Clinical response to 2 protocols of aerosolized gentamicin in 46 dogs with Bordetella bronchiseptica infection (2012-2018)

Abstract

Background: Bordetella bronchiseptica (Bb) infection commonly causes respiratory disease in dogs. Gentamicin delivered by aerosol maximizes local drug delivery without systemic absorption but clinical response to protocols remains undetermined. Objectives: To compare the clinical response to 2 protocols of aerosolized delivery of gentamicin in bordetellosis. Animals: Forty-six dogs with Bb infection confirmed by culture or quantitative polymerase chain reaction on bronchoalveolar lavage. Methods: Retrospective study. Administration of aerosolized gentamicin for ≥10 minutes q12h for ≥3 weeks using 4 mg/kg diluted with saline (group 1) or undiluted 5% solution (group 2). Clinical response firstly assessed after 3-4 weeks and treatment pursued by 3-weeks increments if cure not reached. Cure defined as absence of cough persisting at least a week after treatment interruption. Results: Demographic data were similar between both groups. Clinical cure at 3-4 weeks was more frequently observed with the use of undiluted solution (19/33 vs 3/13 dogs, P =.03) in association with a shorter median duration of treatment (4 vs 6 weeks, P =.01). Dogs from group 2 having less than 1000 cells/μL in lavage were also more likely to be cured at 3-4 weeks than dogs with more than 1000 cells/μL [9/9 vs 10/19, P =.006] and median duration of treatment in that subgroup of animals was reduced (3 vs 5 weeks, P =.02). Conclusion and Clinical Importance: Aerosolized delivery of gentamicin seems effective for inducing clinical cure in Bb infection. Clinical response appears better using undiluted 5% solution, particularly in the subgroup of dogs having less than 1000 cells/μL in lavage.