The aortic valve demonstrates a large, irregular, reddish tan vegetation.Virulent organisms, such as Staphylococcus aure毒力强的细菌，如金黄色葡萄球菌，引起“性细菌性心内膜炎，而一些毒力较弱的细菌，如草绿色链球菌，则引起亚急性细菌性心内膜炎。