Tongue coating frequency and its colonization by yeasts in chronic kidney disease patients

The objective of this study was to investigate tongue coating (TC) frequency and its colonization by yeasts in a group of chronic kidney disease (CKD) patients. Clinical examination of the oral mucosa of 33 CKD patients was performed to investigate oral and tongue lesions. TC was diagnosed according to its clinical characteristics. Stimulated saliva and TC samples were collected to verify the salivary flow, and determine yeast frequency, species and counts. TC was found in 18/33 of the patients (54.55 %) and was the most frequent oral lesion found. Of 18 patients with TC, 13 (72.22 %) presented positive cultures for yeasts on the tongue dorsum, and one (5.55 %) in the saliva only. Yeasts were significantly more frequent in the tongue dorsum when compared to the saliva (p = 0.0106). The most frequent yeast species found was C. albicans (55.55 %), while C. parapsilosis comprised 50 % of non-albicans Candida species. This study demonstrated high amounts of yeasts on the cultures from TC samples of CKD patients, strongly suggesting that TC is a clinical representation of a polymicrobial biofilm, which could serve as a gateway for disseminated infection in immunosuppressed patients undergoing frequent hospitalization.