Nokea
Most reliable test for detection of acute hepatitis A infection is
- A. Western blot assay for IgG anti-HAV in serum
- B. ELISA test for IgM anti-HAV in serum and HAV-Ag in stools
- C. ELISA test for IgG anti-HAV in serum
- D. None of the above
Correct Answer: B
Rationale: The correct answer is B: ELISA test for IgM anti-HAV in serum and HAV-Ag in stools. This test is the most reliable for detecting acute hepatitis A infection because IgM antibodies are produced early in the infection, indicating an active infection. Detection of HAV antigen in stools also confirms active viral shedding.
A: Western blot assay for IgG anti-HAV in serum is not the most reliable for acute infection detection as IgG antibodies are produced later in the infection and indicate past exposure or immunity.
C: ELISA test for IgG anti-HAV in serum is not the most reliable for acute infection detection as IgG antibodies are produced later in the infection and indicate past exposure or immunity.
D: None of the above is incorrect as option B is the most appropriate choice for detecting acute hepatitis A infection.
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Which one of all the clostridia that are associated with the disease myonecrosis/gas-gangrene can produce enterotoxin and could be responsible for the development of food intoxications:
- A. Clostridium septicum
- B. Clostridium perfringens
- C. Clostridium histolyticum
- D. Clostridium novyi (oedemmateins)
Correct Answer: B
Rationale: The correct answer is B: Clostridium perfringens. This bacterium is associated with myonecrosis/gas gangrene and can produce enterotoxin causing food intoxication. Clostridium septicum (A) is associated with wound infections but not known for food intoxications. Clostridium histolyticum (C) is not typically associated with myonecrosis or food intoxications. Clostridium novyi (D) is known for causing black disease in sheep and cattle, not food intoxications.
What is the function of bacterial flagella?
- A. Protein synthesis
- B. Motility
- C. Adhesion to surfaces
- D. DNA replication
Correct Answer: B
Rationale: The correct answer is B: Motility. Bacterial flagella function in providing motility to bacteria, allowing them to move towards nutrients or away from harmful substances. Flagella are long, whip-like appendages that rotate to propel the bacteria through their environment.
Incorrect choices:
A: Protein synthesis - Bacterial flagella are not involved in protein synthesis.
C: Adhesion to surfaces - While some bacteria use flagella for attachment, their main function is not adhesion.
D: DNA replication - Flagella do not play a role in DNA replication, which occurs in the bacterial cell's nucleus.
Which of the following bacteria is responsible for causing bacterial meningitis?
- A. Neisseria meningitidis
- B. Haemophilus influenzae
- C. Streptococcus pneumoniae
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D because all three bacteria (Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae) can cause bacterial meningitis. Neisseria meningitidis is a common cause of meningococcal meningitis, Haemophilus influenzae can cause H. influenzae meningitis, and Streptococcus pneumoniae is a leading cause of pneumococcal meningitis. Therefore, all of the above choices are correct. The other choices are incorrect because each of the bacteria listed can independently cause bacterial meningitis, so none of them alone can be the sole correct answer.
In 8 days after a surgery the patient develops tetatus. 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. Sabouraud agar
- B. Endo agar
- C. Hiss medium
- D. Kitt-Tarozzi medium
Correct Answer: D
Rationale: The correct answer is D, Kitt-Tarozzi medium. This medium is specifically designed for the isolation and cultivation of Clostridium tetani, the bacteria responsible for tetanus. The other options, Sabouraud agar, Endo agar, and Hiss medium, are not suitable for the growth of Clostridium tetani. Sabouraud agar is used for fungal cultures, Endo agar is a selective medium for enteric bacteria, and Hiss medium is used for the cultivation of anaerobic bacteria other than Clostridium tetani. Therefore, the Kitt-Tarozzi medium is the most appropriate choice for isolating and identifying the tetanus agent in this scenario.
Which of the following diseases can be transmitted by a tick?
- A. Botulism
- B. Anthrax
- C. Tularemia
- D. MRSA
Correct Answer: C
Rationale: The correct answer is C: Tularemia. Ticks can transmit tularemia, a bacterial infection caused by Francisella tularensis. Ticks pick up the bacteria when feeding on infected animals and can then transmit it to humans through their bites. Botulism (A) is caused by toxins produced by Clostridium botulinum bacteria, not transmitted by ticks. Anthrax (B) is a bacterial infection caused by Bacillus anthracis, typically transmitted through contact with contaminated animal products. MRSA (D) is a bacterial infection caused by Staphylococcus aureus, commonly transmitted through direct contact with infected individuals or contaminated surfaces, not by ticks.