The more virulent bacteria cause the acute form that can lead to serious destruction, as shown here in the aortic valve. Irregular reddish tan vegetations overlie valve cusps that are being destroyed.
Acute bacterial endocarditis
The disease is caused by Staphylococcus aureus with extensive cuspal destruction and ring abscess (arrow).
Acute endocarditis of congenitally bicuspid aortic valve
Bacterial endocarditis: myocardial microabscess
The center consists of blue bacterial colonies and is surrounded by acute inflammatory cells.A, Nearly complete row of thrombotic vegetations along the line of closure of the mitral valve leaflets (arrows). B, Photomicrograph of nonbacterial thrombotic endocarditis, showing bland thrombus, with virtually no inflammation in the valve cusp (c) or the thrombotic deposit (t). The thrombus is only loosely attached to the cusp (arrow).
Nonbacterial thrombotic endocarditis