ATI RN
medical microbiology test bank Questions
Question 1 of 9
RNA viruses belong to which of the following types according to the Baltimore classification system?
Correct Answer: D
Rationale: The correct answer is D: III, IV, V. 1. RNA viruses belong to Group III of the Baltimore classification system because their genetic material is single-stranded RNA. 2. They are also categorized under Group IV as they use reverse transcriptase to replicate their genetic material. 3. Finally, RNA viruses fall under Group V as they have an envelope derived from the host cell membrane. Therefore, options A, B, and C are incorrect as they do not include all the correct groups that RNA viruses belong to according to the Baltimore classification system.
Question 2 of 9
Saddle nose is characteristic of which of the following congenital infections?
Correct Answer: A
Rationale: Saddle nose is a condition where the bridge of the nose collapses, a characteristic feature of congenital syphilis. This occurs due to inflammation and destruction of cartilage. Syphilis is caused by the bacterium Treponema pallidum. CMV, Rubella, and Toxoplasmosis do not typically cause saddle nose. CMV can result in hearing loss, Rubella can lead to cataracts and heart defects, and Toxoplasmosis may cause hydrocephalus or chorioretinitis.
Question 3 of 9
Bacterial spores are resistant to harsh conditions due to:
Correct Answer: B
Rationale: The correct answer is B because the presence of calcium dipicolinate in bacterial spores helps protect their DNA from damage under harsh conditions. Calcium dipicolinate acts as a stabilizer, preserving the spore structure. Choice A is incorrect as bacterial spores have a tough protein coat, not a lipid-rich membrane. Choice C is incorrect as bacterial spores have very low metabolic activity. Choice D is incorrect as bacterial spores have low water content to prevent damage during harsh conditions.
Question 4 of 9
Among public catering workers examined by doctors of sanitary and epidemiologic station often occur asymptomatic parasite carriers. This means that a healthy person carries cysts that infect other people. Such parasitizing is possible for the following causative agent:
Correct Answer: A
Rationale: Rationale: 1. Dysenteric amoeba (Choice A) is the correct answer because it can exist asymptomatically in carriers and be transmitted through cysts. 2. Malarial plasmodium (Choice B) causes malaria, not carried asymptomatically in cysts. 3. Intestinal trichomonad (Choice C) causes trichomoniasis, not carried asymptomatically in cysts. 4. Dermatotropic leishmania (Choice D) causes skin lesions, not carried asymptomatically in cysts.
Question 5 of 9
Which bacteria produce a toxin that causes botulism?
Correct Answer: B
Rationale: The correct answer is B: Clostridium botulinum. This bacterium produces the botulinum toxin, which causes botulism by blocking nerve functions. Clostridium tetani causes tetanus, not botulism. Staphylococcus aureus produces toxins that cause food poisoning, not botulism. Bacillus anthracis causes anthrax, not botulism. Therefore, the correct choice is Clostridium botulinum because it is the specific bacterium responsible for producing the toxin that leads to botulism.
Question 6 of 9
2 weeks since the blood transfusion a recepient has developed fever. What protozoal disease can it be?
Correct Answer: B
Rationale: The correct answer is B: Malaria. Fever developing 2 weeks post-blood transfusion is characteristic of malaria due to the incubation period of the parasite. Trypanosomiasis presents earlier, amebiasis usually causes GI symptoms, and toxoplasmosis typically manifests with flu-like symptoms. Malaria is the most likely cause based on the timing and clinical presentation.
Question 7 of 9
A 25-year-old woman is complaining of burning and painful urination. The microbiological analysis detects significant bacterial growth only on blood agar and it is without hemolysis. Gram-positive cocci are observed on microscopic slides. Which bacterium is the most probable cause?
Correct Answer: B
Rationale: The correct answer is Staphylococcus saprophyticus (choice B). This bacterium is a common cause of urinary tract infections in young women. It typically grows on blood agar without hemolysis and appears as Gram-positive cocci under the microscope. Proteus mirabilis (choice A) is known for urease production, causing alkaline urine. Staphylococcus aureus (choice C) is a common cause of skin and soft tissue infections, not urinary tract infections. Pseudomonas aeruginosa (choice D) is an opportunistic pathogen often seen in nosocomial infections, not typically associated with urinary tract infections in healthy individuals.
Question 8 of 9
Which ones of the following symptoms are not typical of botulism:
Correct Answer: D
Rationale: The correct answer is D. Botulism typically presents with symptoms such as dry mouth, difficulty swallowing, blurred vision, diplopia, and descending flaccid paralysis. Chills, fever, and loss of consciousness are not typical of botulism. Botulism is caused by a neurotoxin produced by Clostridium botulinum bacteria, which affects the nervous system leading to muscle weakness and paralysis, not fever or altered consciousness. Therefore, choice D is the correct answer.
Question 9 of 9
Which bacteria is responsible for causing the disease known as syphilis?
Correct Answer: A
Rationale: The correct answer is A: Treponema pallidum. This bacterium is responsible for causing syphilis due to its unique spiral shape and ability to penetrate mucous membranes. It is transmitted through sexual contact or from mother to fetus. Neisseria gonorrhoeae causes gonorrhea, Chlamydia trachomatis causes chlamydia, and Escherichia coli is a common bacterium in the gastrointestinal tract. Syphilis is distinct due to its characteristic symptoms and stages, making Treponema pallidum the correct choice.