Microbiological characterization and antimicrobial susceptibility patterns of isolates in cases of infective endocarditis: A study from North India

Background: Infective endocarditis (IE) remains a critical clinical challenge, particularly in developing countries, due to high morbidity, and rising antimicrobial resistance.Aims & Objectives: To evaluate the microbial profile and antimicrobial susceptibility patterns in patients with infective endocarditis.Materials and Methods: A prospective observational study was conducted on 181 patients for suspected infective endocarditis. Blood cultures were processed with extended incubation and isolates were identified by standard methods, and followed required guidelines. Biofilm production was also screened.Results: Of 181 patients, 39.8% (72) met criteria for definite infective endocarditis, while 60.2% (109) were classified as possible cases. Blood cultures were positive in 82 cases (45.3%). Gram-positive organisms predominated (65%), with Staphylococcus aureus (30 isolates) and coagulase-negative staphylococci (18) most frequent, followed by Enterococcus spp. (5). Anaerobes were recovered in 6 cases (10%), mainly Bacteroides and Peptostreptococcus. Antimicrobial resistance patterns revealed high rates of methicillin resistance among staphylococcal isolates. Biofilm formation was observed in 85% of isolates. Most patients were young adults (18–30 years, 66%), with a predominance of intravenous drug use (IVDU). Culture-positive patients experienced more complications, while culture-negative patients had better recovery.Conclusion: Infective endocarditis in North India remains largely a disease of young rural adults, often linked to IVDU and tricuspid valve involvement. Staphylococcus species were the most common pathogens. The study underscores the importance of early microbiological diagnosis and tailored antimicrobial therapy in managing infective endocarditis which can guide empirical treatment strategies and future diagnostic protocols.