intrinsically resistant VRE component. This results in increased resistant group D enterococci,
i.e., VRE in hospitals. However, this does not represent an increase in group D enterococcal
resistance, but rather indicates an increase in the prevalence of intrinsically more resistant
VSE.
As mentioned previously, VSE are usually susceptible to vancomycin as well as
ampicillin. In contrast, VRE isolates are uniformly resistant to vancomycin and ampicillin.
Relatively few antibiotics have anti-VRE activity. Antibiotics useful to treat serious systemic
infections due to VRE include quinupristin/dalfopristin, linezolid, daptomycin, tigecycline,
chloramphenicol, and minocycline. For VRE CAB or cystitis, nitrofurantoin is useful. For VRE
endocarditis, which is rare, preferably a bactericidal anti-VRE drug should be used, i.e.,
quinupristin/dalfopristin (1,15) (Table 2).
The route of administration of the antibiotic depends on the severity of the infection and
gastrointestinal absorption. In general, all non-critically ill patients capable of gastrointestinal
absorption may be treated equally. The duration of treatment for VRE infections depends on
location. VRE CAB does not require treatment in normal hosts. In compromised hosts, after
urinary catheter change/removal, one week of therapy is usually sufficient.
If SBE is not present, the treatment of VRE CVC infections after IV line removal is for two
weeks. Such patients must be followed to be sure that VRE bacteremia from the CVC line
infection does not result in infective endocarditis (10–13). Serial blood cultures and
echocardiography will differentiate VRE bacteremia from VRE endocarditis. The duration of
therapy for VRE endocarditis depends on the duration of symptoms prior to clinical
presentation. Patients with a history of3 months of symptoms are treated for 4 weeks and
those with>3 months are treated for 6 weeks preferably with a bactericidal anti-VRE antibiotic
(1,16–20).
Table 1 Enterococcal Bacteremia: Diagnostic and Therapeutic Approach
Diagnostic approach:
l Differentiate enterococcal blood culture positivity (1/4–1/2 positive blood cultures) from bacteremia
l Consider the source of enterococcal bacteremia
Intra-abdominal/pelvic infection
Urinary tract infection
Endocarditis
l Determine the source of enterococcal bacteremia
8 Urinary tract source
Urine analysis/culture
8 Abdominal/pelvic source
Abdominal/pelvic CT scan to diagnose or r/o abdominal/pelvic abscesses, cholecystitis, or diverticulitis
Abdominal/pelvic CT scan to diagnose or r/o renal obstruction, stones, intrarenal/perinephric abscesses
8 Cardiac source
TTE/TEE to diagnose or r/o endocarditis
Therapeutic approach:
l Empiric therapy of VSE
8 Non-penicillin-allergic patients
Ampicillin
8 Penicillin-allergic patients
Vancomycin
Linezolid
Daptomycin
Tigecycline
l Empiric therapy of VRE
8 Penicillin- and non-penicillin-allergic patients
Linezolid
Daptomycin
Quinupristin/dalfopristin
TigecyclineSource: Adapted “Diagnostic approach” from Ref. 26 and “Therapeutic approach” from Ref. 13.
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