Altered clinical and histological features of male MM mouse pyelonephritis associated with a change in its microbiology

Abstract

35Summary Radical changes in the clinical, microbiological and histological features of spontaneous pyelonephritis in MM male mice occurred when they were transferred to a new environment after Caesarian derivation. Although the incidence of pyelonephritis remained the same, the survival age was increased. The renal histology indicated a shift to a more chronic form of pyelonephritis with renal amyloidosis as a common feature. At autopsy much more renal scarring was seen, resulting in the 'shrunken' kidney typical of chronic pyelonephritis. Renal lymphocytic accumulations were commonly found in MM mice, but they were also seen frequently in C57BL mice and in germfree stocks of both strains: no association was found between these lesions and pyelonephritis.

A shift from acute to chronic spontaneous pyelonephritis in male MM mice associated with a change in the causal micro-organisms

“…Possible additional genetic factors are suggested by the few MM female cases without accompanying diabetes described in this study and the higher incidence reported elsewhere (Taylor, Fraser & Bruce, 1988). The greatly diminished role of the non-swarming Proteus mirabilis in MM male UTI in EB was puzzling; it is not known how this organism displaced the swarming variety from the gut flora since the swarming type was always present in EA.…”

“…Together with the faecal studies ( Table 6) this suggests that, as in humans, the bacteria found in UTI have a faecal origin. The earlier average age at death of the EA MM pyelonephritics (Tables 1 and 7) was a consequence of the acute nature of Proteus mirabilis UTI (Braude, Siemienski & Shapiro, 1960;Taylor, Fraser & Bruce, 1988). However, the average age at death of animals without renal complications is also much lower in EA.…”

“…There were also striking differences in renal histology between the acute and chronic MM pyelonephritis (Taylor, Fraser & Bruce, 1988).…”

“…The detailed differences in renal histology between EA and EB are described elsewhere (Taylor, Fraser & Bruce, 1988). Although pyelonephritis was seen in one male C57BL, we know that it is rare in C57BLs and our other mouse strains (Taylor & Fraser, 1973).…”

“…In a companion publication it is demonstrated that the changes in the microbiology of the disease were accompanied by alterations in the renal histology (Taylor, Fraser & Bruce, 1988).…”