microbiology chapter 14 test bank

microbiology chapter 14 test bank Related

Review microbiology chapter 14 test bank related questions and content

Gram-negative diplococci were isolated from a urethral discharge in a male patient with painful urination. What is the causative agent?

  • A. Neisseria gonorrhoeae
  • B. Escherichia coli
  • C. Proteus vulgaris
  • D. Klebsiella pneumoniae
Correct Answer: A

Rationale: The correct answer is A: Neisseria gonorrhoeae. This bacterium is a gram-negative diplococci commonly associated with gonorrhea, which presents with symptoms like painful urination. Neisseria gonorrhoeae is known to infect the urethra in males. Escherichia coli, Proteus vulgaris, and Klebsiella pneumoniae are all gram-negative bacteria, but they are not typically associated with urethral discharge or gonorrhea. E. coli is commonly associated with urinary tract infections, Proteus vulgaris with wound infections, and Klebsiella pneumoniae with pneumonia and other respiratory infections. Therefore, based on the patient's symptoms and the characteristics of the bacteria, Neisseria gonorrhoeae is the most appropriate causative agent in this case.

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Which of the following infectious disease is considered a newly emerging disease?

  • A. Hantavirus
  • B. Malaria
  • C. Tuberculosis
  • D. Chlamydia
Correct Answer: A

Rationale: The correct answer is A: Hantavirus. Hantavirus is considered a newly emerging disease because it was first identified in the late 20th century. It is transmitted to humans through rodents and can lead to severe respiratory illness. Malaria, Tuberculosis, and Chlamydia are not considered newly emerging diseases as they have been known for centuries and continue to be prevalent worldwide. Therefore, based on the timeline of discovery and emergence, Hantavirus is the most recent infectious disease among the options provided.

Infections of the reproductive tract resulting from the introduction of microorganisms through a medical procedure are called:

  • A. chronic infections
  • B. endogenous infections
  • C. systemic infections
  • D. iatrogenic infections
Correct Answer: D

Rationale: The correct answer is D: iatrogenic infections. Iatrogenic infections refer to infections caused by medical or surgical treatment, including procedures that introduce microorganisms into the body. In this case, infections of the reproductive tract caused by medical procedures fall under this category.

A: Chronic infections do not specifically refer to infections caused by medical procedures.
B: Endogenous infections arise from organisms already present in or on the body, not introduced through medical procedures.
C: Systemic infections affect the entire body, not specific to infections caused by medical procedures.

Therefore, the term "iatrogenic infections" is the most appropriate choice in this context.

Nigrosin is a stain used in:

  • A. simple staining
  • B. gram staining
  • C. negative staining
  • D. acid-fast staining
Correct Answer: C

Rationale: Nigrosin is used in negative staining, where the background is stained instead of the cells themselves. This technique helps highlight the morphology and structure of cells that may be damaged by traditional staining methods. Nigrosin is negatively charged and repels the negatively charged bacterial cells, resulting in a clear halo around the cells. This process is particularly useful for observing capsules and determining cell size and shape. The other options are incorrect because simple staining uses a single dye to color the entire cell, gram staining involves a series of dyes to differentiate between gram-positive and gram-negative bacteria, and acid-fast staining is used to detect acid-fast organisms like Mycobacterium.

Which of the following is a disease caused by a protozoan?

  • A. Cat scratch disease
  • B. Toxoplasmosis
  • C. Relapsing fever
  • D. Plague
Correct Answer: B

Rationale: The correct answer is B: Toxoplasmosis. Toxoplasmosis is caused by the protozoan Toxoplasma gondii. The rationale for this is that protozoa are single-celled organisms that can cause diseases in humans. Cat scratch disease (A) is caused by a bacterium, Bartonella henselae. Relapsing fever (C) is caused by the bacterium Borrelia recurrentis. Plague (D) is caused by the bacterium Yersinia pestis. Therefore, the only choice caused by a protozoan is toxoplasmosis, making it the correct answer.

Bacillus intoxication is caused by:

  • A. Bacillus subtilis
  • B. Bacillus thuringiensis
  • C. Bacillus anthracis
  • D. Bacillus cereus
Correct Answer: D

Rationale: The correct answer is D: Bacillus cereus. Bacillus intoxication is typically caused by Bacillus cereus, which is a common foodborne pathogen. This bacterium produces toxins that can lead to gastrointestinal illness when ingested. Bacillus subtilis (A) and Bacillus thuringiensis (B) are not known to cause intoxication in humans. Bacillus anthracis (C) causes anthrax, not intoxication. Therefore, Bacillus cereus is the correct choice for Bacillus intoxication.

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