Microbiology An Introduction Tortora Test Bank

Correct Answer: C

Rationale: The correct answer is C: Actinomycosis. Actinomycosis is a chronic suppurative bacterial infection caused by Actinomyces species, which form sulfur granules in purulent masses surrounded by dense fibrous tissue. In this case, the presence of fungal druses, plasma cells, xanthoma cells, and macrophages in the histological examination is characteristic of actinomycosis. The clinical presentation of skin redness, swelling, and abscess formation in the neck area also aligns with actinomycosis. Choice A: Syphilis is caused by Treponema pallidum, presenting with a painless chancre at the site of infection, not skin redness and swelling in the neck area. Choice B: Carbuncle is a bacterial skin infection involving a group of hair follicles, typically on the back of the neck, not characterized by fungal druses or sulfur granules. Choice D: Leprosy

Correct Answer: B

Rationale: I'm sorry, but there seems to be a mistake in the question provided. The correct answer should be A: smallpox. Variola virus indeed causes smallpox, not jock itch. Smallpox is a highly contagious disease characterized by fever and rash, while jock itch, ringworm, and shingles are caused by different pathogens and have distinct symptoms.

Correct Answer: A

Rationale: Step-by-step rationale: 1. Family Retroviridae is known for having a single-stranded RNA genome. 2. The (-) sign indicates that the RNA strand is negative-sense. 3. Therefore, the correct answer A, "Their capsid consists of two copies of ssRNA(-)," is accurate. Summary: - Choice B is incorrect because Retroviridae have simple type of symmetry. - Choice C is incorrect as Retroviridae are not enveloped viruses. - Choice D is incorrect because Retroviridae are enveloped viruses.

Correct Answer: D

Rationale: The correct answer is D: Exanthematous rash. Erythema infectiosum, also known as fifth disease, is characterized by a distinctive rash on the cheeks that looks like a "slapped cheek." This rash then spreads to the rest of the body, resulting in a lace-like rash (exanthem). Swelling of salivary glands (choice A) is not a typical symptom of erythema infectiosum. Diarrhea (choice B) and hepatitis (choice C) are also not associated with this condition. Therefore, the most characteristic clinical symptom of erythema infectiosum is the exanthematous rash.

Correct Answer: B

Rationale: The correct answer is B: to sequester iron from the environment. Siderophores are molecules produced by bacteria to chelate and acquire iron, an essential nutrient for their growth and survival. By sequestering iron, bacteria can compete with host cells and other microbes for this vital resource. This enhances their ability to thrive and establish infections. Choices A, C, and D are incorrect because siderophores do not directly enhance antibiotic resistance, form capsules, or perform oxidative phosphorylation. These functions are unrelated to the primary role of siderophores in iron acquisition.