{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,31]],"date-time":"2026-07-31T22:29:32Z","timestamp":1785536972044,"version":"3.56.0"},"reference-count":48,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2023,4,21]],"date-time":"2023-04-21T00:00:00Z","timestamp":1682035200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"projects UIDP\/CVT\/00772\/2020 (CECAV)"},{"name":"LA\/P\/0059\/2020"},{"name":"UIDB\/AGR\/04033\/2020 (CITAB)"},{"name":"Portuguese Foundation for Science and Technology (FCT)"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Antibiotics"],"abstract":"<jats:p>Horses are considered as reservoirs of multidrug resistant bacteria that can be spread through the environment and possibly to humans. The aim of this study was to characterize the oral Gram-negative microbiota of healthy horses and evaluate their antimicrobial susceptibility profile in a One Health approach. For this purpose, samples were collected from the gingival margin of healthy horses, free of antimicrobial therapy, cultured in selective mediums, identified, and tested for antimicrobial susceptibility. Fifty-five Gram-negative isolates were identified, with 89.5% being zoonotic and 62% affecting humans, which were also found commonly in the environment. Forty-eight isolates (96%) were MDR. The phenotypic resistance presented as higher to macrolides (81.8%), \u03b2-lactams (55.4%), and quinolones (50%), and lower to sulfonamides (27.3%), tetracyclines, and amphenicols (both with 30.9%). In total, 51.5% of the isolates presented resistance to carbapenems. In addition to being the first report on the commensal oral microbiota of horses and respective susceptibility profile, this study highlights the horse as a valuable sentinel that can control the evolution and transmission of multidrug-resistant bacteria between the \u201cOne Health triad\u201d since it is in contact with humans, other animals, and the environment, in different geographic locations.<\/jats:p>","DOI":"10.3390\/antibiotics12040792","type":"journal-article","created":{"date-parts":[[2023,4,21]],"date-time":"2023-04-21T03:01:48Z","timestamp":1682046108000},"page":"792","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":11,"title":["Equine Gram-Negative Oral Microbiota: An Antimicrobial Resistances Watcher?"],"prefix":"10.3390","volume":"12","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7328-2123","authenticated-orcid":false,"given":"Jos\u00e9","family":"Pimenta","sequence":"first","affiliation":[{"name":"Department of Veterinary Sciences, Antimicrobials, Biocides & Biofilms Unit (A2BUnit), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"CECAV-Veterinary and Animal Research Center and Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ana Rita","family":"Pinto","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, Antimicrobials, Biocides & Biofilms Unit (A2BUnit), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"CITAB-Centre for the Research and Technology of Agro-Environmental and Biological Sciences and Institute for Innovation, Capacity Building and Sustainability of Agri-Food Production (Inov4Agro), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7492-4965","authenticated-orcid":false,"given":"Maria Jos\u00e9","family":"Saavedra","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, Antimicrobials, Biocides & Biofilms Unit (A2BUnit), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"CECAV-Veterinary and Animal Research Center and Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"CITAB-Centre for the Research and Technology of Agro-Environmental and Biological Sciences and Institute for Innovation, Capacity Building and Sustainability of Agri-Food Production (Inov4Agro), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6336-6515","authenticated-orcid":false,"given":"M\u00e1rio","family":"Cotovio","sequence":"additional","affiliation":[{"name":"Department of Veterinary Sciences, Antimicrobials, Biocides & Biofilms Unit (A2BUnit), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"},{"name":"CECAV-Veterinary and Animal Research Center and Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), University of Tr\u00e1s-os-Montes and Alto Douro, 5000-801 Vila Real, Portugal"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,4,21]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"49","DOI":"10.1186\/s13567-016-0333-1","article-title":"The Microbiome Associated with Equine Periodontitis and Oral Health","volume":"47","author":"Kennedy","year":"2016","journal-title":"Vet. 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