title: Successful treatment of persistent bacteremia due to vancomycin-resistant, ampicillin-resistant Enterococcus faecium.
abstract: Emergence of vancomycin-resistant enterococci has become an increasing problem in many medical centers. We report a liver transplant recipient with vancomycin-resistant Enterococcus faecium bacteremia who was successfully treated using very high dose continuous infusion ampicillin/sulbactam, plus gentamicin after he remained bacteremic on high dose ampicillin and gentamicin. At our institution, 83% of E. faecium isolates from 1994 were inhibited by ampicillin/sulbactam compared to 66% for ampicillin at an MIC < or = 64 micrograms/ml. None of these strains produced beta-lactamase, suggesting sulbactam may have an unexplained beneficial effect against some enterococci. Although an MIC of < or = 8 micrograms/ml is required for ampicillin to be considered active against enterococci, much higher levels of ampicillin or ampicillin/sulbactam are safely achievable. The response of our patient and the reported in vivo data have implications for future treatment of this pathogen, and may necessitate a reevaluation of susceptibility interpretation guidelines by clinical laboratories, and therapeutic drug dosing by clinicians.
authors.affiliation: Department of Medicine, Northwestern Memorial Hospital, Chicago, Illinois, USA.
authors.forename: E T
authors.initials: ET
authors.lastname: Mekonen
authors.forename: G A
authors.initials: GA
authors.lastname: Noskin
authors.forename: D M
authors.initials: DM
authors.lastname: Hacek
authors.forename: L R
authors.initials: LR
authors.lastname: Peterson
mesh_terms: D000368:Aged; D000667:Ampicillin / Q000494:pharmacology; D000668:Ampicillin Resistance; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000188:drug therapy* / Q000382:microbiology*; D048909:Diabetes Complications; D004352:Drug Resistance, Microbial; D016984:Enterococcus faecium; D016908:Gram-Positive Bacterial Infections / Q000188:drug therapy* / Q000382:microbiology*; D006801:Humans; D016031:Liver Transplantation; D008297:Male; D008826:Microbial Sensitivity Tests; D010406:Penicillins / Q000494:pharmacology; D014640:Vancomycin / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D010406:Penicillins; D014640:Vancomycin; D000667:Ampicillin