The key difference between catalase and coagulase test is that the catalase test is performed to understand the biochemical process of hydrogen peroxide detoxification by aerobic bacteria through the production of the enzyme called catalase, while the coagulase test is performed to understand the biochemistry of the enzyme coagulase that is only produced by pathogenic bacterial species such as Staphylococci.
Biochemical tests are among the most important and popular methods for identifying microbes. Microbial biochemistry tests usually reduce the time and cost required to identify microbes and ensure the accuracy of the identification of specific microbes. Catalase and coagulase test are two biochemical tests used to differentiate bacteria in laboratories.
CONTENTS
1. Overview and Key Difference
2. What is Catalase Test
3. What is Coagulase Test
4. Similarities – Catalase and Coagulase Test
5. Catalase vs. Coagulase Test in Tabular Form
6. Summary – Catalase vs. Coagulase Test
What is Catalase Test?
A catalase test is usually performed to differentiate aerobic bacteria from anaerobic bacteria. This test examines how aerobic bacteria detoxify hydrogen peroxide using the enzyme catalase. To survive, organisms like bacteria must rely on defense mechanisms that help them to repair oxidative damage from H2O2. Some bacteria produce the catalyzing enzyme that helps this cellular detoxification.
Figure 01: Catalase Test
Catalase is a common enzyme found in nearly all living organisms exposed to oxygen, including bacteria, plants, and animals. It catalyzes the decomposition of hydrogen peroxide into water and oxygen. Catalase also has one of the highest turnover numbers compared to all other enzymes in organisms. In bacterial identification, the catalase test is performed by placing a drop of hydrogen peroxide on a microscope slide. Then an applicator stick is touched to the bacterial colony, and the tip of the applicator stick is later smeared onto the hydrogen peroxide drop. If this mixture produces bubbles or froth, the organism is said to be catalase-positive. Furthermore, this test differentiates catalase-positive Staphylococcaceae and Micrococcaceae bacterial species from catalase-negative Streptococcaceae bacterial species. In addition, it is also helpful in distinguishing between species in the same genus, like Aerococcus urinae, which is catalase positive, from Aerococcus viridians, which is catalase negative.
What is Coagulase Test?
A coagulase test is done to understand the biochemistry of the enzyme coagulase that is only produced by pathogenic bacterial species such as Staphylococci. Coagulases are exoenzymes that normally clot the blood plasma, similar to normal clotting, by a mechanism. The coagulase test identifies whether an organism like bacteria can produce this exoenzyme. Coagulase clots the plasma component of blood. In humans, Staphylococcus aureus is the primary bacterial pathogen known to cause significant blood plasma coagulation.
Figure 02: Coagulase Test
In this test, the bacterial sample is added to rabbit plasma and held at 37° C for a specified period. The coagulation or clot formation that occurs within hours is interpreted as a positive result for the coagulase test. Furthermore, it also indicates the presence of a virulent Staphylococcus aureus strain. On the other hand, the absence of coagulation after 24 hours indicates the presence of an avirulent strain.
What are the Similarities Between Catalase and Coagulase Tests?
- Catalase and coagulase test are two biochemical tests used to differentiate bacteria in laboratories.
- Both are conventional tests to identify microbes like bacteria.
- They use the presence or absence of a particular enzyme (exoenzyme) production to differentiate bacteria in both tests.
- Both can be used to differentiate pathogenic species of bacteria from non-pathogenic bacteria.
- Both are readily available in common microbiological laboratories.
- They are usually cheaper tests.
What is the Difference Between Catalase and Coagulase Test?
The catalase test is performed to understand the biochemical process of hydrogen peroxide detoxification by aerobic bacteria through the production of catalase, while the coagulase test is performed to understand the biochemistry of coagulase that is only produced by pathogenic bacterial species such as Staphylococci. Thus, this is the key difference between catalase and coagulase test. Furthermore, catalase tests are more common biochemical tests, while coagulase tests are less common biochemical tests.
The infographic below presents the differences between catalase and coagulase test in tabular form for side-by-side comparison.
Summary – Catalase vs. Coagulase Test
Conventional biochemical tests used in the microbiology laboratory for identifying bacteria of interest are beta-glucuronidase (MUG) test, bile solubility test, CAMP test, catalase test, citrate utilization test, coagulase test, DNase test, indole test, etc. A catalase test uses the presence or absence of catalase exoenzyme production to differentiate bacteria. At the same time, a coagulase test uses the presence or absence of coagulase exoenzyme production to distinguish the bacteria. So, this is the key difference between catalase and coagulase test.
Reference:
1. “Catalase Test.” ASM.Org.
2. Aryal, Sagar, et al. “Coagulase Test- Principle, Procedure, Types, Interpretation and Examples.” Microbiology Info.Com.
Image Courtesy:
1. “Catalase reaction” By No machine-readable author provided. Nase assumed – Own work assumed (based on copyright claims). (CC BY-SA 3.0) via Commons Wikimedia
2. “Tube coagulase test of Staphylococcus aureus -Positive and negative Demonstration” By Ajay Kumar Chaurasiya – Own work (CC BY-SA 4.0) via Commons Wikimedia
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