Microbiology An Introduction 13th Edition Test Bank

Correct Answer: B

Rationale: The correct answer is B: BCG vaccine. Bacille Calmette-Gu�rin (BCG) vaccine is used to prevent tuberculosis, which is caused by a bacterium related to anthrax. BCG vaccine can provide cross-protection against anthrax due to its similar mechanisms of action. STI live vaccine (choice A) is used for sexually transmitted infections, not anthrax. Salk vaccine (choice C) is used for polio, and Sabin's vaccine (choice D) is also for polio, not anthrax. Therefore, BCG vaccine is the most appropriate choice for preventing the spread of anthrax among animals in the countryside.

Correct Answer: D

Rationale: The correct answer is D (All of the above). All three bacteria (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa) produce endotoxins that can lead to septic shock. Endotoxins are part of the outer membrane of Gram-negative bacteria and can trigger a strong immune response, leading to septic shock when released in large amounts. Escherichia coli and Salmonella enterica are common causes of bacterial septic shock, while Pseudomonas aeruginosa is known for its ability to produce endotoxins that contribute to severe infections and septic shock. Therefore, all three choices are correct in this context.

Correct Answer: B

Rationale: The correct answer is B because a supercapsid is a lipoprotein membrane that encloses the nucleocapsid, providing protection to the genetic material inside. This structure is distinct from the capsid which is the protein coat surrounding the nucleic acid. Choice A is incorrect as there is no shell located between the capsid and supercapsid. Choice C is incorrect as it describes the nucleocapsid itself, not the supercapsid. Choice D is incorrect as a protein envelope around the nucleic acid does not specifically refer to a supercapsid.

Correct Answer: A

Rationale: The correct answer is A: Absence of a cell wall. L-form transformation is a phenomenon where the pathogen loses its cell wall, making it resistant to antibiotics like penicillin. The absence of a cell wall allows the pathogen to survive in a hostile environment. Choice B: Absence of flagella is incorrect because flagella are responsible for motility and not directly related to L-form transformation. Choice C: Absence of a capsule is incorrect as the capsule is a protective layer outside the cell wall and not affected by L-form transformation. Choice D: Absence of a spore is incorrect because spores are a dormant form of bacteria and not related to L-form transformation.

Correct Answer: A

Rationale: The correct answer is A: Benzylpenicillin sodium salt. Benzylpenicillin is a beta-lactam antibiotic that inhibits the synthesis of bacterial cell walls by disrupting the formation of murein (peptidoglycan), leading to bacterial cell death. This mechanism specifically targets the causative agent of syphilis, Treponema pallidum. - Choice B: Bijochinol is not a known drug used to treat syphilis. - Choice C: Ciprofloxacin is a fluoroquinolone antibiotic that works by inhibiting bacterial DNA replication and is not the first-line treatment for syphilis. - Choice D: Azithromycin is a macrolide antibiotic that interferes with bacterial protein synthesis and is commonly used to treat other infections but is not the preferred treatment for syphilis.