Infective Endocarditis

Question 1

Challenges to IE

Answer 1

High inoculum infection (10^9 to 10^10 organisms per gram of vegetative tissue)

Organisms protected from host-immune system

Organisms in static phase

Question 2

What are the most common pathogens?

Answer 2

Streptococci (25-35%)
Staphylococci (45-70%)
Enterococci (5-18%)
Gram-negative bacilli (1.5-13%)

“Culture Negative” (1/3 to 1/2 of all cases)

Question 3

What are the different strains of streptococcus and where are they normally found?

Answer 3

Viridians group: found in the mouth and gingiva (infects through dental procedures and transient bacteremia)

Streptococcus bovis: lower GI tract(infects through the GI as well as colon cancers)

Question 4

What are the two drug/drug combos that cover VRE?

Answer 4

Dapto/Linezolid

Quinupristin/Dalfopristin

Question 5

What drugs cover HACEKs (gram negatives)

Answer 5

Amp/Sulb
Ceftriaxone
Imipenem
Ciprofloxacin

Question 6

What drugs cover Enterococcus?

Answer 6

Penicillin (about 10% of entero infections)
Ampicillin
Amp/Sulb
Imipenem
Vancomycin
Dapto/Linezolid
Quin/Dalf (e. Faecium only)

Question 7

What’s the difference in a prosthetic valve infected with streptococcus endocarditis compared to length of time to treat for a native valve?

Answer 7

The prosthetic valve needs to be treated for a longer period due to the excessive biofilm buildup

Question 8

Where is enterococcus normally found

Answer 8

In the GI tract and occasionally in the genetiurinary tract.

Question 9

Enterococcus is intrinsically resistant to what antimicrobial agents?

Answer 9

Cephalosporins
Anti-staphylococcal penicillins
Aminoglycosides
Clindamycin
Bacrim (why? No folate uptake!)

Question 10

What PBP does enterococcus change to to make it less susceptible to penicillin?

Answer 10

The change of the PBP to PBP5

Question 11

What are the two types of enterococcus resistance mechanisms?

Answer 11

1) low-level resistance which occurs in all enterococcus, usually because of the lack of drug uptake.
2) high-level resistance where the MIC increases drastically (gent with MIC >500 and streptomycin with MIC > 2,000) caused b amino glycoside-inactivating enzymes

Question 12

What is vancomycins MOA?

Answer 12

Vancomycin binds to the terminal d-ala-d-ala peptide and changes it to d-ala-d-lactate which inhibits cell wall synthesis

Question 13

What is the recent data for treatment of enterococcus (VRE) that is different from current guidelines?

Answer 13

It is recommended to use HIGH DOSE daptomycin (> 10 mg/kg/day)

Question 14

What is the first thing you should do with a patient presenting with staphylococcus aureus?

Answer 14

Get an ECHOCARDIOGRAM to see if there is infective endocarditis

Question 15

Staph aureus is frequently caused by…

Answer 15

IV drug abuse
Central venous catheters
Valve replacement

Question 16

What’s recently discovered about gentamicin use in staphylococcus treatment in native valve infections?

Answer 16

Gent has been shown to be nephrotoxic at low dose use with NATIVE valve infective endocarditis.