Gram Positive Cocci
Staphyloccus aureus differs from staphylo-coccus epidermidis by (AIIMS Nov 2009)
|A||Is coagulase positive|
|B||Forms white colonies|
|C||A common cause ofUTI|
Coagulase test is the most important test for identification of S. aureus.
S.aureus forms golden yellow colonies which are beta hemolytic on blood agar. In contrast S.epidermidis is coagulase negative, forms white colonies which are non-hemolytic.
Tube coagulase is more confirmatory. S. lugdunensis is slide coagulase positive and 10-15% of S.aureus strains are slide coagulase negative.