Results of catalase tests using two Gram positive cocci
Bacterial species
Bubbling
Catalase Test (Positive/Negative)
1
Streptococcus pyogenes
2
Staphylococcus aureus
Critical Thinking Questions:
1. What is the purpose of the catalase test?
2. What kind of bacteria produce catalase?
3. Why does a bacterium produce catalase?
4. What are the bubbles observed in a positive reaction?
5. If a bacterial strain is catalase positive, is it always an obligate (strict) aerobe? Explain.
6. If a bacterial strain is catalase negative, is it always an obligate (strict) anaerobe? Explain.
7. If a bacterial strain is an obligate (strict) aerobe but catalase negative, what enzyme does the bacterium may use to detoxify H2O2?