Antibiotic therapy for Enterococcus bacteraemia: warning for the antimicrobial stewardship team.

Abstract

Enterococci are a significant cause of bacteraemia in healthcare-associated infections (HCAI), being resistant to cephalosporins and aminoglycosides often used in this setting. Our aim was to measure the rate of inefficient antimicrobial therapy and its impact on the outcome. We conducted a retrospective multicentre cohort study in 6 French institutions. Patients were identified through the laboratory's database, which extracted all positive blood cultures for Enterococcus spp. in 2016. Patients' data were gathered by reviewing hospital records. Efficient antimicrobial therapy was defined as any therapy containing at least one antibiotic compound with in vitro efficacy against Enterococcus spp.: amoxicillin, amoxicillin/clavulanic acid, piperacillin, piperacillin/tazobactam, imipenem, meropenem, vancomycin, daptomycin, linezolide, tigecycline. A short-term unfavourable outcome was defined as intensive care requirement and/or in-hospital death at least 48h after positive blood culture. One hundred thirty-one patients were included; the main diagnosis was a urinary tract infection (46%) and a HCAI was observed in 54% of the cases. Four patients did not receive any antibiotic. Forty-three per cent of empirical antibiotic therapies and 17% of documented ones were inefficient for enterococcal bacteraemia. Sixty patients (46%) received amoxicillin as a documented therapy. Twenty-three per cent of the patients presented a short-term unfavourable outcome. Univariate and multivariate analyses showed that not receiving amoxicillin as a documented antibiotic therapy was associated with an unfavourable short-term outcome (p = 0.001). In conclusion, Enterococcal bacteraemia was associated with a high proportion of inefficient antimicrobial therapy. In multivariate analysis, amoxicillin use was associated with a better outcome.