Combined DNase and Proteinase Treatment Interferes with Composition and Structural Integrity of Multispecies Oral Biofilms Original paper

What was studied?

The study focuses on the effects of DNase I and proteinase K treatment on multispecies oral biofilms, specifically how these enzymes alter the biofilm’s structure and microbial composition. The researchers tested these enzymes in various concentrations to see how they impacted the biofilm’s integrity, including its exopolysaccharide (EPS) matrix, extracellular DNA (eDNA), and proteins. The goal was to understand how enzymatic treatment could potentially disrupt the biofilm and assist in the delivery of antimicrobial agents to treat biofilm-related oral infections. This study used a six-species biofilm model, including bacteria such as Streptococcus mutans, Fusobacterium nucleatum, Candida albicans, and others, to mimic oral biofilm conditions.

Who was studied?

The study used in vitro biofilms made up of six species: Actinomyces oris, Candida albicans, Fusobacterium nucleatum, Streptococcus oralis, Streptococcus mutans, and Veillonella dispar. These species were chosen due to their relevance in the human oral microbiome and their involvement in dental biofilm formation, which is associated with diseases such as dental caries and periodontitis. The biofilm model was designed to simulate supragingival plaque formation on hydroxyapatite, a material similar to human tooth enamel. The interaction between these species within the biofilm was studied to understand how enzymatic treatments might alter microbial growth and biofilm structure.

Most important findings

The study revealed that DNase I and proteinase K had significant effects on the biofilm structure and composition. DNase I treatment led to a reduction in microbial growth for several species, including Actinomyces oris and Fusobacterium nucleatum, by degrading eDNA, a critical component of the biofilm matrix. On the other hand, proteinase K promoted the growth of Streptococcus mutans and Streptococcus oralis, suggesting that protein degradation within the biofilm could enhance the survival of these species. When both enzymes were combined, there was a noticeable decrease in biofilm density and a shift in microbial composition, with fewer exopolysaccharides and extracellular proteins. This combination also led to a disruption of the biofilm’s structural integrity, reducing the overall stability and making the biofilm more susceptible to antimicrobial treatments.

Key implications

The findings of this study have significant implications for biofilm-related disease treatment in clinical settings. Enzymatic treatments like DNase I and proteinase K could be used in combination with traditional antimicrobial agents to disrupt biofilms and improve drug efficacy. This could be particularly useful for treating oral infections caused by biofilm-forming bacteria, where standard antimicrobial therapies often fail due to the protective nature of the biofilm. Furthermore, understanding how specific enzymes target different biofilm components, such as eDNA and extracellular proteins, can inform the development of tailored therapies that address the complexities of multispecies biofilms. The results also underscore the importance of considering the biofilm composition when selecting treatments, as the presence of certain species like Streptococcus mutans can influence the treatment outcome.