Antimicrobial Activity of P-113 against Bacterial Flora of the Human Oral Cavity

Periodontitis is a chronic disease associated with dental biofilm formation by bacteria. The primary clinical signs include plaque formation, gingivitis, gingival bleeding, and attachment loss. P-113, a 12-amino acid antimicrobial peptide, is derived from Histatin 5 (Hst5) secreted by the human parotid and submandibular salivary glands and has been reported to reduce plaque formation, gingivitis, and gingival bleeding. This study aimed to investigate the effect of P-113 on periodontal disease-associated bacteria and the relative abundance of bacteria using real-time polymerase chain reaction (real-time PCR) and Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Saliva samples were collected from participants for analyses. Real-time PCR results showed significant changes in the abundance of the periodontal disease-associated bacteria, Fusobacterium nucleatum and Tannerella forsythia, after the use of the P-113 mouthwash. After culturing in an anaerobic environment, MALDI-TOF MS analysis was performed. The results showed that the relative abundance of Streptococcus mitis decreased and that of beneficial Streptococcus salivarius increased after the use of the P-113 mouthwash. These results indicate the potential of P-113 mouthwash as a treatment that can influence the proportion of pathogens and probiotics to establish equilibrium in the salivary environment.