Prosthetic valve endocarditis caused by Staphylococcus epidermidis. Development of rifampin resistance during vancomycin and rifampin therapy
B. Chamovitz, R. E. Bryant, D. N. Gilbert and A. I. Hartstein
Development of rifampin-resistant Staphylococcus epidermidis was documented
in three patients receiving vancomycin and rifampin therapy for prosthetic
valve endocarditis. The minimum inhibitory concentrations and minimum
bactericidal concentrations of rifampin for the original three isolates
were 0.4 micrograms/mL or less. Organisms cultured during relapse or
prosthetic valve replacement had minimum inhibitory concentrations of
rifampin that were 12.5, 50, and greater than 100 micrograms/mL,
respectively. Surgical intervention was necessary in all patients. One
died, and one required a second prosthetic valve placement. The patients
were treated with vancomycin plus aminoglycoside following identification
of rifampin resistance. These observations suggest that vancomycin and
rifampin may not be adequate therapy for prosthetic valve endocarditis
caused by S epidermidis.
