Daptomycin therapy for vancomycin-resistant enterococcal bacteremia: a retrospective case series of 30 patients.

STUDY OBJECTIVE

To determine clinical and microbiologic outcomes of daptomycin for the treatment of bacteremia caused by vancomycin-resistant enterococci (VRE).

DESIGN

Retrospective medical record review.

SETTING

Academic tertiary care hospital.

PATIENTS

Thirty patients (median age 59 yrs, range 19-79 yrs, 50% male) who received daptomycin for the treatment of VRE bacteremia between January 2004 and July 2007.

MEASUREMENTS AND MAIN RESULTS

Patients were included if they received daptomycin and had a blood culture positive for VRE at the time daptomycin was started. The primary end point was microbiologic cure, defined as negative blood cultures for VRE at the end of therapy. Secondary outcomes were clinical outcomes, adverse events, and occurrence of elevated creatine kinase levels. Clinical outcomes were judged as positive, negative, or indeterminate. The median Acute Physiology and Chronic Health Evaluation (APACHE) II score was 17 (range 7-34), and 20 patients (67%) were in the intensive care unit. Patients received daptomycin for a median of 13 days (range 1-42 days), and the median dose administered was 6 mg/kg (range 3.7-8 mg/kg). Microbiologic cure was achieved in 24 patients (80%), and clinical success occurred in 17 patients (59% [one patient had an indeterminate clinical outcome and was excluded from this analysis]). All patients with a positive clinical outcome had microbiologic cure, six patients who died had microbiologic cure, and all patients with microbiologic failure died. On multivariable logistic regression, higher APACHE II score was associated with a lower chance of microbiologic success (adjusted odds ratio [AOR] 0.73, 95% confidence interval [CI] 0.56-0.95). Lower APACHE II score (AOR 0.86, 95% CI 0.74-1.0) and daptomycin dose of 6 mg/kg or more (AOR 7.29, 95% CI 1.02-52.0) were associated with clinical success. Adverse drug events possibly attributable to daptomycin were uncommon. Three patients had fever possibly related to daptomycin, and two patients had mild elevations of creatine kinase level.

CONCLUSION

Our experience suggests that daptomycin may be an acceptable option for VRE bacteremia; however, larger studies should be performed before this antimicrobial is routinely used for this indication.