ATI RN
Microbiology Test Bank Questions
Question 1 of 5
A 5-year-old kindergartener has diphtheria. To find the carriers of the disease among the kindergarten staff, samples of pharyngeal mucus were obtained from the employers. One of the employers had gram-positive bacilli in her sample. They were situated at an angle to each other and colored unevenly, when stained according to Loeffler. What method can confirm that this carrier is dangerous to other people?
Correct Answer: A
Rationale: The correct answer is A: Toxin production test. Rationale: 1. Diphtheria is caused by a toxin produced by Corynebacterium diphtheriae. 2. To confirm if the carrier is dangerous, we need to test if they are producing the toxin. 3. The toxin production test directly assesses if the bacteria are producing the harmful toxin. 4. Positive results indicate the carrier is dangerous and can transmit the disease to others. Summary of other choices: B: Mouse neutralization test - Used to detect diphtheria antitoxin levels in blood, not to confirm if the carrier is dangerous. C: Immunofluorescence test - Used to detect specific antigens or antibodies, not directly related to confirming the carrier's danger. D: Complement fixation test - Measures immune response, not specific to toxin production confirmation.
Question 2 of 5
First-year schoolchildren have received tuberculin skin test (Mantoux test) at the school nurse's office. The purpose of this test was:
Correct Answer: D
Rationale: The correct answer is D: To determine the children that need to receive BCG vaccination. The Mantoux test is used to identify individuals who have been exposed to Tuberculosis (TB) and need BCG vaccination for protection. Parotitis (choice A) is a viral infection unrelated to TB. Allergization rate toward rickettsia (choice B) and immune stress toward diphtheria (choice C) are not related to the Mantoux test or BCG vaccination. Therefore, choice D is the correct answer as it aligns with the purpose of the Mantoux test.
Question 3 of 5
A smear of streptobacillus preparation stained by Ozheshko method has been studied microscopically with oil immersion. What structural feature of the bacteria has been studied?
Correct Answer: D
Rationale: The correct answer is D: Structure of cell wall. When studying a bacterial smear stained by the Ozheshko method, the focus is on the cell wall structure. This staining method highlights the cell wall morphology, allowing for detailed examination. Flagella, spores, and capsules are not typically visualized using this staining method. Flagella require special staining techniques, spores are usually observed through specific staining methods like Schaeffer-Fulton, and capsules are not easily visualized with the Ozheshko staining method. Therefore, the structure of the cell wall is the most relevant feature to study in this context.
Question 4 of 5
Those organisms which in the process of evolution failed to develop protection from H O can exist 2 2 only in anaerobic conditions. Which of the following enzymes can break hydrogen peroxide down?
Correct Answer: A
Rationale: The correct answer is A: Peroxidase and catalase. Peroxidase and catalase are enzymes that break down hydrogen peroxide into water and oxygen. Peroxidase helps in breaking down low levels of hydrogen peroxide, while catalase is crucial for breaking down high levels of hydrogen peroxide efficiently. This process is important for organisms to prevent damage from reactive oxygen species. Choices B, C, and D are incorrect: B: Oxygenase and hydroxylase are enzymes involved in different biochemical reactions and do not break down hydrogen peroxide. C: Cytochrome oxidase and cytochrome B5 are involved in electron transport chain reactions and not in breaking down hydrogen peroxide. D: Oxygenase and catalase are not correct as oxygenase is not involved in hydrogen peroxide breakdown, only catalase is.
Question 5 of 5
A 10-year-old child cut his leg with a piece of glass and was sent to a clinic for an anti-tetanus serum injection. In order to prevent the development of anaphylactic shock, the Besredka desensitization method was applied. What mechanism underlies this method?
Correct Answer: A
Rationale: The correct choice is A: Binding to IgE fixed to mast cells. The Besredka desensitization method involves injecting small, gradually increasing doses of the allergen to induce tolerance and prevent anaphylactic shock. This process works by binding the allergen to IgE antibodies fixed to mast cells, which prevents the release of histamine and other inflammatory mediators that trigger allergic reactions. This desensitization process helps the immune system become less reactive to the allergen over time. Incorrect choices: B: Inhibited synthesis of mast cells mediators - This choice does not reflect the mechanism of the Besredka desensitization method, which involves binding to IgE on mast cells. C: Stimulation of the immunological antigen tolerance - While this may sound plausible, the Besredka method specifically targets the IgE-mast cell interaction. D: Stimulation of antigen-specific IgG synthesis - While IgG antibodies may play a role in desensitization, the