Differentiating gram positive cocci

Hello awesomites!

Today, let's see how can we differentiate between Staphylococci and Streptococci!

We can differentiate gram positive cocci morphologically - Staphylococci are in grape like clusters, Streptococci are present in chains.

Although sometimes, it might be difficult to do this. We can do biochemical tests to be sure (And they are easier to do than looking into a microscope!)

We can simply rule out streptococci by using catalase test as only staphylococci are catalase positive.

How do you differentiate between Staphylococcus aureus and other Staphylococci?

Well, Staphylococcus aureus is coagulase positive and other species of staphylococci are coagulase negative. (IkaN remembers it as "Aureus is Glorious" coag-Glorious? xD)

We can also use phosphatase test for the same: S. Aureus is phosphatase positive and others are negative.

How is S. Saprophyticus  differentiated from S. Epidermidis and S. Hemolyticus?

S. saprophyticus can be differentiated from others by Novobiocin test.

(Mnemonic here - Antibiotic sensitivity tests for gram positive cocci mnemonic http://www.medicowesome.com/2013/06/antibiotic-sensitivity-tests-for-gram.html)

How do we differentiate different types of streptococci?
On the basis of their hemolysis patterns!
(Mnemonic here: Alpha and Beta hemolytic organisms mnemonic http://www.medicowesome.com/2014/03/alpha-and-beta-hemolytic-organisms.html)

~Ojas