Nokea
There is/are __________ level(s) of biosafety depending on the organisms handled.
- A. 1
- B. 2
- C. 3
- D. 4
Correct Answer: D
Rationale: The correct answer is D (4) because biosafety levels range from 1 to 4, each corresponding to the level of containment required when handling different types of organisms. BSL-1 is for low-risk agents, while BSL-4 is for dangerous pathogens. Choice A (1) is incorrect as there are multiple levels, not just one. Choice B (2) and C (3) are incorrect as they do not account for all the levels of biosafety required for handling various organisms. Therefore, D is the correct answer as it encompasses the full range of biosafety levels.
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Researchers of a bacteriological laboratory examine tinned meat for botulinic toxin. For this purpose a group of mice was injected with an extract of the material under examination and antitoxic antibotulinic serum of A, B, E types. A control group of mice was injected with the same extract but without antibotulinic serum. What serological reaction was applied?
- A. Neutralization
- B. Precipitation
- C. Complement binding
- D. Double immune diffusion
Correct Answer: A
Rationale: The correct answer is A: Neutralization. In this experiment, the researchers used antitoxic antibotulinic serum of different types to neutralize the botulinic toxin in tinned meat extract injected into mice. Neutralization is the process of rendering a toxin harmless by combining it with specific antibodies. The purpose of injecting the antitoxic serum was to neutralize the toxin and prevent it from causing harm to the mice. This serological reaction of neutralization directly aligns with the objective of the experiment.
Summary of other choices:
B: Precipitation - Precipitation involves the formation of a visible insoluble complex when an antigen reacts with its corresponding antibody. This process was not described in the scenario.
C: Complement binding - Complement binding involves the activation of the complement system by antigen-antibody complexes. This was not the main focus of the experiment described.
D: Double immune diffusion - This technique is used to detect the presence of specific antigens or antibodies
A 6-year-old child with suspected active tuberculosis process has undergone diagnostic Mantoux test. What immunobiological preparation was injected?
- A. Tuberculin
- B. BCG vaccine
- C. DTP vaccine
- D. Tularinum
Correct Answer: A
Rationale: The correct answer is A: Tuberculin. The Mantoux test involves injecting tuberculin, a protein derivative of Mycobacterium tuberculosis, under the skin to check for a delayed hypersensitivity reaction in individuals exposed to TB. B: BCG vaccine is a live attenuated vaccine used for TB prevention, not for diagnostic testing. C: DTP vaccine is for diphtheria, tetanus, and pertussis, not TB. D: Tularinum is not a standard immunobiological preparation used for TB testing. Therefore, A is the correct choice for the Mantoux test.
The specific antidote to botulinum toxin is:
- A. sodium bicarbonate
- B. antitoxin
- C. pralidoxime
- D. naloxone
Correct Answer: B
Rationale: The correct answer is B: antitoxin. Antitoxin is the specific antidote to botulinum toxin as it helps neutralize the toxin in the body. Sodium bicarbonate (A) is used to treat acidosis, pralidoxime (C) is used for organophosphate poisoning, and naloxone (D) is used for opioid overdose. Antitoxin directly targets and counteracts the botulinum toxin, making it the appropriate antidote in cases of botulism.
Which of the following media is often used to grow Mycobacterium tuberculosis?
- A. Middlebrook’s medium
- B. Heart infusion broth
- C. MacConkey agar
- D. Middlebrook’s medium
Correct Answer: D
Rationale: The correct answer is D: Middlebrook's medium. This medium is specifically designed for the growth of Mycobacterium tuberculosis due to its low concentration of malachite green, which inhibits the growth of other bacteria but not Mycobacterium species. Middlebrook's medium also contains various nutrients that support the growth of Mycobacterium tuberculosis.
A: Middlebrook's medium is the correct answer, not incorrect.
B: Heart infusion broth is a general-purpose medium, not specific for Mycobacterium tuberculosis.
C: MacConkey agar is selective for gram-negative bacteria and would not support the growth of Mycobacterium tuberculosis.
In summary, Middlebrook's medium is the ideal choice for cultivating Mycobacterium tuberculosis due to its specific formulation that promotes the growth of this pathogen while inhibiting other bacteria.
A 42-year-old female has foamy purulent vaginal discharges. The smear stained by Romanovsky- Giemsa's method has been found to include flagellated bacteria. What is the most likely microorganism that has been found by the doctor?
- A. Trichomonas vaginalis
- B. Leishmania donovani
- C. Trypanosoma gambiense
- D. Trihomonas hominis
Correct Answer: A
Rationale: The correct answer is A: Trichomonas vaginalis. Trichomonas vaginalis is a flagellated protozoan parasite commonly found in vaginal infections. The presence of flagellated bacteria in the vaginal discharge stained with Romanovsky-Giemsa method indicates a protozoan infection, ruling out bacterial or viral causes. Choices B, C, and D are not correct as Leishmania donovani causes leishmaniasis, Trypanosoma gambiense causes African sleeping sickness, and Trihomonas hominis is a non-pathogenic flagellate found in the human intestine, not typically associated with vaginal infections.