Hirai Itaru




Researcher Number(JSPS Kakenhi)


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  

External Career 【 display / non-display

  • 2013.04

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

Affiliated academic organizations 【 display / non-display






    American Society for microbiology 

Research Interests 【 display / non-display

  • Molecular Cellular Biology

  • Biochemistry

  • Molecular Microbiology

Research Areas 【 display / non-display

  • Life Science / Bacteriology

  • Life Science / Bacteriology

Published Papers 【 display / non-display

  • Analysis of the upstream genetic structures of the ISEcp1-bla <sub>CTX-M</sub> transposition units in Escherichia coli isolates carrying bla <sub>CTX-M</sub> 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)

  • A high-throughput sequencing determination method for upstream genetic structure (UGS) of ISEcp1-bla<sub>CTX-M</sub> transposition unit and application of the UGS to classification of bacterial isolates possessing bla<sub>CTX-M</sub>.

    Yagi N, Hamamoto K, Thi Bui KN, Ueda S, Tawata S, Le DT, Thi Bui MH, Hirai I

    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy ( Journal of Infection and Chemotherapy )  27 ( 9 ) 1288 - 1294   2021.09 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    INTRODUCTION: Because blaCTX-M is responsible for resistance of bacteria to the third generation cephalosporins, location of blaCTX-M could be a good indicator for classifying bacterial isolates harboring blaCTX-M in molecular epidemiology. However, determination of blaCTX-M location has been difficult when multiple copies of ISEcp1 were found on bacterial genome. We aimed to establish a high-throughput analytical method for upstream genetic structures (UGS) of ISEcp1 to facilitate determination of blaCTX-M location. METHODS: Extracted DNA samples obtained from 168 Escherichia coli isolates possessing blaCTX-M were digested by restriction enzyme, HaeIII, and the digested DNA fragments were ligated with homemade barcode adaptors. Then, DNA fragments containing UGS of ISEcp1 were amplified and subjected to the Nanopore sequencer. RESULTS: Nucleotide sequences and locations of 168 UGSs obtained from the examined E. coli isolates were determined. Among the 168 determined UGSs, 150 (89.3%) UGS were confirmed on plasmid and classified into eight types. Interestingly, coding sequence of ISEcp1 transposase gene in seven of the eight types were disrupted by IS26 insertion. The remaining 18 (10.7%) UGSs were observed in identical chromosomal region. The obtained nucleotide sequences the locations of UGSs were confirmed by conventional capillary sequencer and Southern blotting, respectively, and any discrepant result was not observed with these confirmation procedures. CONCLUSIONS: Our results indicated that the established method was efficient for simultaneously determining at least 100 different UGS, and suggested that the determined UGSs of ISEcp1-blaCTX-M transposition unit was useful for classification of bacterial isolates harboring blaCTX-M.

  • Occurrence of Carriage of Multidrug Resistant Enterobacteriaceae among Pregnant Women in the Primary Health Center and Hospital Setting in Surabaya, Indonesia.

    Oktaviani Sulikah SR, Hasanah M, Setyarini W, Parathon H, Kitagawa K, Nakanishi N, Nomoto R, Osawa K, Kinoshita S, Hirai I, Shirakawa T, Kuntaman K

    Microbial drug resistance (Larchmont, N.Y.)     2021.08 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    Objectives: The incidence of healthy individuals carrying multidrug resistant Enterobacteriaceae, including extended-spectrum β-lactamase producing Enterobacteriaceae (ESBL-E), especially extended-spectrum β-lactamase producing Escherichia coli (ESBL-EC) and extended-spectrum β-lactamase producing Klebsiella pneumoniae (ESBL-KP), is increasing worldwide. Although ESBL-E causes early or late onset of neonatal sepsis, the prevalence of ESBL-E carriage among pregnant women in Indonesia is not clear. In the present study, we compared the occurrence of carriage of ESBL-E among pregnant women in a primary health center (PHC) versus two hospitals. Materials and Methods: We collected rectal swab samples from 200 pregnant women who visited a PHC or were admitted to two hospitals in Surabaya, Indonesia from July to October 2018. The ESBL-E strains were isolated from the samples and phenotypically and genotypically analyzed. Results: ESBL-E strains were isolated from 25 (24.8%) pregnant women who visited the PHC and 49 (49.5%) pregnant women who were admitted to the hospitals. The rate of ESBL-E carriage of pregnant women in the hospitals was significantly higher than that in the PHC. Among the 74 isolated ESBL-E strains, ESBL-EC was most frequently isolated (62 strains), followed by ESBL-KP (12 strains). In addition, blaCTX-M-15 was the most frequent ESBL gene type of the isolated ESBL-E strains. Conclusions: Our results revealed the high occurrence of ESBL-E carriage in pregnant women, especially those who were admitted to the hospitals.

  • Differential effects of chromosome and plasmid bla<sub>CTX-M-15</sub> genes on antibiotic susceptibilities in extended-spectrum beta-lactamase-producing Escherichia coli isolates from patients with urinary tract infection.

    Yang YM, Osawa K, Kitagawa K, Hosoya S, Onishi R, Ishii A, Shirakawa T, Hirai I, Kuntaman K, Tanimoto H, Shigemura K, Fujisawa M

    International journal of urology : official journal of the Japanese Urological Association ( International Journal of Urology )  28 ( 6 ) 623 - 628   2021.06 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

     View Summary

    OBJECTIVES: To compare antibiotic susceptibilities between chromosomal and plasmid blaCTX-M-15 locations in urinary tract infection-causing extended-spectrum β-lactamases-producing Escherichia coli blaCTX-M-15 isolated in Indonesia. METHODS: A total of 84 strains identified as extended-spectrum β-lactamases-producing E. coli were isolated from patients with urinary tract infection in Indonesia in 2015. Antimicrobial susceptibility tests were performed on these strains using 18 antibiotics, and extended-spectrum β-lactamase bla genes were detected by polymerase chain reaction. Gene localization of blaCTX-M-15 -positive strains was confirmed by Southern blot hybridization, and epidemiological typing was conducted using multilocus sequence typing. RESULTS: Of 54 strains harboring the blaCTX-M-15 gene, 27 showed localization on chromosome, 20 on plasmid, and seven on chromosome and plasmid. Most multilocus sequence typing sequence types of the 27 strains with chromosomal blaCTX-M-15 were ST405 (25.9%) and ST131 (22.2%) strains, whereas the 20 strains with plasmid-blaCTX-M-15 were mostly ST410 (55.0%). CONCLUSIONS: Extended-spectrum β-lactamases-producing E. coli blaCTX-M-15 with plasmid genes show significantly higher resistant rates against piperacillin-tazobactam but lower resistant rates against chloramphenicol compared to chromosomal strains in Indonesian patients with urinary tract infection. Mechanistic investigations will be necessary to advance our knowledge of antimicrobial resistance in urinary tract infection.

  • Characterization of CTX-M-type-extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolated from Indonesian undergraduate medical students of a university in Surabaya, Indonesia.

    Rosantia S, Higa T, Yagi N, Tokunaga T, Higa S, Yakabi Y, Shirakawa T, Kuntaman K, Hirai I

    Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy ( Journal of Infection and Chemotherapy )  26 ( 6 ) 575 - 581   2020.06 [ Peer Review Accepted ]

    Type of publication: Research paper (scientific journal)

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Other Papers 【 display / non-display

SDGs 【 display / non-display

  • 東南アジアにおける薬剤耐性菌拡散状況の調査・解析