ATI RN
Microbiology Chapter 14 Test Bank Questions
Question 1 of 5
A patient with pulmonary tuberculosis is prescribed the most effective antituberculous antibiotic. Name this drug:
Correct Answer: D
Rationale: The correct answer is D: Rifampicin. Rifampicin is a first-line antibiotic for treating pulmonary tuberculosis due to its high efficacy against Mycobacterium tuberculosis. It works by inhibiting bacterial RNA synthesis. Furasolidone (A) is not commonly used for tuberculosis, Bactrim (B) is not a first-line drug for tuberculosis, and Streptocide (C) is not as effective as Rifampicin.
Question 2 of 5
Microscopic examination of a microbial culture revealed fusiform spore-forming microorganisms that get violet-blue Gram's stain. What microorganisms were revealed?
Correct Answer: A
Rationale: The correct answer is A: Clostridia. Fusiform spore-forming microorganisms that stain violet-blue with Gram's stain are characteristic of Clostridia. Clostridia are anaerobic, rod-shaped bacteria known for their ability to form spores and cause diseases such as tetanus and botulism. Summary of other choices: B: Streptococci are spherical, not fusiform, and typically do not form spores. C: Spirochaete are spiral-shaped bacteria and do not typically form spores. D: Actinomycete are filamentous bacteria that do not typically form spores and do not stain violet-blue with Gram's stain.
Question 3 of 5
A child cut his leg with a piece of glass while playing and was brought to the clinic for the injection of tetanus toxoid. In order to prevent the development of anaphylactic shock the serum was administered by Bezredka method. What mechanism underlies this method of desensitization of the body?
Correct Answer: A
Rationale: The correct answer is A: Binding of IgE fixed to the mast cells. The Bezredka method involves injecting small, gradually increasing doses of the antigen (tetanus toxoid) to desensitize the body and prevent anaphylactic shock. This process works by binding the IgE antibodies fixed to mast cells, thereby reducing the release of allergic mediators like histamine. This prevents the cascade of events that lead to anaphylactic shock. Choice B (Blocking the mediator synthesis in the mast cells) is incorrect because the Bezredka method does not block mediator synthesis but rather prevents the release of mediators by binding IgE. Choice C (Stimulation of immune tolerance to the antigen) is incorrect as the Bezredka method does not primarily focus on inducing immune tolerance but rather on preventing anaphylactic reactions. Choice D (Stimulation of the synthesis of antigen-specific IgG) is incorrect because the Bezredka method targets IgE antibodies on mast cells
Question 4 of 5
A bacteriological laboratory tests canned meat for botulinum toxin. Extract of the tested material and ABE botulinum antitoxin serum was introduced into the test group of mice; a control group of mice received the extract without antibotulinic serum. What serological reaction was used?
Correct Answer: A
Rationale: The correct answer is A: Neutralization. In this experiment, the ABE botulinum antitoxin serum is introduced along with the extract to neutralize the botulinum toxin. This is a specific type of serological reaction where the antitoxin serum binds to and neutralizes the toxin, preventing it from causing harm. Summary: - B: Precipitation involves the formation of visible insoluble complexes, which is not the case in this experiment. - C: Complement binding involves the activation of complement proteins, which is not the main mechanism at play here. - D: Double immunodiffusion is a technique to detect the presence of specific antigens or antibodies, but it is not directly related to the neutralization of toxins as seen in this experiment.
Question 5 of 5
In the micropreparation made from patient's regional lymph node punctate and stained according to Romanovsky-Giemsa method, the doctor found out thin microorganisms with 12-14 equal ringlets and pale- pink sharp pointes 10-13 mkm in length. The pathogen of what disease is it about?
Correct Answer: D
Rationale: The thin microorganisms described with 12-14 equal ringlets and pale-pink sharp points are characteristic of Borrelia spirochetes, the causative agent of relapsing fever. The ringlet appearance corresponds to the characteristic coiled structure of Borrelia spirochetes. The length of 10-13 mkm falls within the typical size range of Borrelia spirochetes. This pathogen is commonly identified in Romanovsky-Giemsa stained samples from patients with relapsing fever. Summary of other choices: A: Leishmaniasis - Leishmania parasites are larger and do not have the described ringlets or pale-pink sharp points. B: Leptospirosis - Leptospira bacteria are not described as having ringlets or pale-pink sharp points. C: Surra - Surra is caused by Trypanosoma evansi, and the description does not match the characteristics of this parasite.