Skip to main content

Health condition · Clinically reviewed

Infective endocarditis, Duke criteria, IV antibiotics and when surgery is needed.

A life-threatening infection of the heart valves. Diagnosis is urgent, treatment is long, and outcomes are shaped by a specialist endocarditis team.

Jump to treatment
A radiographer guides a patient onto the bed of an advanced 3 Tesla MRI scanner in a London imaging suite

Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against ESC 2015, BSAC, AHA and NICE, with the sources listed at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including endocarditis-team management, Duke criteria and specialist-centre surgery.

Key facts

Endocarditis at a glance.

The essentials, in plain English - what it is, why it matters and how it is treated in the UK today.

  • What it is

    Infection of the endocardial surface of the heart, usually a valve. Life-threatening and always managed as a specialist condition.

  • How common

    UK incidence around 5 to 7 per 100,000 per year, and rising with an ageing population, more prosthetic valves and injecting drug use.

  • Main types

    Native valve, prosthetic valve, cardiac-device related, right-sided in IV drug users, culture-negative, non-bacterial and fungal.

  • Diagnosis

    Duke criteria plus blood cultures and echocardiography (TTE first, then TOE if needed) - all done urgently.

  • Backbone of care

    Four to six weeks of targeted IV antibiotics under specialist microbiology, with early surgery for the right patients.

  • Where it is done

    Managed by a specialist endocarditis team - often at a tertiary UK centre with cardiac surgery on site.

Why this guide matters

A team decision, not a solo call.

Endocarditis outcomes hinge on getting three things right - early cultures, the right echo and a specialist team steering the plan.

  • Blood cultures come first

    Three sets from separate sites at least an hour apart, ideally before antibiotics. This is the single biggest determinant of a clean microbiological diagnosis.

  • Echo does the heavy lifting

    TTE first, then TOE for prosthetic valves and unclear cases. Duke criteria pull it together with clinical features and cultures.

  • Specialist team, specialist centre

    A dedicated endocarditis team - cardiology, cardiac surgery, infection and microbiology - improves outcomes and defines who needs surgery.

How the diagnosis is made

From first fever to a confirmed plan.

The steps a UK cardiology and infection team will normally follow, in order - so you know what to expect and why.

  1. 01

    Assessing

    Clinical suspicion

    Unexplained fever with a new murmur, embolic events or a valve prosthesis is enough to start the workup - do not wait for peripheral signs.

  2. 02

    Assessing

    Three sets of blood cultures

    Taken at least one hour apart from separate sites, ideally before any antibiotics. This is the single most important step.

  3. 03

    Assessing

    Baseline bloods and urine

    FBC, CRP, ESR, U and Es, rheumatoid factor, complement and immunoglobulins, plus urine dip for haematuria and proteinuria.

  4. 04

    Confirming

    Transthoracic echo (TTE)

    First-line imaging to look for vegetations, abscess and valve destruction. A normal TTE does not rule endocarditis out.

  5. 05

    Confirming

    Transoesophageal echo (TOE)

    Higher sensitivity and specificity - used for prosthetic valves, inconclusive TTE and suspected complications, in a specialist centre.

  6. 06

    Confirming

    Duke criteria and MDT review

    Modified Duke criteria plus a specialist endocarditis team decision on antibiotics, imaging and the case for surgery.

  7. 07

    Refining

    Advanced imaging if needed

    18F-FDG PET/CT for prosthetic-valve, device-related or culture-negative cases. Serology for Coxiella, Bartonella and Brucella when cultures stay negative.

Typical timeline: cultures within hours, echo within a day, a full plan within days.

Symptoms

What endocarditis actually looks like.

Fever is the constant. Around it sit murmurs, heart failure, embolic events and the classic peripheral signs - and the features that mean it is time to escalate.

  • Fever, chills and malaise

    The most common presenting feature - often with night sweats, weight loss and feeling generally very unwell over days to weeks.

  • New or changing murmur

    A new regurgitant murmur, or a change in an existing one, points at valve damage and needs urgent assessment.

  • Heart failure

    Breathlessness, swollen ankles and fatigue from acute valve regurgitation - a key trigger for early surgery.

  • Embolic events

    Stroke, splenic or kidney infarct and mycotic aneurysm from vegetation fragments travelling in the bloodstream.

  • Septic pulmonary emboli

    Right-sided endocarditis, typically in IV drug users, sends infected clots to the lungs - cough, chest pain and breathlessness.

  • Peripheral signs

    Osler nodes, Janeway lesions, splinter haemorrhages, Roth spots and petechiae. Uncommon now, but classic when they appear.

  • Immune-mediated features

    Glomerulonephritis, arthralgia and vasculitic rashes reflect immune complexes rather than direct infection.

  • Red flag - prosthesis plus fever

    Any fever in someone with a prosthetic valve, pacemaker or ICD is endocarditis until proven otherwise.

Treatment

How endocarditis is treated in the UK.

Empirical antibiotics start straight after cultures, then targeted IV therapy for four to six weeks - with early surgery when the situation demands it.

  • Empirical native-valve antibiotics

    Amoxicillin, flucloxacillin and gentamicin while cultures are awaited - with MRSA cover added if there is any suspicion.

  • Empirical prosthetic-valve cover

    Vancomycin, gentamicin and rifampicin for early prosthetic valve infection, then narrowed once cultures return.

  • Targeted IV antibiotics

    Four to six weeks tailored to organism and susceptibility - flucloxacillin for MSSA, vancomycin or daptomycin for MRSA, penicillin for streptococci, ceftriaxone for HACEK.

  • Enterococcal regimens

    Amoxicillin plus gentamicin, or amoxicillin plus ceftriaxone in selected cases - guided by specialist microbiology.

  • Antifungal therapy

    Echinocandin or amphotericin for Candida and Aspergillus, followed by long-term suppression - almost always alongside surgery.

  • OPAT

    Outpatient parenteral antibiotic therapy for stable, carefully selected patients - after an initial inpatient stabilisation phase.

  • Valve surgery

    For heart failure, uncontrolled infection or high embolic risk - repair or replacement, done at a tertiary centre.

  • Device extraction

    Complete removal of a pacemaker or ICD system in lead-related infection, with reimplantation delayed until infection is controlled.

What this guide is based on

The sources behind every claim on this page.

UK and international specialist society standards, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your cardiology and infection team knows your history, echo findings and cultures, and can tell you which parts apply to you. If you are unwell, seek urgent care.

  • European Society of Cardiology (ESC). 2015 guidelines for the management of infective endocarditis.

  • British Society for Antimicrobial Chemotherapy (BSAC). Guidelines for the diagnosis and antibiotic treatment of endocarditis in adults.

  • American Heart Association (AHA). Infective endocarditis in adults - scientific statement.

  • NICE CG64. Prophylaxis against infective endocarditis.

Red flags

When endocarditis needs urgent attention.

Endocarditis is always urgent. These are the situations where waiting is not safe - and where escalation should happen the same day.

  • Fever with a prosthetic valve

    Any unexplained fever after valve replacement is endocarditis until proven otherwise - urgent hospital assessment.

  • Fever with a pacemaker or ICD

    Device-related infection can be indolent. Persistent fever or malaise needs cardiology and infection team review.

  • New murmur and fever

    A new regurgitant murmur with fever is a classic red-flag combination and warrants same-day admission.

  • Stroke or systemic embolism with fever

    Embolic event plus fever in anyone with a valve lesion or IV drug use points strongly at endocarditis.

  • IV drug use with fever

    Right-sided endocarditis and septic pulmonary emboli are common - low threshold for cultures and echo.

  • Streptococcus gallolyticus bacteraemia

    Strongly linked to colonic malignancy - triggers colonoscopy as well as endocarditis workup.

  • Heart failure on the ward

    New or worsening heart failure in suspected endocarditis often needs urgent surgery, not just more antibiotics.

  • Persistent fever on treatment

    Ongoing fever after five to seven days of targeted antibiotics suggests abscess or uncontrolled infection - reimage and reconsider surgery.

  • Neurological change

    New confusion, weakness or headache can mean stroke or mycotic aneurysm - urgent neuroimaging and specialist review.

Living with it

A serious illness, with a long recovery.

Four things that make the biggest difference after endocarditis - finishing the antibiotics, sorting your teeth, keeping specialist follow-up and knowing your prophylaxis status.

A quiet reminder

Recovery is measured in months, not weeks.

Fatigue, deconditioning and the mental weight of a long admission are all normal - and all worth taking seriously.

  1. 01 Recovery

    Give the antibiotic course its full run

    Four to six weeks of IV treatment is standard - stopping early is the commonest way for endocarditis to relapse.

  2. 02 Dental

    Sort your teeth out

    A full dental review after endocarditis matters - poor oral health is a genuine, modifiable risk factor for the next episode.

  3. 03 Follow-up

    Keep specialist follow-up

    Cardiology review, repeat echo and a clear plan for future procedures reduce the risk of recurrence.

  4. 04 Prevention

    Know your prophylaxis status

    Some people at very high risk are advised antibiotic prophylaxis before certain dental work - your team will tell you if that applies.

Frequently asked

Everything we get asked about endocarditis.

Quick answers on diagnosis, organisms, risk factors, surgery and prophylaxis.

  • What is infective endocarditis?

    Infective endocarditis is an infection of the inner lining of the heart, most often affecting a heart valve. It is life-threatening and needs urgent hospital care, prolonged IV antibiotics and sometimes heart surgery. In the UK it is managed by a specialist endocarditis team, usually in a tertiary centre.

  • How is endocarditis diagnosed?

    Diagnosis uses the modified Duke criteria, which combine blood cultures, echocardiography and clinical features. Three sets of blood cultures are taken from separate sites at least one hour apart, ideally before antibiotics. Transthoracic echo is first-line, with transoesophageal echo used when the picture is unclear or a prosthetic valve is involved.

  • What organisms cause it?

    Staphylococcus aureus is the leading cause and is rising. Viridans streptococci, Streptococcus gallolyticus (which is linked to colonic cancer), enterococci and the HACEK group are all important. About one in ten cases are culture-negative and may be due to Coxiella burnetii, Bartonella, Brucella or Tropheryma whipplei. Fungal endocarditis is rare but serious.

  • Who is most at risk?

    People with prosthetic heart valves, previous endocarditis, unrepaired cyanotic congenital heart disease, rheumatic heart disease, mitral valve prolapse with regurgitation, hypertrophic cardiomyopathy, cardiac devices such as pacemakers, injecting drug users and those on haemodialysis or with long-term central lines.

  • When is surgery needed?

    Surgery is considered for heart failure caused by valve destruction, uncontrolled infection such as abscess or fungal disease, and to prevent embolism when vegetations are large and mobile. It is timed carefully, especially after a stroke, and done in a specialist cardiac surgery centre.

  • Do I need antibiotics before dental work?

    NICE CG64 does not recommend routine antibiotic prophylaxis for most people having dental procedures. European and American guidelines still recommend prophylaxis for those at highest risk, such as after previous endocarditis, with prosthetic valves or certain congenital heart disease. Your specialist will tell you which applies to you.

Related content

Keep reading.

Pulse Healthcare concierge

Send us your enquiry

A concierge service for UK private healthcare. We match you with the best vetted clinics and consultants in our network - they then contact you directly.

So we can match you to the right clinician close to you.

We reply to every enquiry within 24 hours (Mon–Fri). Confidential - your details are never shared outside our vetted consultant network.