| Project/Area Number |
24791029
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Infectious disease medicine
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| Research Institution | Juntendo University |
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Principal Investigator |
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| Project Period (FY) |
2012-04-01 – 2015-03-31
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| Project Status |
Completed (Fiscal Year 2014)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2014: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2013: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2012: ¥2,080,000 (Direct Cost: ¥1,600,000、Indirect Cost: ¥480,000)
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| Keywords | MRSA / バンコマイシン耐性 / 黄色ブドウ球菌 / 院内感染症 / slow-VISA / VISA / rpoB / バンコマイシン耐性黄色ブドウ球菌 / ppGpp / 緊縮制御ネットワーク / 緊縮応答 / 薬剤耐性 / 病原性 |
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| Outline of Final Research Achievements |
The Vancomycin(VCM)-intermediate Staphylococcus aureus (VISA) strains generally grow slowly, and form colonies on VCM-containing agar-plates after 48 h of incubation in population analysis. However, we have found a curious group of VISA strains whose colonies appear only after 72 h incubation. We designated them ‘slow-VISA’(sVISA) . As compared to extant VISA strains, sVISA strains had prolonged doubling-times and unstable resistance and growth phenotype. Whole genome sequencing of a representative sVISA strain Mu3-6R-P, which was obtained from hVISA strain Mu3 by selection with 6 mg/L of VCM, revealed a single mutation (R512P), in the rpoB gene encoding beta subunit of RNA polymerase (RNAP), as the responsible mutation for the sVISA phenotype . The sVISA strain had VCM MIC of 16 mg/L. However, after two days of drug-free passage, it generated large colonies, which showed hVISA phenotype carrying mutations (R512L)
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