Nokea
Botulism is a disease caused by the production of a potent neurotoxin by bacteria of the genus:
- A. Staphylococcus
- B. Klebsiella
- C. Salmonella
- D. Clostridium
Correct Answer: D
Rationale: The correct answer is D: Clostridium. Clostridium bacteria produce the neurotoxin responsible for botulism. Clostridium botulinum is specifically known for causing this disease. Staphylococcus (A), Klebsiella (B), and Salmonella (C) do not produce the neurotoxin associated with botulism. Staphylococcus typically causes skin infections, Klebsiella is often associated with pneumonia and urinary tract infections, and Salmonella is known for causing food poisoning. Therefore, the correct answer is Clostridium due to its specific association with botulism.
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A patient with abdominal pain and diarrhea had a stool culture revealing non-lactose-fermenting, Gram-negative rods. What is the most likely causative agent?
- A. Shigella dysenteriae
- B. Salmonella typhi
- C. Escherichia coli
- D. Proteus vulgaris
Correct Answer: A
Rationale: The correct answer is A: Shigella dysenteriae. Shigella causes dysentery, characterized by bloody diarrhea and abdominal pain. Shigella is a non-lactose-fermenting, Gram-negative rod.
B: Salmonella typhi causes typhoid fever, not typically associated with abdominal pain and diarrhea.
C: Escherichia coli, a common gut bacteria, can cause diarrhea but typically ferments lactose.
D: Proteus vulgaris is not a common cause of gastrointestinal infection and is not typically associated with abdominal pain and diarrhea.
On microscopic examination of leftovers of the canned meat eaten by patient with severe food toxicoinfection the following was detected: gram-positive bacilli with subterminal staining defect and configuration alteration of bacilli generally resembling a tennis racket. What agent was detected?
- A. C. botulinum
- B. P. vulgaris
- C. E. coli
- D. S. aureus
Correct Answer: A
Rationale: The correct answer is A: C. botulinum. The description of gram-positive bacilli with subterminal staining defect and tennis racket appearance is characteristic of Clostridium botulinum. The subterminal staining defect indicates the presence of spores, a feature of Clostridium species. The tennis racket appearance refers to the characteristic shape of C. botulinum spores. Choice B, P. vulgaris, is a gram-negative bacterium and doesn't match the description. Choice C, E. coli, is a gram-negative bacillus and doesn't exhibit the subterminal staining defect described. Choice D, S. aureus, is a gram-positive cocci and does not resemble the tennis racket appearance described.
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.
A smear of sputum from the patient with suspected lobar pneumonia was stained with the use of the following stains and reagents: solution of gentian violet, Lugol's solution, 96o alcohol, water-magenta. What staining method was applied in this case?
- A. Gram
- B. Ziehl-Nielsen
- C. Romanovsky
- D. Neisser
Correct Answer: A
Rationale: The correct answer is A: Gram staining method. This method involves staining with gentian violet, followed by Lugol's solution, 96% alcohol decolorization, and counterstaining with safranin or water-magenta. This staining sequence allows for the differentiation of bacteria based on their cell wall composition. In the case of lobar pneumonia, the causative agent is typically a bacterium with a cell wall that retains the crystal violet stain after decolorization with alcohol, indicating a Gram-positive bacterium.
Summary of Incorrect Choices:
B: Ziehl-Nielsen staining is used for acid-fast bacteria like Mycobacterium tuberculosis, not for lobar pneumonia.
C: Romanovsky staining is primarily used in the identification of blood cells and blood parasites, not for bacteria.
D: Neisser staining is not a commonly used staining method in microbiology for bacterial identification.
What microorganisms were accounted for in this case?
- A. All bacteria that have grown on a nutrient medium
- B. Opportunistic pathogenic bacteria
- C. Enteropathogenic bacteria and viruses
- D. Colibacilli
Correct Answer: C
Rationale: The correct answer is C because the case specifically mentions "enteropathogenic bacteria and viruses," indicating a focus on these specific microorganisms. Choice A is too broad and includes all bacteria, which is not specified in the case. Choice B mentions opportunistic pathogenic bacteria, which are not necessarily relevant to the case. Choice D specifies colibacilli, which may or may not be relevant to the case, but it is not as specific as choice C which clearly matches the information provided in the case.