Case of Swine Verrucous Endocarditis and Suppurative Encephalitis due to Streptococcus Dysgalactiae Subspecies Equisimilis

Abstract

A female growing-finishing pig, approximately 130 days old, exhibited astasia and subsequently died. A necropsy revealed systemic cyanosis, bilateral kidney infarction, verrucous endocarditis of the mitral and tricuspid valves, and punctate white lesions in the brain. Bacteriologically, Streptococcus dysgalactiae subspecies equisimilis was isolated from the liver, spleen, kidney, heart, heart verrucous lesions, lung, brain, and joints, and showed resistance to new quinolone drugs. A histopathological examination revealed valvular endocarditis, multiple microabscesses in the cerebrum, cerebellum, and brainstem, suppurative glomerulonephritis, and suppurative lymphadenitis due to gram-positive cocci. In addition, disseminated fibrous thrombosis, bacterial embolism, and suppurative vasculitis were observed. Immunohistochemically, the cocci were positive for an antibody against Streptococcus group C species. This case represents the first documentation of swine suppurative encephalitis and verrucous endocarditis due to S. equisimilis.