ATI RN
openstax microbiology test bank Questions
Question 1 of 5
(+) ssRNA viruses that have been isolated from birds, cats, dogs, pigs, sheep, cows, and humans and are a major cause of gastroenteritis are the:
Correct Answer: B
Rationale: The correct answer is B: caliciviruses. Caliciviruses are known to be (+) ssRNA viruses that cause gastroenteritis in a wide range of animals, including birds, cats, dogs, pigs, sheep, cows, and humans. These viruses are highly contagious and can spread through contaminated food or water. Rotaviruses (
A) are also a common cause of gastroenteritis, but they are not exclusively isolated from the mentioned animals. Adenoviruses (
C) typically cause respiratory or eye infections, not gastroenteritis. Noroviruses (
D) are also a major cause of gastroenteritis in humans, but they are not commonly found in animals other than humans.
Question 2 of 5
A patient with an abscess had Gram-positive cocci in clusters isolated from a wound culture. The organism was catalase-positive and coagulase-positive. What is the likely causative agent?
Correct Answer: A
Rationale:
Step-by-step rationale:
1. Gram-positive cocci in clusters suggest Staphylococcus or Streptococcus.
2. Catalase-positive and coagulase-positive narrow it down to Staphylococcus.
3. Staphylococcus aureus is catalase-positive and coagulase-positive.
Therefore, the likely causative agent is Staphylococcus aureus.
Summary:
A: Correct - Staphylococcus aureus fits all the characteristics.
B: Incorrect - Staphylococcus epidermidis is catalase-negative and coagulase-negative.
C: Incorrect - Streptococcus pyogenes is catalase-negative and coagulase-negative.
D: Incorrect - Enterococcus faecalis is catalase-negative and coagulase-negative.
Question 3 of 5
A dentist has detected symptoms of parodontosis in a patient. What antiprotozoal drug should be prescribed?
Correct Answer: A
Rationale: The correct answer is A: Metronidazole. Parodontosis is a condition caused by bacterial infection, not protozoal infection. Metronidazole is an effective antibiotic commonly used to treat bacterial infections in the oral cavity, including those associated with parodontosis. Levamisole is an anthelmintic drug used to treat parasitic worm infections, not suitable for parodontosis. Griseofulvin is an antifungal medication used for fungal infections, not indicated for parodontosis. Mykoseptin is not a recognized drug and is likely a distractor.
Therefore, based on the bacterial nature of parodontosis, Metronidazole is the appropriate choice.
Question 4 of 5
A smear of sputum from the patient with suspected lobar pneumonia was stained with the use of the following stains and reagents: solution of gentian violet, Lugol’s solution, 960 alcohol, watermagenta. What staining method was applied in this case?
Correct Answer: A
Rationale: The correct answer is A: Gram staining method. The rationale is as follows:
1. Gentian violet is a primary stain used in the Gram staining procedure to stain the bacterial cells.
2. Lugol's solution is a mordant that helps to fix the crystal violet stain in Gram-positive bacteria.
3. 95% alcohol is used as a decolorizing agent in the Gram staining process to remove the stain from Gram-negative bacteria.
4. Watermagenta is not a standard reagent in the Gram staining method.
Therefore, based on the reagents mentioned, the staining method applied in this case is the Gram staining method.
Other choices are incorrect:
B: Ziehl-Nielsen's - This staining method is used for acid-fast staining, not for lobar pneumonia.
C: Romanovsky - This staining method is used for blood smears, not for bacterial staining in pneumonia.
D: Neisser - This staining method is not commonly used in routine bacterial staining procedures.
Question 5 of 5
A patient's preliminary diagnosis is toxoplasmosis. What material was used for diagnostics of this disease?
Correct Answer: A
Rationale: The correct answer is A: Blood.
Toxoplasmosis is diagnosed through serological tests that detect specific antibodies in the blood. These antibodies indicate exposure to the
Toxoplasma gondii parasite. Feces, urine, and duodenal contents are not typically used for diagnosing toxoplasmosis as the parasite is not commonly found in these samples. Blood is the primary material used as it provides the necessary antibodies for accurate diagnosis.