Abstract
A 35 years old female with known chronic left pelvo-ureteric junction (PUJ) obstruction presented with recurrent pyrexia and left loin pain and was treated for pyelonephritis. She had a history of severe aortic valve (AV) regurgitation. After five days of broad spectrum antibiotics and a percutaneous nephrostomy, her fevers persisted. Staphylococcus lugdunensis was isolated from her blood culture and she was diagnosed with mitral valve endocarditis following an echocardiogram. She was transferred to a tertiary cardiothoracic unit where she underwent a mitral and aortic mechanical valve repair. After 6 weeks of intravenous antibiotic treatment she was discharged without signs of infection but with poor cardiac function. S. lugdunensis is a virulent organism which is thought to be underdiagnosed and is associated with aggressive and destructive endocarditis. An awareness of the organism as well as prompt diagnosis and treatment with effective multi-disciplinary management is needed to avoid substantial morbidity in these patients. Whilst S. lugdunensis is known to cause invasive endocarditis, it has never been reported following pyelonephritis. The significance of this case is that despite receiving appropriate and timely treatment the patient was left with deteriorating cardiac function. This is an important reminder that this organism must be taken seriously when isolated in the context of infection. J Microbiol Infect Dis 2018; 8(1):37-40

Key words: Staphylococcus lugdunensis, endocarditis, pyelonephritis, heart valves, urinary tract