Infective endocarditis: Long-term reversibility of kidney function impairment. A 1-y post-discharge follow-up study

Treatment of Enterococcus faecalis Infective Endocarditis: A Continuing Challenge

Today, Enterococcus faecalis is one of the main causes of infective endocarditis in the world, generally affecting an elderly and fragile population, with a high mortality rate. Enterococci are partially resistant to many commonly used antimicrobial agents such as penicillin and ampicillin, as well as high-level resistance to most cephalosporins and sometimes carbapenems, because of low-affinity penicillin-binding proteins, that lead to an unacceptable number of therapeutic failures with monotherapy. For many years, the synergistic combination of penicillins and aminoglycosides has been the cornerstone of treatment, but the emergence of strains with high resistance to aminoglycosides led to the search for new alternatives, like dual beta-lactam therapy. The development of multi-drug resistant strains of Enterococcus faecium is a matter of considerable concern due to its probable spread to E. faecalis and have necessitated the search of new guidelines with the combination of daptomycin, fosfomycin or tigecycline. Some of them have scarce clinical experience and others are still under investigation and will be analyzed in this review. In addition, the need for prolonged treatment (6–8 weeks) to avoid relapses has forced to the consideration of other viable options as outpatient parenteral strategies, long-acting administrations with the new lipoglycopeptides (dalbavancin or oritavancin), and sequential oral treatments, which will also be discussed.

Enterococcus faecalis Infective Endocarditis

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.

Short-term gentamicin therapy and risk of renal toxicity in patients with bacteraemia

The renal safety of gentamicin has been questioned even when dosed once daily. This retrospective cohort study comprised adult patients with community-acquired bacteraemia and no record of chronic renal disease or malignancy. We included patients treated with gentamicin once daily for ≤ 5 days (165 exposed patients) and a balanced sample of patients not receiving aminoglycosides (150 non-exposed patients). The primary endpoint, which was an elevation in plasma creatinine of > 40 μmol/l from baseline, was equally common among exposed (7.9%) and non-exposed patients (8.7%) (p = 0.80). Among 26 patients with the primary endpoint, follow-up creatinine levels were evaluable in 21 patients and reached the normal range in 8/12 (67%) exposed patients and in 7/9 (78%) non-exposed patients (p = 0.66). Thirty-day mortality was 7.9% in exposed patients versus 7.3% in non-exposed patients (p = 0.86). We conclude that renal impairment in bacteraemic patients is independent of short-term (≤ 5 days) gentamicin administration.