Source of S. Aureus ?

Kedar Korde ez065455 at boris.ucdavis.edu
Thu Jul 17 13:28:46 EST 1997

brendon (priceb at biochem.unp.ac.za) wrote:
: I would like to isolate protein A and phosphatidylinositol-specific
: phospholipase C from Staph. aureus and would like to know how easy it is to
: get hold of? I haven't had much experience with this organism [actually
: gram -ve coccus if my memory serves me] and would appreciate any input.
	If you want to isloate S. aureus yourself, it isn't really that
hard.  All you need to do is use a sterile cotton swab and swab regions of
your body (Side of the nose, behind the ear).  But to have a better chance
of get S. aureus (pathogen) as opposed to S. epidermis (common flora on
the skin), you should swab sores, usually pimples work the best.  Kinda
gross but that's where you find S. aureus.  Streak on YCG agar, and after
a day or two look for yellow golden colonies with rings around them
indicating fermentation.  
	Microscopy would show grape-shaped clusters.  Gram-staining would
show that these organisms are Gram +.  Fermentation, clustering, and G +
staining would indicate that you should restreak for purity.
	To differntiate between Streptococcus (Micrococcus has been
eliminated because these organisms are unable to ferment) use the enzyme
catalase test to indicate Staph.  Staph is able to break down hydrogen
peroxide to water and oxygen.  If you apply H2O2 to a colony of Staph,
bubbling will occur (use a glass slide).  Strep lacks this enzyme and
nothing will happen.
	Lastly, to see if you have S. aureus, you'll have to grow it on
phenol red mannitol.  If growth occurs on this slant, with a yellow color
change, you are pretty sure that you have S. aureus as opposed to S.

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