Lower respiratory tract infection due to Capnocytophaga cynodegmi in a cat with pulmonary carcinoma

A 10-year-old male castrated domestic shorthair cat was evaluated for coughing and lethargy. Thoracic radiographs revealed a soft tissue lung mass and diffuse peribronchial infiltrates. Bronchoscopy was performed and Capnocytophaga cynodegmi was cultured from bilateral bronchoalveolar lavage samples. Clinical signs and bacterial colonization resolved following treatment with enrofloxacin. A lung lobectomy was performed to remove the lung mass, which was diagnosed as pulmonary carcinoma. C cynodegmi is most frequently isolated from localized wound and corneal infections in humans. Specialized growth characteristics of C cynodegmi may result in low sensitivity for bacterial culture. To the authors' knowledge, this case represents the first report of C cynodegmi infection in a veterinary patient and only the second case in human or veterinary medicine where the organism has been isolated from a bronchoalveolar lavage sample. Based on this report, Capnocytophaga species should be considered as potential opportunistic pathogens.