microbiology basic and clinical principles test bank

Correct Answer: B

Rationale: The capsule of Bacillus anthracis is made of polypeptide. This is because the capsule is composed of a protein-based material that surrounds the bacterium, providing protection and aiding in its virulence. Polysaccharides, lipids, and the absence of capsules are not characteristic of Bacillus anthracis' capsule structure, making choices A, C, and D incorrect, respectively.

Correct Answer: A

Rationale: The correct answer is A: Pseudomonas aeruginosa. P. aeruginosa is a Gram-negative rod that is oxidase-positive and lactose non-fermenting. The positive oxidase test indicates the presence of cytochrome c oxidase, a characteristic of P. aerugin. E. coli is lactose fermenting. Salmonella and Shigella are also Gram-negative rods, but they are lactose fermenters, unlike the lactose non-fermenting P. aeruginosa.

Correct Answer: D

Rationale: The correct answer is D: Lassa virus. The rationale is as follows: 1. Lassa virus belongs to the family Arenaviridae, known for causing Lassa fever. 2. Rabies virus belongs to the Rhabdoviridae family. 3. Crimean-Congo hemorrhagic fever virus belongs to the Nairoviridae family. 4. Epstein-Barr virus belongs to the Herpesviridae family. In summary, Lassa virus is the correct answer because it is the only virus listed that belongs to the Arenaviridae family.

Correct Answer: D

Rationale: Rationale: 1. Streptococcus pneumoniae is a common cause of bacterial pneumonia. 2. Mycobacterium tuberculosis can cause a type of pneumonia called tuberculosis. 3. Escherichia coli is not typically associated with pneumonia. 4. "All of the above" includes both Streptococcus pneumoniae and Mycobacterium tuberculosis, which are known to cause pneumonia. Therefore, D is the correct answer.

Correct Answer: A

Rationale: The correct answer is A: Vibrios. Vibrios are gram-negative curved bacteria that are motile and do not form spores or capsules. The description of the bacteria in the question fits the characteristics of Vibrios. Vibrios are commonly found in aquatic environments and some species can cause gastrointestinal infections in humans. B: Spirochetes are also gram-negative curved bacteria, but they are spiral-shaped and have unique axial filaments for motility. The description in the question does not match the characteristics of spirochetes. C: Clostridia are gram-positive, spore-forming bacteria. The question specifically states that the bacteria are gram-negative and do not form spores, ruling out Clostridia. D: Corynebacteria are gram-positive, non-spore-forming bacteria. The description in the question does not match the characteristics of Corynebacteria.