Pyometra Associated With Staphylococcus Pseudintermedius in Two Bitches.

Staphylococcus pseudintermedius is a commensal bacterium residing on the mucosae and skin surfaces of dogs. Under favorable conditions, the organism may cause serious infections, primarily involving the skin, but it is also isolated in eye and ear infections. This report describes pathologic findings of pyometra associated with S pseudintermedius in two bitches. One bitch was a 6-year-old Pomeranian bitch who died after three days of diarrhea, vomiting, and depression. During necropsy, the uterus of the bitch was diffusely enlarged and filled with 30 mL of thick, yellow, creamy pus. Histology revealed acute to subacute, diffuse, severe, purulent endometritis with intralesional Gram-positive round cocci revealed as S pseudintermedius. The cause of death was pyometra with subsequent septic shock. The other bitch was a 2-year-old West Highland White Terrier who underwent diagnostic laparotomy due to suppurative peritonitis of unknown cause. During the procedure, about 100 mL of yellow, opaque exudate from the abdominal cavity was removed. The distended uterine horns noted during the procedure were removed and submitted for histopathology which revealed necrosis of endometrium with the accumulation of pus and numerous, intralesional S pseudintermedius in the uterine lumen. Focally, uterine wall necrosis was evident, with a spread of bacteria and purulent inflammation into the adjacent mesometrium causing purulent peritonitis. Although S pseudintermedius presents a common cause of skin and mucosal infection, it should be considered a possible etiological agent of canine pyometra.