Fulminant prosthetic valve endocarditis after transcatheter aortic valve implantation caused by non-typeable Streptococcus agalactiae with central nervous system involvement: a case report

Infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) is an uncommon but life-threatening complication, often associated with diagnostic challenges. Streptococcus agalactiae (GBS) is increasingly recognized as a cause of invasive infection in older adults and may exhibit a rapidly progressive clinical course with central nervous system involvement.

An 85-year-old woman with a history of TAVI presented with acute-onset fever and was diagnosed with GBS bacteraemia. Initial transthoracic echocardiography (TTE) showed no vegetations. On hospital Day 3, she developed delirium and neck stiffness suggestive of meningitis, with intracranial haemorrhage on computed tomography. Repeat TTE demonstrated newly developed vegetations on the prosthetic aortic valve and anterior mitral leaflet, with worsening mitral regurgitation, leading to a diagnosis of IE. The causative organism was identified as non-typeable GBS. Despite intensive antimicrobial therapy, her condition rapidly deteriorated with shock and multiorgan failure, and she died on hospital Day 7.

This case highlights the fulminant nature of invasive GBS infection in elderly patients, particularly when associated with prosthetic valve IE after TAVI. Notably, this case was characterized by multivalvular involvement and possible central nervous system involvement. These features may reflect a severe disease phenotype driven by highly invasive bacteraemia and structural vulnerability related to the transcatheter valve system. Initial echocardiographic findings may be inconclusive, necessitating repeated evaluation. In addition to embolic complications, central nervous system involvement should be considered in cases of neurological deterioration. Early recognition is critical; however, prognosis remains poor once severe complications develop.