Detection of galactomannan and free mannan is used for diagnosing:
- A. Aspergillosis and candidiasis
- B. HIV infection
- C. Syphilis
- D. Leptospirosis
Correct Answer: A
Rationale: The correct answer is A: Aspergillosis and candidiasis. Galactomannan is a polysaccharide found in Aspergillus cell walls and is detected in patients with invasive aspergillosis. Free mannan is a polysaccharide found in Candida cell walls and is detected in patients with candidiasis. Therefore, detection of galactomannan and free mannan is specific for diagnosing Aspergillosis and candidiasis. Choices B, C, and D are incorrect as HIV infection, syphilis, and leptospirosis do not involve the detection of galactomannan or free mannan for diagnosis.
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Granulomas containing lymphocytes and macrophages were detected during analysis of skin biopsy material. Among macrophages there are large cells with fat inclusions, which contain microorganisms in spheric packages (Virchow's cells). The following disease is based on the described type of hypersensitivity:
- A. Leprosy
- B. Syphilis
- C. Tuberculosis
- D. Rhinoscleroma
Correct Answer: C
Rationale: The correct answer is C: Tuberculosis. Granulomas with lymphocytes and macrophages containing Virchow's cells (large cells with fat inclusions containing microorganisms) are classic findings in tuberculosis. Leprosy (A) typically presents with granulomas but with different histopathological features. Syphilis (B) does not usually form granulomas in the skin. Rhinoscleroma (D) is a chronic bacterial infection characterized by nodular lesions but does not typically involve Virchow's cells as seen in tuberculosis.
Which of the following bacteria produces a toxin that inhibits protein synthesis?
- A. Shigella dysenteriae
- B. Escherichia coli
- C. Clostridium tetani
- D. Staphylococcus aureus
Correct Answer: A
Rationale: Rationale: Shigella dysenteriae produces Shiga toxin, which inhibits protein synthesis by inactivating the 60S ribosomal subunit. This disrupts the translation process, leading to cell death. Escherichia coli (choice B) does not produce a toxin that inhibits protein synthesis. Clostridium tetani (choice C) produces tetanospasmin, which affects the nervous system. Staphylococcus aureus (choice D) produces toxins that cause food poisoning but do not inhibit protein synthesis.
A patient with probable liver abscess was delivered to a surgical department. The patient for a long time had been on an assignment in an African country and had recurrent cases of gastrointestinal disturbance. What protozoan disease can it be?
- A. Toxoplasmosis
- B. Leishmaniasis
- C. Malaria
- D. Amebiasis
Correct Answer: D
Rationale: The correct answer is D: Amebiasis. The patient's symptoms of gastrointestinal disturbance and liver abscess are indicative of an infection with Entamoeba histolytica, the protozoan parasite responsible for amebiasis. The patient's travel history to an African country also increases the likelihood of contracting this disease, as it is more prevalent in tropical regions. Toxoplasmosis (A) is primarily associated with exposure to cat feces, Leishmaniasis (B) is transmitted through sandfly bites, and Malaria (C) is caused by Plasmodium parasites transmitted through mosquito bites. Therefore, these options are incorrect given the patient's presentation and travel history.
What is a common characteristic of spore-forming bacteria?
- A. Resistance to heat and dehydration
- B. Ability to produce toxins
- C. Presence of flagella
- D. Ability to photosynthesize
Correct Answer: A
Rationale: The correct answer is A: Resistance to heat and dehydration. Spore-forming bacteria form spores as a survival mechanism in harsh conditions. These spores are highly resistant to heat and dehydration, allowing the bacteria to withstand extreme environments. This characteristic is essential for their long-term survival and ability to persist in unfavorable conditions. Choices B, C, and D are incorrect because not all spore-forming bacteria produce toxins, have flagella, or are capable of photosynthesis. These characteristics are not exclusive to spore-forming bacteria and do not define them as a group.
Saprophytes are microorganisms which:
- A. Can induce typical infection
- B. Cannot induce infectious disease
- C. Can induce chronic infection
- D. Can induce mixed infection
Correct Answer: B
Rationale: The correct answer is B: Cannot induce infectious disease. Saprophytes are microorganisms that obtain nutrients from decaying organic matter and do not cause infectious diseases in humans. They play a vital role in the ecosystem by decomposing dead organisms. Choice A is incorrect because saprophytes do not cause typical infections. Choice C is incorrect because saprophytes do not cause chronic infections. Choice D is incorrect because saprophytes do not cause mixed infections involving multiple pathogens. Therefore, the correct answer is B as saprophytes do not induce infectious diseases.