Nokea
The spores of bacteria can be stained by:
- A. Methods of Romanovski-Gymsa
- B. Method of Ziehl-Nielsen
- C. Method of Moller
- D. Method of Neisser
Correct Answer: C
Rationale: The correct answer is C: Method of Moller. This method uses malachite green to stain bacterial spores due to their resistance to decolorization. The other choices, A, B, and D, are incorrect because Romanovski-Gymsa is used for staining blood smears, Ziehl-Nielsen is used for acid-fast bacteria, and Neisser is used for staining Neisseria species, not bacterial spores.
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Polyclonal antibodies can respond to multiple antigens:
- A. TRUE
- B. FALSE
- C. All of the above
- D. None of the above
Correct Answer: A
Rationale: Polyclonal antibodies are produced by different B cells, each recognizing a different epitope on an antigen. Therefore, they can respond to multiple antigens. This diversity in recognition allows polyclonal antibodies to bind to various targets, making option A true. Options B, C, and D are incorrect as they do not accurately reflect the nature of polyclonal antibodies' ability to recognize multiple antigens.
Coxsackie Viruses can cause:
- A. Hemorrhagic conjunctivitis
- B. Herpangina
- C. Mumps
- D. Poliomyelitis
Correct Answer: B
Rationale: The correct answer is B: Herpangina. Coxsackie Viruses are known to cause Herpangina, which is characterized by sore throat, fever, and painful blisters in the mouth and throat. This is because Coxsackie Viruses typically infect the throat and mouth mucosa. Hemorrhagic conjunctivitis (A) is commonly caused by Adenoviruses, not Coxsackie Viruses. Mumps (C) is caused by the Mumps virus, a completely different virus. Poliomyelitis (D) is caused by the Poliovirus, not Coxsackie Viruses. Therefore, the correct answer is B as it aligns with the known pathogenicity of Coxsackie Viruses.
While studying a microslide obtained from the punctuate of a regional lymph node and stained by Romanovsky-Giemsa method a physician revealed some light pink thin microorganisms with 12-14 regular spiral coils and pointed ends, up to 10-13 micrometer long. This might be the causative agent of the following disease:
- A. Syphilis
- B. Trypanosomiasis
- C. Leptospirosis
- D. Relapsing fever
Correct Answer: D
Rationale: The correct answer is D: Relapsing fever. The description matches Borrelia species, the causative agent of relapsing fever. The thin, spiral-shaped microorganisms with pointed ends and specific length are characteristic of Borrelia. The number of coils and size mentioned also align with Borrelia morphology. Relapsing fever is transmitted by tick bites and manifests as recurring febrile episodes.
Incorrect choices:
A: Syphilis - Syphilis is caused by Treponema pallidum, which is not spiral-shaped.
B: Trypanosomiasis - Trypanosomiasis is caused by Trypanosoma species, which are not spiral-shaped.
C: Leptospirosis - Leptospirosis is caused by Leptospira species, which are not spiral-shaped and do not match the specific description provided.
On a certain territory mass death of rodents was registered. It was suspected that their death might have been caused by plague. What serological reaction should be applied for quick identification of antigen of the causative agent of this epizooty?
- A. Precipitation
- B. Agglutination
- C. Passive hemagglutination
- D. Complement binding
Correct Answer: B
Rationale: The correct answer is B: Agglutination. During a suspected plague outbreak, agglutination testing is used to quickly identify the antigen of the causative agent. In this test, specific antibodies are added to a sample containing the suspected antigen. If the antigen is present, it will clump together (agglutinate) with the antibodies, indicating a positive result. This method is rapid and efficient for identifying the presence of the plague-causing agent.
Choice A: Precipitation involves the formation of a visible precipitate when antigen and antibody react, but it is not as quick or specific as agglutination for identifying the antigen in this scenario.
Choice C: Passive hemagglutination is a variation of agglutination that uses red blood cells as carriers for antigens or antibodies. While it can be useful in certain situations, it is not typically the first choice for rapid identification of plague antigen.
Choice D: Complement binding is a different type of
A patient with severe abdominal pain and vomiting had a blood culture that revealed Gram-negative rods producing gas. What is the most likely causative agent?
- A. Escherichia coli
- B. Salmonella enteritidis
- C. Clostridium perfringens
- D. Campylobacter jejuni
Correct Answer: B
Rationale: The correct answer is B: Salmonella enteritidis. In this case, the presence of Gram-negative rods producing gas in the blood culture indicates a likelihood of Salmonella infection, as it is a common cause of severe abdominal pain, vomiting, and gas production. Salmonella enteritidis is a known pathogen that can cause gastroenteritis and systemic infections. Escherichia coli (choice A) can also cause similar symptoms, but it is less likely to produce gas in blood culture. Clostridium perfringens (choice C) typically causes food poisoning with rapid onset and less likely to be isolated from blood cultures. Campylobacter jejuni (choice D) is associated with gastroenteritis but is less likely to cause systemic infections with gas-producing Gram-negative rods in blood culture.