The common causative organism is Staphylococcus aureus. Abscesses can originate from acute pyogenic infections or from the transfer of pathogenic bacteria from a distant primary source of infection through the bloodstream or lymphatics. It is often due to necrosis and lysis of the inflamed tissue in response to toxins or enzymes produced by the bacteria, resulting in the formation of a pus cavity, in which exudate, necrotic tissue, pus cells, and bacteria combine to form pus. The formation of a reticular scaffolding by fibrin in the pus is what confines the lesion to the local area, and there is congestion and edema and leukocyte infiltration around the pus cavity. Eventually the wall of the abscess cavity is dominated by granulation tissue proliferation. Abscesses can present with different clinical manifestations depending on their location. Acute bacterial endocarditis is often caused by bacteria with strong pathogenicity, with Staphylococcus aureus, hemolytic streptococcus, pneumococcus, influenza bacillus, Proteus mirabilis and Escherichia coli being the most common. These bacteria are highly virulent, have a rapid onset, are severe, and are often secondary to infections elsewhere as part of a systemic infection, such as meningitis, pneumonia, and thrombophlebitis, sometimes accompanied by metastatic septic foci in other organs. It usually occurs in the normal heart. Acute bacterial endocarditis with staphylococcal infection may be complicated by lung abscesses, brain abscesses and other migrating abscesses, presenting with coughing, dyspnea, convulsions, and hemiparesis.