title: Treatment of vancomycin-resistant enterococcus with quinupristin/dalfopristin and high-dose ampicillin.
abstract: OBJECTIVE
  To report the successful treatment of vancomycin-resistant Enterococcus (VRE) bacteremia using the combination of quinupristin/dalfopristin and high-dose ampicillin.
  
  
  METHODS
  A 38-year-old African American woman with relapsed acute myeloid leukemia and neutropenic fever developed VRE bacteremia following 3 successive courses of vancomycin for methicillin-resistant staphylococcal infections. Treatment with linezolid was initiated; however, after 9 days of therapy, blood cultures continued to reveal VRE and the patient became febrile. The patient was subsequently switched to quinupristin/dalfopristin and high-dose ampicillin. The fever resolved and all subsequent blood cultures were negative after the initiation of combination therapy.
  
  
  CONCLUSIONS
  The emergence of VRE infections presents a treatment challenge in immunocompromised patients. When treating VRE infections in this patient population, the effectiveness of linezolid and quinupristin/dalfopristin is limited by their bacteriostatic activity when used as monotherapy. Recent in vitro data suggest synergistic activity with quinupristin/dalfopristin when used in combination with other antimicrobials in selected isolates of VRE.
  
  
  CONCLUSIONS
  Persistent VRE bacteremia was successfully treated in this neutropenic patient using the combination of high-dose ampicillin and quinupristin/dalfopristin. Case reports and in vitro data suggest that concomitant therapy with high-dose ampicillin may be an effective treatment alternative for VRE infections not responding to standard therapy.
authors.affiliation: Critical Care, Department of Pharmacy Practice, St. Louis College of Pharmacy, St. Louis, MO, USA.
authors.forename: J Audis
authors.initials: JA
authors.lastname: Bethea
authors.forename: Christine M
authors.initials: CM
authors.lastname: Walko
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Targos
mesh_terms: D000328:Adult; D000667:Ampicillin / Q000008:administration & dosage / Q000627:therapeutic use*; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D016470:Bacteremia / Q000150:complications / Q000188:drug therapy* / Q000382:microbiology; D004359:Drug Therapy, Combination; D016984:Enterococcus faecium; D005260:Female; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000150:complications / Q000188:drug therapy; D009503:Neutropenia / Q000150:complications; D013203:Staphylococcal Infections / Q000150:complications / Q000188:drug therapy; D020713:Vancomycin Resistance; D014769:Virginiamycin / Q000008:administration & dosage / Q000627:therapeutic use*
chemical_list: D000900:Anti-Bacterial Agents; D014769:Virginiamycin; C062940:quinupristin-dalfopristin; D000667:Ampicillin