ATI RN
microbiology a systems approach test bank Questions
Question 1 of 5
Which of the following bacterial structures has endotoxic activity?
Correct Answer: A
Rationale: The correct answer is A: Lipopolysaccharides. Lipopolysaccharides (LPS) are major components of the outer membrane of Gram-negative bacteria and are known to have endotoxic activity. LPS can trigger a strong immune response leading to inflammation and septic shock.
Choice B, Lipoproteins of Braun, are not known to have endotoxic activity.
Choice C, Protein A, is a surface protein found in Staphylococcus aureus and is not associated with endotoxic activity.
Choice D, None, is incorrect as LPS is indeed a bacterial structure with endotoxic activity.
Question 2 of 5
Infections of the CNS can be caused by:
Correct Answer: D
Rationale: The correct answer is D because all three choices, Clostridium botulinum, Morbillivirus morbillorum, and Clostridium tetani, can cause infections of the CNS. Clostridium botulinum can lead to botulism, affecting the nervous system. Morbillivirus morbillorum can cause measles, which can lead to encephalitis. Clostridium tetani can cause tetanus, affecting the central nervous system.
Therefore, all three choices can cause infections of the CNS.
Choices A, B, and C are incorrect individually because each pathogen can cause CNS infections.
Question 3 of 5
Antibiotics for multiple-resistant microorganisms are:
Correct Answer: D
Rationale: The correct answer is D: Imipenem. Imipenem is a carbapenem antibiotic effective against multiple-resistant microorganisms due to its broad spectrum and resistance to beta-lactamases. It is often used as a last resort for severe infections.
Ampicillin (
A) and Penicillin (
B) are both beta-lactam antibiotics that are less effective against multiple-resistant microorganisms due to widespread resistance mechanisms. Augmentin (
C) is a combination of amoxicillin and clavulanic acid, which may have limited efficacy against certain resistant strains but is not as effective as imipenem for treating infections caused by multiple-resistant microorganisms.
Question 4 of 5
A sputum smear stained by Gram's method revealed Gram-positive cocci in clusters. The patient presented with an abscess. What is the causative agent?
Correct Answer: A
Rationale: The correct answer is A: Staphylococcus aureus. Staphylococcus aureus is a Gram-positive bacterium that commonly presents as cocci in clusters. It is a known causative agent of abscesses due to its ability to produce enzymes and toxins that contribute to tissue destruction. In this case, the presence of Gram-positive cocci in clusters aligns with the characteristic morphology of Staphylococcus aureus.
Summary of incorrect choices:
B: Streptococcus pyogenes is a Gram-positive bacterium that typically presents as cocci in chains, not clusters. It is more commonly associated with pharyngitis and skin infections rather than abscesses.
C: Enterococcus faecalis is a Gram-positive bacterium that typically presents as cocci in pairs or short chains, not clusters. It is more commonly associated with urinary tract infections and endocarditis.
D: Micrococcus luteus is a Gram-positive bacterium that typically presents as t
Question 5 of 5
Which of the following is a preferred mode of transmission of HIV from a mother to a child
Correct Answer: D
Rationale: The correct answer is D because HIV can be transmitted from a mother to a child through multiple modes: during delivery through mixing of blood, during pregnancy through the placenta, and via breastmilk during lactation. Each mode presents a risk of transmission due to the presence of the virus in bodily fluids.
Therefore, all of the above options are preferred modes of transmission for HIV from a mother to a child.
Choices A, B, and C alone do not fully encompass all the possible routes of transmission, making them incorrect.