Endocarditis Part 2

Question 1

PROSTHETIC valve IE caused by staph

therapy if MRSA vs MSSA

Answer 1

MSSA - nafcillin/oxacillin IV + rifampin IV/PO + Gentamicin IV
Naf/ox/rifamin are given for AT LEAST 6 WEEKS and gent only given for the 1st 2 weeks

MRSA - Vanco IV + Rifampin IV/PO + Gentamicin IV
vanco/rifampin are AT LEAST 6 WEEKS and gent is given for 1st 2 weeks

Question 2

pt is 80 year old woman with fevers and chills. has osler nodes and janeway lesions

TTE reveals 8mm vegetation on native mitral valve.
blood cultures reveal gram positive cocci in clusters, suggesting staph aureus

what empiric antibiotics should be started assuming normal renal fxn and NKA

Answer 2

vancomycin IV for 6 weeks

WANT TO START BROAD AND COVER FOR WORST CASE SCENARIO (MRSA)

Question 3

pt is 68 year old female with staph endocarditis

TEE reveals 4mm vegetation on prosthetic mitral valve

blood cultures positive for MRSA

what is appropriate antimicrobial therapy

Answer 3

vancomycin IV + gentamicin IV + rifampin IV/PO

vanco and rifampin for at least 6 weeks and gentamicin for 1st 2 weeks

Question 4

2 diff species of enterococcus that can cause IE

Answer 4

enterococcus faecalis and enterococcus faecium

Question 5

true or false

enterococcus faecalis and enterococcus faecium are not part of the normal flora

Answer 5

FALSE

they are normal flora in the GI tract

Question 6

enterococcal species are the ______ leading cause of infective endocarditis

Answer 6

3rd

Question 7

TRUE OR FALSE

enterococcal endocarditis is more resistant to therapy than staph and strep

Answer 7

TRUE

the MIC’s to penicillin are very high and they have intrinsic resistance to all cephalosporins

no single antibiotic will be bactericidal - always need more than 1 drug - SYNERGY

Question 8

as mentioned, a synergistic combination is almost always needed to treat enterococcal endocarditis

this is usually….

Answer 8

a cell well agent and an aminoglycoside (gentamicin)

Question 9

true or false

for enterococcal endocarditis, both native valve and prosthetic valve are treated the same

Answer 9

true - bc of the bug we’re dealing with

Question 10

enterococcal endocarditis that is penicillin and gentamicin susceptible

what are some potential therapies and why might 1 be used over another

Answer 10

Amp IV or Pen IV with gentamicin IV for 6 weeks
(possibly only 4 weeks if it’s native valve and the symptoms have been there less than 3 months)

OR

Ampicillin IV + Ceftriaxone IV for 6 weeks (this is recommended if creatinine clearance is less than 50 mL/min–aminoglycosides are hard on the kidneys)

Question 11

enterococcal endocarditis that is penicillin susceptible but gentamicin resistant

Answer 11

Ampicillin IV + Ceftriaxone IV for 6 weeks

OR

Ampicillin IV/Pen G IV + Streptomycin IV for 6 weeks
(only if streptomycin susceptible, also, streptomycin needs drug monitoring)

Question 12

how is it that we can use ceftriaxone with ampicillin in some cases of enterococcal endocarditis, but enterococcus has an intrinsic resistance to cephalosporins?

Answer 12

in combination, saturates PBP on cell membranes and gives synergy

Question 13

what class is streptomycin

Answer 13

like gentamicin - an aminoglycoside

Question 14

enterococcal endocarditis

pen resistant but susceptible to vanco and gent

Answer 14

Vanco IV + Gentamicin IV for 6 weeks

Question 15

enterococcal endocarditis

Pen resistant, gen resistant AND vanco resistant

what is therapy

Answer 15

Linezolid IV or Daptomycin IV for greater than 6 weeks

Dapto sometimes preferred by physicians bc FDA approved for right sided native valve endocarditis

also, linezolid is bacteriostatic and has lower cure rates than dapto

Question 16

1 thing that should be monitored when giving daptomycin

Answer 16

creatinine phosphokinase (CPK)

Question 17

linezolid side effects

Answer 17

bone marrow suppression - monitor platelets

DDI with SSRI’s - risk of serotonin syndrome

Question 18

pt is 70 years old with native valve enterococcal endocarditis that is penicillin and gentamicin susceptible

NKA and creatinine clearance of 30mL/min

what therapy is appropriate

Answer 18

REMEMBER - native or prosthetic doesn’t matter in enterococcal

low creatinine clearance - less than 50 - DO NOT give gentamicin

Ampicillin IV + Ceftriaxone IV for 6 Weeks

Question 19

pt is 60 years old with native valve enterococcal endocarditis that is penicillin suceptible and gentamicin resistant

NKA
CrCl of 75mL/min

what antimicrobial therapy

Answer 19

Ampicillin IV + Ceftriaxone IV for 6 weeks

Question 20

in general, the dosing of antibiotics in infective endocarditis is very high

what is an exception???

Answer 20

gentamicin

dosed on the lower end because it’s there as synergy - not as main therapy

Question 21

after initiating antibiotics, how long should it take to get negative cultures?

if they’re not negative at this point, how often should the cultures be repeated until you do get a negative result?

Answer 21

should be negative within a few days

if not, repeat every 24-72 hours until negativea

Question 22

after initiating antibiotics, how long should it take for the fever to subside

Answer 22

around 1 week

Question 23

after the antibiotics are completed, what should be done?

Answer 23

a new baseline echo

Question 24

which 2 drugs used for IE need monitoring and what are their target serum concentrations

Answer 24

vancomycin and gentamicin

Vanco target SUC is 400-600 or trough 15-20

gentamicin target peak is 3-4 and trough less than 1

Question 25

explain dosing of vanco

do we use actual or ideal body weight to estimate renal function

Answer 25

15-20mg/kg Q8-12H
(based on renal function)

USE ACTUAL BODY WEIGHT - NOT IDEAL

Question 26

maximum single dose of vancomycin

Answer 26

2 grams

Question 27

traditional dosing of gentamicin

Answer 27

1mg/kg IV Q8H

Question 28

3 ADRS of gentamicin

Answer 28

nephrotoxicity
ototoxicity
neuromuscular blockade

Question 29

rifampin 2 ADRS

Answer 29

hepatotoxic

red/orange discoloration of body secretions

Question 30

what should be monitored when taking rifampin

Answer 30

liver function tests at baseline and every 2-4 weeks during therapy
(bc hepatotoxic)

Question 31

why is rifampin a concern with drug interactions

Answer 31

it’s a CYP450 inducer – lower levels of drugs metabolized by CYP system

Question 32

2 ADRS of daptomycin and these are more frequent in what patients

Answer 32

myopathy and rhabdomyolysis

more frequent in patients on statins

Question 33

what should be monitored when giving daptomycin

Answer 33

CPK (creatinine phosphokinase) weekly and watch for muscle pains

Question 34

when should daptomycin be discontinued

Answer 34

if CPK increases greater than 5x over baseline and the patient has symptoms

OR

if CPK increases greater than 10x over baseline - even if pt doesnt have symptoms

Question 35

3 ADRS of linezolid

Answer 35

thrombocytopenia
optic neuropathy
peripehral neuropathy

Question 36

what should be monitored in pts on linezolid

Answer 36

platelet counts both at baseline and weekly

also watch for vision changes common with prolonged therapy over 2 weeks, but for IE we treat for at least 6 so have to watch

Question 37

give 5 patients considered at highest risk for endocarditis and antimicrobial prophylaxis is warranted

Answer 37

-prosthetic valve

-previous infective endocarditis

-cardiac transplant with subsequent valvulopathy (valve disease)

congenital heart disease

getting dental procedure that perforates oral mucosa or manipulating periapical region of gingival tissue

Question 38

name prophylactic drug and dosing given to a pt going for an oral procedure to prevent endocarditis

Answer 38

amoxicillin 2g PO 30-60 mins before procedure

IF PEN ALLERGIC - clindamycin 600mg