تويت
Catalase test
purpose
this test used to differntiate thosebacteria that produce the enzyme catalase,such as staphylococci ,from non-catalase producing bacteria such as streptococci
principle
catalase act as catalyst in the breakdown of hydrogen peroxide to oxygen and water
bubbles of oxygen are released if the organism is catalase producer
this test used to differntiate thosebacteria that produce the enzyme catalase,such as staphylococci ,from non-catalase producing bacteria such as streptococci
principle
catalase act as catalyst in the breakdown of hydrogen peroxide to oxygen and water
bubbles of oxygen are released if the organism is catalase producer
impotant notes
- Care must be taken if testing an organism on a medium containing blood because catalase is present in red cells IF anthof the blood agar is removed with the colony,a false positive reaction will occure so catalas testing be performed from a blood free culture medium such as nutrient agar
2-) A nichrome wire loop must not be used because this may give afalse positive reaction
3-)the optimal pH of catalase is approximatly neutral but will varies by species
RESULTS
positive test---------------active bubbling
catalase produced
negative test-------------no release of bubbles
no catalase
تعليق