Interaction Between Oral Streptococci and Candida Albicans

Candida albicans is an opportunistic oral pathogen and has the ability to cause disease in immuno-compromised patients. Oral streptococci are primary colonizers and major constituents of oral cavity. Interaction between C. albicans and oral streptococci is important for maintaining balanced, healthy oral environments. Objective: of this study is to determine the interactions between C. albicans and oral streptococci. Methods: Each Oral streptococci (S. mitis BV2,S. sanguis SK36, S.parasanguis FW213, and S.oralis J22) were co-cultured with either yeast C. albicans or isogenic filamentous C. albicans in the THB media, their interactions were examined using a phase contrast microscope and images of interactions were captured using a digital camera. Results: Oral streptococci promoted proliferation of both forms of C. albicans in a time dependent manner. S. mitis noticeably aggregated into bundles when either yeast or filamentous forms of C. albicans were present. These bundles seemingly increased in size with time. Aggregates of S. mitis did not form when tested in culture supernatants from C. albicans. However, growth of S. mitis was inhibited when S. mitis was inoculated in C. albicans culture supernatants, such inhibition was reversed by introducing glucose into the culture supernatants. These results suggest a direct communication between S. mitis and C. albicans is needed for the formation S. mitis bundles. Conclusion: Oral streptococci interact with C. albicans. Oral streptococci promote proliferation of C. albicans whereas C. albicans induces S. mitis aggregation by an unknown direction communication mechanism between C. albicans and S. mitis. This work was supported by UAB NIH training grant for Short-Term Training in Health Professional Schools. The grant number is T35 HL07473.