Rasterelektronenmikroskopische Untersuchungen an der Harnblase von Sauen unter besonderer Berücksichtigung einer Eubacterium‐suis‐Infektion

Abstract

Study of Eubacterium-suis Infection in the Bladder of Sow using ElectronmicroscopyScanning electron microscopy was performed on bladder biopsies from 20 sows with cystitis. Results were compared with those of healthy control animals. Biopsy specimens were taken from nine sows infected only with commensal bacteria (E. coli, streptococci, staphylococci) and from 11 sows, where Eubacterium suis (E. su25) was involved in urinary tract infection and had caused a haemorrhagic cystitis. Increased losses of normal superficial cells covered with microplicae could be seen depending on the degree of cystitis. Desquamation of the surface layer exposed smaller cells patterned with short microvilli. These cells were presumed to be immature intermediate cells and goblet cells. Goblet cells were found only in infected organs. The varying surface structure of epithelial cells in relation to receptor quality is important for the bacterial adherence to bladder mucosa.All examined bladders infected with E. suis showed a total loss of superficial cells. Luminal cells covered with multiple short microvilli were accompanied by cells with long pleomorphic processes. Accumulating cell necrosis was indicated by a smooth surface structure. Funnelshaped orifices between the epithelial cells were identified as excretory ducts of mucus-filled cysts, which are formed by the confluence of degenerating goblet cells.E. suis infection of the porcine bladder causes more severe alterations than infections due to other bacteria. However, debilitation of the urothelium due to previous infection is necessary to support infection of the bladder with E. suis.

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

“…These cells are supposed be intermediate cells exposed to the surface after severe desquamation of the superficial cells. Similar findings are described in the urinary bladder of sows infected with unspecific bacteria (E. coli, streptococci) alone or together with A. suis (Wendt et al, 1994). However, some cells which showed a microvilli-like structure on their surfaces also showed a tight junction between two adjacent cells on the luminal side by transmission electron microscopy.…”

“…In severe cases the epithelium of the ureter and renal pelvis in both groups showed acute haemorrhagic, purulent to necrotizing ureteritis and pyelitis/pyelonephritis and in some cases a total loss of the epithelium. Such alterations were not observed in cases of unspecific infections of the bladder and may be typical for A. suis infections (Wendt et al, 1994; Liebhold et al, 1995).…”

“…The epithelial exfoliation seen in this study is related to the UTI. This was reported to be an initial host response to pathogens as experimentally seen in rats infected with Klebsiella pneumoniae (Davis et al, 1977) and in sows with cystitis due to E. coli or streptococci (Wendt et al, 1994). Furthermore, in this study, it was observed that the surface of the ureter and the renal pelvis was covered with cells showing long and short microvilli instead of microplicae as observed in the control group.…”

“…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).…”

“…Clinical findings and patho‐morphological changes in the urinary tract especially in the urinary bladder of sows infected with A. suis have been reported (Kaup et al, 1990; Liebhold, 1991; Wendt, 1992). Wendt et al (1994) described the changes on the bladder mucosa using scanning electron microscopy. Most studies were limited to the urinary bladder with little attention to the upper urinary tract.…”