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The Gram-positive species Enterococcus faecalis commonly inhabits the mammalian intestine, where it belongs to the predominant flora immediately after birth and remains present in considerable amounts during all life. However, it can also grow in other habitats such as plant surfaces or diary products and survive even heavy stress conditions during a prolonged period of time. The latter fact contributes to the increasing incidence of E. faecalis in nosocomial infections of, e.g., the urinary tract, endocardium, or blood. The high intrinsic resistance to high temperatures (62 °C), desiccation, high osmolarity (9 % NaCl), low pH (3.2), ultraviolet irradiation, oxigen radicals (20 mM H2O2, 0.05 % NaOCl), ethanol (17 %), etc. 1, promotes the rapid spread of clinical strains within hospitals. A second feature of E. faecalis important in this context is the frequency of mobile genetic elements such as conjugative plasmids or transposons, which readily transfer between E. faecalis strains and even to other species. Therefore, E. faecalis is considered as a central ‘gene pool’ for the interspecific transfer of antibiotic resistances among bacteria of the digestive tract2. Some strains of E. faecalis, similarly to Staphylococcus aureus, are meanwhile resistant to most of the therapeutically relevant antibiotics including vancomycin. |
