Nokea
Which of the following is not considered to be a vehicle transmission?
- A. Airborne
- B. Insect
- C. Foodborne
- D. Bodily fluid
Correct Answer: B
Rationale: The correct answer is B: Insect. A vehicle transmission refers to the mode by which a disease spreads from one host to another. Insects can transmit diseases, making them a vehicle for transmission. Airborne, foodborne, and bodily fluid transmissions are well-known modes of disease spread, while insects are also known vectors for diseases like malaria and Zika.
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Bacteria that require low oxygen concentrations for growth are called:
- A. Facultative anaerobes
- B. Obligate aerobes
- C. Microaerophiles
- D. Obligate anaerobes
Correct Answer: C
Rationale: The correct answer is C: Microaerophiles. These bacteria grow best in environments with low oxygen levels. They require oxygen for respiration but at lower concentrations than what is present in the atmosphere. This allows them to thrive in conditions where oxygen is limited but not completely absent.
A: Facultative anaerobes can grow in both the presence and absence of oxygen.
B: Obligate aerobes require oxygen for growth.
D: Obligate anaerobes cannot survive in the presence of oxygen and typically grow in anaerobic environments.
In summary, microaerophiles are the correct choice as they specifically thrive in low oxygen environments, distinguishing them from the other options.
Specify the most commonly used parameters for autoclaving sterilization:
- A. 1.0 atm., 120º C, 15-20min
- B. 1.0 atm., 130º C, 10 hours
- C. 1.5 atm., 135º C, 5min
- D. 1.0 atm., 160º C, 1 hour
Correct Answer: A
Rationale: The correct answer is A because it specifies the commonly used parameters for autoclaving sterilization: 1.0 atm pressure, 120º C temperature, and 15-20 minutes duration. This combination ensures effective sterilization by providing the necessary heat and pressure for killing microorganisms.
Rationale:
1. Pressure of 1.0 atm: Standard atmospheric pressure commonly used in autoclaving.
2. Temperature of 120º C: Optimal temperature for sterilization without causing damage to heat-sensitive materials.
3. Duration of 15-20 minutes: Time required for heat and pressure to penetrate and kill microorganisms effectively.
Summary of Incorrect Choices:
B: Incorrect temperature and duration, too high and long, may damage materials.
C: Incorrect pressure and temperature, higher pressure and temperature not commonly used.
D: Incorrect temperature, too high, can damage materials, and duration is longer than necessary.
Which of the following bacteria can cause meningitis?
- A. Neisseria meningitidis
- B. Haemophilus influenzae
- C. Streptococcus pneumoniae
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae are all bacteria known to cause meningitis. Neisseria meningitidis is a common cause of bacterial meningitis in young adults, Haemophilus influenzae type b is a common cause in children, and Streptococcus pneumoniae is a leading cause in adults and the elderly. Therefore, all three bacteria can potentially cause meningitis depending on the age group and other factors. The other choices are incorrect because each of the bacteria listed can cause meningitis, so selecting only one of them would be incorrect.
Granulomas containing lymphocytes and macrophages were detected during analysis of skin biopsy material. Among macrophages there are large cells with fat inclusions, which contain microorganisms in spheric packages (Virchow's cells). The following disease is based on the described type of hypersensitivity:
- A. Leprosy
- B. Syphilis
- C. Tuberculosis
- D. Rhinoscleroma
Correct Answer: C
Rationale: The correct answer is C: Tuberculosis. Granulomas with lymphocytes and macrophages containing Virchow's cells (large cells with fat inclusions containing microorganisms) are classic findings in tuberculosis. Leprosy (A) typically presents with granulomas but with different histopathological features. Syphilis (B) does not usually form granulomas in the skin. Rhinoscleroma (D) is a chronic bacterial infection characterized by nodular lesions but does not typically involve Virchow's cells as seen in tuberculosis.
Bacteria that use oxygen, but only at low concentration, are classified as:
- A. obligate aerobes
- B. microaerophiles
- C. obligate anaerobes
- D. aerotolerant anaerobes
Correct Answer: B
Rationale: The correct answer is B: microaerophiles. These bacteria require oxygen to grow, but only at low concentrations as higher levels can be toxic. They possess enzymes to deal with reactive oxygen species. Obligate aerobes (A) require oxygen for growth, obligate anaerobes (C) cannot survive in the presence of oxygen, and aerotolerant anaerobes (D) can tolerate oxygen but do not use it for growth.