Preliminary study into the effects of tobacco smoke on Candida albicans

Background: Denture-stomatitis (DS) is the most common form of oral candidosis with increased prevalence in cigarette smokers (Akram et al. 2018). Interestingly, tobacco condensate (TC) increases Candida albicans adhesion, growth, biofilm-formation, virulence gene expression (Semlali et al. 2014)and hyphal production (Awad and Karuppayil 2018). We hypothesised that TC-treated denture acrylic would therefore affect C. albicans within acrylic biofilms. Methods: Acrylic discs (pre-conditioned with TC, artificial saliva (AS) or water) were incubated at 37°C with C. albicans (n=6) for 90 min or 24 h. Adherent Candida were stained with calcofluor white and confocal laser scanning microscopy (CLSM) used to assess levels of adherence, biofilm and hyphal numbers. Expressed virulence genes (n=7) were measured by qPCR. Results: CLSM showed that effects of TC-treatment were strain dependent. Adherence of C. albicans PTR/94 to TC-treated surfaces was significantly (P<0.002) lower than on the untreated control. Biofilm levels of PTR/94 after 24 h were found to be significantly higher on AS-treated acrylic than the TC-treated and untreated control. Five strains had significantly fewer filamentous forms after 90 min on TC-treated surfaces. TC-treatment promoted hyphal levels for strain 705/93 after 24h. Conclusion: TC pre-conditioning altered adherence and biofilm coverage of C. albicans to acrylic surfaces and influenced hyphal development. Work is ongoing to ascertain the significance of these effects on C. albicans pathogenicity. Akram et al. (2018). Journal of Oral Science 60(1):115–120. Awad and Karuppayil (2018). American Journal of Clinical Microbiology and Antimicrobials1 (3):1–6. Semlali et al. (2014). BMC Microbiology . 14:61