Assessment Description:
A number of tests are used to identify a bacterial pathogen taken from human patients. Research and describe a biochemical test that is used to help determine of the genus and species of a bacteria. What bacterial types are usually identified with the use of the test you chose?
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SOLUTION to Bio-205L Microbiology Lab - Topic 5 DQ 1.
SAMPLE 1
Hello class,
During my Bachelor of Science in Nursing (BSN) program, I have learned that the catalase test along with other biochemical tests provides us with an easy and simple method to identify bacterial pathogens in clinical microbiology. This straightforward and yet efficient test helps to identify the existence of the enzyme catalase, which numerous bacteria release as a protective stance in response to oxidative stress (Gharaghani et al., 2022). The principle behind the test is that when catalase-positive bacteria are tested with hydrogen peroxide (H2O2), the enzyme quickly decomposes them into water and oxygen, thus forming bubbles.
In practice, the catalase test is carried out by adding a few drops of bacterial culture with a drop of hydrogen peroxide on a slide or a test tube. Clear bubbling is formed right after mixing of reagents in case of positive results while in case of negative results, there is no reaction at all. Giuliano et al. (2019) note that this test is valuable especially when differentiating between major groups of bacteria such as Staphylococcus and Streptococcus species, which can appear similar under microscopic examination.
By the end of the test, the bacteria that gave positive results for catalase would include pathogens such as Staphylococcus aureus, most bacteria in the Enterobacteriaceae family, Listeria monocytogenes, Bacillus species, and Pseudomonas aeruginosa. Conversely, the catalase-negative bacteria would be Streptococcus species (S.pyogenes and S. pneumoniae) and Enterococcus species (Giuliano et al., 2019). While the catalase test alone is not sufficient for definitive bacterial identification, it serves as a crucial initial step in the diagnostic process. It is often applied in combination with other tests, such as the coagulase test to help in the identification of Staphylococcus species or as a part of a multiplicity of biochemical reactions. I am confident that this set of tests enhances detection of bacterial pathogens and the clinicians' choice of how to manage their cases.
References
Gharaghani, M., Jafarian, H., Hatami, M., Shabanzadeh, M., & Mahmoudabadi, A. Z. (2022). Evaluation of catalase activity of clinical and environmental isolates of Aspergillus species. Iranian Journal of Microbiology, 14(1), 133. https://doi.org/10.18502/ijm.v14i1.8815
Giuliano, C., Patel, C. R., & Kale-Pradhan, P. B. (2019). A guide to bacterial culture identification and results interpretation. Pharmacy and Therapeutics, 44(4), 192.