Microbiology A Systems Approach Test Bank

Correct Answer: C

Rationale: Rationale: 1. The presence of ulcers in animals suggests a parasitic infection. 2. Mosquitoes as carriers indicate a protozoan transmitted through insect bites. 3. Among the choices, Plasmodium falciparum causes malaria transmitted by mosquitoes. 4. Leishmania tropica major causes cutaneous leishmaniasis, not ulcers. 5. Balantidium coli causes intestinal infections, not skin ulcers. 6. Trypanosoma cruzi causes Chagas disease, not skin ulcers.

Correct Answer: D

Rationale: The correct answer is D: Adenovirus. Adenovirus commonly causes acute febrile pharyngitis and pharyngoconjunctival fever. Adenovirus is known to cause respiratory infections and can present with symptoms such as sore throat, fever, and conjunctivitis. VZV (Varicella-Zoster Virus) causes chickenpox and shingles, not these specific symptoms. Measles virus causes a systemic illness with characteristic rash, not typically pharyngitis. Rubella virus causes a mild febrile illness with rash, but not pharyngitis. Therefore, based on the clinical presentation described, adenovirus is the most likely cause.

Correct Answer: A

Rationale: The correct answer is A: Break down antibiotics like penicillin. Beta-lactamase is an enzyme produced by bacteria to inactivate beta-lactam antibiotics like penicillin by breaking the beta-lactam ring. This mechanism helps bacteria resist the antibiotic's effects. The other choices are incorrect because beta-lactamase does not enhance protein synthesis, facilitate DNA replication, or transport nutrients. It specifically targets and deactivates beta-lactam antibiotics, making choice A the most appropriate answer.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae are all bacteria associated with causing bacterial meningitis. Neisseria meningitidis commonly causes meningococcal meningitis, Haemophilus influenzae can cause H. influenzae type b meningitis, and Streptococcus pneumoniae is a common cause of pneumococcal meningitis. Therefore, all three bacteria are known to be causative agents of bacterial meningitis. The other choices are incorrect as they do not encompass all the bacteria associated with causing bacterial meningitis.

Correct Answer: C

Rationale: The correct answer is C: 10% of the infected men have no symptoms. This is true because gonorrhea can be asymptomatic in some individuals, leading to undiagnosed cases. Testicular pain and epididymal tenderness (choice A) are not typical symptoms of gonorrhea in men. Painful urination (choice B) may or may not be present. Purulent discharge (choice D) is a common symptom but not always present. Therefore, choice C is the most accurate statement regarding gonorrhea symptoms in men.