Bacteria under Microscope

Enterococcus faecalis

	Gram-stain:	Gram-positive cocci
	Microscopic appearance:	Cocci in clusters, short chains, diplococci and single cocci
	Clinical significance:	Enterococcus faecalisis a Gram-positive, commensal bacterium inhabiting the gastrointestinal tracts of humans and other mammals. E. faecalis can cause life-threatening infections in humans, especially in the nosocomial (hospital) environment. Urinary tract infections (UTI) Bacteremia Endocarditis Meningitis E. faecalis is resistant to many commonly used antimicrobial agents. VRE (Vancomycin-Resistant Enterococcus)
		Text: Wikipedia
	Colony morphology:

	A		Non-hemolytic (gamma-hemolytic) colonies of Enterococcus faecalis on sheep blood agar. Cultivation 24 hours, aerobic atmosphere, 37°C.
	B		Enterococcus faecalis on Bile Esculin Agar (BEA). Members of the genus Enterococcus are capable of growing in the presence of 4% bile and hydrolyzing esculin to glucose and esculetin. Esculetin combines with ferric ions to produce a black complex visible as black zones around colonies. Cultivation 24 hours in an aerobic atmosphere, 37°C.
	C		Colonies of Enterococcus faecalis cultivated on Columbia agar with 5% defibrinated sheep blood, 24 hours in an aerobic atmosphere, 37°C. E.faecalis typically exhibits gamma-hemolysis on sheep's blood agar, but some strains are alfa-hemolytic or even beta-hemolytic (a plasmid-encoded hemolysin, called the cytolysin).