Background The incidence of Enterococcus faecium infections has increased over the past years and is currently the third major microorganism implicated in nosocomial bacteraemia. Nevertheless, the best treatment available is yet to be established, especially in vancomycin-susceptible E. faecium. In this setting, a correct dosage is essential, as inappropriate dosage has been associated with a higher risk of treatment failure.

Purpose Our objective was to describe the dosage adequacy of antibiotics used in the treatment of E. faecium bacteraemia.

Material and methods Retrospective observational study performed in a 400-bed university teaching hospital from June 2011 to June 2016. Patients with E. faecium isolation from at least one positive blood culture were included. Dosage adequacy was assessed by infectious-diseases-trained pharmacists, who reviewed antimicrobial prescriptions daily and recommended an appropriate dose adjustment in the first 24 to 72 hours of treatment. Inappropriate dosage was considered if it was out of therapeutic range according to plasmatic levels when available, or if an adjustment was needed according to weight or renal function (based on John Hopkins antibiotic guide and data sheet). Categorical variables were presented as percentages and continuous variables as mean (±SD).

Seventy patients were included Sixty (85.7%) males, 17 (24.3%) critically ill, mean age 69.8 (±13.5) years. Thirty (42.3%) patients received an inappropriate dosage, 19 (63.3%) of them were underdosed.

Conclusion Almost 43% of patients were inappropriately dosed in E. faecium bacteraemia, mainly because of underdosing. These data demonstrate the large proportion of inappropriate doses, which highlights the importance of an adequate review of medication and therapeutic drug monitoring in order to assure efficacy and prevent toxicities.

No conflict of interest