The role of adherence in determining the site of infection by Corynebacterium diphtheriae

Adherence of five serovars of Ornithobacterium rhinotracheale to chicken tracheal epithelial cells

1. Interaction between bacteria and host tissue is important, both for primary adhesion and tissue-specific colonisation, as well as for pathogen invasion for different host tissues. 2. Ornithobacterium rhinotracheale is a bacterium associated with respiratory tract infections in poultry. The mechanisms by which O. rhinotracheale causes infection are not known. To date, at least 18 serovars of this bacterium, with or without the ability to agglutinate erythrocytes of chicken and other species, have been identified. 3. The purpose of this work was to evaluate the ability of five references strains, belonging to serovars A, B, C, D and E, to adhere to a culture of primary chicken tracheal cells. 4. Serovars A and B adhered to less than 20% of tracheal cells with no specific adherence pattern. Serovars C, D and E gave adherence values greater than 70%. Serovars C and E showed a diffuse adherence pattern, while serovar D had an aggregated adherence pattern. 5. The adherence ability and pattern could be associated with different pathogenicity mechanisms in the various serovars but more studies are needed to understand the reasons for these differences.

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.

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.

The study of agglutination of trypsin-treated sheep red cells by Corynebacterium diphtheriae strains

620 Corynebacterium diphtheriae strains from 472 sick and healthy persons were studied for their adhesive activity (AA) in direct agglutination of trypsin-treated sheep erythrocytes. Toxigenic strains had more active AA than non-toxigenic ones which was not dependent on the presence of toxin in the culture. Neither biotype nor serotype of the strains correlated with their AA. Several lysotypes among toxigenic and non-toxigenic strains were more active than others. Toxigenic strains from patients had higher AA than those from carriers. Both toxigenic and non-toxigenic strains isolated from the prolonged carriers possessed the highest AA. It was concluded that AA measured in this way was an important colonization factor for all diphtheria strains and a pathogenicity factor for toxigenic strains.

Adherence and hemagglutination of Corynebacterium group D2

Sixty-one strains of Corynebacterium group D2 were examined for their ability to adhere to human uroepithelial cells and to agglutinate human and guinea-pig erythrocytes. Strains were isolated from samples of two origins: urine of bacteriuric patients and healthy skin of patients without urinary infection. In addition, the isolates were examined by scanning and transmission electron microscopy. Heavy adherence to the uroepithelial cells but weak hemagglutination were noted. No statistical association was demonstrated between the adherence and the origin of the strains (65.2% of urinary isolates and 80% of healthy skin isolates were adherent). On transmission electron microscopy, a close association was observed between adherent bacteria and cells on thin sections and only few strains were piliated with negative staining. These results do not support a role of adherence as a predictor of pathogenicity of Corynebacterium group D2 which seems to act as an opportunistic pathogen in urinary tract infections.

Role of attachment for the virulence of Streptococcus pneumoniae

Adherence of microorganisms to mucosal surfaces is a general phenomenon among microorganisms infecting the human host. Its role for persistence and colonization as well as production of local inflammation is well established. This paper describes the adhesion of Streptococcus pneumoniae to human epithelial cells. Strains from various anatomical sites or diseases are compared for attaching capacity. Isolates from the same host but at different times are also compared. The molecular mechanisms, the so-called adhesin-receptor interactions, are partially described. The pneumococcus recognizes a sugar sequence; GlcNAc beta 1-3Gal; on the surface of the host epithelial cell. Glycoconjugates containing this disaccharide act as receptors for adhering pneumococci. The adhesin in pneumococcal attachment is less well characterized. It is a heat and trypsin sensitive component, most likely a peptide, which forms a bridge between the receptor and an anchoring site in the pneumococcal cell wall. Receptor active saccharides are part of the adhesion-inhibitory activity found in human milk.