Micro Practice Practical For Perryman Lab

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Coagulase is an enzyme produced by Staphylococcus aureus that is responsible for the formation of fibrin clots. This ability is unique to Staphylococcus aureus and is not found in other staphylococcal species. Coagulase plays a crucial role in the pathogenesis of Staphylococcus aureus infections by helping the bacteria evade the host immune response and form protective barriers.

The Urease Test is a biochemical test used to determine the ability of an organism to produce the enzyme urease. Urease hydrolyzes urea to produce ammonia and carbon dioxide. In this test, a pH indicator called Phenol Red is used. Phenol Red is red at a neutral pH (around 7), but turns yellow at an acidic pH (below 6.8) and pink at a basic pH (above 8.2). Since the Urease Test is designed to detect the production of ammonia, which is basic, a positive result (indicating the presence of urease) is indicated by a color change from red to pink, confirming that the pH has become more basic. Therefore, the statement that Urease Test has a pH indicator of Phenol Red is true.

The interpretation for the given test result is that the organism tested is positive for urease. Urease is an enzyme produced by certain bacteria that breaks down urea into ammonia and carbon dioxide. A positive result in the urease test indicates that the organism is capable of producing urease and can hydrolyze urea. This is supported by the media turning hot pink, which is a characteristic color change associated with a positive urease reaction.

The catalase test causes bubbling in Staphs. This reaction occurs because catalase is an enzyme that breaks down hydrogen peroxide into water and oxygen. When hydrogen peroxide is added to a sample containing Staphylococci, the catalase enzyme present in the bacteria catalyzes the breakdown of hydrogen peroxide, resulting in the release of oxygen gas. This release of oxygen gas causes bubbling to occur, indicating a positive catalase test.

The interpretation for the given result is that the colonies grow well but there is no change in the medium. This indicates that the test result is gamma.

The given results indicate that both the slant and the butt of the Triple Sugar Iron (TSI) test turned yellow, which corresponds to an acidic environment. Therefore, the correct answer is A/A, indicating an acid production in both glucose and lactose/sucrose fermentation.

The result "K/A" indicates that the Pink Slant is alkaline (K) and the Yellow Butt is acidic (A). This result suggests that glucose fermentation has occurred, producing acid in the butt of the tube, while lactose and/or sucrose fermentation has also occurred, producing alkali in the slant of the tube.

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Catalase is indeed a fast test that can be used to differentiate between Staphylococcus and Streptococcus organisms. This test involves adding hydrogen peroxide to a bacterial culture, and if the bacteria produce the enzyme catalase, they will break down the hydrogen peroxide into water and oxygen, resulting in the formation of bubbles. Staphylococcus species produce catalase, while Streptococcus species do not. Therefore, the statement that catalase is a fast test to determine whether an organism is a Staph or Strep is true.

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Catalase is the correct answer for this question. Catalase is an enzyme that is found in cells and helps to break down hydrogen peroxide into water and oxygen gas. It plays a crucial role in protecting cells from the harmful effects of hydrogen peroxide, which is a byproduct of various metabolic processes. By catalyzing the decomposition of hydrogen peroxide, catalase ensures that it is converted into harmless substances, preventing any damage to the cell.

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MSA (Mannitol Salt Agar) is a selective and differential medium used to identify and isolate Staphylococcus species. It contains high salt concentration, which inhibits the growth of most bacteria except for Staphylococcus, which can tolerate high salt levels. The medium also contains mannitol sugar, which is fermented by certain Staphylococcus species, causing a change in the pH of the agar and resulting in a yellow color change. Therefore, the presence of yellow colonies on MSA indicates the presence of Staphylococcus.

The interpretation for the given test result is that the colonies exhibit beta hemolysis. This is indicated by the presence of a clear zone around the colonies on the plate, which becomes see-through when held up to light.

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If the MSA agar turns yellow, it indicates a low pH level. This change in color suggests that the bacteria present on the agar have fermented the mannitol sugar, producing acid as a byproduct. Therefore, the result is interpreted as positive for mannitol fermentation.

Hemolysis refers to the breakdown or destruction of red blood cells. This process can occur due to various factors such as infections, toxins, or certain medical conditions. When red blood cells undergo hemolysis, their membranes rupture, leading to the release of their contents into the surrounding fluid. This can result in the release of hemoglobin, which gives the characteristic red color to blood, and other cellular components. Hemolysis can have detrimental effects on the body, including anemia and the release of substances that can cause inflammation and damage to tissues.

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EMB has lactose which detects lactose fermentation in EMB media.

The correct answer is blood because the hemolysis test is performed on blood agar. This test is used to determine the ability of bacteria to break down red blood cells. Different types of hemolysis patterns can be observed on the blood agar, including alpha, beta, and gamma hemolysis, which can help in identifying different bacterial species.

The interpretation for the given result is that the colonies exhibit a brownish green zone when held up to light, which indicates an Alpha hemolysis.

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Mannitol is the component that makes MSA (Mannitol Salt Agar) differential. MSA is a selective and differential medium used for the isolation and differentiation of Staphylococcus aureus from other staphylococci. The high concentration of salt (7.5% NaCl) in MSA inhibits the growth of most bacteria except for staphylococci. Staphylococcus aureus, which can ferment mannitol, produces acid that lowers the pH of the medium, causing a color change in the pH indicator phenol red from red to yellow. Other staphylococci that cannot ferment mannitol do not produce acid and the medium remains red. Therefore, the ability to ferment mannitol differentiates S. aureus from other staphylococci.

Phenol Red in the Urease Test is turned hot pink by ammonia. This is because ammonia is alkaline and causes a change in the pH of the solution, causing the phenol red indicator to shift from its original color to hot pink.

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If DNase is present than the DNA will be broken down leaving the agar colorless.

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Catalase has No reaction for Streps

The interpretation of the result "Media turns Yellow" in the Urease Test is that the test is negative for Urease. This means that the organism being tested does not produce the enzyme urease, which is responsible for breaking down urea into ammonia and carbon dioxide. If the test were positive for Urease, the media would turn pink or magenta due to the presence of ammonia. Therefore, the correct answer is Negative for Urease.

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Staphylococcus is halophilic because it is able to tolerate high salt concentrations. This bacterium can survive and thrive in environments with high salt content, such as salty foods or the human skin. Streptococcus, on the other hand, is not halophilic and does not have the ability to tolerate high salt concentrations.

The correct answer is Alpha Beta Gamma. This suggests that streps have three distinct classes: Alpha, Beta, and Gamma.

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fig. 19.3

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Selective and differential media (SD media) is a type of culture medium that is designed to selectively promote the growth of certain microorganisms while inhibiting the growth of others. It contains specific nutrients or chemicals that favor the growth of particular organisms, allowing them to grow while suppressing the growth of other organisms. Additionally, SD media also contains indicators that can differentiate between different types of microorganisms based on their metabolic activities or biochemical characteristics. Therefore, MSA (Mannitol Salt Agar) can be classified as both selective and differential media as it selects for the growth of salt-tolerant bacteria and differentiates between bacteria based on their ability to ferment mannitol.

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Gram's Iodine is added to media after incubation to determine the presence of Amylace.

The given correct answer is A/A, H2S. This indicates that the test result shows a yellow slant and a black butt, which signifies an acid reaction. Additionally, the presence of H2S (hydrogen sulfide) is indicated.

When Urease reacts with Water, it produces 2 molecules of Ammonia (NH3) and 1 molecule of Carbon Dioxide (CO2). Therefore, the correct answer is 2NH3+CO2.

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If Amylase is present than the Starch will be broken down leaving the agar colorless.

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