Bacteria under Microscope

Staphylococcus epidermidis

	Gram-stain:	Gram-positive
	Microscopic appearance:	Cocci in grape-like clusters, diplococci, cocci
	Clinical significance:	Staphylococcus epidermidis is part of human skin flora (commensal). It can also be found in the mucous membranes and in animals. S. epidermidis is not usually pathogenic but patients with compromised immune systems are often at risk for developing an infection. These infections can be both nosocomial or community acquired. The ability to form biofilms on plastic devices is a major virulence factor for S. epidermidis. S. epidermidis strains are often resistant to antibiotics. S. epidermidis causes biofilms to grow on plastic devices placed within the body (intravenous catheters, medical prostheses...). Endocarditis Sepsis (hospital patients)
		Text: Wikipedia
	Colony morphology:

	A		Colonies of Staphylococcus epidermidis on sheep blood agar. Cultivation 24 hours, aerobic atmosphere, 37°C.
	B		Gamma-hemolytic (non-hemolytic) colonies of Staphylococcus epidermidis on sheep blood agar. Cultivation 24 hours in an aerobic atmosphere, 37°C.
	C		Staphylococcus epidermidis on mannitol salt agar, 24 hours in an aerobic atmosphere, 37°C. Natrium chloride (7.5%) tolerant, mannitol negative (compare with S.aureus on the same medium: NaCl tolerant, mannitol positive (yellow) colonies).