Risk Factors and Outcomes of Vancomycin-Resistant vs. Vancomycin-Sensitive Enterococcal Blood Stream Infections in Patients with Acute Myeloid Leukemia

Abstract

BackgroundEnterococci are commensal of the gastrointestinal tract known to cause blood stream infections (BSIs). Studies have shown increased mortality from enterococcal BSI in neutropenic patients, indicating Vancomycin-resistant Enterococcal (VRE) infections causing increased mortality. Whether these differences in mortality apply to AML patients is unknown. The objectives of this study are to compare the risk factors and outcomes between VRE & VSE BSIs in AML patients.MethodsWe conducted a single center, retrospective cohort study of patients with enterococcal BSIs at H. Lee Moffitt Cancer Center from July 2011 to October 2015. Records were searched to identify AML patients with enterococcal BSI. Enterococcal species, neutropenia duration, Vancomycin exposure, VRE colonization, 7 and 30 day mortality, age, sex, length of stay, stem cell transplant & central line status were compared. We conducted statistical tests and Kaplan-Meier plot to analyze mortality trends.ResultsThere were a total of 77 AML patients with enterococcal BSI. Forty-two (54.5%) were caused by VRE. E. faecalis and E. faecium accounted for 28.5% and 62.3% of BSI respectively. The E. faecalis isolates were more likely to be VSE (83% vs. 8.3 %, P < 0.001) and E. fecium isolates to be VRE (71% vs. 29%, P < 0.001). Duration of neutropenia was significantly longer (27.3 vs. 20.7 days, P < 0.005) among AML patients with VRE BSI. Recent Vancomycin use and VRE colonization were significantly associated with VRE BSI. There were no significant differences in duration of bacteremia, length of stay and 7 and 30-day mortality between VRE vs. VSE BSI.Conclusion Enterococcal infections among AML patients are significantly more likely to be caused by Vancomycin-resistant E. faecium. The risk is increased by VRE colonization and Vancomycin exposure. The absence of statistical difference in 7 or 30-day mortality between VRE and VSE enterococcal BSI in our AML patients could indicate that in a homogenous group of patients, host and treatment-related factors may influence mortality more than species or susceptibility of the isolates. Our finding confirms VRE colonization as risk factor of VRE BSI for AML patients. This finding is important for future patient education and development of preventive and treatment protocols.Disclosures All authors: No reported disclosures.