Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “SHIGELLA”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed2001

Gene cloning and characterization of alanine racemases from Shigella dysenteriae, Shigella boydii, Shigella flexneri, and Shigella sonnei.

Alanine racemase genes (alr) from Shigella dysenteriae, Shigella boydii, Shigella flexneri, and Shigella sonnei were cloned and expressed in Escherichia coli JM109. All genes encoded a polypeptide of 359 amino acids, and showed more than 99% sequence identities with each other. In particular, the S. dysenteriae alr was identical with the S. flexneri alr. Differences in the amino acid sequences between the four Shigella enzymes were only two residues: Gly138 in S. dysenteriae and S. flexneri (Glu138 in the other) and Ile225 in S. sonnei (Thr225 in the other). The S. boydii enzyme was identical with the E. coli K12 alr enzyme. Each Shigella alr enzyme purified to homogeneity has an apparent molecular mass about 43,000 by SDS-gel electrophoresis, and about 46,000 by gel filtration. However, all enzymes showed an apparent molecular mass about 60,000 by gel filtration in the presence of a substrate, 0.1 M l-alanine. These results suggest that the Shigella alr enzymes having an ordinary monomeric structure interact with other monomer in the presence of the substrate. The enzymes were almost identical in the enzymological properties, and showed lower catalytic activities (about 210 units/mg) than those of homodimeric alanine racemases reported.

Alanine Racemase↗
PubMed2005

Comparison of chromogenic Shigella spp. plating medium with standard media for the recovery of Shigella boydii and Shigella sonnei from tomato surfaces.

Isolation of Shigella spp. from food is difficult because of a lack of appropriate selective media and the presence of low numbers of shigellae relative to competitive microorganisms. Chromogenic Shigella spp. plating medium (CSPM) was evaluated for use with the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) enrichment procedure for isolation of artificially contaminated Shigella boydii UI02 and Shigella sonnei UI05 from tomato surfaces. Tomatoes were inoculated with various concentrations of S. boydii UI02 or S. sonnei UI05 and rinsed using a shake-rub-shake procedure. Tomato rinses were enriched overnight according to the BAM procedure and streaked for isolation on CSPM, Salmonella-Shigella agar (SSA), and MacConkey agar (MAC). To access the isolation of S. boydii UI02 and S. sonnei UI05 without competition from natural tomato microflora, experiments were repeated using rifampin-adapted inocula and enrichments supplemented with 50 microg/ml rifampin. Isolation of S. boydii UI02 and S. sonnei UI05 with or without natural tomato microflora was not significantly different (P > 0.05) on CSPM, MAC, or SSA. Colony color enhancements created by CSPM may ease differentiation of Shigella colonies from those of closely related competitors.

Bacteriological Techniques↗
PubMed2004

In vitro adhesion and invasion inhibition of Shigella dysenteriae, Shigella flexneri and Shigella sonnei clinical strains by human milk proteins.

BACKGROUND: Shigella is the etiological agent of shigellosis, a disease responsible for more than 500,000 deaths of children per year, in developing countries. These pathogens colonize the intestinal colon, invade, spreading to the other enterocytes. Breastfeeding plays a very important role in protecting infants from intestinal infections. Amongst milk compounds, glycosylated proteins prevent the adhesion of many enteropathogens in vitro. The aim of this work was to determine the effect of human milk proteins on the colonization potential of Shigella dysenteriae, S. flexneri and S. sonnei. To fulfill this purpose, pooled milk samples from five donors, were fractionated by gel filtration and affinity chromatography. Using tissue culture, the milk fractions obtained were tested in Shigella adhesion and invasion assays. RESULTS: Our revealed showed that both adhesion and invasion of Shigella species were inhibited by low concentration of secretory immunoglobulin A, lactoferrin and free secretory component. This work also showed that, these proteins bind to superficial and whole-cell Shigella proteins. CONCLUSIONS: Our findings suggest that human milk may act inhibiting adhesion and, consequently, invasion of Shigella, thereafter preventing shigellosis in infants.

Antibodies, Bacterial↗
PubMed1997

Characterization and quantitative analysis of serum IgG class and subclass response to Shigella sonnei and Shigella flexneri 2a lipopolysaccharide following natural Shigella infection.

The IgG subclass response to Shigella sonnei and Shigella flexneri 2a lipopolysaccharide (LPS) was examined in subjects naturally exposed to these organisms. Affinity-purified LPS antibodies obtained using a column of Shigella LPS bound to epoxy-activated Sepharose 6B were used as standards to calibrate the serum antibody response to natural Shigella infection. The geometric mean concentrations of specific IgG in sera from those not exposed to Shigella organisms were 7.9 microg/mL against S. sonnei LPS and 18.6 microg/mL against S. flexneri 2a LPS. After natural exposure to S. sonnei or S. flexneri 2a, the concentrations rose to 30.3 and 127.9 microg/mL, respectively. IgG2 was the major component in the anti-S. flexneri subclass response, while the anti-S. sonnei response was dominated by IgG1. High levels of IgG1 antibodies before exposure to organisms from either Shigella serogroup correlated with a lower risk of developing symptomatic infection.

Adolescent↗
PubMed1977

The pathogenesis of Shigella diarrhea. VI. Toxin and antitoxin in Shigella flexneri and Shigella sonnei infections in humans.

Two strains of Shigella flexneri and one of Shigella sonnei were studied for toxin production in vitro. All of the three strains produced a cell-free cytotoxin that showed marked similarity to that produced by Shigella dysenteriae 1. Each toxin eluted in two distinct peaks on chromatography with Sephadex G-150, was destroyed by heating at 90 C for 30 min, and was neutralized by S. dysenteriae 1 antitoxin. Patients with infections due to S. flexneri and S. sonnei developed antibody that neutralized S. dysenteriae 1 toxin in vitro. In three of seven positive sera studied by sucrose density-gradient ultracentrifugation, antibody activity was associated only with the IgM fraction. The time course of the antibody response resembled that found in infections due to S. dysenteriae 1, in which an IgM antitoxin antibody has also been described. Since three species of Shigella have now been shown to be toxigenic, it is possible that bacterial toxin may play a role, along with bacterial invasion, in the pathogenesis of infections due to S. flexneri and S. sonnei, as well as those due to S. dysenteriae 1.

Antibody Formation↗
PubMed1999

Quantitative analysis of IgG class and subclass and IgA serum response to Shigella sonnei and Shigella flexneri 2a polysaccharides following vaccination with Shigella conjugate vaccines.

It has been recently reported that a conjugate vaccine composed of the O-specific polysaccharide of S. sonnei bound to Pseudomonas aeruginosa recombinant exoprotein A (rEPA) conferred 74% protection against S. sonnei shigellosis. In the present study affinity purified Shigella antibodies were used as standards to quantify and characterize the serum antibody response to vaccination with Shigella sonnei or Shigella flexneri 2a polysaccharide conjugated to rEPA. The geometric mean concentrations of antibodies at the pre-vaccination stage were 3.8 microg/ml for IgG anti-S. sonnei LPS and 11.26 microg/ml for IgG anti-S. flexneri 2a LPS. Vaccination with S. sonnei-rEPA and S. flexneri 2a-rEPA induced the production of specific IgG antibodies to levels of 115.8 microg/ml and 126.5 microg/ml, respectively. The levels of specific antibodies above the pre-vaccination values persisted for at least 2 years. The IgG response to S. flexneri 2a-rEPA conjugate was almost entirely represented by the IgG2 subclass. The concentration of IgG1 anti-S. sonnei LPS was significantly higher than that of IgG2 14 days after vaccination with the homologous conjugate, but decreased to similar levels to those of IgG2 6, 12 and 24 months after immunization. Since the only difference between the S. sonnei and S. flexneri 2a conjugates lies in the different polysaccharides of the two Shigella serogroups (the protein rEPA, is identical in both cases), it follows that the different pattern of IgG subclass response is a result of the different structures of the two O-polysaccharides of S. sonnei and S. flexneri 2a.

Adolescent↗
PubMed1993

Characterisation of Plesiomonas shigelloides strains that share type-specific antigen with Shigella flexneri 6 and common group 1 antigen with Shigella flexneri spp. and Shigella dysenteriae 1.

Three strains of Plesiomonas shigelloides isolated from patients with diarrhoea were agglutinated with Shigella flexneri 6 antiserum in slide and tube tests. All the strains were also agglutinated with a monoclonal antibody to the common group 1 antigen shared between S. flexneri serotypes and S. dysenteriae type 1. Further studies with one strain also showed sharing of antigenicity in an enzyme-linked immunosorbent assay. The results suggest that the strains share type-specific antigen with S. flexneri 6 and the common group 1 antigen with S. flexneri serotypes and S. dysenteriae 1. The sharing of antigens may have implications for cross-protection. One strain adhered to HEp-2 cell monolayers. None of the strains contained high mol. wt plasmids and there was no sequence homology with the invasiveness plasmid of Shigella spp. in DNA probe hybridisation. They were susceptible to the commonly used antibiotics. However, they possessed four other virulence-associated properties of Shigella spp. that included Congo-red binding, hydrophobicity, toxicity to HeLa cells and HEp-2 cell invasiveness (although they gave negative results in the Sereny test for invasiveness). These data suggest that the three unique strains might be considered pathogenic. Studies in animal models and human volunteers would be necessary to establish their pathogenic potential.

Agglutination Tests↗
PubMed1997

Cloning and characterization of the region III flagellar operons of the four Shigella subgroups: genetic defects that cause loss of flagella of Shigella boydii and Shigella sonnei.

To detect genetic defects that might have caused loss of flagella in Shigella boydii and Shigella sonnei, the region III flagellar (fli) operons were cloned from certain strains and analyzed with reference to the restriction maps and genetic maps of Escherichia coli fli operons. S. boydii NCTC9733 (strain C5 in this paper) had the 988-bp internal deletion in the fliF gene that encodes a large substructural protein of the basal body. Two strains (C1 and C8) had deletions of the entire fliF operon, and the remaining three (C3, C4, and C9) differed in the size of the restriction fragments carrying the fliF and fliL operons. Loss of flagella in S. boydii appears to originate in some defect in the fliF operon. S. sonnei IID969 lacked the fliD gene and, in place of it, carried two IS600 elements as inverted repeats. Genes downstream from fliD were not detected in the cloned fragment despite its large size but did appear elsewhere in the chromosome. The fliD gene encodes a cap protein of the flagellar filament, and its deletion results in overexpression of class 3 operons by the increased amount of FliA (sigmaF) caused by the excess export of the anti-sigma factor FlgM. Three other strains also had the fliD deletion, and two of them had another deletion in the fliF-fliG-fliH region. The fliD deletion might be the primary cause of loss of flagella in S. sonnei. The lack of FliF or FliD in each subgroup is discussed in connection with the maintenance of virulence and bacterial growth. We also discuss the process of loss of flagella in relation to transposition of IS elements and alterations of the noncoding region, which were found to be common to at least three subgroups.

Bacterial Proteins↗
PubMed1987

Monoclonal antibodies specific for Shigella flexneri lipopolysaccharides: clones binding to type IV, V, and VI antigens, group 3,4 antigen, and an epitope common to all Shigella flexneri and Shigella dysenteriae type 1 stains.

Monoclonal antibodies reactive with Shigella flexneri O antigens were generated in both mouse and rat systems. Antibody-producing hybridomas were screened in an enzyme-linked immunosorbent assay using chemically defined lipopolysaccharides as antigens, and the epitope specificities were determined with a panel of lipopolysaccharides and synthetic O-antigen-specific glycoconjugates as antigens. To verify the specificity seen in the enzyme-linked immunosorbent assay, the antibodies were used in agglutination against a large number of S. flexneri strains. Monoclonal antibodies with the following specificities were identified: type, antigen IV (reactive with serotype 4a and 4b bacteria); type antigen V (reactive with serotype 5a and 5b bacteria); type antigen VI (reactive with serotype 6 bacteria); group antigen 3,4(reactive with serotype 1a, 2a, 3b, 4a, 5a, and Y bacteria); and group antigen 1 (reactive with an epitope present on all S. flexneri and Shigella dysenteriae type 1 bacteria). Furthermore, a monoclonal antibody defining a new O-antigenic epitope present on some S. flexneri strains of serotypes 4a, X, and Y was characterized (4X). The monoclonal antibodies analyzed in this study define epitopes described by polyclonal antisera (type antigens IV, V, and VI), define a hitherto uncharacterized epitope (group antigen 1), and finally identify new epitopes in what has previously been considered as one epitope (group antigen 3,4 and type antigen IV). These immunochemically characterized monoclonal antibodies may have a powerful potential in studies of the importance of humoral immunity in shigellosis.

Animals↗
PubMed1990

Studies in volunteers to evaluate candidate Shigella vaccines: further experience with a bivalent Salmonella typhi-Shigella sonnei vaccine and protection conferred by previous Shigella sonnei disease.

A bivalent vaccine consisting of Salmonella typhi strain Ty21a containing the 120 MDa plasmid of Shigella sonnei and expressing both S. typhi and S. sonnei lipopolysaccharides (LPS) on its surface was previously shown to protect significantly against S. sonnei disease in experimental challenge studies. However, protective efficacy could not be reconfirmed in volunteers with five subsequent lots of vaccine. One vaccine lot which resembled the initial protective lots of vaccine in biochemical and serological tests, and by electron microscopy, was administered to 16 volunteers who ingested three doses of 10(9) organisms each. Antibody secreting cells (ASC) specific for S. sonnei LPS were detected in the blood of 100% of vaccines, but no protection of these vaccines was demonstrated during a S. sonnei challenge study. To assess the ability of the volunteer model to detect infection-derived immunity, six volunteers who had had clinical shigellosis due to S. sonnei two months earlier were rechallenged with wild-type S. sonnei, together with 12 controls. Prior infection provided 100% protection against febrile illness (p = 0.05) and diarrhea (p = 0.04), thereby validating the volunteer model for assessing Shigella vaccines.

Administration, Oral↗
PubMed1993

Synthesis, characterization, and clinical evaluation of conjugate vaccines composed of the O-specific polysaccharides of Shigella dysenteriae type 1, Shigella flexneri type 2a, and Shigella sonnei (Plesiomonas shigelloides) bound to bacterial toxoids.

The theoretic basis for developing conjugate vaccines, to induce immunoglobulin G (IgG) lipopolysaccharide (LPS) antibodies for the prevention of shigellosis, has been described (J. B. Robbins, C.-Y. Chu, and R. Schneerson, Clin. Infect. Dis. 15:346-361, 1992). The O-specific polysaccharides (O-SPs) of Shigella dysenteriae type 1, S. flexneri type 2a, and S. sonnei were covalently bound to carrier proteins. Alone, the O-SPs were not immunogenic in mice. Conjugates of these O-SPs, injected into young outbred mice subcutaneously as saline solutions containing 2.5 micrograms of saccharide, elicited serum IgG and IgM antibodies with booster responses; adsorption onto alum enhanced their immunogenicity. Injection of 25 micrograms of these conjugates into adult volunteers elicited mild local reactions only. Each conjugate induced a significant rise of the geometric mean serum IgG, IgM, and IgA LPS antibody levels. A second injection 6 weeks later did not elicit booster responses, and adsorption of the conjugates onto alum did not enhance their immunogenicity. Conjugate-induced levels of IgA, but not IgG or IgM, declined to preimmunization levels at day 56. The levels of postimmunization antibodies of the three immunoglobulin classes were similar to or higher than those of recruits in the Israel Defense Force following shigellosis caused by S. flexneri type 2a or S. sonnei. These data provide the basis for evaluating these conjugates to prevent shigellosis.

Adolescent↗
PubMed1964

SURVIVAL OF SHIGELLA IN SEWAGE. II. EFFECT OF GLYCEROL ON SHIGELLA FLEXNERI AND SHIGELLA BACTERIOPHAGE.

Glycerol (30%) inhibited or delayed the adsorption of Shigella bacteriophage on its host organism, S. flexneri II; glycerol also inhibited or delayed the burst of phage, whether or not adsorption was carried out in the presence of glycerol. Studies of the mechanisms of these effects showed that viscosity and osmotic shock probably were not responsible for either phenomenon. The inhibition of adsorption, however, was proportional to the concentration of glycerol, and appeared to be a function of the hydroxyl groups on the glycerol molecule. The inhibition of burst seemed to be related to the osmotic pressure outside the bacterial cells.

Bacteriophages↗
PubMed1995

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 repeating unit as-->4)-alpha-D-GalpA-(1-->3)-alpha-D-GlcpNAc-(1-->3)-alpha-L- Rhap-(1-->2)-alpha-L-Rhap-(1-->2)-alpha-L-Rhap-(1-->.

Antigens, Bacterial↗