Box 2.

Modified Duke criteria for endocarditis. Definite infective endocarditis = two major, or one major and three minor, or five minor; possible infective endocarditis = one major and one minor, or three minor.

Major criteria:

  • blood cultures:

    • typical microorganisms consistent with IE from two separate blood cultures:

      • viridans group streptococci, Streptococcus bovis group, HACEK group, Staphylococcus aureus; or

      • community-acquired enterococci with absence of a primary focus; or

    • microorganisms consistent with IE from persistently positive blood cultures:

      • ≥2 positive blood cultures drawn >12 hours apart; or

      • all of three or a majority of ≥4 separate blood cultures (first and last samples ≥1 hour apart); or

      • single positive blood culture for Coxiella burnetii or phase IgG antibody titre >1:800

    • imaging:

      • echocardiogram positive for IE:

        • vegetation

        • abscess, pseudoaneurysm or intracardiac fistula

        • valvular perforation or aneurysm

        • new partial dehiscence of prosthetic valve

      • abnormal activity around the site of a prosthetic valve detected by PET/CT assuming >3 months after surgery or radiolabelled leucocyte-SPECT/CT

      • definite paravalvular lesions by cardiac CT.

Minor criteria:

  • predisposing heart condition or intravenous drug use

  • fever >38°C

  • vascular phenomena (including those detected by imaging alone): arterial emboli, splenic infarction, mycotic aneurysms, intracranial haemorrhage and Janeway lesions

  • immunological phenomena: glomerulonephritis, Osler's nodes, Roth's spots and rheumatoid factor

  • microbiological evidence: positive blood cultures not meeting major criteria above or serological evidence of infection with organism consistent with IE.

  • CT = computed tomography; HACEK = Haemophilus spp, Aggregatibacter spp, Cardiobacterium hominis, Eikenella corrodens, Kingella spp; IE = infective endocarditis; IgG = immunoglobulin G; PET = positon emission tomography; SPECT = single-photon emission computed tomography.