In the Laboratory of Microbiology, Department of Clinical Laboratory Sciences, we study several bacterial species, such as Enterobacteriaceae and genus Aeromonas, which are obtained from healthcare-associated facilities, healthy individuals, food items, livestock, and the environment, both domestic and international. In order to determine what bacterial species are distributed and what kinds of molecular characters those bacteria possess, molecular microbiological methods, including PCR and long read sequencing using the Nanopore sequencer, are adopted. In addition, we have established Escherichia coli model system for analyzing molecular mechanisms including antimicrobial resistance of certain bacteria
- Yamaguchi T, Kawahara R, Hamamoto K, Hirai I, Khong DT, Nguyen TN, Tran HT, Motooka D, Nakamura S, Yamamoto Y: High Prevalence of Colistin-Resistant Escherichia coli with Chromosomally Carried mcr-1 in Healthy Residents in Vietnam.
mSphere. 2020, 5(2). pii: e00117-20. doi: 10.1128/mSphere.00117-20.
- Hamamoto K, Tokunaga T, Yagi N, Hirai I: Characterization of blaCTX-M-14 Transposition From Plasmid to Chromosome in Escherichia coli Experimental Strain. Int J Med Microbiol. 2020, 310(2):151395. doi: 10.1016/j.ijmm.2020.151395.
- Miyagi K, Hirai I: A survey of extended-spectrum β-lactamase-producing Enterobacteriaceae in environmental water in Okinawa Prefecture of Japan and relationship with indicator organisms. Environ Sci Pollut Res Int. 2019, 26(8):7697-7710. doi: 10.1007/s11356-019-04189-z.
- Yamamoto Y, Kawahara R, Fujiya Y, Sasaki T, Hirai I, Khong DT, Nguyen TN, Nguyen BX: Wide dissemination of colistin-resistant Escherichia coli with the mobile resistance gene mcr in healthy residents in Vietnam. J Antimicrob Chemother. 2019, 74(2):523-524. doi: 10.1093/jac/dky435.
- Higa S, Sarassari R, Hamamoto K, Yakabi Y, Higa K, Koja Y, Hirai I: Characterization of CTX-M type ESBL-producing Enterobacteriaceae isolated from asymptomatic healthy individuals who live in a community of the Okinawa prefecture, Japan. J Infect Chemother. 2018, 25(4):314-317. doi: 10.1016/j.jiac.2018.09.005.
- Miyagi K, Sano K, Hirai I. Sanitary evaluation of domestic water supply facilities with storage tanks and detection of Aeromonas, enteric and related bacteria in domestic water facilities in Okinawa Prefecture of Japan.
Water Res. 119: 171-177, 2017. doi: 10.1016/j.watres.2017.04.002.
- Hamamoto K, Ueda S, Toyosato T, Yamamoto Y, Hirai I: High prevalence of chromosomal blaCTX-M-14 in Escherichia coli isolates possessing blaCTX-M-14. Antimicrob Agents Chemother. 2016, 60(4):2582-2584.
- Bui TM, Hirai I, Ueda S, Bui TK, Hamamoto K, Toyosato T, Le DT, Yamamoto Y: Characterization of Escherichia coli producing CTX-M-type extended-spectrum β-lactamase carriage in healthy Vietnamese individuals. Antimicrob Agents Chemother. 2015, 59(10), 6611-6614.
- Hamamoto K, Ueda S, Yamamoto Y, Hirai I: Evaluation of three-marker GIG-EM phylogenetic typing of Escherichia coli isolates of various genetic backgrounds. J Clin Microbiol. 2015, 53(6):1848-1853.
- Ueda S, Bui TK, Bui TM, Hirai I, Le DT, Yamamoto Y: Limited transmission of blaCTX-M-9-type positive Escherichia coli between humans and poultry in Vietnam. Antimicrob Agents Chemother. 2015, 59(6):3574-3577.