Enterococcus faecalis

E. faecalis is a nonmotile microbe; it ferments glucose without gas production, and does not produce a catalase reaction with hydrogen peroxide. It produces a reduction of litmus milk, but does not liquefy gelatin. It shows consistent growth throughout nutrient broth which is consistent with being a facultative anaerobe. It catabolizes a variety of energy sources, including glycerol, lactate, malate, citrate, arginine, agmatine, and many keto acids. Enterococci survive very harsh environments, including extremely alkaline pH (9.6) and salt concentrations. They resist bile salts, detergents, heavy metals, ethanol, azide, and desiccation. They can grow in the range of 10 to 45 °C and survive at temperatures of 60 °C for 30 min.[4]

E. faecalis is found in most healthy individuals, but can cause endocarditis and sepsis, urinary tract infections (UTIs), meningitis, and other infections in humans.[5][6] Several virulence factors are thought to contribute to E. faecalis infections. A plasmid-encoded hemolysin, called the cytolysin, is important for pathogenesis in animal models of infection, and the cytolysin in combination with high-level gentamicin resistance is associated with a five-fold increase in risk of death in human bacteremia patients.[7][8][9] A plasmid-encoded adhesin[10] called "aggregation substance" is also important for virulence in animal models of infection.[8][11]

This is a Gram stain for Enterococcus faecalis under 1000 magnification (bright field microscopy)

• Endures prolonged periods of nutritional deprivation
• Binds to dentin and proficiently spreads into dentinal tubules via chain propagation
• Alters host responses
• Suppresses the action of lymphocytes
• Possesses lytic enzymes, cytolysin, aggregation substance, pheromones, and lipoteichoic acid
• Utilizes serum as a nutritional source
• Produces extracellular superoxide under selected growth conditions that can generate chromosomal instability in mammalian cells[18][19]
• Resists intracanal medicaments (e.g. calcium hydroxide), although a study proposes elimination from root canals after using a mixture of a tetracycline isomer, an acid, and a detergent[20]
  • Maintains pH homeostasis
  • Properties of dentin lessen the effect of calcium hydroxide
• Competes with other cells
• Forms a biofilm[4]
• Activates the host protease plasminogen in a fashion that increases local tissue destruction[21]

Prior to 1984, enterococci were members of the genus Streptococcus; thus, E. faecalis was known as Streptococcus faecalis.[22]

In 2013, a combination of cold denaturation and NMR spectroscopy was used to show detailed insights into the unfolding of the E. faecalis homodimeric repressor protein CylR2.[23]

The E. faecalis genome consists of 3.22 million base pairs with 3,113 protein-coding genes.[24]

Bacterial small RNAs play important roles in many cellular processes; 11 small RNAs have been experimentally characterised in E. faecalis V583 and detected in various growth phases.[25] Five of them have been shown to be involved in stress response and virulence.[26]

A genome-wide sRNA study suggested that some sRNAs are linked to the antibiotic resistance and stress response in another Enteroccocus: E. faecium.[27]

• Anti-Q RNA

Wikimedia Commons has media related to Enterococcus faecalis.

• Type strain of Enterococcus faecalis at BacDive – the Bacterial Diversity Metadatabase