Nokea
Chitin is a component of the cell wall of:
- A. fungi
- B. bacteria
- C. viruses
- D. viruses
Correct Answer: C
Rationale: Chitin is a polysaccharide found in the cell walls of fungi. Bacteria have cell walls made of peptidoglycan, not chitin. Viruses do not have cell walls as they are acellular entities. Therefore, the correct answer is A: fungi.
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Which one is an example of an immunomodulator:
- A. Rifampin
- B. Gamma Interferon
- C. Hexacima
- D. Pentaxim
Correct Answer: B
Rationale: Step-by-step rationale for why B (Gamma Interferon) is the correct answer:
1. Gamma Interferon is a type of immunomodulator that helps regulate the immune response.
2. It activates macrophages and enhances the immune system's ability to fight infections.
3. Rifampin is an antibiotic, not an immunomodulator.
4. Hexacima and Pentaxim are combination vaccines, not immunomodulators.
In summary, Gamma Interferon is the correct answer as it directly influences the immune response, while the other choices are not immunomodulators.
Which of the following bacteria is responsible for causing the disease tetanus?
- A. Clostridium tetani
- B. Clostridium perfringens
- C. Streptococcus pyogenes
- D. Escherichia coli
Correct Answer: A
Rationale: The correct answer is A: Clostridium tetani. This bacterium is responsible for causing tetanus due to its production of tetanus toxin. Clostridium perfringens (B) causes gas gangrene, Streptococcus pyogenes (C) causes strep throat and skin infections, and Escherichia coli (D) is a common gut bacteria that can cause food poisoning but not tetanus.
A 47-year-old male patient consulted a dentist about difficult mouth opening (lockjaw or trismus). The patient has a history of a stab wound of the lower extremity. What infection can be manifested by these symptoms?
- A. Tetanus
- B. Brucellosis
- C. Whooping cough
- D. Anaerobic wound infection
Correct Answer: A
Rationale: The correct answer is A: Tetanus. Tetanus is caused by the bacterium Clostridium tetani, commonly found in soil, dust, and animal feces. The patient's history of a stab wound increases the risk of tetanus infection as the bacterium can enter the body through the wound. Tetanus infection can lead to symptoms such as lockjaw or trismus, which are characterized by muscle stiffness and difficulty opening the mouth. This is due to the neurotoxin produced by Clostridium tetani affecting the muscles.
Summary of incorrect choices:
B: Brucellosis is a bacterial infection transmitted from animals to humans through consumption of unpasteurized dairy products. It does not typically manifest with symptoms of lockjaw.
C: Whooping cough (Pertussis) is a respiratory infection caused by Bordetella pertussis bacteria. It presents with severe coughing fits but does not cause lockjaw.
D: Anaerobic wound infection
On microscopic examination of leftovers of the canned meat eaten by patient with severe food toxicoinfection the following was detected: gram-positive bacilli with subterminal staining defect and configuration alteration of bacilli generally resembling a tennis racket. What agent was detected?
- A. C. botulinum
- B. P. vulgaris
- C. E. coli
- D. S. aureus
Correct Answer: A
Rationale: The correct answer is A: C. botulinum. The description of gram-positive bacilli with subterminal staining defect and tennis racket appearance is characteristic of Clostridium botulinum. The subterminal staining defect indicates the presence of spores, a feature of Clostridium species. The tennis racket appearance refers to the characteristic shape of C. botulinum spores. Choice B, P. vulgaris, is a gram-negative bacterium and doesn't match the description. Choice C, E. coli, is a gram-negative bacillus and doesn't exhibit the subterminal staining defect described. Choice D, S. aureus, is a gram-positive cocci and does not resemble the tennis racket appearance described.
Which bacteria are known to produce an endotoxin that can cause septic shock?
- A. Salmonella enterica
- B. Escherichia coli
- C. Pseudomonas aeruginosa
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D because all three bacteria (Salmonella enterica, Escherichia coli, Pseudomonas aeruginosa) are known to produce endotoxins, specifically lipopolysaccharides in their cell walls. Endotoxins are released upon bacterial cell death and can trigger an immune response, leading to septic shock. Salmonella and E. coli are common causes of bacterial infections, while Pseudomonas is associated with nosocomial infections. Therefore, all of the above choices are correct in terms of producing endotoxins that can cause septic shock. Choices A, B, and C are incorrect individually because they do not encompass all the bacteria known to produce endotoxins that can lead to septic shock.