Enterococcus faecium

# Overview
Enterococcus faecium is a Gram-positive, alpha-hemolytic or nonhemolytic bacterium in the genus Enterococcus. It can be commensal (innocuous, coexisting organism) in the human intestine, but it may also be pathogenic, causing diseases such as neonatal meningitis or endocarditis.
Vancomycin-resistant E. faecium is often referred to as VRE.
Some strains of E. faecium are used as probiotics in both animals, and humans.

# Genome sequences
Genomes listed below are from the Integrated Microbial Genomes website.
The 22 sequenced Enterococcus faecium genomes

# Treatment

## Antimicrobial Regimen
- 1. Bacteremia
- 1.1 Ampicillin or penicillin susceptible
- Preferred regimen (1): Ampicillin 2 g IV q4-6h
- Preferred regimen (2): Ampicillin 2 g IV q4-6h AND Gentamicin 1 mg/kg IV/IM q8h
- 1.2 Ampicillin resistant and vancomycin susceptible or penicillin allergy
- Preferred regimen (1): Vancomycin 15 mg/kg IV q12h AND Gentamicin 1 mg/kg IV/IM q8h
- Preferred regimen (2): Linezolid 600 mg IV q12h
- Preferred regimen (3): Daptomycin 6 mg/kg IV q24h.
- 1.3 Ampicillin and vancomycin resistant
- Preferred regimen (1): Linezolid 600 mg IV q12h
- Preferred regimen (2): Daptomycin 6 mg/kg IV q24h
- 2. Endocarditis
- 2.1 Endocarditis in adults
- 2.1.1 Strains susceptible to penicillin, gentamicin, and vancomycin
- Preferred regimen: (Ampicillin 12 g IV q24h for 46 weeks OR Aqueous crystalline penicillin G sodium 1830 MU IV q24h for 46 weeks) AND Gentamicin sulfate 3 mg/kg IV/IM q24h for 46 weeks
- Alternative regimen: Vancomycin hydrochloride 30 mg/kg IV q24h for 6 weeks AND Gentamicin sulfate 3 mg/kg IV/IM q24h for 6 weeks
- Note (1): In case of native valve endocarditis with symptoms  3 months, a 4-week course of therapy is recommended.
- Note (2): In case of native valve endocarditis with symptoms > 3 months, a 6-week course of therapy is recommended.
- Note (3): In case of prosthetic valve or other prosthetic cardiac material, a minimum of 6-week course of therapy is recommended.
- 2.1.2 Strains susceptible to penicillin, streptomycin, and vancomycin and resistant to gentamicin
- Preferred regimen (1): (Ampicillin 12 g IV q24h for 46 weeks AND Streptomycin sulfate 15 mg/kg IV/IM q24h for 46 weeks
- Preferred regimen (2): Aqueous crystalline penicillin G sodium 24 MU/day IV q24h for 46 weeks AND Streptomycin sulfate 15 mg/kg IV/IM q24h for 46 weeks
- Alternative regimen: Vancomycin hydrochloride 30 mg/kg IV q24h for 6 weeks AND Streptomycin sulfate 15 mg/kg IV/IM q24h for 6 weeks
- 2.1.3 Strains resistant to penicillin and susceptible to aminoglycoside and vancomycin
- 2.1.3.1  Lactamaseproducing strain
- Preferred regimen: Ampicillin-sulbactam 12 g IV q24h for 6 weeks AND Gentamicin sulfate 3 mg/kg IV/IM q24h for 6 weeks
- Alternative regimen: Vancomycin hydrochloride 30 mg/kg IV q24h for 6 weeks AND Gentamicin sulfate 3 mg/kg IV/IM q24h for 6 weeks
- 2.1.3.2 Intrinsic penicillin resistance
- Preferred regimen: Vancomycin hydrochloride 30 mg/kg IV q24h for 6 weeks AND Gentamicin sulfate 3 mg/kg IV/IM q24h for 6 weeks
- 2.1.4 Strains resistant to penicillin, aminoglycoside, and vancomycin
- Preferred regimen (1): Linezolid 1200 mg IV/PO q24h  8 weeks
- Preferred regimen (2): Quinupristin-Dalfopristin 22.5 mg/kg IV q24h  8 weeks
- 2.2 Endocarditis in pediatrics
- 2.2.1 Strains susceptible to penicillin, gentamicin, and vancomycin
- Preferred regimen (1): Ampicillin 300 mg/kg IV q24h for 46 weeks AND Gentamicin 3 mg/kg IV/IM q24h 46 weeks
- Preferred regimen (2): Penicillin 0.3 MU/kg IV q24h for 46 weeks AND Gentamicin 3 mg/kg IV/IM q24h 46 weeks
- Alternative regimen: Vancomycin 40 mg/kg IV q24h for 6 weeks AND Gentamicin 3 mg/kg IV/IM q24h for 6 weeks
- Note (1): In case of native valve endocarditis with symptoms  3 months, a 4-week course of therapy is recommended.
- Note (2): In case of native valve endocarditis with symptoms > 3 months, a 6-week course of therapy is recommended.
- Note (3): In case of prosthetic valve or other prosthetic cardiac material, a minimum of 6-week course of therapy is recommended.
- 2.2.2 Strains Susceptible to penicillin, streptomycin, and vancomycin and resistant to gentamicin
- Preferred regimen (1): Ampicillin 300 mg/kg IV q24h for 46 weeks AND Streptomycin 2030 mg/kg IV/IM q24h for 46 weeks
- Preferred regimen (2): Penicillin 0.3 MU/kg IV q24h for 46 weeks AND Streptomycin 2030 mg/kg IV/IM q24h for 46 weeks
- Alternative regimen: Vancomycin hydrochloride 40 mg/kg IV q24h for 6 weeks AND Streptomycin sulfate 15 mg/kg IV/IM q24h for 6 weeks
- 2.2.3 Strains resistant to penicillin and susceptible to aminoglycoside and vancomycin
- 2.2.3.1  Lactamaseproducing strain
- Preferred regimen: Ampicillin-sulbactam 300 mg/kg IV q24h for 6 weeks AND Gentamicin 3 mg/kg IV/IM q24h for 6 weeks
- Alternative regimen: Vancomycin 40 mg/kg IV q24h for 6 weeks AND Gentamicin 3 mg/kg IV/IM q24h for 6 weeks
- 2.2.3.2 Intrinsic penicillin resistance
- Preferred regimen: Vancomycin 40 mg/kg IV q24h AND Gentamicin 3 mg/kg IV/IM q24h for 6 weeks
- 2.2.4 Strains resistant to penicillin, aminoglycoside, and vancomycin
- Preferred regimen (1): Linezolid 30 mg/kg IV/PO q24h  8 weeks
- Preferred regimen (2): Quinupristin-Dalfopristin 22.5 mg/kg IV q24h  8 weeks
- 3. Meningitis
- 3.1 Ampicillin susceptible
- Preferred regimen: Ampicillin 12 g/day IV q4h AND Gentamicin 5 mg/kg/day IV q8h
- 3.2 Ampicillin resistant
- Preferred regimen: Vancomycin 3045 mg/kg/day IV q812h AND Gentamicin 5 mg/kg/day IV q8h
- 3.3 Ampicillin and vancomycin resistant
- Preferred regimen: Linezolid 600 mg IV q12h
- 4. Urinary tract infections
- Preferred regimen (1): Nitrofurantoin 100 mg PO q6h for 5 days
- Preferred regimen (2): Fosfomycin 3 g PO single dose
- Preferred regimen (3): Amoxicillin 875 mg to 1 g PO q12h for 5 days
- 5. Intra abdominal or wound infections 
- Preferred regimen (1): Penicillin
- Preferred regimen (2): Ampicillin
- Alternative regimen (penicillin allergy or high-level penicillin resistance): Vancomycin
- Alternative regimen (for complicated skin-skin structure and intra-abdominal infection): Tigecycline 100 mg IV single dose and 50 mg IV q12h