Microbiology A Systems Approach Test Bank

Correct Answer: A

Rationale: The correct answer is A: Reinfection. This is because the patient fully recovered from the initial syphilis infection after antibiotic therapy, indicating the elimination of the pathogen. Subsequently getting infected again with Treponema pallidum suggests a new exposure to the same pathogen, resulting in a new infection. Recurrence (B) would imply the reactivation of the same infection, which is not the case here. Superinfection (C) refers to a new infection that occurs on top of an existing infection, which is not the scenario described. Secondary infection (D) typically refers to an infection that occurs after an initial infection weakens the immune system, which is not the case in this scenario.

Correct Answer: B

Rationale: The correct answer is B: pharmacokinetics. Pharmacokinetics is the study of drug movement in the body, including absorption, distribution, metabolism, and excretion. It focuses on how the body processes a drug over time. Pharmacodynamics (A) is the study of the effects drugs have on the body. Pharmacotherapeutics (C) involves using drugs to treat diseases. Pharmacy (D) is the practice of preparing and dispensing medications. Pharmacokinetics specifically deals with drug concentrations at different body sites after administration, making it the most appropriate choice for this question.

Correct Answer: D

Rationale: The correct answer is D: All of the above. Escherichia coli, Salmonella enterica, and Pseudomonas aeruginosa are all known to cause urinary tract infections (UTIs) in humans. E. coli is the most common cause of UTIs, accounting for about 80-85% of cases. S. enterica and P. aeruginosa are less common but can still infect the urinary tract under certain circumstances. Therefore, all three bacteria can potentially cause UTIs, making option D the correct choice. Choices A, B, and C are incorrect because they do not cover the full range of bacteria known to cause UTIs.

Correct Answer: A

Rationale: The correct answer is A: Yeast-like fungi of Candida genus. Candida is a common cause of oral thrush/stomatitis, characterized by mucosal lesions with white coating. The presence of large oval Gram-positive cells is indicative of Candida species. Actinomycetes (B) are filamentous bacteria and not oval Gram-positive cells. Streptococci (C) are spherical bacteria, not oval, and are not commonly associated with stomatitis. Oral spirochetes (D) are spiral-shaped bacteria and not oval Gram-positive cells typically seen in Candida infections. Thus, A is the correct choice based on the characteristic morphology and clinical presentation.

Correct Answer: C

Rationale: Rationale for Correct Answer (C - Immunity): 1. Immunity refers to the body's ability to defend against foreign agents. 2. Homeostasis is the state of steady internal conditions, not specifically related to defense. 3. Infection is the invasion and multiplication of pathogens, not the overall defense mechanism. 4. Commensalism is a symbiotic relationship where one organism benefits without harming the other.