Nokea
Which of the following stains is the most widely used differential stain in hematology laboratories?
- A. Carbolfuchsin stain
- B. Wright’s stain
- C. Ziehl-Neelson stain
- D. Kinyoun stain
Correct Answer: D
Rationale: The correct answer is D: Kinyoun stain. This stain is the most widely used differential stain in hematology labs because it is specifically designed for acid-fast bacteria like Mycobacterium tuberculosis. It differentiates these bacteria from others based on their cell wall composition. Carbolfuchsin stain (A) is used for acid-fast bacteria in microbiology. Wright's stain (B) is used for blood cell morphology. Ziehl-Neelsen stain (C) is also used for acid-fast bacteria but is less commonly used compared to Kinyoun stain in hematology labs.
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Which scientist performed the first successful vaccination against smallpox?
- A. Pasteur
- B. Jenner
- C. Semmelweis
- D. Koch
Correct Answer: B
Rationale: The correct answer is B: Jenner. Edward Jenner is credited with performing the first successful vaccination against smallpox in 1796. He used cowpox virus to inoculate individuals, leading to immunity against smallpox. Jenner's experiment laid the foundation for modern vaccination. Pasteur (A) is known for developing the germ theory of disease. Semmelweis (C) advocated for handwashing to prevent infections. Koch (D) identified the causative agents of several diseases but did not develop the smallpox vaccine.
Poxviruses are DNA viruses that replicate in the Cytoplasm
- A. TRUE
- B. FALSE
- C. Both answers can be correct depending on the given situation
- D. None of the above
Correct Answer: A
Rationale: The correct answer is A: TRUE. Poxviruses are indeed DNA viruses that replicate in the cytoplasm. This is due to their complex structure that allows them to carry out their replication process in the cytoplasm of the host cell. Other choices are incorrect because poxviruses specifically replicate in the cytoplasm and do not require the nucleus for replication, ruling out choice B. Choice C is incorrect because poxviruses consistently replicate in the cytoplasm regardless of the situation. Choice D is incorrect as the correct answer is A.
Which of the following bacteria produce toxins that can lead to foodborne illnesses?
- A. Clostridium botulinum
- B. Salmonella enterica
- C. Escherichia coli
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D. Clostridium botulinum produces botulinum toxin, Salmonella enterica produces salmonella toxin, and certain strains of Escherichia coli produce toxins like shiga toxin. These toxins can cause severe foodborne illnesses. Therefore, all of the above bacteria can produce toxins that lead to foodborne illnesses. Choices A, B, and C alone are incorrect because each of these bacteria individually can produce toxins that lead to foodborne illnesses.
All of the following are beta-lactam antibiotics except
- A. Benzylpenicillin
- B. Monobactam
- C. Cephalosporin
- D. Vancomycin
Correct Answer: D
Rationale: The correct answer is D, Vancomycin, because it is not a beta-lactam antibiotic. Beta-lactam antibiotics contain a beta-lactam ring in their molecular structure, which Vancomycin lacks. Benzylpenicillin, Cephalosporin, and Monobactam all contain the beta-lactam ring, making them beta-lactam antibiotics. Vancomycin belongs to a different class of antibiotics called glycopeptides.
A patient with severe pneumonia had a sputum culture revealing Gram-negative rods that are non-lactose fermenters. What is the most likely causative agent?
- A. Pseudomonas aeruginosa
- B. Escherichia coli
- C. Klebsiella pneumoniae
- D. Enterobacter cloacae
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas aeruginosa. This is because Pseudomonas aeruginosa is a common Gram-negative rod that is a non-lactose fermenter and a common cause of severe pneumonia, especially in immunocompromised individuals. It is also known for its resistance to many antibiotics, making it difficult to treat.
Summary of other choices:
B: Escherichia coli is a lactose fermenter and is not commonly associated with severe pneumonia.
C: Klebsiella pneumoniae is a lactose fermenter and is more commonly associated with pneumonia in alcoholics or debilitated patients.
D: Enterobacter cloacae is a lactose fermenter and is not a common cause of severe pneumonia.