Staphylococcus

G+ cocci clusters

found as normal skin flora

catalase +

beta hemolytic

hemolysis

effect something has on red blood cells

3 types of hemolysis

alpha= part hemolysis (slight green color)

beta= complete hemolysis red cell bursts completely (white around colony)

gamma= no hemolysis (all red around colony)

Staphylococcus aureus

Gram + cocci clusters

common on skin

beta hemolytic

coagulase +

white or yellow colony

can cause acne, bed sores, sinusitis, ear infection

Staphylococcus aureus

virulence 7 factors

1. resists phagocytosis

2. lipase & proteinases these enzymes allow S.aureus to invade us

3. hyaluronidase breaks down glue that holds cell together & gets into our cells

4. leukocedin substance that destroyes pmns & monocytes (both carry out phagocytosis)

5. alpha, beta, gamma, delta toxins...All 4 cause beta hemolysis

6. Enterotoxins ABCD...

7. Exfoliation toxin=skin rash

8. Coagulase blood clotting

9. DNAse

Micrococcus

gamma hemolytic= no hemolysis

coagulase -

yellow colony

tetrads

no virulence

Streptococcus