Enterococcus faecalis is a gram positive, catalase negative bacteria that is an increasing worry for clinicians as a cause of hospital-acquired infections.
It is a normally occurring bacteria in the intestines, bile ducts, and genitourinary system. However, when there is local overgrowth due to other flora being suppressed (especially by cephalosporins) it causes clinically important urinary and biliary tract infections.
Interestingly, Enterococcus faecalis has an outer capsule that prevents it from being degraded by bile salts.
Of particular worry is the ability of Enterococcus faecalis to enter the bloodstrean and colonize heart valves in subacute bacterial endocarditis.
There is a heightened risk of subacute bacterial endocarditis in heart valves that have previously been damaged by Group A streptococcus such as in rheumatic fever.
All strains of E. faecalis are resistant to cephalosporins and there are now some strains resistant to vancomycin.
The diagnosis is made by culturing in 40% bile and 6.5% sodium chloride solution.
Treatment most commonly is ampicillin or vancomycin if no resistance is present and an aminoglycoside