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Education
Research
School of Dentistry
The University of Tokushima
　
last update
June 2006

Research Program
  1. Pathogenicity of streptococci
    Objectives
    Streptococcus is a member of oral commensal bacterial flora, and causes dental caries and other diseases. Moreover the bacterium causes diseases in sites other than the oral region. The aim of this study is to isolate and characterize surface structures of streptococci which mimic human molecules.

    Progress Reports
    We have demonstrated an antigen on streptococcal surface immunologically identical to sialyl-LewisX, which has an important role in cancer metastasis and neutrophil rolling.

    Reference
    1. Hiroata, K., Kanitani, H., Nemoto, K., Ono, T., and Miyake, Y.: Cross-reactivity between human sialyl LewisX oligosaccharide and common causative oral bacteria of infective ondocarditis. FEMS Immunol. Med. Microbiol. 12(2), 159-164, 1995.
    2. Hirota, K., Osawa, R., Nemoto, K., Ono, T., and Miyake, Y.: Highly expressed human sialyl LewisX antigen on the cell surface of Streptococcus gallolyticus. Lancet 374, 760, 1996.
    3. Hirota, K., Murakami, K., Nemoto, K., Ono, T., Matsuo, T., Kumon, H., and Miyake, Y.: Fosfomycin Reduces CD15s-Related Antigen Expression of Streptococcus pyogenes. Antimicrob. Agents Chemother. 42(5), 1083-1087, 1998.
    4. Goto, T., Ngamanune, H., Miyazaki, A., Kawamura, Y., Ohnishi, O., Hattori, K., Ohkura, K., Miyamoto, K., Akimoto, S., Ezaki, T., Hirota, K., Miyake, Y., Maeda, T., Kourai, H.:Rapid identification of Streptococcus intermedius by PCR with the ily gene as a species marker gene. J. Med. Microbiol. 51, 178-186, 2002.
    5. Nagamune, H., Ohkura, K., Sukeno, A., Cowan, G., Mitchell, T.J., Ito, W., Ohnishi, O., Hattori, K., Yamato, M., Hirota, K., Miyake, Y., Maeda, T., Kourai, H.: The human-specific action of intermedilysin, a homolog of streptolysin O, is dictated by domain 4 of the protein. Microbiol. Immunol. 48(9), 677-692, 2004.
    6. Sukeno, A., Nagamune, H., Whiley, R.A., Jafar, S.I., Aduse-Opoku, J., Ohkura, K., Maeda, T., Hirota, K., Miyake, Y., Kourai, H.: Intermedilysin is essential for the invasion of hepatoma hepG2 cells by Streptococcus intermedius. Microbiol. Immunol. 49(7), 681-694, 2005


  2. Antibiotic resistance and tolerance of bacteria
    Objectives
    The elevation of antibiotic resistance in streptococci has been reported especially those to penicillins and macrolides. The purpose of this study is to elucidate the resistant mechanism of oral streptococci to penicillins and macrolides and its transmission mechanism between species.

    Progress Reports
    We have found that most of the clinical isolates of Streptococcus mitis/oralis are resistant to macrolides by ribosomal RNA methylation. However, the resistant mechanism of the rest of the strains is still unknown.

    Reference
    1. Ono, T., Shiota, S., Hirota, K., Nemoto, K., Tsuchiya, T., and Miyake., Y.: Susceptibilities of Oral and Nasal Isolates of Streptococcus mitis and Streptococcus oralis to Macrolides and PCR Detection of Resistance Genes. Antimicrob. Agents Chemother. 44(4), 1078-1080, 2000. 　　　　
    2. Tabata, A., Nagamune, H., Maeda, T., Murakami, K., Miyake, Y., Kourai, H.: Correlation between resistance of Pseudomonas aeruginosa to quaternary ammonium compounds and expression of outer membrane protein OprR. Antimicrob. Agents Chemother. 47(7), 2093-2099, 2003. 　　　　
    3. Taniguchi, K., Ono, T., Murakami, K., Viducic, D., Kayma, S., Hirota, K., Nemoto, K., Miyake, Y.: Novel Pseudomonas aeruginosa gene that suppresses tolerance to carbapenems. Antimicrob Agents Chemother. 47(9), 2997-3001, 2003.
    4. Murakami, K., Ono, T., Vicucic, D., Kayama, S., Mori, M., Hirota, K., Nemoto, K., MIyake, H.: Role for rpoS gene of Pseudomonas aeruginosa in antibiotic tolerance. FEMS Microbiol. Letters 242, 161-167, 2005.
    5. Viducic, D., Ono, T., Murakami, K., Susilowati, H., Kayama, S., Hirota, K., Miyake, Y.: Functional analysis of spoT, relA and dksA genes on quinolone tolerance in Pseudomonas aeruginosa under nongrowing condition. Microbiol. Immunol. 50(4), 349-357, 2006.


  3. Bacterial adherence
    Objectives
    The first and essential step of infection is bacterial adherence. It is, hence, of importance to investigate bacterial adherence for elucidation of bacterial pathogenesis.

    Progress Reports
    We have been studying adherence of Staphylococcus aureus to HeLa cells. Purified adhesin from the cell wall fraction of the bacterium found to be a teichoic acid.

    Reference
    1. Matsuura, T., Miyake, Y., Nakashima, S., Komatsuzawa, H., Akagawa, Y., and Suginaka, H.: Isolataion and characterization of teichoic acid-like substance as an adhesin of Staphylococcus aureus to HeLa cells. Microbiol. Immunol. 40(4), 247-254, 1996.
    2. Nemoto, K., Hirota, K., Ono, T., Murakami, K., Murakami, K., Nagao, D., and Miyake, Y., Effect of Varidase (Streptokinase) on Biofilm Formed by Staphylococcus aureus. Chemotherapy 46, 111-115, 2000. 　　　
    3. Nemoto, K., Hirota, K., Ono, T., Murakami, K., Murakami, K., Taniguti, K., Murata, H., Viducic, D., and Miyake, Y., Effect of Varidase (Streptodornase) on Biofilm Formed by Pseudomonas aeruginosa. Chemotherapy 49, 1211-125, 2002.
    4. Hirota, K., Murakami, K., Nemoto, K., Miyake, Y.: Coating of a surface with 2-methacryloyloxyethyl phosphorylcholine (MPC) co-polymer significantly reduces retention of human pathogenic microorganisms. FEMS Microbiol. Letters 248, 37-45, 2005.


  4. Tannin degrading bacteria
    Objectives
    Tannins are widely distributed in a variety of plants and its degrading bacterium was isolated from koala's feces. This study was conducted to survey occurrence of tannin degrading bacteria in various mammals.

    Progress Reports
    Tannin-protein complex degrading bacteria were isolated from 7 out of 54 horses, whereas not from other 14 species of mammals tested. Two strains from human oral cavity, Actinobacillus
    actinomycetemcomitans and Haemophilus segnis, are also positive for tannase.

    Reference
    1. Nemoto, K., Osawa, R., Hirota, K., Ono, T., and Miyake, Y.: An investigation of Gram-negative tannin-protein complex degrading bacteria in fecal flora of various mammals. J. Vet. Med. Sci. 57(5), 921-926, 1995.


  5. Oral care of geriatric patient