Decision support only — not a substitute for the 2023 ESC guideline, eTG, or your Endocarditis Team. Two reflexes that change outcomes: take blood cultures before antibiotics, and involve the Endocarditis Team early at a valve centre. Antibiotic choice is organism- and susceptibility-driven — confirm every regimen with ID/microbiology. Verify all doses.
1 Diagnose it — the workup
Suspecthave a low threshold
Fever + a reason.
Predisposing valve/prosthesis/IVDU, new regurgitant murmur, embolic or immune phenomena — and any S. aureus bacteraemia should prompt the question.
Culturebefore antibiotics
The single highest-yield step.
≥3 sets of blood cultures from separate venepunctures before starting antibiotics (unless septic shock). Culture-negative IE is hard to treat — don't create it.
Imageecho first, then more
Looking for vegetation, abscess, dehiscence.
TTE → TOE (more sensitive; essential for prosthetic valves & abscess). 18F-FDG PET/CT and cardiac CT are now major criteria — valuable in prosthetic-valve/CIED IE.
Classify & conveneteam it
Definite / possible / rejected.
Apply the 2023 Duke-ISCVID criteria Duke-ISCVID; manage anything complex through the Endocarditis Team at a Heart Valve Centre.
2023 Duke-ISCVID additions: PET/CT & cardiac CT imaging, expanded molecular microbiology (PCR, metagenomics, Bartonella serology), intra-operative inspection as a new major criterion, and relaxed blood-culture timing. Still: a normal TTE doesn't exclude IE — go to TOE when suspicion persists.
2 When to operate — three indications
Heart failurecommonest & most urgent
Valve dysfunction → acute regurgitation, pulmonary oedema, or shock.
Emergency/urgent surgery — refractory pulmonary oedema or cardiogenic shock from acute regurgitation is an emergency (<24h).
Uncontrolled infectioncan't sterilise it
Persistent infection despite appropriate antibiotics.
Urgent surgery for perivalvular abscess/extension, fistula, new heart block, persistent bacteraemia, or fungal/multidrug-resistant organisms.
Embolism preventionlarge vegetations
High embolic risk.
Early surgery for vegetation ≥10 mm with an embolic event despite antibiotics, or large vegetations with another indication Kang.
Around half of IE patients ultimately need surgery — involve cardiac surgery early, don't wait for deterioration. Timing is emergency (<24h), urgent (within days), or elective; the Endocarditis Team weighs operative risk, stroke, and organism. Post-embolic stroke usually delays surgery only briefly unless there's haemorrhage.
3 Antibiotics — principles, not a recipe
Empirical & directed
- NativeCover staph + strep + enterococcus — e.g. benzylpenicillin + flucloxacillin 2 g IV q4–6h + gentamicin (or vancomycin-based if MRSA risk/allergy).
- ProstheticVancomycin + gentamicin + rifampicin (add rifampicin once bacteraemia clears).
- MSSAFlucloxacillin 4–6 weeks. MRSA → vancomycin or daptomycin.
- Strep/Enteroc.Penicillin-S strep → benzylpenicillin or ceftriaxone. Enterococcus → amoxicillin + ceftriaxone (or gentamicin).
Duration & getting them home
- DurationTypically 4–6 weeks IV bactericidal therapy (shorter for some uncomplicated native strep).
- Oral step-downAfter initial IV stabilisation, stable left-sided IE can switch to oral antibiotics to finish the course POET.
- OPATOutpatient parenteral therapy for stable, low-risk patients via the IE/ID service.
- VerifyRegimens are organism/susceptibility-driven — always confirm with ID & eTG.
4 Prophylaxis & don't-miss
Prophylaxis — narrow & specific
- WhoHighest-risk only: prosthetic valve (incl. TAVI)/prosthetic repair material, previous IE, certain congenital heart disease, and (2023) ventricular assist devices.
- WhenOnly for dental procedures involving gingival/periapical manipulation or oral-mucosa perforation.
- WhatAmoxicillin 2 g PO 30–60 min before. Clindamycin is no longer recommended for allergy.
- Bigger leverGood oral hygiene & regular dental care matter more than antibiotics.
Don't miss
- S. gallolyticusS. gallolyticus (bovis) IE → colonoscopy (colorectal neoplasia); enterococcal → look for a GI/GU source.
- S. aureusAny S. aureus bacteraemia → echo, hunt for IE, remove infected lines/devices.
- Right-sidedIVDU → tricuspid IE, septic pulmonary emboli; often managed medically.
- SpreadLook for metastatic infection — cerebral, splenic, vertebral (discitis), mycotic aneurysm.
Sources.
2023 ESC Guidelines for the management of endocarditis (Eur Heart J 2023 — Duke-ISCVID criteria with PET/CT & cardiac CT and intra-operative inspection as major criteria; Endocarditis Team & Heart Valve Centres; blood cultures before antibiotics; TTE→TOE; surgery for heart failure / uncontrolled infection / embolism prevention; outpatient parenteral & oral step-down therapy; restricted antibiotic prophylaxis). 2023 Duke-ISCVID criteria (Fowler et al). eTG (Antibiotic) for Australian regimens.
Key trials: POET (partial oral antibiotic therapy non-inferior in stable left-sided IE, sustained at 5 years); Kang et al (early surgery reduces embolic events).
Caveats: antibiotic regimens are organism-, susceptibility-, and valve-type-specific and ID-led — the doses here are orientation, not prescriptions; confirm with eTG and microbiology. Surgical timing is an Endocarditis Team decision. Prophylaxis guidance differs between societies (ESC vs NICE vs AHA) — the trend is toward narrower use plus dental hygiene. Verify all doses. Companion to the cardiac & valvular sheets.