Isolation of Neisseria dumasiana from a deep bite wound infection in a dog

Background Neisseria spp. is a common inhabitant of the oral flora of cats and dogs; it is a potential cause of cutaneous infections in people secondary to animal bites. Neisseria dumasiana is a new species identified in the oral cavity of dogs. It has not been linked to cutaneous infections in people. Objective To describe the clinical and microbiological features of Neisseria dumasiana isolated from the skin of a dog. Animal A 3-year-old male neutered mixed breed dog from Florida, USA. Methods and materials The dog had no travel history within or outside the United States; the dog was presented with draining tracts on the dorsum. Five months before the initial examination the dog was involved in a fight with another dog. Results An aerobic bacterial culture was performed and isolated multiple small, grey, moist, circular, convex and nonhaemolytic colonies. A Gram stain showed Gram-negative coccobacilli present in pairs. The bacteria were oxidase- and catalase-positive and negative for indole and fermentation of fructose, xylose, sucrose, mannitol and sorbitol. Polymerase chain reaction, using 16S rDNA sequencing, was positive for Neisseria dumasiana. Clinical and microbiological resolution occurred within three months of treatment. Conclusions and clinical importance To the best of the authors' knowledge, this is the first report of a deep cutaneous dermatitis associated with Neisseria dumasiana in a dog. This case should stimulate veterinary clinicians and microbiologists to consider Neisseria spp. among the differential diagnoses of nonhealing wounds in dogs, particularly those associated with bite wounds.