Methods: We conducted a case-control study of patients with VRE bacteremia from 9/1/2007 to 12/31/2014 admitted to The Johns Hopkins Hospital. Cases were patients with VRE bacteremia resistant or intermediate to linezolid (LNVRE). Cases were matched 1:2 to bacteremic patients with linezolid-susceptible VRE isolates (LSVRE) by year of positive blood culture. Cases and controls were compared using Chi-square and Wilcoxon rank sum tests. Independent risk factors for LNVRE bacteremia were identified using logistic regression.
Results: 102 unique patients with VRE bacteremia were identified. Thirty-four LNVRE cases were matched to 68 LSVRE controls. Baseline characteristics were similar between groups with the exceptions of more LNVRE patients having solid organ transplant (26% v. 18%; p = 0.05), hematopoietic stem cell transplant (21% vs 7%; p = 0.05) or recent surgery (50% vs. 28%; p = 0.03). Most episodes of VRE bacteremia had a central line or intra-abdominal source, with intra-abdominal source being higher in the LNVRE group (41% v. 18%, p = 0.01). Logistic regression revealed that recent exposure to linezolid (OR = 18.45, p = <0.01) and meropenem (OR = 3.46, p = 0.03) were associated with development of LNVRE bacteremia. Seven out of 19 patients with LNVRE bacteremia were exposed to linezolid for inappropriate indications such as VRE colonization of stool, urine, respiratory tract or drains.
Conclusion: LNVRE bacteremia was strongly associated with prior linezolid use. While often unavoidable in ill patients with VRE infections, the necessity of linezolid use should be critically evaluated in all patients receiving this agent.
K. Dzintars, None
E. Avdic, None
S. Cosgrove, None