{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T02:54:38Z","timestamp":1788836078862,"version":"build-2803163510"},"reference-count":40,"publisher":"Oxford University Press (OUP)","issue":"7","license":[{"start":{"date-parts":[[2021,4,2]],"date-time":"2021-04-02T00:00:00Z","timestamp":1617321600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/academic.oup.com\/journals\/pages\/open_access\/funder_policies\/chorus\/standard_publication_model"}],"funder":[{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology of Taiwan","doi-asserted-by":"publisher","award":["MOST104-2320-B-037\u2013029"],"award-info":[{"award-number":["MOST104-2320-B-037\u2013029"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004663","name":"Ministry of Science and Technology of Taiwan","doi-asserted-by":"publisher","award":["MOST107-2320-B-037\u2013021-MY3"],"award-info":[{"award-number":["MOST107-2320-B-037\u2013021-MY3"]}],"id":[{"id":"10.13039\/501100004663","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004694","name":"Kaohsiung Medical University","doi-asserted-by":"publisher","award":["KMU-M106003"],"award-info":[{"award-number":["KMU-M106003"]}],"id":[{"id":"10.13039\/501100004694","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Kaohsiung Medical University Research Center","award":["KMU-TC109B02"],"award-info":[{"award-number":["KMU-TC109B02"]}]},{"DOI":"10.13039\/501100011645","name":"Kaohsiung Medical University Hospital","doi-asserted-by":"publisher","award":["SA10918"],"award-info":[{"award-number":["SA10918"]}],"id":[{"id":"10.13039\/501100011645","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2021,6,18]]},"abstract":"<jats:title>Abstract<\/jats:title>\n               <jats:sec>\n                  <jats:title>Objectives<\/jats:title>\n                  <jats:p>To explore the mechanisms mediating the different levels of gentamicin resistance in enterococci.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Methods<\/jats:title>\n                  <jats:p>Susceptibility testing with gentamicin and PCR of resistance determinants were performed in 149 enterococcal isolates. Genetic relatedness was characterized by MLST and PFGE analysis. Sequences of the aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia gene and its surrounding environment were determined by Illumina sequencing. Stability assays of gentamicin resistance were carried out to evaluate the probability of loss of the high-level gentamicin resistance (HLGR) phenotype.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Results<\/jats:title>\n                  <jats:p>A total of 17 (11.4%) aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia-positive enterococcal isolates (2 Enterococcus faecalis and 15 Enterococcus faecium) with non-HLGR phenotype were found. MLST analysis revealed that the 2 E. faecalis belonged to ST116 and ST618, while all the 15 E. faecium belonged to clonal complex 17. Sequence analysis demonstrated that IS1216V was inserted into the 5\u2032-end of aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia, leading to loss of HLGR phenotype. Three IS1216V insertion types were found, and type II and III were frequently found in E. faecium. Interestingly, a total of 38 aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia-positive E. faecium with HLGR phenotype also had type II or type III IS1216V insertion. Sequencing of the aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia-positive HLGR E. faecium E37 revealed that an intact aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia was located adjacent to IS1216V-disrupted aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia. In a non-antibiotic environment, E37 tended to lose HLGR phenotype with a probability of 1.57\u200a\u00d7\u200a10\u22124, which was largely attributed to homologous recombination between the intact and disrupted aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia.<\/jats:p>\n               <\/jats:sec>\n               <jats:sec>\n                  <jats:title>Conclusions<\/jats:title>\n                  <jats:p>This is first study to elucidate that the E. faecium is capable of changing its HLGR phenotype, which may contribute to adaptation to hospital environments with decreased usage of gentamicin.<\/jats:p>\n               <\/jats:sec>","DOI":"10.1093\/jac\/dkab071","type":"journal-article","created":{"date-parts":[[2021,2,25]],"date-time":"2021-02-25T17:44:17Z","timestamp":1614275057000},"page":"1689-1697","source":"Crossref","is-referenced-by-count":16,"title":["Emergence of <i>aac(6\u2032)-Ie-aph(2\u2032\u2032)-Ia<\/i>-positive enterococci with non-high-level gentamicin resistance mediated by IS<i>1216V<\/i>: adaptation to decreased aminoglycoside usage in Taiwan"],"prefix":"10.1093","volume":"76","author":[{"given":"You-Han","family":"Chen","sequence":"first","affiliation":[{"name":"Department of Microbiology and Immunology, College of Medicine, Kaohsiung Medical University, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Shang-Yi","family":"Lin","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu-Tzu","family":"Lin","sequence":"additional","affiliation":[{"name":"Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sung-Pin","family":"Tseng","sequence":"additional","affiliation":[{"name":"Department of Medical Laboratory Science and Biotechnology, College of Health Sciences, Kaohsiung Medical University, Kaohsiung, Taiwan"},{"name":"Drug Development and Value Creation Research Center, Kaohsiung Medical University, Kaohsiung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chen-Chia","family":"Chang","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, College of Medicine, Kaohsiung Medical University, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Song-Yih","family":"Yu","sequence":"additional","affiliation":[{"name":"Department of Pharmacy, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wei-Wen","family":"Hung","sequence":"additional","affiliation":[{"name":"Division of Endocrine and Metabolism, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ya-Ting","family":"Jao","sequence":"additional","affiliation":[{"name":"Infection Control Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chun-Yu","family":"Lin","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"},{"name":"Infection Control Center, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yen-Hsu","family":"Chen","sequence":"additional","affiliation":[{"name":"Division of Infectious Diseases, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan"},{"name":"School of Medicine, Graduate Institute of Medicine, Sepsis Research Center, Center of Tropical Medicine and Infectious Diseases, Kaohsiung Medical 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