Enterococcus faecalis is normally present in colonic flora therefore are catalase negative. Commonly infections with this organism cause UTI, endocarditis, or biliary tree infections. Look for a history of GI/GU surgery or previously damaged heart valves. They appear as gram positive cocci in chains. Identification is based on its variable hemolysis (gamma) , PYR positivity, and ability to hydrolyze esculin in bile and NaCl (black color).