Endocarditis Part 2 Flashcards
PROSTHETIC valve IE caused by staph
therapy if MRSA vs MSSA
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
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
vancomycin IV for 6 weeks
WANT TO START BROAD AND COVER FOR WORST CASE SCENARIO (MRSA)
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
vancomycin IV + gentamicin IV + rifampin IV/PO
vanco and rifampin for at least 6 weeks and gentamicin for 1st 2 weeks
2 diff species of enterococcus that can cause IE
enterococcus faecalis and enterococcus faecium
true or false
enterococcus faecalis and enterococcus faecium are not part of the normal flora
FALSE
they are normal flora in the GI tract
enterococcal species are the ______ leading cause of infective endocarditis
3rd
TRUE OR FALSE
enterococcal endocarditis is more resistant to therapy than staph and strep
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
as mentioned, a synergistic combination is almost always needed to treat enterococcal endocarditis
this is usually….
a cell well agent and an aminoglycoside (gentamicin)
true or false
for enterococcal endocarditis, both native valve and prosthetic valve are treated the same
true - bc of the bug we’re dealing with
enterococcal endocarditis that is penicillin and gentamicin susceptible
what are some potential therapies and why might 1 be used over another
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)
enterococcal endocarditis that is penicillin susceptible but gentamicin resistant
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)
how is it that we can use ceftriaxone with ampicillin in some cases of enterococcal endocarditis, but enterococcus has an intrinsic resistance to cephalosporins?
in combination, saturates PBP on cell membranes and gives synergy
what class is streptomycin
like gentamicin - an aminoglycoside
enterococcal endocarditis
pen resistant but susceptible to vanco and gent
Vanco IV + Gentamicin IV for 6 weeks
enterococcal endocarditis
Pen resistant, gen resistant AND vanco resistant
what is therapy
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
1 thing that should be monitored when giving daptomycin
creatinine phosphokinase (CPK)
linezolid side effects
bone marrow suppression - monitor platelets
DDI with SSRI’s - risk of serotonin syndrome
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
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
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
Ampicillin IV + Ceftriaxone IV for 6 weeks
in general, the dosing of antibiotics in infective endocarditis is very high
what is an exception???
gentamicin
dosed on the lower end because it’s there as synergy - not as main therapy
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?
should be negative within a few days
if not, repeat every 24-72 hours until negativea
after initiating antibiotics, how long should it take for the fever to subside
around 1 week
after the antibiotics are completed, what should be done?
a new baseline echo
which 2 drugs used for IE need monitoring and what are their target serum concentrations
vancomycin and gentamicin
Vanco target SUC is 400-600 or trough 15-20
gentamicin target peak is 3-4 and trough less than 1
explain dosing of vanco
do we use actual or ideal body weight to estimate renal function
15-20mg/kg Q8-12H
(based on renal function)
USE ACTUAL BODY WEIGHT - NOT IDEAL
maximum single dose of vancomycin
2 grams
traditional dosing of gentamicin
1mg/kg IV Q8H
3 ADRS of gentamicin
nephrotoxicity
ototoxicity
neuromuscular blockade
rifampin 2 ADRS
hepatotoxic
red/orange discoloration of body secretions
what should be monitored when taking rifampin
liver function tests at baseline and every 2-4 weeks during therapy
(bc hepatotoxic)
why is rifampin a concern with drug interactions
it’s a CYP450 inducer – lower levels of drugs metabolized by CYP system
2 ADRS of daptomycin and these are more frequent in what patients
myopathy and rhabdomyolysis
more frequent in patients on statins
what should be monitored when giving daptomycin
CPK (creatinine phosphokinase) weekly and watch for muscle pains
when should daptomycin be discontinued
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
3 ADRS of linezolid
thrombocytopenia
optic neuropathy
peripehral neuropathy
what should be monitored in pts on linezolid
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
give 5 patients considered at highest risk for endocarditis and antimicrobial prophylaxis is warranted
-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
name prophylactic drug and dosing given to a pt going for an oral procedure to prevent endocarditis
amoxicillin 2g PO 30-60 mins before procedure
IF PEN ALLERGIC - clindamycin 600mg
