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Biomedical subjects

C Svanborg Edén

Publications and source records attributed to C Svanborg Edén.

At least 55 records · Page 3Linked to original sources
PubMed1984

Difference in susceptibility to gram-negative urinary tract infection between C3H/HeJ and C3H/HeN mice.

The difference in susceptibility to urinary tract infection between C3H/HeJ and C3H/HeN mice was tested for with gram-negative strains differing in lipopolysaccharide composition. Recently, impaired clearance of Escherichia coli from the kidney of C3H/HeJ compared to C3H/HeN mice was shown to be correlated with the LPS low responsiveness. In this study, a difference in clearance from the kidneys of C3H/HeJ and C3H/HeN mice was found only with lipopolysaccharide-containing bacteria. Gram-positive bacteria, e.g., Staphylococcus saprophyticus and Streptococcus agalactiae, were recovered in essentially equal numbers from the kidneys of mice of both strains. In contrast, of the lipopolysaccharide-containing strains used, all persisted in higher numbers in the kidneys of C3H/HeJ mice than in the kidneys of C3H/HeN mice. Variations in the O side chain did not eliminate this difference. E. coli Hu734 O75+K5+ and the rfb- mutant O75-K5+ remained in similar numbers in C3H/HeJ mice, although O75-K5+ was eliminated more rapidly in C3H/HeN mice. The core structure did not affect the differential persistence in the two mouse strains. The rfb mutants with R1-R4 cores were eliminated after 24 h from the C3H/HeN mice, but remained in significant numbers in the kidneys of C3H/HeJ mice. Even the Re mutant of Salmonella minnesota persisted in low numbers in C3H/HeJ mice. The relative bacterial recovery from either mouse strain was related to the overall virulence of the infecting bacterial strain, but the difference between C3H/HeJ and C3H/HeN mice was associated with responsiveness to parts of lipopolysaccharide common to the bacterial strains tested.

Animals↗
PubMed1984

Attachment of Streptococcus pneumoniae to human pharyngeal epithelial cells in vitro--mechanism of binding.

To colonize mucosal surfaces and to invade underlying tissues, bacteria need to bind to components of the mucosa. Unattached bacteria are transported away from the surface with the fluid flow. By binding to the nasopharyngeal mucosa, Streptococcus pneumoniae causing otitis media may persist at the site of infection. High binding capacity of the bacterium and increased receptivity of the epithelial cells for attaching bacteria may both contribute to the susceptibility of patients prone to otitis. Thus, epithelial cells from children with frequent episodes of otitis bind attaching bacteria more readily than do cells from age-matched controls. The binding mechanism probably involves bacterial surface proteins and epithelial cell surface glycoconjugate receptors. Evidence is presented that phosphorylcholine, a component of the bacterial surface, as well as epithelial cell receptor analogues, that is, natural or synthetic saccharides analogous to the lactoneoseries of glycolipids, inhibits pneumococcal attachment. Inhibition of bacterial binding in vivo may be a new approach to prophylaxis against otitis media.

Adhesiveness↗
PubMed1984

The immune response of the mammary gland and its significance for the neonate.

The immune response of the mammary gland is dominated by local production of secretory IgA antibodies (SIgA). These milk antibodies, amounting to about 0.5-1 g/day throughout lactation, are directed against food proteins and microorganisms often present in the intestine. This is presumably explained by the enteromammaric link: after antigenic exposure in the Peyer's patches of lymphoid cells they home to various exocrine glands, including the mammary gland. Similarly, lymphoid cells from the bronchial mucosa, may contribute to the antibody-producing cell population in the mammary gland. SIgA antibodies against common foods like cow's milk and soy proteins are regularly found in milk if such proteins are part of the mother's diet. It is possible, but unproven, that milk antibodies can decrease the exposure of the infant's intestinal mucosa to foreign food proteins introduced during continued breast-feeding. Milk SIgA antibodies do not prevent intestinal colonization by microorganisms, against which the milk antibodies are directed. The SIgA antibodies are thought to exert protection primarily by preventing contact between the microorganisms and the mucosal membranes. In this manner, human milk blocks attachment of otitis media-causing strains of pneumococci and H. influenzae to retropharyngeal cells, possibly explaining why breast-feeding may prevent otitis media. Milk antibodies have anti-attachment capacity, but there is also low molecular weight material in the milk with this capacity. It probably consists of analogues to the oligosaccharide receptor for pneumococci on the retropharyngeal cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Contribution of adhesion to bacterial persistence in the mouse urinary tract.

The affinity of uropathogenic Escherichia coli to kidneys and bladders of experimentally infected mice was shown to be determined in part by the adhesive properties of the infecting bacteria. Mice were infected with various pairwise combinations of two homogeneic sets of bacteria: (i) mutants derived from a human pyelonephritis E. coli isolate which were selected to express either or both adhesins specific for globoseries glycolipid receptors or for "mannosides"; and (ii) transformants of a normal fecal isolate which harbored recombinant plasmids encoding the genes for one or the other adhesin or which harbored only the vector plasmid. The relative efficiency of survival of the strains to be compared was evaluated in each animal by plating on selective media of samples of homogenized kidneys and bladders taken 24 h after intravesical inoculation. The presence of adhesins specific for globoseries glycolipid receptors, which mediate the in vitro mannose-resistant attachment to human and mouse uroepithelial cells, enhanced bacterial recovery from both kidneys and bladders of infected animals. The addition to the infecting strain of adhesins binding mannoside residues further improved bacterial recovery from the bladder, but not from the kidney. The mutants and transformants with adhesins binding only mannosides were recovered in higher numbers from the bladder than those expressing adhesins specific for the globoseries glycolipids only. There was apparent selection in vivo decreasing expression of mannoside binding adhesins in the kidneys, but not in the bladders, of animals infected with the mutant expressing both types of adhesins. Regardless of adhesive properties, the mutants of the pyelonephritis isolate were recovered in significantly higher numbers than the fecal isolate with adhesins encoded on recombinant plasmids. We conclude that the adhesive properties in part determine the localization and retention of bacteria in the mouse urinary tract. However, the addition of adhesins to a commensal E. coli strain was not sufficient to confer colonization capacity comparable to that of a pyelonephritis strain.

Adhesins, Escherichia coli↗
PubMed1983

Ascending, unobstructed urinary tract infection in mice caused by pyelonephritogenic Escherichia coli of human origin.

A model for ascending unobstructed urinary tract infection was developed in mice to study the pathogenesis of urinary tract infection induced by Escherichia coli associated with urinary tract infection in humans. Specifically, the model was designed to monitor the initial stages of the infectious process, e.g., bacterial adhesion. Mice were selected since the specificity and intensity of bacterial attachment of pyelonephritogenic E. coli strains to human and mouse uroepithelial cells were similar. Female mice were infected by urethral catheterization and installation of bacteria in the urinary bladder. To maximize clearance of unattached bacteria, no obstructive manipulations were performed. After sacrifice, the persistence of bacteria in kidneys and bladder was determined by viable counts on homogenized tissues. The experimental infection was standardized by using one pyelonephritis (HU734) and one normal fecal (414) E. coli isolate. With both strains all of the bladders became infected, but E. coli 414 was eliminated more rapidly than HU734. The percentage of positive kidney cultures increased with the bacterial inoculum concentration and volume. An inoculum of 0.05 ml containing 10(10) bacteria per ml was selected, giving the highest percentage of positive kidney cultures without detectable bacterial spread to the blood stream. The variation in the percentage of positive kidney cultures possibly depended on the degree of vesicoureteric reflux in the individual animals. Both in the kidneys and in the urinary bladders, strain HU734 yielded higher numbers of bacteria at 24 h and persisted longer than did strain 414. Several E. coli pyelonephritis isolates with properties associated with virulence in the human urinary tract consistently were recovered from mouse kidneys and bladders in higher numbers than E. coli strains of human fecal origin lacking those properties. The role of bacterial adhesion per se is the topic of the accompanying paper.

Adhesiveness↗
PubMed1983

Target cell specificity of wild-type E. coli and mutants and clones with genetically defined adhesins.

The species, individual and tissue specificity of bacterial binding reactions was studied using wild-type E. coli strains from diarrhoea or urinary tract infection, and derivatives with genetically manipulated adhesins. E. coli J96 and GR12 were isolated from the urine of patients with acute pyelonephritis; E. coli strains expressing the CFAI and II antigens from the stools of patients with diarrhoea. E. coli J96, GR12 and CFAI induced mannose-resistant agglutination of human erythrocytes; E. coli J96 and GR12 in addition carried mannose-sensitive adhesins. Mutants of GR12 with either or both of these adhesins were obtained through chemical mutagenesis. Cloning of 6-8 mdal fragments of chromosomal DNA from J96 into E. coli K12 resulted in expression of pili and binding properties in the previously non-piliated and non-binding strain. Bacterial binding was registered to target cells from different human tissues; small intestinal brush borders, uroepithelial and buccal cells and erythrocytes and was compared between species using rabbit intestinal brush borders, mouse bladder cells and guinea pig erythrocytes. Individual variation was illustrated by agglutination of human P1 erythrocytes and those of blood group p lacking the globoseries glycolipid receptors. Specific recognition of globoseries glycolipid receptors was defined as capacity to agglutinate guinea pig erythrocytes after but not before coating with globotetraosylceramide. Binding specific for mannose-containing receptors was diagnosed by mannose-reversible agglutination of guinea pig erythrocytes. The binding pattern of the wild-type strains was related to the site of infection, i.e. the CFAI and II strains bound to small intestinal brush borders and the pyelonephritogenic E. coli to uroepithelial cells, but not vice versa. The mutants and clones retained the binding properties of the parent/donor both in degree and specificity of binding. Strains with adhesins specific for globoseries glycolipids attached to human uroepithelia, mouse uroepithelial and buccal cells. Within the group of strains with mannose-sensitive adhesins heterogeneity was observed. Strains sharing ability to agglutinate guinea pig erythrocytes to a mannose-reversible manner bound or did not bind to human buccal cells, to human uroepithelial cells and agglutinated or did not agglutinate human erythrocytes. The results demonstrate the usefulness of genetic technology in the study of bacterial binding reactions. The role of pili as adhesins is discussed.

Adhesins, Escherichia coli↗
PubMed1983

Molecular mechanisms of adhesion of Streptococcus pneumoniae to human oropharyngeal epithelial cells.

Adherence of bacteria to mucosal surfaces is an early step in colonization and infection. Streptococcus pneumoniae colonizes the nasopharynx and causes localized and systemic disease. The higher adhesion capacity of strains isolated from patients with otitis as compared to strains from sepsis or meningitis patients indicates that binding to the nasopharyngeal mucosa is important in localized but not in invasive infections. The biochemical basis of the pneumococcal binding to epithelial cells has been investigated. Human nasopharyngeal epithelial cells were mixed with pneumococci, and adherence was determined microscopically. Inhibition of adherence with analogues of epithelial cell receptors was tested by preincubation of pneumococci before the addition of the epithelial cells. Competitive inhibition with glycoconjugates, representing receptor structures on the epithelial cell surface, showed receptor function of saccharides containing the disaccharide GlcNAcbeta1 leads to 3Galbeta-.

Disaccharides↗
PubMed1981

Adhesion, hemagglutination, and virulence of Escherichia coli causing urinary tract infections.

The capacity of 453 Escherichia coli strains to agglutinate erythrocytes and yeast cells and to attach to human urinary tract epithelial cells was tested. The strains were isolated from the urine of patients with acute pyelonephritis, acute cystitis, or asymptomatic bacteriuria and from the stools of healthy school children. Three main patterns of hemagglutination were found: (i) mannose-resistant agglutination of human erythrocytes alone or simultaneously with mannose-sensitive agglutination of guinea pig erythrocytes; (ii) only mannose-sensitive agglutination of guinea pig and other erythrocytes; and (iii) no agglutination. Strains with mannose-resistant agglutination of human erythrocytes alone or in combination with mannose-sensitive hemagglutination attached in high numbers to human urinary tract epithelial cells. Bacteria inducing only mannose-sensitive hemagglutination attached in low numbers, and non-agglutinating strains did not bind to the urinary tract epithelial cells. The bacterial surface antigen(s) mediating mannose-resistant hemagglutination of human erythrocytes and attachment to human urinary tract epithelial cells may be one factor selecting for E. coli from among the fecal flora which infect the urinary tract. The highest proportion of strains with this property was found among acute pyelonephritis isolates (77%), and the lowest proportion of strains with this property was found among normal fecal E. coli (16%).

Agglutination↗
PubMed1981

Adhesion of Streptococcus pneumoniae to human pharyngeal epithelial cells in vitro: differences in adhesive capacity among strains isolated from subjects with otitis media, septicemia, or meningitis or from healthy carriers.

A method was developed to study the adhesion of Streptococcus pneumoniae to human pharyngeal epithelial cells. Epithelial cells from healthy persons, pneumococcal strains from patients with otitis media, meningitis, or septicemia, and pneumococcal cells from the nasopharynx of healthy carriers were used. Adhesion was found to be influenced by changes in the bacterial incubation medium and growth phase, the concentration of bacteria and epithelial cells, the epithelial cell donor, the incubation time and temperature, and the pH and osmolarity of the incubation medium. Pretreatment of bacteria with heat, Formalin, or trypsin decreased adhesion. The highest adhesion was obtained when 10(9) bacteria cultivated for 18 h in streptococcus cultivation broth were added to 10(4) pharyngeal cells and incubated at 37 degrees C for 30 min. S. pneumoniae strains from patients with frequent episodes of otitis media and strains from healthy carriers had the highest adhesion values; septicemia and meningitis strains had the lowest. The capsular polysaccharide type did not determine the adhesive capacity of the strains, but otitis strains belonging to the capsular types often associated with otitis media adhered in high numbers. Adhesion may be important for pneumococci colonizing the nasopharynx or inducing otitis media.

Carrier State↗
PubMed1981

Binding specificity of piliated strains of Escherichia coli and Salmonella typhimurium to epithelial cells, saccharomyces cerevisiae cells, and erythrocytes.

The binding to mammalian cells of piliated enteric bacteria and the inhibition of the binding by antibodies to purified pili were studied. The target cells were epithelial cells from human bucca and human and rat urinary tracts, erythrocytes from various species, and Saccharomyces cerevisiae cells. The strains were selected to represent the two main agglutination patterns of enteric bacteria: mannose-resistant agglutination of human and other erythrocytes and mannose-sensitive agglutination of guinea pig and other erythrocytes. Escherichia coli 3669 caused only mannose-resistant agglutination, E. coli 6013 caused only mannose-sensitive agglutination, and E. coli 3048 caused both types of agglutination simultaneously. Salmonella typhimurium SH6749 exhibited only mannose-sensitive hemagglutination and was included to allow comparison of its pili with those of E. coli strains. The range of epithelial cells to which the bacteria adhered was related to their agglutination patterns. All four strains attached to human buccal cells. Only E. coli strains 3669 and 3048, which caused mannose-resistant agglutination, adhered to human urinary tract epithelial cells, and only those strains that caused mannose-sensitive agglutination adhered to rat urinary tract epithelial cells. The binding of S. typhimurium SH6749, but not of the other strains with mannose-sensitive agglutination, was significantly inhibited by d-mannose. Globotetraosylceramide, a glycolipid present in the human urinary tract epithelium, inhibited attachment to human uroepithelial cells of the two strains with mannose-resistant hemagglutination. As tested by the enzyme-linked immunosorbent assay, cross-reactions between type 1 pili of the E. coli strains were strong, but those between S. typhimurium and E. coli mannose-sensitive pili were weak. The two pili that induced mannose-resistant hemagglutination on E. coli did not cross-react. Significant inhibition of adhesion of all four strains was obtained with the homologous anti-pilus antiserum. The binding of bacteria to mammalian cells may thus be mediated by several types of bacterial pili reacting with different receptors on mammalian cells.

Agglutination↗