{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,15]],"date-time":"2026-07-15T02:58:26Z","timestamp":1784084306868,"version":"3.55.0"},"reference-count":26,"publisher":"American Veterinary Medical Association (AVMA)","license":[{"start":{"date-parts":[[2023,9,6]],"date-time":"2023-09-06T00:00:00Z","timestamp":1693958400000},"content-version":"unspecified","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["ajvr"],"published-print":{"date-parts":[[2023,9,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n<jats:p>The fluoroquinolone antimicrobial agents, enrofloxacin and marbofloxacin, were US Food and Drug Administration (FDA) approved in the United States for use in dogs in 1988 and 1999, respectively. There have been many advances since then concerning the pharmacokinetic-pharmacodynamic (PK-PD) evaluation of fluoroquinolones, and there are data available on the susceptibility of targeted pathogens since the original approval. Using this information, the Clinical and Laboratory Standards Institute (CLSI) Veterinary Antimicrobial Susceptibility Testing Subcommittee (VAST) revised its antimicrobial susceptibility testing breakpoints. The previous breakpoints (used in older editions of CLSI standards) for enrofloxacin in dogs were susceptible (S), \u2264 0.5 \u00b5g\/mL, intermediate (I) 1\u20132 \u00b5g\/mL, and resistant (R) \u2265 4 \u00b5g\/mL. The new breakpoints are S \u2264 0.06 \u00b5g\/mL for a dose of 5 mg\/kg, 0.12 \u00b5g\/mL for a dose of 10 mg\/kg, 0.25 \u00b5g\/mL for a high dose of 20 mg\/kg, and R \u2265 0.5 \u00b5g\/mL. The breakpoints of 0.12 and 0.25 \u00b5g\/mL represent a new susceptible-dose dependent (SDD) category. For marbofloxacin, previous breakpoints were S, \u2264 1 \u00b5g\/mL, I 2 \u00b5g\/mL, and R \u2265 4 \u00b5g\/mL. The new breakpoints are S \u2264 0.12 \u00b5g\/mL for a dose of 2.8 mg\/kg, 0.25 \u00b5g\/mL for a dose of 5.5 mg\/kg (SDD), and R \u2265 0.5 \u00b5g\/mL. The new breakpoints will be published in the next edition of CLSI-Vet01(S) and deviate considerably from the prior breakpoints. Laboratories are encouraged to revise their testing standards. These changes will likely reduce the unnecessary use of these fluoroquinolones in dogs.<\/jats:p>","DOI":"10.2460\/ajvr.23.07.0159","type":"journal-article","created":{"date-parts":[[2023,9,6]],"date-time":"2023-09-06T17:23:42Z","timestamp":1694021022000},"page":"1-7","source":"Crossref","is-referenced-by-count":8,"title":["Revision of fluoroquinolone breakpoints used for interpretation of antimicrobial susceptibility testing of canine bacterial isolates"],"prefix":"10.2460","author":[{"given":"Mark G.","family":"Papich","sequence":"first","affiliation":[{"name":"College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lacie A.","family":"Gunnett","sequence":"additional","affiliation":[{"name":"Zoetis, Kalamazoo, Michigan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Brian V.","family":"Lubbers","sequence":"additional","affiliation":[{"name":"College of Veterinary Medicine, Kansas State University, Manhattan, Kansas"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1272","reference":[{"key":"B1","series-title":"Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated from Animals","year":"2023","unstructured":"CLSI. Performance Standards for Antimicrobial Disk and Dilution Susceptibility Tests for Bacteria Isolated from Animals. 7th ed. CLSI supplement VET01S. Clinical and Laboratory Standards Institute; 2023."},{"key":"B2","series-title":"Development of Quality Control Ranges, Breakpoints, and Interpretive Categories for Antimicrobial Agents Used in Veterinary Medicine","year":"2021","unstructured":"CLSI. Development of Quality Control Ranges, Breakpoints, and Interpretive Categories for Antimicrobial Agents Used in Veterinary Medicine. 4th ed; CLSI guideline VET02. Clinical and Laboratory Standards Institute; 2021."},{"issue":"6","key":"B3","series-title":"Antimicrob Agents Chemother","first-page":"2795","article-title":"Dosing regimen matters: the importance of early intervention and rapid attainment of the PK\/PD target","volume":"56","author":"Martinez MN","year":"2012","unstructured":"Martinez MN, Papich MG, Drusano GL. Dosing regimen matters: the importance of early intervention and rapid attainment of the PK\/PD target. Antimicrob Agents Chemother. 2012;56(6):2795\u20132805. doi:10.1128\/AAC.05360-11"},{"issue":"4","key":"B4","series-title":"Nature Rev Microbiol","first-page":"289","article-title":"Antimicrobial pharmacodynamics: critical interactions of \u2018bug and drug\u2019","volume":"2","author":"Drusano GL","year":"2004","unstructured":"Drusano GL. Antimicrobial pharmacodynamics: critical interactions of \u2018bug and drug\u2019. Nature Rev Microbiol. 2004;2(4):289\u2013300. doi:10.1038\/nrmicro862"},{"issue":"6","key":"B5","series-title":"J Antimicrob Chem","first-page":"1145","article-title":"Clonal spread of methicillin-resistant Staphylococcus pseudintermedius in Europe and North America: an international multicentre study","volume":"65","author":"Perreten V","year":"2010","unstructured":"Perreten V, Kadlec K, Schwarz S, et al. Clonal spread of methicillin-resistant Staphylococcus pseudintermedius in Europe and North America: an international multicentre study. J Antimicrob Chem. 2010;65(6):1145\u20131154. doi:10.1093\/jac\/dkq078"},{"key":"B6","series-title":"Fluoroquinolone Breakpoints for Enterobacteriaceae and Pseudomonas aeruginosa","year":"2019","unstructured":"CLSI. Fluoroquinolone Breakpoints for Enterobacteriaceae and Pseudomonas aeruginosa. 1st ed. CLSI rationale document MR02. Clinical and Laboratory Standards Institute; 2019."},{"issue":"6","key":"B7","series-title":"Vet Dermatol","first-page":"431","article-title":"Antimicrobial susceptibility monitoring of canine and feline skin and ear pathogens isolated from European veterinary clinics: results of the ComPath Surveillance programme","volume":"31","author":"de Jong A","year":"2020","unstructured":"de Jong A, Youala M, El Garch F, et al. Antimicrobial susceptibility monitoring of canine and feline skin and ear pathogens isolated from European veterinary clinics: results of the ComPath Surveillance programme. Vet Dermatol. 2020;31(6):431\u2013e114. doi:10.1111\/vde.12886"},{"issue":"5","key":"B8","series-title":"J Appl Microbiol","first-page":"1254","article-title":"Antimicrobial susceptibility monitoring of dermatological bacterial pathogens isolated from diseased dogs and cats across Europe (ComPath results)","volume":"121","author":"Ludwig C","year":"2016","unstructured":"Ludwig C, de Jong A, Moyaert H, et al. Antimicrobial susceptibility monitoring of dermatological bacterial pathogens isolated from diseased dogs and cats across Europe (ComPath results). J Appl Microbiol. 2016;121(5):1254\u20131267. doi:10.1111\/jam.13287"},{"issue":"3","key":"B9","series-title":"Microb Drug Resist","first-page":"391","article-title":"Antimicrobial susceptibility monitoring of bacterial pathogens isolated from urinary tract infections in dogs and cats across Europe: ComPath Results","volume":"23","author":"Moyaert H","year":"2017","unstructured":"Moyaert H, Morrissey I, de Jong A, et al. Antimicrobial susceptibility monitoring of bacterial pathogens isolated from urinary tract infections in dogs and cats across Europe: ComPath Results. Microb Drug Resist. 2017;23(3):391\u2013403. doi:10.1089\/mdr.2016.0110"},{"key":"B10","unstructured":"Zoetis Data obtained from the FDA Freedom of Information Summary. https:\/\/animaldrugsatfda.fda.gov\/adafda\/app\/search\/public\/document\/downloadFoi\/667"},{"issue":"4","key":"B11","series-title":"J Vet Pharmacol Therap","first-page":"462","article-title":"Pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin after intravenous and oral administration of enrofloxacin in dogs","volume":"16","author":"K\u00fcng K","year":"1993","unstructured":"K\u00fcng K, Riond JL, Wanner M. Pharmacokinetics of enrofloxacin and its metabolite ciprofloxacin after intravenous and oral administration of enrofloxacin in dogs. J Vet Pharmacol Therap. 1993;16(4):462\u2013468. doi:10.1111\/j.1365-2885.1993.tb00212.x"},{"issue":"1","key":"B12","series-title":"J Vet Pharmacol Therap","first-page":"1","article-title":"Comparative serum pharmacokinetics of the fluoroquinolones enrofloxacin, difloxacin, marbofloxacin, and orbifloxacin in dogs after single oral administration","volume":"25","author":"Heinen E","year":"2002","unstructured":"Heinen E. Comparative serum pharmacokinetics of the fluoroquinolones enrofloxacin, difloxacin, marbofloxacin, and orbifloxacin in dogs after single oral administration. J Vet Pharmacol Therap. 2002;25(1):1\u20135. doi:10.1046\/j.1365-2885.2002.00381.x"},{"issue":"2\u20134","key":"B13","series-title":"Vet Micro","first-page":"284","article-title":"In vitro killing of Escherichia coli, Staphylococcus pseudintermedius and Pseudomonas aeruginosa by enrofloxacin in combination with its active metabolite ciprofloxacin using clinically relevant drug concentrations in the dog and cat","volume":"155","author":"Blondeau JM","year":"2012","unstructured":"Blondeau JM, Borsos S, Blondeau LD, Blondeau BJ. In vitro killing of Escherichia coli, Staphylococcus pseudintermedius and Pseudomonas aeruginosa by enrofloxacin in combination with its active metabolite ciprofloxacin using clinically relevant drug concentrations in the dog and cat. Vet Micro. 2012;155(2\u20134):284\u2013290. doi:10.1016\/j.vetmic.2011.08.015"},{"issue":"3","key":"B14","series-title":"Res Vet Sci","first-page":"239","article-title":"In vitro antibacterial activity of enrofloxacin and ciprofloxacin in combination against Escherichia coli and staphylococcal clinical isolates from dogs","volume":"70","author":"Lautzenhiser SJ","year":"2001","unstructured":"Lautzenhiser SJ, Fialkowski JP, Bjorling D, Rosin E. In vitro antibacterial activity of enrofloxacin and ciprofloxacin in combination against Escherichia coli and staphylococcal clinical isolates from dogs. Res Vet Sci. 2001;70(3):239\u2013241. doi:10.1053\/rvsc.2001.0466"},{"issue":"2","key":"B15","series-title":"Res Vet Sci","first-page":"247","article-title":"Comparison of an HPLC and bioassay method to determine antimicrobial concentrations after intravenous and oral administration of enrofloxacin in four dogs","volume":"54","author":"K\u00fcng K","year":"1993","unstructured":"K\u00fcng K, Riond JL, Wolffram S, Wanner M. Comparison of an HPLC and bioassay method to determine antimicrobial concentrations after intravenous and oral administration of enrofloxacin in four dogs. Res Vet Sci. 1993;54(2):247\u2013248. doi:10.1016\/0034-5288(93)90065-N"},{"issue":"4","key":"B16","series-title":"J Vet Pharmacol Therap","first-page":"329","article-title":"Plasma and interstitial fluid pharmacokinetics of enrofloxacin, its metabolite ciprofloxacin, and marbofloxacin after oral administration and a constant rate intravenous infusion in dogs","volume":"28","author":"Bidgood TL","year":"2005","unstructured":"Bidgood TL, Papich MG. Plasma and interstitial fluid pharmacokinetics of enrofloxacin, its metabolite ciprofloxacin, and marbofloxacin after oral administration and a constant rate intravenous infusion in dogs. J Vet Pharmacol Therap. 2005;28(4):329\u2013341. doi:10.1111\/j.1365-2885.2005.00664.x"},{"issue":"1","key":"B17","series-title":"Pharmacotherapy: J Human Pharmacol Drug Therapy","first-page":"129","article-title":"Monte Carlo simulation in the evaluation of susceptibility breakpoints: predicting the future: insights from the society of infectious diseases pharmacists","volume":"26","author":"Ambrose PG","year":"2006","unstructured":"Ambrose PG. Monte Carlo simulation in the evaluation of susceptibility breakpoints: predicting the future: insights from the society of infectious diseases pharmacists. Pharmacotherapy: J Human Pharmacol Drug Therapy. 2006;26(1):129\u2013134. doi:10.1592\/phco.2006.26.1.129"},{"issue":"3","key":"B18","series-title":"Clin Microbiol Rev","first-page":"391","article-title":"Setting and revising antibacterial susceptibility breakpoints","volume":"20","author":"Turnidge J","year":"2007","unstructured":"Turnidge J, Paterson DL. Setting and revising antibacterial susceptibility breakpoints. Clin Microbiol Rev. 2007;20(3):391\u2013408. doi:10.1128\/CMR.00047-06"},{"key":"B19","article-title":"The National Antimicrobial Susceptibility Testing Committee for the United States. Quinolone In Vitro Susceptibility Test Interpretive Criteria Evaluations, Version 1.3","year":"2018","unstructured":"USCAST. The National Antimicrobial Susceptibility Testing Committee for the United States. Quinolone In Vitro Susceptibility Test Interpretive Criteria Evaluations, Version 1.3. 2018. http:\/\/www.uscast.org"},{"issue":"5","key":"B20","series-title":"J Vet Pharmacol Therap","first-page":"293","article-title":"Comparison of fluoroquinolone pharmacokinetic parameters after treatment with marbofloxacin, enrofloxacin, and difloxacin in dogs","volume":"23","author":"Frazier DL","year":"2000","unstructured":"Frazier DL, Thompson L, Trettien A, Evans EI. Comparison of fluoroquinolone pharmacokinetic parameters after treatment with marbofloxacin, enrofloxacin, and difloxacin in dogs. J Vet Pharmacol Therap. 2000;23(5):293\u2013302. doi:10.1046\/j.1365-2885.2000.00285.x"},{"key":"B21","series-title":"Rev Med Vet","first-page":"703","article-title":"Comparative kinetics of two orally administered fluoroquinolones in dog: enrofloxacin vs marbofloxacin","volume":"147","author":"Cester CC","year":"1996","unstructured":"Cester CC, Schneider M, Toutain PL. Comparative kinetics of two orally administered fluoroquinolones in dog: enrofloxacin vs marbofloxacin. Rev Med Vet. 1996;147:703\u2013716."},{"issue":"Suppl. 1","key":"B22","series-title":"J Vet Pharmacol Therap","first-page":"61","article-title":"Plasma pharmacokinetics and urine concentrations of enrofloxacin after oral administration of enrofloxacin in dogs","volume":"20","author":"Monlouis JD","year":"1997","unstructured":"Monlouis JD, DeJong A, Limet A, Richez P. Plasma pharmacokinetics and urine concentrations of enrofloxacin after oral administration of enrofloxacin in dogs. J Vet Pharmacol Therap. 1997;20(Suppl. 1):61\u201363."},{"issue":"4","key":"B23","series-title":"Vet Thera: Res Applied Vet Med","first-page":"409","article-title":"Plasma concentrations of enrofloxacin and its active metabolite ciprofloxacin in dogs following single oral administration of enrofloxacin at 7.5, 10, or 20 mg\/kg","volume":"3","author":"Boothe DM","year":"2002","unstructured":"Boothe DM, Boeckh A, Boothe HW, et al. Plasma concentrations of enrofloxacin and its active metabolite ciprofloxacin in dogs following single oral administration of enrofloxacin at 7.5, 10, or 20 mg\/kg. Vet Thera: Res Applied Vet Med. 2002;3(4):409\u2013419."},{"key":"B24","series-title":"Frontiers Pharmacol","first-page":"306","article-title":"Evaluation of marbofloxacin in beagle dogs after oral dosing: preclinical safety evaluation and comparative pharmacokinetics of two different tablets","volume":"9","author":"Lei Z","year":"2018","unstructured":"Lei Z, Liu Q, Yang B, et al. Evaluation of marbofloxacin in beagle dogs after oral dosing: preclinical safety evaluation and comparative pharmacokinetics of two different tablets. Frontiers Pharmacol. 2018;9:306. doi:10.3389\/fphar.2018.00306"},{"issue":"1","key":"B25","series-title":"J Vet Pharmacol Therap","first-page":"56","article-title":"Pharmacokinetics of marbofloxacin in dogs after oral and parenteral administration","volume":"19","author":"Schneider M","year":"1996","unstructured":"Schneider M, Thomas V, Boisrame B, Deleforge J. Pharmacokinetics of marbofloxacin in dogs after oral and parenteral administration. J Vet Pharmacol Therap. 1996;19(1):56\u201361. doi:10.1111\/j.1365-2885.1996.tb00009.x"},{"issue":"5","key":"B26","series-title":"J Vet Pharmacol Therap","first-page":"440","article-title":"Pseudomonas aeruginosa susceptibility, antibiogram and clinical interpretation, and antimicrobial prescribing behaviors for dogs with otitis in the Midwestern United States","volume":"45","author":"KuKanich KS","year":"2022","unstructured":"KuKanich KS, Bagladi-Swanson M, KuKanich B. Pseudomonas aeruginosa susceptibility, antibiogram and clinical interpretation, and antimicrobial prescribing behaviors for dogs with otitis in the Midwestern United States. J Vet Pharmacol Therap. 2022;45(5):440\u2013449. doi:10.1111\/jvp.13077"}],"container-title":["American Journal of Veterinary Research"],"original-title":[],"link":[{"URL":"https:\/\/avmajournals.avma.org\/view\/journals\/ajvr\/aop\/ajvr.23.07.0159\/ajvr.23.07.0159.xml","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/avmajournals.avma.org\/view\/journals\/ajvr\/aop\/ajvr.23.07.0159\/ajvr.23.07.0159.xml","content-type":"text\/html","content-version":"vor","intended-application":"syndication"},{"URL":"https:\/\/avmajournals.avma.org\/view\/journals\/ajvr\/aop\/ajvr.23.07.0159\/ajvr.23.07.0159.xml","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,6]],"date-time":"2023-09-06T17:23:42Z","timestamp":1694021022000},"score":1,"resource":{"primary":{"URL":"https:\/\/avmajournals.avma.org\/view\/journals\/ajvr\/aop\/ajvr.23.07.0159\/ajvr.23.07.0159.xml"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,9,6]]},"references-count":26,"URL":"https:\/\/doi.org\/10.2460\/ajvr.23.07.0159","relation":{},"ISSN":["0002-9645","1943-5681"],"issn-type":[{"value":"0002-9645","type":"print"},{"value":"1943-5681","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,9,6]]}}}