Rhamnolipids and surfactin inhibit the growth or formation of oral bacterial biofilm

Abstract

Background Bacteria survive in various environments by forming biofilms. Bacterial biofilms often cause significant problems to medical instruments and industrial processes. Techniques to inhibit biofilm formation are essential and have wide applications. In this study, we evaluated the ability of two types of biosurfactants (rhamnolipids and surfactin) to inhibit growth and biofilm formation ability of oral pathogenic bacteria such as Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Streptococcus sanguinis. Results Rhamnolipids inhibited the growth and biofilm formation ability of all examined oral bacteria. Surfactin showed effective inhibition against S. sanguinis ATCC10556, but lower effects toward A. actinomycetemcomitans Y4 and S. mutans UA159. To corroborate these results, biofilms were observed by scanning electron microscopy (SEM) and confocal microscopy. The observations were largely in concordance with the biofilm assay results. We also attempted to determine the step in the biofilm formation process that was inhibited by biosurfactants. The results clearly demonstrated that rhamnolipids inhibit biofilm formation after the initiation process, however, they do not affect attachment or maturation. Conclusions Rhamnolipids inhibit oral bacterial growth and biofilm formation by A. actinomycetemcomitans Y4, and may serve as novel oral drug against localized invasive periodontitis.

Bacteriophage-Derived Depolymerases against Bacterial Biofilm

“…As in the case of any other biological processes, one can identify positive and negative aspects of biofilm formation for human life. For example, bacterial biofilms are crucial for effective functions of microbial fuel cells, for efficient production of various products during fermentation, and for biological stages of wastewater treatment [ 4 ]. However, pathogenic bacteria can form biofilms on surfaces of various materials used in medicine, as well as on surfaces of patients’ tissues [ 5 ].…”

Induction of Systemic Resistance in Maize and Antibiofilm Activity of Surfactin From Bacillus velezensis MS20

“…For example, at a surfactin concentration of 0.625% w/v, growth inhibition of Staphylococcus epidermidis was recorded ( Abdelli et al, 2019 ). Recently, surfactin has been reported to inhibit growth of specific oral pathogens, particularly S. sanguinis ATCC105566 at concentrations of > 1.26 × 10 –3 w/v% ( Yamasaki et al, 2020 ), and removal of biofilms of Legionella pneumophila (6.6 × 10 –3 w/v% of surfactin) ( Loiseau et al, 2015 ). In addition, surfactin is also reported to remove stainless steel and polypropylene surface biofilm of Listeria monocytogenes, Enterobacter sakazakii , and Salmonella enteritidis ( Yamasaki et al, 2020 ).…”

“…Surfactin from Bacillus circulans is an example of a propitious lipopeptide with antimicrobial property ( Das et al, 2008 ). A recently published research article demonstrated antibiofilm property of two biosurfactants (rhamnolipids and surfactin) ( Yamasaki et al, 2020 ).…”

Surface-Active Compounds Produced by Microorganisms: Promising Molecules for the Development of Antimicrobial, Anti-Inflammatory, and Healing Agents

“…For example, RLs produced by P. aeruginosa significantly inhibited the growth of S. mutans UA159 and S. sanguinis ATCC10556. Furthermore, they completely inhibited the growth of Aggregatibacter actinomycetemcomitans Y4 at high concentrations [ 7 ].…”

“…Recently, the production of SACs has received extensive attention because of their diverse applications, such as dissolving water-insoluble compounds, heavy metal binding, contaminant desorption, inhibiting bacterial pathogenesis, adhesion, and cell aggregation [ 4 , 5 , 6 , 7 , 8 ]. In addition, SACs also have several advantages over synthetic surfactants, such as low toxicity, lower critical micelle concentration (CMC), higher biodegradability, and ecological acceptability [ 9 ].…”