Cutaneous Serratia marcescens infection in two dogs

We describe two canine cases of cutaneous infection caused by Serratia marcescens . A 2‐year‐old castrated male mixed dog (Case 1) presented with multiple ulcerations on the dorsal trunk, which were observed 4 days after shampooing. A 4‐year‐old male wolf shepherd mix dog (Case 2) presented with ulceration and purulent discharge on the nasal bridge. Cytological examination of both cases revealed pyogranulomatous inflammatory cells with rod‐like infectious agents identified as S. marcescens in aerobic bacterial culture. Both patients were treated with oral antibiotics and topical chlorhexidine. Case 1 received enrofloxacin 10 mg/kg once daily for 1 week, followed by trimethoprim/sulfamethoxazole 15 mg/kg twice daily for 3 weeks. Case 2 received doxycycline 10 mg/kg twice daily for 4 weeks. No skin lesions were detected 2 weeks after the initial administration. The antibiotics were discontinued after a total 4 weeks of administration, and the skin lesions did not reappear.