11th World Congress on Virology and Infectious Diseases
Taylor’s University ,Malaysia
Title: In-vitro antifungal susceptibility test using microbroth dilution method of amphotericin B, fluconazole, voriconazole and ketoconazole against Candida rugosa biofilm
Biography: Priya Madhavan
Statement of the Problem: The virulence of Candida species is due to repertoire of factors, specifically, the ability to form biofilms. Medical devices such as intravenous catheters, prosthetic heart valves and orthopaedic implants provide pathogenic microorganisms with a surface to adhere to form biofilm. Fungi present as biofilms are often resistant to antifungal treatment because these biofilms offer a protective barrier that prohibits the drugs to get to the drug acting sites of the fungi. The objective of this study is to investigate the architecture of the biofilms of Candida rugosa using confocal scanning laser microscopy (CSLM) and antifungal susceptibility patterns of Candida rugosa biofilm at three-time points: 24h, 48h and 72h towards fluconazole, voriconazole, itraconazole and amphotericin B. Methodology & Theoretical Orientation: CSLM was used to visualize Candida rugosa biofilms at 1.5, 6, 12, 18, 24, 48, 72 and 96 hours for two clinically isolated strains of Candida rugosa. For the antifungal susceptibility test, a total of nine clinically isolated strains of Candida rugosa were grown in RPMI-1640 medium at 37ºC at 24, 48 and 72 hours in 96 microtiters well plates. The antifungal susceptibility test was performed using a broth microdilution method according to the M27-A3 guidelines for yeasts. The biochemical quantification of Candida biofilms was performed by the 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT Assay) reduction assay. Findings: From the CLSM images, the mature Candida rugosa biofilms consisted of a dense network of yeasts cells and pseudo-hyphal elements at 24, 48 and 72 hours. Candida rugosa biofilm at all the time points were less susceptible to all the antifungal treatment and exceeded the recommended concentrations. From the antifungal susceptibility test, the biofilms are resistant to fluconazole at >64µg/mL and >16µg/mL for amphotericin B, voriconazole and itraconazole, respectively. Conclusion & Significance: In conclusion, the ability of Candida rugosa to form biofilms may attribute to the resistance towards the antifungals.