ATI RN
microbiology chapter 14 test bank Questions
Question 1 of 5
Which enzyme is one of the most important and constant criteria for pathogenicity of staphylococcus aureus?
Correct Answer: B
Rationale: The correct answer is B: plasma coagulase. This enzyme is essential for the pathogenicity of Staphylococcus aureus as it can convert fibrinogen to fibrin, forming a protective barrier around the bacteria. This helps the bacteria evade the host's immune system. Beta lactamase (
A) is not directly related to pathogenicity but rather resistance to beta-lactam antibiotics. Catalase (
C) is produced by many bacteria, including Staphylococcus aureus, but it is not a specific indicator of pathogenicity.
Choice D is incorrect as plasma coagulase is indeed an important criterion for the pathogenicity of Staphylococcus aureus.
Question 2 of 5
After continuous treatment with antibiotics a patient got symptoms of stomatitis. Examination of specimens of oral mucous membrane revealed some oval polymorphous Gram-positive microorganisms arranged in clusters. What microorganism may be the cause of such manifestations?
Correct Answer: C
Rationale: The correct answer is C: S.aureus. Stomatitis is commonly caused by S.aureus due to its ability to form clusters of oval polymorphous Gram-positive microorganisms. S.aureus is known to colonize the oral mucous membrane and can cause infections, especially after prolonged antibiotic use.
Explanation for other choices:
A: С.albicans - Candida albicans is a fungus commonly associated with oral thrush, not typically causing stomatitis.
B: C.perfringens - Clostridium perfringens is a bacterium associated with food poisoning and gas gangrene, not commonly causing stomatitis.
D: S.pyogenes - Streptococcus pyogenes is known to cause strep throat and skin infections, but not typically associated with stomatitis.
Question 3 of 5
Agents associated with human disease but generally not a serious health risk are classified in which of the following risk groups?
Correct Answer: B
Rationale: The correct answer is B: RG2. RG2 is appropriate for agents associated with human disease that pose a moderate health risk. These agents may cause disease of varying severity, but generally do not result in serious health consequences. Other choices are incorrect because: A: RG1 is for agents not associated with disease in healthy adults, C: RG3 is for agents associated with serious or lethal human disease, and D: RG4 is for agents that pose a high risk of life-threatening disease and for which there are no treatments.
Question 4 of 5
Which bacterium is known for producing a green pigment called pyocyanin?
Correct Answer: B
Rationale: The correct answer is B: Pseudomonas aeruginosa. P. aeruginosa is known for producing pyocyanin, a green pigment. This bacterium is commonly associated with infections in immunocompromised individuals. Staphylococcus aureus (choice
A) produces golden-yellow pigments, not green. Escherichia coli (choice
C) and Clostridium difficile (choice
D) do not produce pyocyanin.
Therefore, the correct choice is B based on the characteristic pigment produced by Pseudomonas aeruginosa.
Question 5 of 5
Which statement related to the mumps vaccine is true:
Correct Answer: D
Rationale: The correct answer is D: it is a live attenuated vaccine. This is true because the mumps vaccine is indeed a live attenuated vaccine, meaning it contains a weakened form of the virus to stimulate an immune response without causing the disease. This type of vaccine provides long-lasting immunity.
A, B, and C are incorrect:
A: the vaccine is recommended, not obligatory - this is incorrect because the mumps vaccine is typically recommended for all individuals to prevent the spread of the disease.
B: the vaccine is not given in combination with other vaccines - this is incorrect as the mumps vaccine is often given in combination with measles and rubella vaccines as the MMR vaccine.
C: the vaccine is administered orally - this is incorrect because the mumps vaccine is usually administered via injection, not orally.