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. They look like streptococci. Two species are regular gut flora organisms in the intestines of humans: "E. faecalis" (90-95%) and "E. faecium" (5-10%).
Physiology and classification.
Enterococci are "facultative anaerobic organisms". This means they can live in both oxygen-rich and oxygen-poor environments.
Members of the genus "Enterococcus" were classified as Group D "Streptococcus" until 1984. Genomic DNA analysis showed they were a separate genus.
Pathology.
Important infections caused by "Enterococcus" include urinary tract infections, bacterial endocarditis, diverticulitis, and meningitis.
Sensitive strains of these bacteria can be treated with ampicillin, penicillin and vancomycin. Urinary tract infections can be treated by antibiotics, but many virulent strains of "Enterococcus" are resistant. From a medical standpoint, an important feature of this genus is the high level of antibiotic resistance. This rules out some important antibiotics.