{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,13]],"date-time":"2026-06-13T03:48:58Z","timestamp":1781322538241,"version":"3.54.1"},"reference-count":27,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2022,4,7]],"date-time":"2022-04-07T00:00:00Z","timestamp":1649289600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004608","name":"Natural Science Foundation of Jiangsu Province","doi-asserted-by":"publisher","award":["BK20190261"],"award-info":[{"award-number":["BK20190261"]}],"id":[{"id":"10.13039\/501100004608","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32102728"],"award-info":[{"award-number":["32102728"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["32102675"],"award-info":[{"award-number":["32102675"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Exploration and Disruptive Innovation Projects of Jiangsu Academy of Agricultural Sciences","award":["ZX(21)1224"],"award-info":[{"award-number":["ZX(21)1224"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Mycoplasma hyorhinis is ubiquitous in swine, and it is a common pathogen of swine that causes polyserositis, arthritis, and maybe pneumonia. Fluoroquinolones are effective antimicrobials used for the treatment of mycoplasmal infection. However, a decrease in fluoroquinolones susceptibility in mycoplasma was observed. The molecular mechanisms have been studied in many mycoplasma species, while the mechanism in M. hyorhinis is still unknown. This study aimed to illustrate the in vitro development of fluoroquinolone resistance in M. hyorhinis and unveil the resistance mechanisms in both in vitro selected mutants and field strains. Seven ciprofloxacin-sensitive M. hyorhinis isolates were chosen to induce the fluoroquinolone resistance in vitro, and the point mutations in the quinolone resistance-determining regions (QRDRs) were characterized. The substitutions first occurred in ParC, resulting in a 2- to 8-fold increase in resistance, followed by additional mutations in GyrA and\/or ParE to achieve a 32-fold increase. The mutations occurred in hot spots of QRDRs, and they were diverse and variable, including five in ParC (Ser80Phe, Ser80Tyr, Phe80Tyr, Glu84Gly, and Glu84Lys), four in GyrA (Ala83Val, Ser84Pro, Asp87Tyr, and Asp87Asn) and one in ParE (Glu470Lys). Target mutations in field strains were observed in the ParC (Ser80Phe, Ser81Pro, and Glu84Gln) of isolates with MICCIP = 2 \u03bcg\/mL. This study characterized the point mutations in the QRDRs of M. hyorhinis and could be useful for the rapid detection of fluoroquinolone resistance in M. hyorhinis field isolates.<\/jats:p>","DOI":"10.3390\/antibiotics11040494","type":"journal-article","created":{"date-parts":[[2022,4,7]],"date-time":"2022-04-07T13:39:51Z","timestamp":1649338791000},"page":"494","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":19,"title":["Characterization of Mutations in DNA Gyrase and Topoisomerase IV in Field Strains and In Vitro Selected Quinolone-Resistant Mycoplasma hyorhinis Mutants"],"prefix":"10.3390","volume":"11","author":[{"given":"Jun","family":"Li","sequence":"first","affiliation":[{"name":"Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing 210040, China"},{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanna","family":"Wei","sequence":"additional","affiliation":[{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jia","family":"Wang","sequence":"additional","affiliation":[{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yao","family":"Li","sequence":"additional","affiliation":[{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Guoqing","family":"Shao","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing 210040, China"},{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhixin","family":"Feng","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing 210040, China"},{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Qiyan","family":"Xiong","sequence":"additional","affiliation":[{"name":"Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Food Safety and Nutrition, Jiangsu Academy of Agricultural Sciences, Nanjing 210040, China"},{"name":"Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing 210014, China"},{"name":"College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210014, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2022,4,7]]},"reference":[{"key":"ref_1","first-page":"413","article-title":"A Pleuropneumonia-like Organism Associated with Infectious Atrophic Rhinitis of Swine","volume":"17","author":"Carter","year":"1953","journal-title":"Can. 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