Aerococcus urinae endocarditis – A case report

Aerococcus urinae is a gram-positive coccus bacterium with a previously underestimated prevalence due to morphological similarities to other gram-positive cocci. Development of newer diagnostic technologies (such as matrix-assisted laser desorption ionization time-of-flight mass spectrometry MALDI-TOF) led to increased recognition of Aerococcus urinae as causative organism mainly for urinary tract infections. Its antibiotic susceptibility poses some challenges, with resistance to some drugs of choice for urinary tract infection. We report a case of a 69-year-old male with infective endocarditis of the mitral valve, who initially presented with fever and shoulder pain to the emergency department. The patient reported an episode of obstructive renal infection two weeks earlier, which was treated with trimethoprim-sulfamethoxazole. The unusual presentation with shoulder pain and a new heart murmur led to suspicion of endocarditis. Urine and blood cultures were positive for Aerococcus urinae, echocardiography revealed vegetations on the mitral valve with severe mitral insufficiency. After two weeks of antibiotic treatment, mitral valve replacement was performed, from which the patient recovered. Reports of Aerococcus urinae endocarditis are still limited in number. On the other side, Aerococcus urinae is an emerging bacterial uropathogen with greater relevance than previously believed. We review the case reports of Aerococcus urinae endocarditis and newest literature about its presentation, course, and clinical management.