Nokea
Genus Rickettsia representatives are characterized by:
- A. Gram-positive cell wall
- B. High resistance to external environment factors
- C. Intracellular parasitism
- D. None of the above
Correct Answer: C
Rationale: The correct answer is C: Intracellular parasitism. Genus Rickettsia representatives are known for their ability to live and replicate inside the host's cells, making them obligate intracellular parasites. This characteristic distinguishes them from other bacteria.
A: Gram-positive cell wall is incorrect because Rickettsia have a gram-negative cell wall.
B: High resistance to external environment factors is incorrect because Rickettsia are sensitive to environmental conditions and require specific host cells for survival.
D: None of the above is incorrect because Rickettsia do exhibit the characteristic of intracellular parasitism.
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A 23-year-old man developed a perforation in his hard palate, a dense formation with clear margins was detected in this area. After a surgery, microscopy of excised formation shows there a large focus of caseous necrosis surrounded with a granulation tissue with endovasculitis and a cellular infiltration consisting of lymphocytes and epithelioid cells with predominance of plasma cells. What is the most likely disease in this case?
- A. Syphilis
- B. Tuberculosis
- C. Leprosy
- D. Scleroma
Correct Answer: B
Rationale: The correct answer is B: Tuberculosis. The case describes a man with a perforation in the hard palate and features of caseous necrosis with granulation tissue, endovasculitis, and a cellular infiltration mainly of lymphocytes, epithelioid cells, and plasma cells. These findings are classic for tuberculosis infection, commonly seen in extrapulmonary sites like the oral cavity. Syphilis (choice A) typically presents with a painless ulcer and different histopathological features. Leprosy (choice C) presents with granulomas containing foamy macrophages. Scleroma (choice D) is caused by Klebsiella rhinoscleromatis and presents with chronic granulomatous inflammation.
Which is correct for bacterial growth?
- A. Most of the bacteria can grow in absence or in presence of oxygen
- B. All bacteria grow in absence of oxygen
- C. All bacteria are microaerophiles
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A because most bacteria can grow in both the presence and absence of oxygen. Some bacteria are aerobic and require oxygen for growth, while others are anaerobic and can grow in the absence of oxygen. Choice B is incorrect because not all bacteria grow in the absence of oxygen. Choice C is incorrect because not all bacteria are microaerophiles, which are bacteria that require a low level of oxygen for growth. Choice D is incorrect because most bacteria exhibit flexibility in their oxygen requirements.
Clinical symptom, typical for erythema infectiosum is:
- A. Swelling of salivary glands
- B. Diarrhea
- C. Hepatitis
- D. Exanthematous rash
Correct Answer: D
Rationale: The correct answer is D: Exanthematous rash. Erythema infectiosum, also known as fifth disease, is characterized by a distinctive rash on the cheeks that looks like a "slapped cheek." This rash then spreads to the rest of the body, resulting in a lace-like rash (exanthem). Swelling of salivary glands (choice A) is not a typical symptom of erythema infectiosum. Diarrhea (choice B) and hepatitis (choice C) are also not associated with this condition. Therefore, the most characteristic clinical symptom of erythema infectiosum is the exanthematous rash.
In the morning a patient had nausea, abdominal discomfort, single vomiting, dry mouth. In the evening, the patient presented with the increasing general weakness, double vision, difficult swallowing of solid food. Objectively: ptosis, mydriasis, anisocoria, absence of gag and pharyngeal reflex, dry mucous membranes. The previous evening the patient had dinner with canned food and alcohol. What is the presumptive diagnosis?
- A. Botulism
- B. Poliomyelitis
- C. Food toxicoinfection
- D. Acute ischemic stroke
Correct Answer: A
Rationale: The correct answer is A: Botulism. The symptoms described, such as ptosis, mydriasis, anisocoria, dry mouth, and absent gag reflex, are classic signs of botulism. Botulism is caused by the bacterium Clostridium botulinum, commonly found in improperly preserved canned foods. The progression from gastrointestinal symptoms to neurological symptoms, like double vision and difficulty swallowing, is characteristic of botulism due to the toxin's effect on neuromuscular transmission. Poliomyelitis primarily affects the motor neurons and presents with different symptoms. Food toxicoinfection typically involves gastrointestinal symptoms and does not manifest with the neurological findings seen in this case. Acute ischemic stroke presents with sudden onset neurological deficits due to impaired blood flow to the brain, which is not consistent with the gradual progression of symptoms in this scenario.
A wound swab from a patient with a deep tissue infection revealed Gram-positive rods with terminal spores. What is the most likely causative agent?
- A. Clostridium perfringens
- B. Bacillus anthracis
- C. Clostridium tetani
- D. Bacillus cereus
Correct Answer: A
Rationale: The correct answer is A: Clostridium perfringens. This is because Clostridium perfringens is a Gram-positive rod bacterium that forms terminal spores. It is commonly associated with deep tissue infections and can cause gas gangrene. Bacillus anthracis (B) causes anthrax and does not typically form spores at the terminal end. Clostridium tetani (C) causes tetanus and Bacillus cereus (D) is more commonly associated with food poisoning. In this case, the presence of terminal spores along with the clinical presentation of a deep tissue infection points towards Clostridium perfringens as the most likely causative agent.