An unusual bacterium, Aerococcus viridans, and four cases of infective endocarditis

Four cases are described of Aerococcus viridans endocarditis with favorable outcome, focusing on the clinical picture. Extracardiac findings (e.g. neurological, renal, musculoskeletal, intra-abdominal) in infective endocarditis (IE) have been recognized more frequently in recent years, and may delay the diagnosis and have a negative influence on the prognosis. Aerococcus viridans, a very rare microorganism causing invasive infections, has been associated with bacteremia, septic arthritis, and especially IE. As expected, the strains isolated were susceptible to penicillins, trimethoprim/sulfamethoxazole, and glycopeptides. Medical therapy was sufficient to cure IE in two patients, while two others required surgical intervention.