The Mechanism of Antibiotic-Resistance in Oral Streptococci
| Project/Area Number |
10671703
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Morphological basic dentistry
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| Research Institution | The University of Tokushima |
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Principal Investigator |
ONO Tsuneko The University of Tokushima, Dentistry, Associate Professor, 歯学部, 助教授 (40035514)
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| Co-Investigator(Kenkyū-buntansha) |
NEMOTO Ken The University of Tokushima, Dentistry, Research Associate, 歯学部, 助手 (10218274)
HIROTA Katsuhiko The University of Tokushima, Dentistry, Research Associate, 歯学部, 助手 (60199130)
MIYAKE Yoichiro The University of Tokushima, Dentistry, Professor, 歯学部, 教授 (80136093)
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| Project Period (FY) |
1998 – 1999
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| Project Status |
Completed (Fiscal Year 1999)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1999: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1998: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Keywords | Streptococcus mitis / Streptococcus oralis / macrolide resistance / erm gene / mefE gene / ketolide / マクロライド耐性 / トランスポゾン / 薬剤排出ポンプ |
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| Research Abstract |
The susceptibility of Streptococcus mitis and Streptococcus oralis isolated from the human oral and nasal cavities to macrolides and benzylpenicillin was determined. Benzylpenicillin yielded a MIC of 【less than or equal】0.002 to 4 μg/ml. Approximately 20% of the isolates were moderately resistant to benzylpenicillin with MICs of 0.12 to 1 μg/ml while one, isolate was highly resistant with an MIC of 2 μg/ml. The MIC range for erythromycin was 0.016 μg/ml to 516 μg/ml. Thirteen isolates were resistant to erythromycin and five, of these were constitutively resistant to azithromycin and clarithromycin, and inducibly resistant to rokitamycin. One isolate was. constitutively resistant to all the, macrolides used in this study. Six strains were highly resistant to erythromycin with an MIC of >512 μg/ml. DNA from all of the. highly erythronrycin-resistant strains and one of the moderately erythromycin-resistant strains gave expected bands as deduced from the corresponding erm gene by PCR ampli
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fication. Also DNA from Staphylococcus epidermidis and S. salivarius isolated from the same patient from which the erm positive streptococcal strains were isolated, produced expected bands as deduced from the erm gene. However, the nucleotide homology of the genes between Streptococcus and Staphylococcus was approximately 50%. This suggests that they are not, of the, same origin. Additionally, DNA from a highly resistant and two moderately resistant strains gave. an mefE PCR product of expected size : as predicted from the corresponding mefE sequence. The mefE-positive. strains possessed erythromycin efflux ability. We examined the antibacterial activity of a new ketolide HMR 3647 to Streptococcus mitis and S. oralis isolates carrying macrolide-resistant genes ermB, mefE and unknown genes. HMR 3647 was highly active to ermB positive, strains compared to erythromycin A and clarithromycin, and more active. than rokitamycin. Although HMR 3647 induced resistance to rokitamycin in ermB positive trains, still active against the resulted strains. Less
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