Antimicrobial Effect of Phenytoin on Common Microorganisms Contaminating Oral Ulcers: An In-vitro Pilot Study

The antimicrobial effect of phenytoin on ulcers has been addressed in few studies. The aim of this study was to determine the antimicrobial effect of phenytoin on common contaminating microorganisms of oral cavity ulcers in vitro. Three standard microbial species including Staphylococcus aureus, Actinomyces naeslundii, and Candida albicans were prepared. Twenty four-hour cultures of the species was accomplished on BHI Agar medium at 37°C in aerobic situation in an incubator. After 24 hour, 0.5 McFarland concentration were prepared from microorganism colonies. Meadow cultivation of microorganisms was done in plates containing BHI Agar medium. In each plate 4 wells were created for 4 concentrations of phenytoin (0.5, 1, 3, and 5%). Then one drop of each phenytoin solution was poured in the wells in certain concentrations. For each microorganism species, one well containing 0.2% chlorhexidine was prepared as positive control. The plates were placed in incubator and after 24 hour, diameter of non-growth halo around all wells was measured in all plates using a caliper. These steps were repeated three times to ensure the accuracy of process and results. Diameters of non-growth halo around colonies of Staphylococcus aureus, Actinomyces naeslundii, and Candida albicans were 0 millimeter in all four concentrations of phenytoin. Phenytoin was found to have no antimicrobial effect on common contaminating microorganisms of oral cavity ulcers in vitro.