Daptomycin Susceptible versus Nonsusceptible Enterococcus faecium Bacteremias: Comparison of Clinical and Microbiological Outcomes
Daptomycin nonsusceptibility is reportedly emerging in all targeted gram-positive pathogens including Enterococcus faecium. Reported rates of daptomycin nonsusceptible E. faecium (DNSEF) isolates have ranged from 0.6% to 19.1%. Currently, there is limited data regarding the management and outcomes of daptomycin nonsusceptible enterococcal infections. The objective of this study is to expand current knowledge and to compare clinical and microbiological outcomes between patients with daptomycin susceptible E. faecium (DSEF) and DNSEF bacteremias.
A microbiology report of patients with positive blood cultures for Enterococcus species between September 2008 and October 2013 was generated. Electronic medical records were reviewed and data was collected from patients meeting the selection criteria. Patients of at least 18 years of age with blood cultures positive for E. faecium were eligible for inclusion. Identification and susceptibility testing was performed by the hospital laboratory using an automated microbiology system (Microscan Walkway®). Primary endpoints included clinical and microbiologic response rates. Secondary endpoints included hospital length of stay and 30-day mortality from index culture, and in-hospital mortality.
Overall, 60 patients were evaluated; 35 were included in the DSEF group and 25 were included in the DNSEF group. In the evaluable patients, microbiological clearance was observed in 27 of 27 (100%) for the DSEF group and 21 of 21 (100%) in the DNSEF group (p=1.00). Clinical cure was observed in 25 of 35 (71.4%) and 14 of 25 (56%) patients in the DSEF and DNSEF groups, respectively (p= 0.28). Median length of stay from the index culture in the DSEF and DNSEF groups were 11.7 and 12.4 days respectively (p=0.78). As compared to DSEF bacteremias, DNSEF bacteremias had higher rates of 30-day mortality (44.0% vs 31.4%, p=0.42) and overall in-hospital mortality (52.0% vs 34.2%, p=0.19).
Bacteremias caused by DNSEF may be associated with worse clinical outcomes, including lower rates of clinical cure and higher rates of mortality.
T. Abraham, None
N. Saad, None
N. Goldshteyn, None
R. Andrescavage, None