Endocarditis, infective

I33.0

GENERAL MEASURES

Bed rest.

Early surgical intervention in acute fulminant and prosthetic valve endocarditis is often indicated. Consider surgery if there is heart failure, embolism, large vegetations on echocardiography, heart block, evidence of persistent infection despite antibiotics or renal impairment. Refer these patients promptly.

LoEIII

MEDICINE TREATMENT

Treat accompanying complications, e.g. cardiac failure. Such treatment should not delay referral.

Antibiotic therapy

It is essential to do at least 3 blood cultures, taken by separate venipunctures, before starting antibiotics.
In patients with subacute presentation and no haemodynamic compromise, wait for the results of blood culture before starting antibiotics.
Empiric treatment is indicated in patients with a rapidly fulminant course or with severe disease only.
Aminoglycoside therapy should be monitored with trough levels for safety.
Duration of therapy given is the minimum and may be extended based on the response (clinical and laboratory).

Severe penicillin-allergic patients, or methicillin resistant staphylococcal infections: (Z88.0)

  • Vancomycin, IV, 20 mg/kg 12 hourly, is the antibiotic of choice. It is essential to monitor trough concentrations of vancomycin regularly and adjust doses accordingly, starting after the third dose.

LoEIII [55]

Empiric therapy

Native
valve
  • Benzylpenicillin (penicillin G), IV, 5 MU 6 hourly for 4 weeks

    • AND
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 2 weeks. (See link below, for guidance on prescribing).

    •  
    If staphylococcal infection is suspected (acute onset):
    ADD
  • Cefazolin, IV, 2 g, 8 hourly.
    		•
    Prosthetic
    valve*
  • Vancomycin, IV, 20 mg/kg 12 hourly for 6 weeks.

    • AND
  • Rifampicin, oral, 7.5 mg/kg 12 hourly for 6 weeks.

    • AND
  • Gentamicin, IV , 1.5 mg/kg 12 hourly for 2 weeks. (See link below for guidance on prescribing).
    		•

    *All cases of prosthetic valve endocarditis should be referred.

    Directed therapy (native valve)

    Streptococcal

    Fully susceptible to penicillin
    MIC: <0.2 mg/L
  • Benzylpenicillin (penicillin G), IV, 5 MU 6 hourly for 4 weeks.
    		•
    Moderately
    susceptible
    MIC: 0.12–0.5 mg/L
  • Benzylpenicillin (penicillin G), IV, 5 MU 6 hourly for 4 weeks.

    • AND
  • Gentamicin, IV,1.5 mg/kg 12 hourly for 2 weeks (see link below for guidance on prescribing).
    		•
    Moderately resistant
    MIC: 0.5–4 mg/L
    Enterococci and
    Abiotrophia spp. (nutritionally variant streptococci)
  • Benzylpenicillin (penicillin G), IV, 5 MU 6 hourly for 4 weeks.

    • AND
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 4 weeks.


    • 6 weeks of therapy may be required in cases with a history of >3 months, or mitral or prosthetic valve involvement (see link below for guidance on prescribing).
    Fully resistant
    MIC: >4 mg/L
  • Vancomycin, IV, 20 mg/kg 12 hourly for 6 weeks.

    • AND
  • Gentamicin, IV, 1.5 mg/kg 12 hourly for 6 weeks (see Link below for guidance on prescribing).
    		•

    Enterococcal

    Fully susceptible to penicillin
    MIC: <4 mg/L
  • Benzylpenicillin (penicillin G), IV, 5 MU 6 hourly for 4 weeks.
    		•
    Moderately resistant
    MIC: 0.5–4 mg/L
    Enterococci and Abiotrophia spp. (nutritionally variant streptococci)
  • Benzylpenicillin (penicillin G), IV, 5 MU 6 hourly for 4 weeks.

    • AND
  • Gentamicin, IV, 1 mg/kg 8 hourly for 2 weeks.


    • 6 weeks of therapy may be required in cases with a history of >3 months, or mitral or prosthetic valve involvement (see link below for guidance on prescribing).
      • LoEIII [56]
    Penicillin-resistant
    MIC ≥ 4 mg/L or significant b-lactam allergy
    AND
    Sensitive to vancomycin MIC: ≤4 mg/L     		Refer.

    Staphylococcal (cloxacillin/methicillin sensitive)

    S. aureus
  • Cefazolin, IV, 2g 8 hourly for 4 weeks.

    • If necessary, add:
  • Gentamicin, IV, 6 mg/kg daily for the first 3–5 days (see Link below for guidance on prescribing).

    • The benefit of adding an aminoglycoside has not been established.
    Coagulase-negative staphylococci Consult expert opinion on correct diagnosis in this setting.

    Staphylococcal (cloxacillin/methicillin resistant) or methicillin sensitive with significant beta-lactam allergy

    S. aureus
  • Vancomycin, IV, 20 mg/kg 12 hourly for 4 weeks.
    		•
    Coagulase-negative staphylococci Consult expert on correct on antibiotic choice.

    Directed therapy for prosthetic valve endocarditis

    Duration of therapy is usually a minimum of at least 6 weeks.
    Seek expert opinion on antibiotic choice and the need for referral for repeat cardiac surgery early in the course of treatment.

    Endocarditis prophylaxis
    Cardiac conditions

    Patients with the following cardiac conditions are at high risk of developing infective endocarditis:

    • Acquired valvular heart disease with stenosis or regurgitation.
    • Patients with prosthetic heart valves.
    • Structural congenital heart disease, including surgically corrected or palliated structural conditions, but excluding isolated atrial septal defect, fully repaired ventricular septal defect or fully repaired patent ductus arteriosus.
    • Patients who have suffered previous endocarditis.

    Procedures requiring prophylaxis

    Antibiotic prophylaxis is recommended for all dental procedures that involve manipulation of either the gingival tissue or the peri-apical region of the teeth.
    Antibiotic prophylaxis is not recommended for patients who undergo a gastro-intestinal or genito-urinary procedure.

    Prophylaxis (Z29.2)

    Maintain good dental health.
    This is the most important aspect of prophylaxis.
    Refer all patients to a dental clinic/dental therapist for assessment and on-going dental care.

    • Amoxicillin, oral, 2 g one hour before the procedure.

    If patient cannot take oral:

    • Ampicillin, IV/IM, 2 g one hour before the procedure.

    Severe penicillin allergy: (Z88.0)

    • Clindamycin, oral, 600 mg one hour before the procedure.

    If patient cannot take oral:

    • Clindamycin IV, 600 mg one hour before the procedure.

    The NICE review noted the lack of a consistent association between interventional procedures and development of infective endocarditis, and that the efficacy of antibiotic prophylaxis is unproven. It further commented that because the antibiotic is not without risk, there is a potential for a greater mortality from severe hypersensitivity than from withholding antibiotics.

    It is very difficult to extrapolate from these guidelines to a South African situation where good dental hygiene may be lacking and valvular heart disease is common. Practitioners need to weigh the risk of the underlying heart disease (particularly previous successfully treated endocarditis) and the essential need for ongoing antibiotic stewardship.

    LoEIII [57]