A rare case of Aerococcus urinae native valve endocarditis

Background Aerococcus urinae, was initially considered a commensal of the urinary tract, but there is now increasing evidence for its involvement in urinary tract and systemic infections. A. urinae endocarditis has a high mortality rate and occurs mainly in patients with underlying conditions or presence of extraneous material. Case presentation This report handles the case of a 65 year old male with cardiac antecedents, who was admitted to the cardiology department after a syncope of unknown origin and diagnosed with severe mixed aortic valve disease and mitral valve sclerosis through the means of a transesophageal echocardiography (TEE). During hospitalisation, the patient progressively deteriorated with the development of shortness of breath and an inflammatory syndrome. Urinary laboratory analysis showed an A. urinae infection and blood cultures depicted A. urinae growth. Treatment with piperacillin/tazobactam was started empirically. Repeated TEE showed evidence for endocarditis with vegetation and perforation of the mitral valve that required an emergency surgery with mitral valve repair. After surgery, gentamicin and penicillin G were administered for 48 hours, followed by combined ceftriaxone/penicillin G treatment for 6 weeks. At first, flucloxacillin was also associated as the culture of the valve was negative. Finally, 16S rRNA polymerase chain reaction (PCR) on the valve tissue, confirmed the A. urinae endocarditis. Conclusion A. urinae is an underestimated cause of serious infections such as endocarditis. Urinary tract infections mainly in older men can be an entry point for this type of invasive infection.