title: E. faecalis vancomycin-sensitive enterococcal bacteremia unresponsive to a vancomycin tolerant strain successfully treated with high-dose daptomycin.
abstract: Enterococci are part of the normal flora of the gastrointestinal tract. Intra-abdominal and genitourinary enterococcal infections may be complicated by enterococcal bacteremia. Most strains of enterococci fecal flora in antibiotic-naive patients are E. faecalis. Because nearly all E. faecalis strains are sensitive to vancomycin, E. faecalis is synonymous with vancomycin-sensitive enterococci (VSE). E. faecium, which is nearly always vancomycin-resistant, is termed vancomycin-resistant enterococci (VRE). High-grade continuous enterococcal bacteremias may result in endocarditis. Persistent VSE and VRE bacteremias may be related to device-associated infections; intra-abdominal, pelvic, and/or renal abscesses; or enterococcal endocarditis. If these causes of persistent enterococcal bacteremia are eliminated, microbiologic and antimicrobial therapy-related causes for persistent bacteremia should be considered. We present a case of a male with a E. faecalis (VSE) bacteremia unresponsive to parenteral vancomycin therapy but sensitive to vancomycin in vitro (minimum inhibitory concentration [MIC] = 1 microg/mL). The patient was treated with high-dose daptomycin (12 mg/kg intravenously [IV] q 24 hours) empirically pending susceptibility testing. High-dose daptomycin therapy cleared the patient's E. faecalis bacteremia. Subsequently, it was determined that the strain of E. faecalis was "tolerant" of vancomycin (MIC = 1 microg/mL, MBC = >64 microg/mL). We believe this is the first case of enterococcal (VSE) bacteremia unresponsive to vancomycin tolerant strain of E. faecalis that responded to high-dose daptomycin (12 mg/kg IV q 24 hours) therapy.
authors.affiliation: Infectious Disease Division, Winthrop-University Hospital, Mineola, and the State University of New York School of Medicine, Stony Brook, New York, USA.
authors.forename: Burke A
authors.initials: BA
authors.lastname: Cunha
authors.forename: Nardeen
authors.initials: N
authors.lastname: Mickail
authors.forename: Lawrence
authors.initials: L
authors.lastname: Eisenstein
mesh_terms: D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology* / Q000627:therapeutic use; D016470:Bacteremia / Q000188:drug therapy / Q000382:microbiology*; D017576:Daptomycin / Q000494:pharmacology* / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D013293:Enterococcus faecalis / Q000187:drug effects*; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy / Q000382:microbiology*; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D014640:Vancomycin / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D000900:Anti-Bacterial Agents; D014640:Vancomycin; D017576:Daptomycin