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shigella lipopolysaccharide antibodies in pediatric populations.shigellosis is the most common cause of bacterial dysentery. to study the specific immunity to the two major groups causing shigellosis, we assayed antibodies to lipopolysaccharide (lps) by enzyme-linked immunoadsorbent assay to both shigella sonnei and shigella flexneri 2a serotypes in the following populations: (1) women immediately after delivery and their infants to assess the transfer of passive immunity by placenta and the presence of secretory antibodies in breast milk; (2) children of di ...19958584312
evaluation of giardeia kit for giardiasis diagnosis.giardia lamblia is recognized as one of the most common agents for diarrhea world wide. to date, microscopical examination of stool samples is the gold standard for giardiasis diagnosis. however, intermittence of the giardia cycle and some medications may cause temporary disappearance of cysts from stools, thus giving false negative results. in the present study, we evaluated a commercially available enzyme immunoassay kit (giardeia) for the detection of giardia copro-antigens and compared the r ...19958586858
[species and serovar-distribution, and drug-resistance of shigella strains isolated from imported and domestic cases from 1990 through 1994 in tokyo].a total of 446 shigella strains consisting of 336 imported and 110 domestic strains isolated in tokyo from 1990 to 1994 were examined for their species and serovar-distribution, and their drug-resistance. in both imported and domestic strains, s. sonnei was found to be the most prevalent species, followed by s. flexneri. in imported strains, however, the isolation frequency of s. flexneri, s. boydii and s. dysenteriae were higher than that of domestic strains, and the serovar of each species was ...19958586884
the novel nuclear gene dss-1 of saccharomyces cerevisiae is necessary for mitochondrial biogenesis.a previously unknown nuclear gene dss-1 from saccharomyces cerevisiae was cloned and sequenced. the gene was isolated as a multicopy suppressor of a disruption of the suv-3 gene coding for a dead/h box protein involved in processing and turnover of mitochondrial transcripts. the dss-1 gene codes for a 970 amino-acid protein of molecular weight 111 kda and is necessary for mitochondrial biogenesis. amino-acid sequence analysis indicates the presence of motifs characteristic for escherichia coli r ...19958590460
expression of flagella and motility by shigella.since the discovery of shigella as the aetiologic agent of acute dysentery almost 100 years ago, this organism has been described as a non-motile and nonflagellated organism that invades the human colonic mucosa. in this study, the production of flagella by prototypic strains of all four shigella species and, moreover, by fresh clinical isolates was demonstrated by electron microscopy. the flagellum of shigella (flash) is approximately 10 microns long and 12-14 nm in diameter and is typically se ...19958596461
mxig, a membrane protein required for secretion of shigella spp. ipa invasins: involvement in entry into epithelial cells and in intercellular dissemination.entry of shigella flexneri into epithelial cells involves secretory proteins, the ipa proteins, and their dedicated secretion apparatus, the mxi-spa translocon, which is encoded by the mxi and spa operons. we have characterized the mxig gene that is located at the proximal part of the mxi operon. inactivation of mxig abolished lpa secretion, which indicates that mxig is an essential component of the mxi-spa translocon. immunoblotting analysis of membrane fractions suggests that the 42 kda mxig p ...19958559065
microbiological investigation of diarrhoea epidemics among rwandan refugees in zaire. 19958560524
serotype distribution and antimicrobial susceptibility of shigellae isolated from diarrhoeal patients in yangon, myanmar.in myanmar there is a changing pattern in the prevalence of shigella strains with an increasing antimicrobial resistance, and, thus the serotype prevalence and antibiotic sensitivity pattern of shigellae were studied in 1993. dysenteric stool samples were collected from the laboratory of infectious diseases hospital, yangon during january-june 1993. the shigella isolates were identified by the standard bacteriologic procedures. four hundred and sixty stool samples containing blood and mucous wer ...19958568195
immunogenicity of the shigella flexneri serotype y (sfl 124) vaccine strain expressing cloned glucosyl transferase gene of converting bacteriophage sfx.the glucosyl transferase gene (gtr) from bacteriophage phage x (sfx) caused partial conversion of serotype y (group antigen 3, 4) to x (group antigen 7, 8) when introduced into a candidate vaccine strain of shigella flexneri serotype y (sfl124). the gtr gene caused conversion of o-antigens but did not eliminate the adsorption of the corresponding phage sfx. the hybrid strain expressing both group antigens 7, 8 and 3, 4 showed 75% protection when immunized guinea pigs were challenged with a wild- ...19958569531
adherence of helicobacter pylori to cultured human gastric carcinoma cells.to examine the binding activity of helicobacter pylori to cultured gastric epithelial cells using flow cytometry.19958574746
serum antibody to lipopolysaccharide antigens of shigella species among u.s. military personnel deployed to saudi arabia and kuwait during operations desert shield and desert storm.during operations desert shield and desert storm, u.s. troops were at high risk of diarrheal disease due to shigella spp., particularly shigella sonnei. in order to better understand the serologic response to shigella infection, 830 male u.s. combat troops were evaluated before and after the deployment to saudi arabia and kuwait for immunoglobulin a (iga) and igg anti-shigella lipopolysaccharide (lps) (antibody to s. sonnei form i and shigella flexneri serotypes 1a, 2a, and 3a) in serum. just be ...19958574833
[the selection of a virulent subpopulation of escherichia coli during shigella and salmonella infections in children]. 19958553728
[the antigenic and immunogenic properties of the bivalent strain shigella flexneri-shigella sonnei 1 no. 200]. 19958553752
identification of two targets of the type iii protein secretion system encoded by the inv and spa loci of salmonella typhimurium that have homology to the shigella ipad and ipaa proteins.an important virulence factor of salmonella spp. is their ability to gain access to host cells. a type iii secretion system encoded in the inv and spa loci of these organisms is essential for this phenotype. we have identified two proteins, sipa and sipd, whose secretion from the bacterial cells is dependent on this system. the genes encoding these proteins are located at centisome 63 on the s. typhimurium chromosome, immediately downstream of the previously identified sipb and sipc genes (k. ka ...19958522512
use of plasma desorption mass spectrometry in structural analysis of endotoxins: effects on lipid a of different acid treatments. 19958524917
biological properties of yolk immunoglobulins. 19958526019
identification and sequences of the treponema pallidum flim', fliy, flip, fliq, flir and flhb' genes.information regarding the biology and virulence attributes of treponema pallidum (tp) is limited due to the lack of genetic exchange mechanisms and the inability to continuously cultivate this spirochete. we have utilized tnphoa mutagenesis of a tp genomic dna library in escherichia coli (ec) to identify genes encoding exported proteins, a subset of which are likely to be important in treponemal pathogenesis. we report here the identification and nucleotide (nt) sequence of a 5-kb treponemal dna ...19958529894
viral diarrhoea in a rural coastal region of karnataka india.a total of 106 children below 5 years of age admitted to the kasturba medical college hospital manipal karnataka (south india) were investigated over a period of 6 months to determine the aetiological role of viruses in acute diarrhoea. viral aetiological agents isolated were rotaviruses in 12 (11 per cent) cases, adenoviruses in 3 (3 per cent) cases, coronavirus and astroviruses in two (2 per cent) cases each. non-viral isolates were cryptosporidium and salmonella typhimurium in two cases each, ...19958531264
shigellosis in children from north india: a clinicopathological study.stool samples of 1488 children suffering from acute diarrhoea were studied for bacterial culture and sensitivity. shigella culture was positive in 143 (10 per cent) children and 53 hospitalized children could be studied in detail. thirty-six (68 per cent) children were under 2 years of age and peak prevalence was observed in summer months. fever and diarrhoea were universal features; 96 per cent had blood and mucus in the stools, but 32 per cent started with watery diarrhoea lasting 1-3 days fol ...19958531265
extracellular transport of virg protein in shigella.the ability of shigella to spread within and between epithelial cells is a prerequisite for causing bacillary dysentery and requires the function encoded by the virg gene on the large plasmid. the outer membrane virg (icsa) protein is essential for bacterial spreading by eliciting polar deposition of filamentous actin (f-actin) in the cytoplasm of epithelial cells. recent studies have indicated that an n-terminal 80-kda virg portion is exposed on the bacterial cell surface and released into the ...19958537341
partial dna sequence of a beta-lactamase produced by a shigella flexneri strain.a probe was constructed by radioactive labelling, and enzymatically a dna fragment of plasmid pmam-1, which codes for a beta-lactamase in shigella flexneri ucsm 129, was obtained by amplification of a small part of the gene using the polymerase chain reaction technique (pcr). since previous published work indicated that this beta-lactamase was of the tem type, the primers used to amplify the gene were two highly conserved dna regions in all tem beta-lactamases. a 500 bp dna probe was obtained wh ...19958538491
population dynamics in the co-culture of shigella flexneri 1b original strain and its antigenic 3b mutant carrying a prophage.the antigenic mutant shigella flexneri 3b showed selective prevalence when subcultured with the original strain 1b. mathematical analysis of such co-cultures showed that the dynamics of bacterial growth may be described by equations of the lotka-volterra type. the analysis of serial cultivations suggests that parameters of the equations may be realizations of random variables characterizing strains and media. the mutant carries a prophage lethal for the original strain. distinctive features of t ...19958538494
serological identification of shigella flexneri strains by the coagglutination reaction.several variants of reagents were prepared by coupling type (i, ii iii, iv, v and vi) and group (3, 4, 6 and 7, 8, 9) anti-shigella flexneri sera with protein a--containing staphylococcal suspension. for most serum lots coagglutination led to a 1/10 minimum dilution. however, different efficiencies were reported between serum lots and even within the same type or group. no improvement by the coagglutination reaction could be obtained for one lot from group 3, 4 and 7, 8, 9 sera and for both type ...19958993123
a transferable multiple drug resistance plasmid from vibrio cholerae o1.ten multiple antimicrobial-resistant isolates of vibrio cholerae o1 isolated from patients in uganda were characterized, and the transferability of resistance to bacteria of diverse origins was investigated. the isolates were toxigenic and belonged to biotype e1 tor, serotype ogawa, and ribotype 8, and possessed a 130-mda plasmid of incompatibility group 6-c. this plasmid, designated prvc1, was shown to confer resistance to trimethoprim (mediated by a dhfri gene), sulfonamides (a suii gene), tet ...19959158776
[the use of non-euclidean metrics in epidemiological classifications].a non-euclidean metric, stable to pollutions in sample data, for hierarchical cluster analysis in epidemiology is proposed. the simplicity of calculations permits its easy use in practice. on the basis of this metric the towns of tula province have been grouped according to morbidity rates in the shigellosis of flexner and sonne with the conjugated value of parameters.19959381873
[pathogenicity of shigella flexneri and its regulation]. 19957474338
sepa, the major extracellular protein of shigella flexneri: autonomous secretion and involvement in tissue invasion.in addition to ipa proteins and icsa, which are involved in entry into epithelial cells and intercellular spread, respectively, shigella secretes a 110 kda protein, designated sepa. we report the identification, cloning, and nucleotide sequence determination of the sepa gene, analysis of sepa secretion, and construction and characterization of a sepa mutant. the sepa gene is carried by the virulence plasmid and codes for a 150 kda precursor. upon secretion, which does not involve accessory prote ...19957476198
phop/phoq transcriptional repression of salmonella typhimurium invasion genes: evidence for a role in protein secretion.previously, the phop-repressed locus prgh was identified as important for signalling epithelial cells to endocytose salmonella typhimurium. characterization of prgh revealed that it is an operon of four genes encoding polypeptides of 392 (prgh), 80 (prgi), 101 (prgj) and 252 amino acid residues (prgk). synthesis of the 2.6 kb prghijk transcript was repressed in bacteria that activate phop/phoq, indicating that phop/phoq regulates prghijk by transcriptional repression. the prgi, prgj and prgk pre ...19957476203
use of confocal microscopy in studying bacterial adhesion and invasion. 19957476384
n-terminal amino-acid sequence of beta-lactamase from shigella flexneri ucsf-129.a beta-lactamase (ec 3.5.2.6 penicillinase, penicillin amino beta-lactam-hydrolase) was purified from shigella flexneri uscf-129 by an efficient two-stage procedure involving chromatography in sephadex g-75 and hplc on a c18-reverse phase column. the homogeneity of the purified enzyme was confirmed by capillary zone electrophoresis (cze), hplc electrospray mass spectrometry (lc-esms) and amino acid sequence analyses. the highly purified enzyme was a monomeric protein with a molecular mass of 28. ...19957476560
antigenic variability of shigella flexneri serovars 1-5.data on the genetic basis of the classification of shigella flexneri serological variants 1-5 are presented. subserovars "a" are related to monolysogenic variants of the basic lipopolysaccharide (lps) structure 0 antigen 3,4, "b" to bilysogenic ones. a scheme of their antigenic variability, with regard to loss of one or both prophages is presented. this scheme helps differentiate between antigenic variability and mixed or superinfections. recent reports confirming our previously published sugges ...19957477027
outbreak of shigella flexneri linked to salad prepared at a central commissary in michigan.in august 1992, the michigan department of public health was notified of a cluster of persons with shigella flexneri infections, all of whom had eaten at different outlets of a single restaurant chain. the chain prepared many foods at a central kitchen. a matched case-control study to determine risk factors for illness among patrons of the restaurant chain was undertaken. an inspection of the commissary and a review of commissary inspection and employee records were conducted. of the 46 patients ...19957480612
invasion of epithelial cells by shigella flexneri induces tyrosine phosphorylation of cortactin by a pp60c-src-mediated signalling pathway.shigella flexneri causes bacillary dysentery in humans by invading epithelial cells of the colon. cell invasion occurs via bacterium-directed phagocytosis, a process requiring polymerization of actin at the site of bacterial entry. we show that invasion of hela cells by s.flexneri induces tyrosine phosphorylation of cortactin, a host cell protein previously identified as a cytoskeleton-associated protein tyrosine kinase (ptk) substrate for the proto-oncoprotein pp60c-src. immunolocalization expe ...19957540134
structural elucidation of the o-antigen lipopolysaccharide from two strains of plesiomonas shigelloides that share a type-specific antigen with shigella flexneri 6, and the common group 1 antigen with shigella flexneri spp and shigella dysenteriae 1.sugar and methylation analyses of native polysaccharides together with one-dimensional 1h- and 13c-nmr spectroscopy revealed that the two polysaccharides from strains 22074 and 12254 of plesiomonas shigelloides are identical. the structure of the polysaccharide from strain 22074 was deduced from a uronic acid degradation and by nmr spectroscopy where heteronuclear multiple bond connectivity and two-dimensional nuclear overhauser effect spectroscopy experiments established the pentasaccharide rep ...19957544287
monoclonal immunoglobulin a antibody directed against serotype-specific epitope of shigella flexneri lipopolysaccharide protects against murine experimental shigellosis.to determine the role of humoral mucosal immune response in protection against shigellosis, we have obtained a monoclonal dimeric immunoglobulin a (iga) antibody specific for shigella flexneri serotype 5a lipopolysaccharide (miga) and used a murine pulmonary infection model that mimics the lesions occurring in natural intestinal infection. adult balb/c mice challenged with 10(7) s. flexneri organisms developed a rapid inflammatory response characterized by polymorphonuclear cell infiltration aro ...19957544397
expression of shigella dysenteriae serotype 1 o-antigenic polysaccharide by shigella flexneri arod vaccine candidates and different s. flexneri serotypes.the potential utility of shigella flexneri arod vaccine candidates for the development of bi- or multivalent vaccines has been explored by the introduction of the genetic determinants rfp and rfb for heterologous o antigen polysaccharide from shigella dysenteriae serotype 1. the serotype y vaccine strain sfl124 expressed the heterologous antigen qualitatively and quantitatively well, qualitatively in the sense of the o antigen polysaccharide being correctly linked to the s. flexneri lipopolysacc ...19957545156
live attenuated shigella flexneri mutants as vaccine candidates against shigellosis and vectors for antigen delivery.up to now, no effective vaccine is available against shigellosis, a dysenteric syndrome caused by shigella, a gram-negative bacterium which invades the human colonic mucosa. about 40 years of research in the field have led to the conclusion that orally administered live shigella vaccine strains are more effective in eliciting protection than killed bacteria given parenterally. recently, the construction of promising new live attenuated vaccines has come with a better understanding of the fundame ...19957546655
[the resistance to antibiotics and chemotherapeutic agents of shigella strains isolated from hiv-seropositive children]. 19957549258
functional conservation of the secretion and translocation machinery for virulence proteins of yersiniae, salmonellae and shigellae.virulent bacteria of the genera yersinia, shigella and salmonella secrete a number of virulence determinants, yops, ipas and sips respectively, by a type iii secretion pathway. the ipab protein of shigella flexneri was expressed in yersinia pseudotuberculosis and found to be secreted under the same conditions required for yop secretion. likewise, yope was secreted by the wild-type strain lt2 of salmonella typhimurium, but yope was not secreted by the isogenic inva mutant. secretion of both ipab ...19957556059
recognition of three epitopic regions on invasion plasmid antigen c by immune sera of rhesus monkeys infected with shigella flexneri 2a.the invasive ability of shigella spp. is correlated with the expression of several plasmid-encoded proteins, including invasion plasmid antigen c (ipac). by characterizing the antigenic structure of ipac with monoclonal antibodies and convalescent-phase sera, it may be possible to determine the physical location of specific epitopes as well as the involvement of epitopes in a protective immune response or the host's susceptibility to disease. by using overlapping octameric synthetic peptides, wh ...19957558301
evaluation of commercial antisera for shigella serogrouping.shigella serogrouping antisera from six companies (becton dickinson, denka, difco, murex, roach, and sanofi-pasteur) intended for the slide agglutination test and those of the wellcolex colour shigella latex agglutination test were evaluated to identify quality products for shigella identification. forty-six reference shigella strains (one for each serotype and species), 50 clinical strains (21 s. flexneri, 21 s. sonnei, 4 s. dysenteriae, 4 s. boydii) representing the most prevalent species and ...19957559936
comparison of preservation media for storage of stool samples.transportation of clinical samples and long-term recoverability of pathogens are critical to epidemiological studies, particularly when conditions do not permit immediate processing. this study confirms that cary-blair medium (cb) is suitable for the preservation of salmonella and shigella isolates for more than 2 weeks at 25, 4, or -70 degrees c. campylobacter jejuni was not recovered after 2 days of storage in cb at 25 degrees c when an inoculum of 12 x 10(8) cells per ml was used. lower tempe ...19957559972
enhanced secretion through the shigella flexneri mxi-spa translocon leads to assembly of extracellular proteins into macromolecular structures.genes required for entry of shigella flexneri into epithelial cells in vitro are clustered in two adjacent loci, one of which encodes secretory proteins, the ipaa-d proteins, and the other their dedicated secretion apparatus, the mxi-spa translocon. ipa secretion, which is induced upon contact of bacteria with epithelial cells, is prevented during growth in vitro. here, we show that ipab and ipad mutations lead to enhanced secretion of a set of about 15 proteins. these extracellular proteins and ...19957565091
attenuated shigella as a dna delivery vehicle for dna-mediated immunization.direct inoculation of dna, in the form of purified bacterial plasmids that are unable to replicate in mammalian cells but are able to direct cell synthesis of foreign proteins, is being explored as an approach to vaccine development. here, a highly attenuated shigella vector invaded mammalian cells and delivered such plasmids into the cytoplasm of cells, and subsequent production of functional foreign protein was measured. because this shigella vector was designed to deliver dna to colonic mucos ...19957569980
structural analysis of invasion plasmid antigen d (ipad) from shigella flexneri.invaison plasmid antigen d (ipad) and water-extracted outer-membrane proteins (omps) from shigella flexneri were used to investigate some of the structural relationships of this pathogen's invasions. extracellular presentation of the three invasion plasmid antigens (ipa) b, c, and d is required for the s. flexneri invasive phenotype; however, little is known of the structural properties of these essential virulence components. biochemical data suggest ipab, c, and d present in s. flexneri omps f ...19957575570
the complete hrp gene cluster of pseudomonas syringae pv. syringae 61 includes two blocks of genes required for harpinpss secretion that are arranged colinearly with yersinia ysc homologs.pseudomonas syringae pv. syringae 61 contains a 25-kb hrp cluster that is sufficient to elicit the hypersensitive response (hr) in nonhost plants. previous studies have shown that mutations in complementation groups viii, ix, and xi in the hrp cluster abolished the ability of the bacterium to cause the hr. the sequence of a 3.7-kb smai-ssti fragment covering groups viii and ix now reveals five open reading frames (orfs) in the same transcript, designated as hrpu, hrpw, hrpo, hrpx, and hrpy, and ...19957579617
sequence and analysis of the o antigen gene (rfb) cluster of escherichia coli o111.the o antigens found in salmonella enterica (se) and escherichia coli (ec) show a great deal of diversity, and only three structures are known to be common to both genera. two of them contain the 3,6-dideoxyheoxse colitose, not found in other serogroups of the two species. the first of these is common to ec o111 and se o:35 (sv adelaide); the other is found in both ec o55 and se o:50 (sv greenside). the genes specific for the synthesis of o antigen are generally located in the rfb gene cluster a ...19957590310
development of an improved animal model of shigellosis in the adult rabbit by colonic infection with shigella flexneri 2a.rabbits are not usually susceptible to intestinal shigella infection without extensive pretreatment, including starvation and administration of antimicrobial, antimotility, and toxic agents (carbon tetrachloride). most animals infected this way die rapidly and do not always develop colonic lesions and signs of dysentery. we describe here a successful experimental infection in the adult rabbit which does not require preparatory treatment and which reproduced characteristic features of human shige ...19957591070
identification and cloning of a novel plasmid-encoded enterotoxin of enteroinvasive escherichia coli and shigella strains.we have employed a molecular genetic approach to characterize the nature of enteroinvasive escherichia coli (eiec) enterotoxic activity, as previously observed in ussing chambers (a. fasano, b.a. kay, r.g. russell, d.r. maneval, jr., and m.m. levine, infect. immun. 58:3717-3723, 1990). the screening of tnphoa mutants of eiec yielded a single insertion mutant which had significantly reduced levels of enterotoxic activity in the ussing chamber assay. dna flanking the insertion was used as a probe ...19957591128
prevalence of shigella enterotoxin 1 among shigella clinical isolates of diverse serotypes.shigella enterotoxin 1 (shet1) is a novel, iron-dependent, toxin encoded by chromosomal genes (set1). to determine the prevalence of this enterotoxin, 172 shigella clinical isolates (and 10 enteroinvasive escherichia coli [eiec]) from distant areas worldwide, representing all 4 groups and 45 serotypes of shigella, were screened for set1 by dna colony hybridization and polymerase chain reaction amplification. set1 was present in all 22 shigella flexneri 2a strains tested but was rare in isolates ...19957594690
shigella flexneri surface protein icsa is sufficient to direct actin-based motility.shigella flexneri is a gram-negative bacterial pathogen that can grow directly in the cytoplasm of infected host cells and uses a form of actin-based motility for intra- and intercellular spread. moving intracellular bacteria are associated with a polarized "comet tail" composed of actin filaments. icsa, a 120-kda outer membrane protein necessary for actin-based motility, is located at a single pole on the surface of the organism, at the junction with the actin tail. here, we demonstrate that st ...19957604035
cell movement tale told by bacterial tail protein. 19957604275
comparative analysis of extreme acid survival in salmonella typhimurium, shigella flexneri, and escherichia coli.several members of the family enterobacteriaceae were examined for differences in extreme acid survival strategies. a surprising degree of variety was found between three related genera. the minimum growth ph of salmonella typhimurium was shown to be significantly lower (ph 4.0) than that of either escherichia coli (ph 4.4) or shigella flexneri (ph 4.8), yet e. coli and s. flexneri both survive exposure to lower ph levels (2 to 2.5) than s. typhimurium (ph 3.0) in complex medium. s. typhimurium ...19957608084
shigella flexneri adherence to and multiplication in coxsackie b1 virus-infected hep-2 cells.coxsackie b1 virus infection enhances the susceptibility of in vitro cultured hep-2 cells to invasiveness by shigella flexneri. we have studied the effect of viral infection on two phases of the invasiveness. only a minor part was mediated by enhanced bacterial adherence to the cells, and the intracellular multiplication was unaffected by the virus. enhanced adherence was not dependent on the presence of the gene product of the 140 md virulence associated plasmid. our data indicate that enhanced ...19957612255
[the colicin selection of the s forms of representatives in the enterobacteriaceae family].a method based on a lower sensitivity of s forms to colicines, in comparison with r forms, was used for the selection of s forms of bacteria from dissociated cultures of e. coli o.124:k72, s. sonnei, and s. flexneri. the cultures are inoculated in nutrient agar from the external segment of the zone of bacterial growth suppression by colicines d, e1, and v+m, where the content of s forms is relatively higher at the expense of death of r forms. the content of s forms in the resultant cultures of d ...19957620780
shigella infection induces cellular activation of t and b cells and distinct species-related changes in peripheral blood lymphocyte subsets during the course of the disease.immunophenotypic changes in peripheral blood lymphocytes (t, b, and nk cells) in patients during shigellosis was characterized by using triple-color flow cytometry. eleven shigella dysenteriae 1-infected adult patients (sdip), 11 shigella flexneri-infected adult patients (sfip), 15 age- and sex-matched healthy controls from bangladesh (c-b), and 15 healthy volunteers from sweden (v-s) were studied. in sdip and sfip, a significant increase in the cd45ro+ cells in both cd4+ and cd8+ t cells were s ...19957622216
the hrp gene locus of pseudomonas solanacearum, which controls the production of a type iii secretion system, encodes eight proteins related to components of the bacterial flagellar biogenesis complex.five transcription units of the pseudomonas solanacearum hrp gene cluster are required for the secretion of the hr-inducing popa1 protein. the nucleotide sequences of two of these, units 1 and 3, have been reported. here, we present the nucleotide sequence of the three other transcription units, units 2, 4 and 7, which are together predicted to code for 15 hrp genes. this brings the total number of hrp proteins encoded by these five transcription units to 20, including hrpb, the positive regulat ...19957623665
virg, a yersinia enterocolitica lipoprotein involved in ca2+ dependency, is related to exsb of pseudomonas aeruginosa.pathogenic yersiniae require ca2+ for growth at 37 degrees c. they harbor closely related plasmids of about 70 kb that are essential for virulence. at 37 degrees c and in the absence of ca2+ ions, these plasmids cause a decrease in growth rate and the release of large amounts of proteins called yops. here we describe the virg gene of yersinia enterocolitica; virg is located just upstream of the virf gene, which encodes the transcriptional activator of some plasmid virulence factors. analysis of ...19957635810
role of interleukin-1 in the pathogenesis of experimental shigellosis.the effect of human recombinant interleukin-1 receptor antagonist on intestinal inflammation, tissue destruction, and bacterial invasion during experimental shigellosis caused by shigella flexneri was studied in the rabbit-ligated loop infection model. intravenous infusion of the inhibitor at a dose of 2 mg/kg per h, was initiated 30 min before intestinal loops were ligated and infected, and continued during the 8-h period of infection. the animals treated with il-1 receptor antagonist showed a ...19957635983
evaluation of the safety, immunogenicity, and efficacy in healthy adults of four doses of live oral hybrid escherichia coli-shigella flexneri 2a vaccine strain ecsf2a-2.in previous trials, live invasive escherichia coli-shigella flexneri 2a hybrid vaccine candidate ecsf2a-2, administered to adult volunteers as 3 doses of ca. 2 x 10(9) colony forming units (c.f.u.) spaced over one week, induced fever and/or diarrhea in 11% of subjects and provided only limited protection (36% efficacy) against illness following challenge with virulent s. flexneri 2a. we sought to improve the clinical safety of this vaccine by administering a lower inoculum, and to enhance protec ...19957639017
h-ns regulation of virulence gene expression in enteroinvasive escherichia coli harboring the virulence plasmid integrated into the host chromosome.we have previously shown that integration of the virulence plasmid pinv into the chromosome of enteroinvasive escherichia coli and of shigella flexneri makes these strains noninvasive (c. zagaglia, m. casalino, b. colonna, c. conti, a. calconi, and m. nicoletti, infect. immun. 59:792-799, 1991). in this work, we have studied the transcription of the virulence regulatory genes virb, virf, and hns (virr) in wild-type enteroinvasive e. coli hn280 and in its pinv-integrated derivative hn280/32. whil ...19957642498
enteropathogenic escherichia coli contains a putative type iii secretion system necessary for the export of proteins involved in attaching and effacing lesion formation.enteropathogenic escherichia coli (epec) causes a characteristic histopathology in intestinal epithelial cells called the attaching and effacing lesion. although the histopathological lesion is well described the bacterial factors responsible for it are poorly characterized. we have identified four epec chromosomal genes whose predicted protein sequences are similar to components of a recently described secretory pathway (type iii) responsible for exporting proteins lacking a typical signal sequ ...19957644527
252cf-plasma desorption mass spectrometry analysis of lipids a obtained by an elimination reaction under mild conditions.lipids a are the hydrophobic domains of bacterial endotoxic lipopolysaccharides. since they are responsible for most of the biological activities (both pathogenic and beneficial) of endotoxins, the characterization of their structure is crucial to the understanding of their mode of action. however, the inadequacy of existing methods for preparing certain lipids a has prompted us to devise a new, mild procedure which gives intact products. use was made of the special features of 252cf-plasma deso ...19957647366
[the immunomodulating capacity of shigella flexneri 2a bacteria that have lost their invasiveness plasmid].an immunosuppressive effect produced by live microbial cells of s. flexneri virulent plasmid-carrying strain 2a 516 (psf 140-) was shown in relation to the formation of splenic cells producing antibodies to heterologous antigen (sheep red blood cells). this effect was most pronounced at an early period (days 4-7) after the infection of mice. on the contrary, avirulent plasmid-free variant (psf 140-), genetically related to s. flexneri strain 2a 516, produced an immunostimulating effect at this p ...19957653137
epidemiological, clinical and microbiological features of shigellosis among hospitalized children in northern israel.the epidemiological, clinical, and bacteriological aspects of shigellosis were studied in a population of hospitalized children in northern israel. during the 6-year period 1987-92, 262 children were hospitalized due to shigella infection. shigellosis represented 10% of pediatric admissions for diarrhea. admissions for the disease peaked during the summer and autumn. the median age of the patients was 3 years. shigella sonnei was isolated in 74% of patients and s. flexneri in 21%, compared with ...19957660077
pivmecillinam resistant shigella infections in rural bangladesh. 19957660498
identification of a global repressor gene, rsma, of erwinia carotovora subsp. carotovora that controls extracellular enzymes, n-(3-oxohexanoyl)-l-homoserine lactone, and pathogenicity in soft-rotting erwinia spp.the production of extracellular enzymes such as pectate lyase (pel), polygalacturonase (peh), cellulase (cel), and protease (prt) is activated by the cell density (quorum)-sensing signal, n-(3-oxohexanoyl)-l-homoserine lactone (hsl); plant signals; and aep genes during postexponential growth of erwinia carotovora subsp. carotovora 71. studies with mutants of e. carotovora subsp. carotovora 71 derepressed in exoenzyme production led to the identification of a negative regulator gene, rsma (rsm, r ...19957665490
1995 flemming lecture. dna topology and the global control of bacterial gene expression: implications for the regulation of virulence gene expression. 19957670631
identification of a novel virulence gene, vira, on the large plasmid of shigella, involved in invasion and intercellular spreading.a novel virulence gene (vira) was identified upstream of the virg gene on the large plasmid of shigella flexneri 2a ysh6000. characterization of vira mutants infecting mk2 epithelial cell monolayers revealed that their invasive capacity was decreased to less than one fifth of the wild-type level. nevertheless, the bacteria were capable of expressing and secreting ipab, ipac and ipad proteins. the vira mutants were also impaired in their ability to spread intercellularly, since the bacteria gave ...19957494473
entry of microbes into the host: using m cells to break the mucosal barrier.enteric microbial pathogens interact with the gut epithelium to establish infection. recently, it has become clear that many microorganisms that colonize or traverse the intestinal mucosa do so via the specialized m cells. recent work has shown that shigella flexneri and salmonella typhimurium specifically target m cells to initiate infection of the host.19957495510
mucosal immune response in patients with dysentery. 19957502926
avirulence of rough mutants of shigella flexneri: requirement of o antigen for correct unipolar localization of icsa in the bacterial outer membrane.mutations in the lipopolysaccharide (lps) of shigella spp. result in attenuation of the bacteria in both in vitro and in vivo models of virulence, although the precise block in pathogenesis is not known. we isolated defined mutations in two genes, galu and rfe, which directly affect synthesis of the lps of s. flexneri 2a, in order to determine more precisely the step in virulence at which lps mutants are blocked. the galu and rfe mutants invaded hela cells but failed to generate the membrane pro ...19957528731
molecular, genetic, and topological characterization of o-antigen chain length regulation in shigella flexneri.the rfb region of shigella flexneri encodes the proteins required to synthesize the o-antigen component of its cell surface lipopolysaccharides (lps). we have previously reported that a region adjacent to rfb was involved in regulating the length distribution of the o-antigen polysaccharide chains (d. f. macpherson et al., mol. microbiol. 5:1491-1499, 1991). the gene responsible has been identified in escherichia coli o75 (called rol [r. a. batchelor et al., j. bacteriol. 173:5699-5704, 1991]) a ...19957532168
high frequency of strains multiply resistant to ampicillin, trimethoprim-sulfamethoxazole, streptomycin, chloramphenicol, and tetracycline isolated from patients with shigellosis in northeastern brazil during the period 1988 to 1993.the occurrence and antimicrobial resistance pattern of shigella isolates obtained from persons in community and hospital-based studies of diarrhea and matched controls in northeastern brazil were studied. the isolation rate of shigella spp. from patients with diarrhea during 1988 to 1993 varied from 4.5% (26 of 575) for the urban community of gonçalves dias to 6.7% (12 of 179) and 5.9% (7 of 119) for hospital infantil and hospital universitário, respectively. of the 55 shigella isolates (45 from ...19957695319
genetic analysis of the rfbx gene of shigella flexneri.analysis of the nucleotide sequence of the rfbx gene of shigella flexneri revealed that it contained a high proportion of rare codons, as previously observed in the analysis of the o-antigen polymerase-encoding gene rfc [morona et al., j. bacteriol. 176 (1994) 733-747]. the rfbx gene encodes a hydrophobic, 46-kda protein, with 12 potential transmembrane-spanning domains, that shows structural homology with gene products encoded in many rfb regions, and with orf0416 of the rff region of escherich ...19957698674
a conformationally homogeneous combinatorial peptide library.in search for a rational way to convert the information encoded in peptide structures into peptidomimetics, major progress could be made by coupling the power of selection methods, now enormously increased in number as a result of the development of combinatorial peptide libraries, with the rational design of structure-inducing templates for the selectable sequences. the availability of libraries of peptides with predetermined structure would enable selection-driven peptidomimetic design, whereb ...19957707366
fecal excretion of leukotriene c4 during human disease due to shigella dysenteriae.fecal excretion of leukotriene c4 was determined in 26 individuals with dysentery and in 19 healthy controls. of the patients, five were infected with shigella dysenteriae type 1, 15 were infected with shigella flexneri, two were infected with shigella boydii, and four were infected with shigella sonnei. three of the healthy controls were infected with non-dysenteriae shigellae. all isolates of shigella dysenteriae type 1 produced shiga toxin; the other strains were not toxigenic. patients with ...19957714683
cell-to-cell spread of shigella flexneri: exploitation of the host cytoskeleton. 19957714693
the pho regulon of shigella flexneri.growth of escherichia coli k-12 in low-phosphate conditions results in the induction of the synthesis of many proteins, including the outer membrane porin phoe, alkaline phosphatase, and the pst system for the transport of phosphate (p1). this response is controlled by a two-component regulatory system of which phob and phor are the response-regulator and the sensor/kinase, respectively. when shigella flexneri was starved for p1, neither phoe nor alkaline phosphatase was produced. however, induc ...19957746146
acid tolerance of enterohemorrhagic escherichia coli.enterohemorrhagic escherichia coli (ehec) strains were tested for their ability to survive in acid ph at 37 degrees c. no loss of viability was observed in an o157:h7 ehec strain (atcc 43895) at ph levels of 3.0 and 2.5 for at least 5 h. the level of acid tolerance of most ehec isolates was very high, similar to that of shigella flexneri strains. the acid tolerance was dependent on the growth phase and ph of the growth medium.19957747983
actin-based bacterial motility.listeria monocytogenes and other bacterial pathogens move in the host cell cytoplasm, propelled by continuous actin assembly at one pole of the bacterium. this actin-based motility requires the presence of the bacterial proteins acta on l. monocytogenes and icsa on shigella flexneri. there have been several major discoveries in the past year: the discovery of the polar distribution of acta and icsa on the bacterial surface; the demonstration that bacterial acta is phosphorylated in infected host ...19957755995
potency of endotoxin from bicarbonate dialysate compared with endotoxins from escherichia coli and shigella flexneri.endotoxin is a potent activator of the complement system and other host immunoregulators, including the cytokines, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6. in this study, the potency of an endotoxin from bicarbonate dialysate was compared with endotoxins from two enteric microorganisms, shigella flexneri and escherichia coli. endotoxin concentrations were standardized for the three endotoxins by use of the limulus amebocyte lysate turbidimetric assay. endotoxin potency ...19957756598
[the phagocytic activity of the blood neutrophils in monkeys undergoing multiple irradiation].the study of pathogenic activity of neutrophils under chronic low-dose irradiation (total doses were 0.84-24.99 gy) was carried out. the stage of phase changes was followed by a stable increase in neutrophil phagocytic activity, according to absorbing capacity, at relatively high total doses of irradiation. the data obtained were considered as a defence-compensatory reaction caused by decrease and depression of digestive capacity of phagocytes.19957757188
disulfide oxidoreductase activity of shigella flexneri is required for release of ipa proteins and invasion of epithelial cells.secretion of ipab, ipac, and ipad proteins of shigella flexneri, essential for the invasion of epithelial cells, requires a number of proteins encoded by the spa and mxi loci on the large plasmid. introduction of dsba::tn5 into s.flexneri from escherichia coli k-12 reduced invasiveness, which resulted from a decrease in the capacity to release ipab, ipac, and ipad proteins into the external medium. examination of the surface-presented ipa proteins of the dsba mutant, however, revealed ipa protei ...19957761426
safety and immunogenicity study of the auxotrophic shigella flexneri 2a vaccine sfl1070 with a deleted arod gene in adult swedish volunteers.the live auxotrophic shigella flexneri 2a vaccine strain sfl1070 with a deleted arod gene was given orally to 37 adult swedish volunteers who received three doses within 5 days. each dose comprised 1 x 10(5) (n = 9), 1 x 10(7) (n = 10), 1 x 10(8) (n = 9) or 1 x 10(9) (n = 9) c.f.u. s. flexneri sfl1070. one volunteer vaccinated with 1 x 10(7) and three vaccinated with 1 x 10(8) c.f.u. reported mild gastrointestinal symptoms after the first dose. vaccination with 1 x 10(9) c.f.u. caused abdominal ...19957762285
regulated underexpression and overexpression of the flin protein of escherichia coli and evidence for an interaction between flin and flim in the flagellar motor.the flin protein of escherichia coli is essential for the assembly and function of flagella. here, we report the effects of regulated underexpression and overexpression of flin in a flin null strain. cells that lack the flin protein do not make flagella. when flin is underexpressed, cells produce relatively few flagella and those made are defective, rotating at subnormal, rapidly varying speeds. these results are similar to what was seen previously when the flagellar protein flim was underexpres ...19957768859
shigella enterotoxin 1: an enterotoxin of shigella flexneri 2a active in rabbit small intestine in vivo and in vitro.culture filtrates of shigella flexneri 2a strain m4243 grown in iron-depleted medium, caused significant fluid accumulation in rabbit ileal loops. also, when tested in ussing chambers, a greater rise in potential difference and short circuit current was seen with such filtrates compared with the medium control. analogous filtrates from two m4243 derivatives lacking the 140-md invasiveness plasmid (either m4243avir or bs103) retained 60-65% of the wild-type enterotoxic activity. ultrafiltration a ...19957769126
identification of bacterial genes that contribute to survival and growth in an intracellular environment. 19957773592
[the role of the outer membrane proteins, determined by the shigella flexneri invasiveness plasmid, in inducing cellular immune reactions].fractions of s.flexneri 2a 516 outer membrane proteins determined by plasmid psf140 have been shown to possess immunomodulating activity and to be capable of influencing the intensity of hematopoiesis, manifested by the stimulation of endocolony formation, the increase of the amount of splenic colony-forming units in the marrow, the increase of the pool of proliferating splenic colony-forming units of the marrow and their intensive migration into the blood. outer membrane proteins have been show ...19957778372
[new methodological approaches to the use of the pha reaction in determining anti-shigella antibodies].pronounced correlation between the titers of hemagglutinating antibodies to different types of shigellae and other bacteria in healthy persons and in sick persons of control groups has been established. on the basis of this regularity a new approach to the use of the passive hemagglutination test in shigellosis, taking into account the ratio of antibody titers to different shigella types, has been developed. this essentially increases the sensitivity and specificity of the test, thus making it p ...19957778383
[bactericidal effect of hydrated lime in aqueous solution].this study determined the bactericidal effect of the supernatants of saturated solutions of common lime and of micronized calcium hydroxide (ca(oh)2) (1500 mg/l), which was used as a control, compared with disinfectants made of solutions of 0.33% colloidal silver (0.0016 mg/l), toluene sulfachloramine (41 mg/l) with sodium bicarbonate (9 mg/l), and sodium hypochlorite (5 mg/l). the test involved four strains of vibrio cholerae 01, v. parahaemolyticus, escherichia coli, salmonella typhimurium, sh ...19957779285
contact of shigella with host cells triggers release of ipa invasins and is an essential function of invasiveness.the invasion of colonic epithelial cells by shigella, an early essential step for causing bacillary dysentery, is mediated by the ipab, ipac and ipad proteins. secretion of the ipa proteins from shigella requires functions encoded by the mxi and spa loci. in this study, we show that contact between the bacteria and epithelial cell triggers release of the ipa proteins into the external medium, which results in a rapid decrease in levels of ipa proteins presented on the cell surface. when the bact ...19957781600
a common-source outbreak of shigellosis involving a piped public water supply in northern thai communities.we report an epidemiological investigation of an explosive common-source water-borne shigellosis outbreak traced to a piped public water system in northern thai communities. in august 1991, 242 cases of acute diarrhoeal illness occurred in sam ngao subdistrict, tak province. about 30% of the cases were culture-positive for multiresistant shigella flexneri 2a. the outbreak affected all age groups, with the highest attack rate (9.4%) in children < 5 years old. the first ten cases occurred during 1 ...19957783269
overexpression of the shigella flexneri genes coding for dna topoisomerase iv compensates for loss of dna topoisomerase i: effect on virulence gene expression.introducing the escherichia coli topa20::tn10 allele to shigella flexneri results in osmotic sensitivity, a reduced growth rate, an increase in reporter plasmid supercoiling (all common to the e. coli mutants), an inability to grow on macconkey agar and a loss of virulence gene expression. e. coli mutants harbouring this topa allele often compensate for the loss of dna topoisomerase i by amplifying the genes coding for topoisomerase iv. unlike the e. coli topa mutants, derivatives of s. flexneri ...19957783621
shigella flexneri-hela cell interactions: a putative role for host cell protein kinases.epithelial cell invasion has been shown to be a prerequisite for shigella flexneri virulence. recently, we have documented the induction of transcription factor dna binding activities as a result of s. flexneri challenge of hela cells. in this report, we show that hela cells challenged with s. flexneri display differences in phosphotyrosine-containing proteins. these changes are detected as early as 5 min post-challenge. challenge with a noninvasive ipab mutant strain resulted in the induction o ...19957719286
cytoskeletal rearrangements and the functional role of t-plastin during entry of shigella flexneri into hela cells.shigella flexneri is an enteroinvasive bacterium which causes bacillary dysentery in humans. a major feature of its pathogenic potential is the capacity to invade epithelial cells. shigella entry into epithelial cells is considered a parasite-induced internalization process requiring polymerization of actin. here we describe the cytoskeletal rearrangements during s. flexneri invasion of hela cells. after an initial contact of the bacterium with the cell surface, distinct nucleation zones of heav ...19957721941
a focal adhesion factor directly linking intracellularly motile listeria monocytogenes and listeria ivanovii to the actin-based cytoskeleton of mammalian cells.the surface-bound acta polypeptide of the intracellular bacterial pathogen listeria monocytogenes is the sole listerial factor needed for recruitment of host actin filaments by intracellularly motile bacteria. here we report that following listeria infection the host vasodilator-stimulated phosphoprotein (vasp), a microfilament- and focal adhesion-associated substrate of both the camp- and cgmp-dependent protein kinases, accumulates on the surface of intracytoplasmic bacteria prior to the detect ...19957729410
antibody and cytokine responses in a mouse pulmonary model of shigella flexneri serotype 2a infection.a murine pulmonary model was used to study the mucosal immune response to shigella flexneri serotype 2a infection. inoculation of balb/cj mice with shigellae via the intranasal route resulted in bacterial invasion of bronchial and alveolar epithelia with concomitant development of acute suppurative bronchiolitis and subsequent development of lethal pneumonia. the pathology of pulmonary lesions resembled the colitis that characterizes shigellosis in humans and primates. significant protection aga ...19957729907
[regarding the shigella flexneri 4 strains isolated in recent years].a total of 38 strains of shigella flexneri 4, 14 of which were subserotype 4a but 24 of which were of an undecided subserotype, isolated in recent years, were studied for their biochemical and serological characteristics, and drug susceptibility. among the biochemical characteristics examined, 21 of the 38 strains (55.3%) were mannitol negative biotype and utilized sodium acetate, meanwhile, 17 of the mannitol positive strains did not utilize sodium acetate. the results of serological tests show ...19957745304
persistence of local cytokine production in shigellosis in acute and convalescent stages.shigella infection is accompanied by an intestinal activation of epithelial cells, t cells, and macrophages within the inflamed colonic mucosa. a prospective study was carried out to elucidate the cytokine pattern in shigella infection linked to development of immunity and eradication of bacteria from the local site and also to correlate the cytokine profile with histological severity. an indirect immunohistochemical technique was used to determine the production and localization of various cyto ...19957806368
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