ABSTRACT Objectives: Oral biofilms are complex and contain various microorganisms including bacteria and fungi. Streptococcus gordonii, one of the pioneer oral plaque bacteria, and Candida albicans, the most abundant oral pathogenic fungus, are known to interact with each other. Past studies have shown that S. gordonii binds to hyphae of C. albicans forming a corncob-like structure. However, the exact mechanisms and outcomes of their interactions are not clearly understood. The aim of this study was to demonstrate that C. albicans and S. gordonii confer antimicrobial resistance to one another when grown in co-culture. Methods: C. albicans and S. gordonii were grown in a specially prepared pH adjusted synthetic minimal media [Yeast Nitrogen Base (YNB) + Tryptic Soy Broth Yeast Extract (TSBY)] with and without the antibacterial agent, ampicillin, for 2, 4, 6 and 8 h. The cultures were then filtered to eliminate C. albicans and the resulting filtrate was then plated on TSBY agar and S. gordonii colonies were counted. Similarly, C. albicans and S. gordonii were also grown in co-culture with caspofungin (antifungal agent) for 2, 4, 6 and 8 h. These cultures were plated on YNB agar with ampicillin and the resulting C. albicans colonies were counted. Proteomic analysis of secreted protein resulting from the co-cultures was performed using SDS-PAGE analysis, silver staining, and mass spectrometric analysis. Cell morphology of single and co-cultures were viewed utilizing light microscopy. Results: Growth of S. gordonii in the presence of C. albicans in medium with ampicillin was significantly greater (p<0.05) at 4 and 6 h as compared to growth without C. albicans. In culture medium with caspofungin, however, there was no significant growth of C. albicans even when S. gordonii was present. Proteomic and mass spectrometric analysis revealed differentially secreted proteins in the co-cultures as compared to single cultures. Hyphae formation was detected when C. albicans was grown with S. gordonii but not when grown in single culture. However, there was no evidence of “corncob” formation under these conditions. Conclusion: These data suggest that C. albicans is able to protect S. gordonii from ampicillin-dependent killing and may confer ampicillin resistance. However, S. gordonii does not protect C. albicans from antifungal killing. S. gordonii induces a morphological change in C. albicans from yeast to hyphae. Differentially secreted proteins may be playing a role in the interaction between C. albicans and S. gordonii
|Commitee:||Free, Stephen, Haase, Elaine|
|School:||State University of New York at Buffalo|
|School Location:||United States -- New York|
|Source:||MAI 55/05M(E), Masters Abstracts International|
|Subjects:||Biology, Microbiology, Dentistry|
|Keywords:||Antibiotic, Candida, Gordonii, Proteomic, Resistance, Streptococcus|
Copyright in each Dissertation and Thesis is retained by the author. All Rights Reserved
The supplemental file or files you are about to download were provided to ProQuest by the author as part of a
dissertation or thesis. The supplemental files are provided "AS IS" without warranty. ProQuest is not responsible for the
content, format or impact on the supplemental file(s) on our system. in some cases, the file type may be unknown or
may be a .exe file. We recommend caution as you open such files.
Copyright of the original materials contained in the supplemental file is retained by the author and your access to the
supplemental files is subject to the ProQuest Terms and Conditions of use.
Depending on the size of the file(s) you are downloading, the system may take some time to download them. Please be