E. faecalis

Enterococcus faecalis is a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. Like other species in the genus Enterococcus, E. faecalis is found in healthy humans, but can cause life-threatening infections, especially in the nosocomial (hospital) environment, where the naturally high levels of antibiotic resistance found in E. faecalis contribute to its pathogenicity. E. faecalis has been frequently found in reinfected, root canal-treated teeth in prevalence values ranging from 30% to 90% of the cases. E. faecalis is a nonmotile microbe. It ferments glucose without gas production, and does not produce a catalase reaction with hydrogen peroxide. Enterococci survive very harsh environments, including extremely alkaline pH (9.6) and salt concentrations. They resist bile salt s, detergent s, heavy metal s, 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.