Enterococcus faecium is a Gram-positive

Gram-positive

Gram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain and appearing red or pink...

, alpha hemolytic or nonhemolytic bacterium in the genus Enterococcus

Enterococcus

Enterococcus is a genus of lactic acid bacteria of the phylum Firmicutes. Enterococci are Gram-positive cocci that often occur in pairs or short chains, and are difficult to distinguish from streptococci on physical characteristics alone. Two species are common commensal organisms in the...

. It can be commensal (innocuous, coexisting organism) in the human intestine, but it may also be pathogen

Pathogen

A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...

ic, causing diseases such as neonatal meningitis

Meningitis

Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...

.

Vancomycin-resistant E. faecium is often referred to as VRE

Vancomycin-Resistant Enterococcus

Vancomycin-resistant Enterococcus, or vancomycin-resistant enterococci , are bacterial strains of the genus Enterococcus that are resistant to the antibiotic vancomycin. To become VRE, vancomycin-sensitive enterococci typically obtain new DNA in the form of plasmids or transposons which encode...

.

Some strains of E. faecium are used as probiotic

Probiotic

Probiotics are live microorganisms thought to be beneficial to the host organism. According to the currently adopted definition by FAO/WHO, probiotics are: "Live microorganisms which when administered in adequate amounts confer a health benefit on the host"...

s in animals.

Treatment

Linezolid

Linezolid

Linezolid is a synthetic antibiotic used for the treatment of serious infections caused by Gram-positive bacteria that are resistant to several other antibiotics...

 or daptomycin

Daptomycin

Daptomycin is a novel lipopeptide antibiotic used in the treatment of certain infections caused by Gram-positive organisms. It is a naturally occurring compound found in the soil saprotroph Streptomyces roseosporus. Its distinct mechanism of action means that it may be useful in treating infections...

 are used to treat VRE infections. The streptogramins, such as quinupristin/dalfopristin

Quinupristin/dalfopristin

Quinupristin/dalfopristin is a combination of two antibiotics used to treat infections by staphylococci and by vancomycin-resistant Enterococcus faecium....

, may also be used for vancomycin-resistant E. faecium, but not E. faecalis.