Effects of Berberine chloride hydrate on cariogenic multispecies streptococcal biofilm

Background Dental caries, a bacterial infectious disease related to biofilm, occurs due to an increase in the proportion of cariogenic bacteria over that of commensal bacteria. This study aimed to create an in vitro biofilm model consisting of S. sanguinis, S. gordonii, and S. mutans to study the effects of Berberine chloride hydrate (BH) on the structure and cariogenic features of multispecies biofilms.Materials and methods The biofilm formation and cariogenic characteristics of multispecies streptococci biofilms were observed. The microbial composition of multispecies biofilms was quantified using fluorescent in situ hybridization (FISH). Besides, transcriptome analysis was performed to determine the differential expression levels of genes in each strain in multispecies biofilms with or without BH. The demineralization activity of biofilms treated with BH was analyzed using micro-CT.Results BH had the highest efficacy against S. mutans, exhibiting lower minimum inhibitory concentration (MIC) and minimum biofilm inhibitory concentration (MBIC) values relative to S. sanguinis and S. gordonii. BH inhibited the biofilm formation as well as EPS synthesis in multispecies biofilms, resulting in decreased demineralization on bovine enamel surfaces. In addition, after BH treatment, the abundance of S. sanguinis and S. mutans was reduced, whereas the abundance of S. gordonii increased.Conclusion BH revealed great potential for the management of cariogenic biofilm, indicating its possible application in dental caries therapy.