Publications

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biosensors for efficient diagnosis of leishmaniasis: innovations in bioanalytics for a neglected disease.the need for reliable, fast diagnostics is closely linked to the need for safe, effective treatment of the so-called "neglected" diseases. the list of diseases with no field-adapted diagnostic tools includes leishmaniasis, shigella, typhoid, and bacterial meningitis. leishmaniasis, in particular, is a parasitic disease caused by leishmania spp. transmitted by infected phlebotomine sandfly, which remains a public health concern in developing countries with ca. 12 million people infected and 350 m ...201021043437
prevalence of shigellosis diarrhoea in a paediatrics population: hospital based survey in bangui, central african republic.shigellosis is still a major public health problem in sub-saharan countries, especially among children.201021045359
evaluation of bacterial multiplication in cleaning cloths containing different quantities of organic matter.to determine a proper length of time for cleaning cloth usage, the present work aimed to evaluate bacterial multiplication in artificially contaminated cleaning cloths containing different amounts of organic matter.201021045369
research progress in shigella in the postgenomic era.gram-negative, facultative intracellular anaerobes of the genus shigella, the principal etiologic agents of shigellosis, continue to pose a threat to public health. shigellosis causes 1.1 million deaths with over 164 million annual cases. the shigella spp. can be divided into four serogroups: shigella dysenteriae, shigella flexneri, shigella boydii and shigella sonnei. the completion of seven shigella genome sequences of representative strains from each of the shigella species has introduced an ...201021046319
detection of representative enteropathogenic bacteria, vibrio spp., pathogenic escherichia coli, salmonella spp., shigella spp., and yersinia enterocolitica, using a virulence factor gene-based oligonucleotide microarray.rapid identification of enteropathogenic bacteria in stool samples is critical for clinical diagnosis and antimicrobial therapy. in this study, we describe the development of an approach that couples multiplex pcr with hybridization to a dna microarray, to allow the simultaneous detection of the 10 pathogens. the microarray was synthesized with 20-mer oligonucleotide probes that were designed to be specific for virulence-factor genes of each strain. the detection limit for genomic dna from a sin ...201021046348
controlled study on enteropathogens in travellers returning from the tropics with and without diarrhoea.clin microbiol infect abstract: diarrhoea is the most frequent health problem among travellers in the tropics. however, data on the spectrum and relevance of enteropathogens in international travellers with and without diarrhoea are limited. stool samples from 114 cases of diarrhoea in travellers returning from the tropics were collected for microbiological examination and pcr for norovirus genogroups i and ii, enteroaggregative escherichia coli (eaec), and enterotoxigenic e. coli (etec) produci ...201021054662
[detection and drug resistance analysis of extended-spectrum beta-lactamases-producing shigella in pediatric patients].to investigate the occurrence and drug resistance of extended-spectrum beta-lactamases (esbls)-producing strains of shigella in pediatric patients, so as to provide information for clinical treatment.201021055309
biochemical characterization of udp-gal:glcnac-pyrophosphate-lipid β-1,4-galactosyltransferase wfed, a new enzyme from shigella boydii type 14 that catalyzes the second step in o-antigen repeating-unit synthesis.the o antigen is the outer part of the lipopolysaccharide (lps) in the outer membrane of gram-negative bacteria and contains many repeats of an oligosaccharide unit. it contributes to antigenic variability and is essential to the full function and virulence of bacteria. shigella is a gram-negative human pathogen that causes diarrhea in humans. the o antigen of shigella boydii type 14 consists of repeating oligosaccharide units with the structure [→6-d-galpα1→4-d-glcpaβ1→6-d-galpβ1→4-d-galpβ1→4-d ...201021057010
comparison of chromogenic biolog rainbow agar shigella/aeromonas with xylose lysine desoxycholate agar for isolation and detection of shigella spp. from foods.shigella outbreaks are widely reported throughout the world. however, it remains a challenge to isolate shigella spp. from foods by using conventional microbiological media. the main objective of this study was to determine the effectiveness of a novel chromogenic medium, rainbow agar shigella/aeromonas (rainbow agar), for the isolation and detection of shigella spp. in foods. all four shigella species, s. sonnei, s. flexneri, s. dysenteriae, and s. boydii, were studied. rainbow agar was compare ...201020819355
[the evolution of the etiological structure of shigellosis]. 201020734730
plasmon-induced inactivation of enteric pathogenic microorganisms with ag-agi/al2o3 under visible-light irradiation.the plasmon-induced photocatalytic inactivation of enteric pathogenic microorganisms in water using ag-agi/al(2)o(3) under visible-light irradiation was investigated. the catalyst was found to be highly effective at killing shigella dysenteriae (s. dysenteriae), escherichia coli (e. coli), and human rotavirus type 2 wa (hrv-wa). its bactericidal efficiency was significantly enhanced by hco(3)(-) and so(4)(2-) ions, which are common in water, while phosphate had a slightly positive effect on the ...201020734989
enhancement of reactive oxygen species production and chlamydial infection by the mitochondrial nod-like family member nlrx1.chlamydia trachomatis infections cause severe and irreversible damage that can lead to infertility and blindness in both males and females. following infection of epithelial cells, chlamydia induces production of reactive oxygen species (ros). unconventionally, chlamydiae use ros to their advantage by activating caspase-1, which contributes to chlamydial growth. nlrx1, a member of the nod-like receptor family that translocates to the mitochondria, can augment ros production from the mitochondria ...201020959452
prominent human health impacts from several marine microbes: history, ecology, and public health implications.this paper overviews several examples of important public health impacts by marine microbes and directs readers to the extensive literature germane to these maladies. these examples include three types of dinoflagellates (gambierdiscus spp., karenia brevis, and alexandrium fundyense), bmaa-producing cyanobacteria, and infectious microbes. the dinoflagellates are responsible for ciguatera fish poisoning, neurotoxic shellfish poisoning, and paralytic shellfish poisoning, respectively, that have pl ...201020976073
ikkα contributes to canonical nf-κb activation downstream of nod1-mediated peptidoglycan recognition.during pathogen infection, innate immunity is initiated via the recognition of microbial products by pattern recognition receptors and the subsequent activation of transcription factors that upregulate proinflammatory genes. by controlling the expression of cytokines, chemokines, anti-bacterial peptides and adhesion molecules, the transcription factor nuclear factor-kappa b (nf-κb) has a central function in this process. in a typical model of nf-κb activation, the recognition of pathogen associa ...201020976174
atypical class 1 integron coexists with class 1 and class 2 integrons in multi-drug resistant shigella flexneri isolates from china.the antimicrobial resistance and the character of integrons were determined in 58 shigella flexneri strains isolated from china. all isolates were multi-drug resistant and found to carry integrons of class 1 (94.8%), class 2 (100%), or both (94.8%). no inti3 was detected. the typical class 1 integrons were found in conjugative plasmids and could be transferred to the recipient e. coli dh5α. the gene cassettes of typical class 1 integrons dfra17-aada5 and dfra12-orff-aada2 were detected in 54 str ...201020976456
[susceptibility surveillance of clinical isolates to fluoroquinolone antimicrobial agents from 2003 to 2008: post-marketing study of prulifloxacin].yearly changes in the susceptibility of clinical isolates to ulifloxacin (ufx) and other fluoroquinolones were examined through surveys over 3 periods. in the first survey, 534 strains derived from 19 species were collected from clinical specimens during 6 months from december 2003 to may 2004. in the same way, 805 strains were collected from december 2005 to may 2006 in the second survey, and 863 strains were from december 2007 to may 2008 in the third survey. over these 3 study periods, the su ...201020976880
near-atomic resolution analysis of bipd, a component of the type iii secretion system of burkholderia pseudomallei.burkholderia pseudomallei, the causative agent of melioidosis, possesses a type iii protein secretion apparatus that is similar to those found in salmonella and shigella. a major function of these secretion systems is to inject virulence-associated proteins into target cells of the host organism. the bipd gene of b. pseudomallei encodes a secreted virulence factor that is similar in sequence and is most likely to be functionally analogous to ipad from shigella and sipd from salmonella. proteins ...201020823511
molecular mechanisms of necroptosis: an ordered cellular explosion.for a long time, apoptosis was considered the sole form of programmed cell death during development, homeostasis and disease, whereas necrosis was regarded as an unregulated and uncontrollable process. evidence now reveals that necrosis can also occur in a regulated manner. the initiation of programmed necrosis, 'necroptosis', by death receptors (such as tumour necrosis factor receptor 1) requires the kinase activity of receptor-interacting protein 1 (rip1; also known as ripk1) and rip3 (also kn ...201020823910
development of a multiplex real-time pcr assay with internal amplification control for the detection of shigella species and enteroinvasive escherichia coli.shigella species, particularly s. sonnei and s. flexneri, remain some of the leading bacterial etiological agents of gastrointestinal diseases in the united states and globally. the isolation and detection of these foodborne pathogens are critical for preventing the spread of disease and facilitating epidemiological investigations aimed at determining the source of a shigella infection outbreak. a multiplex real-time pcr-based assay was developed that targets all four species of shigella plus en ...201020828467
a disulfide driven domain swap switches off the activity of shigella ipah9.8 e3 ligase.we show that the monomeric form of shigella ipah9.8 e3 ligase catalyses the ubiquitination of human u2af35 in vitro, providing a molecular mechanism for the observed in vivo effect. we further discover that under non-reducing conditions ipah9.8 undergoes a domain swap driven by the formation of a disulfide bridge involving the catalytic cysteine and that this dimer is unable to catalyse the ubiquitination of u2af35. the crystal structure of the domain-swapped dimer is presented. the redox inacti ...201020831869
the effects of x-ray radiation on escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri inoculated on whole roma tomatoes.in the last two decades several foodborne disease outbreaks associated with produce were reported. tomatoes, in particular, have been associated with several multi-state salmonella outbreaks. inactivation of inoculated escherichia coli o157:h7, listeria monocytogenes, salmonella enterica and shigella flexneri on whole roma tomato surfaces by x-ray at 0.1, 0.5, 0.75, 1.0, and 1.5 kgy was studied. the main purpose of this study was to achieve a 5 log reduction in consistent with the recommendation ...201020832685
transmembrane bax inhibitor motif containing (tmbim) family proteins perturbs a trans-golgi network enzyme, gb3 synthase, and reduces gb3 biosynthesis.globotriaosylceramide (gb3) is a well known receptor for shiga toxin (stx), produced by enterohemorrhagic escherichia coli and shigella dysenteriae. the expression of gb3 also affects several diseases, including cancer metastasis and fabry disease, which prompted us to look for factors involved in its metabolism. in the present study, we isolated two cdnas that conferred resistance to stx-induced cell death in hela cells by expression cloning: ganglioside gm3 synthase and the cooh terminus regio ...201020837469
normal aerobic bacterial conjunctival flora in the crab-eating raccoon (procyon cancrivorus) and coati (nasua nasua) housed in captivity in pernambuco and paraiba (northeast, brazil).to determine the normal aerobic bacterial conjunctival population of the coatis and the crab-eating raccoons housed in captivity in the pernambuco and paraiba states of brazil.201020840103
mass spectrometry biotyper system identifies enteric bacterial pathogens directly from colonies grown on selective stool culture media.we evaluated the performance and cost-effectiveness of a matrix-assisted laser desorption ionization time-of-flight mass spectrometry-based biotyper system for the routine identification of common enteric bacterial pathogens seen in middle tennessee from suspicious colonies grown on selective stool culture media. a total of 304 suspicious colonies were selected and further identified from 605 stool specimens. the suspicious colonies were analyzed by the biotyper system, and the results were comp ...201020844226
formulation and immunogenicity studies of type iii secretion system needle antigens as vaccine candidates.bacterial infections caused by shigella flexneri, salmonella typhimurium, and burkholderia pseudomallei are currently difficult to prevent due to the lack of a licensed vaccine. here we present formulation and immunogenicity studies for the three type iii secretion system (ttss) needle proteins mxih(δ5), prgi(δ5), and bsal(δ5) (each truncated by five residues at its c terminus) as potential candidates for vaccine development. these antigens are found to be thermally stabilized by the presence of ...201020845448
formulation and immunogenicity of a potential multivalent type iii secretion system-based protein vaccine.the virulence of many pathogenic gram-negative bacteria is dependent upon their type iii secretion (tts) systems. here, we discuss initial formulation studies of five tts needle tip proteins ipad (shigella flexneri), bipd (burkholderia pseudomallei), sipd (salmonella spp.), lcrv (yersinia spp.), and pcrv (pseudomonas aeruginosa) as targets for subunit vaccines. excipient screening and subsequent assays lead to the selection of 10% sucrose and 5% dextrose as an optimal stabilizer combination for ...201020845449
assessment of the microbiological safety of dried spices and herbs commercialized in spain.spices and herbs are natural products or their blends that must be free of extraneous matter content. conventional production of these products implicates a number of hygienic problems so spices and herbs may be exposed to a wide range of microbial contamination during pre- and post-harvest and they can present high microbial counts. in this study, we have analyzed the microbial quality of 53 samples of spices and dry herbs collected from spanish markets detecting a contamination of samples of s ...201020848208
dysbiosis of fecal microbiota in crohn's disease patients as revealed by a custom phylogenetic microarray.a custom phylogenetic microarray composed of small subunit ribosomal rna probes, representing ≈500 bacterial species from the human and animal gut, was developed and evaluated for analysis of gut microbial diversity using fecal samples from healthy subjects and crohn's disease (cd) patients.201020848492
predacious bacteria, bdellovibrio with potential for biocontrol.bacteria of the genus of bdellovibrio are highly motile gram-negative predators of other gram-negative bacteria causing lysis of their prey. here we report results of studies on the interactions of bdellovibrio with species of alcaligenes, campylobacter, erwinia, escherichia, helicobacter, pseudomonas, legionella, and shigella in agar lower, liquid media and cells attached to a surface. helicobacter pylori was studied employing both actively growing and viable but nonculturable (vbnc) cells. the ...201020850380
infectious colitis.purpose of review: the incidence of gastrointestinal infections continues to increase and infectious colitis contributes to significant morbidity and mortality worldwide. the purpose of this review is to highlight the recent advances in knowledge of pathogens causing infectious colitis. we describe the various pathogens and specifically focus on enterohemorrhagic escherichia coli (ehec) o157:h7, salmonella, shigella, campylobacter, and entamoeba histolytica infections, and their impact on long-t ...201020856114
prevalence of bacteria and parasites in white ibis in egypt.a field survey was conducted to evaluate the prevalence of bacterial infections among free-living white ibis (nipponia nippon) in which 92 bacterial isolates were recovered from 193 different internal organs of 55 apparently healthy ibis. escherichia coli and salmonella spp. were isolated at rates of 43.6% and 14.5%, respectively. the other bacterial pathogens isolated were shigella spp. (34.5%), enterobacter spp. (21.8%) citrobacter spp. (18.1%), klebsiella pneumonia (16.3), staphylococcus aure ...201020857378
improved detection of five major gastrointestinal pathogens by use of a molecular screening approach.the detection of bacterial and parasitic gastrointestinal pathogens through culture and microscopy is laborious and time-consuming. we evaluated a molecular screening approach (msa) for the detection of five major enteric pathogens: salmonella enterica, campylobacter jejuni, giardia lamblia, shiga toxin-producing escherichia coli (stec), and shigella spp./enteroinvasive e. coli (eiec), for use in the daily practice of a clinical microbiology laboratory. the msa consists of prescreening of stool ...201020861334
antidiarrheal activity of extracts and compound from trilepisium madagascariense stem bark.the present study was performed to evaluate the preventive and curative antidiarrheal effects of the methanol extract, fractions and compound from the stem bark of trilepisium madagascariense in rats.201020871767
defensins play a crucial role in protecting mice against oral shigella flexneri infection.an earlier study revealed that 4-day-old mice, but not older mice, were infected with invasive shigella strains. here we attempted to determine the underlying mechanism that induces inflammation in the intestines of neonate mice after oral shigella infection. wild-type balb/c mice of different ages (7, 14, and 35 days old) were orally administered gfp-expressing shigella flexneri 5a m90t strain (5 x 10⁹ cfu) and analyzed for colonization 6h following infection. we found that shigella localized i ...201020888321
improved fructosylated chondroitin production by kfoc overexpression in e. coli k4.escherichia coli k4 is one of the bacteria expressing a surface polysaccharide, indicated as capsular polysaccharide (k-antigen), showing a chemical structure that resembles that of metabolites commonly used in pharmaceutical applications. in this study we provide evidence that homologous overexpression of the chondroitin polymerase, encoded by the kfoc gene, acts on a potential bottleneck for production of capsular polysaccharide, and increases productivity by 100%. however, we also demonstrate ...201020888875
pediatric diarrhea in southern ghana: etiology and association with intestinal inflammation and malnutrition.diarrhea is a major public health problem that affects the development of children. anthropometric data were collected from 274 children with (n = 170) and without (n = 104) diarrhea. stool specimens were analyzed by conventional culture, polymerase chain reaction for enteroaggregative escherichia coli (eaec), shigella, cryptosporidium, entamoeba, and giardia species, and by enzyme-linked immunosorbent assay for fecal lactoferrin levels. about 50% of the study population was mildly to severely m ...201020889896
selective testing of ß-galactosidase activity in the laboratory identification of salmonella and shigella species.salmonella and shigella species are pathogens of great medical and public health importance. however, laboratory identification of these organisms is time consuming. using current standard laboratory algorithms, the vast majority of organisms submitted for serological typing with salmonella-specific and shigella-specific antisera are not clinically significant.201020924038
bacterial enteropathogens and risk factors associated with childhood diarrhea.to investigate the etiology of bacterial enteropathogens causing diarrhea among children; to elucidate the risk factors, sign and symptoms involved in developing of infection; and to identify the antimicrobial susceptibility pattern.201020924718
[screening of harmine tolerance/degrading bacteria from camel rumen].peganum harmala, a famous traditional chinese drug, contains a variety of alkaloids and toxic for many animals. camels mainly live in desert or semi-desert areas, with the robust gastrointestine system in digesting various feed including toxic plants without disease symptoms.201020931866
viable but nonculturable state of foodborne pathogens in grapefruit juice: a study of laboratory.several foodborne human pathogens, when exposed to harsh conditions, enter viable but nonculturable (vbnc) state; however, still open is the question whether vbnc pathogens could be a risk for public health, because, potentially, they can resuscitate. moreover, cultural methods for food safety control were not able to detect vbnc forms of foodborne bacteria. particularly, it has not been established whether food chemophysical characteristics can induce vbnc state in contaminating pathogen bacter ...201020932087
shigella deploy multiple countermeasures against host innate immune responses.although the intestinal epithelium is equipped with multiple defense systems that sense bacterial components, transmit alarms to the immune system, clear the bacteria, and renew the injured epithelial lining, mucosal bacterial pathogens are capable of efficiently colonizing the intestinal epithelium, because they have evolved systems that modulate the inflammatory and immune responses of the host and exploit the harmful environments as replicative niches. in this review we highlight current topi ...201020934372
domains of the shigella flexneri type iii secretion system ipab protein involved in secretion regulation.type iii secretion systems (t3sss) are key determinants of virulence in many gram-negative bacterial pathogens. upon cell contact, they inject effector proteins directly into eukaryotic cells through a needle protruding from the bacterial surface. host cell sensing occurs through a distal needle "tip complex," but how this occurs is not understood. the tip complex of quiescent needles is composed of ipad, which is topped by ipab. physical contact with host cells initiates secretion and leads to ...201020937761
combination of two separate binding domains defines stoichiometry between type iii secretion system chaperone ipgc and translocator protein ipab.type iii secretion systems (ttsss) utilized by enteropathogenic bacteria require the presence of small, acidic virulence-associated chaperones for effective host cell infection. we adopted a combination of biochemical and cellular techniques to define the chaperone binding domains (cbds) in the translocators ipab and ipac associated with the chaperone ipgc from shigella flexneri. we identified a novel cbd in ipab and furthermore precisely mapped the boundaries of the cbds in both translocator pr ...201020937829
characterization and antimicrobial activity of 4-(β-d-glucopyranosyl-1→4-α-l-rhamnopyranosyloxy)-benzyl thiocarboxamide; a novel bioactive compound from moringa oleifera seed extract.antimicrobial activity of crude seed extract of moringa oleifera was investigated by thin layer chromatography bioassay against escherichia coli, pseudomonas aeruginosa, staphylococcus aureus, cladosporium cladosporioides, and penicillium sclerotigenum; most of them were prominently inhibited by an isolate with r(f) 0.92-0.96. characterization and identification of the extract revealed the occurrence of three bioactive compounds: 4-(α-l-rhamnopyranosyloxy)benzyl isothiocyanate, methyl n-4-(α-l-r ...201020941575
expression of bacterial virulence factors and cytokines during in vitro macrophage infection by enteroinvasive escherichia coli and shigella flexneri: a comparative study.enteroinvasive escherichia coli (eiec) and shigella spp cause bacillary dysentery in humans by invading and multiplying within epithelial cells of the colonic mucosa. although eiec and shigella share many genetic and biochemical similarities, the illness caused by shigella is more severe. thus, genomic and structure-function molecular studies on the biological interactions of these invasive enterobacteria with eukaryotic cells have focused on shigella rather than eiec. here we comparatively stud ...201020944993
an fda bioinformatics tool for microbial genomics research on molecular characterization of bacterial foodborne pathogens using microarrays.advances in microbial genomics and bioinformatics are offering greater insights into the emergence and spread of foodborne pathogens in outbreak scenarios. the food and drug administration (fda) has developed a genomics tool, arraytrack™, which provides extensive functionalities to manage, analyze, and interpret genomic data for mammalian species. arraytrack™ has been widely adopted by the research community and used for pharmacogenomics data review in the fda's voluntary genomics data submissio ...201020946615
integron types, gene cassettes, antimicrobial resistance genes and plasmids of shigella sonnei isolates from outbreaks and sporadic cases in taiwan.this study analysed the presence, location and transferability of integrons and antibiotic resistance genes in 103 shigella sonnei outbreak isolates and in 32 sporadic isolates from taiwan. multiple antimicrobial resistance was common in both outbreak (95 %) and sporadic (97 %) isolates. class 1 integrons were present in 34 outbreak isolates (33 %) and in six sporadic isolates (19 %). this study is the first, to our knowledge, to identify an atypical sul3-associated class 1 integron carrying the ...201020947666
rapid multiple-locus variable-number tandem-repeats analysis of shigella spp. using multicolour capillary electrophoresis.the multiple-locus variable-number tandem-repeats analysis (mlva) method for genotyping has proven to be a fast and reliable typing tool in several bacterial species. mlva is in our laboratory the routine typing method for salmonella enterica subsp. enterica serovar typhimurium, escherichia coli (two assays), listeria monocytogenes and yersinia enterocolitica. the gram-negative invasive enteropathogenic bacterium shigella is the most common cause of bacillary dysentery (shigellosis) worldwide, a ...201020951171
surveillance of shigellosis by real-time pcr suggests underestimation of shigellosis prevalence by culture-based methods in a population of rural china.shigellosis is a leading public health issue in china, especially in children under 5 years of age. the disease burden of shigellosis is usually underestimated by conventional culture. in this study, real-time pcr was applied to detect shigella infection in parallel with routine culture, to investigate the true burden of disease caused by shigella spp.201020951728
subtype prevalence, plasmid profiles and growing fluoroquinolone resistance in shigella from kolkata, india (2001-2007): a hospital-based study.shigellosis is a major public health problem, and increasing antimicrobial resistance has complicated its treatment. we report isolation frequency, plasmid profiles and antimicrobial resistance of shigella subtypes in kolkata, india, from a prospective hospital-based study.201020955371
enterobacteriaceae associated with eggs of podocnemis expansa and podocnemis unifilis (testudines:chelonia) in nonpolluted sites of national park of araguaia plains, brazil.fertile eggs of podocnemis expansa and podocnemis unifilis were investigated for the presence of enterobacteria, as these two endangered species have the potential for conservation measures that include egg transfer. knowledge of normal microflora associated with turtles and turtle eggs would help effectively manage the transfer of these eggs among institutions. thirty eggs of each species were collected, aseptically transferred, cracked inside plastic bags containing tetrathionate broth, and sp ...201021370647
ribonucleases and bacterial virulence.bacterial stress responses provide them the opportunity to survive hostile environments, proliferate and potentially cause diseases in humans and animals. the way in which pathogenic bacteria interact with host immune cells triggers a complicated series of events that include rapid genetic re-programming in response to the various host conditions encountered. viewed in this light, the bacterial host-cell induced stress response (hcisr) is similar to any other well-characterized environmental str ...201021375713
shiga toxin is transported into the nucleoli of intestinal epithelial cells via a carrier-dependent process.shiga toxin (stx) produced by the invasive shigella dysenteriae serotype 1 (s. dysenteriae1) causes gastrointestinal and kidney complications. it has been assumed that stx is released intracellularly after enterocyte invasion by s. dysenteriae1. however, there is little information about stx distribution inside s. dysenteriae1-infected enterocytes. here, we use intestinal epithelial t84 cells to characterize the trafficking of stx delivered into the cytosol, in ways that mimic aspects of s. dyse ...201022069640
shiga toxins: intracellular trafficking to the er leading to activation of host cell stress responses.despite efforts to improve hygenic conditions and regulate food and drinking water safety, the enteric pathogens, shiga toxin-producing escherichia coli (stec) and shigella dysenteriae serotype 1 remain major public health concerns due to widespread outbreaks and the severity of extra-intestinal diseases they cause, including acute renal failure and central nervous system complications. shiga toxins are the key virulence factors expressed by these pathogens mediating extra-intestinal disease. de ...201022069648
serine protease autotransporters of enterobacteriaceae (spates): biogenesis and function.serine protease autotransporters of enterobacteriaceae (spates) constitute a large family of proteases secreted by escherichia coli and shigella. spates exhibit two distinct proteolytic activities. first, a c-terminal catalytic site triggers an intra-molecular cleavage that releases the n-terminal portion of these proteins in the extracellular medium. second, the secreted n-terminal domains of spates are themselves proteases; each contains a canonical serine-protease catalytic site. some of thes ...201022069633
cytoskeleton-modulating effectors of enteropathogenic and enterohemorrhagic escherichia coli: a case for espb as an intrinsically less-ordered effector.enterohemorrhagic and enteropathogenic escherichia coli produce various effector proteins that are directly injected into the host-cell cytosol through the type iii secretion system. e. coli secreted protein (esp)b is one such effector protein, and affects host-cell morphology by reorganizing actin networks. unlike most globular proteins that have well-ordered, rigid structures, the structures of type iii secretion system effectors from pathogenic gram-negative bacteria, including espb, are ofte ...201020477867
etiology of childhood diarrhea in the northeast of brazil: significant emergent diarrheal pathogens.in a study conducted in joão pessoa, northeast of brazil, 2344 escherichia coli isolated from 290 infants with diarrhea and 290 healthy matched controls were analyzed for virulence traits. enteroaggregative e. coli (eaec) was the most prevalent pathogen associated to acute diarrhea. based on the results of colony blot hybridization, serotyping, and hep-2 cell adherence assays, strains were separated in categories as typical enteropathogenic e. coli (epec) (1.7%), atypical epec (a-epec) (9.3%), e ...201018508227
mitracarpus frigidus aerial parts exhibited potent antimicrobial, antileishmanial, and antioxidant effects.the crude extract and the hexane, ch(2)cl(2), etoac, n-buoh, and hydromethanolic fractions of the aerial parts of mitracarpus frigidus were evaluated against promastigote forms of two species of leishmania (l. chagasi and l. amazonensis), 11 strains of bacteria (staphylococcus aureus, pseudomonas aeruginosa, salmonella enterica sorovar tythimurium, shigella sonnei, klebsiella pneumoniae, escherichia coli, micrococcus luteus, enterococcus faecalis, enterobacter cloacae, streptococcus pyogenes and ...200918644325
antimicrobial activity of broth fermented with kefir grains.kefir grains originate from the caucasus region and are used for preparing beverages using sugar solution, milk, and fruit juice. as long as they are formed by a microbial consortium useful in the intestine, the produced drinks can be called probiotics. the aim of this study was to determine the antimicrobial activity during kefir fermentation in sugar broth. fermentations with three kinds of carbohydrates (molasses, demerara sugar, and brown sugar) as carbon source were carried out. brown sugar ...200918663417
acanthamoeba castellanii an environmental host for shigella dysenteriae and shigella sonnei.the interaction between shigella dysenteriae or shigella sonnei and acanthamoeba castellanii was studied by viable counts, gentamicin assay and electron microscopy. the result showed that shigella dysenteriae or shigella sonnei grew and survived in the presence of amoebae for more than 3 weeks. gentamicin assay showed that the shigella were viable inside the acanthamoeba castellanii which was confirmed by electron microscopy that showed the shigella localized in the cytoplasm of the acanthamoeba ...200918712360
effect of lactoferrin on enteric pathogens.much has been learned in recent years about the mechanisms by which breastfeeding improves child health and survival. however, there has been little progress in using these insights to improve pediatric care. factors that are important for protecting the breast fed infant might be expected to decrease the adverse effects of weaning on diarrhea, growth, and development. lactoferrin, an iron-binding protein with multiple physiological functions (anti-microbial, anti-inflammatory, and immunomodulat ...200918472012
international foodborne outbreak of shigella sonnei infection in airline passengers.during 22-24 august 2004, an outbreak of shigella sonnei infection affected air travellers who departed from hawaii. forty-seven passengers with culture-confirmed shigellosis and 116 probable cases who travelled on 12 flights dispersed to japan, australia, 22 us states, and american samoa. all flights were served by one caterer. pulsed-field gel electrophoresis of all 29 s. sonnei isolates yielded patterns that matched within one band. food histories and menu reviews identified raw carrot served ...200918177516
[shigella strategy for host defense and mucosal infection]. 200921089529
shigella species and serotypes among clinical isolates in thailand from 2001 to 2005.to study the species and the serotypes of the clinical isolates of shigella obtained from patients in thailand.200921298848
magnitude of drug resistant shigellosis: a report from bangalore.shigella is an important cause of acute invasive diarrhea in children and others. antimicrobial susceptibility of shigella spp. isolated from diarrhoeal/ dysenteric patients in bangalore was studied in our hospital from january 2002 to december 2007. one hundred and thirty-four isolates were identified as shigella species. s. flexneri, s. sonnei , s. boydii and s. dysenteriae were accounted respectively for 64.9%, 21.6%, 8.2% and 3.7% of the total number of shigella isolated. of these 56 (41.8%) ...200919736408
transmission risk factors and treatment of pediatric shigellosis during a large daycare center-associated outbreak of multidrug resistant shigella sonnei: implications for the management of shigellosis outbreaks among children.shigellosis outbreaks in daycare centers result in substantial disease and economic burdens in the united states. the emergence of multidrug resistant shigella strains raises questions regarding control of transmission within daycare centers and treatment for children. from may to october 2005, 639 shigella sonnei cases were reported in northwest missouri, mostly among persons exposed to daycare centers.200919738503
high-affinity inhibitors of trna-guanine transglycosylase replacing the function of a structural water cluster.the trna-modifying enzyme trna-guanine transglycosylase (tgt) is essential for the pathogenic mechanism of shigella flexneri, the causing agent of the bacterial diarrheal disease shigellosis. herein, the synthesis of a new class of rationally designed 6-amino-imidazo[4,5-g]quinazolin-8(7h)-one- (lin-benzoguanine) based inhibitors of tgt are reported. in order to accommodate a small hydrophobic crevice opening near the binding site of ribose-34, 2-aminoethyl substituents were introduced in positi ...200919746363
analysis of a temporal cluster of shigella boydii isolates in mpumalanga, south africa, november to december 2007.shigellosis is a global human health problem. the disease is most prevalent in developing countries with poor access to safe potable water and sanitation. shigella boydii is of particular epidemiological importance in developing nations such as african and asian countries. in the present study, we report on the analysis of a temporal cluster of 29 s. boydii serotype 2 strains, isolated in the mpumalanga province of south africa (sa) over the period of november to december 2007.200919749451
bcl-2 regulates the onset of shiga toxin 1-induced apoptosis in thp-1 cells.shiga toxins (stxs), which are proteins expressed by the enteric pathogens shigella dysenteriae serotype 1 and some serotypes of escherichia coli, are potent protein synthesis inhibitors. stx-producing organisms cause bloody diarrhea with the potential to progress to acute renal failure and central nervous system complications. studies using animal models of these diseases have shown that stxs are major virulence factors, and purified toxins have been shown to be capable of killing many types of ...200919752028
isolation of salmonella and shigella from fish harvested from the winam gulf of lake victoria, kenya.human infections caused by pathogens transmitted from fish are quite common. the aim of this study was to isolate enteric pathogenic bacteria from fish that might be transmitted to humans after the handling or consumption of such fish.200919755738
molecular characterization of esbl-producing shigella sonnei isolates from patients with bacilliary dysentery in lebanon.emergence of extended-spectrum beta-lactamases (esbls) in shigella species imparting resistance to third-generation cephalosporins is a growing concern worldwide. the aim of this study is to molecularly characterize the newly emerging beta-lactam resistant shigella sonnei, specifically esbls in lebanon, and compare them to beta-lactam sensitive isolates.200919759494
effect of iron on cytolysin a expression in salmonella enterica serovar typhi.previously, a novel protein clya (cytolysin a) has been identified in escherichia coli k-12, salmonella enterica serovars typhi and paratyphi a and shigella. salmonella spp. synthesize substantial amounts of clya upon infection of the human host, although the mechanism by which clya is induced in vivo is unclear. since environmental signals could control the expression of virulence determinants, clya expression in s. typhi ty2 was tested by western blotting in the presence of normal pooled human ...200919763423
study on induction of apoptosis on hela and vero cells by recombinant shiga toxin and its subunits.verotoxin (vt) or shiga toxin (stx) produced by enterohemorrhagic escherichia coli (ehec) and shigella dysenteriae is ab5 holotoxin with potent protein synthesis inhibitor. vt can induce both apoptosis and necrosis depending on the cell type, it has been shown that vt-induced apoptosis and cytotoxicity are distinct processes, and the a subunit can be necessary for apoptosis. in other words, the precise role of each subunit in apoptosis signaling has yet to be established. in this study, inductio ...200919669659
bacterial jailbreak sounds cellular alarm: phagosome membrane remnants trigger signaling.shigella flexneri and other invasive bacteria rupture the phagosome membrane and escape to the host cytoplasm. now, dupont et al. address the fate and signaling functions of pathogen vacuole remnants and show that these membrane fragments trigger host-cell-signaling responses, including polyubiquitination, autophagy, and pyroptosis.200919683675
shigella phagocytic vacuolar membrane remnants participate in the cellular response to pathogen invasion and are regulated by autophagy.intracellular pathogens like shigella flexneri enter host cells by phagocytosis. once inside, the pathogen breaks the vacuolar membrane for cytosolic access. the fate and function of the vacuolar membrane remnants are not clear. examining shigella-infected nonmyeloid cells, we observed that proteins associated with vacuolar membrane remnants are polyubiquinated, recruit the autophagy marker lc3 and adaptor p62, and are targeted to autophagic degradation. further, inflammasome components and casp ...200919683680
a genome-scale proteomic screen identifies a role for dnak in chaperoning of polar autotransporters in shigella.autotransporters are outer membrane proteins that are widely distributed among gram-negative bacteria. like other autotransporters, the shigella autotransporter icsa, which is required for actin assembly during infection, is secreted at the bacterial pole. in the bacterial cytoplasm, icsa localizes to poles and potential cell division sites independent of the cell division protein ftsz. to identify bacterial proteins involved in the targeting of icsa to the pole in the bacterial cytoplasm, we sc ...200919684128
protective role of mouse mbl-c on intestinal mucosa during shigella flexneri invasion.mannan-binding lectin (mbl) is a c-type serum lectin, which is believed to play an important role in the innate immunity against a variety of pathogens. mbl can bind to sugar determinants of a wide variety of microorganisms, neutralize them and inhibit infection by complement activation through the lectin pathway and opsonization by collectin receptors. given that small intestine is a predominant site of extrahepatic expression of mbl, here we addressed the question whether mbl is involved in mu ...200919684159
review article: anti-inflammatory mechanisms of action of saccharomyces boulardii.saccharomyces boulardii, a well-studied probiotic, can be effective in inflammatory gastrointestinal diseases with diverse pathophysiology, such as inflammatory bowel disease (ibd), and bacterially mediated or enterotoxin-mediated diarrhoea and inflammation.200919706150
purification and characterization of an immunogenic outer membrane protein of shigella flexneri 2a.in the present study we purified 34 kda major outer membrane protein (momp) of shigella flexneri 2a for the first time, which was cross-reactive and antigenically conserved among shigella spp. and the epitope was surface exposed on the intact bacterium. the purified antigen was found to be glycosylated, which aids in binding to macrophages and up-regulated the production of nitric oxide, granulocyte-colony stimulating factor and il-12p70, indicating that the momp is immunogenic and has the abili ...200919660587
screening, purification, and identification of the enzyme producing n-(l-alpha-l-aspartyl)-l-phenylalanine methyl ester from l-isoasparagine and l-phenylalanine methyl ester.screening was carried out for microorganisms able to produce n-(l-alpha-l-aspartyl)-l-phenylalanine methyl ester [apm] from l-isoasparagine and l-phenylalanine methyl ester hydrochloride. of the 422 strains examined, 44 strains belonging to the family enterobacteriaceae were found to produce apm. the enzyme catalyzing apm production was purified and identified as dipeptidase e.200919664550
an outbreak of shigella dysenteriae in sweden, may-june 2009, with sugar snaps as the suspected source.we report an outbreak of shigella dysenteriae type 2 infections during may-june 2009 in sweden, involving 47 suspected cases of whom 35 were laboratory-confirmed. the epidemiological investigation based on interviews with the patients pointed at sugar snaps from kenya as the source. shigella was not detected in samples of sugar snaps. however, escherichia coli was confirmed in three of four samples indicating contamination by faecal material. during april to may 2009 outbreaks with shigella conn ...200919607782
nonculturable response of animal enteropathogens in the agricultural environment and implications for food safety.concerns about animal enteropathogen contamination of fresh horticultural products have,increased worldwide and are mainly due to the ability of bacteria to survive under stress conditions in the agricultural environment and during raw-vegetable processing. this review challenges the idea that the viable but nonculturable phenomenon that has been proven to occur in plant-associated environments contributes to human pathogen survival and might be correlated with foodborne infection. factors assoc ...200919610353
high frequency of hotspot mutations in core genes of escherichia coli due to short-term positive selection.core genes comprising the ubiquitous backbone of bacterial genomes are not subject to frequent horizontal transfer and generally are not thought to contribute to the adaptive evolution of bacterial pathogens. we determined, however, that at least one-third and possibly more than one-half of the core genes in escherichia coli genomes are targeted by repeated replacement substitutions in the same amino acid positions-hotspot mutations. occurrence of hotspot mutations is driven by positive selectio ...200919617543
structural insights into host gtpase isoform selection by a family of bacterial gef mimics.the escherichia coli type iii effector map belongs to a large family of bacterial virulence factors that activate host rho gtpase signaling pathways through an unknown molecular mechanism. here we report direct evidence that map functions as a potent and selective guanine-nucleotide exchange factor (gef) for cdc42. the 2.3-a structure of the map-cdc42 complex revealed that map mimics the gef strategy of the mammalian dbl family but has a three-dimensional architecture that is nearly identical to ...200919620963
[virulence factors and in vitro susceptibility of plesiomonas shigelloides isolated from diarrhea episodes in cuba].acute diarrhea is still one of the main causes of disease in developing countries. at the national reference laboratory for acute diarrhoeal diseases, of the "pedro kourí" tropical medicine institute, 54 plesiomonas shigelloides strains were serotyped. as a result, the circulation of four new serotypes (o20:h2, 056:h18, 071 :h31,081 :h22) was detected. the most common antigenic variant was 094:h3. in addition, the susceptibility pattern to 21 antimicrobial agents (aa) was studied. highest percen ...200919621156
improvement of an acid phosphatase/dhap-dependent aldolase cascade reaction by using directed evolution.to enhance the phosphorylating activity of the bacterial nonspecific acid phosphatase from salmonella enterica ser. typhimurium lt2 towards dihydroxyacetone (dha), a mutant library was generated from the native enzyme. three different variants that showed enhanced activity were identified after one round of eppcr. the single mutant v78l was the most active and showed an increase in the maximal dhap concentration to 25 % higher than that of the wild-type enzyme at ph 6.0. this variant is 17 times ...200919623595
[isolation and study of perspective probiotic strain of spore-forming bacteria from bacillus genus].to study physiologic, biochemical as well as antagonistic characteristics of isolated strain of bacillus pumilus in comparison with known spore-forming bacteria from b. subtilis species.200919623717
[etiology of acute enteric infection in children with arid zone and effect of probiotics].to study etiologic structure of acute enteric infections (aei) with isolation of hemolytic and enteropathogenic escherichia and to assess the efficacy of probiotic therapy during infections caused by e. coli.200919623719
[rapid detection of salmonella in food by using fluorescently labeled phage o-i].to develop a rapid detection method for salmonella in food by using specific salmonella-phage o-i.200919623962
an integrative approach combining noncovalent mass spectrometry, enzyme kinetics and x-ray crystallography to decipher tgt protein-protein and protein-rna interaction.the trna-modifying enzyme trna-guanine transglycosylase (tgt) is a putative target for new selective antibiotics against shigella bacteria. the formation of a tgt homodimer was suggested on the basis of several crystal structures of tgt in complex with rna. in the present study, noncovalent mass spectrometry was used (i) to confirm the dimeric oligomerization state of tgt in solution and (ii) to evidence the binding stoichiometry of the complex formed between tgt and its full-length substrate tr ...200919627989
enterohaemorrhagic escherichia coli serogroup o111 inhibits nf-(kappa)b-dependent innate responses in a manner independent of a type iii secreted ospg orthologue.enterohaemorrhagic and enteropathogenic escherichia coli (ehec and epec) inject a repertoire of effector proteins into host cells via a type iii secretion system (t3ss) encoded by the locus of enterocyte effacement (lee). ospg is an effector protein initially identified in shigella that was shown to inhibit the host innate immune response. in this study, we found ospg homologues in ehec (mainly of serogroup o111) and in yersinia enterocolitica. the t3ss encoded by the lee was able to inject thes ...200919628559
differentiation of whole bacterial cells based on high-throughput microarray chip printing and infrared microspectroscopic readout.using robotic automation, a microarray printing protocol for whole bacterial cells was developed for subsequent label-free and nondestructive infrared microspectroscopic detection. using this contact microspotting system, 24 microorganisms were printed on zinc selenide slides; these were 6 species of listeria, 10 species of vibrio, 2 strains of photobacterium damselae, yersinia enterocolitica 289, bacillus cereus atcc 14529, staphylococcus aureus, atcc 19075 (serotype 104 b), shigella sonnei 201 ...200919630511
[development of single base extension-tags microarray for the detection of food-borne pathogens].we developed single base extension-tags (sbe-tags) microarray to detect eight common food-borne pathogens, including staphylococcus aureus, vibrio parahaemolyticus, listeria monocytogenes, salmonella, enterobacter sakazaki, shigella, escherichia coli o157:h7 and campylobacter jejuni. with specific pcr primers identified and integrated for eight food-borne pathogens, target sequences were amplified and purified as template dna of single base extension-tags reaction. the products were hybridized t ...200919637631
vaccination of children in low-resource countries against shigella is unlikely to present an undue risk of reactive arthritis.shigellosis is a major cause of morbidity and mortality among children in low-resource countries. promising vaccine strategies in development include genetically attenuated shigella, killed whole cell vaccines, subcellular vaccines, and o-polysaccharide-protein conjugates. there is a concern that shigella vaccines could either induce reactive arthritis or could prime vaccinees for arthritis after a subsequent exposure to the pathogen because shigellosis is associated with reactive arthritis, esp ...200919643213
physicochemical, nutritional and antibacterial characteristics of the fruit of bromelia pinguin l.bromelia pinguin l. is a plant native to sinaloa, mexico, where its fruit is used as food or as a phytotherapeutic agent. the fruits of b. pinguin were characterized and they could be considered as a functional food. these fruits show an average weight of 13.7 g and a yellow color of high luminosity (b* = 43.2, l* = 74.5). the values for acidity (4.6%, as citric acid) and ph (3.7) of b. pinguin fruit are similar to those of citrics. the edible portion is characterized by a high content of vitami ...200919536651
a similarity in the o-acetylation pattern of the o-antigens of shigellaflexneri types 1a, 1b, and 2a.shigella flexneri type 2a is the first, and type 1b is the second, most prevalent isolates from patients with shigellosis in russia. the o-specific polysaccharides (opss, o-antigens) of s. flexneri types 1-5 possess a common -->2)-alpha-l-rhapiii-(1-->2)-alpha-l-rhapii-(1-->3)-alpha-l-rhapi-(1-->3)-beta-d-glcpnac-(1--> backbone and differ from each other in its glucosylation or/and o-acetylation at various positions, the modifications being responsible for various o-factors. it was suggested tha ...200919246033
rapid emergence of third generation cephalosporin resistant shigella spp. in southern vietnam. 200919141753
giardia duodenalis assemblages associated with diarrhea in children in south india identified by pcr-rflp.giardial diarrhea in a birth cohort of 452 children in an urban slum in south india was characterized. of the 155 episodes that occurred in 99 children, 73% were acute diarrhea. children with better educated mothers and a toilet at home had lower odds of acquiring giardial diarrhea, whereas low socioeconomic status and drinking municipal water were associated with greater risk. children with co-infections tended to have a slightly longer duration of diarrhea (p = 0.061) and showed significantly ...200919141832
improvement in detection of enterotoxigenic escherichia coli in patients with travelers' diarrhea by increasing the number of e. coli colonies tested.no cause of one-third of travelers' diarrhea (td) cases can be detected despite microbiologic assessment. we propose that these pathogen-negative td cases include undetected enterotoxigenic escherichia coli (etec). as a standard in diagnostic microbiology, samples of five e. coli colonies were tested to detect etec from stool cultures. we compared the sensitivities and the number of etec detected by 20 colonies with those of 5, 10, and 15 colonies. the percent detection of etec with five e. coli ...200919141833
septins regulate bacterial entry into host cells.septins are conserved gtpases that form filaments and are required in many organisms for several processes including cytokinesis. we previously identified sept9 associated with phagosomes containing latex beads coated with the listeria surface protein inlb.200919145258
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