Urinary Tract Infections: Normal and Abnormal Host Defense Mechanisms

Microscopic and Ultrastructural Lesions of the Ureter and Renal Pelvis in Sows with Regard to Actinobaculum suis Infection

“…This was due to the layer of mucus on the epithelium and the mucinous granules in the goblet cells. The mucus layer on the transitional epithelium is composed of mucoprotein that prohibits bacterial adherence to the epithelial cells and favours the mechanical washout of bacteria through urination (Parson et al, 1978; Osborne et al, 1979; Jarvinen and Sandholm, 1980). The histology and ultrastructure of the urothelium of the upper urinary tract in healthy sows has been described previously (Woldemeskel et al, 1998).…”

“…In groups 2 and 3 a multifocal desquamation of the superficial cells was detected. The desquamation of some urothelial cells is a normal phenomenon which may be accelerated by abnormal conditions (Osborne et al, 1979). The epithelial exfoliation seen in this study is related to the UTI.…”

“…Alteration of the surface characteristic of the urothelial cells may favour the adhesion of bacteria and establishment of infection. The ability of bacteria to adhere to the surface of cells is an important factor in colonization of the mucosal surface (Osborne et al, 1979). Furthermore, the loss of the superficial mucus layer and of the underlying epithelial cells may expose receptors, such as the microvilli, and favour the adhesion of the micro‐organisms such as A. suis (Parson et al, 1978; Osborne et al, 1979; Walton, 1984; Wendt, 1992; Wendt et al, 1994).…”

“…Furthermore, the involvement of the smooth muscle of the ureter in ureteritis observed in this study may impair peristalsis as observed through dilatation of the ureter by inflammatory exudate. This favoured the urinary reflux into the renal pelvis (Osborne et al, 1979; Risdon, 1994).…”

“…Bacteria sometimes found along the urinary tract are eliminated by the normal flow of urine. The important role played by the urothelial mucosa as a defence against bacterial adhesion and colonization of the urothelium has been described (Parson et al, 1978; Osborne et al, 1979; Jarvinen and Sandholm, 1980). If the defence mechanisms are compromised animals may be predisposed to infection.…”