free microbiology test bank questions pdf

Correct Answer: C

Rationale: The correct answer is C: Corynebacterium diphtheriae. This bacterium causes diphtheria, a disease characterized by a pseudomembrane in the throat. This pseudomembrane is a result of the bacterial exotoxins causing inflammation and necrosis of the throat tissues. Clostridium tetani (A) causes tetanus, characterized by muscle stiffness, not a pseudomembrane in the throat. Bordetella pertussis (B) causes whooping cough, with symptoms of severe coughing fits but no pseudomembrane. Streptococcus pyogenes (D) causes strep throat, but does not produce a pseudomembrane.

Correct Answer: A

Rationale: The correct answer is A: Kitt-Tarozzi. This medium contains blood and hemin, which are essential nutrients for the growth of anaerobes. Blood provides a source of iron, while hemin stimulates the growth of anaerobes. This combination creates an environment conducive for the isolation and identification of anaerobic organisms. B: Endo and C: Roux are selective media primarily used for the isolation of gram-negative bacteria and not specifically designed for anaerobes. D: Sabouraud's is a medium used for the cultivation of fungi, not anaerobes. In summary, Kitt-Tarozzi is the correct choice due to its specific nutrient composition that supports the growth of anaerobes, unlike the other options which are not suitable for this purpose.

Correct Answer: D

Rationale: The correct answer is D: rectum. Pinworms typically inhabit the rectum area in humans, where they lay their eggs. This is because the female pinworm migrates to the rectum at night to deposit her eggs near the anus. Other choices are incorrect because pinworms do not reside in the duodenum (A), ileum (B), or transverse colon (C) as their primary location is in the lower gastrointestinal tract near the anus.

Correct Answer: C

Rationale: Rationale for choice C (Strep. pneumoniae): 1. Strep. pneumoniae is a common cause of bacterial meningitis. 2. It is a leading pathogen responsible for meningitis in adults and children. 3. It can invade the bloodstream and reach the meninges, causing inflammation. 4. Treatment guidelines often include antibiotics effective against Strep. pneumoniae. Summary of why other choices are incorrect: A. Staph. aureus is not a common cause of meningitis. B. Strep. pyogenes typically causes streptococcal infections but not meningitis. D. "None of the above" is incorrect as Strep. pneumoniae can cause meningitis.

Correct Answer: B

Rationale: The correct answer is B: Orthomyxovirus type 1. Family Reoviridae includes Orthoreovirus types 1, 2, and 3. Orthomyxovirus belongs to a different family, Orthomyxoviridae. Therefore, B is the correct answer. Orthoreovirus types 1, 2, and 3 are part of the Reoviridae family. Choice A, C, and D are incorrect because they are all part of the Reoviridae family which includes Orthoreoviruses.