Identification of yeast species in the oral cavity of Iranian soldiers by disk diffusion method

Background: The disk diffusion method for identification of yeasts species was performed based on different but distinct susceptibilities of yeasts spp. to chemicals: janus green, ethidium bromide, 2,3,5-triphenyltetrazolium chloride, brilliant green, cycloheximide and rhodamine 6G. Methods: Atotal of 568 Iranian soldiers went under study for isolation and identification of Yeast species from their oral cavity. Asterile swab was used for each individual and specimens were collected from the nasopharynx region, then inoculated to petri dishes containing Sabouraud Dextrose Agar and incubated for 48 hrs at 37 °C. All colonies were counted and stocked in distilled water and stored in a refrigerator for further analysis. The yeasts were identified by the “disk diffusion test” [6,8]. This is a simple, rapid, accurate, and inexpensive technique presented by Sobczak [8]. By this method we identified yeast species within 24-48 hrs. Results: 51.4% of petri dishes were positive for yeast species and 318 strains were identified. Candida albicans, Candida kefyr, Candida tropicalis and Candida guilliermondii were the most common yeast species isolated from the oral cavity of soldiers. Conclusion:We used this method because of its simplicity and other beneficial characteristics for rapid identification of large and numerous isolates and the results were compared with other morphological characters such as chlamydospore and germ tube production. In addition, we used some type strains (Candida parapsilosis: PTCC 5089, Candida tropicalis: PTCC 5028,Saccharomyces cerevisiae: PTCC 5052,Candida lipolytica: PTCC 5063,Candida lipolytica: PTCC 5064), and the results were acceptable.