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Multidrug-Resistant ESBL/AmpC-Producing Klebsiella pneumoniae Isolated from Healthy Thoroughbred Racehorses in Japan Eddy, Sukmawinata エディ, スクマウィナタ エディ, スクマウィナタ Eddy エディ エディ Sukmawinata スクマウィナタ スクマウィナタ 90529190 上村, 涼子 ウエムラ, リョウコ Uemura, Ryoko 上村 ウエムラ Uemura 涼子 リョウコ Ryoko 宮崎大学 University of Miyazaki Sato, Wataru Sato Wataru Htun, Myo Thu Htun Myo Thu 10305063 Sueyoshi, Masuo 末吉, 益雄 スエヨシ, マスオ Sueyoshi 末吉 スエヨシ Masuo 益雄 マスオ open access © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). extended-spectrum β-lactamase AmpC β-lactamase Klebsiella pneumoniae horse multidrug resistance Extended-spectrum β-lactamase (ESBL)- and AmpC β-lactamase (AmpC)-producing Klebsiella spp. have become a major health problem, leading to treatment failure in humans and animals. This study aimed to evaluate the presence of ESBL/AmpC-producing Klebsiella spp. isolated from racehorses in Japan. Feces samples from 212 healthy Thoroughbred racehorses were collected from the Japan Racing Association Training Centers between March 2017 and August 2018. ESBL/AmpC-producing Klebsiella spp. were isolated using selective medium containing 1 µg/mL cefotaxime. All isolates were subjected to bacterial species identification (MALDI-TOF MS), antimicrobial susceptibility test (disk diffusion test), characterization of resistance genes (PCR), conjugation assay, and genetic relatedness (multilocus sequence typing/MLST). Twelve ESBL/AmpC-producing Klebsiella pneumoniae (ESBL/AmpC-KP) were isolated from 3.3% of horse samples. Antimicrobial resistance profiling for 17 antimicrobials showed all ESBL/AmpC-KP were multidrug-resistant (MDR). Only 1 isolate was confirmed as an ESBL producer (blaCTX-M-2-positive), whereas the other 11 isolates were plasmid-mediated AmpC (pAmpC) producers (blaCMY positive). On the basis of MLST analysis, the ESBL-KP isolate was identified as sequence type (ST)-133 and four different STs among AmpC-KP isolates, ST-145, ST-4830, ST-4831, and ST-4832, were found to share six of the seven loci constituting a single-locus variant. This is the first study to show K. pneumoniae carrying MDR pAmpC isolated from a racehorse. Citation: Sukmawinata, E.; Uemura, R.; Sato, W.; Thu Htun, M.; Sueyoshi, M. Multidrug-Resistant ESBL/AmpC-Producing Klebsiella pneumoniae Isolated from Healthy Thoroughbred Racehorses in Japan. Animals 2020, 10, 369. https://doi.org/10.3390/ani10030369 MDPI 2020-02-25 eng journal article VoR http://hdl.handle.net/10458/0002000158 https://miyazaki-u.repo.nii.ac.jp/records/2000158 https://doi.org/10.3390/ani10030369 Animals 10 3 369 https://miyazaki-u.repo.nii.ac.jp/record/2000158/files/4_Multidrug-Resistant ESBL_AmpC-Producing Klebsiella pneumoniae Isolated from Healthy Thoroughbred Racehorses in Japan.pdf application/pdf 657 KB 2023-10-26