Enterococcus faecalis infective endocarditis: a pilot study of the relationship between duration of gentamicin treatment and outcome.

BACKGROUND: Because of the nephrotoxic effects of aminoglycosides, the Danish guidelines on infective endocarditis were changed in January 2007, reducing gentamicin treatment in enterococcal infective endocarditis from 4 to 6 weeks to only 2 weeks. In this pilot study, we compare outcomes in patients with Enterococcus faecalis infective endocarditis treated in the years before and after endorsement of these new recommendations. METHODS AND
RESULTS: A total of 84 consecutive patients admitted with definite left-sided E faecalis endocarditis in the period of 2002 to 2011 were enrolled. Forty-one patients were treated before and 43 patients were treated after January 1, 2007. There were no significant differences in baseline characteristics. At hospitalization, the 2 groups had similar estimated glomerular filtration rates of 66 and 75 mL/min (P=0.22). Patients treated before January 2007 received gentamicin for a significantly longer period (28 versus 14 days; P<0.001). The primary outcome, 1-year event-free survival, did not differ: 66% versus 69%, respectively (P=0.75). At discharge, the patients treated before 2007 had a lower estimated glomerular filtration rate (45 versus 66 mL/min; P=0.008) and a significantly greater decrease in estimated glomerular filtration rate (median, 11 versus 1 mL/min; P=0.009) compared with those treated after 2007.
CONCLUSIONS: Our present pilot study suggests that the recommended 2-week treatment with gentamicin seems adequate and preferable in treating non-high-level aminoglycoside-resistant E faecalis infective endocarditis. The longer duration of gentamicin treatment is associated with worse renal function. Although the certainty of the clinical outcomes is limited by the sample size, outcomes appear to be no worse with the shorter treatment duration. Randomized, controlled studies are warranted to substantiate these results.