## Epidemiology of Infective Endocarditis in India **Key Point:** Streptococcus viridans remains the most common cause of native valve endocarditis globally and in India, accounting for approximately 50–60% of cases. ### Organism-Specific Features | Organism | Prevalence (%) | Valve Preference | Risk Factor | Culture Characteristics | |----------|---|---|---|---| | **S. viridans** | 50–60 | Native (aortic > mitral) | Dental procedures, poor hygiene | Alpha-hemolytic, slow-growing | | S. aureus | 20–30 | Native or prosthetic | IV drug use, healthcare-associated | Beta-hemolytic, rapid growth | | E. faecalis | 5–10 | Prosthetic, mitral | Urinary instrumentation | Gamma-hemolytic, resistant to cephalosporins | | S. bovis | 5–10 | Native (aortic) | Colonic pathology (polyps, malignancy) | Alpha-hemolytic | **High-Yield:** In India, the high prevalence of poor oral hygiene, untreated dental disease, and rheumatic heart disease (RHD) as an underlying substrate makes S. viridans the leading pathogen. It is an alpha-hemolytic streptococcus that colonizes the oral cavity and enters the bloodstream via dental procedures or poor dentition. ### Clinical Correlation **Clinical Pearl:** S. viridans endocarditis typically presents with an insidious course (weeks to months) with constitutional symptoms, new cardiac murmurs, and septic emboli. Blood cultures are positive in >95% of cases if antibiotics have not been given. **Mnemonic:** **VIRIDANS = Viridans is the most common cause (Remember: Viridans = Valve infection, Indolent course, Rheumatic heart disease substrate, Dental source)** ## Why S. viridans Dominates in India 1. High burden of untreated dental caries and periodontal disease 2. Frequent dental procedures without antibiotic prophylaxis 3. Large population with underlying RHD (predisposing factor) 4. S. viridans is part of normal oral flora and readily enters bloodstream through breaks in mucosa
Sign up free to access AI-powered MCQ practice with detailed explanations and adaptive learning.