Enterococcal bacteraemia: predictive and prognostic risk factors for ampicillin resistance

Abstract

AbstractTo identify the predictive and prognostic factors associated with ampicillin-resistant enterococcal bacteraemia, we retrospectively reviewed demographic, microbiological and clinical data of patients attending the Kyoto University Hospital, Japan, between 2009 and 2015. Logistic regression and Cox regression analyses were performed to determine the predictive and prognostic factors, respectively. In total, 235 episodes of enterococcal bacteraemia were identified. As ampicillin susceptibility was uniform forEnterococcus faecalisisolates and almost all ampicillin-resistant isolates wereE. faecium, bacteraemia due to these species was investigated separately.E. faecalisandE. faeciumaccounted for 41.7% (98/235) and 48.1% (113/235) of the isolates, respectively and 91.2% of allE. faeciumwere ampicillin resistant. NosocomialE. faeciumbacteraemia acquisition (odds ratio (OR), 13.6; 95% confidence intervals, 3.16–58.3) was associated with ampicillin-resistant isolates. Bacteraemia from an unknown source (hazard ratio (HR), 2.91; 95% CI 1.36–6.21) and an increased Pitt bacteraemia score (PBS) (HR, 1.36; 95% CI 1.21–1.52) were associated with 30-day mortality inE. faeciuminfections. Likewise, bacteraemia from an unknown source (HR, 4.17; 95% CI 1.25–13.9) and increased PBS (HR, 1.27; 95% CI 1.09–1.48) were associated with 30-day mortality in patients withE. faecalisbacteraemia. The empirical therapeutic administration of glycopeptides is recommended for patients with bacteraemia from an unknown source in whom severeE. faeciumbacteraemia is suspected.