ATI RN
microbiology an introduction 12th edition test bank Questions
Question 1 of 5
The etiological agent of Q-fever is:
Correct Answer: B
Rationale: The correct answer is B: Coxiella burnetii. Q-fever is caused by the bacterium Coxiella burnetii. It is not caused by viruses like Bunyaviridae or Filoviridae. Rickettsia conorii causes Mediterranean spotted fever, not Q-fever. Coxiella burnetii is the only bacterium among the choices known to be the etiological agent of Q-fever.
Question 2 of 5
Bacteriological inspection of disinfection quality at a pharmacy revealed a microorganism in an utility room (in the sink). The microorganism has the following properties: mobile nonspore-forming gram- negative bacteria that form capsular substance, grow well on ordinary nutrient media, secrete the blue-green pigment. This microorganism is most likely to be of the following genus:
Correct Answer: A
Rationale: The correct answer is A: Pseudomonas. Rationale: 1. Mobile nonspore-forming gram-negative bacteria with a capsule substance indicate Pseudomonas. 2. Pseudomonas grow well on ordinary nutrient media, matching the description. 3. The secretion of a blue-green pigment is a characteristic feature of Pseudomonas. 4. Proteus is a gram-negative bacterium but does not match all the given properties. 5. Clostridium is a gram-positive bacterium that forms spores. 6. Shigella is a gram-negative bacterium but does not have the other characteristics mentioned. Therefore, based on the properties described, the most likely genus of the microorganism is Pseudomonas.
Question 3 of 5
The optochin sensitivity test demonstrates:
Correct Answer: B
Rationale: The optochin sensitivity test is used to differentiate Pneumococcal (Streptococcus pneumoniae) from other streptococci. Optochin sensitivity is a characteristic feature of Pneumococcal, as it inhibits its growth. The test involves placing optochin discs on a culture plate and observing the zone of inhibition around the disc for Pneumococcal. Neisseria gonorrhoeae, Staphylococci, and Group A streptococci do not exhibit optochin sensitivity, making them incorrect choices. In summary, the optochin sensitivity test is specific to Pneumococcal, making choice B the correct answer.
Question 4 of 5
A patient being treated for tuberculosis is suffering from hearing deterioration. What drug causes this complication?
Correct Answer: A
Rationale: The correct answer is A: Streptomycin. Streptomycin is an aminoglycoside antibiotic used to treat tuberculosis that can cause hearing loss as a side effect. It is known to damage the cochlear and vestibular organs in the inner ear. The other choices, B: Isoniazid, C: Rifampicin, and D: Ethionamide, are not associated with causing hearing deterioration as a side effect. Isoniazid can rarely cause peripheral neuropathy, Rifampicin can lead to hepatotoxicity, and Ethionamide may cause gastrointestinal disturbances, but none of these drugs are known to specifically cause hearing loss.
Question 5 of 5
The specific binding of HIV to the CD4 surface molecules of the target cells is brought about by:
Correct Answer: A
Rationale: The correct answer is A: Gp120. Gp120 is a glycoprotein on the surface of the HIV virus that specifically binds to the CD4 receptor on target cells. This binding is essential for the virus to enter the host cell and initiate the infection process. Gp41 is another glycoprotein on the virus that helps with membrane fusion, not binding to CD4. Gp32 and Gp55 are not involved in the specific binding of HIV to CD4 molecules. So, A is correct as it directly plays a key role in the initial attachment of HIV to target cells.