{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T23:45:57Z","timestamp":1792799157733,"version":"4.5.0"},"reference-count":48,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,1,27]],"date-time":"2026-01-27T00:00:00Z","timestamp":1769472000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:p>\n                    Colistin resistance mediated by the plasmid-borne\n                    <jats:italic>mcr-1<\/jats:italic>\n                    gene presents a significant challenge in both human and veterinary medicine. While colistin-resistant bacteria have been reported in food-producing animals and humans,\n                    <jats:italic>mcr-1<\/jats:italic>\n                    -harboring strains remain relatively underreported in companion animals, particularly in South Korea. In this study, a colistin-resistant\n                    <jats:italic>Escherichia coli<\/jats:italic>\n                    strain Z1324PEC0026 was isolated from a clinically healthy companion dog owned by a veterinary nurse, which exhibited resistance to multiple antimicrobials, including colistin, \u03b2-lactams, aminoglycosides, tetracyclines, and phenicols. Its genome harbored two plasmids: a 33.9\u202fkb IncX4 plasmid pEC027-3 carrying\n                    <jats:italic>mcr-1<\/jats:italic>\n                    gene with a high conjugation frequency, 4.64\u202f\u00d7\u202f10\n                    <jats:sup>\u22122<\/jats:sup>\n                    per recipient cell, and another plasmid pEC027-2 carrying additional resistance genes such as\n                    <jats:italic>bla<\/jats:italic>\n                    <jats:sub>CTX-M-55<\/jats:sub>\n                    ,\n                    <jats:italic>bla<\/jats:italic>\n                    <jats:sub>OXA-10<\/jats:sub>\n                    ,\n                    <jats:italic>qnrS1<\/jats:italic>\n                    ,\n                    <jats:italic>dfrA14<\/jats:italic>\n                    ,\n                    <jats:italic>aph(3\u201d)-Ia<\/jats:italic>\n                    ,\n                    <jats:italic>aadA1<\/jats:italic>\n                    ,\n                    <jats:italic>cmlA1<\/jats:italic>\n                    ,\n                    <jats:italic>arr-2<\/jats:italic>\n                    , and\n                    <jats:italic>tet(A)<\/jats:italic>\n                    . The genetic structure of pEC027-3 exhibited high synteny with global IncX4 plasmids but showed divergence from\n                    <jats:italic>mcr-1<\/jats:italic>\n                    -carrying plasmids previously reported in South Korea, suggesting an independent origin. The presence of a transferable\n                    <jats:italic>mcr-1<\/jats:italic>\n                    -harboring IncX4 plasmid in a healthy dog with no prior colistin exposure implies the risk of silent dissemination of antimicrobial resistance.\n                  <\/jats:p>","DOI":"10.3389\/fvets.2025.1746399","type":"journal-article","created":{"date-parts":[[2026,1,27]],"date-time":"2026-01-27T15:37:01Z","timestamp":1769528221000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":4,"title":["Case Report: Transferable IncX4 plasmid carrying mcr-1 in colistin-resistant Escherichia coli from a healthy pet dog in South Korea"],"prefix":"10.3389","volume":"12","author":[{"given":"Jae Young","family":"Oh","sequence":"first","affiliation":[{"name":"Division of Biotechnology, Jeonbuk National University","place":["Iksan, Republic of Korea"]},{"name":"Advanced Institute of Environment and Bioscience, Jeonbuk National University","place":["Iksan, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Su Min","family":"Kwak","sequence":"additional","affiliation":[{"name":"Division of Biotechnology, Jeonbuk National University","place":["Iksan, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joo Yeol","family":"Kim","sequence":"additional","affiliation":[{"name":"Division of Biotechnology, Jeonbuk National University","place":["Iksan, Republic of Korea"]},{"name":"Advanced Institute of Environment and Bioscience, Jeonbuk National University","place":["Iksan, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Woong-Bin","family":"Ro","sequence":"additional","affiliation":[{"name":"Department of Veterinary Emergency and Critical Care Medicine, College of Veterinary Medicine, Chonnam National University","place":["Gwangju, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kwang Jun","family":"Lee","sequence":"additional","affiliation":[{"name":"Division of Zoonotic and Vector Borne Disease Research, National Institute of Health","place":["Cheongju, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jong-Chan","family":"Chae","sequence":"additional","affiliation":[{"name":"Division of Biotechnology, Jeonbuk National University","place":["Iksan, Republic of Korea"]},{"name":"Advanced Institute of Environment and Bioscience, Jeonbuk National University","place":["Iksan, Republic of Korea"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,1,27]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"557","DOI":"10.1128\/CMR.00064-16","article-title":"Polymyxins: antibacterial activity, susceptibility testing, and resistance mechanisms encoded by plasmids or 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