Epidemiological Clues in Pathogenic Diagnosis of Culture-Negative Endocarditis Epidemiological Feature Common Microorganism(s) Injection drug use Staphylococcus aureus, including community-acquired methicillin/ oxacillin/nafcillin-resistant S aureus Coagulase-negative staphylococci -Hemolytic streptococci Fungi Aerobic Gram-negative bacilli, including Pseudomonas aeruginosa Polymicrobial Indwelling cardiovascular medical devices S aureus Coagulase-negative staphylococci Fungi Aerobic Gram-negative bacilli Corynebacterium spp Genitourinary disorders, infection, and manipulation, including pregnancy, delivery, and abortion Enterococcus species Group B streptococci (Streptococcus agalactiae) Listeria monocytogenes Aerobic Gram-negative bacilli Neisseria gonorrhoeae Chronic skin disorders, including recurrent infections S aureus -Hemolytic streptococci Poor dental health, dental procedures Viridans group streptococci Nutritionally variant streptococci Abiotrophia defectiva Granulicatella species Gemella species HACEK organisms Alcoholism, cirrhosis Bartonella species Aeromonas species Listeria species Streptococcus pneumoniae -Hemolytic streptococci Burn patients S aureus Aerobic Gram-negative bacilli, including P aeruginosa Fungi Diabetes mellitus S aureus -Hemolytic streptococci S pneumoniae Early ( 1 y) prosthetic valve placement Coagulase-negative staphylococci S aureus Aerobic Gram-negative bacilli Fungi Corynebacterium species Legionella species (Continued) Baltimore et al Infective Endocarditis in Childhood: 2015 Update 1509 circumstances, cardiological evaluation may suggest a need for early surgical therapy, performed even before steriliza- tion of blood. In a recent 15-year review of children treated for IE at the Texas Heart Institute in Houston, TX, early surgery was performed in 61% of patients, with most of these surgeries occurring within 7 days and half within 3 days of diagnosis.16 Several other studies have also shown that early surgery can be performed with low morbidity and mortality in childhood and improves the overall outcome Recent observational studies in adults have suggested that when adjusted for both selection and survi- vor biases, surgery in patients with left-sided IE, even when not considered urgent, may produce better outcomes and lower mortality than medical therapy alone.162,163 Although these data have not been replicated in specific pediatric- focused studies, the information does provide a reason- able framework for similar consideration in pediatric IE. 