If the organism is resistant to all available aminoglycosides, such adjunctive treatment should be omitted. In this situation, if the organism is susceptible to a fluoroquinolone, animal studies of therapy for foreign-body infection suggest that a fluoroquinolone can be used instead of gentamicin.184 Thus, although clinical data are not available to support the practice, selection for fluoroquino- lone resistance during treatment can occur, and prevalent fluo- roquinolone resistance among CoNS will limit its use, it may reasonable to use a fluoroquinolone in this setting. PVE, particularly when onset is within 12 months of cardiac valve implantation and an aortic valve prosthesis is involved, is frequently complicated by perivalvular or myo- cardial abscesses or valvular dysfunction.136 Surgery is often required in these patients and may be lifesaving. As noted above, CoNS may become resistant to rifampin during therapy for PVE. Because of the potential for changes in the patterns of antibiotic susceptibility during therapy, organisms recov- ered from surgical specimens or blood from patients who have had a bacteriological relapse should be carefully retested for complete antibiotic susceptibility profiles. Although published data on combinations of antimicrobial therapy are limited, we suggest that PVE caused by oxacillin- susceptible CoNS should be treated with nafcillin or oxacillin plus rifampin in combination with gentamicin for the first 2 weeks of therapy. A first-generation cephalosporin or vanco- mycin may be substituted for nafcillin/oxacillin for patients who are truly allergic to penicillin. Recommendations 1. Vancomycin and rifampin are recommended for a minimum of 6 weeks, with the use of gentamicin lim- ited to the first 2 weeks of therapy (Class I; Level of Evidence B). 2. If CoNS are resistant to gentamicin, then an amino- glycoside to which they are susceptible may be con- sidered (Class IIb; Level of Evidence C). 3. 