Spontaneous Infection Caused by Streptococcus agalactiae in KK-A Mice

During 2006 through 2012, spontaneous group B Streptococcus infections were reported in 22 female KK-Ay mice, an animal model of type 2 diabetes. The affected mice were 5 to 27 wk old, and the cases involved various body sites, including cases of submandibular, caudal, and lumbar abscesses (n =18) or led to torticollis (n = 2), hydrocephalus (n = 1), or moribund clinical signs (n = 1). At necropsy, the mouse with hydrocephalus also demonstrated retained exudate in the uterus, and the moribund mouse showed renal inflammation. Streptococcus agalactiae was isolated in pure culture from all except 2 cases: the facial abscess also yielded Klebsiella pneumoniae, and the uterine exudate was coinfected with Staphylococcus aureus. In addition, S. agalactiae was isolated from the oral cavity and feces of normal KK-Ay mice. S. agalactiae potentially can cause a clinically significant spontaneous infection in a mouse model of diabetes.