Microbiology Chapter 11 Test Bank

Correct Answer: A

Rationale: The most likely diagnosis is A: Leptospirosis. Leptospirosis is caused by the spirochete Leptospira interrogans and is commonly transmitted through contact with water contaminated by animal urine, such as in this case of fishing. The symptoms described match those of leptospirosis, including high fever, headache, muscle pain, jaundice, hemorrhagic rash, and bloody urine. The calf muscle pain is a characteristic symptom of leptospirosis known as "Weil's disease." Yersiniosis (B) typically presents with abdominal symptoms, Salmonellosis (C) with gastrointestinal symptoms, and Brucellosis (D) with flu-like symptoms. Therefore, based on the symptoms and history provided, Leptospirosis is the most likely diagnosis.

Correct Answer: C

Rationale: The correct answer is C because Leptospira cannot be cultivated on blood and chocolate agar. The bacterium requires specialized media such as Ellinghausen-McCullough-Johnson-Harris (EMJH) medium for growth. Blood and chocolate agar do not provide the necessary nutrients for the bacterium's growth. Leptospira is a fastidious organism that has unique culture requirements. Therefore, the statement that Leptospira can be cultivated on blood and chocolate agar is incorrect. The other choices are correct: A - Leptospirosis is an acute infectious disease with a typical geographic distribution, B - Reservoirs of leptospira are different wild and domestic animals, mainly rodents, and D - Doxycycline and penicillins are drugs of choice for the treatment of leptospirosis.

Correct Answer: B

Rationale: Transduction is the transfer of genetic material between bacterial cells with the help of a phage (virus). This process involves a phage infecting a bacterial cell, replicating inside it, and then transferring bacterial DNA along with phage DNA to another bacterial cell. This is different from transformation (choice A) which involves the uptake of naked DNA by a bacterial cell and plasmid transfer (choice C) which involves the transfer of small, circular DNA molecules. Therefore, the correct answer is B because it specifically describes the process of transduction in bacteria, while choices A and C describe different mechanisms of genetic transfer.

Correct Answer: C

Rationale: The correct answer is C: Rickettsia. Rickettsia is a host-dependent bacterium because it requires living cells of a host organism to survive and replicate. This bacterium is an obligate intracellular pathogen, meaning it cannot grow outside of a host cell. A: Mycoplasma and B: Ureaplasma are not host-dependent as they can grow and reproduce in cell-free environments due to possessing their own unique cell wall structures. D: Micrococcus is a free-living bacterium that can survive and reproduce independently without relying on a host organism.

Correct Answer: B

Rationale: The correct answer is B: Reverse transcriptase and protease. Reverse transcriptase converts viral RNA into DNA, a crucial step in viral replication. Protease is responsible for cleaving viral polyproteins into functional proteins. Targeting both enzymes disrupts viral replication. Choice A is incorrect as integrase is not a main target in current therapy. Choice C is incorrect because protease is targeted along with reverse transcriptase, not integrase. Choice D is incorrect as targeting viral glycoproteins is not a main strategy in anti-HIV therapy.