Dear Colleagues,

Antimicrobial treatments for bacterial infections are performed as a causative or adjunctive therapy for various diseases. Broadly, it includes antibacterial drugs, antimicrobial photodynamic therapy, and bactericidal peptide. With the decrease of targeted bacteria by antimicrobial treatment, inflammation is suppressed and biological responses such as cytokine secretion or bacterial flora are improved. However, the details related to the mechanism of action of antimicrobial therapy, its effective use, and biological responses have not been fully elucidated. This Special Issue invites articles on antimicrobial therapy and their spread and evolution, including but not limited to the following topics:

• Antimicrobial therapy and immunological response (e.g., immune cells and soluble factors including cytokines and complement)
• Antimicrobial therapy and microbiological response (e.g., composition of the microbial community)
• The evolution and spread of known method of antimicrobial therapy and the emergence of new treatments (e.g., antimicrobial photodynamic therapy and bactericidal peptide)

Dr. Toshiya Morozumi
Dr. Fumihiko Yoshino
Guest Editors

Manuscript Submission Information

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• Antimicrobial therapy
• Dental treatment
• Oral care
• Immunological response
• Antimicrobial photodynamic therapy
• Bacteral flora
• Drug delivery system

Title: Macrolides restrain osteoclastogenesis and inflammation by upregulating homeostatic protein DEL-1
Authors: Hikaru Tamura; Tomoki Maekawa*; Hisanori Domon; Takumi Hiyoshi; Toshihito Isono; Daisuke Yonezawa; Karin Sasagawa; Takeyasu Maeda; Naoki Takahashi; Koichi Tabeta; Yutaka Terao
Affiliation: Niigata University, Japan

Title: Effects of Antimicrobial Photodynamic Therapy on Organic Resolution and Root Surface in vitro
Authors: Yuji Matsushima1; Akihiro Yashima1; Meri Fukaya1; Satoshi Shirakawa1; Tomoko Oshima２; Tomomi Kawai２; Takatoshi Nagano1; Kazuhiro Gomi1
Affiliation: 1 Department of Periodontology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi ku, Yokohama, Japan 230 2 Department of Oral Microbiology, Tsurumi University School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi ku, Yokohama, Japan 230
Abstract: Antimicrobial photodynamic therapy (a-PDT) is garnering attention as a new form of dental treatment. While it is mainly applied as an antibacterial effect, it also reportedly lowers LPS and protease activity. Here, we evaluated differences in antibacterial activity by a-PDT to bacterial types and effects on organic substances such as albumin and LPS. Furthermore, we investigated the effects of a-PDT on root surface. FotoSan630® and toluidine blue were used to perform a-PDT in this experiment. We measured its antimicrobial activity against Porphyromonas gingivalis and Streptococcus mutans, Enterococcus faecalis. Antimicrobial testing revealed strong antimicrobial action against bacteria, with P. gingivalis, E. faecalis, and S. mutans almost undetectable after 50 seconds, 120 seconds and 100 seconds, respectively. In organic resolution tests, Albumin decreased significantly from 1 minute after a-PDT application onward, while lipopolysaccharides (LPS) had decreased significantly at 5 minutes after application. The root surfaces applied a-PDT was confirmed to be cleaner than in the controls without suffering any damage. On this study, a-PDT exhibits antimicrobial activity against various types of bacteria, sensitivity differs depending on the species of bacteria. We also found that a-PDT resolves protein and LPS, enabling the formation of a healthy root surface without any damage.

Title: Control effect of oral bacterial flora by natural antibacterial ingredient catechin
Authors: Muneaki Tamura; Noriaki Kamio; Kuniyasu Ochiai; Kenichi Imai
Affiliation: Department of Microbiology, Division of Immunology and Pathobiology, Dental Research Center, Nihon University School of Dentistry