| Project/Area Number |
21K16947
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| Research Category |
Grant-in-Aid for Early-Career Scientists
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| Allocation Type | Multi-year Fund |
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| Review Section |
Basic Section 57020:Oral pathobiological science-related
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| Research Institution | Hiroshima University |
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Principal Investigator |
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,680,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥1,080,000)
Fiscal Year 2023: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
Fiscal Year 2022: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | Klebsiella pneumoniae / virulence factor / hypermucoviscosity / antimicrobial resistance / antimicrobial peptide / bacteriocin / hypervirulent / multidrug resistance / hypermucoviscous / string test / hypervirulence / hypemucoviscosity |
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| Outline of Research at the Start |
K. pneumoniae has emerged as a global life-threatening pathogen due to the multidrug-resistance and hypervirulence phenotype. My study will investigate the genomic population of clinically-isolated hypermucoviscous (HMV) K. pneumoniae isolates in Japan, the correlation between HMV phenotype, virulence genes, and drug resistance genes, and the novel molecular mechanism of HMV phenotype. This study will improve the predictive model for hypervirulent K. pneumoniae and the development of new chemotherapy targeting the novel virulent factors to improve the treatment outcome of this pathogen.
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| Outline of Final Research Achievements |
Hypermucoviscosity (HMV) is a phenotype commonly associated with hypervirulence of Klebsiella pneumoniae (Kp), which is usually regulated by rmpA or rmpA2 genes. Our analysis showed that the low HMV level is usually related to rmpA/rmpA2, while the high HMV level is not. Strains carrying rmpA/rmpA2 are likely to express HMV at 37° C, whereas those negative for these genes are likely to express HMV at room temperature.
Kp also produces several kinds of bacteriocins that have antimicrobial effects against other species. We found that 32.8% of isolates carried at least one bacteriocin type. Microcin E492 was the most prevalent type (14.4%) and had a wide spectrum of activity. Cloacin-like bacteriocin was detected in 7.2% of strains and exhibited inhibitory effect against mainly Klebsiella spp. Other bacteriocins, such as microcin S-like, microcin B17, and klebicin C-like, were detected at lower rates and had limited inhibitory activity.
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| Academic Significance and Societal Importance of the Research Achievements |
Our findings facilitate the discovery of new factors related to HMV and explain different virulence tactics of Kp infection.
Findings about bacteriocins will facilitate studies on competition within microflora and the potential applications of bacteriocins in treating multidrug-resistant bacteria.
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