ATI RN
microbiology test bank Questions
Question 1 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 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 (T
B) 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
Which of the following organisms is the causative agent of skin infections and toxic shock syndrome?
Correct Answer: B
Rationale: The correct answer is B: Staphylococcus aureus. This bacteria is known to cause skin infections and toxic shock syndrome due to its ability to produce toxins that can lead to severe symptoms. Staphylococcus aureus is commonly found on the skin and can enter the body through cuts or wounds, causing infections. Other choices are incorrect because Pseudomonas aeruginosa typically causes infections in immunocompromised individuals, Micrococcus luteus is a common skin bacterium that is not typically pathogenic, and Propionibacterium acnes is associated with acne, not skin infections or toxic shock syndrome.
Question 4 of 5
Each of the following statements concerning gram-negative rods is correct EXCEPT:
Correct Answer: A
Rationale:
Rationale:
A is incorrect because whooping cough resurgence is mainly due to decreased vaccine immunity, not changing antigenicity.
B is correct as P. aeruginosa can indeed cause infections with blue-green pus due to its pigment production.
C is correct as H. influenzae type b capsule is a virulence factor contributing to invasive disease.
D is correct as Legionella infection is acquired via inhalation of contaminated water aerosols.
Therefore, A is incorrect as the rise in whooping cough is not due to changing antigenicity but vaccine immunity decline.
Question 5 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.