Staphylococcus epidermidis is the most common cause of nosocomial bloodstream infection (BSI). At The University of Texas MD Anderson Cancer Center, linezolid is frequently used empirically in leukemia patients with suspected infection. Based on our internal data, roughly 30% of S. epidermidis bloodstream isolates in leukemia patients are resistant to linezolid. The purpose of this study was to assess short-term clinical outcomes in adult leukemia patients with linezolid-resistant S. epidermidis (LRSE) BSI treated empirically with linezolid.
Retrospective cohort study of all adult inpatients with leukemia and a first episode of S. epidermidis BSI treated with empiric linezolid from 7/2012 to 7/2015. Data relevant to S. epidermidisBSI were collected and correlated to adverse short-term outcome (a composite of persistent bacteremia, fever, ICU admission, or death on day 3 of bacteremia). Secondary outcomes were individual components of the primary composite endpoint. Log binomial and Cox proportional hazards regression analyses were used to adjust for confounding variables.
82 patients (mean age: 54.5 ± 17.9 years; 52% male) were included. Of these, 62% had acute myeloid leukemia, 24% had acute lymphoblastic leukemia, and 74% had relapsed or refractory disease. The overall linezolid resistance rate was 40%. Patients with LRSE were more likely to have adverse short-term clinical outcomes compared to those with linezolid-sensitive isolates (60.6% vs 34.7%; aRR 1.7 [95% CI 1.02-2.85], p=0.04). The duration of bacteremia was significantly longer in patients with LRSE (median 3 vs 5 days, aHR 0.62 [95% CI 0.39 – 0.99], p = 0.04). No differences existed between groups for the individual components of the composite endpoint with the exception of persistent bacteremia (36.4% vs 8.2%, aRR 5.2 [95% CI 1.46-18.44], p=0.01).
Patients with LRSE BSI treated empirically with linezolid experience significantly worse short-term clinical outcomes compared to patients with linezolid-susceptible infections, driven primarily by persistent bacteremia. These are the first data to show the clinical impact of linezolid resistance among S. epidermidis, which is being increasingly reported worldwide.
S. A. Folan,
J. J. Tarrand, None
S. A. Shelburne, None
I. Raad, Pfizer: Consultant , Consulting fee
V. E. Mulanovich, None
K. R. Marx, None
S. L. Aitken, Merck: Speaker's Bureau , Speaker honorarium
Theravance: Scientific Advisor , Consulting fee
Actavis: Scientific Advisor , Consulting fee