title: Antimicrobial resistance and pharmacodynamics of canine and feline pathogenic E. coli in the United States.
abstract: Percent resistance and minimum inhibitory concentrations (MIC) were described for canine (n = 301) and feline (n = 75) pathogenic Escherichia coli (E. coli) isolates solicited during May 2005 to Sep 2005 from the Clinical Pharmacology Laboratory at Auburn University (n = 165) or commercial diagnostic laboratories ([CDL]; n = 211) from four regions in the USA. Drugs tested were amoxicillin (AMX), amoxicillin trihydrate/clavulanate potassium (AMXC), cefpodoxime (CFP), doxycycline (DXY), enrofloxacin (ENR), gentamicin (GM) and trimethoprim-sulfamethoxazole (TMS). Urinary isolates were most common (n = 174). Percent resistance was greatest for isolates from the respiratory tract, urine, and skin compared with the ear. Resistance was also greatest for samples sent from the south and central states compared with the western states (P ≤ 0.001). Percent resistance by drug was AMX (46 ± 2.6%) > AMXC (37 ± 2.5%) > CFP (21.8 ± 2%) = DXY (22 ± 2.1%) = ENR (20 ± 2.1%) = TMS (19 ± 2%) > GM (12 ± 1.7%). There was a significant difference in resistance between the different antibiotic drugs (P ≤ 0.001). Population MIC distributions were bimodal, and MICs were highest in samples from the southern states (P ≤ 0.001). E. coli resistance may limit its empirical treatment. For susceptible isolates, AMX and AMXC may be least effective and TMS most effective.
authors.affiliation: Department of Anatomy, Physiology and Pharmacology, Auburn University, AL, USA. boothdm@auburn.edu
authors.forename: Dawn
authors.initials: D
authors.lastname: Boothe
authors.forename: Tim
authors.initials: T
authors.lastname: Smaha
authors.forename: D Mark
authors.initials: DM
authors.lastname: Carpenter
authors.forename: Bashar
authors.initials: B
authors.lastname: Shaheen
authors.forename: Terri
authors.initials: T
authors.lastname: Hatchcock
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002371:Cat Diseases / Q000188:drug therapy / Q000382:microbiology*; D002415:Cats; D004283:Dog Diseases / Q000188:drug therapy / Q000382:microbiology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D024881:Drug Resistance, Bacterial; D004926:Escherichia coli / Q000187:drug effects* / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000188:drug therapy / Q000662:veterinary*; D008826:Microbial Sensitivity Tests / Q000662:veterinary; D015995:Prevalence; D016896:Treatment Outcome; D014481:United States
chemical_list: D000900:Anti-Bacterial Agents