Daptomycin therapy for Gram-positive bacterial infections: a retrospective study of 30 cardiac surgery patients

Introduction

Daptomycin is the first in a class of agents known as lipopeptides, used for the treatment of Gram-positive infections. The aim of this study was to evaluate the outcome in patients who were treated with daptomycin in a 12-month period.

Methods

A retrospective review of Onassis Cardiac Surgery Center medical records. Clinical information, including patient demographics and clinical outcome, was analyzed. Primary endpoints were resolution of signs and symptoms of infection and discharge from hospital.

Results

Thirty inpatients were treated with daptomycin (27 men, median age 60.6 years, mean hospital stay 55 days). Seven patients had bloodstream infection (BSI) (six coagulase-negative staphylococcus (CNS), one methicillin-susceptible Staphylococcus aureus (MSSA)), six patients had catheter-related BSI (five CNS, one vancomycin-resistant enterococcus (VRE)), eight patients had nonbacteremic catheter-related infection (seven CNS, one VRE), two patients had wound infection caused by MSSA and one patient had defibrillator-wire endocarditis caused by CNS. Seven patients received daptomycin as empiric therapy without laboratory documentation. All bacterial isolates were tested for susceptibility to daptomycin (MIC <2 μg/ml was considered sensitive). Most patients received daptomycin at a dosage of 4–6 mg/kg intravenously every 24 hours. The dosing frequency was adjusted to once every 48 hours or thrice weekly in all patients who had received hemodialysis. Prior and concomitant antibiotic therapy had been administered to all patients.

Overall, 22 (73.3%) of the 30 patients improved and were discharged. Eight patients died of complications of their underlying medical conditions. CNS was the most common pathogen (19 patients, six of whom died). No adverse events were attributed to daptomycin.

Conclusion

Given the limitations of this registry because of its retrospective nature, daptomycin appears promising for the treatment of Gram-positive bacteremia, including catheter-related BSI by CNS. It has a safety profile similar to other agents commonly administered. Clinical experience will help define its role in the treatment of catheter-related BSI, foreign body endocarditis and multidrug-resistant Gram-positive bacteremia.