Table 2.

Therapeutic options for the treatment of vancomycin-resistant Enterococcus faecium infective endocarditis

Agents	Comments
Linezolid	• Suggested by the AHA/IDSA guidelines for IE [9]
	• Bacteriostatic agent
	• Toxicities (hematological and neurological) may be a problem when used for IE that requires ca. 6 weeks of therapy
	• Efficacy uncertain
Q/D	• Suggested by the AHA/IDSA guidelines for IE [9]
	• Bactericidal in vitro, however, such activity may be compromised in vivo by the presence of erm genes that confer resistance to quinupristin (common in clinical isolates of E. faecium) [30]
	• Frequent reports of side effects including infusion site (needs central venous access), myalgias, drug interactions
	• High likelihood of failures when used as monotherapy
	• Combination with other agents may be of clinical benefit (see text)
Daptomycin	• Bactericidal in vitro but not FDA approved for E. faecium
	• Potential of developing resistance during therapy.
	• Higher doses (8–10 mg/kg/day) generally recommended against E. faecium [60]
	• Patients infected with DAP-susceptible isolates with MICs close to the breakpoint (3–4 μg/mL) may be at high risk of therapeutic failure and recurrence [57••].
	• Combination with other agents such as β-lactams (ampicillin or ceftaroline) or tigecycline or aminoglycosides (when not exhibiting HLRAG) may be of clinical benefit to increase likelihood of microbiological eradication and decrease development of DAP resistance during therapy.

AHA American Heart Association, IDSA Infectious Disease Society of America, IE infective endocarditis, HLARG high-level resistance to aminoglycosides, Q/D quinupristin/dalfopristin, DAP daptomycin