Bacterial colonization of human urethral mucosa. I. Scanning electron microscopy

A scanning electron microscopic investigation of the urethral mucosa of altogether ten men and women subjected to cystourethrectomy because of urothelial cancer of the urinary bladder was performed. The mucosal cells were found to be polygonal and characterized by the presence of microvilli and microridges. No sex difference could be demonstrated. Although a higher number of cells carrying microridges was found in the proximal part of the urethra, no statistical difference in the number of cells with various surface topography was found in different parts of the urethra. The micrographs revealed that the number of urethral cells to which bacteria were attached, was low, also in patients with proven preoperative infection. The bacteria, mainly cocci, seemed to exhibit a preferential adherence to a subpopulation of urethral cover cells, as indicated by the observation that the organisms were not attached randomly. The possibility that different cell surface properties may explain this distribution is considered.