Nokea
Capsuliferous bacteria has been detected during microbiological inspection of crude drugs. What method of staining has been used to detect capsules?
- A. Burri-Gins
- B. Ziehl-Neelsen
- C. Neisser
- D. Gram
Correct Answer: A
Rationale: The correct answer is A: Burri-Gins. This staining method specifically targets the detection of capsules in bacteria. It involves staining the capsules with crystal violet and the background with safranin. This staining technique helps visualize the capsules as a distinct halo around the bacteria.
Summary:
- Choice B (Ziehl-Neelsen) is used for acid-fast staining to detect Mycobacterium species.
- Choice C (Neisser) is used for staining Neisseria species.
- Choice D (Gram) is a common staining method used to differentiate bacteria based on cell wall composition (Gram-positive and Gram-negative), but it does not specifically target capsules.
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Microscopic examination of a smear from a patient with gas gangrene revealed Gram-positive rods producing spores. What microorganism was identified?
- A. Clostridium perfringens
- B. Clostridium tetani
- C. Bacillus anthracis
- D. Clostridium botulinum
Correct Answer: A
Rationale: The correct answer is A: Clostridium perfringens. Gas gangrene is caused by Clostridium perfringens, a Gram-positive rod bacterium that produces spores. This bacterium is anaerobic and commonly found in soil, where it forms spores that can survive harsh conditions. Clostridium tetani causes tetanus, not gas gangrene. Bacillus anthracis causes anthrax, not gas gangrene. Clostridium botulinum causes botulism, not gas gangrene. Therefore, based on the characteristics of the microorganism described in the question, Clostridium perfringens is the correct identification.
The cleanup of various industrial wastes by living organisms is referred to as __________.
- A. biomining
- B. biosynthesis
- C. bioremediation
- D. bioengineering
Correct Answer: C
Rationale: The correct answer is C: bioremediation. Bioremediation is the process of using living organisms to clean up environmental pollution, including industrial wastes. This method utilizes microorganisms, plants, or fungi to break down or neutralize pollutants. Biomining (A) is the process of extracting valuable metals from ores using biological organisms. Biosynthesis (B) refers to the production of complex molecules by living organisms. Bioengineering (D) involves the application of engineering principles to biological systems, not specifically related to cleaning up industrial wastes. Therefore, the most appropriate term for the cleanup of industrial wastes by living organisms is bioremediation.
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.
Which bacteria are known to produce an endotoxin that can cause septic shock?
- A. Salmonella enterica
- B. Escherichia coli
- C. Pseudomonas aeruginosa
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D because all three bacteria (Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa) are known to produce endotoxins, specifically lipopolysaccharides in their cell walls. Endotoxins are released upon bacterial cell death and can trigger an immune response, leading to septic shock. Salmonella and E. coli are common causes of bacterial infections, while Pseudomonas is associated with nosocomial infections. Therefore, all of the above choices are correct in terms of producing endotoxins that can cause septic shock. Choices A, B, and C are incorrect individually because they do not encompass all the bacteria known to produce endotoxins that can lead to septic shock.
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.