Publications

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functional characterization of the shigella dysenteriae heme abc transporter.the heme atp binding cassette (abc) transporter, shuuv, of shigella dysenteriae has been incorporated into proteoliposomes. functional characterization of shuuv revealed that atp hydrolysis and transport of heme from the periplasmic binding protein, shut, to the cytoplasmic binding protein, shus, are coupled. site-directed mutagenesis of shut residues proposed to be required for stabilization of the complex abolished heme transport. furthermore, residues his-252 and his-262, located in the trans ...200818616281
structures of synthetic o-antigen fragments from serotype 2a shigella flexneri in complex with a protective monoclonal antibody.the anti-lps igg mab f22-4, raised against shigella flexneri serotype 2a bacteria, protects against homologous, but not heterologous, challenge in an experimental animal model. we report the crystal structures of complexes formed between fab f22-4 and two synthetic oligosaccharides, a decasaccharide and a pentadecasaccharide that were previously shown to be both immunogenic and antigenic mimics of the s. flexneri serotype 2a o-antigen. f22-4 binds to an epitope contained within two consecutive 2 ...200818621718
first italian case of cyclosporiasis in an immunocompetent woman: local acquired infection.cyclospora cayetanensis is a coccidian agent of chronic diarrhea in humans with a worldwide distribution. we report the first documented case of acquired cyclosporiasis in italy. the patient was an immunocompetent woman with no recent history of travel outside the country. microscopy detected cyclospora oocysts in a feces sample. pcr detected the pathogen in a second sample, which had tested negative by microscopy. the patient was investigated to detect other microorganisms in feces, such as sal ...200818623995
[detection of enteric pathogenic bacteria from surface waters by quantitative polymerase chain reaction (qpcr)].a rapid quantitative polymerase chain reaction (qpcr) analysis method with universal primers was developed to detect cell densities of the enteric pathogenic bacteria from 5 surface water of xi'an city for 4 months continuously. and the detection results by qpcr method were compared with counts of coliforms colony-forming units (cfu) determined by membrane filter (mf) analysis. the results showed that qpcr method had an estimated 94% confidence, and detection limit was 2.7 escherichia coli cells ...200818624175
overview of the inactivation by 254 nm ultraviolet radiation of bacteria with particular relevance to biodefense.our goal was to ultimately predict the sensitivity of untested bacteria (including those of biodefense interest) to ultraviolet (uv) radiation. in this study, we present an overview and analysis of the relevant 254 nm data previously reported and available in the literature. the amount of variability in this data prevented us from determining an "average" response for any bacterium. therefore, we developed particular selection criteria to include the data in our analysis and suggested future gui ...200818627518
is irritable bowel syndrome an inflammatory disorder?histopathologic data demonstrate low-grade mucosal inflammation in a subset of patients with irritable bowel syndrome (ibs). this inflammatory infiltrate is mainly represented by increased numbers of t lymphocytes and mast cells lying in the lamina propria. the close apposition of immunocytes to gut nerves supplying the mucosa provides a basis for neuroimmune cross-talk, which may explain gut sensorimotor dysfunction and related symptoms in patients with ibs. a previous gastroenteritis (due to c ...200818627650
a single-tube screen for salmonella and shigella.salmonella and shigella species are routinely sought in stool specimens submitted for culture. it is a common practice to screen lactose-negative colonies by using triple sugar iron agar, lysine iron agar, and christensen urea agar to determine if further identification is necessary. we designed and evaluated a novel combination of media, which are layered in a single tube, for screening isolates suspected to possibly represent salmonella or shigella. we tested this media combination with 106 sa ...200818628099
haemolytic uraemic syndrome in children admitted to a rural district hospital in kenya.we studied children admitted to kilifi district hospital, kenya, between 1997 and 2005 with haemolytic uraemic syndrome (hus) and reviewed their records in order to determine the clinical features and outcomes of the disease. thirty-one children fulfilled the criteria: 21 (68%) had diarrhoea-associated hus (d + hus), the remainder did not (d-hus); five had involvement of the central nervous system. those with d-hus had lower haemoglobin and platelet counts when compared with those with d + hus. ...200818628547
[investigation on species composition of cockroaches and bacteria-carrying on their bodies in five cities of hainan]."za-type" cages were used to capture cockroaches in 267 sites of 5 cities in hainan. species were identified and bacteria were isolated by routine method. 441 cockroaches were collected and identified as five species belonging to two genera, 75.3% being periplaneta americana. more cockroaches were found in sewerage. bacteria were detected from 82.4% of cockroaches, including escherichia coli, pseudomonas aeruginosa, salmonella sp, staphylococcus aureus, shigella sp, bacillus proteus and sort of ...200818637594
crystal structure of a glutamate/aspartate binding protein complexed with a glutamate molecule: structural basis of ligand specificity at atomic resolution.the crystal structure of a periplasmic l-aspartate/l-glutamate binding protein (debp) from shigella flexneri complexed with an l-glutamate molecule has been determined and refined to an atomic resolution of 1.0 a. there are two debp molecules in the asymmetric unit. the refined model contains 4462 non-hydrogen protein atoms, 730 water molecules, 2 bound glutamate molecules, and 2 tris molecules from the buffer used in crystallization. the final r(cryst) and r(free) factors are 13.61% and 16.89%, ...200818640128
the epidemiological and clinical characteristics and nutritional development of infants with acute diarrhoea, in north-eastern brazil.in order to assess the epidemiological and clinical characteristics and changing nutritional status of infants suffering from acute diarrhoea, 103 infants with such diarrhoea and the same number of age-matched controls were investigated at the universidade federal do rio grande do norte's paediatric hospital, in north-eastern brazil. each child with diarrhoea was given oral rehydration or, in the severe cases, intravenous rehydration. each subject was checked for enteropathogens and his or her w ...200818510816
a hierarchical model for studying risk factors for childhood diarrhoea: a case-control study in a middle-income country.to identify factors associated with diarrhoea occurrence in children in a city in a middle-income country, with high access to water and sanitation.200818515864
viral, bacterial and parasitic etiology of pediatric diarrhea in gaza, palestine.to determine the etiology of acute diarrhea in palestinian children under 5 years of age and to improve knowledge of the etiology of gastrointestinal pathogens using traditional and molecular diagnostic techniques.200818523397
the serine protease motif of pic mediates a dose-dependent mucolytic activity after binding to sugar constituents of the mucin substrate.the pic gene is harbored on the chromosomes of three important pathogens: enteroaggregative escherichia coli (eaec), uropathogenic e. coli (upec), and shigella flexneri. since pic is secreted into the intestinal lumen during eaec infection, we sought to identify intestinal-mucosal substrates for pic. pic did not damage epithelial cells, cleave fodrin, or degrade host defense proteins embedded in the mucus layer (siga, lactoferrin and lysozyme). however, by using a solid-phase assay to evaluate t ...200818538533
prevalence of different virulence factors and biofilm production in enteroaggregative escherichia coli isolates causing diarrhea in children in ifakara (tanzania).this study investigated the prevalence of 19 virulence factors and biofilm production in 86 eaec isolates causing diarrhea in children less than 5 years of age from ifakara, tanzania. virulence factors were detected by pcr, whereas biofilm production was determined using a microtiter plate assay. no virulence factor, with the exception of the aat gene used to identify eaec, was detected in 11/86 isolates (12.8%). the most frequently detected virulence factor was the aggr gene in 53 (61.6%) eaec, ...200818541781
crystal structure of escherichia coli phage hk620 tailspike: podoviral tailspike endoglycosidase modules are evolutionarily related.bacteriophage hk620 infects escherichia coli h and is closely related to shigella phage sf6 and salmonella phage p22. all three podoviridae recognize and cleave their respective host cell receptor polysaccharide by homotrimeric tailspike proteins. the three proteins exhibit high sequence identity in the 110 residues of their n-terminal particle-binding domains, but no apparent sequence similarity in their major, receptor-binding parts. we have biochemically characterized the receptor-binding par ...200818547389
shigella bacteraemia over a decade in soweto, south africa.shigella infection rarely penetrates beyond the intestinal mucosa to cause bacteraemia. aids patients may be at increased risk. we investigated shigella bacteraemia rates over a decade in a south african population with a high hiv prevalence and analysed presentation and outcome. a retrospective cohort analysis was performed for hospitalized patients for 2003-2006. the rates were compared to those for 1996-1998. adult medical rates decreased from 0.195/1000 in 1996-1998 to 0.087/1000 admissions ...200818550134
[shigella spp. infections in getafe hospital between 2001 and 2006].shigella spp. is a bacterium that frequently causes diarrhoea in underdeveloped countries, but not so much in spain, where it has been published that its incidence has decreased in the last few years.200818559201
a food borne outbreak of gastroenteritis due to shigella and possibly salmonella in a school.on august 5, 2005, a private hospital reported a large number of students with gastrointestinal illness from the same school in bangkok, thailand. the bureau of epidemiology along with the bangkok metropolitan administration investigated this outbreak, to determine risk factors, identify the source of infection and possible causative organism, and recommend prevention and control strategies. a case was defined as a person who was studying or working at school a and who developed abdominal pain, ...200818564716
reactive arthritis with conjunctivitis, urethritis and diarrhea in a child: immunological study of potential bacterial trigger. 200818565268
description of an unusual class 2 integron in shigella sonnei isolates in senegal (sub-saharan africa). 200818565971
molecular characterization of multidrug-resistant shigella species isolated from epidemic and endemic cases of shigellosis in india.shigella species represent one of the growing numbers of antimicrobial-resistant bacteria in developing countries. fluoroquinolone-resistant strains of shigella dysenteriae type 1 and shigella flexneri type 2a emerged in india during 2002 and 2003, respectively. sixty strains of shigella from different parts of india were analysed for antimicrobial susceptibility, the presence of the qnr plasmid, mutations in the quinolone resistance determining regions (qrdrs), fluoroquinolone accumulation, and ...200818566144
design, synthesis, characterization, antibacterial and antifungal activities of a novel class of 5,7-diaryl-4,4-dimethyl-4,5,6,7-tetrahydropyridino[3,4-d]-1,2,3-selenadiazoles.compound 26 is more potent against escherichia coli. and 24 is more active against staphylococcus aureus, beta-heamolytic streptococcus, vibreo cholerae, salmonella typhii, and shigella flexneri than the standard drug ciprofloxacin. moreover, of all the compounds tested, 26 is more effective against aspergillus flavus and mucor, than the standard drug fluconazole.200818569338
bacterial triggers and autoimmune rheumatic diseases.autoimmune rheumatic diseases are generally considered as a multifactorial aetiology, mainly genetic susceptibility combined with environmental triggers of which bacteria are considered one of the most prominent. among the rheumatic diseases where bacterial agents are more clearly involved as triggers are: reactive arthritis (rea), rheumatic fever (rf) and lyme disease. the role of bacterial infections in inducing other seronegative spondyloarthritis and antiphospholipid antibody syndrome has be ...200818570749
combined physico-chemical treatments based on enterocin as-48 for inactivation of gram-negative bacteria in soybean sprouts.enterocin as-48 was tested for decontamination of soybean sprouts against gram-negative bacteria. although treatment with bacteriocin alone had no effect on salmonella enterica, a synergistic antimicrobial effect was detected at ph 9.0 and in combination with moderate heat treatment. greatest inactivation was achieved for sprouts heated for 5 min at 65 degrees c in an alkaline (ph 9.0) enterocin as-48 solution of 25 microg/ml. bactericidal activity against s. enterica increased greatly when ente ...200818577412
vibrio cholerae vcib promotes iron uptake via ferrous iron transporters.vibrio cholerae uses a variety of strategies for obtaining iron in its diverse environments. in this study we report the identification of a novel iron utilization protein in v. cholerae, vcib. the vcib gene and its linked gene, vcia, were isolated in a screen for v. cholerae genes that permitted growth of an escherichia coli siderophore mutant in low-iron medium. the vciab operon encodes a predicted tonb-dependent outer membrane receptor, vcia, and a putative inner membrane protein, vcib. vcib, ...200818586940
anti-infectious effect of s-benzylisothiourea compound a22, which inhibits the actin-like protein, mreb, in shigella flexneri.s-benzylisothiourea compound a22 induces coccoid forms in escherichia coli by inhibiting the function of the actin-like cytoskeletal protein, mreb. the minimum inhibitory concentration of a22 and the minimum concentration to induce coccoid forms for various pathogenic bacteria were determined. at 10 microg/ml, a22 induced coccoid forms in shigella flexneri but did not inhibit the growth. no alteration of coccoid forms in the gram-positive bacteria and anaerobic bacteria tested were observed foll ...200818591769
[epidemic strains of different plasmidovars of bacteria from shigella genus].plasmid analysis of 46 strains of shigella species confirmed the view about heterogeneity and variability of plasmids composition in these microorganisms. on the other hand,the presence of low-molecular, multiplicated extrachromosomal replicons, which were stable, was shown. using them, it was possible to divide the shigella isolates into two major plasmidovars, characterize them according to repertoire of the most stable plasmids and determine epidemically significant variants during sporadic a ...200818595459
[sonnei dysentery--the next in stage of the shigelloses' evolution]. 200818595478
[electrical resistance of bacterial culture suspension as indicator of epidemic and sporadic variants of shigella].for the first time method of measurement of electric resistance of bacterial suspension was used for differentiation of "epidemic" and "sporadic" (further used without quotes) variants of shigella species. study of 40 strains of s. flexneri and s. sonnei revealed significant differences in electric resistance of cultures isolated during epidemic outbreaks after the growth during 1 or 6 hours - 18.1+/-8.3 kohm and 84.6+/-7.8 kohm respectively (increase in 4.9-fold; p<0.01), while non significant ...200818597992
cold shock exoribonuclease r (vacb) is involved in aeromonas hydrophila pathogenesis.in this study, we cloned and sequenced a virulence-associated gene (vacb) from a clinical isolate ssu of aeromonas hydrophila. we identified this gene based on our recently annotated genome sequence of the environmental isolate atcc 7966(t) of a. hydrophila and the vacb gene of shigella flexneri. the a. hydrophila vacb protein contained 798 amino acid residues, had a molecular mass of 90.5 kda, and exhibited an exoribonuclease (rnase r) activity. the rnase r of a. hydrophila was a cold-shock pro ...200818344363
maturation of paneth cells induces the refractory state of newborn mice to shigella infection.the intestinal tract of adult mice is naturally resistant to infection by shigella, the causative agent of bacillary dysentery in humans. conversely, newborn mice are highly susceptible to intragastric shigella infection and develop inflammatory lesions of the jejunal mucosa, very similar to those observed in the colon of dysenteric patients. however, the susceptibility period is short and one week after birth, animals have acquired a status of resistance characteristic of adult animals. to iden ...200818354217
high rate of resistance to locally used antibiotics among enteric bacteria from children in northern ghana.information on antimicrobial susceptibility of bacterial pathogens is scarce in resource-poor settings. we determined the susceptibility of bacterial enteric pathogens and faecal escherichia coli isolates obtained from children in urban tamale, northern ghana, to antibiotics widely used in the that area [ampicillin or amoxicillin, trimethoprim/sulfamethoxazole (sxt) and chloramphenicol] and to alternative drugs.200818356156
differential expression of ompc and ompf in multidrug-resistant shigella dysenteriae and shigella flexneri by aqueous extract of aegle marmelos, altering its susceptibility toward beta-lactam antibiotics.steadily increasing resistance among shigella to beta-lactams, aminoglycosides, and tetracycline has compromised the utility of these commonly used antimicrobial agents. also, undesirable side effects of certain antibiotics have triggered immense interest in search of alternative therapies using medicinal plants. one such medicinal plant used since ancient times to cure diarrhea is aegle marmelos. the present study exemplifies the susceptibility of beta-lactam-resistant shigella dysenteriae and ...200818358664
differential regulation by magnesium of the two msbb paralogs of shigella flexneri.shigella flexneri, a gram-negative enteric pathogen, is unusual in that it contains two nonredundant paralogous genes that encode the myristoyl transferase msbb (lpxm) that catalyzes the final step in the synthesis of the lipid a moiety of lipopolysaccharide. msbb1 is encoded on the chromosome, and msbb2 is encoded on the large virulence plasmid present in all pathogenic shigellae. we demonstrate that myristoyl transferase activity due to msbb2 is detected in limited magnesium medium, but not in ...200818359815
ctx-m-3 type beta-lactamase producing shigella sonnei isolates from pediatric bacillary dysentery cases.in this study, 153 clinical isolates of shigella were screened for extended-spectrum beta-lactamase (esbl) production by double-disk synergy test. after being confirmed by the combined disk-test and inhibitor-combined e-test strips, all positive isolates were tested for the bla gene by pcr and the enzymes by isoelectric focusing. dna sequencing of pcr products revealed that five shigella sonnei isolates had ctx-m-3 type esbl enzymes. all of them were resistant to ampicillin, sulfamethoxazole and ...200818362404
[antigenic polysaccharides of bacteria: 40. the structures of o-specific polysaccharides from shigella dysenteriae types 3 and 9 and s. boydii type 4 revised by nmr spectroscopy].the reported structures of o-specific polysaccharides from three standard strains of shigella bacteria were corrected by modern nmr techniques. the revisions concerned the configuration of the o-glycoside linkage (s. dysenteriae type 3, structure 1), the positions of monosaccharide residue glycosylation and acetylation by pyruvic acid (s. dysenteriae type 9, structure 2), and the attachment position of the side monosaccharide chain (s. boydii type 4, structure 3) [struxture in text].200818365747
contamination of a blood culture with shigella sonnei. 200818371521
analysis of rho-gtpase mimicry by a family of bacterial type iii effector proteins.microbial pathogens may hijack the actin cytoskeleton machinery to facilitate actin-based motility, cellular invasion, and intracellular trafficking through the endocytic pathway. of particular interest has been a large class of virulence factors collectively termed the type iii "effector" proteins. following contact with a eukaryotic cell, gram-negative bacterial pathogens employ a dedicated protein secretion apparatus termed type iii to translocate effector proteins into the cellular cytoplasm ...200818374161
coiled-coil regions play a role in the function of the shigella flexneri o-antigen chain length regulator wzzphs2.regulation of the length of the o-antigen (oag) chain attached to lps in shigella flexneri is important for virulence and is dependent on the inner-membrane protein wzz. a lack of high-resolution structural data for wzz has hampered efforts so far to correlate mutations affecting function of wzz with structure and describe a mechanism for chain length regulation. here we have used secondary structure prediction to show that the periplasmic domain of the wzz(phs2) protein has three regions of sig ...200818375803
ospf directly attenuates the activity of extracellular signal-regulated kinase during invasion by shigella flexneri in human dendritic cells.shigella spp., gram-negative pathogenic bacteria, deliver various effector molecules into the host cell cytoplasm through their type iii secretion system to facilitate their invasive process and control the host innate immune responses. although the function of these effectors is well characterized in epithelial cells during shigella infection, it has not been elucidated in the dendritic cell (dc), a major antigen presenting cell playing an important role in the initiation of immune responses. i ...200818378312
insecticidal properties and microbial contaminants in a spodoptera exigua multiple nucleopolyhedrovirus (baculoviridae) formulation stored at different temperatures.the spodoptera exigua (hübner) multiple nucleopolyhedrovirus (semnpv) is currently being tested as a biological insecticide for use in greenhouse crops in southern spain. we performed a study in which semipurified semnpv occlusion bodies (obs) were formulated in phosphate-buffered saline, ph 6.5, with 5% (vol:vol) glycerol and 0.15% (wt:vol) sorbic acid, and they were stored at -20, 4, or 25 degrees c during 18 mo. initial aerobic counts (+/-se) averaged 1.4 (+/-0.17) x 10(7) colony-forming unit ...200818330114
subversion of actin dynamics by espm effectors of attaching and effacing bacterial pathogens.rho gtpases are common targets of bacterial toxins and type iii secretion system effectors. ipgb1 and ipgb2 of shigella and map of enteropathogenic (epec) and enterohemorrhagic (ehec) escherichia coli were recently grouped together on the basis that they share a conserved wxxxe motif. in this study, we characterized six wxxxe effectors from attaching and effacing pathogens: trca and espm1 of epec strain b171, espm1 and espm2 of ehec strain sakai and espm2 and espm3 of citrobacter rodentium. we s ...200818331467
prevalence of gastrointestinal bacterial pathogens in a population of zoo animals.faecal prevalence of gastrointestinal bacterial pathogens, including campylobacter, escherichia coli o157:h7, salmonella, shigella, yersinia, as well as arcobacter, were examined in 317 faecal specimens from 44 animal species in belfast zoological gardens, during july-september 2006. thermophilic campylobacters including campylobacter jejuni, campylobacter coli and campylobacter lari, were the most frequently isolated pathogens, where members of this genus were isolated from 11 animal species (1 ...200818331520
delivery of biologically active anti-inflammatory cytokines il-10 and il-1ra in vivo by the shigella type iii secretion apparatus.pathogenicity of many gram-negative bacteria relies on a type iii secretion (t3s) apparatus, which is used for delivery of bacterial effectors into the host cell cytoplasm allowing the bacteria to manipulate host cell cytoskeleton network as well as to interfere with intracellular signaling pathways. in this study, we investigated the potential of the shigella flexneri t3sa as an in vivo delivery system for biologically active molecules such as cytokines. the anti-inflammatory cytokines il-10 an ...200818322242
impact of infections and normal flora in nonhuman primates on drug development.preclinical safety studies that are required for the marketing approval of a pharmaceutical include single and repeat dose studies in rodent and nonrodent species. the use of nonhuman primates (nhps), primarily macaques, as the nonrodent species has increased in recent years, in part due to the increase in development of biopharmaceuticals and immunomodulatory agents. depending on the source of the macaques, they may vary in genetic background, normal flora, and/or the incidence of preexisting p ...200818323580
pyrosequencing analysis of the gyrb gene to differentiate bacteria responsible for diarrheal diseases.pathogens causing acute diarrhea include a large variety of species from enterobacteriaceae and vibrionaceae. a method based on pyrosequencing was used here to differentiate bacteria commonly associated with diarrhea in china; the method is targeted to a partial amplicon of the gyrb gene, which encodes the b subunit of dna gyrase. twenty-eight specific polymorphic positions were identified from sequence alignment of a large sequence dataset and targeted using 17 sequencing primers. of 95 isolate ...200818324428
timeliness of enteric disease surveillance in 6 us states.we reviewed timeline information for a sample of salmonella spp., shigella spp., campylobacter spp., and escherichia coli o157:h7 cases and all confirmed foodborne outbreaks reported in 6 states during 2002. increasing the timeliness of case follow-up, molecular subtyping, and linkage of results are critical to reducing delays in the investigation of foodborne outbreaks.200818258128
[shigella spp infections in children living in the metropolitan region, chile, during summer of 2004-2005].shigella spp is a frequent cause of diarrhea in children. antimicrobials decrease the duration of diarrhea and pathogen excretion. however, the increasing resistance limits their therapeutic value.200818259649
[shigellosis outbreak with 146 cases related to a fair].on september 3, 2005, the ciudad real public health service (spain) received a report of 20 cases of gastroenteritis in the municipality of daimiel. we conducted an investigation to determine the cause or causes of the outbreak and to implement control measures. most of the cases involved young people who visited the municipality's fair.200818261440
extracellular-loop peptide antibodies reveal a predominant hemichannel organization of connexins in polarized intestinal cells.shigella, the causative agent of bacillary dysentery, invades colonic epithelial cells to elicit an intense inflammatory reaction leading to destruction of the mucosa. atp-dependent paracrine signalling induced by connexin (cx) hemichannel opening was previously shown to favor shigella flexneri invasion and dissemination in transfectants of hela cells [g. tran van nhieu, c. clair, r. bruzzone, m. mesnil, p. sansonetti and l. combettes. (2003). connexin-dependent intercellular communication incre ...200818267319
retrograde traffic in the biosynthetic-secretory route.in the biosynthetic-secretory route from the rough endoplasmic reticulum, across the pre-golgi intermediate compartments, the golgi apparatus stacks, trans golgi network, and post-golgi organelles, anterograde transport is accompanied and counterbalanced by retrograde traffic of both membranes and contents. in the physiologic dynamics of cells, retrograde flow is necessary for retrieval of molecules that escaped from their compartments of function, for keeping the compartments' balances, and mai ...200818270728
conserved amphiphilic feature is essential for periplasmic chaperone hdea to support acid resistance in enteric bacteria.the extremely acidic environment of the mammalian stomach (ph 1-3) represents a stressful challenge for enteric pathogenic bacteria, including escherichia coli, shigella and brucella. the hdea (hns-dependent expression a) gene was found to be crucial for the survival of these enteric bacteria under extremely low ph conditions. we recently demonstrated that hdea is able to exhibit chaperone-like activity exclusively within the stomach ph range by transforming from a well-folded conformation at hi ...200818271752
reactive arthritis following culture-confirmed infections with bacterial enteric pathogens in minnesota and oregon: a population-based study.to describe the epidemiology and clinical spectrum of reactive arthritis (rea) following culture-confirmed infection with bacterial enteric pathogens in a population-based study in the usa.200818272671
immunogenicity and efficacy of highly purified invasin complex vaccine from shigella flexneri 2a.development of a subunit vaccine for shigellosis requires identification of protective antigens and delivering these antigens in a manner that stimulates immunity comparable to that induced by natural infection. the shigella invasin complex (invaplex) vaccine is an ion-exchange-purified extract from virulent shigella that consists of lps and several other proteins, including the invasins ipab and ipac. intranasal delivery of invaplex stimulates protective immunity in small animal models for shig ...200818276045
distribution and antibiotic susceptibility of shigella isolates in bangui, central african republic.we conducted a prospective study in four urban health care centres between january 2004 and november 2005 to determine the distribution and susceptibility patterns of shigella strains causing invasive diarrhoea in bangui, central african republic. of the 155 shigella isolated, shigella flexneri (51%) and shigella dysenteriae (30%) were the most common and the most resistant to usual antibiotics, including amoxicillin, sulphamethoxazole-trimethoprim and chloramphenicol. though multi-drug resistan ...200818282240
reaching a consensus on management practices and vaccine development targets for mitigation of infectious diarrhoea among deployed us military forces.this study is part of a research effort to identify and quantify factors related to the cost-effectiveness of a vaccine acquisition strategy to reduce the burden of infectious diarrhoea on us military personnel deployed overseas. where evidence is lacking in the scientific literature, or considerable uncertainty exists, it is often necessary to develop best estimates with ranges of certainty. to this end, a modified 'delphi' survey technique to obtain the best estimates for uncertain parameters ...200818284518
comparative analysis of intestinal microbial community diversity between healthy and orally infected ducklings with salmonella enteritidis by eric-pcr.to analyze the difference of intestinal microbial community diversity between healthy and (s. enteritidis) orally infected ducklings.200818286697
the shf gene of a shigella flexneri homologue on the virulent plasmid paa2 of enteroaggregative escherichia coli 042 is required for firm biofilm formation.enteroaggregative escherichia coli (eaec) is an increasingly important cause of diarrhea in both developing and industrialized countries, and is characterized by strong biofilm formation on the intestinal mucosa. sequencing of the virulent plasmid paa2 of the prototype eaec 042 revealed a cluster of three open reading frames (orfs; shf, capu, and virk) ca. 93% identical to a similar cluster located in shigella flexneri. the function of the first orf shf protein is not known, but the closest well ...200818293034
terpenoid compositions, and antioxidant and antimicrobial properties of the rhizome essential oils of different hedychium species.a phytochemical study of the rhizome essential oils of four different hedychium species was performed by means of gc and gc/ms analyses. h. ellipticum mainly contained 1,8-cineole, sabinene, and terpin-4-ol, while h. aurantiacum possessed terpin-4-ol, para-cymene, and bornyl acetate as the major entities. similarly, trans-meta-mentha-2,8-diene and linalool were noticed in h. coronarium. three different collections (i-iii) of h. spicatum showed amazing differences in the relative contents of thei ...200818293443
diverse antimicrobial killing by enterococcus faecium e 50-52 bacteriocin.an effective bacteriocin was identified and characterized. lactic acid bacteria were screened against campylobacter jejuni. one bacteriocin producer, enterococcus faecium (nrrl b-30746), was studied. the isolate was grown, and the bacteriocin was purified to single-band homogeneity. biochemical traits indicated that the peptide was a class iia bacteriocin, and it was named e 50-52. the bacteriocin had a molecular weight of 3339.7 and an isoelectric point of 8.0. the minimal inhibitory concentrat ...200818293921
association of a factor h mutation with hemolytic uremic syndrome following a diarrheal illness.hemolytic uremic syndrome (hus) takes 2 forms: diarrheal hus and nondiarrheal hus. as its name suggests, diarrheal hus classically follows an enteric infection. the classic infective organism is the escherichia coli o157 serotype, although other bacteria, including shigella species, can produce the verocytotoxin required to cause hus. the usual clinical course is an episode of bloody diarrhea followed by thrombotic microangiopathy and acute renal failure. supportive treatment sees recovery of re ...200818295065
single residue determines the specificity of neutrophil elastase for shigella virulence factors.human neutrophil elastase (ne) is a key host defense protease that cleaves virulence factors of gram-negative bacteria. ne and cathepsin g (cg) are chymotrypsin-like serine proteases with sequence and structural similarities, and both are abundant in neutrophil granules. unlike ne, cg does not cleave virulence factors of enteric bacteria. through structure-function analysis, we identified regions in ne that are essential for cleaving shigella virulence proteins. ne residues at eight different po ...200818295791
geographic analysis of shigellosis in vietnam.geographic and ecological analysis may provide investigators useful ecological information for the control of shigellosis. this paper provides distribution of individual shigella species in space, and ecological covariates for shigellosis in nha trang, vietnam. data on shigellosis in neighborhoods were used to identify ecological covariates. a bayesian hierarchical model was used to obtain joint posterior distribution of model parameters and to construct smoothed risk maps for shigellosis. neigh ...200818296100
socioeconomic risk factors for bacterial gastrointestinal infections.bacterial gastrointestinal infections cause considerable morbidity in industrialized countries, but little is known about socioeconomic factors affecting the risk of infection.200818300694
a five-year antimicrobial resistance pattern of shigella isolated from stools in the gondar university hospital, northwest ethiopia.shigellosis is a global health problem. however, developing countries, where there is poor hygiene and unsafe water supplies, are especially affected. in the last two decades shigella isolates have become increasingly resistant to many commonly used drugs. we investigated the antibiotic susceptibility pattern of shigella isolated from stool specimens processed over five years in the bacteriology laboratory of the university of gondar teaching hospital in northwest ethiopia. stool specimens were ...200818302868
structures of the shigella flexneri type 3 secretion system protein mxic reveal conformational variability amongst homologues.many gram-negative pathogenic bacteria use a complex macromolecular machine, known as the type 3 secretion system (t3ss), to transfer virulence proteins into host cells. the t3ss is composed of a cytoplasmic bulb, a basal body spanning the inner and outer bacterial membranes, and an extracellular needle. secretion is regulated by both cytoplasmic and inner membrane proteins that must respond to specific signals in order to ensure that virulence proteins are not secreted before contact with a euk ...200818304577
the o-polysaccharide of escherichia coli o112ac has the same structure as that of shigella dysenteriae type 2 but is devoid of o-acetylation: a revision of the s. dysenteriae type 2 o-polysaccharide structure.the o-antigen structure of shigella dysenteriae type 2 was reinvestigated using chemical modifications along with high-resolution 2d (1)h and (13)c nmr spectroscopy. the o-antigen was found to contain a pyruvic acid acetal, which was overlooked in an early study, and the following revised structure of the pentasaccharide repeating unit was established: where approximately 70% glcnac residues bear an o-acetyl group at position 3. the o-antigen of escherichia coli o112ac was found to have the same ...200818308298
nlrx1: friend or foe? 200818311173
ipgb1 and ipgb2, two homologous effectors secreted via the mxi-spa type iii secretion apparatus, cooperate to mediate polarized cell invasion and inflammatory potential of shigella flexenri.type iii secretion systems (t3ss) are present in many pathogenic gram-negative bacteria and mediate the translocation of bacterial effector proteins into host cells. here, we report the phenotypic characterization of s. flexneri ipgb1 and ipgb2 mutants, in which the genes encoding the ipgb1 and ipgb2 effectors have been inactivated, either independently or simultaneously. like ipgb1, we found that ipgb2 is secreted by the t3ss and its secretion requires the spa15 chaperone. upon infection of sem ...200818316224
a comparative synteny map of burkholderia species links large-scale genome rearrangements to fine-scale nucleotide variation in prokaryotes.genome rearrangement events, including inversions and translocations, are frequently observed across related microbial species, but the impact of such events on functional diversity is unclear. to clarify this relationship, we compared 4 members of the gram-negative burkholderia family (burkholderia pseudomallei, burkholderia mallei, burkholderia thailandensis, and burkholderia cenocepacia) and identified a core set of 2,590 orthologs present in all 4 species (metagenes). the metagenes were orga ...200818162473
role of escherichia coli in acute diarrhoea in tribal preschool children of central india.five hundred and eighty preschool children belonging to tribal areas of madhya pradesh were followed up daily for the presence of diarrhoea for a period of 1 year. in all, 1236 episodes of diarrhoea were recorded with an average of 2.13 episodes per child per year. stool samples were collected during 780 episodes. they were cultured to isolate escherichia coli as well as non-e. coli enteropathogens. ten different genes were detected to identify all diarrhoeagenic e. coli using multiplex polymera ...200818173783
diarrheagenic escherichia coli and shigella strains isolated from children in a hospital case-control study in hanoi, vietnam.this case-control study detected and characterized shigella and diarrheagenic escherichia coli (dec) types among vietnamese children less than 5 years old. in 249 children with diarrhea and 124 controls, shigella spp. was an important cause of diarrhea (p < 0.05). we used multiplex pcr and dna probes to detect enteroinvasive e. coli (eiec), enteroaggregative e. coli (eaggec), enteropathogenic e. coli (epec), attaching and effacing e. coli (a/eec), verocytotoxin-producing e. coli (vtec), and ente ...200818174300
full structural characterization of shigella flexneri m90t serotype 5 wild-type r-lps and its delta galu mutant: glycine residue location in the inner core of the lipopolysaccharide.shigella flexneri is a gram-negative bacterium responsible for serious enteric infections that occur mainly in the terminal ileum and colon. high interest in shigella, as a human pathogen, is driven by its antibiotic resistance and the necessity to develop a vaccine against its infections. vaccines of the last generation use carbohydrate moieties of the lipopolysaccharide as probable candidates. for this reason, the primary structure of the core oligosaccharide from the r-lps produced by s. flex ...200818174310
ph sensitivity of type iii secretion system tip proteins.many pathogenic gram-negative bacteria employ type iii secretion systems to transport proteins into the host cell membrane and cytoplasm to subvert normal cellular functions. the type iii secretion apparatus consists of a basal body spanning the inner and outer bacterial membranes and a needle which extends away from the bacterium. recent work has found that a special class of proteins localizes to the tip of the needle to control secretion of effector proteins. five of these tip proteins are ip ...200818175320
differential activation of human tlr4 by escherichia coli and shigella flexneri 2a lipopolysaccharide: combined effects of lipid a acylation state and tlr4 polymorphisms on signaling.the lipid a of lps activates tlr4 through an interaction with myeloid differentiation protein-2 (md-2) and the degree of lipid a acylation affects tlr4 responsiveness. two tlr4 single nucleotide polymorphisms (asp299gly and thr399ile) have been associated with lps hyporesponsiveness. we hypothesized that the combination of hypoacylation and these single nucleotide polymorphisms would exhibit a compounded effect on tlr4 signaling. hek293t transfectants expressing wild-type or polymorphic tlr4 wer ...200818178854
cmy-2-type plasmid-mediated ampc beta-lactamase finally emerging in argentina. 200818242960
on-line monitoring of microbial volatile metabolites by proton transfer reaction-mass spectrometry.a method for analysis of volatile organic compounds (vocs) from microbial cultures was established using proton transfer reaction-mass spectrometry (ptr-ms). a newly developed sampling system was coupled to a ptr-ms instrument to allow on-line monitoring of vocs in the dynamic headspaces of microbial cultures. the novel ptr-ms method was evaluated for four reference organisms: escherichia coli, shigella flexneri, salmonella enterica, and candida tropicalis. headspace vocs in sampling bottles con ...200818245241
eukaryotic expression and antimicrobial spectrum determination of the peptide tachyplesin ii.ta0-a, the gene encoding the mature antimicrobial peptide tachyplesin ii, was engineered to optimize the coding sequence according to codon usage bias in yeast. ta0-a was efficiently expressed in the methylotrophic yeast pichia pastoris strain smd1168. the recombinant peptide ta0 reached 150mg/l after methanol induction for 6 d. ta0 was rapidly purified to homogeneity by a single step of size-exclusion chromatography. the minimal lethal concentrations of ta0 to the escherichia coli strain k12 wa ...200818249136
traveler's myopericarditis.colitis caused by shigella is an uncommon etiology of infectious diarrhea in developed countries, usually presenting as traveler's diarrhea. aside from clinical intestinal manifestations, shigellosis can present with a wide variety of extra-intestinal symptoms. we present the case of a 38-year-old man with diarrhea, fever, and chest pain that started after a holiday in cape verde (africa). blood samples revealed an increase in cardiac enzymes. an electrocardiogram revealed a widespread elevation ...200818249314
regulation of expression and secretion of nleh, a new non-locus of enterocyte effacement-encoded effector in citrobacter rodentium.together with enterohemorrhagic escherichia coli and enteropathogenic escherichia coli, citrobacter rodentium is a member of the attaching-and-effacing (a/e) family of bacterial pathogens. a/e pathogens use a type iii secretion system (t3ss) to translocate an assortment of effector proteins, encoded both within and outside the locus of enterocyte effacement (lee), into the colonized host cell, leading to the formation of a/e lesions and disease. here we report the identification and characteriza ...200818223087
the origin of a novel gene through overprinting in escherichia coli.overlapped genes originate by a) loss of a stop codon among contiguous genes coded in different frames; b) shift to an upstream initiation codon of one of the contiguous genes; or c) by overprinting, whereby a novel open reading frame originates through point mutation inside an existing gene. although overlapped genes are common in viruses, it is not clear whether overprinting has led to new genes in prokaryotes.200818226237
nlrx1 is a mitochondrial nod-like receptor that amplifies nf-kappab and jnk pathways by inducing reactive oxygen species production.nod-like receptors (nlrs) are a family of intracellular sensors of microbial- or danger-associated molecular patterns. here, we report the identification of nlrx1, which is a new member of the nlr family that localizes to the mitochondria. nlrx1 alone failed to trigger most of the common signalling pathways, including nuclear factor-kappab (nf)-kappab- and type i interferon-dependent cascades, but could potently trigger the generation of reactive oxygen species (ros). importantly, nlrx1 synergis ...200818219313
cytoplasmic targeting of ipac to the bacterial pole directs polar type iii secretion in shigella.type iii secretion (t3s) systems are largely used by pathogenic gram-negative bacteria to inject multiple effectors into eukaryotic cells. upon cell contact, these bacterial microinjection devices insert two t3s substrates into host cell membranes, forming a so-called 'translocon' that is required for targeting of type iii effectors in the cell cytosol. here, we show that secretion of the translocon component ipac of invasive shigella occurs at the level of one bacterial pole during cell invasio ...200818188151
bacterial actin assembly requires toca-1 to relieve n-wasp autoinhibition.actin polymerization in the mammalian cytosol can be locally activated by mechanisms that relieve the autoinhibited state of n-wasp, an initiator of actin assembly, a process that also requires the protein toca-1. several pathogenic bacteria, including shigella, exploit this host feature to infect and disseminate efficiently. the shigella outer membrane protein icsa recruits n-wasp, which upon activation at the bacterial surface mediates localized actin polymerization. the molecular role of toca ...200818191793
antibacterial activities and cytotoxicity of terpenoids isolated from spirostachys africana.spirostachys africana sond. stem bark is used traditionally for the treatment of diarrhoea and dysentery in limpopo province of south africa. bioassay-guided fractionation of ethanolic extract from bark of spirostachys africana led to the isolation of four known compounds, two triterpenoids, compound 1 [d-friedoolean-14-en-oic acid (3-acetyl aleuritolic acid)] and compound 2 (lupeol), and two diterpenes, compound 3 [ent-2,6alpha-dihydroxy-norbeyer-1,4,15-trien-3-one (diosphenol 2)] and compound ...200818191928
the chaperone ipgc copurifies with the virulence regulator mxie.the expression of a subset of shigella flexneri virulence genes is dependent upon a cytoplasmic chaperone, ipgc, and an activator from the arac/xyls family, mxie. in this paper, we report that the chaperone forms a specific and stable heteromer with mxie.200818192384
role and regulation of iron-sulfur cluster biosynthesis genes in shigella flexneri virulence.shigella flexneri, a causative agent of bacterial dysentery, possesses two predicted iron-sulfur cluster biosynthesis systems called suf and isc. s. flexneri strains containing deletion mutations in the entire suf operon (ur011) or the iscsua genes (ur022) were constructed. both mutants were defective in surviving exposure to oxidative stress. the suf mutant showed growth that was comparable to that of the parental strain in both iron-replete and iron-limiting media; however, the isc mutant show ...200818195027
evaluation of faecal occult blood test and lactoferrin latex agglutination test in screening hospitalized patients for diagnosing inflammatory and non-inflammatory diarrhoea in dhaka, bangladesh.inflammatory diarrhoea (id) resulting from shigella, salmonella, campylobacter and entamoeba histolytica requires specific diagnosis for therapy. differentiation between id and non-inflammatory diarrhoea (nid) is often not clinically possible. a faecal occult blood test (fobt) correlates with faecal leucocytes. lactoferrin indicates an inflammatory process as a marker for faecal leucocytes. we evaluated diagnostic values of lactoferrin latex agglutination test (lt) either alone or in combination ...200818196900
new information about pediatric foodborne infections: the view from foodnet.diarrheal illness is a significant burden to children and their parents. recent studies describing the etiologic agents that cause diarrheal illness and examining the risk factors for the most common bacterial enteric pathogens are presented.200818197044
molecular pathogenesis of shigella spp.: controlling host cell signaling, invasion, and death by type iii secretion.shigella spp. are gram-negative pathogenic bacteria that evolved from harmless enterobacterial relatives and may cause devastating diarrhea upon ingestion. research performed over the last 25 years revealed that a type iii secretion system (t3ss) encoded on a large plasmid is a key virulence factor of shigella flexneri. the t3ss determines the interactions of s. flexneri with intestinal cells by consecutively translocating two sets of effector proteins into the target cells. thus, s. flexneri co ...200818202440
a comparison of self-reported joint symptoms following infection with different enteric pathogens: effect of hla-b27.we conducted a case-case comparison study to estimate the attack-rate of reactive joint pain (jprea) following intestinal infections, and evaluated whether the susceptibility and severity of joint symptoms was associated with the tissue-type hla-b27.200818203313
phase 1 clinical trial of live attenuated shigella dysenteriae type-1 deltaicsa deltaent deltafep deltastxa:hgr oral vaccine sc599 in healthy human adult volunteers.twenty-eight adults received between 10(2) and 10(8)colony forming units of live shigella dysenteriae type-1 vaccine sc599, attenuated by deletion of invasion (icsa), iron chelation (ent, fep) and shiga toxin a-subunit (stxa) genes, followed by ciprofloxacin on day 4. dose-independent diarrhea or change in bowel habit was seen in 3 subjects, without dysentery, vaccinaemia or serious adverse events. hematology and biochemical parameters were unchanged. doses of 10(5) or greater induced dose-indep ...200818207287
a functional genomic yeast screen to identify pathogenic bacterial proteins.many bacterial pathogens promote infection and cause disease by directly injecting into host cells proteins that manipulate eukaryotic cellular processes. identification of these translocated proteins is essential to understanding pathogenesis. yet, their identification remains limited. this, in part, is due to their general sequence uniqueness, which confounds homology-based identification by comparative genomic methods. in addition, their absence often does not result in phenotypes in virulenc ...200818208325
nitrate and bacterial contamination in well waters in vinh phuc province, vietnam.measurements were made of the nitrate concentration and bacterial contamination of groundwater samples taken from both dug wells and bores in the commune of hop thinh', in the administrative district of vinh phuc, vietnam. a significant number (18%) of samples had nitrate concentrations in excess of the who guideline value for drinking water of 50 mg l(-1), with a higher proportion in the dug wells (29%) than the bores (3.8%). high concentrations of thermotolerant coliforms were found in many of ...200818209289
selection and validation of a multilocus variable-number tandem-repeat analysis panel for typing shigella spp.the shigella genus has historically been separated into four species, based on biochemical assays. the classification within each species relies on serotyping. recently, genome sequencing and dna assays, in particular the multilocus sequence typing (mlst) approach, greatly improved the current knowledge of the origin and phylogenetic evolution of shigella spp. the shigella and escherichia genera are now considered to belong to a unique genomospecies. multilocus variable-number tandem-repeat (vnt ...200818216214
shigella from humans in thailand during 1993 to 2006: spatial-time trends in species and serotype distribution.in thailand during 1993-2006, a total of 9063 shigella isolates from different medical centers were serotyped and trends over time and spatial clustering analyzed. of 3583 cases with age information, 1315 (37%) cases were from children between 0 and 4 years and 684 (19%) from children between 5 and 8 years. most infections were recorded during 1993-1994 (> 1500 per year), decreasing to < 200 in 2006. the relative species distribution also changed. during 1993-1994, shigella flexneri accounted fo ...200819086804
[structures of o-polysaccharides from two shigella dysenteriae type 8 strains].the structure of the o-polysaccharide (o-antigen) from shigella dysenteriae type 8 bacteria (strain 599) was corrected using modern nmr techniques (structure 1). the revisions concerned the position of the glc residue (in the main, but not the side, chain), the site of its substitution, and the configuration of the o-glycoside linkage of the glcnac residue. the s. dysenteriae type 8 bacterium (strain g1221), the second investigated representative, was found to produce another structural variant ...200819088755
increased isolation and characterization of shigella sonnei obtained from hospitalized children in tehran, iran.shigella flexneri has been the most frequent cause of shigellosis in children in iran. to evaluate the changes in frequency of serogroups, 302 shigella species were isolated in 2003 from hospitalized children, aged less than 12 years, with acute diarrhoea in tehran, iran. the number of collected s. sonnei, s. flexneri, s. boydii, and s. dysenteriae isolates was 178 (58.9%), 110 (37.4%), 10 (3.3%), and 4 (1.3%) respectively. most (94%) s. sonnei isolates were resistant to co-trimoxazole. they wer ...200819069621
prevalence of bacteria and intestinal parasites among food-handlers in gondar town, northwest ethiopia.food-handlers with poor personal hygiene working in food-service establishments could be potential sources of infection due to pathogenic organisms. the study was undertaken to determine the prevalence of bacteria and intestinal parasites among 127 food-handlers working in the cafeterias of the university of gondar and the gondar teachers training college, gondar, ethiopia. fingernail contents of both the hands and stool specimens were collected from all the 127 food-handlers. the samples were e ...200819069624
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