Role of tetracycline in pathogenesis of chronic candidiasis of rat tongues.

Forty female Sprague-Dawley rats were randomly divided into two groups. Group 1 animals received tetracycline solution (0.1% during week 1 and 0.01% thereafter) as drinking water, as in previous studies. Group 2 animals received double-distilled demineralized water. Animals in both groups were inoculated orally with an equal number of viable, mucosally pathogenic Candida albicans organisms. After 20 weeks, inspection of the tongues showed gross lesions in 16 of the 20 animals in group 1 and 17 of the 20 in group 2. These lesions were confirmed histologically. No significant difference in the number of lesions was noted between the two groups. However, the lesions in group 1 animals were significantly larger than those in group 2 animals. These results suggest that, given this mucosally pathogenic strain of C. albicans, the establishment of a chronic infection of the rat tongue is apparently not influenced by tetracycline-treated drinking water as administered in this study. This suggests that antibiotic exposure is not an essential factor in the pathogenesis of this lesion. A larger lesion area, however, does appear to be related to the use of tetracycline solution as drinking water.