Comparison of bacteria cultured during a total ear canal ablation and subsequent incisional dehiscence in 12 dogs.

Objective: To compare bacteria cultured at the time of total ear canal ablation (TECA) to bacteria cultured from post-TECA incisional dehiscence.

Study design: Multicenter retrospective case series.

Animal population: Dogs (n = 12) with incisional dehiscence following TECA.

Methods: Medical records of dogs that had a TECA between August 1, 2015, and August 1, 2023, with a subsequent incisional dehiscence within 5 weeks of surgery were reviewed. Aerobic cultures were performed at the time of surgery and time of incisional dehiscence.

Results: The most common organisms cultured from TECA samples included Staphylococcus spp. (5/12, 41.7%), Enterococcus spp. (3/12, 25%), Streptococcus spp. (3/12, 25%), Escherichia coli (2/12, 16.7%), and Corynebacterium spp. (2/12, 16.7%). The organisms most commonly isolated from incisional dehiscences were Staphylococcus spp. (10/12, 83.3%) and Escherichia coli (5/12, 41.7%). The median time for incisional dehiscence was 11.5 days postoperatively (range, 2-34 days). The same single bacteria species, Staphylococcus schleiferi, was identified from the TECA and incisional dehiscence cultures in only one dog (1/12, 8.3%). In 6/12 (50%) dogs, the same bacteria were cultured before or during TECA and at the time of incisional dehiscence, but additional organisms were also identified. Antibiotic susceptibility patterns were different in four of seven dogs where the same bacteria were cultured prior to and during incisional dehiscence.

Conclusion: Cultures performed during TECA were not predictive of culture results at the time of dehiscence. Antibiotic susceptibility patterns often changed when the same organism was cultured prior to and at incisional dehiscence.

Clinical significance: Repeating cultures is essential to treat infectious incisional dehiscence following TECA appropriately.