Details of a Researcher

Hirai Itaru

写真a

Title	Professor
Researcher Number(JSPS Kakenhi)	00359994

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Current Affiliation Organization 【 display / non-display 】

Duty University of the Ryukyus Faculty of Medicine Health Sciences Professor
Concurrently University of the Ryukyus Graduate School of Health Sciences Division of Health Sciences Professor

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External Career 【 display / non-display 】

2013.04

　

　

University of the Ryukyus, Faculty of Medicine, School of Health Sciences, Professor

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Affiliated academic organizations 【 display / non-display 】

　

　

　

JAPANESE SOCIETY FOR BACTERIOLOGY
　

　

　

THE JAPANESE ASSOCIATION FOR INFECTIOUS DISEASES
　

　

　

American Society for microbiology

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Research Interests 【 display / non-display 】

Molecular Cellular Biology
Biochemistry
Molecular Microbiology

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Research Areas 【 display / non-display 】

Life Science / Bacteriology
Life Science / Bacteriology

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Published Papers 【 display / non-display 】

Species identification and genotyping of Citrobacter spp. using genes with high nucleotide diversity

Yagi, N; Nashiro, R; Hirai, I

MICROBIOLOGY SPECTRUM ( Microbiology Spectrum ) 14 ( 6 ) e0364625 - 13 2026.06 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)
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Application of newly developed PCR detection and sequencing methods for the lafA gene to Aeromonas isolates.

Miyagi K, Shimoji N, Hirai I

Journal of microbiological methods ( Journal of Microbiological Methods ) 241 107375 - 107375 2026.02 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)
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A Monitoring Method to Evaluate the Accumulation of Antimicrobial-Resistance Genes in Gram-Negative Bacteria Distributed in Environmental Water

Yagi, N; Miyazato, S; Anh, NQ; Huong, BTM; Hirai, I

ENVIRONMENTAL MICROBIOLOGY REPORTS ( Environmental Microbiology Reports ) 17 ( 6 ) e70265 2025.12 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)
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Differences in flaA gene sequences, swimming motility, and biofilm forming ability between clinical and environmental isolates of Aeromonas species

Miyagi, K; Shimoji, N; Oshiro, H; Hirai, I

ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH ( Environmental Science and Pollution Research ) 30 ( 5 ) 11740 - 11754 2023.01 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)

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The flagellin A gene (flaA) sequences, swimming motility, and biofilm forming ability were investigated in order to reveal the genetic and functional differences of flagella between clinical and environmental isolates of Aeromonas species. Twenty-eight clinical and 48 environmental strains of Aeromonas species isolated in Okinawa Prefecture of Japan were used in this study. The full-length flaA genes of these strains were sequenced and aligned, and a phylogenetic tree was constructed. In addition, swimming motility and biofilm forming ability were evaluated by conventional methods. Aeromonas veronii biovar sobria and A. hydrophila clearly divided into clinical and environmental strain clusters in the flaA phylogenetic classification, and the six and 13 specific amino acids respectively, of FlaA of both species were different in clinical and environmental strains. Furthermore, the flaA size of the clinical strain of A. veronii bv. sobria was mainly 909, 924, and 939 bp, and the size of A. hydrophila was 909 bp. The swimming motility of clinical isolates of both species was lower than the environmental isolates; however, the biofilm forming ability of the clinical isolates was high. Thus, the clinical isolates of A. veronii bv. sobria and A. hydrophila had different genetic and functional characteristics of flagellin than the environmental isolates. The characteristics of flagellin could serve as indicators to distinguish between clinical and environmental isolates of the both species. It may contribute to diagnosis of these diseases and the monitoring of clinical strain invasion into the natural environment.
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Analysis of the upstream genetic structures of the ISEcp1-bla CTX-M transposition units in Escherichia coli isolates carrying bla CTX-M obtained from the Indonesian and Vietnamese communities.

Widyatama FS, Yagi N, Sarassari R, Shirakawa T, Le DT, Bui MHT, Kuntaman K, Hirai I

Microbiology and immunology 2021.09 [ Peer Review Accepted ]

Type of publication: Research paper (scientific journal)
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