Endocarditis

Question 1

What is the most common organism in community-acquired native-valve IE?

Answer 1

Streptococci (40%)

Question 2

What is the most common organism in health care–associated native-valve IE?

Answer 2

Staphylococcus aureus (52%)

Question 3

What organism causes 28% of community-acquired native-valve IE?

Answer 3

Staphylococcus aureus

Question 4

What is the most common cause of prosthetic-valve IE <2 months after surgery?

Answer 4

Staphylococcus aureus (22%)

Question 5

What is the most common cause of prosthetic-valve IE >2-12 months after surgery?

Answer 5

Coagulase-negative staphylococci (35%)

Question 6

What is the most common cause of prosthetic-valve IE >12 months after surgery?

Answer 6

Staphylococcus aureus (18%)

Question 7

What is the most common organism in TAVR-related IE?

Answer 7

Staphylococcus aureus (23%)

Question 8

What is the most common organism in CIED-related IE?

Answer 8

Coagulase-negative staphylococci (41%)

Question 9

Which group includes Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, and Kingella?

Answer 9

HACEK group (fastidious gram-negative coccobacilli)

Question 10

What is the rate of culture-negative IE in health care–associated cases?

Answer 10

3%

Question 11

What is the most common symptom of infective endocarditis?

Answer 11

Fever – 80–90%

Question 12

What is the frequency of chills and sweats in infective endocarditis?

Answer 12

40–75%

Question 13

What is the frequency of anorexia, weight loss, and malaise?

Answer 13

25–50%

Question 14

What is the frequency of a heart murmur in infective endocarditis?

Answer 14

80–85%

Question 15

What is the frequency of neurologic manifestations in endocarditis?

Answer 15

20–40%

Question 16

What is the frequency of petechiae in endocarditis?

Answer 16

10–40%

Question 17

What is a common hematologic finding in infective endocarditis?

Answer 17

Anemia – 70–90%

Question 18

What is the frequency of elevated ESR in infective endocarditis?

Answer 18

60–90%

Question 19

What is the frequency of elevated CRP in infective endocarditis?

Answer 19

> 90%

Question 20

What is the frequency of circulating immune complexes?

Answer 20

65–100%

Question 21

What is the frequency of decreased serum complement in endocarditis?

Answer 21

5–40%

Question 22

Penicillin-susceptible streptococci (S. gallolyticus, MIC ≤0.12 µg/mL) – 4-week monotherapy option?

Answer 22

• Penicillin G (2–3 mU IV q4h × 4 weeks)
• Ceftriaxone (2 g IV daily × 4 weeks)
• Vancomycin (15 mg/kg IV q12h × 4 weeks if penicillin allergy)

Question 23

Penicillin-susceptible streptococci (S. gallolyticus, MIC ≤0.12 µg/mL) – 2-week combo option?

Answer 23

• Penicillin G (2–3 mU IV q4h) or Ceftriaxone (2 g IV daily) for 2 weeks
plus
• Gentamicin (3 mg/kg/day IV/IM, single or divided doses q8h × 2 weeks)

Question 24

Relatively penicillin-resistant streptococci (MIC >0.12 to <0.5 µg/mL) – treatment option?

Answer 24

• Penicillin G (4 mU IV q4h) or Ceftriaxone (2 g IV daily) × 4 weeks
plus
• Gentamicin (3 mg/kg/day IV/IM, single or divided doses q8h × 2 weeks)
or
• Vancomycin (15 mg/kg IV q12h × 6 weeks if allergy)

Question 25

Moderately penicillin-resistant streptococci (MIC ≥0.5 and <8 µg/mL) or Granulicatella, Abiotrophia, Gemella – treatment?

Answer 25

• Penicillin G (4–5 mU IV q4h) or Ceftriaxone (2 g IV daily) × 6 weeks plus • Gentamicin (3 mg/kg/day IV/IM, single or divided doses q8h × 6 weeks) or • Vancomycin × 6 weeks

Question 26

When is a 6-week regimen preferred for PVE (prosthetic valve endocarditis)?

Answer 26

For all regimens, especially in PVE, 6-week treatment is preferred. Avoid 2-week regimen in prosthetic valve or complicated cases.

Question 27

What are the preferred regimens for treating Enterococcal endocarditis?

Answer 27

1. Penicillin G (4–5 mU IV q4h) + Gentamicin (1 mg/kg IV q8h), for 4–6 weeks • NVE: 4 weeks if symptoms <3 months; 6 weeks if >3 months • Can abbreviate gentamicin in some cases 2. Ampicillin (2 g IV q4h) + Gentamicin (1 mg/kg IV q8h), for 4–6 weeks • IV amoxicillin can replace ampicillin • Gentamicin may be abbreviated 3. Vancomycin (15 mg/kg IV q12h) + Gentamicin (1 mg/kg IV q8h), both for 6 weeks • For penicillin-allergic patients • Prefer desensitization if allergy is not immediate/urticarial 4. Ampicillin (2 g IV q4h) + Ceftriaxone (2 g IV q12h), for 6 weeks • For E. faecalis without high-level gentamicin resistance • Use if at high risk of aminoglycoside nephrotoxicity (CrCl < 50 mL/min)

Question 28

MSSA infecting native valves (no foreign devices) Treatment options?

Answer 28

• Nafcillin, oxacillin, or flucloxacillin (2 g IV q4h for 6 weeks) • Cefazolin (2 g IV q8h for 6 weeks) • Vancomycin (15 mg/kg IV q12h for 6 weeks) ## Footnote No gentamicin. Use cefazolin for non-immediate penicillin allergy. Vancomycin only for severe or immediate allergy.

Question 29

MRSA infecting native valves (no foreign devices) Treatment options?

Answer 29

• Vancomycin (15 mg/kg IV q8–12h for 6 weeks) • Daptomycin (8–10 mg/kg daily for 6 weeks) ## Footnote Rifampin not recommended.

Question 30

MSSA infecting prosthetic valves Treatment options?

Answer 30

• Nafcillin, oxacillin, or flucloxacillin (2 g IV q4h for 6–8 weeks) plus • Gentamicin (1 mg/kg IM or IV q8h for 2 weeks) plus • Rifampin (300 mg PO q8h for 6–8 weeks) ## Footnote Adjust for renal function. Await blood culture clearance before rifampin. Use MRSA regimen if penicillin allergy.

Question 31

MRSA infecting prosthetic valves Treatment options?

Answer 31

• Vancomycin (15 mg/kg IV q12h for 6–8 weeks) plus • Gentamicin (1 mg/kg IM or IV q8h for 2 weeks) plus • Rifampin (300 mg PO q8h for 6–8 weeks) ## Footnote Consider daptomycin as alternative to vancomycin. Rifampin after blood culture clearance.

Question 32

Treatment of Infective Endocarditis caused by Coxiella burnetii

Answer 32

• Doxycycline 100 mg PO q12h • PLUS Hydroxychloroquine 200 mg PO q8h • Duration: • 18 months (native valve) • 24 months (prosthetic valve) • Monitoring: Follow serology (Antiphase I IgG & IgA decrease 4-fold and IgM & Antiphase II negative) to assess response and relapse

Question 33

Treatment of Infective Endocarditis caused by Bartonella spp. (first-line)

Answer 33

• Doxycycline 100 mg PO q12h for 6 weeks • PLUS Gentamicin 3 mg/kg IV q8h for 2 weeks • If doxycycline not tolerated: Use Azithromycin 500 mg PO daily • Experts suggest continuing doxycycline for 3–6 months unless infection is surgically resected