Definition of Infective Endocarditis (IE): Modified Duke Criteria

Definite Infective Endocarditis 
 Pathological Criteria
• Microorganisms demonstrated by results of cultures or histologic examination of a vegetation, a vegetation that has embolized, or an intracardiac abscess specimen; or
• Pathologic lesions; vegetation, or intracardiac abscess confirmed by results of histologic examination showing active endocarditis
Clinical Criteria
• 2 major criteria, or
• 1 major criterion and 3 minor criteria, or
• 5 minor criteria
Possible Infective Endocarditis
• 1 major criterion and 1 minor criterion or 3 minor criteria
Rejected Diagnosis of Infective Endocarditis
• Firm alternate diagnosis explaining evidence of suspected IE, or
• Resolution of IE syndrome with antibiotic therapy for ≤4 days, or
• No evidence of IE at surgery or autopsy, on antibiotic therapy for ≤4 days, or
• Does not meet criteria for possible IE
Definition of Terms Used in the Modified Duke Criteria for Diagnosis of Infective Endocarditis
Major Criteria
• Blood culture findings positive for IE
Typical microorganisms consistent with IE from two separate blood cultures:
• Viridans streptococci, Streptococcus gallolyticus (formerly known as S. bovis ), Staphylococcus aureus, HACEK group, or
• Community-acquired enterococci, in the absence of a primary focus, or
Microorganisms consistent with IE from persistently positive blood culture findings, defined as:
• ≥2 positive culture findings of blood samples drawn >12 hours apart, or
• 3 or most of ≥4 separate culture findings of blood (with first and last sample drawn ≥1 hour apart)
• Single positive blood culture for Coxiella burnetii or anti–phase I IgG titer ≥1 : 800
• Evidence of endocardial involvement
Echocardiographic findings positive for IE (TEE recommended in patients with prosthetic valves, rated at least possible IE by clinical criteria or complicated IE [paravalvular abscess]; TTE as first test in other patients), defined as follows:
• Oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative anatomic explanation, or
• Abscess, or
• New partial dehiscence of prosthetic valve
New valvular regurgitation; worsening or changing of preexisting murmur not sufficient
Minor Criteria
• Predisposition, predisposing heart condition, or intravenous drug use
• Fever—temperature >38°C
• Vascular phenomena, major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, and Janeway lesions
• Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots, and rheumatoid factor
• Microbiologic evidence: positive blood culture finding but does not meet a major criterion as noted above (excludes single positive culture findings for coagulase-negative staphylococci and organisms that do not cause endocarditis) or serologic evidence of active infection with organism consistent with IE

Modified from Li JS, Sexton DJ, Mick N, et al. Proposed modifications to the Duke criteria for the diagnosis of infective endocarditis. Clin Infect Dis 2000;30:633.