Enterococcus faecalis

Enterococcus faecalis. Photo by:Pete Wardell / CDC

Classification

Higher order taxa

Bacteria; Firmicutes; Bacilli; Lactobacillales; Enterococcaceae; Enterococcus

Genus

Enterococcus faecalis

Description and significance

Enterococcus are gram-positive cocci that can survive harsh conditions in nature. They can be found in soil, water, and plants. Some strains are used for the manufacture of foods whereas others are the cause of serious human and animal infections (i.e. they are known to colonize the gastrointestinal and gential tracts of humans). They are associated with both community and hospitial acquired infections. Enterocci can grow at a temperature range of 10 to 42°C and in environments with broad pH values. Some are known to be motile.While there are over 15 species of the Enterococcus genus, 80-90% of clinical isolates are E. faecalis. Enterocci typically form short chains or are arranged in pairs. However, under certain growth conditions, they elongate and appear coocobacillary. In general, enterococci are alpha-hemlytic. Some possess the group D Lancefield antigen and can be detected using monoclonal antibody-based agglutination tests. Enterococci are typically catalase negative, and are anaerobic. They are able to grow in 6.5% NaCl, can hydrolyze esculin in the presence of 40% bile salts and are pyrrolidonyl arylamidase and leucine arylamidase positive. Enterococci have proven to present a therapeutic challenge because of their resistance to many antimicrobial drugs, including cell-wall active agents, aminoglycosides, penicillin and ampicillin, and vancomycin. In the last decade, vancomycin-resistnat enerococci have become a major challenge. The enterococci have the capacity to acquire a wide variety if antimicrobial resistance factors which present serious problems in the management of patients with enteroccoal infections. In general, entercoccal isolates with lowered susceptibility to vancomycin can be categorized as vanA, vanB, and vanC. vanA and vanB pose the greatest threat because they are the most resistant and the resistance genes are carried on a plasmid. Since the resistance genes are carried on a plasmid they readily transferable. E. faecalis strains are categorized as vanA isolates. E. faecalis are also resistant to teicoplanin. Enterococcal strains that are vancomycin dependent have been reported, but are rare and are less common that vancomycin-resistant strains.

Genome structure

Describe the size and content of the genome. How many chromosomes? Circular or linear? Other interesting features? What is known about its sequence? Does it have any plasmids? Are they important to the organism's lifestyle?

Cell structure and metabolism

Describe any interesting features and/or cell structures; how it gains energy; what important molecules it produces.

Ecology

Describe any interactions with other organisms (included eukaryotes), contributions to the environment, effect on environment, etc.

Pathology

How does this organism cause disease? Human, animal, plant hosts? Virulence factors, as well as patient symptoms.

Application to Biotechnology

Does this organism produce any useful compounds or enzymes? What are they and how are they used?

Current Research

Enter summaries of the most recent research here--at least three required

References

Murrary BE. 1998. "Diversity among the multidrug-resistant “enterococci”. Emerging Infectious Diseases, vol. 4, no. 1. (46-65)

De la Maza, Luis M., Marie T. Pezzlo, and Janet T. Shigei. Color Atlas of Medical Bacteriology. Washington, DC: American Society for Microbiology, 2004.

De Boever EH,Clewell DB, Fraser CM. 2000. "Enterococcus faecalis conjugative plasmid pAM373: complete nucleotide sequence and genetic analyses of sex pheromone response." Molecular Microbiology, vol. 37, no. 6. (1327-1341)

Glockner, F. O., M. Kube, M. Bauer, H. Teeling, T. Lombardot, W. Ludwig, D. Gade, A. Beck, K Borzym, K Heitmann, R. Rabus, H. Schlesner, R. Amann, and R. Reinhardt. 2003. "Complete genome sequence of the marine planctomycete Pirellula sp. strain 1." Proceedings of the National Acedemy of Sciences, vol. 100, no. 14. (8298-8303)

Edited by Richard A. Martinez of UC San Diego, student of Rachel Larsen.