gram-positive; bacillus subtilis and staphylococcus aureus bacterial strains, and for in-vitro antifungal activity against trichophyton longifusus, candid ...200617252947
in-vitro antibacterial, antifungal and cytotoxic properties of metal-based furanyl derived sulfonamides.a new series of antibacterial and antifungal furanyl-derived sulfonamides and their cobalt (ii), copper (ii), nickel (ii) and zinc (ii) metal complexes have been synthesized, characterized and screened for their in-vitro antibacterial activity against four gram-negative (escherichia coli, shigella flexneri, pseudomonas aeruginosa and salmonella typhi) and two gram-positive (bacillus subtilis and staphylococcus aureus) bacterial strains and, for in-vitro antifungal activity against trichophyton l ...200617252952
extended-spectrum beta-lactamase-producing shigella strains in israel, 2000-2004.routine susceptibility testing of 5,616 shigella isolates at the national shigella reference centre in israel over a 5-year period (2000-2004) revealed resistance to ceftriaxone in one strain of shigella boydii 2 and in two strains each of shigella flexneri 2a, s. flexneri 6, and shigella sonnei. all seven isolates were confirmed as producers of extended-spectrum beta-lactamase (esbl) by the combination disk method, the vitek 1 system, and a modification of the double-disk synergy test, which is ...200717265070
epidemiological characterization of resistance and pcr typing of shigella flexneri and shigella sonnei strains isolated from bacillary dysentery cases in southeast brazil.shigella spp are gram-negative, anaerobic facultative, non-motile, and non-sporulated bacilli of the enterobacteriaceae family responsible for "shigellosis" or bacillary dysentery, an important cause of worldwide morbidity and mortality. however, despite this, there are very few epidemiological studies about this bacterium in brazil. we studied the antibiotic resistance profiles and the clonal structure of 60 shigella strains (30 s. flexneri and 30 s. sonnei) isolated from shigellosis cases in d ...200717273662
new animal model of shigellosis in the guinea pig: its usefulness for protective efficacy studies.it has been difficult to evaluate the protective efficacy of vaccine candidates against shigellosis, a major form of bacillary dysentery caused by shigella spp. infection, because of the lack of suitable animal models. to develop a proper animal model representing human bacillary dysentery, guinea pigs were challenged with virulent shigella flexneri serotype 2a (strains 2457t or ysh6000) or s. flexneri 5a (strain m90t) by the intrarectal (i.r.) route. interestingly, all guinea pigs administered ...200717277155
bioluminescent signal system: bioluminescence immunoassay of pathogenic organisms.the ca(2+)-regulated photoprotein obelin has been examined as a label for bioluminescence immunoassay of infective agents. the hepatitis b virus (hbsag) and the bacteria escherichia coli and shigella sonnei lipopolysaccharide (lps) were chosen as model antigens. chemically synthesized obelin-corresponding antibody conjugates were used in a solid-phase microplate immunoassay. the sensitivities achieved by the assay were 0.25 ng/ml for s. sonnei lps and 0.375 ng/ml for hbsag. a novel, filter-based ...200717286244
gene expression profiling of the ph response in shigella flexneri 2a.the ph response of shigella flexneri 2a 301 was identified by gene expression profiling. gene expression profiles of cells grown in ph 4.5 or 8.6 were compared with the profiles of cells grown at ph 7.0. differential expression was observed for 307 genes: 97 were acid up-regulated, 102 were acid down-regulated, 91 were base up-regulated, and 86 were base down-regulated. twenty-seven genes were found to be both acid and base up-regulated, and 29 genes were both acid and base down-regulated. this ...200717286558
o-specific [corrected] polysaccharide conjugate vaccine-induced [corrected] antibodies prevent invasion of shigella into caco-2 cells and may be curative.the o-specific polysaccharide (o-sp) domain of shigella lps is both an essential virulence factor and a protective antigen for this genus. a critical level of serum igg anti-o-sp was shown to confer immunity to shigellosis, likely by complement-mediated bacteriolysis of the inoculum. conjugate shigella o-sp vaccines were shown to be safe and immunogenic in children, and, in a preliminary study, shigella sonnei vaccine was protective in young adults. characteristic of shigellosis is bacterial inv ...200717287349
capping of actin filaments by vinculin activated by the shigella ipaa carboxyl-terminal domain.shigella, the causative agent of bacillary dysentery, invades epithelial cells. upon bacterial-cell contact, the type iii bacterial effector ipaa binds to the cytoskeletal protein vinculin to promote actin reorganization required for efficient bacterial uptake. we show that the last 74 c-terminal residues of ipaa (a559) bind to human vinculin (hv) and promotes its association with actin filaments. polymerisation experiments demonstrated that a559 was sufficient to induce hv-dependent partial cap ...200717289036
seasonality in six enterically transmitted diseases and ambient temperature.we propose an analytical and conceptual framework for a systematic and comprehensive assessment of disease seasonality to detect changes and to quantify and compare temporal patterns. to demonstrate the proposed technique, we examined seasonal patterns of six enterically transmitted reportable diseases (eds) in massachusetts collected over a 10-year period (1992-2001). we quantified the timing and intensity of seasonal peaks of ed incidence and examined the synchronization in timing of these pea ...200717291363
study of polymorphic variable-number of tandem repeats loci in the ecor collection and in a set of pathogenic escherichia coli and shigella isolates for use in a genotyping assay.the escherichia coli (e. coli) reference collection, ecor, consists of 72 strains that are representative of the genotypic diversity, as indexed by multilocus enzyme electrophoresis (mlee), in the species as a whole. mlee revealed 4 main phylogenetic groups designated a, b1, b2 and d. we present a study of the relationship between the ecor strains as determined by polymorphisms in seven variable-number of tandem repeats (vntr) loci. seven tandem repeats that were present in more than one of the ...200717291612
production, characterization, and application of antibodies against heat-labile type-i toxin for detection of enterotoxigenic escherichia coli.strains of enterotoxigenic escherichia coli (etec) are responsible for significant rates of morbidity and mortality among children, particularly in developing countries. the majority of clinical and public health laboratories are capable of isolating and identifying salmonella, shigella, campylobacter, and escherichia coli o157:h7 from stool samples, but etec cannot be identified by routine methods. the method most often used to identify etec is polymerase chain reaction for heat-stable and heat ...200617293982
monitoring of pathogenicity of effluents from the uasb based sewage treatment plant.the microbial profile of an upflow anaerobic sludge blanket reactor based sewage treatment plant located at a suburb of delhi, india, and possible risk due to the pathogenicity of the treated wastewater was investigated. frequency of occurrence of salmonella, shigella and vibrio was 100% at all the stages of sewage treatment. however, recovery of vibrio was the highest among all the pathogens. the order of removal of all the pathogens was same at the different stages of the treatment. ratio of c ...200717295111
bile salts stimulate recruitment of ipab to the shigella flexneri surface, where it colocalizes with ipad at the tip of the type iii secretion needle.shigella flexneri uses its type iii secretion apparatus (ttsa) to deliver invasins into human cells. this ttsa possesses an external needle with ipad at its tip. we now show that deoxycholate promotes the stable recruitment of ipab to the needle tip without inducing a rapid burst of type iii secretion. the maintenance of ipab at the needle tip requires a stable association of ipad with the shigella surface. this is the first demonstration of a translocator protein being stably associated with th ...200717296762
[pyrazinamidase activity of bacteria from enterobacteriaceae family as characteristic for taxonomy].pyrazinamidase activity in 330 strains of bacteria from enterobacteriaceae family (14 genus, 27 species) has been assessed. pyrazinamidase activity detected in species from following genuses: citrobacter, escherichia, klebsiella, kluyvera, morganella, providencia, raourtella, salmonella, shigella, and also in proteus mirabilis, and nonpathogenic serovars of yersinia enterocolitica, y. frederiksenii. pirasinamidase was absent in serratia (s. marcescens, s. liguefaciens), hafnia alvei, p. vulgaris ...200617297889
norovirus outbreak in a district general hospital--new strain identified.media reports about norovirus outbreaks, especially in hospitals and nursing homes, have accumulated in the past years. the reasons for this increasing problem are manifold: resistance against common disinfectants, a high level of contagion (a dose of less than 100 particles may be infective); variability of the virus-genome documented by polymerase chain reaction-studies, as well as further factors concerning modern life-style. the following study describes and analyses a norovirus outbreak in ...200717299671
evaluation of an enzyme immunoassay-based stool antigen test to detect campylobacter jejuni and campylobacter coli.an enzyme immunoassay-based antigen test (ridascreen campylobacter; r-biopharm, darmstadt, germany) was evaluated for the detection of campylobacter jejuni and campylobacter coli in 1050 clinical stool samples as compared with culture on selective medium. after routine inoculation for salmonella, shigella, yersinia, aeromonas, plesiomonas, and campylobacter, the same swab specimens were used for the antigen test. the positivity rate for campylobacter was 9.3% in culture, and the antigen test gav ...200717300899
the phosphothreonine lyase activity of a bacterial type iii effector family.pathogenic bacteria use the type iii secretion system to deliver effector proteins into host cells to modulate the host signaling pathways. in this study, the shigella type iii effector ospf was shown to inactivate mitogen-activated protein kinases (mapks) [extracellular signal-regulated kinases 1 and 2 (erk1/2), c-jun n-terminal kinase, and p38]. ospf irreversibly removed phosphate groups from the phosphothreonine but not from the phosphotyrosine residue in the activation loop of mapks. mass sp ...200717303758
yeast functional genomic screens lead to identification of a role for a bacterial effector in innate immunity regulation.numerous bacterial pathogens manipulate host cell processes to promote infection and ultimately cause disease through the action of proteins that they directly inject into host cells. identification of the targets and molecular mechanisms of action used by these bacterial effector proteins is critical to understanding pathogenesis. we have developed a systems biological approach using the yeast saccharomyces cerevisiae that can expedite the identification of cellular processes targeted by bacter ...200717305427
the role of the vacb gene in the pathogenesis of brucella abortus.brucella species are important zoonotic pathogens affecting a wide variety of mammals. therefore, the identification of new brucella virulence factors is of great interest in understanding bacterial pathogenesis and immune evasion. in this study, we have identified brucella abortus vacb gene that presents 2343 nucleotides and 781 amino acids and it shows 39% identity with shigella flexneri vacb gene that encodes an exoribonuclease rnase r involved in bacterial virulence. further, we have inactiv ...200717306588
Displaying items 11901 - 12000 of 13650