ATI RN
openstax microbiology test bank Questions
Question 1 of 9
Which of the following bacteria are capable of forming spores?
Correct Answer: B
Rationale: The correct answer is B, Clostridium botulinum. This bacterium is capable of forming spores, which are dormant, resistant structures that help bacteria survive harsh conditions. Staphylococcus aureus (A), Escherichia coli (C), and Neisseria gonorrhoeae (D) do not form spores. Staphylococcus aureus is a gram-positive bacterium that does not produce spores. Escherichia coli is a gram-negative bacterium that also does not form spores. Neisseria gonorrhoeae is a gram-negative bacterium and does not have the ability to form spores. Therefore, the only bacteria among the options that can form spores is Clostridium botulinum.
Question 2 of 9
What is the structure of the bacterial cell wall?
Correct Answer: A
Rationale: The correct answer is A: Peptidoglycan. Bacterial cell walls are composed of peptidoglycan, a unique macromolecule consisting of sugars and amino acids. This structure provides rigidity and protection to the cell. Lipopolysaccharides are found in the outer membrane of Gram-negative bacteria, not in the cell wall. Phospholipids are the main components of cell membranes, not cell walls. Chitin is a structural polysaccharide found in the cell walls of fungi and some algae, not bacteria.
Question 3 of 9
A patient presents with a history of diarrhea of several weeks' duration. Which of the following may be the cause?
Correct Answer: B
Rationale: The correct answer is B: Yersinia enterocolitica. Y. enterocolitica is known to cause gastroenteritis and diarrhea in humans. It is often associated with contaminated food or water. Bordetella pertussis causes whooping cough, not diarrhea. Corynebacterium diphtheria causes respiratory diphtheria. Neisseria meningitidis is associated with meningitis and septicemia, not diarrhea. Therefore, based on the patient's symptoms and history, Y. enterocolitica is the most likely cause of the diarrhea in this case.
Question 4 of 9
During fibergastroscopy a patient with ulcer disease of the stomach, the mucosal biopsy is taken from the area of an ulcer. Impression smear is prepared from biopsy material and stained by Gram method; the rest of biopsy material is tested for urease activity. Microscopy of the impression smear revealed gram- negative spiral-shaped microorganisms, urease activity test is positive. What bacteria were detected?
Correct Answer: A
Rationale: The correct answer is A: Helicobacter pylori. Rationale: 1. Gram-negative spiral-shaped microorganisms match the morphology of Helicobacter pylori. 2. Positive urease activity is a characteristic feature of Helicjsonacter pylori. 3. Helicobacter pylori is specifically associated with gastric ulcers and is a common pathogen in the gastrointestinal tract. Summary: Choice B, Campilobacter jejuni, is a gram-negative curved bacterium but is not typically associated with gastric ulcers or urease activity. Choice C, Treponema pallidum, is a spirochete bacterium causing syphilis, which is not related to gastric ulcers. Choice D, Spirilla minor, is a generic term for spiral-shaped bacteria and is not a specific pathogen associated with gastric ulcers or urease activity.
Question 5 of 9
Pathological material taken from a patient suffering from pulpitis was inoculated onto Kitt-Tarozzi cultural medium. It is planned to find the following microorganisms:
Correct Answer: A
Rationale: The correct answer is A: Anaerobic. Pulpitis is an inflammatory condition of the dental pulp, often caused by bacterial infection. Anaerobic bacteria are commonly associated with dental infections, making it likely to find them in the inoculated culture medium. Anaerobic bacteria thrive in the absence of oxygen, which is typical of the dental environment. Acid-resistant (B) and acidophilic (C) microorganisms are not specifically linked to pulpitis. Haemolytic (D) microorganisms typically lyse red blood cells, which is not a characteristic feature of bacteria causing pulpitis. Therefore, the most likely microorganisms to be found in the culture medium would be anaerobic bacteria.
Question 6 of 9
A 10-year-old child cut his leg with a glass shard, when playing, and was delivered to outpatient department to receive anti-tetanus serum. To prevent development of anaphylactic shock the serum was introduced by Bezredka method. This method of organism hyposensitization is based on the following mechanism:
Correct Answer: C
Rationale: The correct answer is C: Binding of mast cell-fixed IgE. The Bezredka method involves introducing small amounts of the antigen to which the individual is allergic, leading to the binding of mast cell-fixed IgE. This process desensitizes the immune system and prevents anaphylactic shock by reducing the release of histamine and other mediators from mast cells. Rationale: 1. A: Stimulation of antigen-specific IgG2 is incorrect because the Bezredka method primarily targets IgE, not IgG2. 2. B: Stimulation of the immunological antigen tolerance is incorrect as this method aims to block the allergic response rather than induce tolerance. 3. D: Blocking of mast cell mediators synthesis is incorrect because the Bezredka method does not directly inhibit the synthesis of mast cell mediators, but rather blocks their release by binding IgE.
Question 7 of 9
The territory of an old burial ground for animal refuse that hasn't been used for over 50 years is meant for house building. But soil investigation showed the presence of viable spores of a causative agent causing a very dangerous disease. What microorganism might have been preserved in soil for such a long period of time?
Correct Answer: A
Rationale: The correct answer is A: Bacillus anthracis. This bacterium is known to form highly resistant spores that can survive for long periods in soil. Bacillus anthracis causes anthrax, a dangerous disease that can be transmitted to humans and animals. The other choices, Francisella tularensis, Brucella abortus, and Yersinia pestis, do not form spores as resistant as Bacillus anthracis. Therefore, only Bacillus anthracis is likely to have survived in the soil of the old burial ground for animal refuse for over 50 years.
Question 8 of 9
Which one is NOT included in the etiology of osteomyelitis
Correct Answer: B
Rationale: The correct answer is B: EBV. Osteomyelitis is primarily caused by bacteria, not viruses like Epstein-Barr virus (EBV). The main pathogens involved in osteomyelitis are typically Staphylococcus aureus, including Methicillin-resistant Staphylococcus aureus (MRSA), Haemophilus influenzae, and Pseudomonas aeruginosa. EBV is not a causative agent of osteomyelitis. It is crucial to differentiate between bacterial and viral etiologies in infectious diseases to guide appropriate treatment.
Question 9 of 9
Which of the following is a type of acute infection generally caused by group A Streptococcus?
Correct Answer: C
Rationale: The correct answer is C: Erysipelas. Erysipelas is a type of acute infection caused by group A Streptococcus bacteria. This bacteria infects the upper dermis and superficial lymphatics, leading to a distinct raised, well-demarcated, erythematous skin lesion. The other choices are incorrect because: A Carbuncle is a deep skin infection involving hair follicles, B Impetigo is a superficial skin infection caused by Staphylococcus or Streptococcus bacteria, and D Acne is a chronic inflammatory skin condition not typically caused by group A Streptococcus.