Risk factors and outcomes associated with non-Enterococcus faecalis, non-Enterococcus faecium enterococcal bacteremia

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Epidemiology

Background:

• Enterococcus species are significant causes of hospital-acquired infections.
• Enterococcus faecalis and Enterococcus faecium are the most common species causing enterococcal bacteremia.
• Limited data exist on the clinical characteristics and outcomes of bacteremia caused by other Enterococcus species.

Purpose of the Study:

• To compare risk factors, clinical features, and outcomes of bacteremia caused by specific non-E. faecalis, non-E. faecium Enterococcus species (E. avium, E. casseliflavus, E. durans, E. gallinarum, E. mundtii) with those of E. faecalis bacteremia.

Main Methods:

• Retrospective case-control study conducted at a university-affiliated academic medical center.
• Identified 33 cases of bacteremia due to E. avium, E. casseliflavus, E. durans, E. gallinarum, or E. mundtii.
• Matched each case with one control with E. faecalis bacteremia based on admission date.

Main Results:

• Cases (non-E. faecalis, non-E. faecium) had a significantly longer mean hospital stay (29.7 vs. 17.2 days) and time to bacteremia acquisition (16.5 vs. 6.3 days).
• Cases were more likely to have underlying hematologic malignancies, prior corticosteroid treatment, neutropenia, gastrointestinal tract source of infection, and concurrent cholangitis.
• Controls were more likely to have an indwelling bladder catheter; no differences in severity of illness or mortality rates were observed.

Conclusions:

• Patients with bacteremia due to non-E. faecalis, non-E. faecium Enterococcus species exhibit distinct risk factors including hematologic malignancy, corticosteroid use, neutropenia, and cholangitis.
• These infections are associated with a prolonged hospital stay but do not appear to increase mortality risk compared to E. faecalis bacteremia.
• Understanding these differences is crucial for targeted management and infection control strategies in enterococcal bacteremia.