1999 Fiscal Year Final Research Report Summary
Bacteriological study on pathogenicity and drug resistant of oral streptococci
| Project/Area Number |
09470461
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Surgical dentistry
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| Research Institution | Tsurumi University |
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Principal Investigator |
ISIBASHI Katsumnori Tsurumi University, School of dental medicine, Professor, 歯学部, 教授 (20013980)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKI Fumihiko Tsurumi University, School of dental medicine, Instuctor, 歯学部, 助手 (10318917)
NAGASIMA Hiroyuki Tsurumi University, School of dental medicine, Instructor, 歯学部, 助手 (70257343)
NAKAGAWA Yoiti Tsurumi University, School of dental medicine, Lecture, 歯学部, 講師 (90148057)
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| Project Period (FY) |
1997 – 1999
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| Keywords | Oral steptococci / Pathogenicity / Penicillin binding proteins |
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| Research Abstract |
Oral streptococci are the most predominant oral bacteria, and are related to odontogenic infection and infectious endocarditis. However, the pathogenicity of oral streptococci has not been sufficiently evaluated and little has been known about the mechanism of infection. Recently, there have been reports of acquisition of resistance to β-lactam agents caused by the alteration of penicillin binding proteins(PBPs) in some species of this bacterial genus which were previously sensitive to the agents.
In this study, we evaluated the pathogenicity of β-lactam agent resistant stains of oral streptococci in the treatment of infection. Regarding the evaluation of pathogenicity, we analyzed the pathogenicity of Streptococcus milleri group which was frequently isolated from oral obstructive abscess and the influence of the mixed infection by the S.milleri and anaerobic Fusobacterium nucleatum. An increase size in abscess was observed in the mixed inoculation of S.milleri and F.nucleatum compared
… More
to the single inoculation of the S.milleri group. An increase in the initial proliferation of S.constellatus was observed by mixing the supernatant liquid of cultures for F.nucleatum, with a decrease in phagocytosis of S.constellatus by polymorphonuclear leukocytes and slight inhibition of inflammatory cytokine production. These results suggested that the pathogenicity of the S.milleri group was enhanced by the presence of F.nucleatum in odontogenic infection. Regarding the evaluation of drug resistance, there was the possibility that β-lactam agent resistant streptococci in the indigenous microbiota are present in the normal oral cavity, and a decrease in drug affinity of PBPs in isolated resistant strains was observed. The elucidation of the tendency to acquire resistance and the resistance mechanism of oral streptococci may be important for understanding the pathogencity of oral streptococci, since they have their own latent pathogenicity and a possibility of a potential resistant gene source of Streptococcus pneumoniae. Less
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