Pneumonia and meningitis in a Beagle Dog caused by Actinomyces bowdenii

A 5-year-old female Beagle Dog was euthanized following ten days of inappetence, lethargy, and pain in the left cervical region that was not responsive to steroids or antibiotics. At necropsy, there were multiple soft dark red to tan nodules throughout all lung lobes, abundant purulent subdural exudate over the right temporal lobe of the brain, and minimally enlarged submandibular and tracheobronchial lymph nodes. Impression smear of the subdural pus and histologic section of the lung and meninges demonstrated small aggregates of rod-shaped to filamentous bacteria often surrounded by Splendori-Hoeppli material. Aerobic culture of the subdural exudate yielded pure growth of Actinomyces bowdenii. To our knowledge, this is the first report of central nervous disease or pneumonia associated with Actinomyces bowdenii.