Experimental Study of Ascending <i>Candida albicans</i> Pyelonephritis Focusing on the Hyphal Form and Oxidant Injury

Abstract

To investigate the pathogenicity of the hyphal form of Candida in pyelonephritis a Candida albicans strain, assuming only the yeast form but not the hyphal form when induced by ultraviolet mutagenesis, and a revertant strain from this mutant strain showing bimorphism were compared in a rat experimental model with regard to the incidence of ascending Candida pyelonephritis and the grade of inflammation. To increase the frequency of pyelonephritis unilateral incomplete ureteral stenosis was created. The revertant strain assuming the hyphal form showed a significantly (p < 0.01) higher frequency of pyelonephritis as compared with the mutant strain not assuming this form, and the grade of inflammation was also higher in the revertant strain group. Also, higher renal tissue and serum levels of both lipid peroxide and superoxide dismutase, which are related to marked renal oxidant injury, tended to be correlated with the degree of neutrophil infiltration in the acute phase. These findings suggest that the hyphal form plays an important role in the development of C. albicans pyelonephritis and also that the oxygen radicals from neutrophils appearing at the sites of inflammation play a major part in the further extension of inflammatory lesions.

Candida Infections of the Genitourinary Tract

“…Bacterial UTI has been studied in rodents, dogs, and pigs, but candiduria has been studied predominantly in rats, mice, and rabbits. In these animal experiments, renal candidiasis is achieved mostly by intravenous infection of the yeast (181). This route of infection may not mimic the pathogenesis adequately, because natural infection, especially in the setting of an indwelling catheter, is most often the result of an ascending infection.…”

A murine model for catheter-associated candiduria

“…So far, candiduria has been investigated predominantly in mice, rats and rabbits (Chen et al, 2006;Hurley & Winner, 1963;Khan & Owais, 2006;Navarro et al, 1994;Nishiksawa et al, 1997;Silva et al, 2007;Tarry et al, 1989;Toth & Hughes, 2006). Experiments in larger animals are more costly, cannot be done with large numbers and genetic-knockout strains are limited or do not exist.…”

Inhibitory effect of terbinafine on reactive oxygen species (ROS) generation by Candida albicans

“…Reactive oxygen species (ROS) have received increasing attention as short‐acting compounds involved in inflammation and tissue damage. ROS may react with polyunsaturated fatty acids in cellular membranes, nucleotides, and sulfhydryl bonds in proteins [3], and they have been related to the tissue injury in yeast infections [4].…”