Nokea
Which statements is NOT CORRECT: Treponema pallidum can be cultivated on:
- A. Artificial food media
- B. Cell lines
- C. Intratesticular in rabbits
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: Artificial food media. Treponema pallidum is a fastidious bacterium that cannot be cultivated on artificial food media due to its complex nutritional requirements. It can be cultivated on cell lines and intratesticular in rabbits. Therefore, option A is incorrect. Option B and C are correct.
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In 8 days after a surgery the patient developed tetanus. The surgeon suspects this condition to be caused by suture material contaminated by tetanus agent. The material is delivered to a bacteriological laboratory. What nutrient medium is required for primary inoculation of the suture material?
- A. Kitt-Tarozzi medium.
- B. Endo agar.
- C. Sabouraud agar.
- D. Egg-yolk salt agar.
Correct Answer: A
Rationale: The correct answer is A: Kitt-Tarozzi medium. This medium is used for the primary inoculation of suture material suspected of causing tetanus. The rationale is that Kitt-Tarozzi medium contains the necessary nutrients to support the growth of Clostridium tetani, the bacterium responsible for tetanus. This medium is selective and helps in isolating the specific pathogen from the contaminated suture material.
Summary of other choices:
B: Endo agar is used for the isolation of Gram-negative bacteria from clinical and non-clinical samples.
C: Sabouraud agar is used for the isolation of fungi and yeast.
D: Egg-yolk salt agar is used for the detection of lipase-producing bacteria, particularly Staphylococcus aureus.
The immunity in syphilis is:
- A. Nonsterile (infectious)
- B. Antitoxic
- C. Humoral
- D. A + B + C
Correct Answer: A
Rationale: The correct answer is A because immunity in syphilis is nonsterile, meaning that individuals who have been infected may still carry the bacteria and be capable of transmitting the disease. This is due to the ability of the bacterium causing syphilis, Treponema pallidum, to evade the immune system by hiding within host cells.
Option B, antitoxic, is incorrect because syphilis is not caused by a toxin produced by the bacteria, but rather by the bacterium itself.
Option C, humoral, is also incorrect as syphilis immunity involves both humoral (antibody-mediated) and cell-mediated immune responses, not solely humoral immunity.
Option D is incorrect as it includes all three options, whereas in reality, the immunity in syphilis is primarily nonsterile.
In the South and Central America there can be found a species of trypanosomes that is the causative agent of Chagas disease. What animal is the infection carrier specific to this disease?
- A. Triatomine bug
- B. Mosquito
- C. Tsetse fly
- D. Cockroach
Correct Answer: A
Rationale: The correct answer is A: Triatomine bug. Triatomine bugs, also known as "kissing bugs," are the specific carrier of the trypanosomes that cause Chagas disease. These bugs transmit the parasite through their feces, which contain the infectious forms of the trypanosomes. When the bug bites a human or animal, it defecates near the bite wound, allowing the parasites to enter the bloodstream through the broken skin. Mosquitoes (B) transmit diseases like malaria and dengue fever, not Chagas disease. Tsetse flies (C) are known for transmitting African trypanosomiasis (sleeping sickness), not Chagas disease. Cockroaches (D) are not known to transmit Chagas disease.
A stool sample from a patient with chronic diarrhea revealed cysts with four nuclei. What is the most likely causative agent?
- A. Entamoeba histolytica
- B. Giardia lamblia
- C. Balantidium coli
- D. Trichomonas hominis
Correct Answer: A
Rationale: The correct answer is A: Entamoeba histolytica. This is because it is a protozoan parasite known to cause amoebic dysentery, presenting with chronic diarrhea and cysts with four nuclei in the stool sample. Giardia lamblia (B) causes giardiasis with trophozoites and cysts with two nuclei. Balantidium coli (C) is a ciliated parasite causing dysentery with large trophozoites. Trichomonas hominis (D) is a non-pathogenic flagellate often found in the human intestine. Thus, based on the specific characteristics of the cysts and clinical presentation, Entamoeba histolytica is the most likely causative agent.
Subcutaneous mycoses occur predominantly in the:
- A. tropics
- B. deserts
- C. forests of the Northern Hemisphere
- D. Rocky Mountains
Correct Answer: A
Rationale: Subcutaneous mycoses are fungal infections that affect the skin, subcutaneous tissues, and bones. The correct answer is A: tropics, as these infections are more commonly found in warm and humid regions. Fungi that cause subcutaneous mycoses thrive in tropical climates due to the favorable conditions for their growth and transmission. Choices B, C, and D are incorrect because deserts (B) have dry conditions not conducive to fungal growth, forests of the Northern Hemisphere (C) have varying climates that may not support the specific fungi causing subcutaneous mycoses, and the Rocky Mountains (D) are not typically associated with the high humidity required for these infections.