A Case of Pacemaker Endocarditis Caused by Aerococcus urinae

Aerococcus urinae, a rare cause of aortic root abscess: a case report

BACKGROUND

Aerococcus urinae is a bacterium of emerging clinical interest that most commonly causes urinary tract infections (UTI) but can also result in invasive infections. It is a catalase-negative, alpha-haemolytic gram-positive coccus that grows in clusters or tetrads and usually causes urinary tract infections. While rare, infective endocarditis must be considered when A. urinae is isolated in blood culture. The mortality rate of A. urinae infective endocarditis is similar to overall endocarditis mortality. We report a rare case of aortic root abscess caused by A. urinae.

CASE PRESENTATION

An 82-year-old Caucasian man presented to hospital with behavioural change and severe malnutrition and was managed for psychotic depression. On day 34 of his inpatient stay, a febrile episode prompted blood cultures, which grew Aerococcus. urinae. Investigations revealed a bicuspid aortic valve, aortic valve endocarditis and aortic root abscess. He also had prostatomegaly. He underwent aortic valve replacement, received 6 weeks of intravenous ceftriaxone and recovered.

CONCLUSION

Infective endocarditis should be considered in patients with persistent Aerococcus urinae bacteraemia. Accurate identification with mass spectrometry is recommended to avoid misidentification as staphylococcus, streptococcus or enterococcus, which is a possibility with conventional laboratory methods.

Mitral Valve Endocarditis with Perforation from a Urinary Source: An Unusual Case and Literature Review

Aerococcus urinae (AU) is a rare pathogen, identified as gram-positive, catalase-negative coccus that grows in pairs and clusters which has been reported to mainly cause urinary tract infections (UTI), especially in elderly males. Treatment for this microorganism is usually with beta-lactams although cultures with antibiotic susceptibility testing are imperative. We present a case of AU endocarditis initially treated with IV antibiotics; nevertheless, the patient required emergent mitral valve replacement due to severe mitral insufficiency and perforation. We also present an analysis with high-yield points summarizing epidemiology, risk factors, microbiology, clinical features, diagnostic workup, and management of AU in general and AU endocarditis. Finally, we post a literature review of relevant cases and the impact of different variables associated with it.