Enterococcal endocarditis: can we win the war?

Abstract

Treatment of enterococcal infections has long been recognized as an important clinical challenge, particularly in the setting of infective endocarditis (IE). Furthermore, the increase prevalence of isolates exhibiting multidrug resistance (MDR) to traditional anti-enterococcal antibiotics such as ampicillin, vancomycin and aminoglycosides (high-level resistance) poses immense therapeutic dilemmas in hospitals around the world. Unlike IE caused by most isolates of Enterococcus faecalis, which still retain susceptibility to ampicillin and vancomycin, the emergence and dissemination of a hospital-associated genetic clade of multidrug resistant Enterococcus faecium, markedly limits the therapeutic options. The best treatment of IE MDR enterococcal endocarditis is unknown and the paucity of antibiotics with bactericidal activity against these organisms is a cause of serious concern. Although it appears that we are winning the war against E. faecalis, the battle rages on against isolates of multidrug-resistant E. faecium.

Figures

Fig. 1

Suggested therapeutic alternatives for the treatment of E. faecalis IE with isolates exhibiting different susceptibility patterns; authors preferred options are bolded and underlined. (1) Rare cases of β-lactamase producing strains. (2) Consider doses of 8–12 mg/kg. For penicillin allergy, vancomycin or desensitization is suggested. If unable to desensitize, high-dose daptomycin plus gentamicin or streptomycin (in the absence of HLRAG) or high-dose daptomycin plus another agent (if the organism exhibits HLRAG) should be considered. HLRAG high-level resistance to aminoglycosides

Fig. 2

Suggested therapeutic regimens for the treatment of E. faecium IE with isolates exhibiting different susceptibility patterns, Authors’ preferred choices are bolded and underlined. (1) Consider doses up to 30 g/day. (2) Consider doses of 10–12 mg/kg. (3) If imipenem MIC<32 mg/L. (4) Recommended by the American Heart Association for the treatment of IE. (5) Agents with possible activity include ampicillin, doxycycline, rifampin, tigecycline and fluoroquinolones. HLRAG high-level resistance to aminoglycosides; DAP daptomycin; Q/D quinupristin-dalfopristin