A short abstract of the doctoral research

The oral microbiome is a highly diverse microbial community that varies greatly between individuals. Under certain circumstances a healthy microbiome can get disturbed enough so that dysbiosis and the onset of disease occurs. Oral diseases are commonly treated with antimicrobials which are effective at alleviating clinical manifestations. Nonetheless, they can further unbalance the microbiome. The current state-of-the-art is lacking knowledge on the role of the oral microbiome in interindividual differences in response to antimicrobial treatment and focusses heavily on sequencing-based methods. However, it is important to consider the phenotype of the microbial community as it reflects its functionality and can provide clues on the response to treatment. Flow cytometry is an excellent technique for studying phenotypic heterogeneity in microbial populations and forms an interesting platform to explore in oral microbiology research.

This PhD thesis investigates differences in the response to antimicrobial treatment of the oral microbiota and explores possible applications of microbial flow cytometry in oral microbiology. The work shows that shifts in salivary microbiome composition are induced by different antimicrobials and that these changes are donor dependent. Furthermore, the dissertation demonstrates that microbial flow cytometry could be used for both mechanistic research and for differentiating individuals based on their response to antimicrobial treatment. This may open the door for tailored future oral care.