How endocarditis is treated:
antibiotics, treatment duration and when surgery is needed

Article written and reviewed by Dr Luca Moretti

Infective endocarditis is treated with antibiotics or, in fungal forms, with antifungal drugs selected according to the causative microorganism. A substantial proportion of patients also need surgery on the valve or infected material. Treatment is normally started in hospital because the disease can rapidly cause heart failure, emboli, sepsis or other complications.
There is therefore no single “antibiotic for endocarditis.” Treatment changes according to the pathogen, its susceptibility to drugs, the presence of a native or prosthetic valve, renal function and any complications.

Treatment may include:

• initial intravenous antibiotics selected empirically after blood cultures;
• switching to targeted therapy once the microorganism has been identified;
• microbiological, clinical and echocardiographic monitoring during treatment;
• in selected stable patients, continuation outside hospital or with specific oral regimens;
• surgery when the valve is severely damaged, infection is uncontrolled or embolic risk is high;
• follow-up after treatment ends to detect recurrence and residual valvular damage.

The monograph on infective endocarditis describes antimicrobial regimens for different pathogens in detail. This guide instead answers the most common practical questions: why treatment lasts for weeks, when it is possible to leave hospital and in which situations antibiotics alone are not sufficient.

How antibiotics are chosen and why blood cultures are obtained first

When suspicion of endocarditis is concrete, blood cultures are obtained before antibiotics are started, except in emergencies in which treatment cannot be delayed. After blood samples have been collected, if the clinical picture requires immediate treatment, empirical antibiotics are chosen to cover the most likely microorganisms on the basis of the type of endocarditis, presence of prosthetic material, healthcare exposures and patient characteristics.
When the laboratory identifies the pathogen and provides susceptibility testing, therapy is normally narrowed and targeted. This makes it possible to use the most appropriate drug, limit unnecessary toxicity and increase the likelihood of eradicating the infection.

Treatment is complex because microorganisms within vegetations may be located inside aggregates of fibrin and platelets, where drug penetration and immune system activity are less effective. A biofilm may also develop on prosthetic material, making eradication of infection even more difficult.
For this reason, endocarditis is not treated like a common respiratory or urinary infection, and independently taking leftover antibiotics kept at home is inappropriate. Partial treatment may temporarily reduce symptoms, render blood cultures negative and complicate both diagnosis and selection of definitive therapy.

How long treatment lasts and when it can continue outside hospital

Duration is measured in weeks and depends mainly on the microorganism, the valve involved and clinical response. In native valve endocarditis, guideline-recommended regimens may last 2 to 6 weeks, whereas in prosthetic valve endocarditis treatment is generally longer and lasts at least 6 weeks.
The fact that fever disappears after a few days therefore does not mean that the infection has already been cured. Treatment must reach and sterilize vegetations and reduce the risk of recurrence.

Traditionally, the entire course was administered intravenously. Today, in carefully selected patients, a two-phase strategy is possible. ESC guidelines allow that, after an initial phase of intravenous therapy and once clinical stability has been achieved, some patients may complete treatment with outpatient parenteral antimicrobial therapy or with specific oral combinations. In general, this option is assessed after at least 10 days of appropriate intravenous treatment, or after at least one week following corrective surgery, and requires clinical and echocardiographic reassessment.
It is not a shortcut applicable to everyone. Instability, abscesses, difficult-to-treat microorganisms, absorption problems, unreliable follow-up or other complications may make continued hospitalization and intravenous therapy necessary.

During treatment, temperature, symptoms, blood cultures, renal and liver function, complete blood count and other parameters relevant to the drugs being used are monitored. Echocardiography is repeated when needed to assess vegetations, valve function and the development of complications. Persistent fever, new positive blood cultures or clinical deterioration require reassessment of the infectious focus and treatment strategy.

When antibiotics are not enough and surgery is needed

The three major indications for surgery in endocarditis are heart failure, uncontrolled infection and prevention of embolism. This does not mean that everyone with a vegetation should undergo surgery: the benefit of the procedure must be weighed against surgical risk and the specific characteristics of the infection.
Heart failure may occur when endocarditis destroys a valve, causes severe regurgitation or, more rarely, obstruction. Severe dyspnea, pulmonary edema or shock may make very urgent surgery necessary.

Infection is considered uncontrolled when, despite appropriate therapy, it continues to progress or extends into tissues around the valve. Abscesses, pseudoaneurysms, fistulas, new prosthetic valve dehiscence, persistent bacteremia or certain microorganisms that are particularly difficult to eradicate may shift the decision toward surgery.
The third issue is embolism. A vegetation can fragment and send infected material especially to the brain or other organs. The size, mobility and location of the vegetation, the microorganism and previous embolic events all contribute to estimating risk and deciding whether early surgery could reduce it.

Surgery may consist of valve repair when technically possible or valve replacement. During the operation, infected tissue is removed and sent for microbiological, histological and molecular testing. Antibiotic therapy continues after surgery according to the microorganism and clinical picture.
The decision and timing of surgery are ideally discussed by the Endocarditis Team. In complex cases, timing is an integral part of treatment: waiting too long may allow the disease to progress, whereas operating in an inappropriate situation may expose the patient to risk without sufficient benefit.

Prosthetic valve endocarditis, fungi and other cases requiring special strategies

Endocarditis involving a prosthetic valve is more difficult to eradicate and is treated for longer than most forms involving native valves. Biofilm, infection around the prosthetic annulus and the possibility of dehiscence or abscess make very close monitoring and often early cardiac surgical assessment necessary.
More recent recommendations have also modified some traditional regimens: for example, the 2026 AHA Scientific Statement emphasizes that in staphylococcal prosthetic valve endocarditis, routine addition of gentamicin is not recommended when the risks outweigh the benefits.

Fungal endocarditis is rare but particularly severe. It may require high-dose antifungal therapy, surgery and, in some cases, very prolonged or lifelong suppressive treatment. Infections associated with pacemakers, defibrillators or other devices also require specific strategies that may include complete removal of the infected system.
For this reason, treatment duration cannot be taken from a generic table without knowing the clinical context.

Can endocarditis be cured? What happens after treatment ends

Yes, endocarditis can be cured, but it remains a serious disease. Prognosis depends on age and comorbidities, the microorganism, the presence of a prosthetic valve, valvular damage, neurological or septic complications and whether surgery can be performed when indicated. Even after the infection has been eradicated, valvular regurgitation may remain and require follow-up or subsequent treatment.
Once treatment has ended, follow-up aims to identify recurrence, new infection, heart failure and progression of valvular damage early.

Persistent or recurrent fever after discharge, new chills, worsening dyspnea or rapid deterioration in general condition should not be managed by independently changing antibiotics. They should be reported to the physician because they may require new blood cultures and cardiology reassessment.
Anyone who has already had endocarditis also belongs to the high-risk groups for a new episode and should receive specific guidance on prevention and prophylaxis for procedures for which it is recommended.

Frequently asked questions about endocarditis treatment

Can endocarditis be cured completely?
Yes, many patients recover from the infection. In some, however, valvular damage remains and requires follow-up or surgery even after microbiological cure.

How long does antibiotic treatment last?
It depends on the microorganism and the valve. Native valve treatment may generally last 2-6 weeks; prosthetic valve treatment is normally at least 6 weeks.

Is it necessary to remain in hospital for all the weeks of treatment?
Not always. After an initial phase, and in selected clinically stable patients, the team may consider outpatient intravenous therapy or specific oral combinations with close follow-up.

When is surgery necessary?
Especially when endocarditis causes heart failure because of severe valvular damage, when infection is uncontrolled or extends around the valve, and in some patients with a high risk of embolism.

Can the antibiotic be stopped when the fever disappears?
No. Resolution of fever does not demonstrate that the vegetations have been sterilized. The prescribed duration should be completed unless the treating team decides to modify it.