Nokea
A child is ill with diphtheria. A smear of the affected mucous membrane revealed blue rods with thickenings at the poles. What staining method was used?
- A. Neisser
- B. Gram
- C. Ziehl-Neelsen
- D. Loeffler
Correct Answer: A
Rationale: The correct answer is A: Neisser staining method. Neisser staining method is used to stain diphtheria bacilli, which appear as blue rods with thickenings at the poles. The rationale is that Neisser staining specifically targets and highlights the characteristics of the diphtheria bacilli.
Incorrect choices:
B: Gram staining is not specific for diphtheria bacilli and does not show the characteristic blue rods with thickenings at the poles.
C: Ziehl-Neelsen staining is used for acid-fast bacteria like Mycobacterium tuberculosis, not for diphtheria bacilli.
D: Loeffler staining is used for diphtheria bacilli but does not produce blue rods with thickenings at the poles as seen in this case.
You may also like to solve these questions
There are __________ known forms of gastroenteritis caused by Escherichia coli.
- A. two
- B. three
- C. four
- D. five
Correct Answer: D
Rationale: The correct answer is D: five. Escherichia coli can cause enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), enterohemorrhagic E. coli (EHEC), enteroaggregative E. coli (EAEC), and diffusely adherent E. coli (DAEC). Each form has distinct characteristics and pathogenesis. Therefore, the other choices (A, B, C) are incorrect because they do not accurately represent the number of known forms of gastroenteritis caused by Escherichia coli.
Which of the following bacteria produces a toxin that causes botulism?
- A. Clostridium botulinum
- B. Clostridium tetani
- C. Staphylococcus aureus
- D. Escherichia coli
Correct Answer: A
Rationale: The correct answer is A: Clostridium botulinum. Clostridium botulinum produces the botulinum toxin, which causes botulism. This bacteria thrives in anaerobic environments and can contaminate improperly canned foods. Clostridium tetani causes tetanus, not botulism. Staphylococcus aureus produces enterotoxins causing food poisoning, not botulism. Escherichia coli can cause food poisoning through various toxins, but not botulism. Therefore, the correct choice is Clostridium botulinum as it specifically produces the botulinum toxin responsible for botulism.
Young man is hospitalized in pulmonology with complaints of dry cough, fatigue and suffocations. The anamnesis and the lab tests lead to pneumocystis pneumonia. The CD4+ cells are less than 200/mm3. What test you will order:
- A. For ureaplasma urealyticum
- B. For HIV
- C. For Treponema pallidum
- D. For Neisseria gonorrhoea
Correct Answer: B
Rationale: The correct answer is B: For HIV. Pneumocystis pneumonia in a young man with CD4+ cells less than 200/mm3 is highly suggestive of HIV infection. HIV weakens the immune system, leading to opportunistic infections like pneumocystis pneumonia. Testing for HIV is crucial for diagnosis and appropriate management.
Explanation for other choices:
A: Testing for ureaplasma urealyticum is not indicated in this case as the symptoms and CD4+ cell count point towards an HIV-related infection.
C: Testing for Treponema pallidum (syphilis) is not relevant in the context of a young man with pneumocystis pneumonia and low CD4+ cell count.
D: Testing for Neisseria gonorrhoea is not appropriate in this scenario as the symptoms and CD4+ cell count suggest an underlying HIV infection rather than a bacterial sexually transmitted infection.
Laboratory diagnosis of rabies includes all of these except:
- A. Looking for Negri bodies
- B. Intracerebrally infected mice
- C. Looking for Ernst-Babes granules
- D. Immunofluorescence method
Correct Answer: C
Rationale: The correct answer is C: Looking for Ernst-Babes granules. Laboratory diagnosis of rabies typically involves looking for Negri bodies in the brain tissue, intracerebrally infecting mice for virus isolation, and using immunofluorescence method to detect viral antigens. Ernst-Babes granules are not associated with rabies virus and are not used in the diagnosis of rabies. Therefore, choice C is incorrect.
A 16-year-old adolescent was vaccinated with DTP. In eight days there was stiffness and pain in the joints, subfebrile temperature, urticarial skin eruption, enlargement of inguinal, cervical lymph nodes and spleen. What kind of allergic reaction is observed?
- A. Immunocomplex
- B. Hypersensitivity of immediate type
- C. Cytoxic
- D. Hypersensitivity of delayed type
Correct Answer: D
Rationale: The correct answer is D: Hypersensitivity of delayed type. The symptoms described occur 5-10 days after exposure to the antigen, consistent with a delayed hypersensitivity reaction. This type of reaction involves T cells and is characterized by cell-mediated immune response, leading to inflammation and tissue damage. Choices A, B, and C are incorrect because they are associated with different mechanisms of allergic reactions. Immunocomplex reactions (choice A) involve antigen-antibody complexes depositing in tissues, immediate hypersensitivity reactions (choice B) involve IgE-mediated mast cell degranulation, and cytotoxic reactions (choice C) involve antibodies targeting specific cells for destruction.