Profiling of the oral cavity microbiota of young adults and the possible influence of their habits

Abstract

The interest in the human microbiome is increasing in the last years. The oral microbiome includes a broad microbial diversity, related with the environment, physiology, and habits of each individual, impacting their health state. In this study, the prevalence of different bacterial groups in young adults with different daily habits was evaluated. The objective was to understand if the prevalence of major bacterial groups are similar, at the phylum or class level, between individuals or, if they differ if it could be associated with specific behaviours. Since the study aimed to quantify specific taxonomic groups, the technic quantitative polymerase chain reaction was used for that purpose (qPCR). The study focused on saliva samples donated by an anonymous group of 51 young adults, dental medicine students, that filled out a questionnaire about different behaviours and daily habits. The participants, after informed of the objectives and type of study, gave their informed consent to the realization of this study. Based on the extraction of total DNA, the abundance of total bacteria and abundance of the phyla Bacteroidota, Bacillota and Actinomycetota and the classes Gamma- and Betaproteobacteria was assessed. The used primers targeted the 16S rRNA gene, being the sequences specific to different bacterial groups. The abundance of the 16S rRNA gene per volume of sample ranged from 7.3 and 10.0 log ncopies/mL. The phylo Bacteroidota was observed as the most abundant – 6.3 to 9.3 log-units ncopies/mL, in contrast to the Bacillota that presented a lower abundance between 5.5 and 8.1 log-units ncopies/mL. From a set of 19 variables related to personal characteristics and habits that were organized in a binary scale (present/absent or frequently/unusual), it was observable that the sex, consume of antibiotics in the last 12 months, use of chewing gum, onychophagia and biting of pencils or pens were associated with significantly differences in the abundance of some bacterial groups. These differences were most notorious in the cases of Bacillota, Bacteroidota, Actinomycetota and Gammaproteobacteria and sex and antibiotic intake, Betaproteobacteria and CPO and chewing gum use and other bacterial groups and onychophagia and pen biting. Although it is not possible to establish a relation of cause-effect in these associations, it is possible deduce that some specific habits can contribute to shape the oral cavity microbiota.

Date of Award	23 Mar 2023
Original language	English
Awarding Institution	Universidade Católica Portuguesa
Supervisor	Célia Manaia (Supervisor) & Ana Catarina Morouço Ferreira (Co-Supervisor)