In vitro adhesion of uropathogenic Escherichia coli to human periurethral cells

The in vitro adhesion of three uropathogenic strains of Escherichia coli to epithelial cells from the periurethral area (area surrounding the urethral orifice) of women with and without a history of recurrent urinary tract infections was investigated. All strains showed a specific mannose-resistant hemagglutination restricted to human erythrocytes. Since only a few hundred periurethral cells were used in each test, gentle methods were required. Optimal results were obtained with bacteria grown for 16 h at 37 degrees C in nutrient broth without shaking. The binding of bacteria seemed to be irreversible under the conditions studied, since repeated washings of the epithelial cells after incubation did not decrease the number of adhering bacteria. Chloramphenicol was used to control the number of added bacteria in the incubation system. A difference in the adhesive capacity of periurethral cells of infection-prone and healthy individuals was most evident at concentrations of 2.5 x 10(9) bacteria/ml. Electron microscope studies indicated that pili mediated the adhesion. Adhesion was correlated with the mannose-resistant hemagglutination of human erythrocytes, indicating that the pili were not type 1 pili. Day-to-day variations in the adhesiveness of the bacteria were reduced by selecting well-adhering bacteria with the aid of in vitro passage on periurethral cells or human erythrocytes, and by exclusion of bacteria with low hemagglutination ability.

Identification of a carbohydrate receptor recognized by uropathogenic Escherichia coli

Earlier investigations have shown that pyelonephritic Escherichia coli specifically recognize and bind to carbohydrate structures correlated to the P blood group antigens. These findings are confirmed and extended in this study. Twenty-two of 23 nonselected E. coli strains from children with acute febrile pyelonephritis failed to agglutinate human erythrocytes lacking the antigens within the P blood group system. Only one of 32 faecal isolates exhibited this specific agglutinating property. The new informatin in this paper is that P2k erythrocytes, containing only the Pk antigen, were agglutinated to the same extent by pyelonephritic E. coli strains, giving further support to the proposal that the Pk glycosphingolipid is related to the receptor for pyelonephritic E. coli. In addition, the importance of the oligosaccharide moiety of the Pk glycosphingolipid for the binding of E. coli was further investigated. The synthesized disaccharide alpha-D-Galp-(1-4)-beta-D-Galp-1-O-0-NO2 inhibited the agglutination of human erythrocytes caused by two pyelonephritic E. coli strains at concentrations of less than 1 mM. Hence, the minimal receptor structure recognized by these E. coli strains appears to be the alpha-D-Galp-(1-4)-beta-D-Galp structure. How generally valid this observation may be needs further investigation. The findings may open new possibilities for diagnosis and treatment of urinary tract infection.

Periurethral anaerobic microflora of healthy girls

The periurethral anaerobic and aerobic microfloras were investigated in 18 healthy premenarcheal girls, 5 to 14 years of age, by using a quantitative sampling method. Colonization of the female periurethral area with enterobacteria seems to be an important step in the development of urinary tract infections, and the present study was undertaken as a stage in elucidating factors that might control the establishment of urinary tract pathogens periurethrally. The study showed that obligate anaerobic bacteria constituted 95.0% (standard error, +/- 5.8%) of the total colony-forming units per square centimeter of periurethral area. An average of 7.0 different anaerobic and 2.7 different aerobic strains per specimen was obtained. The flora was dominated by anaerobic gram-positive cocci and gram-positive rods, whereas anaerobic gram-negative rods comprised a minor part. The most commonly encountered anaerobic isolates were peptococci and peptostreptococci, propionibacteria, bifidobacteria, eubacteria, and bacteroides in decreasing order of frequency. The aerobic flora consisted most commonly of nonhemolytic streptococci and diphtheroids. The findings suggest that the periurethral microenvironment is a distinctive ecological niche, separate from the fecal and skin biotas, although it has some characteristics in common with the vaginal flora.

Urinary tract infections treated with single dose of short-acting sulphonamide

In a prospective study 29 patients with urinary tract infections caused by sulphonamide-sensitive organisms were treated with a single oral dose of the short-acting sulphonamide sulphafurazole. Twenty-seven (93%) of the 29 patients--and possibly all 29--were cured of their infections. There was no difference in the recurrence rates after single-dose treatment and treatment for 10 days or more. Six out of eight strains of Escherichia coli causing early recurrences were sensitive to sulphonamides. These results suggest that uncomplicated infections may safely and successfully be treated by a single oral dose of a short-acting sulphonamide.

Bacterial adherence to periurethral epithelial cells in girls prone to urinary-tract infections

Bacterial adherence to epithelial cells from the periurethral region of 48 healthy girls aged over 2 years and of 76 girls with repeated urinary-tract infections was investigated. The infection-prone girls had a significantly higher mean number of adhering bacteria than the healthy controls ( P less than 0.01). This difference was valid irrespective of whether or not the infection-prone girls had urinary-tract infections at the time of investigation. Furthermore, statistically significantly higher numbers of a pyelonephritic strain of Escherichia coli (075:H-:K-non-typable) were found to adhere to washed periurethral cells from infection-prone girls than to cells from healthy controls. These characteristics of the periurethral epithelial cells may facilitate the primary periurethral colonisation which precedes infection of the urinary tract.