Streptococci are the leading cause of infective endocarditis (IE), accounting for 30%-65% of cases. Among these, streptococci viridans (alpha-hemolytic streptococci), commonly found in the mouth and gut, are the most frequent cause of community-acquired native valve endocarditis (NVE). Staphylococci contribute to 30%-40% of IE cases, with coagulase-positive Staphylococcus aureus being the primary culprit in IE linked to intravenous drug abuse and nonvalvular cardiovascular device infections. Recent studies indicate that S. aureus is now the most common cause of IE, while the prevalence of viridans streptococci has declined. Other less common IE-causing agents include the HACEK group (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella), Pseudomonas aeruginosa, Corynebacterium, Bacteroides fragilis, and fungi.