What is the importance of the catalase test other than the information provided

Question

What is the importance of the catalase test other than the information provided in this lab’s introduction?

Introduction The first line of defense against bacterial infections are the skin and mucous membranes (found in the respiratory system). In humans, the skin has an average surface area of almost 2 m2 and has a variable thickness of between 0.05 mm and 0.33 mm. The dry outer layer of the skin consists of numerous rows of dead epidermis called keratin. On the keratin layer perspiration and sebum (skin oil) form what is referred to as the acid mantle (so-called because of the range of pH which is from 4 to 5.5) The respiratory system contains a set of defenses. The cilia move unwanted particles up from the lower respiratory system to upper respiratory system to exit from the throat. That mechanism is called the ciliary escalator. Microorganisms that actually reach the lungs are destroyed by alveolar macrophages Additionally, IgA antibodies are in the secretions of respiratory mucus, saliva, and tears. The system of microphages and antibodies are referred to as microbial antagonism. In spite of the body's defenses, there are bacteria that thrive in these inhospitable environments. Today in lab, you will culture and attempt to identify microbes that you collect from yourselves in lab Mannitol salt agar is a differential medium that will turn yellow when being fermented by staphylococci. One of the most abundant microbes found on human skin is Staphylococcus aureus. Today in lab, you wil collect skin swabs and culture them on mannitol salt agar The catalase test can be used to differentiate staphylococci (produces catalase and bubbles in the prescen of hydrogen peroxide) and streptococci (which do not produce catalase). You will perform the catalase test in both procedures. Aseptically place a loopful of bacteria on a clean slide then apply one drop of hydrogen peroxide onto the bacteria. If bubbles are produced, then the organism is positive for the presence of catalase

Explanation / Answer

Catalase is an enzyme, produced by microorganisms that live in oxygenated environments to neutralize toxic forms of oxygen metabolites; H2O2. It catalyses the release of oxygen from hydrogen peroxide (H2O2). Catalase-positive bacteria include strict aerobes as well as facultative anaerobes. They all have the ability to respire using oxygen as a terminal electron acceptor. Catalase-negative bacteria may be anaerobes, or facultative anaerobes which do not have oxygen as terminal electron aaceptor. Apart from the use given above, the catalase test can also be used for : Aerobic and Obligate anaerobic bacteria can be differentiated by using catalase test, as aerobic organisms are catalase positive and anaerobic are catalase negative Semiquantitative catalase test is used for the identification of Mycobacterium tuberculosis. It is used to differentiate aerotolerant strains of Clostridium, which are catalase negative, from Bacillus species, which are positive. Catalase test can be used as an aid for the identification of Enterobacteriaceae. Members of Enterobacteriaceae family are usually catalase positive.

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