Enterococcal Bacteremia
- Enterococcal bacteremia (EB) is a common issue in the healthcare setting and often complicated by endocarditis (IE)
- Commonly affects elderly, fragile, immunosuppressed patients
- High mortality rates (up to 20%) that is influenced by appropriate antibiotic therapy
- No clear consensus guideline on EB treatment
Workup
Microbiology
- Faecalis causes over 90% of enterococcal IE cases and more commonly associated with GU abnormalities.
- Faecium more commonly associated with GI source and catheters, polymicrobial bacteremia, previous broad spectrum abx, transplant, and cirrhosis
- Susceptibility testing needs to include vancomycin, ampicillin, gentamicin. If VRE, then also linezolid and daptomycin.
Determination of Focus
- Careful patient interviewing and thorough physical examination are the basic tools to investigate the infection source. Culture positivity should be assessed together with appropriate clinical assessment of signs and symptoms. Differential time to positivity is especially useful to diagnose catheter-related EB.
- A notable proportion of EB episodes make up part of polymicrobial bacteraemia, frequently associated with an abdominal focus.
Assessing for Complications
- clinical examination
- echocardiography -- see Echocardiograms in Bloodstream Infections as well
- E faecalis - indicated for stroke or relapsing bacteremia, high risk per Duke's, and if cannot rule out with NOVA or DENOVA scores.
- E faecium - rates of IE are very low --> assess the clinical picture and restrict echocardiography to cases with a high suspicion of IE
- consider PET-CT if available for ?prosthetic and graft infections
- consider colonoscopy due to the high incidence of CRC in these patients
Treatment
Antibiotic Choice
This depends highly on whether you are treating E faecalis or faecium. The cornerstone of treatment is ampicillin but most faecium have high-level PCN resistance meaning the risk of treatment failure is high with these pathogens.
Enterococcus is also intrinsically resistant to aminoglycosides (lack of cell wall permeability), but aminoglycosides are synergistic with cell-wall-acting antibiotics such as beta-lactams.
| E faecalis | E faecium | VRE | ||
|---|---|---|---|---|
| Uncomplicated bacteremia | Ampicillin, piperacillin, vancomycin, daptomycin, linezolid | Vancomycin, daptomycin, linezolid | Linezolid or daptomycin +/- beta-lactam | |
| Endocarditis | Amp+CTX or amp/PCN + gentamicin | Vancomycin + gentamicin | Daptomycin or linezolid +/- gentamicin or beta-lactam |
Summary:
- uncomplicated EB --> ampicillin or vancomycin monotherapy
- E faecalis endocarditis --> amp + gentamicin or amp + ceftriaxone (similar outcomes)\
- VRE --> linezolid or daptomycin
Antibiotic Duration
| Situation | Duration |
|---|---|
| Uncomplicated EB | 7-14 days |
| VRE bacteremia | 2 weeks after clearance of blood cultures |
| Complicated EB (other than IE) | 4+ weeks |
| E faecalis IE | 6 weeks (amp+CTX or amp+gent+prosthetic valve) or 4 weeks (amp+gent+native valve) |
References
- Beganovic, Maya, Megan K Luther, Louis B Rice, Cesar A Arias, Michael J Rybak, and Kerry L LaPlante. “A Review of Combination Antimicrobial Therapy for Enterococcus Faecalis Bloodstream Infections and Infective Endocarditis.” Clinical Infectious Diseases 67, no. 2 (July 2, 2018): 303–9. https://doi.org/10.1093/cid/ciy064.
- Turco, Elena Rosselli Del, Michele Bartoletti, Anders Dahl, Carlos Cervera, and Juan M. Pericàs. “How Do I Manage a Patient with Enterococcal Bacteraemia?” Clinical Microbiology and Infection 27, no. 3 (March 1, 2021): 364–71. https://doi.org/10.1016/j.cmi.2020.10.029.