Emergence of Resistance to Daptomycin during Treatment of Vancomycin-Resistant Enterococcus faecalis Infection

Abstract

SIR—Daptomycin is a recently approved antibiotic intended for the treatment of complicated soft-tissue infection. It has in vitro bactericidal activity against gram-positive pathogens [1–5]. We report the case of a 64-year-old woman with cryptogenic cirrhosis who had recently begun hemodialysis with a tunneled intravenous catheter. In May 2004, she presented with hypotension to a community hospital in Indiana and was found to have high-grade bacteremia due to ampicillin-susceptible, vancomycin-resistant Enterococcus faecalis (isolates 1 and 2 in figure 1). Because of her history of penicillin allergy, she was treated with linezolid, and the hemodialysis catheter was removed. Results of culture of the catheter's tip were positive for E. faecalis. Because the patient developed thrombocytopenia, treatment with linezolid was discontinued. The patient was later discharged from the hospital with a prescribed regimen of oral ciprofloxacin. A few days later, she was rehospitalized with fever and blood culture results that were positive for E. faecalis (isolate 3 in figure 1). Treatment with daptomycin and amikacin was initiated in June 2004. The patient's hemodialysis catheter was again removed. Findings of a transesophageal echocardiogram were negative for vegetations. Results of additional blood cultures were negative for E. faecalis, and a new hemodialysis catheter was inserted. The patient was discharged from the hospital with a prescribed regimen of daptomycin 400 mg q48h in addition to amikacin during hemodialysis.