Caspofungin‐induced in‐vitro post‐antifungal effect and its impact on adhesion related traits of oral Candida dubliniensis and Candida albicans isolates

Arjuna Nishantha Bandara Ellepola, Rachel Chandy, Zia Uddin Khan, Lakshman Perera Samaranayake

Adhesion to buccal epithelial cells (BEC) and denture acrylic surfaces (DAS), germ tube (GT) formation and cell surface hydrophobicity (CSH) are all virulence traits involved in pathogenicity of Candida. Post-antifungal effect (PAFE) also have a bearing on pathogenicity and virulence of Candida. Candida dubliniensis is associated with oral and systemic candidosis, which can be managed with caspofungin. There is no information on caspofungin-induced PAFE and its impact on adhesion traits of C. dubliniensis isolates. Thus, the purpose of this investigation was to determine the in vitro PAFE on 20 C. dubliniensis isolates following brief exposure to caspofungin. Furthermore the impact of caspofungin-induced PAFE on adhesion to BEC and DAS, GT formation and CSH of these isolates were also determined. After establishing the minimum inhibitory concentration (MIC) of caspofungin, C. dubliniensis isolates were exposed to sub-lethal concentrations (×3 MIC) of caspofungin for 1 hour. Thereafter the PAFE, adhesion to BEC and DAS, GT formation and CSH was determined by previously described in-vitro assays. MIC (µg/ml) of C. dubliniensis isolates to caspofungin ranged from 0.004 to 0.19. Caspofungin-induced mean PAFE (hours) on C. dubliniensis isolates was 2.17. Exposure to caspofungin suppressed the ability of C. dubliniensis isolates to adhere to BEC, DAS, GT formation and CSH by a percentage reduction of 69.97%, 71.95%, 90.06% and 32.29% (p <0.001 for all), respectively. Therefore, brief exposure of C. dubliniensis isolates to caspofungin would produce an antifungal effect not only by suppressing its growth but also by altering the adhesion traits of this fungal pathogen.