ATI RN
microbiology chapter 10 test bank Questions
Question 1 of 9
Which bacteria are resistant to antibiotics and commonly found in hospitals?
Correct Answer: A
Rationale: The correct answer is A, Staphylococcus aureus (MRSA), because it is known to be resistant to many antibiotics commonly used in hospitals. MRSA poses a significant threat in healthcare settings due to its resistance, making it difficult to treat. Choice B, Escherichia coli, is not typically resistant to antibiotics. Choice C, Salmonella enterica, and Choice D, Vibrio cholerae, are not commonly associated with antibiotic resistance in hospitals. Therefore, A is the correct answer based on its well-documented antibiotic resistance in healthcare settings.
Question 2 of 9
What means significant bacteriuria:
Correct Answer: A
Rationale: The correct answer is A because significant bacteriuria is defined as having more than 10^5 cells in 1 ml of midstream morning urine. This concentration indicates a true infection rather than contamination. Choice B is incorrect because the amount of urine does not determine significant bacteriuria. Choice C is incorrect because even a single bacterium in urine does not necessarily indicate an infection. Choice D is incorrect because not all statements are correct; only choice A accurately defines significant bacteriuria based on the bacterial concentration in urine samples.
Question 3 of 9
Ziehl-Neelsen staining is for detection of:
Correct Answer: A
Rationale: Step 1: Ziehl-Neelsen staining is a type of acid-fast staining used to detect acid-resistant bacteria like Mycobacterium species. Step 2: Acid-resistant bacteria have a high lipid content in their cell walls, making them resist decolorization with acid-alcohol. Step 3: Mycobacterium species, such as M. tuberculosis and M. leprae, are examples of acid-resistant bacteria. Step 4: Spores are not typically stained using Ziehl-Neelsen staining, making choice B incorrect. Step 5: Metachromatic bodies are stained using specific techniques like Albert's stain, not Ziehl-Neelsen staining, making choice C incorrect. Summary: Ziehl-Neelsen staining is specifically used for acid-resistant bacteria detection, making choice A the correct answer. Choices B and C are incorrect as they do not align with the purpose of Ziehl-Neelsen staining. Choice D is incorrect as Ziehl
Question 4 of 9
“Animalcules†were first described by
Correct Answer: B
Rationale: The correct answer is B, Antony van Leeuwenhoek. He was the first to observe and describe "animalcules" (microorganisms) through his early microscopes. Robert Hooke (A) is known for his work with cells but did not discover animalcules. Hans Janssen (C) and John Needham (D) did not make significant contributions to the discovery of microorganisms. Leeuwenhoek's pioneering observations were crucial in the development of microbiology.
Question 5 of 9
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 6 of 9
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.
Question 7 of 9
Not many bacterial species in nature form spores. Which of the following genera have this ability?
Correct Answer: C
Rationale: The correct answer is C: Bacillus, Clostridium. Both Bacillus and Clostridium are known to form spores. Bacillus species produce endospores, which are resistant structures for survival in harsh conditions, while Clostridium species also form spores for protection and dispersal. The other choices are incorrect because Borrelia and Treponema are spirochetes and do not form spores, Bacteroides and Fusobacterium are anaerobic bacteria that do not produce spores, and Bordetella and Brucella are non-spore forming bacteria as well.
Question 8 of 9
Reassortment of gene segments can occur in one of the following families:
Correct Answer: B
Rationale: The correct answer is B: Family Reoviridae. Reassortment of gene segments occurs in segmented viruses like Reoviruses. In Reoviridae, each segment encodes a specific protein, allowing for reassortment to generate new strains. Togaviridae (A) is a non-segmented virus, not capable of reassortment. Picornaviridae (C) and Paramyxoviruses (D) are also non-segmented viruses, limiting their ability for reassortment. Therefore, the correct choice is B due to the segmented nature of Reoviruses allowing for genetic reassortment.
Question 9 of 9
Tuberculine was injected intracutaneously to the child for tuberculin test. Marked hyperemia, tissue infiltration developed on the place of injection in 24 hours. What mechanism caused these modifications?
Correct Answer: C
Rationale: The correct answer is C: Granuloma formation. In response to tuberculosis antigen (tuberculin), the immune system forms a granuloma at the injection site as a defense mechanism. Granulomas are organized collections of immune cells that wall off the antigen and prevent its spread. This process involves macrophages, T cells, and fibroblasts. Choice A (Cells cytotoxity) is incorrect because tuberculin test does not involve direct cell cytotoxicity. Choice B (Reagin type cytotoxity) is incorrect as reagin type hypersensitivity is associated with allergic reactions, not granuloma formation. Choice D (Immunocomplex cytotoxity) is also incorrect as immunocomplex cytotoxicity refers to tissue damage caused by immune complexes, not granuloma formation.