The use of double staining techniques for investigating bacterial attachment to mucopolysaccharide-coated epithelial cells

Applications from bacterial adhesion and biofilm studies in relation to urogenital tissues and biomaterials: a review

The urogenital tract, particularly of the adult female, is the habitat for many species of microorganisms. These populations are in a state of flux, are susceptible to disruption by antibiotics and spermicides, and are exposed to many different biomaterial substrata. Infections of the genital area and bladder are common, and are invariably initiated by microbial adhesion to surfaces. This review examines the actual and potential applications to industry and to patients emerging from the study of bacterial adhesion to surfaces.

Ability of uropathogens to bind to Tamm Horsfall protein-coated renal tubular cells

Epithelial cells were isolated from a healthy human kidney and found to be of normal, renal tubular origin. The cells were maintained in tissue culture and found to secrete Tamm Horsfall protein (THP). Three strains of uropathogenic Escherichia coli, and one each of Proteus mirabilis and Pseudomonas aeruginosa were found to adhere to the THP-coated tubular cells. Extraneous THP bound to all the organisms except P fimbriated E. coli, and caused a reduction in the adhesion of type 1 fimbriated E. coli and P. mirabilis to the renal cells. However, irrespective of reduced adhesion in three of five strains tested, there was adequate evidence to indicate that THP does not competitively exclude all uropathogenic adhesion. On the contrary, its presence on renal cells may act to mediate bacterial colonization.

The human vagina: normal flora considered as an in situ tissue-associated, adherent biofilm

OBJECTIVE

A method that would allow in situ comparison of the degrees of adherence to genital epithelia by the biofilms of the normal flora.

SUBJECTS

Four healthy women.

SETTING

Departments of Biological Sciences, University of Calgary, and of Medicine, University of British Columbia.

METHODS

In situ, scraped specimens were taken from the vagina and ectocervix before and after vigorous vaginal washes, and colony counts of associated bacteria were compared. In vitro, cells from the vulva, vagina and ectocervix were vortexed, centrifuged and sonicated and remaining associated bacteria quantitated by light microscopy.

RESULTS

Anaerobic lactobacilli were notably tissue-adherent as colony counts of postwash specimens were comparable to those of their paired prewash specimens, but crucially were higher than those of their paired wash specimens (p less than 0.05, Wilcoxon signed rank test). However, vaginal and ectocervical coagulase-negative staphylococci and ectocervical Lancefield group B streptococci were loosely tissue-adherent, because counts in postwash specimens were lower than those in prewash or wash specimens (p less than 0.05, Wilcoxon signed rank test). In vitro, only vulvar scrapings and vaginal postwash specimens showed a significant decrease in associated bacteria after shear stressing (p less than 0.05, Wilcoxon signed rank test).

CONCLUSIONS

The normal flora of the female genitalia features both avidly and loosely tissue-adherent bacterial biofilm populations whose adherence can be influenced partly by their location. Our scraping/washing method can contribute to further characterisation of this phenomenon. The superior adherence of anaerobic lactobacilli may reflect a potential in maintaining or restoring normality.

A fluorescent antibody staining technique to detect bacterial adherence to urinary tract epithelial cells

A fluorescent antibody technique has been devised to assess specifically the adherence of Escherichia coli in vitro to uroepithelial cells from healthy women and bacterial adherence in vivo to cells from women with symptomatic urinary tract infection. Similar values can be obtained using methylene blue as the bacterial stain, but this depends on the experience of the observer. The results indicate that E. coli adherence to uroepithelial cells is a factor in the infection process. We suggest that uroepithelial cells from patients with symptoms of a urinary tract infection whose urine has a low bacterial count (less than 10(3) cells/ml) could be examined for the presence of adherent uropathogens, which may be indicative of an infection. Although the fluorescent staining technique possibly would be expensive, the results would be specific and reliable. Other diagnostic and research applications suggest themselves as in studies of bacterial colonization of mucosal tissues or plastic catheters, where conventional light microscopy and radiolabelling methods are not effective.

Bacterial adherence in the human ileal conduit: a morphological and bacteriological study

A retrospective study of 50 patients with urinary diversion was undertaken to determine the incidence of bacteriuria and upper tract infection. Eighty-four per cent of these patients developed bacteriuria caused by a variety of pathogenic organisms and 14 per cent had clinical evidence of pyelonephritis. A phased morphological and bacteriological study was then carried out in a further 17 patients with ileal conduits. Electron microscopy examination of cup biopsy specimens from superficial and deep segments of the conduit showed virtually no bacteria adhering to the columnar cells of the conduit, although Gram positive cocci were seen adhering to the keratinized cells from the muco-cutaneous junction. However, the conduit mucus was heavily colonized, initially with yeasts, then sequentially with microcolonies of Gram-positive and Gram-negative bacteria, up to 16 years after urinary diversion had been performed. Bacteriological examination of conduit and stomal mucus and urine specimens of these 17 patients confirmed the presence of large numbers of uropathogens . Of 23 conduit isolates, 9 possessed hemagglutinins, 18 of 18 attached to uroepithelial cells in vitro and 6 of 6 attached to ureteral transitional cells in vitro, indicating their adhesive and pathogenic capabilities.