Recurrent bacteremia with Enterococcus faecalis, the clinical findings predicting endocarditis, and genomic characterization of the isolates: a retrospective cohort study

Abstract

Multiple episodes of Enterococcus faecalis bacteremia (EfsB) may indicate a relapse and be due to an undiagnosed infective endocarditis (IE). The aims were to study the clinical presentation of patients with EfsB with focus on the risk of recurrent infection and IE, identify potential improvements of the management, and to investigate whether E. faecalis isolates from different episodes in the same patient were identical. In a retrospective study, a cohort of patients with monomicrobial (M) EfsB episodes was analyzed. Clinical data from medical records were collected. Furthermore, blood culture isolates from patients with multiple episodes were subjected to whole genome sequencing and multilocus sequence typing. In 666 episodes of MEfsB, 69 patients with IE and 43 with recurrent infections were found. Patients without IE, but with a following episode diagnosed as IE, were compared to those without a following episode. Variables significantly correlated with IE were long duration of symptoms, growth in all blood cultures, unknown origin of infection, heart murmur, and predisposition for IE. Transesophageal echocardiography, all negative, was done in 4 out of 11 episodes during the first episodes, later diagnosed with IE. In 28 of 31 patients with two or more EfsB episodes, isolates with identical sequence type were found. Episodes of EfsB in patients later diagnosed with IE showed features of IE already during the first episodes, were not adequately evaluated, are due to identical isolates, and most likely represent true relapses. Risk factor analysis should guide the use of echocardiography.

Keywords: Bacteremia; Endocarditis; Enterococcus faecalis; Recurrent infection; Sequence type; Whole genome sequencing.

Fig. 1

Schematic representation of the diagnoses of the episodes. Patients with different diagnoses in different episodes are indicated by arrows. The first column shows the diagnoses of all episodes preceding an EfsB including the PEfsB. The second column shows the diagnoses during the last episode in each patient. A single patient can have multiple preceding episodes and an episode can have more than one diagnosis, but why arithmetics are not fully applicable. The arrows indicate the different diagnoses in the episodes including the PEfsB. The width of the arrow indicates the number of patients, and numbers > 1 are shown adjacent to the arrow. Patients with the same diagnose in all episodes are not shown with arrows. The number of episodes in parenthesis in each box