What causes subacute bacterial endocarditis?

Subacute endocarditis is also known as subacute infective endocarditis. It is commonly caused by organisms such as viridans streptococci. The mitral and aortic valves are most frequently involved. What, then, causes subacute bacterial endocarditis?

Causes of Subacute Bacterial Endocarditis

The etiology of subacute bacterial endocarditis is bacterial infection. Acute infective endocarditis is typically caused by pyogenic bacteria invading the endocardium, often resulting from highly virulent pathogens—Staphylococcus aureus, for instance, accounts for over 50% of cases. Prior to the clinical use of antibiotics, non-hemolytic streptococci—predominantly viridans streptococci—caused approximately 80% of subacute endocarditis cases. Drug-related factors: The widespread use of broad-spectrum antibiotics has markedly altered the spectrum of causative pathogens. Indeed, all known pathogenic microorganisms can cause this disease, and the same pathogen may produce either an acute or a subacute clinical course.

Fungal infection: Fungi are more commonly observed in patients who have undergone cardiac surgery or who inject drugs intravenously. Prolonged administration of antibiotics, immunosuppressants, or corticosteroids—as well as intravenous infusion of high-nutrient solutions via central venous catheters—increases both the likelihood and risk of fungal infection. Common fungal pathogens include Candida, Aspergillus, and Histoplasma.

The onset is insidious, with symptoms including fever (often irregular), fatigue, diaphoresis, weight loss, and arthralgia. In later stages, organ embolism may occur. We hope this information proves helpful to you!