|Thirty dogs with end-stage otitis externa undergoing unilateral total ear canal ablation were enrolled.
The dogs were randomized to one of four enrofloxacin-treatment groups or to the control group.
Each dog in the treatment groups received two intravenous doses of enrofloxacin prior to surgical removal of the middle-ear tissue while the control group did not receive any enrofloxacin.
One dog was excluded from the study as no middle-ear tissue was removed during surgery.
Twenty-four dogs were in the enrofloxacin-treatment groups and five dogs were in the control group.
In 12 of 29 dogs (41.4%), 14 of 82 (17.1%) of bacteria had discrepancies in DDT results for enrofloxacin and ciprofloxacin.
Discrepancies between the control group and treatment groups were not significantly different even though the percentage of discrepancies for the combined treatment group was 19.4% compared to 6.7% for the control group.
In this study, ciprofloxacin DDT results were not an accurate indicator of the in vitro susceptibility of enrofloxacin for bacteria isolated from the middle-ear tissue of dogs with end-stage otitis.
Source: Cole LK, Kwochka KW, Hillier A, Kowalski JJ, Smeak DD, Kelbick NT. (2006): Ciprofloxacin as a representative of disk diffusion in vitro susceptibility of enrofloxacin for bacterial organisms from the middle-ear tissue of dogs with end-stage otitis externa. In: Vet Dermatol. 2006 Apr;17(2):128-33.