Anaerobiosis and serum promote mycelium formation by Candida albicans in colonies on TSBV agar

Abstract

Following long-term periodontal treatment with tetracycline a superinfection with Candida may arise. The reduced environment and the serum transudate of the periodontal pocket may promote such infection. The present in vitro study was performed to ascertain whether yeast-mycelium transformation in a fresh periodontal isolate was promoted under anaerobic conditions and in the presence of serum. C. albicans, isolated from a patient with tetracycline-treated refractory periodontitis, was cultured anaerobically or aerobically on TSBV or Sabou-raud's dextrose agar at 29°C or 37°C for 72 h, with the pH of the medium being 5.6 or 7.2. TSBV medium was also tested with its horse serum or yeast extract removed. Mycelial growth was recorded visually and by stereo and scanning electron microscopy. Anaerobic culture at 29°C or 37°C on TSBV provided abundant mycelium at both pHs. After aerobic culture the mycelial phase was less pronounced and more abundant at pH 7.2 than at 5.6. TSBV without serum or yeast extract yielded more mycelium after anaerobic than after aerobic culture, although less than when both components were included. Sabouraud's medium provided sparse mycelium after anaerobic culture irrespective of the pH, and no mycelium after aerobic culture.

Key Words:

• Atmosphere
• dimorphism
• nutrients
• periodontology
• pH
• temperature
• yeasts