microbiology an evolving science test bank -Nurselytic

Correct Answer: A

Rationale: The correct answer is A: Lassa virus. The rationale is as follows:
1. Lassa virus is a member of the Arenaviridae family, known for causing Lassa fever.
2. Arenaviridae family includes viruses with a segmented genome and are transmitted through rodents.
3. Crimean-Congo hemorrhagic fever virus (
Choice
B) belongs to the Bunyaviridae family, not Arenaviridae.
4. Rabies virus (
Choice
C) belongs to the Rhabdoviridae family, not Arenaviridae.
5. Epstein-Barr virus (
Choice
D) belongs to the Herpesviridae family, not Arenaviridae.
In summary, Lassa virus is the correct choice as it aligns with the characteristics of the Arenaviridae family, while the other choices belong to different virus families.

Correct Answer: B

Rationale: The correct answer is B: colonization. E. Coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa in the pharynx indicate colonization rather than being part of the normal resident flora. Colonization refers to the presence of these bacteria on body surfaces without causing harm. They are not considered normal flora in the pharynx but rather transient or opportunistic pathogens.
Choice A is incorrect because these bacteria are not part of the normal resident flora of the pharynx.
Choice C is incorrect as it implies that these bacteria are both normal flora and colonization, which is not accurate.
Choice D is incorrect as there is evidence of bacterial presence, indicating colonization.

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:
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Choice B (Ziehl-Neelsen) is used for acid-fast staining to detect Mycobacterium species.
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Choice C (Neisser) is used for staining Neisseria species.
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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.

Correct Answer: C

Rationale: Plasmids often carry antibiotic resistance genes, making choice C correct. Plasmids are circular DNA structures, not linear (
A). They are found in both gram-positive and gram-negative bacteria, not exclusively in gram-positive bacteria (
B). Plasmids are separate from the bacterial chromosome, not part of it (
D).
Therefore, choice C is the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Clostridium tetani. This bacterium is responsible for causing tetanus due to its production of tetanus toxin. Clostridium perfringens (
B) causes gas gangrene, Streptococcus pyogenes (
C) causes strep throat and skin infections, and Escherichia coli (
D) is a common gut bacteria that can cause food poisoning but not tetanus.