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Antimicrobial Stewardship (AMS)

Resources to help you ensure the safe and effective use of antimicrobials in NSHA patients.

Bacterial Infective Endocarditis

Infection of the endocardial surface of the heart, most commonly the valves.

Last reviewed January 2023

  • Staphylococcus aureus most common 
  • Non-β-hemolytic streptococci such as 
    • S. gallolyticus (bovis), S. sanguinis, S. mitis, S. mutans, S. salivarius
  • Enterococcus spp.
  • HACEK group (Haemophilus sp., Aggregatibacter sp., Cardiobacterium hominis, Eikenella corrodens, and Kingella sp.)

Last reviewed January 2023

  • Refer to modified Duke Criteria for diagnostic criteria (see below)
    • Should be considered in patients with persistent fever of unknown source
    • Septic emboli without another cause
  • Obtain at least 2 sets of blood cultures from different venipuncture sites prior to antimicrobials
    • If non-acute presentation and clinically stable, obtain 3-4 sets of blood cultures separated over 24-48 hours before initiating antibiotics
    • Antibiotics given prior to cultures is most common cause of culture-negative IE
  • ECG on presentation and serially
    • New AV block (including 1st degree block) is associated with periannular complications
  • Urinalysis for hematuria
  • Echocardiogram
    • TEE more sensitive than TTE
    • If initial TEE negative but high suspicion for IE, repeat examination within 3-5 days is reasonable
  • Chest radiography to assess for septic emboli
  • Physical examination focused on assessment for metastatic sites of infection such as joint infection or vertebral osteomyelitis/discitis
  • Dental evaluation to assess for source of infection

Last reviewed January 2023

  • Multidisciplinary involvement recommended as needed: ID, Cardiology, Cardiovascular Surgery, Neurology, Addictions Medicine
  • Obtain 2 sets of blood cultures every 48 hours until negative to document clearance
  • Duration of therapy is counted from date of first negative blood culture
    • If tissue culture from valve replacement is positive, restart therapy duration from time of operation (unless patient is still bacteremic at time of surgery)
  • For regimens involving more than 1 antimicrobial, agents should be administered temporally close together

Last reviewed January 2023

  • Clinically stable with a non-acute presentation: antimicrobials can be deferred while awaiting the results of blood cultures and other diagnostic tests
  • Vancomycin and Ceftriaxone 2g IV q24h, reassess when blood culture results are available

Last reviewed January 2023

Synergy

  • Do not need to add with initial management, can await blood culture results
  • Gentamicin synergy
    • Used in IE due to:
      • Enterococcus spp. native or prosthetic valve
      • Staphylococcal prosthetic valve for initial 2 weeks of therapy
      • Some Streptococci depending on penicillin MIC
    • Verify microorganism is high-level aminoglycoside sensitive
    • Baseline and surveillance hearing tests if planning more than 14 days of aminoglycoside
    • Frequent monitoring of creatinine for toxicity and/or dose adjustment
    • See Aminoglycoside Chapter for dosing/monitoring
    • Do not use tobramycin in place of gentamicin
  • Ceftriaxone synergy
    • Can be used instead of gentamicin for synergy for ampicillin sensitive E. faecalis endocarditis (native or prosthetic)
    • Dosing is ceftriaxone 2 g IV q12h
  • Rifampin
    • Used for staphylococcal prosthetic valve infections (either S. aureus or coagulase negative staphylococci)
    • Not initiated until cultures documented negative
    • Verify microorganism sensitivity to rifampin
    • Review medication list for drug-drug interactions
    • Monitor liver enzymes during therapy

Last reviewed January 2023

  • At completion of therapy:
    • Prompt removal of PICC/vascular catheter
    • TTE (or TEE if poor windows or complex anatomy) to obtain new baseline valve function. Common for vegetation to remain visible, but persistent lesion is not a reason to extend antibiotic duration.
    • Early medical attention if unwell and obtain 3 sets of blood cultures if fever
  • Patients with suspected or confirmed IE associated with drug use should be referred to Addiction Medicine for treatment.
  • Maintain dental hygiene and administer antimicrobial prophylaxis prior to dental procedures that involve manipulation of gingival tissue or periapical region of teeth
  • Oral regimens not recommended
    • May be an option on a case-by-case basis as method of harm reduction when long-term IV or central access is not feasible

Modified Duke Criteria:

Major Criteria
  1. Blood culture positive for IE:
Typical microorganisms consistent with IE from 2 separate blood cultures:
  • Staphylococcus aureus 
  • Viridans streptococci (VGS)
  • Streptococcus gallolyticus (S. bovis)
  • HACEK group (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella and Kingella species)
  • Community acquired enterococci in the absence of a primary focus 
Microorganisms consistent with IE from persistently positive blood cultures defined as: 
  • 2 or more positive blood cultures drawn more than 12 hours apart or 
  • all 3 or a majority of 4 or more separate blood cultures (at least 1 hour between first and last sample)
Single positive blood culture for Coxiella burnetii or anti-phase 1 IgG antibody titer of greater than equal to 1:800
  1. Evidence of endocardial involvement:
  • Oscillating intracardiac mass on valve or supporting structures, in the path of regurgitant jets, or on implanted material in the absence of an alternative explanation
  • Abscess
  • New partial dehiscence of prosthetic valve
  • New valvular regurgitation (worsening or changing or pre-existing murmur not sufficient)
Minor Criteria
  1. Predisposing heart condition or injection drug use
  2. Fever (temperature greater than 38⁰C)
  3. Vascular phenomena: major arterial emboli, septic pulmonary emboli, mycotic aneurysm, intracranial hemorrhage, conjunctival hemorrhage, Janeway lesions
  4. Immunologic phenomena: glomerulonephritis, Osler nodes, Roth spots, rheumatoid factor titer 
  5. Microbiologic evidence not meeting major criteria (excludes single positive blood culture for coagulase negative staphylococci and microorganisms that do not cause IE) or serological evidence of active infection with microorganisms consistent with IE
Definite IE Pathologically proven: microorganisms showing active endocarditis demonstrated by culture or histological exam of a vegetation, intracardiac abscess sample or pathological lesions Clinical criteria (either):
  • 2 major criteria, OR
  • 1 major criteria + 3 minor criteria, OR 
  • 5 minor criteria
Possible IE
  • 1 major criteria + 1 minor criteria OR
  • 3 minor criteria
Rejected IE
  • Firm alternative diagnosis explaining evidence of IE OR
  • Resolution of IE symptoms with antibiotics for 4 days or less; OR
  • No pathological evidence of IE at surgery or autopsy with antibiotic therapy for 4 or less days OR
  • Does not meet the criteria for possible IE as above

 

Last reviewed January 2023

1. Baddour LM, et al. Infective endocarditis in adults: diagnosis, antimicrobial therapy, and management of complications: a scientific statement for healthcare professionals from the American Heart Association. Circulation. 2015;132: 1435-1486.

2. Sivak JA, et al. An Approach to Improve the Negative Predictive Value and Clinical Utility of Transthoracic Echocardiography in Suspected Native Valve Infective Endocarditis. J Am Soc Echocardiogr. 2016 Apr;29(4):315-22

3. Graupner C, et al. Periannular extension of infective endocarditis. J Am Coll Cardiol. 2002 Apr 3;39(7):1204-11.

4. Iversen K, et al. Partial Oral versus Intravenous Antibiotic Treatment of Endocarditis. N Engl J Med. 2019 Jan 31;380(5):415-424.

5. Baddour LM, et al. Infective Endocarditis in Adults: Diagnosis, Antimicrobial Therapy, and Management of Complications. Circulation. 2015;132:1435-1486.

Last reviewed January 2023