Key Salivary Proteins Implicated in the Inhibition of Staphylococcus Aureus Biofilms by Chlorogenic Acid

Staphylococcus aureus (S. aureus), a causative agent of infective endocarditis, is found in the oral cavity. Chlorogenic acid (CA) is a polyphenol compound and a secondary metabolite produced by tea, coffee, etc., which are selected as inhibitors of biofilm formation. This study was conducted to clarify how coated human saliva controls the inhibition of S. aureus biofilms by CA. Bacteria were cultivated with various concentrations of CA on nonsalivary components or salivary components-coated 96-well microtiter plates in tryptic soy broth supplemented with 0.25% sucrose and various concentrations of NaCl. The biofilm formation of S. aureus was induced on noncoated plates but inhibited by more than 2.5 mg/mL CA on salivary components-coated plates in 0.125 M or 0.25 M NaCl. The degree of S. aureus biofilm inhibition was affected by coating with different salivary components. In addition, the salivary components, such as α-amylase, upregulated the biofilm formation and were associated with the inhibitory effects of CA on biofilm formation. Exposure to CA through the consumption of coffee and tea may be an inhibitor of biofilm formation by S. aureus via interaction with salivary α-amylase in individuals who consume food and drinks containing high concentrations of salt.