Acetaldehyde production from ethanol and glucose by non-Candida albicans yeasts in vitro

Background: Major environmental risk factors for upper digestive tract cancers are tobacco smoking, alcohol intake and poor oral hygiene. They all result in increased acetaldehyde (ACH) levels in saliva which has been shown to be carcinogenic. During alcohol challenge the oral microbiota is the main determinant of the local ACH concentration. Many bacteria and Candida albicans have been shown to be capable of ACH production. Moreover, chronic candidal mucositis can be carcinogenic. The ability of non-C. albicans Candida to produce ACH has not been studied. Aim: The aim of this study was to explore the ability of non-C. albicans Candida species to produce ACH in vitro during ethanol and glucose incubation. Methods: A total of 30 non-C. albicans Candida isolates and one C. albicans reference strain were used. The cells were exposed to 11 mM of ethanol and to 100 mM glucose in vitro. ACH was measured by gas chromatography. Results: All Candida isolates produced significant amounts of ACH in ethanol incubation. C. tropicalis isolates were the highest (252.3 μM) and C. krusei isolates were the lowest (54.6 μM) producers of ACH from ethanol. Only C. glabrata produced significant amounts of ACH by fermentation from glucose. Conclusion: Colonization of oral mucosa with a non-C. albicans species such as C. glabrata, capable of producing carcinogenic amounts of ACH from both ethanol and glucose, may contribute to the development of oral cancer. © 2009 Elsevier Ltd. All rights reserved.