Chapter 19 Infective EndocarditisFig. 19.1 An approach to the diagnostic use of echocardiography (echo).
- High-risk echocardiographic features include large and/or mobile vegetations, valvular insuffi ciency, suggestion of perivalvular extension, or secondary
ventricular dysfunction.
† For example, a patient with fever and a previously known heart murmur and no other stigmata of IE.
+High initial patient risks include prosthetic heart valves, many congenital heart diseases, previous endocarditis, new murmur, heart failure, or other stigmata of endocarditis.
Rx indicates antibiotic treatment for endocarditis. Reproduced with permission from Bayer AS, Bolger AF, Taubert KA, Wilson W, Steckelberg J, Karchmer AW,
Levison M, Chambers HF, Dajani AS, Gewitz MH, Newburger JW, Gerber MA, Shulman ST, Pallasch TJ, Gage TW, Ferrieri P. Diagnosis and management of
infective endocarditis and its complications. Circulation. 1998;98:2936–2948.
duration of therapy should begin on the fi rst day on
which blood cultures were negative in cases in which
blood cultures were initially positive. At least two
sets of blood cultures should be obtained every 24
to 48 hours until bloodstream infection is cleared.
Second, for patients with native valve endocarditis
who undergo valve resection with prosthetic valve
replacement, the postoperative treatment regimen
should be one that is recommended for prosthetic
valve treatment rather than one that is recom-
mended for native valve treatment. If the resected
tissue is culture positive, then an entire course of
antimicrobial therapy is recommended after valve
resection. If the resected tissue is culture negative,
then the recommended duration of prosthetic valve
treatment should be given less the number of days
of treatment administered for native valve infection
before valve replacement. Third, in regimens that
contain combination antimicrobial therapy, it is
important to administer agents at the same time or
temporally close together to maximize the synergis-
tic killing effect on an infecting pathogen.
Bacteriologic cure rates ≥98% may be anticipated
in patients who complete 4 weeks of therapy with
parenteral penicillin or ceftriaxone for endocarditis
caused by highly penicillin-susceptible viridans
group streptococci or S. bovis (Table 19.4). Ampicil-
lin is an alternative to penicillin and has been used
when penicillin is not available because of supply
defi ciencies. The addition of gentamicin sulfate to
penicillin exerts a synergistic killing effect in vitro on
viridans group streptococci and S. bovis. The com-
bination of penicillin or ceftriaxone together with
gentamicin results in synergistic killing in vivo in
animal models of viridans group streptococcal or
S. bovis experimental endocarditis.