ATI RN
Microbiology An Introduction Tortora Test Bank Questions
Question 1 of 9
Planned mass vaccination of all newborn 5-7 day old children against tuberulosis plays an important role in tuberculosis prevention. In this case the following vaccine is applied:
Correct Answer: A
Rationale: The correct answer is A: BCG (Bacille Calmette-Guerin). BCG is the vaccine used for tuberculosis prevention, not only for newborns but also for older children and adults. BCG helps in protecting against severe forms of tuberculosis in infants. Diphteria and tetanus toxoids and pertussis vaccine (choice B) is for protection against diphtheria, tetanus, and pertussis, not tuberculosis. Diphtheria and tetanus anatoxin vaccine (choice C) provides protection against diphtheria and tetanus, not tuberculosis. Adsorbed diphtheria vaccine (choice D) is specifically for diphtheria, not tuberculosis. Therefore, the correct choice is A as it is the only vaccine related to tuberculosis prevention.
Question 2 of 9
A scolex is a structure found in:
Correct Answer: D
Rationale: The correct answer is D: Ancylostoma duodenale. A scolex is a structure found in tapeworms, not in the other options which are roundworms. Ancylostoma duodenale is a species of hookworm, a type of intestinal parasite that has a distinct scolex with hook-like mouthparts for attachment to the host's intestinal wall. Enterobius vermicularis is a pinworm, Necator americanus is a hookworm species without a scolex, and Ascaris lumbricoides is a roundworm with a cylindrical body lacking a scolex. Therefore, the presence of a scolex specifically points to Ancylostoma duodenale.
Question 3 of 9
An enzyme process of producing two identical copies of DNA from one original DNA molecule is called:
Correct Answer: C
Rationale: The correct answer is C: Replication. In DNA replication, the original DNA molecule is unwound and each strand serves as a template to synthesize a new complementary strand. This results in two identical copies of the original DNA molecule. Translation (A) is the process of synthesizing proteins from mRNA. Transcription (B) is the process of synthesizing mRNA from DNA. Cell division (D) is the process of a cell dividing into two daughter cells, not specifically producing identical DNA copies. Therefore, replication is the correct answer as it specifically refers to the process of copying DNA to produce two identical copies.
Question 4 of 9
A gynaecologist was examining a patient and revealed symptoms of genital tract inflammation. A smear from vagina contains pyriform protozoa with a spine, flagella at their front; there is also an undulating membrane. What disease can be suspected?
Correct Answer: A
Rationale: The correct answer is A: Urogenital trichomoniasis. The presence of pyriform protozoa with a spine, flagella at their front, and an undulating membrane in a vaginal smear indicates Trichomonas vaginalis, the causative agent of urogenital trichomoniasis. Trichomonas vaginalis is sexually transmitted and causes vaginal discharge, itching, and inflammation. Lambliasis (choice B) is caused by Giardia lamblia, which is not characterized by the described features. Intestinal trichomoniasis (choice C) is caused by a different species, Tritrichomonas foetus, and presents with diarrhea in cattle. Toxoplasmosis (choice D) is caused by Toxoplasma gondii and typically affects the brain and other organs, not the genital tract.
Question 5 of 9
A 23-year-old man developed a perforation in his hard palate, a dense formation with clear margins was detected in this area. After a surgery, microscopy of excised formation shows there a large focus of caseous necrosis surrounded with a granulation tissue with endovasculitis and a cellular infiltration consisting of lymphocytes and epithelioid cells with predominance of plasma cells. What is the most likely disease in this case?
Correct Answer: B
Rationale: The correct answer is B: Tuberculosis. The case describes a man with a perforation in the hard palate and features of caseous necrosis with granulation tissue, endovasculitis, and a cellular infiltration mainly of lymphocytes, epithelioid cells, and plasma cells. These findings are classic for tuberculosis infection, commonly seen in extrapulmonary sites like the oral cavity. Syphilis (choice A) typically presents with a painless ulcer and different histopathological features. Leprosy (choice C) presents with granulomas containing foamy macrophages. Scleroma (choice D) is caused by Klebsiella rhinoscleromatis and presents with chronic granulomatous inflammation.
Question 6 of 9
A child entering the school for the first time was given Mantoux test in order to determine if there was a need for revaccination. The reaction was negative. What is the meaning of this test result?
Correct Answer: B
Rationale: The correct answer is B: Availability of cell-mediated immunity to tuberculosis. A negative Mantoux test indicates the presence of an immune response to the TB bacteria, as the test measures the body's delayed hypersensitivity reaction to TB antigens. This means the child has been exposed to TB in the past or has been vaccinated, resulting in the development of cell-mediated immunity against TB. Incorrect choices: A: No cell-mediated immunity to tuberculosis - This is incorrect as a negative Mantoux test actually indicates the presence of cell-mediated immunity. C: No antibodies to the tuberculosis bacteria - Mantoux test measures cell-mediated immunity, not antibody response. D: No anti-toxic immunity to tuberculosis - Mantoux test does not assess anti-toxic immunity, it specifically measures cell-mediated immunity.
Question 7 of 9
A wound infection culture revealed Gram-positive cocci in clusters. The bacteria were catalase-positive and coagulase-negative. What is the most likely causative agent?
Correct Answer: A
Rationale: The most likely causative agent in this case is Staphylococcus epidermidis. This conclusion can be drawn based on the characteristics provided: Gram-positive cocci in clusters, catalase-positive, and coagulase-negative. Staphylococcus epidermidis fits all these criteria. Explanation of other choices: - Staphylococcus aureus: Typically coagulase-positive, so it does not match the characteristics given. - Streptococcus pyogenes: Gram-positive cocci in chains, not clusters. Also, it is catalase-negative. - Enterococcus faecalis: Gram-positive cocci in pairs or chains, not clusters. Additionally, it is catalase-negative. Therefore, Staphylococcus epidermidis is the most likely causative agent based on the provided characteristics.
Question 8 of 9
Which bacteria produce exotoxins that can cause severe dehydration and diarrhea?
Correct Answer: A
Rationale: The correct answer is A: Vibrio cholerae. This bacterium produces cholera toxin, an exotoxin that causes severe dehydration and diarrhea by increasing the secretion of electrolytes and water in the intestines. Vibrio cholerae is the causative agent of cholera, a disease characterized by profuse watery diarrhea. Choice B, Clostridium tetani, produces tetanospasmin causing tetanus, not dehydration or diarrhea. Choice C, Escherichia coli, can cause diarrhea but rarely severe dehydration. Choice D, Shigella dysenteriae, produces Shiga toxin leading to bloody diarrhea, not severe dehydration.
Question 9 of 9
Which of the following does NOT describe Cephalosporins
Correct Answer: D
Rationale: The correct answer is D: interferes with protein synthesis. Cephalosporins are beta-lactam antibiotics that work by inhibiting bacterial cell wall synthesis, not protein synthesis. They are bactericidal and have a relatively broad spectrum of activity against various bacteria. Choice A, B, and C all describe characteristics of cephalosporins, making them incorrect options.