Publications

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Reactor performance and bacterial pathogen removal in response to sludge retention time in a mesophilic anaerobic digester treating sewage sludge.The effects of sludge retention time (SRT) on reactor performance and bacterial pathogen removal of sludge mesophilic anaerobic digestion (MAD) were investigated in a continuous stirred tank reactor. The average volatile solids removal remained around 20% and the biogas production rate varied from 100 to 132ml/ld. The MAD process was efficient to remove Salmonella sp. and Escherichia coli with removal efficiencies increased with SRT from 11d, 16d to 25d. However, the Shigella sp. removal was ins ...201122197074
analysis of synonymous codon usage in shigella flexneri 2a strain 301 and other shigella and escherichia coli strains.in this study, we analysed synonymous codon usage in shigella flexneri 2a strain 301 (sf301) and performed a comparative analysis of synonymous codon usage patterns in sf301 and other strains of shigella and escherichia coli. although there was a significant variety in codon usage bias among different sf301 genes, there was a slight but observable codon usage bias that could primarily be attributable to mutational pressure and translational selection. in addition, the relative abundance of dinuc ...201122112197
Ciprofloxacin-resistant Shigella sonnei among men who have sex with men, Canada, 2010.In 2010, we observed isolates with matching pulsed-field gel electrophoresis patterns from 13 cases of ciprofloxacin-resistant Shigella sonnei in Montréal. We report on the emergence of this resistance type and a study of resistance mechanisms. The investigation suggested local transmission among men who have sex with men associated with sex venues.201121888811
characterization of a vii-like phage specific to escherichia coli o157:h7.phage vb_ecom_cba120 (cba120), isolated against escherichia coli o157:h7 from a cattle feedlot, is morphologically very similar to the classic phage vii of salmonella enterica serovar typhi. until recently, little was known genetically or physiologically about the vii-like phages, and none targeting e. coli have been described in the literature. the genome of cba120 has been fully sequenced and is highly similar to those of both vii and the shigella phage ag3. the core set of structural and repl ...201121899740
Further characterization of Shigella sonnei live vaccine candidates WRSs2 and WRSs3-plasmid composition, invasion assays and Sereny reactions. 201121983066
Clinical characteristics and antibiotic resistance of Shigella gastroenteritis in Ankara, Turkey between 2003 and 2009, and comparison with previous reports.The aim of this study was to define the epidemiological, clinical, and antibiotic susceptibility patterns of Shigella gastroenteritis cases occurring during the years 2003-2009 and to compare results with those of the years 1987-2002.201121982814
convergent synthesis of the tetrasaccharide repeating unit of the o-antigen of shigella boydii type 9.a convenient synthesis of the tetrasaccharide repeating unit of the o-antigen of shigella boydii type 9 has been achieved in excellent yield using a [2 + 2] block glycosylation strategy. tempo-mediated selective oxidation of the primary alcohol of the tetrasaccharide derivative 8 to the carboxylic group followed by deprotection of the functional groups furnished target tetrasaccharide 1 as its 4-methoxyphenyl glycoside in high yield.201121977201
synthesis of novel quinoxalinone derivatives by conventional and microwave methods and assessing their biological activity.in this study, twenty-one arylaminoquinoxalinone derivatives were synthesized and their antibacterial activities against staphylococci aureus, pseudomonas aureus, escherichia coli, bacillus subtilis, salmonella typhi, and shigella pneumoniae were evaluated relative to known antibiotics; augmentin, ampicillin, and chloramphenicol. the insecticidal activities of the prepared compounds were also investigated against tribolium castaneum using permethrin as a standard insecticide. the derivatives wer ...201122076760
the role of oxyr and soxrs in oxidative stress survival in shigella flexneri.shigella flexneri, a facultative intracellular pathogen, is exposed to a variety of environments inside and outside of the human host. some of these environments may contain significant oxidative stress. s. flexneri mutants were generated with deletions in the major oxidative stress regulators oxyr and/or soxrs to test their importance in shigella biology. strains that contained a deletion of oxyr had reduced growth and survival during aerobic growth, but not microaerobic growth. the mutants wer ...201122015257
live attenuated shigella dysenteriae type 1 vaccine strains overexpressing shiga toxin b subunit.shigella dysenteriae serotype 1 (s. dysenteriae 1) is unique among the shigella species and serotypes in the expression of shiga toxin which contributes to more severe disease sequelae and the ability to cause explosive outbreaks and pandemics. s. dysenteriae 1 shares characteristics with other shigella species, including the capability of causing clinical illness with a very low inoculum (10 to 100 cfu) and resistance to multiple antibiotics, underscoring the need for efficacious vaccines and t ...201121969003
Comparative evaluation of the antibody in lymphocyte supernatant (ALS) and enzyme-linked immunospot (ELISPOT) assays for measuring mucosal immune responses to Shigella antigens.Accurately assessing mucosal immune responses to candidate vaccines remains a technical challenge. ELISPOT is widely used as a surrogate of mucosal immune response by directly enumerating circulating antibody secreting cells (ASCs), while antibody in lymphocyte supernatant (ALS) titers the total amount of antibody secreted by ASC ex vivo using ELISA. ALS is more practical than ELISPOT because the ASC supernatant is frozen for ELISA that can be conducted at any time, with any antigen, and in any ...201121939714
Nicotinamide dependence of uropathogenic Escherichia coli UTI89 and application of nadB as a neutral insertion site.NAD and NADP function ubiquitously in the metabolism of Escherichia coli K-12. NAD auxotrophy can be rendered by mutation in any of the three genes, nadB, nadA, and nadC. The nadB and nadA genes were defined as anti-virulence loci in Shigella spp., as a mutation (mainly in nadB) disrupting the synthesis of quinolinate is required for virulence. Uropathogenic E. coli (UPEC) isolates, from acute cystitis patients, exhibiting nicotinamide auxotrophy were of serotype O18:K1:H7. E. coli UTI89, the mo ...201122174382
gadd45a activity is the principal effector of shigella mitochondria-dependent epithelial cell death in vitro and ex vivo.modulation of death is a pathogen strategy to establish residence and promote survival in host cells and tissues. shigella spp. are human pathogens that invade colonic mucosa, where they provoke lesions caused by their ability to manipulate the host cell responses. shigella spp. induce various types of cell death in different cell populations. however, they are equally able to protect host cells from death. here, we have investigated on the molecular mechanisms and cell effectors governing the b ...201121368893
Detection of diarrhoeal pathogens in human faeces using an automated, robotic platform.Infectious diarrhoeal diseases represent a major socio-economic burden to humans, and are linked to a range of pathogens, including viruses, bacteria and protists. The accurate detection of such pathogens is central to control. However, detection often relies on methods that have limited diagnostic sensitivity and specificity. Here, we assessed an automated, robotic platform for the simultaneous detection of eight major pathogens associated with infectious diarrhoea. Genomic DNA samples (n = 167 ...201122056326
Genotyping of selected bacterial enteropathogens in Norway.In Norway the Norwegian Institute of Public Health (NIPH) is the primary facility for nationwide surveillance of foodborne infections, and it is vital that we can perform rapid and high resolution identification of foodborne bacteria at the strain level. During the last decade a rapid introduction of DNA-based methods has been introduced, which show promise in enhancing the speed and discriminatory capability of the typing laboratory. The laboratory responsible for genotyping enteropathogens at ...201121975141
Third-generation cephalosporin resistance in clinical isolate of Shigella sonnei in Andaman & Nicobar Islands, India. 201121918310
Differential host immune responses to epidemic and endemic strains of Shigella dysenteriae type I.Shigella dysenteriae type 1 causes devastating epidemics in developing countries with high case-fatality rates in all age-groups. The aim of the study was to compare host immune responses to epidemic (T2218) and endemic strains of S. dysenteriae type 1. Shigellacidal activity of serum from rabbits immunized with epidemic or endemic strains, S. dysenteriae type 1-infected patients, and healthy adult controls from Shigella-endemic and non-endemic regions was measured. Immunogenic cross-reactivity ...201122106748
Natural Products Modulate Shigella-Host Cell Interaction.This study focussed on identifying possible new options derived from natural sources for the treatment of bacterial infections. Several natural products were investigated for their potential in modulating Shigella-host cell interaction. The proliferation of Shigella sonnei was effectively inhibited inside HEp-2 cells in the presence of 4-methoxycinnamic acid and propolin D. Propolin D also significantly reduced the apopotosis of infected macrophage-like U937 cells, and moderately reduced the sec ...201121719574
antisense inhibition of gene expression and growth in gram-negative bacteria by cell-penetrating peptide conjugates of peptide nucleic acids targeted to rpod gene.gram-negative bacteria (gnb) cause common and severe hospital- and community-acquired infections with a high incidence of multidrug resistance (mdr) and mortality. the emergence and spread of mdr-gnb strains limit therapeutic options and highlight the need to develop new therapeutic strategies. in this study, the peptide (rxr)(4)xb- and (kff)(3)k-conjugated peptide nucleic acids (ppnas) were developed to target rpod, which encodes an rna polymerase primary σ(70) that is thought to be essential f ...201122000398
bacteriological assessment of drinking water supply options in coastal areas of bangladesh.this study was conducted to assess the bacteriological quality of alternative drinking water supply options in southwest coastal areas of bangladesh. a total of 90 water samples were collected during both dry and wet seasons from household based rainwater harvesting systems (rwhss), community based rain water harvesting systems (crwhss), pond-sand filters (psfs) and ponds. the samples were evaluated for faecal coliform, escherichia coli and heterotrophic plate count, as well as vibrio cholerae, ...201121942205
gene decay in shigella as an incipient stage of host-adaptation.background: many facultative bacterial pathogens have undergone extensive gene decay processes, possibly due to lack of selection pressure during evolutionary conversion from free-living to intracellular lifestyle. shigella, the causative agents of human shigellosis, have arisen from different e. coli-like ancestors independently by convergent paths. as these bacteria all have lost large numbers of genes by mutation or deletion, they can be used as ideal models for systematically studying the pr ...201122110755
chemical and antidiarrheal studies of plinia cauliflora.plinia cauliflora (mart.) kausel, widespread in south america, has edible fruits, and its bark is commonly used against diarrhea and other disorders, on account of its astringency. because diarrhea is still one of the most important causes of illness and death among children in developing countries, where the population turns to traditional medicine for its treatment, the present study determined the composition of fruit and leaf extracts of p. cauliflora, analyzed the activity against diarrhea ...201121861716
Within-species lateral genetic transfer and the evolution of transcriptional regulation in Escherichia coli and Shigella.Changes in transcriptional regulation underlie many of the phenotypic differences observed within and between species of bacteria. Lateral genetic transfer (LGT) can significantly impact the transcription factor (TF) genes which drive these transcriptional changes. Although much emphasis has been placed on LGT of intact genes, the units of transfer and recombination do not necessarily correspond to regions delineated by exact gene boundaries. Here we apply phylogenetic and network-based methods ...201122035052
Differentiation between Shigella, enteroinvasive Escherichia coli (EIEC) and noninvasive Escherichia coli.Shigella causes bacillary dysentery and is classified into four species based on their antigen characteristics. This classification does not reflect genetic relatedness; in fact, Shigella species are so related to Escherichia coli , they should be classified as one distinctive species in the genus Escherichia. The differentiation of Shigella and E. coli is even more complicated with the description of enteroinvasive E. coli (EIEC). EIEC are strains that possess some of the biochemical characteri ...201121901636
Genesis of a novel Shigella flexneri serotype by sequential infection of serotype-converting bacteriophages SfX and SfI.ABSTRACT: BACKGROUND: Shigella flexneri is the major pathogen causing bacillary dysentery. Fifteen serotypes have been recognized up to now. The genesis of new S. flexneri serotypes is commonly mediated by serotype-converting bacteriophages. Untypeable or novel serotypes from natural infections had been reported worldwide but have not been generated in laboratory. RESULTS: A new S. flexneri serotype-serotype 1 d was generated when a S. flexneri serotype Y strain (native LPS) was sequentially in ...201122208551
[Investigation of verotoxigenic escherichia coli O157:H7 incidence in gastroenteritis patients].Escherichia coli O157:H7 is the most common serotype among verotoxigenic E.coli (VTEC) strains that cause haemolytic uremic syndrome. Although sporadic VTEC cases originating from Turkey and small outbreaks have been reported from our country, VTEC has not been routinely investigated in most of the diagnostic microbiology laboratories in Turkey and studies related to this topic are limited. In this study, the incidence of E.coli O157:H7 in patients who were admitted to Alanya Research and Applic ...201121935785
Mucosal immunization with Shigella flexneri outer membrane vesicles induced protection in mice.Vaccination appears to be the only rational prophylactic approach to control shigellosis. Unfortunately, there is still no safe and efficacious vaccine available. We investigated the protection conferred by a new vaccine containing outer membrane vesicles (OMVs) from Shigella flexneri with an adjuvant based on nanoparticles in an experimental model of shigellosis in mice. OMVs were encapsulated in poly(anhydride) nanoparticles prepared by a solvent displacement method with the copolymer PMV/MA. ...201121911022
Gut microbiota and pediatric disease.Background: Researchers have made every effort to assess the role of gut microbiota in pediatric diseases like inflammatory bowel disease (IBD), celiac disease, asthma, allergy, and autism. The leading hypothesis is that an altered microbial composition is present (other than the presence of a specific pathogen) and that it could be involved in the pathogenesis or progression of such disorders. Methods: Cultural, molecular, metabolomic, and metagenomic approaches are trying to define the pediatr ...201122179208
whole-genome phylogeny of escherichia coli/shigella group by feature frequency profiles (ffps).a whole-genome phylogeny of the escherichia coli/shigella group was constructed by using the feature frequency profile (ffp) method. this alignment-free approach uses the frequencies of l-mer features of whole genomes to infer phylogenic distances. we present two phylogenies that accentuate different aspects of e. coli/shigella genomic evolution: (i) one based on the compositions of all possible features of length l = 24 (∼8.4 million features), which are likely to reveal the phenetic grouping a ...201121536867
rapid situation & response assessment of diarrhoea outbreak in a coastal district following tropical cyclone aila in india.background & objectives : cyclone aila hit indian states on eastern coast on may 25, 2009. an investigation was conducted to examine if aila was responsible for increased reporting of diarrhoea cases from the district of east-medinipur in west bengal. identifying causative organisms for diarrhoea and assessing their antibiotic susceptibility profile were other objectives. methods: rapid situation and response assessment technique was employed to triangulate primary and secondary data collected t ...201121537092
toxic megacolon from sexually transmitted shigella sonnei infection. 201121538050
development of a new guinea-pig model of shigellosis.shigellosis is a major form of bacillary dysentery caused by shigella spp. to date, there is no suitable animal model to evaluate the protective efficacy of vaccine candidates against this pathogen. here, we describe a successful experimental shigellosis in the guinea-pig model, which has shown the characteristic features of human shigellosis. this model yielded reproducible results without any preparatory treatment besides cecal ligation. in this study, guinea-pigs were discretely infected with ...201121539623
effects of probiotic fermentation on the enhancement of biological and pharmacological activities of codonopsis lanceolata extracted by high pressure treatment.this study was designed to evaluate the enhancement of antioxidant, antimicrobial, enzymatic, cytotoxic, and cognitive activities of codonopsis lanceolata extracted by high pressure treatment followed by probiotic fermentation. dried c. lanceolata samples were subjected to 400mpa for 20min and then fermented with bifidobacterium longum b6 (hpe-blf) and lactobacillus rhamnosus (hpe-lrf) at 37°c for 7days. compared to conventional extraction (ce-nf, 6.69mg gae/g), the phenol amounts of hpe-blf and ...201121543255
evaluation of the selective and differential et medium for detection of edwardsiella tarda in aquaculture systems.aims:  edwardsiella tarda is an important pathogen in aquaculture where it can cause serious losses. a rapid detection of it is vital to minimize the mortalities caused by this disease, and in this work, the effectiveness of the selective differential edw. tarda medium (et) was evaluated for the diagnosis of edwardsiellosis as well as for its possible use in epidemiological studies. methods and results:  et medium was evaluated in parallel with the commercial salmonella-shigella agar (ss), which ...201121554344
human immunodeficiency virus-associated gastrointestinal disease: common endoscopic biopsy diagnoses.the gastrointestinal (gi) tract is a major site of disease in hiv infection: almost half of hiv-infected patients present with gi symptoms, and almost all patients develop gi complications. gi symptoms such as anorexia, weight loss, dysphagia, odynophagia, abdominal pain, and diarrhea are frequent and usually nonspecific among these patients. endoscopy is the diagnostic test of choice for most hiv-associated gi diseases, as endoscopic and histopathologic evaluation can render diagnoses in patien ...201121559197
food-specific attribution of selected gastrointestinal illnesses: estimates from a canadian expert elicitation survey.abstract the study used a structured expert elicitation survey to derive estimates of food-specific attribution for nine illnesses caused by enteric pathogens in canada. it was based on a similar survey conducted in the united states and focused on campylobacter spp., escherichia coli o157:h7, listeria monocytogenes, nontyphoidal salmonella enterica, shigella spp., vibrio spp., yersinia enterocolitica, cryptosporidium parvum, and norwalk-like virus. a snowball approach was used to identify food ...201121561379
the decoupling between genetic structure and metabolic phenotypes in escherichia coli leads to continuous phenotypic diversity.to assess the extent of intra-species diversity and the links between phylogeny, lifestyle (habitat and pathogenicity) and phenotype, we assayed the growth yield on 95 carbon sources of 168 escherichia strains. we also correlated the growth capacities of 14 e. coli strains with the presence/absence of enzyme-coding genes. globally, we found that the genetic distance, based on multilocus sequence typing data, was a weak indicator of the metabolic phenotypic distance. besides, lifestyle and phylog ...201121569155
a tecpr1-dependent selective autophagy pathway targets bacterial pathogens.selective autophagy of bacterial pathogens represents a host innate immune mechanism. selective autophagy has been characterized on the basis of distinct cargo receptors but the mechanisms by which different cargo receptors are targeted for autophagic degradation remain unclear. in this study we identified a highly conserved tectonin domain-containing protein, tecpr1, as an atg5 binding partner that colocalized with atg5 at shigella-containing phagophores. tecpr1 activity is necessary for effici ...201121575909
a shigella boydii bacteriophage which resembles salmonella phage vii.abstract: background: lytic bacteriophages have been applied successfully to control the growth of various foodborne pathogens. sequencing of their genomes is considered as an important preliminary step to ensure their safety prior to food applications. results: the lytic bacteriophage, phisbom-ag3, targets the important foodborne pathogen, shigella. it is morphologically similar to phage vii of salmonella enterica serovar typhi and a series of phages of acinetobacter calcoaceticus and rhizobium ...201121595934
shigella sonnei vaccine candidates wrss2 and wrss3 are as immunogenic as wrss1, a clinically tested vaccine candidate, in a primate model of infection.shigella causes diarrhea and dysentery through contaminated food and water. shigella sonnei live vaccine candidates wrss2 and wrss3 are attenuated principally by the loss of virg(icsa) that prevents bacterial spread within the colonic epithelium. in this respect they are similar to the clinically tested vaccine candidate wrss1. however, wrss2 and wrss3 are further attenuated by loss of sena, senb and wrss3 also lacks msbb2. as previously shown in cell culture assays and in small animal models, t ...201121596086
transient suppression of shigella flexneri type 3 secretion by a protective o-antigen-specific monoclonal iga.abstract mucosal immunity to the enteric pathogen shigella flexneri is mediated by secretory iga (s-iga) antibodies directed against the o-antigen (o-ag) side chain of lipopolysaccharide. while secretory antibodies against the o-ag are known to prevent bacterial invasion of the intestinal epithelium, the mechanisms by which this occurs are not fully understood. in this study, we report that the binding of a murine monoclonal iga (igac5) to the o-ag of s. flexneri serotype 5a suppresses activity ...201121610121
dynamic aspects of antibody:oligosaccharide complexes characterized by molecular dynamics simulations and std-nmr.carbohydrates are likely to maintain significant conformational flexibility in antibody:carbohydrate complexes. as demonstrated herein for the protective monoclonal antibody f22-4 recognizing the shigella flexneri 2a o-antigen and numerous synthetic oligosaccharide fragments thereof, the combination of molecular dynamics simulations and nmr saturation transfer difference experiments, supported by physicochemical analysis, allows to determine the binding epitope and its various contributions to a ...201121610193
identification of small-molecule inhibitors of yersinia pestis type iii secretion system yscn atpase.yersinia pestis is a gram negative zoonotic pathogen responsible for causing bubonic and pneumonic plague in humans. the pathogen uses a type iii secretion system (t3ss) to deliver virulence factors directly from bacterium into host mammalian cells. the system contains a single atpase, yscn, necessary for delivery of virulence factors. in this work, we show that deletion of the catalytic domain of the yscn gene in y. pestis co92 attenuated the strain over three million-fold in the swiss-webster ...201121611119
bacterial load of fresh vegetables and their resistance to the currently used antibiotics in saudi arabia.abstract this study was carried out to describe the bacterial load and the occurrence of some disease-causing enteric bacteria on raw vegetables sold in saudi markets. the study further aimed to analyze antibiotic resistance rates, production of extended-spectrum beta lactamase, and plasmid carriage among bacterial population of raw vegetables. results revealed that none of them contained bacillus cereus, salmonella, and escherichia coli o157:h7. however, staphylococcus aureus and shigella were ...201121612423
a novel compound from the marine bacterium bacillus pumilus s6-15 inhibits biofilm formation in gram-positive and gram-negative species.biofilm formation is a critical problem in nosocomial infections and in the aquaculture industries and biofilms show high resistance to antibiotics. the aim of the present study was to reveal a novel anti-biofilm compound from marine bacteria against antibiotic resistant gram-positive and gram-negative biofilms. the bacterial extract (50 μg ml(-1)) of s6-01 (bacillus indicus = mtcc 5559) showed 80-90% biofilm inhibition against escherichia coli, shigella flexneri, proteus mirabilis and s6-15 (ba ...201121614700
prevalence of the plasmid mediated quinolone resistance determinants among clinical isolates of shigella sp. in andaman & nicobar islands, india.aims:  the present study was carried out to find the prevalence of various plasmid mediated quinolone resistant (pmqr) determinants among the quinolone resistant clinical isolates of shigella sp. from pediatric patients in andaman & nicobar islands. methods and results:  a total of 106 quinolone resistant shigella isolates obtained from pediatric patients during hospital based surveillance from january 2003 to june 2010 were screened for the presence of various pmqr determinants. out of 106 isol ...201121615433
complete (1)h and (13)c nmr chemical shift assignments of mono-, di-, and trisaccharides as basis for nmr chemical shift predictions of polysaccharides using the computer program casper.the computer program casper uses (1)h and (13)c nmr chemical shift data of mono- to trisaccharides for the prediction of chemical shifts of oligo- and polysaccharides. in order to improve the quality of these predictions the (1)h and (13)c, as well as (31)p when applicable, nmr chemical shifts of 30 mono-, di-, and trisaccharides were assigned. the reducing sugars gave two distinct sets of nmr resonances due to the α- and β-anomeric forms. in total 35 (1)h and (13)c nmr chemical shift data sets ...201121621752
fabrication of silver nanoparticles doped in the zeolite framework and antibacterial activity.using the chemical reduction method, silver nanoparticles (ag nps) were effectively synthesized into the zeolite framework in the absence of any heat treatment. zeolite, silver nitrate, and sodium borohydride were used as an inorganic solid support, a silver precursor, and a chemical reduction agent, respectively. silver ions were introduced into the porous zeolite lattice by an ion-exchange path. after the reduction process, ag nps formed in the zeolite framework, with a mean diameter of about ...201121383858
antigen-specific iga b memory cell responses to shigella antigens elicited in volunteers immunized with live attenuated shigella flexneri 2a oral vaccine candidates.we studied the induction of antigen-specific iga memory b cells (b(m)) in volunteers who received live attenuated shigella flexneri 2a vaccines. subjects ingested a single oral dose of 10(7), 10(8) or 10(9) cfu of s. flexneri 2a with deletions in guaba (cvd 1204) or in guaba, set and sen (cvd 1208). antigen-specific serum and stool antibody responses to lps and ipa b were measured on days 0, 7, 14, 28 and 42. iga b(m) cells specific to lps, ipa b and total iga were assessed on days 0 and 28. we ...201121388888
postinfective bile acid malabsorption: is this a long-term condition?postinfective bile acid malabsorption comprises a group of patients with a history of an episode of acute gastroenteritis triggering chronic diarrhoea. we identified these patients retrospectively from our medical records and assessed their long-term clinical course.201121389860
a candidate approach implicates the secreted salmonella effector protein spvb in p-body disassembly.p-bodies are dynamic aggregates of rna and proteins involved in several post-transcriptional regulation processes. p-bodies have been shown to play important roles in regulating viral infection, whereas their interplay with bacterial pathogens, specifically intracellular bacteria that extensively manipulate host cell pathways, remains unknown. here, we report that salmonella infection induces p-body disassembly in a cell type-specific manner, and independently of previously characterized pathway ...201121390246
structural elucidation of the o-antigen of the shigella flexneri provisional serotype 88-893: structural and serological similarities with s. flexneri provisional serotype y394 (1c).the structure of the repeating unit of the o-antigen polysaccharide from shigella flexneri provisional serotype 88-893 has been determined. (1)h and (13)c nmr spectroscopy as well as 2d nmr experiments were employed to elucidate the structure. the carbohydrate part of the hexasaccharide repeating unit is identical to the previously elucidated structure of the o-polysaccharide from s. flexneri prov. serotype y394. the o-antigen of s. flexneri prov. serotype 88-893 carries 0.7 mol o-acetyl group p ...201121392735
shigella flexneri type iii secreted effector ospf reveals new crosstalks of proinflammatory signaling pathways during bacterial infection.shigella flexneri type iii secreted effector ospf harbors a phosphothreonine lyase activity that irreversibly dephosphorylates map kinases (mapks) p38 and erk in infected epithelial cells and thereby, dampens innate immunity. whereas this activity has been well characterized, the impact of ospf on other host signaling pathways that control inflammation was unknown. here we report that ospf potentiates the activation of the mapk jnk and the transcription factor nf-?b during s. flexneri infection. ...201121402152
etiology of diarrhea in young children and patterns of antibiotic resistance in cambodia.little is known about diarrhea etiology and antibiotic resistance in developing countries where diarrhea is a major public health problem.201121412204
new insights into vinculin function and regulation.vinculin is a cytoplasmic actin-binding protein enriched in focal adhesions and adherens junctions that is essential for embryonic development. much is now known regarding the role of vinculin in governing cell-matrix adhesion. in the past decade that the crystal structure of vinculin and the molecular details for how vinculin regulates adhesion events have emerged. the recent data suggests a critical function for vinculin in regulating integrin clustering, force generation, and strength of adhe ...201121414589
antibacterial activity of the enniatin b, produced by fusarium tricinctum in liquid culture, and cytotoxic effects on caco-2 cells.the enniatins (ens) are bioactive compounds of hexadepsipeptidic structure produced by several strains of fusarium sp. the en b was purified from extracts of fusarium tricinctum growth on liquid culture of potato dextrose broth (pdb), using a semipreparative liquid chromatography (lc) followed by an analytical lc. the purity and the structure of the isolated compound were confirmed by the determination of the extinction coefficient and with electrospray ionization-mass spectrometry (esi-ms) stud ...201121417626
synthesis and in vitro microbiological evaluation of novel diethyl 6,6'-(1,4-phenylene)bis(4-aryl-2-oxo-cyclohex-3-enecarboxylates).novel bis cyclohexenone ester derivatives 14-19 were synthesized and characterized by their spectral data. in vitro microbiological evaluations were carried out for all the novel compounds 14-19 against clinically isolated bacterial and fungal strains. compounds 15, 16, 18 against staphylococcus aureus, 14, 15 against ß-haemolytic streptococcus, 15, 19 against micrococcus luteus, 17, 18 against salmonella typhii, 14, 17 against shigella flexneri, 15 against escherichia coli, 16 against pseudomon ...201121417963
evaluation of antidiarrheal and in vitro antiprotozoal activities of extracts of leaves of alocasia indica.alocasia indica schott (araceae) is used in several regions of india, especially in rural communities, by traditional medicine practitioners to treat diarrhea. however, no scientific data are available to justify the traditional potentials of the plant species in gastrointestinal disorders.201121428863
a comparison of disease caused by shigella and campylobacter species: 24 months community based surveillance in 4 slums of karachi, pakistan.despite the efforts of the international community diarrheal diseases still pose a major threat to children in children less than five years of age. bacterial diarrhea has also emerged as a public health concern due to the proliferation of drug resistant species in many parts of the world. there is a paucity of population-based data about the incidence of shigellosis and campylobacter infections in pakistan. we report country specific results for shigella diarrhea that were derived from a multic ...201121338955
interaction of the salmonella typhimurium effector protein sopb with host cell cdc42 is involved in intracellular replication.the phosphoinositide phosphatase sopb/sigd is a type iii secretion system effector that plays multiple roles in salmonella internalization and intracellular survival. we previously reported that sopb complexed with and inhibited the small gtpase cdc42 when expressed in a yeast model system, independently of its phosphatase activity. here we show that human cdc42, but not rac1, interacts with catalytically inactive sopb when coexpressed in saccharomyces cerevisiae. this interaction occurs with bo ...201121435037
multi-drug resistance and characteristic of integrons in shigella spp. isolated from china.to investigate the characteristic of integrons and the relationship between integrons and antimicrobial resistance in shigella spp.201121440840
quantification and evaluation of infectivity of shiga toxin-encoding bacteriophages in beef and salad.stx bacteriophages in 68 samples of beef and salad were quantified by real-time quantitative pcr (qpcr). stx phages from the samples were propagated in escherichia coli c600, e. coli o157:h7, and shigella strains and further quantified. fifty percent of the samples carried infectious stx phages that were isolated from plaques generated by lysis.201121441341
antimicrobial susceptibilities of enteric bacterial pathogens isolated in kathmandu, nepal, during 2002-2004.the prevalence and antimicrobial susceptibility patterns of the bacterial enteropathogens vibrio cholerae, salmonella species and shigella species were investigated.201121444984
antagonistic bacteria from live corals, tuticorin coastal waters, southeastern india.the objective of this study is to isolate and production of secondary metabolites with bioactive substances by coral reef (acropora formosa and favia palida) associated bacteria was carried out from the tuticorin coastal waters, southeastern india. the isolated coral associated bacteria were found to have an antagonistic effect against 10 human pathogens. the pathogens were escherichia coli, shigella dysentriae, staphylococcus epidermidis, s. aureus, klebsiella pneumoniae, pseudomonas aerogenosa ...201121454167
[invasive gastroenteritis, anything new?].invasive gastroenteritis is characterized by fever and inflammatory diarrhea and can be caused by nontyphoideal salmonella serotypes and shigella spp.-enteroinvasive escherichia coli (eiec), among other pathogens. this review describes emerging monophasic variants of salmonella enterica serotype 1,4,[5],12:i:- and provides an evolutionary consideration of shigella spp.-eiec as a single pathotype. in 1997, a monophasic variant of s. enterica serotype 1,4,[5],12:i:-, phage-type u302, multidrug res ...201121458713
vinculin activators target integrins from within the cell to increase melanoma sensitivity to chemotherapy.metastatic melanoma is an aggressive skin disease for which there are no effective therapies. emerging evidence indicates that melanomas can be sensitized to chemotherapy by increasing integrin function. current integrin therapies work by targeting the extracellular domain, resulting in complete gains or losses of integrin function that lead to mechanism-based toxicities. an attractive alternative approach is to target proteins, such as vinculin, that associate with the integrin cytoplasmic doma ...201121460181
autophagy and the cytoskeleton: new links revealed by intracellular pathogens.actin-based motility is used by various pathogens such as listeria and shigella for dissemination within cells: and tissues, yet host factors counteracting this process have not been identified. we have recently discovered that infected host cells can prevent actin-based motility of shigella by compartmentalizing bacteria inside 'septin cages,' revealing a novel mechanism of host defense that restricts dissemination. because bacterial proteins controlling actin-based motility also regulate the a ...201121464614
antimicrobial activity against shigella sonnei and probiotic properties of wild lactobacilli from fermented food.four lactobacilli strains (lactobacillus paracasei subp. paracasei m5-l, lactobacillus rhamnosus j10-l, lactobacillus casei q8-l and l. rhamnosus gg (lgg), were systematically assessed for the production of antimicrobial substances active towards shigella sonnei, escherichia coli and salmonella typhimurium. agar-well assay showed that the four lactobacilli strains displayed strong antibacterial activity towards s. sonnei. the nature of antimicrobial substances was also investigated and shown to ...201121466951
assessment of the antibacterial activity and the antidiarrheal function of flavonoids from bayberry fruit.chinese bayberry fruits are used as a folk medicine to cure diarrhea. however, the active compounds have not yet been reported. we found that bayberry fruit extract showed significant antibacterial activity against salmonella, listeria, and shigella, and the minimal inhibitory concentration (mic) ranged from 2.07 to 8.28 mg/ml. positive relationships were found between the antibacterial activity and the total polyphenol (r = 0.88) and flavonoid contents (r = 0.92) of samples using different extr ...201121469731
genetic diversity and antibiotic resistance in shigella dysenteriae and shigella boydii strains isolated from children aged <5 years in egypt.summarydiversity within shigella dysenteriae (n=40) and shigella boydii (n=30) isolates from children living in egypt aged <5 years was investigated. shigella-associated diarrhoea occurred mainly in summer months and in children aged <3 years, it commonly presented with vomiting and fever. serotypes 7 (30%), 2 (28%), and 3 (23%) accounted for most of s. dysenteriae isolates; 50% of s. boydii isolates were serotype 2. s. dysenteriae and s. boydii isolates were often resistant to ampicillin, chlor ...201121470441
new developments in traveler's diarrhea.traveler's diarrhea (td) is a crucial area for research, as it affects millions of tourists each year and creates a large economic burden. more than 60% of td cases are caused by a variety of bacterial enteropathogens: diarrhea-producing escherichia coli, shigella, campylobacter, salmonella, aeromonas, plesiomonas, and noncholera vibrios. noroviruses are also an important cause of morbidity among travelers. recent studies have identified host genetic risk factors associated with susceptibility t ...201121475415
behavior of salmonella typhimurium, staphylococcus aureus, listeria monocytogenes, and shigella flexneri and shigella sonnei during production of pulque, a traditional mexican beverage.pulque is a typical fermented alcoholic beverage of central mexico, produced from the nectar of maguey agave plants. production systems are largely artisanal, with inadequate hygiene conditions and exposure to multiple contamination sources. no data exist on pulque microbiological safety and the behavior of pathogenic microorganisms in agave nectar and pulque. an initial trial was done of the behavior of salmonella typhimurium, staphylococcus aureus, listeria monocytogenes, and shigella flexneri ...201121477472
dissemination of ndm-1 positive bacteria in the new delhi environment and its implications for human health: an environmental point prevalence study.not all patients infected with ndm-1-positive bacteria have a history of hospital admission in india, and extended-spectrum β-lactamases are known to be circulating in the indian community. we therefore measured the prevalence of the ndm-1 gene in drinking water and seepage samples in new delhi.201121478057
corn flake-like morphology of iron nanoparticles and its antibacterial property. 201121478648
an integrated approach for finding overlooked genes in shigella.the completion of numerous genome sequences introduced an era of whole-genome study. however, many genes are missed during genome annotation, including small rnas (srnas) and small open reading frames (sorfs). in order to improve genome annotation, we aimed to identify novel srnas and sorfs in shigella, the principal etiologic agents of bacillary dysentery.201121483688
phytochemical screening and antibacterial activities of vernonia ambigua, vernonia blumeoides and vernonia oocephala (asteraceae).some vernonia species (vernonia ambigua, vernonia blumeoides and vernonia oocephala) used in northern nigerian traditional medicine, were subjected to phytochemical screening using standard procedures. the antibacterial activity using the disc diffusion method as outlined by the nccls was carried out on klebsiella pneumoniae, streptococcus pyogenes, staphylococcus aureus, corynbacterium ulcerans, methicillin resistant staphylococcus aureus (mrsa), salmonella typhi, pseudomonas aeruginosa, shigel ...201121485703
outbreak of shigella sonnei infections in the orthodox jewish community of antwerp, belgium, april to august 2008.in the beginning of april 2008 three cases of shigella sonnei infection were identified among the orthodox jewish community of antwerp, belgium. we conducted a descriptive study and a household cohort study to identify potential risk factors. stool samples were cultured and antibiotic susceptibility of the isolates was determined. between april and august 2008, 42 cases were registered. all characterised isolates (n=20) shared an identical pulsed-field gel electrophoresis profile and were indist ...201121492526
zidovudine (azt) has a bactericidal effect on enterobacteria and induces genetic modifications in resistant strains.the spread of multiresistant bacteria increases the need for new antibiotics. the observation that some nucleoside analogues have antibacterial activity led us to further investigate the antimicrobial activity and resistance of zidovudine (azt). we determined the minimum inhibition concentration (mic), studied time-kill curves, induced resistant bacteria and sequenced the gene for thymidine kinase. we demonstrate that azt has a bactericidal effect on some enterobacteria. however, azt could induc ...201121494911
microbiological quality of grey-mullet roe.the greek grey-mullet roe is produced from the fully developed gonads of the female mullet (mugil cephalus) couth in lagoons during their reproductive migration. the traditional processing method of the roe includes, air drying, salting, shape formation and covering with multiple layers of natural beeswax for preservation and distribution. fish roe brands have been a staple in local diet and is increasingly becoming popular in the international market. as a ready-to-eat food it's microbial quali ...201121497664
a unique arabinose 5-phosphate isomerase found within a genomic island associated with the uropathogenicity of escherichia coli cft073.previous studies showed that deletion of genes c3405 to c3410 from pai-metv, a genomic island from escherichia coli cft073, results in a strain that fails to compete with wild-type cft073 after a transurethral cochallenge in mice and is deficient in the ability to independently colonize the mouse kidney. our analysis of c3405 to c3410 suggests that these genes constitute an operon with a role in the internalization and utilization of an unknown carbohydrate. this operon is not found in e. coli k ...201121498648
shigella targets t cells.using a syringe-like device, shigella delivers an array of virulence factors into host cells to facilitate bacterial colonization and disable the host's innate immune defense. in this issue of cell host & microbe, konradt and colleagues (konradt et al., 2011) show that shigella also subverts adaptive immunity by targeting t cells through a mechanism involving pip(2) breakdown.201121501822
the shigella flexneri type three secretion system effector ipgd inhibits t cell migration by manipulating host phosphoinositide metabolism.shigella, the gram-negative enteroinvasive bacterium that causes shigellosis, relies on its type iii secretion system (ttss) and injected effectors to modulate host cell functions. however, consequences of the interaction between shigella and lymphocytes have not been investigated. we show that shigella invades activated human cd4(+) t lymphocytes. invasion requires a functional ttss and results in inhibition of chemokine-induced t cell migration, an effect mediated by the ttss effector ipgd, a ...201121501826
enteric virulence associated protein vapc inhibits translation by cleavage of initiator trna.eukaryotic pin (pilt n-terminal) domain proteins are ribonucleases involved in quality control, metabolism and maturation of mrna and rrna. the majority of prokaryotic pin-domain proteins are encoded by the abundant vapbc toxin-antitoxin loci and inhibit translation by an unknown mechanism. here we show that enteric vapcs are site-specific endonucleases that cleave trna(fmet) in the anticodon stem-loop between nucleotides +38 and +39 in vivo and in vitro. consistently, vapc inhibited translation ...201121502523
evaluation of low-copy genetic targets for waterborne bacterial pathogen detection via qpcr.recent developments in water quality research have highlighted difficulties in accurately predicting the incidence of pathogens within freshwater based on the viability, culturability and metabolic activity of indicator organisms. qpcr-driven assays are candidates to replace standard culture-based methods, however, protocols suitable for routine use have yet to be sufficiently validated. the objective of this study was to evaluate five oligonucleotide primers sets (etir, sinv, exot, vs1 and ipah ...201121514618
functional domains and motifs of bacterial type iii effector proteins and their roles in infection.a key feature of the virulence of many bacterial pathogens is the ability to deliver effector proteins into eukaryotic cells via a dedicated type three secretion system (t3ss). many bacterial pathogens, including species of chlamydia, xanthomonas, pseudomonas, ralstonia, shigella, salmonella, escherichia and yersinia, depend on the t3ss to cause disease. t3ss effectors constitute a large and diverse group of virulence proteins that mimic eukaryotic proteins in structure and function. a salient f ...201121517912
a novel vinculin binding site of the ipaa invasin of shigella.internalization of shigella into host epithelial cells, where the bacteria replicates and spreads to neighboring cells, requires a type 3 secretion system (t3ss) effector coined ipaa. ipaa binds directly to and activates the cytoskeletal protein vinculin after injection in the host cell cytosol and heretofore this was thought to be directed by two amphipathic α-helical vinculin binding sites (vbs) found in the c-terminal tail domain of ipaa. here we report a third vbs, ipaa-vbs3, that is located ...201121525010
synthesis, antibacterial activity and quantum-chemical studies of novel 2-arylidenehydrazinyl-4-arylthiazole analogues.a new series of 2-arylidenehydrazinyl-4-arylthiazole derivatives (2a-k) was designed and synthesized through a rapid, simple, and efficient methodology in excellent isolated yield. these compounds were screened for in vitro antimicrobial activities against eight bacteria, e.g. bacillus cereus, staphylococcus aureus, bacillus subtilis, bacillus megaterium, pseudomonas aeruginosa, shigella dysenteriae, salmonella typhi, escherichia coli, and three fungi e.g. aspergillus oryzae, candida albicans, a ...201121532194
synthesis, characterization and in vitro antimicrobial evaluation of new compounds incorporating oxindole nucleus.new compounds incorporating with the oxindole nucleus were synthesized via the reaction of substituted isatins [5-methyl-, 5-chloro- and 1-hydroxymethyl isatins] with different nucleophiles. the structures of the newly compounds were elucidated on the basis of ftir, (1)h nmr, (13)cmr spectral data, gc/ms and chemical analysis. investigation of antimicrobial activity of the new compounds was evaluated using broth dilution technique in terms of minimal inhibitory concentration (mic) count against ...201121534861
synthesis, characterization and biological studies of sulfonamide schiff's bases and some of their metal derivatives.a new series of schiff base ligands derived from sulfonamide and their metal(ii) complexes [cobalt(ii), copper(ii), nickel(ii) and zinc(ii)] have been synthesized and characterized. the nature of bonding and structure of all the synthesized compounds has been explored by physical, analytical and spectral data of the ligands and their metal(ii) complexes. the authors suggest that all the prepared complexes possess an octahedral geometry. the ligands and metal(ii) complexes have been screened for ...201121534864
synthesis, characterization and biological properties of thienyl derived triazole schiff bases and their oxovanadium(iv) complexes.a new series of biologically active thienyl derived triazole schiff bases and their oxovanadium(iv) complexes have been synthesized and characterized on the basis of physical (m.p., magnetic susceptibility and conductivity), spectral (ir, (1)h and (13)c nmr, electronic and mass spectrometry) and microanalytical data. all the schiff base ligands and their oxovanadium(iv) complexes have been subjected to in vitro antibacterial activity against four gram-negative (escherichia coli, shigella flexner ...201121635212
structure-guided investigation of lipopolysaccharide o-antigen chain length regulators reveals regions critical for modal length control.the o-antigen component of the lipopolysaccharide (lps) represents a population of polysaccharide molecules with a non-random (modal) chain length distribution. the number of the repeat o-units in each individual o-antigen polymer depends on the wzz chain-length regulator, an inner membrane protein belonging to the polysaccharide co-polymerase (pcps) family. different wzz proteins confer vastly different ranges of modal lengths (4 to >100 repeat units) despite having remarkably conserved structu ...201121642455
production of bioactive sheep β-defensin-1 in pichia pastoris.previous research has shown that sheep β-defensin-1 (sbd-1), a small cationic peptide with a broad range of antimicrobial activities, could inhibit the growth of both gram-positive and gram-negative bacteria as well as that of fungi. in order to increase the yield of current ovine defensin purification methods, mature sbd-1 (msbd-1) was added with a 6-his tag on the c-terminus (msbd-1-t) and expressed in pichia pastoris in the presented work. the msbd-1 and msbd-1-t were expressed in the pichia ...201121643707
p62 and ndp52 target intracytosolic shigella and listeria to different autophagy pathways.autophagy is an important mechanism of innate immune defense. we have recently shown that autophagy components are recruited with septins, a new and increasingly characterized cytoskeleton component, to intracytosolic shigella that have started to polymerize actin. on the other hand, intracytosolic listeria avoids autophagy recognition by expressing acta, a bacterial effector required for actin polymerization. here we exploit shigella and listeria as intracytosolic tools to characterize differen ...201121646350
bacteriophage-encoding cytolethal distending toxin type-v gene induced from non-clinical escherichia coli isolates.cytolethal distending toxin (cdt) is produced by a variety of pathogenic bacteria, including pathogenic serotypes of shiga toxin-producing escherichia coli (stec). the cdt family comprises five variants (cdt-i to cdt-v) encoded by three genes located within the chromosome, plasmids or, in the case of cdt-i, within bacteriophages. in this study we evaluated the occurrence of cdt in a collection of 140 environmental stec isolates. cdt was detected in 12.1% of strains, of which five strains carried ...201121646456
development of multiplex loop-mediated isothermal amplification-rflp (mlamp-rflp) to detect salmonella spp. and shigella spp. in milk.a multiplex loop-mediated isothermal amplification-rflp (mlamp-rflp) was developed and validated for simultaneous detection of salmonella strains and shigella strains in milk. in this system, two sets of lamp primers were designed to specifically target inva of salmonella spp. and ipah of shigella spp. under isothermal conditions at 63 °c, ladder pattern of dna bands could be amplified within 60 min in the presence of genomic dnas of salmonella strains and shigella strains, which could be distin ...201121652102
gisul2, a genomic island carrying the sul2 sulphonamide resistance gene and the small mobile element cr2 found in the enterobacter cloacae subspecies cloacae type strain atcc 13047 from 1890, shigella flexneri atcc 700930 from 1954 and acinetobacter baumannii atcc 17978 from 1951. 201121653606
a 9-year study of shigellosis in northeast malaysia: antimicrobial susceptibility and shifting species dominance.aims: in malaysia, shigella spp. is the third most common bacterial agent responsible for childhood diarrhoea. this study was conducted to determine the prevalence and antimicrobial susceptibility patterns of shigella spp. isolated from patients admitted to the hospital universiti sains malaysia from january 2001 to december 2009. subjects and methods: a hospital-based retrospective study was used. stool samples from patients were cultured using a standard culture method. shigella spp. isolates ...201121654922
modulation of connexin signaling by bacterial pathogens and their toxins.inherent to their pivotal tasks in the maintenance of cellular homeostasis, gap junctions, connexin hemichannels, and pannexin hemichannels are frequently involved in the dysregulation of this critical balance. the present paper specifically focuses on their roles in bacterial infection and disease. in particular, the reported biological outcome of clinically important bacteria including escherichia coli, shigella flexneri, yersinia enterocolitica, helicobacter pylori, bordetella pertussis, aggr ...201121656255
genetic characteristics and changing antimicrobial resistance among shigella spp isolated from hospitalized diarrhoeal patients in kolkata, india.to study the prevalence pattern and trends in the phenotypic and genetic characteristics of shigellae, we tested 212 isolates isolated from diarrhoeal patients admitted at the infectious diseases hospital, kolkata, india from november 2007 to october 2009. prevalence of shigella spp was more in more than 5 years age group (69%) than the children >5 years age group (31%). serotypes 2a, 3a and untypable isolates of the subtype s. flexneri were frequently detected. increase in the isolation of s. s ...201121659504
vital signs: incidence and trends of infection with pathogens transmitted commonly through food--foodborne diseases active surveillance network, 10 u.s. sites, 1996-2010.in the united states, contaminated food causes approximately 1,000 reported disease outbreaks and an estimated 48 million illnesses, 128,000201121659984
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