I was looking for something that would expand my knowledge of the world around me. Oral biology seemed like a wonderful way to incorporate my fascination with the intricacies of the human body and dentistry. Research in all ways seems like the best way to stimulate learning more about the way that the small details of life can affect society in such an impactful way.

Examining the Probiotic Mechanisms of the Novel Oral Isolate Streptococcus sp. A12

The oral cavity is composed of a variety of microbial species, where certain bacterial taxa are more abundant in health and others in disease. When oral diseases develop, such as dental caries, the biofilm communities are characterized by increased proportions of acidogenic and acid-tolerating species, such as Streptococcus mutans, the number one contributor to human dental caries. In health, the biofilms are associated with higher proportions of commensal and beneficial species, now shown to play active roles in fostering oral health by interfering with the activities of caries pathogens. A novel oral bacterium, designated Streptococcus A12, was isolated from dental plaque of a caries-free individual and was shown to have the ability to effectively antagonize S. mutans. A12 was shown to compete with S. mutans using several gene products, including pcfFEG, encoding a predicted three-component ABC transporter that enhances immunity to bacteriocins. The aim of the project will be to explore the ability of A12 to compete with genomically diverse S. mutans clinical isolates and assess how PcfFEG A12 contribute to interspecies competition. For this, S. mutans isolates containing a spectrum of bacteriocin biosynthetic gene clusters will be selected and competition assays will be performed under a variety of conditions. Simultaneously, the interaction between A12 and other commensal streptococci will be evaluated to better understand how the identified competitive factors in A12 contribute to its overall persistence in complex microbial communities. The results of this study will help us to acquire deeper knowledge on the probiotic mechanisms employed by beneficial commensals and to guide the development of more-effective strategies to control oral diseases.