Bacteria Genomes - ENTEROCOCCUS FAECALIS

Enterococcus faecalis is a Gram-positive , facultatively anaerobic, cocci which occurs singly, in pairs or short chains. It is a normal inhabitant of the intestinal tract and female genital tract.

Scientists have identified a virulence region never seen before in the genome of Enterococcus faecalis - a leading cause of bacterial infection among hospital patients. This bacterium lives peacefully in the human gut, but it also thrives on wounds and burns. Researchers have identified a group of genes that may contribute to the bacterium's transformation from being harmless in the gut to a menacing invader. There has long been concern about the dangers of antibiotic resistance and its implications for the return of infectious diseases that cannot be effectively treated. It is argued that hospitals are not only spreading bacteria from patient to patient, but are also harbouring a tougher breed of bug-one that is resistant to antibiotics.

The sequencing of the genome reinforces knowledge of the remarkable fluidity of the bacterial gene pool. This fluidity allows bacteria to exchange DNA to enhance their ability to cause disease or their resistance to antibiotics.

Generally these microbes live harmlessly in the intestine however until the entire genome was sequenced, scientists did not realise that a quarter of enterococcus' genome is made-up of mobile DNA and within these regions are genes for vancomycin resistance and for virulence. Vancomycin is the last-resort antibiotic in fighting infection.

Enterococcus faecalis is extremely hardy and can survive for weeks on environmental surfaces; cheese - 180 days; soil up to 77 days; soiled linen up to 90 days, cultures at -70 C for several years.

References:

Science 2003, 299 (5615):2071-4
http://www.hc-sc.gc.ca/pphb-dgspsp/msds-ftss/msds146e.html
http://gnn.tigr.org/articles/04_03/killers_rev.shtml