This project took an interdisciplinary approach to shed light on how bacteriocins can impact biofilm formation using models of S. mutans caries-associated biofilms.
First, an initial bioinformatic analysis of S. mutans genomes from public databases was performed to get an overview of bacteriocin gene distribution in this species. Next, biofilm-forming and bacteriocin-encoding S. mutans were used to optimise microtiter plate and hydroxyapatite discs-based biofilm models to study bacteriocin-related interactions. Competition experiments with wild-type strains and bacteriocin mutants were performed. These models were used to assess the relevance in mono- and multi-species biofilm formation of bacteriocin structural and putative unpaired immunity genes using mono-species S. mutans and dual-species S. mutans-Streptococcus gordonii and S. mutans- Streptococcus cristatus biofilm set-ups. Finally, to get a deeper overview of which genes were involved in biofilm formation in S. mutans, a transcriptomic analysis of wild type and a bacteriocin deletion mutant challenged with amoxicillin and chlorhexidine was performed. The results show that bacteriocin deletion strains have a competitive disadvantage and exhibit inferior performance in biofilm formation pointing to a potential role of bacteriocin genes in modulating the formation of oral biofilms. Thus, bacteriocin genes could represent potential therapeutic targets for biofilm control. Some experiments of this work are still ongoing.
The project results were presented at several national and international conferences. A review article on the multiple roles of bacteriocins has been published (doi: 10.1007/s00248-024-02357-4. Two research articles are expected to be published from this work. Additionally, the book Novel Approaches in Biopreservation for Food and Clinical Purposes on Food biopreservation was edited as part of external collaborations (ISBN 9781032213552).
As a fundamental research project, the obtained results will mainly appeal to the scientific community in the field of antimicrobials and biofilms. Given the ubiquity of bacteriocins, the implemented bacteriocin-biofilm interactions model can be applied to study other natural or problematic biofilms, in health, the food industry or other industrial processes. Likewise, this project’s results lay the ground to study other bacterial genes that might be involved in biofilm formation with the ultimate goal of better understanding biofilm biology.
