Abstract
Background: Candida albicans is the most prevalent yeast isolated from the human body and a natural part of the commensal microbiota; however, under the right conditions, C. albicans can cause candidiasis (oral thrush). The oral cavity is colonized by hundreds of bacterial species, and the relationship between these oral bacteria and C. albicans has been a topic of interest in understanding the development of candidiasis. Several studies have attempted to explain the bacteria-fungal relationship in the oral environment, but few have focused on single bacterial species inhibiting growth and morphogenesis of C. albicans. The aim of this study was to identify specific bacterial species, isolated from the healthy human oral cavity, can suppress C. albicans.
Materials and methods: Bacterial and yeast species were isolated and purified from the saliva samples of 12 healthy individuals. PCR was performed by using 16SrDNA and 18S rDNA as templates to identify bacterial and yeast species for all isolates, respectively. Real time qPCR and microscopic examination were carried out to determine the inhibitory effect of S. aureus on C. albicans.
Result: This study demonstrated that numerous bacterial isolates from the oral cavity of healthy humans could inhibit the growth of C. albicans oral isolates, including the model strain CS5314. Among these bacteria, one Staphylococcus aureus strain displayed the strongest inhibitory effect on the growth of yeasts. By qPCR assay, all isolated C. albicans strains were inhibited on the growth by S. aureus in various degrees. Mixed culture experiments also demonstrated suppression of C. albicans pseudo hyphae or hyphae formation by S. aureus but not by other bacterial species tested.
Conclusion: it is well known that C. albicans and S. aureus exist in a cooperative relationship and form substantial polymicrobial biofilm, thus, this is a first report about one clinical isolated S. aureus strain suppressing the growth and pseudohyphae/hyphae formation of C. albicans, indicating the complexity of interspecies interaction in human oral cavity
Citation
Zhou P, Kainthla P, Li X and Qi F. Suppression of Candida albicans Growth and Filamentation by Oral Staphylococcus aureus. SM Journal of Infect Dis. 2017; 2(1): 1005.