Coagulase and Clumping Factor Test

Coagulase test In a diagnostics lab, what would happen if you incubated the tubes too long?

Coagulase test In a diagnostics lab performing the coagulase test, if the tubes of rabbit plasma treated with EDTA and organism were incubated for *too long*, coagulation would have already taken place and been *broken down* by the time you were able to view the tubes, and this would indicate a false (-)

Coagulase test What is the rabbit plasma treated with that interrupts the normal clotting mechanism?

Coagulase test The *rabbit plasma* in the coagulase test is treated with *EDTA*, an anticoagulant used to prevent a false (-)

Coagulase test What is the substrate used?

Coagulase test The *substrate* for the coagulase test is *rabbit plasma*

Coagulase test When you observe a (+) result (clumping of cells), what is the interpretation

Coagulase test The interpretation of a clumping of cells (a positive result) of the coagulase test means that the *plasma has been coagulated by bound coagulase* (the clumping factor)

Coagulase test What happens when free/bound coagulase reacts with plasma fibrinogen?

Coagulase test When free/bound coagulase reacts with plasma fibrinogen, the *precipitated fibrin links to cells* to produce *visible clumps*

Coagulase test What is the resistance of Staphylococcus aureus to the normal immune response and antimicrobial agents due to ?

Coagulase test Resistance of Staphylococcus aureus due to the production of the *coagulase enzyme*

Coagulase test What is the reaction/process that takes place for the coagulase test?

Coagulase test Rxn/process= Coagulation

Coagulase test What does the coagulase test differentiate?

Coagulase test Differentiates Staphylococcus aureus from other gram (+) cocci

Coagulase test What is the end product of interest?

Coagulase test *End product of interest* for the *coagulase test*= fibrin clot/clump

Coagulase test What does a (+) result look like?

Coagulase test (+) result for the coagulase test= medium is *solid* within 24 hours, this means the *plasma has been coagulated* by free or bound coagulase. *Presumptive ID= Staphylococcus aureus*

Coagulase test What does a (-) test look like?

Coagulase test (-) result= medium remains liquid after 24 hours, this means the plasma has *not* been coagulated. *Presumptive ID= NOT Staphylococcus aureus*

Coagulase test How does coagulase enzyme work?

Coagulase test Coagulase enzyme works in conjunction with normal *plasma* components to create *protective fibrin barriers* around individual bacterial cells/groups of cells *to shield them from phagocytosis* and other types of attack

Coagulase test What is the enzyme of the coagulase test?

Coagulase test Enzyme for the coagulase test is *coagulase*

Coagulase test What would happen if *EDTA* was removed from the rabbit plasma

Coagulase test If EDTA was removed from the rabbit plasma of the coagulase test, you would get a false (-)