Lactococcus lactis Causes Pulmonary Valve Endocarditis in a Patient with Complex Congenital Heart Disease

Lactococcus lactis (L. lactis) a gram-positive cocci used in the production of cheese and dairy products. Generally considered non-pathogenic in humans, rare cases have been reported describing L. lactis infections. Of these, infective endocarditis has been reported in a small number of cases. We describe here the case of a young patient with endocarditis caused by L. lactis. To our knowledge, this is the first case of endocarditis caused by L. lactis in a pulmonary valve with complex congenital heart disease. Similar to numerous cases in the literature that attest to the severity of this infection, our patient's course of development was fatal. Due to the limited information on the susceptibility of this bacterium, further research is required to develop conventional antibiotic therapy strategies to treat infective endocarditis caused by L. lactis.