ATI RN
microbiology chapter 14 test bank Questions
Question 1 of 5
A patient with fever, headache, and neck stiffness had cerebrospinal fluid microscopy revealing Gram-negative diplococci. What is the likely causative agent?
Correct Answer: A
Rationale: The correct answer is A: Neisseria meningitidis. This bacterium is a Gram-negative diplococcus commonly associated with meningitis. Neisseria meningitidis is a leading cause of bacterial meningitis in young adults and adolescents. It is known for causing fever, headache, and neck stiffness. The other choices, Streptococcus pneumoniae, Haemophilus influenzae, and Klebsiella pneumoniae, are not typically Gram-negative diplococci and are not commonly associated with the symptoms described. Streptococcus pneumoniae is a Gram-positive coccus, Haemophilus influenzae is a Gram-negative coccobacillus, and Klebsiella pneumoniae is a Gram-negative rod. Therefore, Neisseria meningitidis is the most likely causative agent in this scenario.
Question 2 of 5
The compact structure in which the genome of the bacteria is located is called:
Correct Answer: A
Rationale: The correct answer is A: Nucleoid. The bacterial genome is located in the nucleoid, a region within the bacterial cell where the genetic material is condensed and organized. This structure is not the same as a nucleus found in eukaryotic cells. The other choices (B: Nucleotide and C: ATP) are incorrect because nucleotide refers to a building block of DNA or RNA, and ATP is a molecule used for energy transfer in cells, neither of which specifically houses the bacterial genome. Choice D: None of the above is incorrect as well, as the correct term for the compact structure containing the bacterial genome is the nucleoid.
Question 3 of 5
Which enzyme is one of the most important and constant criteria for pathogenicity of staphylococcus aureus?
Correct Answer: B
Rationale: The correct answer is B: plasma coagulase. This enzyme is essential for the pathogenicity of Staphylococcus aureus as it can convert fibrinogen to fibrin, forming a protective barrier around the bacteria. This helps the bacteria evade the host's immune system. Beta lactamase (A) is not directly related to pathogenicity but rather resistance to beta-lactam antibiotics. Catalase (C) is produced by many bacteria, including Staphylococcus aureus, but it is not a specific indicator of pathogenicity. Choice D is incorrect as plasma coagulase is indeed an important criterion for the pathogenicity of Staphylococcus aureus.
Question 4 of 5
A 23-year old medical student arrives in the student health clinic complaining of difficult in swallowing, sore throat, and chills. Upon examination, she is found to be running a fever and has white patches on her tonsils. A throat swab is positive for streptococcus pyogenes (group A). A diagnosis of acute pharyngitis is made. Her past medical history is unremarkable except an anaphylactic reaction to cefaclor two years ago. Which of the following would be a safe alternative for treating?
Correct Answer: D
Rationale: The correct answer is D: Clindamycin. Clindamycin is a lincosamide antibiotic that is safe to use in patients with a history of anaphylaxis to beta-lactam antibiotics like cefaclor. Clindamycin is effective against streptococcus pyogenes and is a suitable alternative in this case. Amoxicillin (choice A) is a beta-lactam antibiotic similar to cefaclor and may cause a cross-reactive allergic reaction. Meropenem (choice B) is a carbapenem antibiotic and not typically used for acute pharyngitis. Cephalexin (choice C) is a cephalosporin antibiotic and may also cause cross-reactivity in patients with a history of anaphylaxis to cefaclor.
Question 5 of 5
Which of these viruses is a laboratory product?
Correct Answer: C
Rationale: Rationale: 1. Vaccinia is a laboratory product used in smallpox vaccination. 2. Variola is the virus that causes smallpox, not a laboratory product. 3. Monkeypox is a naturally occurring virus, not a laboratory product. 4. Cowpox can be found in nature and is used in vaccine production, but it is not a laboratory product like Vaccinia.