Microbiology Chapter 12 Test Bank

Correct Answer: A

Rationale: The correct answer is A: Antibiotic. Brucellosis is a bacterial infection, and antibiotics are the primary treatment to target and eliminate the bacteria causing the disease. Antibiotics such as doxycycline and rifampin are commonly used for brucellosis treatment. Donor immunoglobulin (B) is not used to treat brucellosis as it is not caused by a deficiency in antibodies. Inactivated therapeutic vaccine (C) is used for prevention, not for treating active infections. Antitoxic serum (D) is used to neutralize toxins produced by bacteria, not to directly kill the bacteria themselves in cases like brucellosis.

Correct Answer: A

Rationale: The correct answer is A: Bacterial endospores. Bacterial endospores have a higher resistance to environmental stresses due to their unique structure, which includes a tough outer layer that protects the spore from harsh conditions such as heat, chemicals, and radiation. This protective layer allows endospores to remain dormant and survive in unfavorable environments until conditions improve. Summary: B: Fungal spores - While fungal spores can also survive in harsh conditions, they are generally not as resistant as bacterial endospores due to differences in their protective structures. C: Enveloped viruses - Enveloped viruses are susceptible to environmental stresses as their lipid envelope can easily be damaged by heat, chemicals, and other factors. D: Vegetative bacterial cells - Vegetative bacterial cells are more susceptible to environmental stresses compared to endospores, as they do not have the same level of protective mechanisms to survive in unfavorable conditions.

Correct Answer: A

Rationale: 1. Vaccination introduces antigens to stimulate immune response. 2. T and B cells are activated to produce memory cells for long-lasting protection. 3. Active immunity develops over time post-vaccination. 4. Choice A is correct as it accurately describes the process and outcomes. 5. Choice B is incorrect as it contradicts the process of active immunity. 6. Choice C is incorrect as the process of active immunity is consistent regardless of the situation. 7. Therefore, the correct answer is A as it aligns with the mechanism and characteristics of artificial active immunity.

Correct Answer: D

Rationale: The correct answer is D: Immunocomplex. In this case, the patient's symptoms of fever, joint pains, rash, and itch along with leukopenia and thrombocytopenia indicate a serum sickness reaction. This is a type III hypersensitivity reaction where antigen-antibody complexes deposit in tissues, leading to inflammation and tissue damage. The symptoms typically occur 1-2 weeks after exposure to the antigen. Anaphylactic reaction (choice A) is immediate and involves IgE antibodies. Cytotoxic reaction (choice B) involves destruction of cells by antibodies. Delayed hypersensitivity (choice C) usually takes 48-72 hours to develop and involves T-cells. Therefore, the correct answer is D as it aligns with the symptoms and timeline of a type III hypersensitivity reaction.

Correct Answer: B

Rationale: The correct answer is B: biofilms. Biofilms are structured communities of microorganisms that adhere to a surface and are embedded in a matrix. This is the most appropriate term as it specifically describes the organization of various species into complex communities on a surface. Colonies (A) refer to groups of cells of the same species, not necessarily multiple species. Ecosystems (C) are broader systems involving interactions between living organisms and their environment. Plagues (D) are outbreaks of disease, not a term used to describe organized microbial communities.