ATI RN
microbiology chapter 10 test bank Questions
Question 1 of 5
A Gram-positive, spore-forming bacterium was isolated from a wound infection. The bacteria were anaerobic and produced gas. What is the likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Clostridium perfringens. This bacterium is Gram-positive, spore-forming, anaerobic, and produces gas. Clostridium perfringens is commonly associated with wound infections due to its ability to produce gas gangrene.
Choice B: Bacillus anthracis is also a Gram-positive, spore-forming bacterium, but it does not typically produce gas in wound infections.
Choice C: Clostridium botulinum is a spore-forming, anaerobic bacterium, but it is associated with foodborne botulism rather than wound infections.
Choice D: Clostridium tetani is a spore-forming, anaerobic bacterium that causes tetanus, but it does not produce gas in wound infections.
Question 2 of 5
An infectious diseases hospital admitted a veterinarian with assumed brucellosis. What serologic test can confirm this diagnosis?
Correct Answer: A
Rationale: The correct answer is A: Wright's agglutination reaction. For brucellosis diagnosis, this test detects antibodies against Brucella species. Wright's test specifically targets agglutinins, which are produced in response to Brucella infection. The other choices are incorrect because:
B: Widal's test is used for typhoid fever caused by Salmonella typhi.
C: Ascoli's test is for pneumococcal infections.
D: Weigl's test is used for typhus fever caused by Rickettsia prowazekii.
Question 3 of 5
Degenerative changes resulting from viral propagation in infected cell cultures are referred as:
Correct Answer: B
Rationale: The correct answer is B: cytopathic effect. When viruses infect cell cultures, they induce degenerative changes known as cytopathic effects, which include cell shrinkage, rounding, detachment, and cell death. This term specifically refers to the damage caused by viral replication within the cells.
A: Cytolytic effect refers to the destruction of cells by viruses, which is a more specific type of cytopathic effect involving cell lysis.
C: Cytotoxic effect typically refers to the toxic effects of substances on cells, not specifically related to viral propagation.
D: The statement that all three answers are correct is incorrect as only option B accurately describes the degenerative changes resulting from viral propagation in infected cell cultures.
Question 4 of 5
Which of the following bacteria can form spores that are resistant to extreme conditions?
Correct Answer: B
Rationale: The correct answer is B: Bacillus subtilis. Bacillus subtilis is a Gram-positive bacterium known for forming endospores, which are resistant structures that allow the bacteria to survive harsh conditions like heat, radiation, and desiccation. This ability to form spores helps Bacillus subtilis to endure unfavorable environments. Staphylococcus aureus (
A), Pseudomonas aeruginosa (
C), and Neisseria gonorrhoeae (
D) do not form spores and lack the same level of resistance to extreme conditions as Bacillus subtilis.
Question 5 of 5
A patient with pneumonia had sputum cultured revealing Gram-negative diplococci. The bacteria were oxidase-positive and fermentative. What is the most likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Neisseria meningitidis. This bacterium fits the description of Gram-negative diplococci that are oxidase-positive and fermentative. Neisseria meningitidis commonly causes pneumonia and meningitis.
Choice B: Neisseria gonorrhoeae is also a Gram-negative diplococci but is not fermentative.
Choice C: Moraxella catarrhalis is oxidase-positive but not fermentative.
Choice D: Haemophilus influenzae is not fermentative and typically appears as pleomorphic rods, not diplococci.