Author: Nworah Amaka Roseline
Department: Medical Laboratory
Affiliation: Nnamdi Azikiwe University Awka
Candida albicans is an oval yeast that produces a pseudomycelium both in tissue and exudates. It is a normal flora of mucous membrane in the respiratory, gastrointestinal and female genital tracts. The in vitro interaction between clotrimazole and salicylic acid against clinical isolates of Candida albicans and Aspergillus niger was investigated using two different methods: The checkerboard method and the time kill assay. The minimum inhibitory concentration (MIC) of the individual agents was determined using the agar diffusion techniques. The values of the MIC were found to range from 3.125μg/ml to 50μg/ml for clotrimazole and 1.56mg/ml to 25mg/ml for salicylic acid against the clinical isolates of Candida albicans and from 25μg/ml to 50μg/ml for clotrimazole and 12.5mg/ml to 25mg/ml for salicylic acid against Aspergillus niger. The results of the interaction studies were found to be method dependent. There was a good agreement between the checkerboard method and time kill assay both of which indicated a synergistic interaction. Out of the 72 varied combination of the two agents, 61.1% (44 of 72) of the interaction were synergitic ; 29.2% (21 of 72) were indifference and 9.7% (7 of 72) were antagonist for isolates of Candida albicans. For Aspergillus niger, out of the 27 varied combination, 59.3% ( 16 of 27) were synergistic and 40.7% (11 of 27) were indifference while antagonist effect were not observed. The time kill assay also gave a synergistic effect when the two agents were combined that is the killing effects started from 0min down to the 8th h. The outcome of this study is significant in considering combination therapies involving clotrimazole and salicylic acid in the treatment of infections of Candida albicans and Aspergillus niger.