Prevalence of non-albicans Candida in saliva of an elderly population

Objectives: Oral yeast infections can be highly detrimental for medically compromised and elderly patients. Candida albicans is a common colonizer of the oropharyngeal tract and its prevalence in the saliva of elderly in Finland has been reported to be up to 75% (Närhi et al. J Dent Res 1993). However, data are sparse regarding the prevalence of non-albicans Candida. Therefore, we set out to investigate in a group of elderly subjects the prevalence of oral Candida, including the non-albicans strains. We expected, nevertheless, to detect mostly C. albicans. Methods: Paraffin-wax stimulated saliva samples from originally 276 elderly living in old peoplexs homes in Helsinki were taken and cultivated on Sabaroud agar followed by sub-culturing onto CHROMA-Agar Candida® (Becton Dickenson, NJ) for identification of C. albicans, C. krusei, C. glabrata, and C. tropicalis. Resistance of the identified strains to antifungal agents was assessed by using the Neo-Sensitabs® method of Rosco Diagnostica AS. Final results were received from 147 subjects, 70-100 years old. Results: No yeast growth was observed in 12 specimens (8%). Of the remaining specimens, C. albicans was detected in 92%, C. glabrata in 1.5%, and C. tropicalis in 0.7%. In 6% the strain identification was not successful. Fluconazole resistance was observed in 4.5%, itraconazole resistance, respectively, in 3.3%, mostly in the non-albicans yeasts. Conclusion: As expected, C. albicans was the most prevalent strain in saliva samples of the elderly. However, the non-albicans strains, albeit more rare, often showed resistance towards commonly used antifungal agents. This aspect must be taken into account in clinical decision making when planning treatment of oral yeast infection among the elderly.