Quality control is performed to test the validity of catalase production at 68°C.M.fortuitum and M.tuberculosis are used,which yield a positive and negative reaction,respectively.Which one of the following statements explains this discrepancy?
A)Both organisms were most likely incubated at the wrong temperature.
B)Both organisms were most likely incubated on the wrong media before testing.
C)The catalase reagent is most likely expired.
D)No discrepancy is present.M.fortuitum is catalase-positive and M.tuberculosis is catalase-negative at 68°C.

Question

Quizplus · Accepted Answer

Because of the ability of the catalase enzyme to remain active after heating,a heat-stable catalase test that measures the heat stability of the enzyme is performed.When heated to 68°C for 20 minutes,the catalase of M.tuberculosis,M.bovis,Mycobacterium gastri,and M.haemophilum becomes inactivated.M.fortuitum remains positive.

Quality Control Is Performed to Test the Validity of Catalase