Enterococcus faecalis

Gram Stain

• Gram positive cocci in pairs and short chains (aerobic)

Clinical Significance

This organism is part of commensal flora of gastrointestinal and female genitourinary tracts. It can be recovered from a variety of environmental sources (soil/water/plants/animals).

It is associated with endocarditis, intra-abdominal/pelvic infections, and urinary tract infections (commonly in persons with structural abnormalities or following urologic instrumentation).

It is an important cause of nosocomial infections, especially of the urinary tract.

Usual Susceptibility Pattern

This organism is usually susceptible to ampicillin, piperacillin/tazobactam, vancomycin and linezolid.

Ampicillin resistant strains are predictable resistant to piperacillin-tazobactam and imipenem. Ampicillin susceptibility does not necessarily predict susceptibility to piperacillin-tazobactam or imipenem. 

Imipenem is the only carbapenem with E. faecalis activity .

Ertapenem and meropenem are not active against E. faecalis.

Note: Ampicillin may exhibit diminished activity if the isolate is penicillin resistant. Close clinical follow-up recommended 

Ampicillin is preferred over penicillin (even if susceptible). It is resistant to cephalosporins (ceftriaxone ok in combination with ampicillin only), clindamycin, macrolides, fusidic acid, and TMP/SMX.

Ciprofloxacin has some activity against urinary isolates but increased resistance precludes empiric use.