Nokea
Sterilization is a process that:
- A. Destroys most microorganism, but spores remain viable
- B. Leads to complete destruction of all microorganisms, including resistant forms such as spores
- C. Reduces the number of microorganisms on the surface of the skin
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B because sterilization is the process of completely destroying all microorganisms, including resistant forms like spores, ensuring no viable organisms remain. This is crucial for ensuring complete elimination of potential pathogens. Choice A is incorrect because sterilization should eliminate all microorganisms, including spores. Choice C is incorrect as it describes disinfection, not sterilization. Choice D is incorrect because sterilization aims to eradicate all microorganisms, not leave any viable ones behind.
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N. Meningitidis grows on
- A. Levine agar
- B. Lowenstein-Jensen agar
- C. TCBS agar
- D. Chocolate agar
Correct Answer: D
Rationale: The correct answer is D: Chocolate agar. Neisseria meningitidis is a fastidious organism that requires enriched media for growth. Chocolate agar contains heat-treated blood that provides essential nutrients for the growth of N. meningitidis. The other choices, A: Levine agar, B: Lowenstein-Jensen agar, and C: TCBS agar, do not provide the specific nutrients required for the growth of N. meningitidis. Therefore, only choice D, Chocolate agar, supports the growth of N. meningitidis due to its enriched composition.
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.
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.
Microscopy of a smear from a patient with foul-smelling diarrhea revealed large ciliated protozoa with a kidney-shaped macronucleus. What is the diagnosis?
- A. Balantidiasis
- B. Giardiasis
- C. Amoebiasis
- D. Trichomoniasis
Correct Answer: A
Rationale: The correct diagnosis is A: Balantidiasis. The presence of large ciliated protozoa with a kidney-shaped macronucleus is characteristic of Balantidium coli, the causative agent of balantidiasis. The ciliated trophozoites of Balantidium coli are unique compared to the other choices. Giardiasis is caused by Giardia lamblia, which has flagella and not cilia. Amoebiasis is caused by Entamoeba histolytica, which lacks cilia. Trichomoniasis is caused by Trichomonas vaginalis, which also lacks cilia. Therefore, based on the specific morphology described, the correct diagnosis is Balantidiasis.
Which of the following microorganisms can be cultured only in the footpads of mice or a species of armadillo?
- A. Mycobacterium tuberculosis
- B. Mycobacterium leprae
- C. Neisseria gonorrhoeae
- D. Mycoplasma
Correct Answer: B
Rationale: The correct answer is B: Mycobacterium leprae. This microorganism can only be cultured in the footpads of mice or a species of armadillo due to its specific growth requirements. Mycobacterium tuberculosis (choice A) can be cultured in various culture media in the laboratory. Neisseria gonorrhoeae (choice C) can be cultured on selective media like Thayer-Martin agar. Mycoplasma (choice D) can be cultured in cell cultures or specialized media. Therefore, the unique growth pattern of Mycobacterium leprae makes it the correct answer.