Major Criteria

1. Positive blood culture

• Typical microorganism for infective endocarditis from two separate blood cultures
  • Viridans streptococci, Streptococcus bovis, HACEK group, Staphylococcus aureus, or
  • Community-acquired enterococci in the absence of a primary focus, or

• Persistently positive blood culture, defined as recovery of a microorganism consistent with infective endocarditis from:
  • Blood cultures drawn >12 h apart; or
  • All of three or a majority of four or more separate blood cultures, with first and last drawn at least 1 h apart

• Single positive blood culture for Coxiella burnetii or phase I IgG antibody titer of >1:800

2. Evidence of endocardial involvement

• Positive echocardiogram^a
  • Oscillating intracardiac mass on valve or supporting structures or in the path of regurgitant jets or in implanted material, in the absence of an alternative anatomic explanation, or
  • Abscess, or
  • New partial dehiscence of prosthetic valve, or

• New valvular regurgitation (increase or change in preexisting murmur not sufficient)

Minor Criteria

1. Predisposition: predisposing heart condition or injection drug use
2. Fever ≥38.0°C (≥100.4°F)
3. Vascular phenomena: major arterial emboli, septic pulmonary infarcts, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhages, Janeway lesions
4. Immunologic phenomena: glomerulonephritis, Osler’s nodes, Roth’s spots, rheumatoid factor
5. Microbiologic evidence: positive blood culture but not meeting major criterion as noted previously^b or serologic evidence of active infection with organism consistent with infective endocarditis

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^aTransesophageal echocardiography is recommended for assessing possible prosthetic valve endocarditis or complicated endocarditis.
^bExcluding single positive cultures for coagulase-negative staphylococci and diphtheroids, which are common culture contaminants, and organisms that do not cause endocarditis frequently, such as gram-negative bacilli.
Note: HACEK, Haemophilus spp., Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, Kingella kingae.
Source: Adapted from JS Li et al: Clin Infect Dis 30:633, 2000, with permission from the University of Chicago Press.

Chapter:
Infective Endocarditis