A 9-month-old infant presented with fever, dyspnoea, and a murmur. Echocardiography showed a mitral vegetation with significant regurgitation. Mitral valve plasty was performed on day 6, and was polymerase chain reaction positive for Kingella kingae. The cardiac outcome was favourable. This case illustrates a subtle presentation of K. kingae mitral valve infective endocarditis in a normal-cardaic infant, treated with early surgery, and the agent belonged to the HACEK (Haemophilus spp Actinobacillus actinomycetemcomitans, Capnocytophaga spp, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae) group.
