Biomedical subjects

A L Mattos-Guaraldi

Publications and source records attributed to A L Mattos-Guaraldi.

10 recordsLinked to original sources

PubMed2005

Prevalence of IgG diphtheria antitoxin in blood donors in Rio de Janeiro.

The lack of information on the immunity of adults in Brazil against diphtheria prompted us to analyse sera from 234 blood donors aged 18-61 years (30.3% females and 69.7% males). IgG diphtheria antitoxin levels determined by means of an ELISA, validated by toxin neutralization test in Vero cells, showed that 30.7% (95% CI 25.0-37.1) of the population was fully protected (>or=1 IU/ml). The highest percentage of subjects fully protected was in the 31-40 years age group. Most of the subjects with uncertain or no protection (<1 IU/ml) were found in the 18-30 years age group (43.8%, OR 2.18, P=0.01). Antitoxin levels were not influenced by the increase in age. Males were more protected than females (80.5%, OR 0.44, P=0.01). The prevalence of 30% of individuals fully protected against diphtheria in blood donors in Rio de Janeiro supports the fact that immunity to diphtheria among healthy Brazilian adults is inadequate. To avoid diphtheria epidemics in the future the immunity among adults should be raised in the coming years.

Adolescent↗

PubMed2001

Corynebacterium diphtheriae surface proteins as adhesins to human erythrocytes.

Corynebacterium diphtheriae strains express non-fimbrial surface proteins able to recognize and bind to specific host cells receptors. Protein extracts were obtained from bacterial cells by mechanical process and ammonium sulfate precipitation at 25 and 45% (w/v) saturation. SDS-PAGE analysis of the extracts detected two polypeptide bands of 67 and 72 kDa, named 67-72 p. The 67-72 p, rabbit anti-67-72 p IgG antibodies as well as human gastric mucin, N-acetylneuraminic acid and N-acetyl D-glucosamine molecules were able to inhibit bacterial hemagglutination. Hemagglutination assays using 67-72 p-coated latex beads and Western blot analysis of biotin-labeled 67-72 p and erythrocyte receptors demonstrated the binding of 67-72 p to human erythrocyte membranes. Immunolabeled colloidal gold-A protein transmission electron microscopy using anti-67-72 p revealed a diffuse distribution of non-fimbrial 67-72 p on the surface of C. diphtheriae strains of both sucrose-fermenting and non-fermenting biotypes. Non-fimbrial lectin-like surface 67-72 p may play a role as adhesins in bacterial attachment thereby facilitating the early steps in pathogenesis of both toxigenic and non-toxigenic C. diphtheriae.

Acetylglucosamine↗

PubMed2001

Identification of a 43-kDa outer-membrane protein as an adhesin in Aeromonas caviae.

Aeromonas spp. are associated with intestinal and extra-intestinal infections. However, the virulence factors of A. caviae remain, for the most part, poorly known. This study examined the interactions involved in the adherence of A. caviae isolates Ae56, Ae391 and Ae398 to HEp-2 cells. All strains expressed high levels of aggregative adherence. Maximum adhesion occurred with bacteria grown at 22 degrees C, but transmission electron microscopy did not reveal the presence of fimbrial structures on the bacterial cell surface. Outer-membrane proteins (OMPs) extracted from isolate Ae398, grown at 22 degrees C and 37 degrees C, showed similar SDS-PAGE protein profiles. Most proteins were < 60 kDa. A major 43-kDa protein was seen only in the boiled OMP extract. The biotinylated 43-kDa protein bound specifically to HEp-2 cells. Microbeads coated with the 43-kDa protein were also adherent to HEp-2 cells, and anti-43-kDa protein antibody blocked adherence of 43-kDa protein-coated latex beads. These data suggest that the 43-kDa OMP functions as an adhesin in A. caviae.

Adhesins, Bacterial↗

PubMed2000

Cell surface components and adhesion in Corynebacterium diphtheriae.

Main primary approaches and new developments in the study of the molecular basis of the adhesive process of Corynebacterium diphtheriae are reviewed along with a discussion of the potential importance of hemagglutinins, exposed sugar residues, hydrophobins and trans-sialidase enzymes as adhesins of strains of the sucrose fermenting and non-fermenting biotypes.

Bacterial Adhesion↗

PubMed1999

Characterization of surface saccharides in two Corynebacterium diphtheriae strains.

Two Corynebacterium diphtheriae strains were analyzed by assays employing a battery of highly purified fluorescent lectins. From 22 lectins tested only seven with affinity to receptor molecules containing N-acetylglucosamine (D-GlcNAc), N-acetylgalactosamine (D-GalNAc), galactose (D-Gal), mannose-like (D-Man-like) and sialic acid residues showed positive fluorescent labeling. A higher reactivity of Triticum vulgaris (WGA), which binds to sialic acid and/or beta-D-GlcNAc-containing residues, and Bandeiraea simplicifolia II (BS-II), which recognizes alpha and beta-D-GlcNAc units, was shown by the sucrose-fermenting strain. Ricinus communis (RCA-I), which recognizes D-Gal units in addition to both Glycine max (SBA) and Artocarpus integrifolia (Jacaline) agglutinins that bind to D-GalNAc-containing residues, reacted preferentially with the sucrose-negative strain. Canavalia ensiformis (Con A), which recognizes D-Man-like receptors, reacted with both sucrose-fermenting and non-sucrose-fermenting C. diphtheriae biotypes. However, higher interaction was observed with the non-sucrose-fermenting strain. Fluorescence of WGA binding was significantly decreased by neuraminidase treatment suggesting the presence of an exposed sialic acid moiety on C. diphtheriae surfaces. Binding assay using radiolabeled [125I]WGA essentially confirmed the lectin fluorescence studies. N-Acetylneuraminic acid moieties were detected in whole cell hydrolysates as assessed by thin-layer and gas-liquid chromatography. The data indicate differences on the cell surface saccharide ligands between the sucrose-fermenting and the non-sucrose-fermenting C. diphtheriae strains.

Chromatography, Gas↗

PubMed1999

Cell surface hydrophobicity of sucrose fermenting and nonfermenting Corynebacterium diphtheriae strains evaluated by different methods.

Corynebacterium diphtheriae strains expressed variation in hydrophobic characteristics dependent on the method used. Results of single assays are not a reliable representation of C. diphtheriae hydrophobicity. All 12 strains adhered to polystyrene surfaces; three showed spontaneous aggregation (SA) in Trypticase Soy Broth (TSB) medium, and eight exhibited autoagglutination in phosphate-buffered saline (PBS; AA-positive). The salt aggregation test (SAT) values </=0.002 or >/=1.6 represented breakpoints for groups of strains with differing hydrophobicity. C. diphtheriae strains showed affinity towards n-hexadecane. Percentages of adhesion varied from 31% to 63% and were not directly related to morphological n-hexadecane adhesion patterns. Diffuse and localized adhesion patterns were noted predominantly among sucrose-positive and sucrose-negative strains, respectively. Strains of the sucrose-negative biotype expressed a higher degree of hydrophobicity. The choice of the growth medium influenced the hydrophobicity, not the hemagglutinating activity (HA) of C. diphtheriae. Heating bacterial suspensions at 121 degrees C decreased both HA and hydrophobicity of three strains. However, hydrophobins and hemagglutinins were trypsin and detergent resistant. The treatment of microorganisms with Clostridium perfringens neuraminidase increased the hydrophobicity but not the HA titers of strains tested. Hemagglutinins were partially responsible for hydrophobicity. Hydrophilic AA-negative strains adhered strongly to glass but expressed weak HA. Sialylglycoconjugates functioned as hydrophilins on C. diphtheriae surfaces.

Agglutination↗

PubMed1998

Trans-sialidase activity for sialic acid incorporation on Corynebacterium diphtheriae.

A rapid and sensitive assay for neuraminidase using peanut lectin hemagglutination was used to study the prevalence of neuraminidase activity among sucrose-fermenting and non-sucrose-fermenting toxigenic Corynebacterium diphtheriae strains. Neuraminidase activity was found in 15 (100%) isolates regardless of biotype, hemagglutinating activity and site of isolation of bacteria. Besides expressing the neuraminidase activity that hydrolyzes sialic acid from glycoconjugates, C. diphtheriae was also capable of transferring sialic acid residues from a sialyl-lactose donor. A single molecule probably expresses both neuraminidase and trans-sialidase activity. The trans-sialidase activity was documented by observations of the interactions of bacterial cells with wheat germ agglutinin and peanut lectins. C. diphtheriae expressed a trans-sialidase activity located on the cell surface that produced asialoglycoconjugates from a sialyl donor substrate and at the same time generated bacterial sialyl derivatives of beta-Gal acceptors.

Corynebacterium diphtheriae↗

PubMed1991

Relationship of biotype and source to the hemagglutination and adhesive properties of C. diphtheriae.

1. A study was conducted on the hemagglutinating and adhesive properties of sucrose-fermenting and non-sucrose-fermenting Corynebacterium diphtheriae strains. Sheep erythrocytes were agglutinated by 72% of toxigen C. diphtheriae strains and by 87% of nontoxigenic strains, by 67% of the strains isolated from throats and 94% of skin isolates, and by 65% of sucrose-fermenting organisms and 93% of non-sucrose-fermenting strains. 2. Neither presence nor absence of toxin production was correlated with the hemagglutinating property. 3. Different levels of adherence to glass surfaces occurred among C.diphtheriae strains. 4. Strains from skin lesions and of the non-sucrose-fermenting biotype showed strong hemagglutinating activity. 5. In contrast, sucrose-fermenting strains exhibited less hemagglutinating activity, but most of them (71%) were predominantly effective adherers to glass surfaces.

Animals↗

PubMed1986

Agglutination of sheep erythrocytes by Corynebacterium diphtheriae.

The hemagglutinating activity of 26 strains of Corynebacterium diphtheriae isolated from the upper respiratory tract and from skin lesions was determined using both a macro and a micro-technique. Six of the 26 strains tested were unable to agglutinate sheep erythrocytes. Furthermore there was a considerable variation in the hemagglutinating activity of the positive strains.

Bacterial Adhesion↗

PubMedDate not supplied

Corynebacterium diphtheriae threats in cancer patients.

The aim of this study was to determine the bacteriological properties of Corynebacterium diphtheriae strains isolated from bronchiole washing and cancer lesions. Bacteriological characterization included fluorescence/double sugar urease (King/DSU) screening tests, pyrazinamidase (PYZ), CAMP-reactions and radial immunodiffusion toxigenicity assay. Microorganisms produced fluorescence under ultraviolet light and were catalase positive; urea and aesculin hydrolysis negative; fermentation of glucose, maltose and sucrose and no fermentation of mannitol and xylose; PYZ and CAMP reaction negative. The API-Coryne system was used for bacterial preliminary identification at local hospital laboratory and produced numerical profiles 1010325 and 0010325 for sucrose positive C. diphtheriae var. mitis (nitrate positive) and C. diphtheriae var. belfanti (nitrate negative), respectively. The hemagglutination, adherence to glass and polystyrene assays evaluated adhesive characteristics. Strains were toxigenic and able to adhere to glass, polystyrene and human erythrocyte surfaces (titer 4). C. diphtheriae strains isolated from cancer patients expressed adhesive characteristics similar to strains isolated from immunocompetent hosts. Circulation of toxigenic C. diphtheriae continues to present a threat for children and adults including patients with cancer in hospital environment. Laboratories should remain alert to the possibility of isolation of diphtheria bacilli from adults with neoplastic disease.

Adult↗