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.<ref name=Baron>{ { cite book | author = Pelletier LL Jr. | title = Microbiology of the circulatory system. in: Baron S et al. (eds) Baron's Medical Microbiology. | edition = 4th | publisher = Univ of Texas Medical Branch | year = 1996 | url = https://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mmed.section.5077 | isbn = 0-9631172-1-1 }}</ref> 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 intrinsic antibiotic resistance. This rules out some important antibiotics.