Pyoderma associated with canine demodicosis could resolve without antibiotic therapy

SOFÍA MARTÍNEZ; CLAUDIO CACCIATO; FERNANDO FOGEL; LAURA MATÉ; SERGIO SÁNCHEZ BRUNI; MARÍA JOSÉ DEL SOLE

Buenos Aires

Jornada; 1ras. Jornadas INCLIVET (Instituto de Investigaciones Clínicas Veterinarias). FCV - UBA; 2021

Universidad Nacional de Buenos Aires

Generalized canine demodicosis is the result of an overpopulation of mites of Demodex spp. commonly associated with infection by Staphylococcus spp., normal inhabitants of the skin of most mammals. Both microorganisms proliferate within the hair follicles causing follicular hyperkeratosis in the head, trunk and legs. Dermatological examination reveals signs such as erythema, alopecia, folliculitis and furunculosis. Generally, systemic antibiotics are used to treat bacterial infection secondary to proliferation of mites. In fact, the latest Clinical Practice Guidelines on Demodicosis Treatment (2011) recommend specific oral and topical antibiotic therapy in all dogs with generalized demodicosis up to 1 or 2 weeks after clinical and microscopic resolution of the skin infection. However, bacterial resistance is currently a concern for public and animal health, reserving systemic antibiotic therapies only for animals that strictly require it. The main goal of this study was to assess the clinical evolution and bacteriological cure of canines with generalized demodicosis treated only with acaricides. For this purpose, 4 patients with pustular demodicosis were admitted for their attention at the Teaching Hospital of Small Animals (HEPA). On day 0, the animals were clinically evaluated by a clinical score and skin samples were obtained by swabs from lesions. Then, patients initiated a non-antibiotic treatment as follow: 2 (two) dogs were treated with afoxolaner 2.7-6.9 mg/kg on day 0 and day 28, and 2 (two) dogs were treated with oral ivermectin at a dose of 0.5 mg/kg/24 h for 63 days. On days 14, 35 and 56 post-treatment, clinical score were recorded and sample swabs from skin lesions were obtained. Sample swabs were stored in Stuart medium up to overnight growth on Tryptic Soy Agar medium supplemented with 10% sterile bovine blood. The phenotypic identification bacterial strains was performed by conventional biochemical techniques. Clinical score (mean +/- DE) decreased considerably throughout the treatment as follow: 37.8 (3.3), 35.0 (3.7), 14.3 (2.9), and 4.3 (1.9) on day 0, 14, 35 and 56, respectively. Staphylococcus spp. were isolated from skin samples in all dogs on days 0 and 14 post treatment. However, the cultures became negative in three of four dogs at day 35, negativizing all dogs at day 56 post-treatment. In conclusion, these preliminary results propose that pyoderma associated with canine demodicosis could resolve clinically and bacteriologically with single acaricidal therapy, avoiding systemic antibiotic therapy.