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Its use provides an alternative approach to address the global issue of antimicrobial resistance and enhance antimicrobial stewardship.<\/jats:p><\/jats:sec><jats:sec><jats:title>Hypothesis\/Objectives<\/jats:title><jats:p>To determine the antimicrobial activity of a panel of potential antimicrobial adjuvants against common pathogens associated with canine otitis externa (OE).<\/jats:p><\/jats:sec><jats:sec><jats:title>Animals\/Isolates<\/jats:title><jats:p>A number of type strains and clinical isolates (n\u00a0=\u00a0110) from canine OE were tested including<jats:italic>Staphylococcus pseudintermedius,<\/jats:italic>\u03b2\u2010haemolytic<jats:italic>Streptococcus<\/jats:italic>spp.,<jats:italic>Pseudomonas aeruginosa<\/jats:italic>,<jats:italic>Proteus mirabilis<\/jats:italic>and<jats:italic>Malassezia pachydermatis<\/jats:italic>.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods and materials<\/jats:title><jats:p>Antimicrobial activities of monolaurin, monocaprin,<jats:italic>N<\/jats:italic>\u2010acetylcysteine (NAC), polymyxin B nonapeptide, Tris\u2010EDTA, Tris\u2010HCL and disodium EDTA were tested using microdilution methodology according to CLSI guidelines.<\/jats:p><\/jats:sec><jats:sec><jats:title>Results<\/jats:title><jats:p><jats:italic>N<\/jats:italic>\u2010acetylcysteine, Tris\u2010EDTA and disodium EDTA had antimicrobial activity against both type strains and otic pathogens. The other adjuvants tested had limited to no efficacy. NAC had a minimal inhibitory concentration (MIC) range of 2,500\u201310,000\u00a0\u03bcg\/mL for the various organisms.<jats:italic>Pseudomonas aeruginosa<\/jats:italic>isolates were eight times more susceptible to disodium EDTA in the presence of Tris\u2010HCL in comparison to disodium EDTA alone.<jats:italic>Malassezia pachydermatis<\/jats:italic>isolates were most susceptible to Tris\u2010EDTA (MIC<jats:sub>90<\/jats:sub>\u00a0=\u00a0190\/60\u00a0\u03bcg\/mL) and disodium EDTA (MIC<jats:sub>90<\/jats:sub>\u00a0=\u00a0120\u00a0\u03bcg\/mL).<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusions and clinical relevance<\/jats:title><jats:p><jats:italic>N<\/jats:italic>\u2010acetylcysteine, Tris\u2010EDTA and disodium EDTA have intrinsic antimicrobial activity and represent promising adjuvants that could be used to enhance the efficacy of existing antibiotics against Gram\u2010negative and multidrug\u2010resistant bacterial infections. These agents could be combined with other antimicrobial agents in a multimodal approach for mixed ear infections in dogs.<\/jats:p><\/jats:sec>","DOI":"10.1111\/vde.12712","type":"journal-article","created":{"date-parts":[[2018,12,13]],"date-time":"2018-12-13T08:24:44Z","timestamp":1544689484000},"page":"133","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["<i>In vitro<\/i>antimicrobial activity of seven adjuvants against common pathogens associated with canine otitis externa"],"prefix":"10.1111","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-9415-9893","authenticated-orcid":false,"given":"Wei Yee","family":"Chan","sequence":"first","affiliation":[{"name":"Australian Centre for Antimicrobial Resistance Ecology School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia 5371 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manouchehr","family":"Khazandi","sequence":"additional","affiliation":[{"name":"Australian Centre for Antimicrobial Resistance Ecology School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia 5371 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Elizabeth E.","family":"Hickey","sequence":"additional","affiliation":[{"name":"Australian Centre for Antimicrobial Resistance Ecology School of Animal and Veterinary Sciences The University of Adelaide Roseworthy South Australia 5371 Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Stephen W.","family":"Page","sequence":"additional","affiliation":[{"name":"Luoda Pharma Pty. 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